appendix k – blue green algae prevention control and ... · blue-green algae management plan blw...

GHD | Report for TasWater - Carrick STP New Discharge Pipeline and Outfall , 32/17413

Appendix K – Blue Green Algae Prevention Control and Management Plan

Blue-Green Algae Management Plan

BLW-BGA Plan-V07 Approved: 14 Dec 2011 Page 1 of 64

Review 31 Jan 2013 TRIM :

Blue Green Algae

Prevention

Control and

Management

Plan




DOCUMENT HISTORY & VERSION

CONTROL RECORD

Tasmanian Water and Sewerage Corporation

(Northern Region) Pty Ltd

ABN 13 133 655 062

Name of Document: Blue-Green Algae Prevention, Control & Management Strategy

Author: W. Wood

Authorised Officer: A. Truscott

Description of content: Management Strategy

Approved by: A. Truscott

Date of approval: 14 December 2011

Assigned review period: Annual

Date of next review: 31 January 2013

Is the document current? Yes No

Has a review occurred

within assigned period?

Yes No

Version

Number

Version

Date

Authorised

Officer

Amendment Details

1 Oct 2010

2 Dec 2010 Inserted Executive Summary & Tables

3 April 2011 Final Review & Table Update

4 July 2011 Incorporating approved actions for 2011/12

5 July 2011 Editorial comments update

6 Nov 2011 Editorial comments, minor internal re-

structure

7 Dec 2011 A. Truscott Approved for EPN issue




Contents

1 Executive Summary 5

2 Introduction 8

2.1 Ben Lomond Water, Water Supply Systems ............................................................ 8

2.2 Ben Lomond Water, Waste-Water Treatment Systems ............................................ 9

2.3 Tasmanian Environmental Protection Authority Blue Green Algae Guidelines ....... 10

2.4 Health Effects of Blue Green Algae ........................................................................ 12

2.5 Indicators for a potential BGA bloom formation include: ......................................... 12

2.6 The Principal Factors that will Support BGA Blooms Include: ................................ 13

2.7 Phases of a Bloom ................................................................................................. 13

2.8 Blue Green Algae History and Control in BLW Wastewater Treatment Facilities. ... 15

3 Risk Assessment for Growth of Blue Green Algal Blooms in BLW Facilities 16

3.1 BLW Risk Assessment Process ............................................................................. 16

3.2 Enhanced Risk Assessment Process ..................................................................... 17

3.3 Outcomes of the Risk Assessment Process ........................................................... 17

3.4 Further Assessments ............................................................................................. 18

3.5 Overall Action Priority ............................................................................................ 21

4 Action Program 22

4.1 Individual Waste Water Treatment Plant Details: ................................................... 25

4.2 Available Actions: .................................................................................................. 25

4.2.1 Bloom Prevention: ............................................................................................ 25

4.2.2 Controlling Developed Blooms .......................................................................... 26

5 Documentation of Controls, Materials and Methods 27

5.1 Sludge Management .............................................................................................. 27

5.2 Emergency irrigation .............................................................................................. 27

5.3 Mechanical methods to prevent or control blooms ................................................. 28

5.4 Chemical methods to prevent or control blooms .................................................... 28

5.5 Blue-Green Algae blooms – Summer 2010/11 ....................................................... 29

5.6 Blue-Green Algae Blooms – Summer 2011/12 ....................................................... 30

6 Routine Sampling for Blue-Green Algae. 31

6.1 Representative Bloom Sampling ............................................................................ 31




6.2 Sampling to Characterise Species Present and Toxicity ........................................ 32

6.3 Methods for Sampling ............................................................................................ 32

6.3.1 Sampling at an outfall ....................................................................................... 32

6.3.2 Sampling within a body of water........................................................................ 33

6.4 Trigger Levels ........................................................................................................ 34

6.4.1 Sampling Results and Trigger Values ............................................................... 35

6.5 Responsibilities ...................................................................................................... 37

6.5.1 Executive Manager Service Delivery ................................................................. 37

6.5.2 Regional Managers and Waste Water Manager ................................................ 37

6.5.3 Coordinators and Plant Operators ..................................................................... 38

7 Individual Action Plans 39

7.1 Action Plans - General ........................................................................................... 39

Appendix A Blue Green Algae Blooms, Water Nutrients and Sludge Status Information 40

Appendix B Emergency Irrigation Opportunities 42

Appendix C 2011-12 - Individual Plant Action Sheets 44

Appendix D Plant Specific history Sheet 55

Appendix E Ben Lomond Water Business Management System Risk Assessment Matrix 57




1 EXECUTIVE SUMMARY

This document responds to the potential for Blue-Green Algal (BGA) blooms to form in Ben

Lomond Water’s (BLW) waste water treatment plant (WWTP) lagoons systems.

The document addresses both prevention and the mitigation of BGA blooms. It approaches

the management of potential BGA bloom formation through a priority action plan based on a

risk-assessment process. Priorities have been ranked by two separate processes and then re-

assessed on the basis of potential management options. These have included options for

irrigation or the utilisation of installed, or re-deployed, infrastructure being available.

The main risk is for BGA to interfere directly or indirectly with the waste water treatment

process through an inability to discharge effluent, and/or the potential to cause environmental

harm through the contamination of restricted inland waterways, impacts on stock or water

abstraction or other environmental impacts.

An outcome of these assessments has been the development of a BGA response matrix. This

looks at parameters such as sludge content, the available discharge location, ability to store

effluent, possible control options and then a re-assessment based on the availability of an

associated irrigation scheme.

This process has identified five plants perceived to be most at risk from BGA bloom formation

and that at present have either restrictive discharge options and/or no associated re-use

irrigation opportunity.

These plants have been given a High Priority and they are:

• Prospect Vale; • Scamander; • Bridport; • Westbury; • Carrick; • Longford; • Beaconsfield; • Deloraine; and • Evandale

It is recognised that the availability of irrigation provides significant mitigation against the risks

associated with BGA blooms. Of the listed plants, Prospect Vale is most at risk on account of

a lack of any alternative discharge option, Carrick has a partially developed irrigation scheme.

Scamander is entirely reliant on irrigating a golf course with the only alternative discharge

being to a barred estuary, while Bridport relies on a seasonal golf course discharge but

otherwise discharges via a broken marine outfall. Attention to lagoons management and the

operations of the Dissolved Air Flotation (DAF) plant is expected to manage the threat of BGA

bloom formation at Westbury.




Prevention methods include management of effluent residence time in lagoons, attention to

sludge build-up in lagoons and interference with the BGA life cycle through the introduction of

organisms that compete for nutrients in the sludge and mechanical disturbance of the water

column to promote vertical mixing and thus to prevent formation of a thermocline.

Strategies that will be put in place over the 2011/12 year include:

Prospect Vale Management of residence time of effluent within lagoons by selectively

reducing the number of lagoons in the treatment pathway;

Scamander Introduction of mixer/aerators into the lagoons to disrupt development of

a thermocline;

Bridport Installation of a Bioamp system to the main Bridport pumping station

immediately downstream of lagoons and the continuing assessment of

its benefits and efficiency;

Carrick Development of a treated wastewater reuse program on an adjoining

farm property;

Westbury Management of lagoon levels to optimise use of the installed DAF system.

The efficiency of each of these strategies will be carefully monitored to assist in informing

further action programs.

This strategy document recognises the relationship between phosphate levels held within the

sludge layer within lagoons, the potential for stratification within the lagoons in warmer

weather and the life cycle and “behaviour” of BGA propagules within the lagoon water column.

It is now well accepted in the scientific literature that the relationship between sludge build-up

and the presence of nuisance BGA is positively correlated.

Ben Lomond Water has developed a separate Biosolids Management Plan and is now moving

to develop an integrated program for the management of sludge within lagoons and the

ultimate reuse of Biosolids for beneficial purposes as envisaged by the Tasmanian Biosolids

Reuse Guidelines 1999.

In addition it is also recognised that the disruption of stratification by mixing interferes with the

photosynthetic capability, and thus productivity, of BGA propagules as they rise and sink

within the water column. Control methods include the disposal of contaminated water through

emergency, or other, irrigation, isolation and containment of blooms within lagoons taken off

line, the use of chemical and biological controls and mechanical controls such as aeration or

ultra-sound.

As indicated above, Ben Lomond Water is installing, and will be monitoring, the effectiveness

of a number of control mechanisms over the 2011/12 season.




The Ben Lomond Water Blue-Green Algae Prevention, Control and Management Strategy

sets out an action program with the principal aim of pre-emptive action to reduce the risks of

bloom forming. This is achieved through an escalation of a range of preventative actions

including de-sludging, lagoon isolation, chemical dosing or mechanical mixing. In the event

that a bloom does form, then options to reduce or control this are then provided. These

options depend upon lagoons capacity and on installed, or deployment capability of,

infrastructure such as chemical dosing or agitation/aeration facilities.

Past history of blooms together with routine sampling for the presence of BGA is essential, for

effective control sampling should commence by early spring. The most effective control for

BGA is essentially provided by managing optimum sludge levels in the Corporations’ waste

water systems and by providing early planning for potential BGA development ahead of the

summer and autumn seasons.




2 INTRODUCTION

Blue-green algae, or cyanobacteria, are simple microscopic organisms that exist as

unicellular, filamentous and colonial life forms and are capable of colonising a very wide range

of aquatic habitats. Despite the name, Blue-green algae (BGA) have an entirely different

cellular structure and are not related to higher plants such as the green algae but are an older

life form more closely related to free-living bacteria. This is an important distinction as the

“behaviour” of BGA in a water body, and thus their control, will differ from that required to

control growth of motile, colony forming or filamentous green algae such as Euglena, Volvox

or Cladophora.

BGA are increasingly becoming a problem in natural waterways, in water storage and supply

systems and in waste water treatment facilities.

In the wider environment BGA respond to raised levels of nutrients from urban or agricultural

run-off and widespread blooms may be triggered. In addition to the Chlorophyll a present in all

photosynthetic plants including the green algae, BGA also contain additional photosynthetic

pigments that can harvest light in the green, orange and yellow parts of the solar spectrum. In

addition some genera of BGA may also vary their position within the water column by either

producing gas to rise in the water or through the production of carbohydrates which cause

them to sink. These photosynthetic and behavioural adaptations give the BGA a competitive

advantage over green algae and allow them to dominate affected water bodies. Dense blooms

within the water body may thus out-compete other species for light and darken the water body

to a point where plants attached to the bottom may die out. In this way BGA blooms have

dramatically altered the ecology of a number of inland Australian waterways.

2.1 BEN LOMOND WATER, WATER SUPPLY SYSTEMS

In the water supply situation, blooms of BGA may result in offensive tastes and odours in the

water supplied to households. While all BGA are not necessarily toxic, under some

circumstances a range of toxins may be released from algae blooms and in particular from

damaged or decaying algae. In some instances, toxins released from BGA blooms have been

documented as the causal factors leading to serious deleterious effects, including death, in the health and wellbeing of both humans and animals that drink the contaminated water.

BGA blooms in water supplies tend to be in the larger storage dams and, in Tasmania, have

not emerged as a problem in un-roofed storage reservoirs. BGA blooms have become a

periodic problem in Tasmania in water bodies such as Curries River Dam and Lake Trevallyn.

This has especially been the case during the warmer summer months with little freshwater

input into the lake. BGA blooms in Lake Trevallyn present added problems for water treatment

for the Mount Leslie and West Tamar Water Supply treatment facilities. To combat the

potential for tainted water, Ben Lomond Water doses with powdered activated carbon to




remove this. BGA may also affect public utilisation of Lake Trevallyn and restrict swimming in

the First Basin pool.

2.2 BEN LOMOND WATER, WASTE-WATER TREATMENT SYSTEMS

In the waste water treatment plant context, BGA cells are able to survive in the water column

or the sediments in low numbers over less favourable conditions, such as winter, and then

increase rapidly in response to environmental stimulants such as anoxic sediments, high

nutrients levels and the bright sunlight and increasing water temperatures associated with

spring and summer. If unchecked, these population explosions may result in dense blooms

that cover the surface of lagoons and interfere with the waste water treatment processes. The

presence of dense blooms also affects the ability to discharge treated effluent to inland water

courses while blooms persist. In addition the decomposition of blooms may lead to the release

of toxins into the environment.

It is the potential for the contamination of receiving water bodies with BGA and the possible

release of toxins capable of harming livestock and humans and the contamination of water

supplies that is the reason for the application of regulatory controls on BGA infected waters.

BGA have now become established in a number of the BLW lagoons based waste water

treatment plants over the last several years and annual recurrences of blooms is now

anticipated. A summary of the status of BGA in each lagoons-based system in 2009/10 is

provided in Table 1. Local climatic conditions that occurred over the 2010/11 season did not

appear to favour the degree of BGA bloom formation witnessed in 2009/10, despite this it is

assumed that the 2009/10 data are representative of lagoons systems where future BGA

bloom activity should be anticipated.

The concentration of BGA cells/mL that may be discharged to the environment is regulated on

a plant by plant basis by the Tasmanian EPA. The notification levels for BGA counts varies

from plant to plant, but in general counts that exceed 11,500 cells/mL require notification to

the EPA and toxicity testing is required prior to any discharge being approved.

The primary drivers of blue green algae blooms are high levels of Phosphate [P] in the water

column and sediments, long daylight hours, stratified water columns with strongly developed

thermo-clines and heated surface layers, anoxic sediment conditions and the associated

release of phosphorus from the sediments.




2.3 TASMANIAN ENVIRONMENTAL PROTECTION AUTHORITY BLUE GREEN ALGAE GUIDELINES

In March 2011, the Tasmanian EPA issued “Guidelines for Managing Blue Green Algae

(Cyanobacteria) Blooms in Sewage Treatment Lagoons”.

Ben Lomond Water acknowledges the work embodied in this document and draws on this,

and other, works in the development of our Ben Lomond Water Blue-Green Algae Prevention,

Control and Management Strategy

.




Table 1 Lagoons-Based Plants

Blue green Algae response matrix

History of BGA Blooms Options matrix

Cell Counts Y/N 2009/10 Power Strategy Discharge to? Lagoon Emergency Chemical Aerator Immediate Longer

WWTP 2009/10 2010/11 Sludge % Irrigation scheme available Rank redundancy?Irrigation ? Option? Option Priority Term

Evandale 10,000,000.00 34% Yes Yes 6 small creek Possible Yes ?? Power Upgrade plant?

Legana 4,900,000.00 30% Yes No 12 small creek Possible Yes no power Connect to power

Lilydale 4,300,000.00 no data Yes Yes 21 small creek Possible Yes ?? Power

Scamander 4,000,000.00 no data Yes Golf course Yes 2 Barred estuary Yes Yes ?? Power H Install agitation

Westbury 3,000,000.00 30% No Yes 9 small creek No Possible H

Perth 2,300,000.00 Yes 16% Yes Limited 20 River Possible Yes no power

Beaconsfield 1,200,000.00 29% No No 5 small creek No no under review

Exeter 461,000.00 26% Yes Golf course ? 11 small creek Possible no

Carrick 280,000.00 no data No Yes 15 River No Yes H Re-use scheme

St Marys 280,000.00 45% Yes Yes 13 small creek No Possible Possible Review reuse scheme

Beauty point 252,000.00 28% Yes Yes 10 estuary Yes Possible Possible

Prospect Vale 136,000.00 44% No Yes 1 small creek Yes Possible Possible Possible H To Greater Launceston

Cressy 83,000.00 18% Yes Yes 18 small creek No

Bridport 31,800.00 Yes 57% Yes Golf course No (Generator?) 4 Marine No No BioAmp? no power H Dune infiltration ?

Deloraine 28,000.00 59% No Yes 7 River No Possible under review

Fingal 27,000.00 no data No Yes 8 River No No Yes Possible

St Helens minor 20% No Yes 16 estuary No No No No

Campbell Town 37% Yes Yes 17 River Yes Possible Possible

Stieglitz 25% Yes Yes 14 None No Possible Possible

George Town no data No Yes 19 estuary Possible No Possible Possible under review

Longford 67% No Yes 3 small creek Yes Yes Re-use scheme

Ross no data No Yes N/A small creek No Possible Possible Possible De-sludge lagoon

Kalangado no data No No N/A None No No Possible Possible

Nile Full No No N/A small creek No Possible Possible no power De-sludge

Western Junction no data No No N/A small creek No Possible Possible ?? Power Upgrade w/- Evandale?

Installed irrigation

Golf course Irrigation

Plants requiring action

Risk ranking is obtained from Table 3 Ben Lomond Blue Green Algae Strategy.

Carrick is elevated for early action on account of existing re-use effluent storage infrastructure and a need to re-locate the outfall tom the Meander River.

Notes: Cell counts are for highest that year; sludge % is a mean value for the worst lagoon and lagoon redundancy refers to the ability to take a lagoon off-line to de-sludge.




2.4 HEALTH EFFECTS OF BLUE GREEN ALGAE

Under some circumstances, that are poorly understood, BGA may produce a range of toxins

that are capable of serious health consequences for humans or for live-stock. While blooms

may often be inert in terms of toxin production, where toxins are present these are generally

released when the cells die or are damaged. There are two main groups of BGA toxins,

these being cyclic peptides such as Microcystins and Nodularin and alkaloid groups such as

the Anatoxins, Saxatoxin and Cylindrospermopsins.

The cyclic peptide groups affect the liver and may be carcinogenic while the Alkaloids affect

the nervous system, the skin, liver, kidneys and may also be carcinogenic and genotoxic.

2.5 INDICATORS FOR A POTENTIAL BGA BLOOM FORMATION INCLUDE:

• A previous bloom history;

• Excessive build-up of sludge in the lagoons, usually >30%;

• High levels of phosphate in the water column; and

• Excessive retention time within the lagoons system.

BGA blooms may be prevented by removing, or otherwise controlling one or a number of the

above factors.

The control of blooms once they become established is more difficult and may be very

costly.




2.6 THE PRINCIPAL FACTORS THAT WILL SUPPORT BGA BLOOMS INCLUDE:

• The re-working of sludge under anoxic conditions and the release of sequestered

nutrients N & P;

• Stratification in the water column (formation of a thermo-cline);

• High nutrient concentrations in received effluent;

• Raised air temperatures

• Long day-length and sunlight hours;

• Long residence time of effluent in the lagoon system; and

• Periods of calm or stable meteorological conditions.

The Potential for the onset of an algal bloom may be based upon a number of environmental

parameters, one approach to the assessment of the risk for bloom formation is provided in

Table 2 below.

Environmental Factor Potential for BGA Growth

History of BGA Water temperature 0C

Nutrients Total P µg/L

Thermal Stratification

Very Low No <15 <10 Rare or never Low Yes >15-20 <10 Infrequent Moderate Yes 20-25 10-25 Occasional High Yes >25 25-100 Frequent and

Persistent Very High Yes >25 >100 Frequent and

Persistent/strong

Table 2 Assessment of the potential for cyanobacterial growth based on environmental

parameters (WQRA 2010).

2.7 PHASES OF A BLOOM

Bloom development follows a series of phases these include: an early initial development

phase; followed by an exponential growth phase when productivity is maximal and a plateau

phase when maximum bio-mass is reached and bio-mass limits productivity. The bloom

finally concludes with a die-off phase, a stage when increased levels of toxins may be

released. The plateau phase may persist for an extended period if the appropriate

environmental conditions also persist.

The relationship with day-length, maximum productivity and algal biomass is shown in Fig 1.

It is clear that the exponential growth phase closely follows the spring equinox and maximum

productivity is reached before mid-summer. At that time the algal bio-mass is still increasing

and peaks after mid-summer. At that time with decreasing day-length, the algal bio-mass

effectively limits productivity through self-shading. As the autumn equinox is approached

productivity collapses and bio-mass rapidly diminishes. The period most at risk for the

release for toxins is when the blooms collapse with the approach of autumn. The most

effective period to manage systems to prevent the formation of blooms is at the




commencement of the exponential growth phase. Control of established blooms will extend

over the period between reaching peak productivity and the formation of maximum bio-mass.

0

5

10

15

20

25

0 100 200 300 400 500 600 700 800

day length

Productivity

Biomass

Austral Spring Equinox Summer Solstice

Fig 1 The relationship between day-length (blue diamond’s) Productivity (red squares) and

bio-mass (green triangles) is shown.

X axis: Day number is on the x axis and commences on mid-summer day (day number

equals 1), mid-winter (first mid-winter day number equals 172) and the Equinoxes are the

other points. Two seasonal cycles are followed.

Y axis: Values on the Y axis are hours between sun-rise and sunset, with 9 hrs for mid-

winter and 15.4 hrs for mid-summer for Hobart (Blue Diamonds). Hypothetical values for

productivity (Red Squares) and bio-mass (Green Triangles) are fitted to the same Y axis

(after Wood 1987).




2.8 BLUE GREEN ALGAE HISTORY AND CONTROL IN BLW WASTEWATER TREATMENT

FACILITIES.

The BGA bloom history, nutrient status, sludge content and potential for irrigation for the

BLW waste water systems that utilise lagoons is shown in Appendix A. These are factors

that will vary from year to year and as a consequence BLW will regularly maintain the

information presented here in Appendix A.

BLW operates 20 Level 2 and 4 Level 1 waste water treatment plants that utilise lagoons. Of

these, 12 systems discharge treated to full, or partial, effluent re-use schemes. None of the

Level 1 plants are associated with any re-use scheme.

Discharge of BGA-contaminated water to existing effluent re-use schemes is acceptable

providing that appropriate precautions with respect to withholding periods for stock access to

pasture irrigated with BGA-affected water are adhered to.

Those Level 2 plants where no current effluent re-use scheme is in place are listed in

Appendix B. This table indicates whether there has been a past emergency arrangement or

whether it is considered that there is a potential for an emergency program to be developed.

The establishment of emergency irrigation programs requires an agreement with a local land

owner to accept the waste and for the establishment, or the provision, of suitable pumps,

pipes and irrigation equipment.

Importantly the establishment of an emergency irrigation program requires a detailed

assessment process to be undertaken and a form of DP&EMP to be submitted to the EPA.

Under some circumstances, approval may be with-held or may not necessarily be available

within a relatively short period.




3 RISK ASSESSMENT FOR GROWTH OF BLUE GREEN ALGAL BLOOMS IN BLW

FACILITIES

An appropriate means by which to direct an action program to prevent or to control BGA

blooms is through an assessment of the environmental, social and corporate risks

associated with the development and presence of blooms in Ben Lomond Waste Water

facilities.

Two distinct methodologies have been used to assess the risk of development of Blue-

Green Algae blooms.

3.1 BLW RISK ASSESSMENT PROCESS

The Ben Lomond Water Business Management System, Environmental Aspects and

Impacts document provides criteria for performing risk assessments.

This methodology provides descriptors for the likelihood of an event occurring and also a

range for the environmental, public health, occupational health and safety, consequences

and the consequences for the business in terms of infrastructure, delivery of service,

compliance, reputation of the organisation and financial impacts. These range from

“insignificant” to “catastrophic”.

This approach assesses the risk to the business from Blue-Green Algal blooms against 7

major criteria, these are:

• Financial Implications;

• Occupational Health and Safety;

• Impact on BLW Assets;

• Deterioration in Water Quality and Public Health;

• Impacts to our Service Delivery;

• Impacts on BLW’s reputation;

• Impacts on the Environment; and

• Implications for Compliance.

A risk matrix series for each of these characteristics is presented in Appendix E. A summary

of the outcomes of this assessment is provided in Table 3.




3.2 ENHANCED RISK ASSESSMENT PROCESS

An extension to this approach of assessing risk has been to consider a number of factors for

each plant including the likelihood of a bloom forming, the potential negative consequences

of a bloom to the community, environment and the business and the controls available to

BLW to prevent or manage the formation of algal blooms. This latter process provides a

score for each plant with respect to the formation and management of blooms and also

ranks all plants in terms of their relative risk of bloom formation and the consequences of

bloom formation. These data are shown in Table 4.

Risk factors listed in Table 4 were derived from a consultative process with operational staff,

they include a presentation of four blue-green algae bloom formation “likelihood” factors and

an additional five “consequence” factors.

The ensuing “Risk Level” is the product of each plant “likelihood” score and its corresponding

“consequence” score. Potentially diminishing this “Risk Level” are a number of “Control

Factors” that may be presently available or may be applied to reduce the impact of BGA

blooms.

The final “Residual Score” is the “Risk Level” minus the “Control Factor Score” (for example

for the Lilydale WWTP the “Likelihood Score” times the Consequence Factor Score” is 3*2 =

6. The Control factor score is 2.6, thus the “Residual Score” is then 6 - 2.6 = 3.4).

Finally plants are ranked from that most at risk = 1 to that deemed least at risk of BGA

blooms = 21 (Table 4).

Information used to provide the criteria to make this assessment have been obtained from

plant performance records and information provided by plant operators.

3.3 OUTCOMES OF THE RISK ASSESSMENT PROCESS

A feature of the two approaches to risk evaluation has been the general agreement in

identification of the plants most at risk of producing negative outcomes from BGA bloom

formation (Table 4) and those that also present as “moderate” risks to a range of aspects of

the BLW business (Table 3).

Both processes identified Prospect Vale and Scamander as plants with an inherent high risk

to the business, the environment and the community from BGA bloom formation.

Plants where “moderate” impacts on Assets are considered to be “Likely” include Prospect

Vale and Longford.

“Moderate” Impacts on water quality are considered “likely” at Scamander; while “Moderate”

impacts to the environment are considered to be “possible” at Scamander and Prospect

Vale.




Prospect Vale, Scamander, Longford, Bridport and Beaconsfield are identified through the

second risk assessment summarised in Table 4.

3.4 FURTHER ASSESSMENTS

At the present time any broad industry or regulatory assessment of long-term effects on

irrigation of public open spaces with Blue-Green Algae containing effluent or of soils,

agricultural practices or grazing livestock are not yet available. Over the last decade

however a number of scientific studies are now being undertaken and published papers are

gradually becoming available, examples being:

Peuthert, A., S. Chakrabarti and S. Pflugmacher (2007)

Uptake of Microcystins-LR and –LF (Cyanobacterial toxins) in seedlings of several important

agricultural plant species and the correlation with cellular damage (lipid peroidation).

Environmental Toxicology 22:4436-442

Sagrane. S., Y Ouahid, I.El Ghazali, B. Oudra, L. Bouarab and F.F. Del Campo (2009),

Physiological changes in Triticum durum, Zea Mays, Pisum sativum and Lens esculenta

cultivars, caused by irrigation with water contaminated with Microcystins: A laboratory

experimental approach. Toxicon 53:786-796

McElhiney J. L.A. Lawton, and C. Leifert. ( 2001)

Investigations into the inhibitory effects of Microcystins on plant tissues following exposure.

Toxicon. 39:1411-1420

Yiasoumi, B., J. Gillett, and C. Bourke (2009)

Managing blue0green algae in farm dams. NSW Department of Primary Industries.

www.dpi.nsw.gov.ay/primefacts




Table 3 Ben Lomond Water Business Management System Environmental Aspects

and Impacts Risk Assessment Matrix Summary (Appendix A)

Consequence

Consequence Descriptor

Insignificant Minor Moderate Other

Financial Almost Certain Carrick, Bridport, Legana, Exeter, Beauty Point, Beaconsfield

Prospect Vale, Scamander, Westbury.

Nil

Likely Deloraine, St Marys, Fingal, Longford

Nil

Possible Cressy, Evandale, Perth, Stieglitz, St Helens, George Town.

Nil

Assets Likely Prospect vale, Longford

Nil

Possible Fingal Cressy, Evandale, Perth, St Marys, Westbury, Legana, Exeter, Beauty Point.

Carrick, Deloraine, Scamander, Beaconsfield.

Nil

Unlikely Campbell Town, St Helens, Stieglitz, George Town, Lilydale.

Bridport Nil

OH&S Possible All Plants Nil

DWQ/Public Health

Likely Prospect vale, Beaconsfield.

Scamander Nil

Possible Bridport, St Helens, Longford.

Nil

Unlikely Campbell Town, Cressy, Evandale, Perth, Carrick, Stieglitz, St Marys, Lilydale, Legana, Exeter, Beauty Point.

Deloraine, Fingal, Westbury.

Nil

Rare George Town Nil Service Delivery

Likely Prospect Vale, Scamander.

Nil

Possible Bridport, St Helens, Longford.

Nil

Unlikely Campbell Town, Cressy, Evandale, Perth, Carrick, Stieglitz, St Marys,, Lilydale, Legana, Exeter, Beauty point

Deloraine, Fingal, Westbury, Beaconsfield.

Nil

Rare George Town Nil Reputation Possible Longford, Scamander,

Prospect Vale. Nil

Unlikely Campbell Town, Cressy, Evandale, Perth, Carrick, Stieglitz, St Marys, Lilydale, Legana, Exeter, Beauty Point, Fingal, Beaconsfield, Bridport.

Deloraine, Westbury, St Helens.

Nil

Environment Likely Nil Possible Longford, Scamander,

Prospect vale. Nil

Unlikely Campbell Town, Cressy, Evandale, Perth, Carrick, St Marys, Lilydale, Legana, Exeter, Beauty Point, Fingal, Bridport.

Stieglitz, Beaconsfield, Deloraine, Westbury.

St Helens. Nil

Rare George Town Nil Compliance Possible Longford,

Beaconsfield, Deloraine, Westbury

Nil

Unlikely Campbell Town, Cressy, Evandale, Perth, Carrick, St Marys, Lilydale, Legana, Exeter, Beauty Point, Fingal, Bridport.

Stieglitz. Nil

Rare Unlikely Nil




Table 4 Risk Analysis for Ben Lomond Level 2 Waste Water Treatment Plants.

liklihood factors consequence factors control factors

pre

vio

us

his

tory

sludge b

uild u

p

phosp

hate

levels

long rete

nti

on tim

es

liklihood s

core

pri

mary

conta

ct /

public

healt

h

public

resp

onse

rece

ivin

g e

nv. co

ndit

ion

volu

me

reci

evin

g e

nv. diluti

on

score

risk

level

stora

ge

rete

nti

on tim

e reduct

ion

reuse

em

erg

ency

irr

igati

on

treatm

ent /

dosi

ng /

agit

ati

on

score

resi

dual ri

sk

rankin

g

Lilydale 5 2 2 3 3.00 1 1 2 2 4 2 6.00 3 2 4 4 0 2.6 3.40 21

Perth 4 1 4 3 3.00 2 2 3 3 2 2.4 7.20 3 2 4 4 3 3.2 4.00 20

George Town 1 4 1 3 2.25 2 3 3 4 1 2.6 5.85 3 2 0 0 4 1.8 4.05 19

Cressy 4 1 3 3 2.75 2 2 2 1 5 2.4 6.60 2 2 4 4 0 2.40 4.20 18

Campbell Town 1 4 3 3 2.75 3 2 3 3 3 2.8 7.70 3 2 4 4 3 3.2 4.50 17

St Helens 1 2 1 5 2.25 4 4 4 3 1 3.2 7.20 3 3 0 1 5 2.4 4.80 16

Carrick 5 3 2 3 3.25 2 2 3 3 2 2.4 7.80 4 3 0 4 2 2.6 5.20 15

Stieglitz 3 3 5 3 3.50 2 3 2 2 2 2.2 7.70 2 1 4 4 1 2.4 5.30 14

St Marys 5 5 3 3 4.00 1 1 2 2 4 2 8.00 3 2 4 4 0 2.6 5.40 12

Legana 5 4 4 3 4.00 1 1 2 4 2 2 8.00 3 2 4 4 0 2.6 5.40 12

Exeter 5 3 4 3 3.75 3 2 2 3 1 2.2 8.25 3 2 3 3 0 2.2 6.05 11

Beauty Point 5 3 4 3 3.75 4 3 4 2 1 2.8 10.50 4 2 4 4 3 3.4 7.10 10

Westbury 5 3 1 3 3.00 4 2 2.5 3 4 3.1 9.30 3 2 0 2 3.5 2.1 7.20 9

Fingal 5 4 3 3 3.75 3 2 3 1 1 2 7.50 1 0 0 0 0 0.2 7.30 8

Deloraine 3 5 2 3 3.25 3 3 3 3 2 2.8 9.10 2 2 0 2 0 1.2 7.90 7

Evandale 4 4 4 3 3.75 2 2 2 3 5 2.8 10.50 3 1 4 4 0 2.40 8.10 6

Beaconsfield 5 3 4 3 3.75 2 2 2 1 5 2.4 9.00 1 1 0 0 2 0.8 8.20 5

Bridport 5 5 5 1 4.00 4 4 4 3 1 3.2 12.80 3 1 3 3 0 2.0 10.80 4

Longford 3 5 5 3 4.00 4 3 3 5 2 3.4 13.60 3 2 0 3 4 2.4 11.20 3

Scamander 5 4 4 3 4.00 5 5 3 4 3 4 16.00 4 2 2 2 0 2.0 14.00 2

Prospect 5 5 4 5 4.75 5 5 2.5 5 2 3.9 18.53 4 2 0 2 3 2.2 16.33 1

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00

LilydalePerth

George TownCressy

Campbell TownSt Helens

CarrickStieglitz

St MarysLeganaExeter

Beauty PointWestbury

FingalDeloraineEvandale

BeaconsfieldBridport

LongfordScamander

Prospect

Series1



Review 31 Jan 2013

3.5 OVERALL ACTION PRIORITY

BLW have created a priority list of waste water treatment plants based on risk ranking and

available mitigation measures (i.e. availability of emergency discharge). The priority list is as

follows:

• Prospect Vale;

• Scamander;

• Bridport;

• Westbury;

• Carrick;

• Longford;

• Beaconsfield;

• Deloraine; and

• Evandale.



Review 31 Jan 2013

4 ACTION PROGRAM

Ben Lomond Water’s primary aim to manage BGA blooms is to implement pre-emptive action

to reduce the risk of algal bloom formation.

Where plants have a history of blooms and other factors such as a high proportional sludge

content (Appendices A and B) and high levels of nutrients, preventative action must be taken

early in the season if blooms are to be prevented or controlled. Action should ideally be taken

as early as September ahead of the Spring Equinox (See Fig. 1) and the commencement of

warmer weather and longer spring and summer days.

If blooms develop, despite preventative action, a strategy to further manage and control these

will be then required.

Control of developing blooms may be achieved through an escalation of the preventative

actions. In the event that control measures fail, disposal of affected effluent may be possible

through negotiation of an emergency irrigation program with the EPA and landowners.

Figure 2 provides a Blue Green Algae Prevention and Management Decision Tree for all

waste water treatment facilities. Controls for lagoons-based plants at this stage rely on

existing irrigation schemes or the early approval of emergency irrigation schemes for the

disposal of effluent. Where there is a history of bloom formation a control program is then

invoked (Fig 3).

Figure 3 provides a Blue Green Algae Control Program. This program is based on an

assessment of the risk of bloom formation as set out in Table 3. Risk is based upon a number

of likelihood and consequence factors and the control factors available at each plant.

Figure 3 identifies a number of strategies that can be followed to prevent or control BGA

blooms. These are elaborated on in sections 4 and 5.


BLW-BGA Plan-V07

No Approved Reuse Scheme

Emergency Irrigation potential

Investigate feasibility

Available

Seek EPA Approval

Rely on emergency re-

use

Actuate Land Management

controls

Not Immediatly Available

See Separate Flow Chart (Fig 3)

Activation of Control Measures (Section 3)

Timing

by September

Green Algae Management Plan

Approved: 14 Dec 2011

Review 31 Jan 201

FIGURE 2

BLUE GREEN ALGAE PREVENTION & MANAGEMENT DECISION TREE

Plant Type

Utilises Lagoons

BGA last 3 years?

Yes

No Approved Re-use Scheme

Not Immediatly Available

See Separate Flow Chart (Fig 3)

Activation of Control Measures (Section 3)

Timing

by September

No emergency Irrigation potential

Partial Re-use Scheme

Full Re-use with storage

Rely on existing re-use

Scheme

No

Mechanical

No Action

Monitor discharge and

water body

Page 23 of 64

2013

BLUE GREEN ALGAE PREVENTION & MANAGEMENT DECISION TREE

Mechanical

No Action

Monitor discharge and

water body


BLW-BGA Plan-V07

No Blooms

Consider Application of Early Season

Preventative Measures (Section 3)

Sludge Depth <25%

No Immediate Action

Monitor BGA Cells and [P]

If BGA & [P] Increase or

Blooms Start to Form

Green Algae Management Plan

Approved: 14 Dec 2011

Review 31 Jan

FIGURE 3

BLUE GREEN ALGAE CONTROL PROGRAM

Lagoons Systems

Lagoons With an Existing BGA

History

Evaluate Risk to Operations

& the Environment

Residual Risk Factor >5

Considered to be high

No Blooms

Consider Application of Early Season

Preventative Measures (Section 3)

Sludge Depth > 25%

Remove Sludge if Possible;

Isolate Lagoon;

Install Aeration;

Emergency irrigation;

Filter Discharges;

Install Chemical Controls

If Blooms Still Develop

Notify EPA

Monitor

Advise Affected Parties

Blooms Present

Notify EPA

Advise affected parties

Initiate Control Measures for Existing

Blooms

Take Lagoon Off-Line;

Emergency Irrigation;

Install Aeration;

Install Filtration;

Chemical Control

Residual Risk Factor

(Table 4) <5

Considered to be


If BGA & [P]

Blooms Start

Page 24 of 64

Jan 2013

BLUE GREEN ALGAE CONTROL

Residual Risk Factor

(Table 4) <5

Considered to be Low

No Action Planned


If BGA & [P] Increase or

Blooms Start to Form



Review 31 Jan 2013

4.1 INDIVIDUAL WASTE WATER TREATMENT PLANT DETAILS:

A history of all blooms occurring over a three year term for each plant is to be

prepared/updated by the plant operator and provided to the regional coordinator by August

31st each year. This history is to include the following information (See attached form

Appendix D) and is to be used to determine preventative and control actions for each plant

ahead of the forthcoming BGA bloom season. Hard copy of the history is to be maintained at

the relevant BLW depot and an electronic copy is to be maintained by each area coordinator.

• Facility name;

• Affected components of the system (lagoons);

• The seasonality and longevity of blooms;

• Species present;

o Results of cell density; and

o Toxicity testing results.

• Operational responses initiated;

• Controls applied;

• Details of downstream water users;

• Contact telephone numbers of downstream users;

4.2 AVAILABLE ACTIONS:

A number of pre-emptive actions (Operational responses) are available that may assist in the

prevention of BGA colonisation and/or bloom formation. In addition if prevention is not

successful, there are further actions that may then be undertaken to control or limit the

expansion of blooms or their spread to other lagoons or receiving water bodies.

4.2.1 BLOOM PREVENTION:

Actions taken to prevent the formation of blooms require significant forward planning and

expenditure to undertake, they include:

• Removal of sludge to reduce in situ sources of N & P;

• Use of agitators and aeration to promote vertical mixing and to break up any thermo-

cline. This will assist in preventing sediments from becoming anoxic and their release

of nutrients to the water column;

• Reduction of external inputs of N and P to the facility;

• Fixation of N & P within the sediments (e.g. use of ferric hydroxide “Phoslock” etc);

• Isolation of lagoons with a known BGA history; and

• Management of residence time within the system.



Review 31 Jan 2013

4.2.2 CONTROLLING DEVELOPED BLOOMS

Once BGA blooms have formed the ability to discharge to the normal plant discharge point

will be governed by the cell count of the bloom and its toxin content. Options to remove

blooms at this point are limited to chemical action such as dosing with ferric chloride or other

substance capable of removing phosphate from the water column and locking up phosphate

in the sediments. In the absence of available P the bloom may collapse. At this point there is

a danger that toxins may be released from decomposing algae into the water column.

Management through chemical means is both expensive and potentially counter-productive

once a bloom has formed. Other options responding to bloom formation include use of

emergency irrigation, the isolation of affected lagoons and use of mechanical methods to

break up stratification in the lagoons

Methods to control developed blooms include:

• Fixation of N & P within the sediments (e.g. use of ferric hydroxide “Phoslock” etc);

• **Emergency Irrigation of affected water;

• **Isolation of affected lagoon/s;

• Physical removal of blooms from water column (filtration, screening and plankton

netting);

• Continued Sludge reduction;

• **Controlling depth of outlet to “miss” highest bloom concentrations;

• **Disruption of thermo-cline with agitation and aeration;

• **Use of barley straw bales or other medium for filtration;

• Removal or restriction of external sources of N & P;

• Use of chemical algicides (Least desirable option); and

• **Application of chemical/biological competitors for nutrient supply in the sludge.

NB. Items identified by a ** are options potentially available for the 2011/12 summer/autumn

season.



Review 31 Jan 2013

5 DOCUMENTATION OF CONTROLS, MATERIALS AND METHODS

The primary drivers of blue green algae blooms are high levels of Phosphate [P] in the water

column and sediments, long daylight hours, a stratified water column with heated surface

layers, anoxic sediment conditions and re-cycling of nutrients from the sediments.

5.1 SLUDGE MANAGEMENT

Significant lead times are required to plan for the removal and disposal of sludge from waste

water treatment plant lagoons. Sludge content should be maintained at >10% and <20% of

the volume of a lagoon for ideal operating conditions for lagoons systems. The Ben Lomond

Water Biosolids Management Strategy will provide for the regular harvesting of sludge from

lagoons on a priority basis. The Ben Lomond Biosolids Strategy recognises that nuisance

outbreaks are frequently related to excessive sludge build-up in lagoons and knowledge of

the blue-green algae history of each plant is a significant factor in determining the priorities

for the lagoons de-sludging program. From a operational standpoint integration of the

management of blue-green algae and management of Biosolids build up in lagoons is

essential. Given the high cost of sludge management, planning for sludge removal should

provide a lead time of at least 18 – 24 months a process that will be considerably aided by

access to clear medium term records of the blue-green algae bloom history for each lagoon.

5.2 EMERGENCY IRRIGATION

For emergency irrigation to be undertaken, it is first necessary to establish that no other

control methods are available and in fact the situation does constitute an emergency. In the

event that emergency irrigation is deemed feasible, the EPA will potentially require a form of

DP&EMP to establish where and how the program will take place and what controls will be

placed on the activity.

For the development of a viable emergency irrigation program, a permit will be required and

an agreement will need to be reached with an accepting land-owner. BLW will then need to

ensure that through the undertaking of an irrigation program there is no potential for persons,

agricultural land and the environment to be damaged through the process.

There is also a requirement to source suitable pumps, piping and the means of application.



Review 31 Jan 2013

5.3 MECHANICAL METHODS TO PREVENT OR CONTROL BLOOMS

Stratification of lagoons is common in the summer months. Warmer surface layers tend to

promote the expansion of Blue Green algae blooms while cooler bottom layers beneath a

thermo-cline tend to become anoxic and the anaerobic conditions prevailing at the sludge

surface encourage the release of nutrients bound in the sediments into the water column.

Surface mixers and aerators may be used to break down stratification in the water column

and to ensure that bottom layers are oxygenated such that the upper layers of the sludge

deposit are maintained in an aerobic condition.

Induced vertical mixing interrupts the diurnal rise and fall of BGA in the water column and this

also interferes with the competitiveness and productivity of these species.

If aeration is too energetic, aeration such as that provided by high speed surface mixers, can

damage BGA cells with the potential for the release of toxic compounds into the water

column.

The choice of aerators is a critical factor in terms of overall lagoon performance. The aim is

to break up the thermo-cline but not to re-suspend the sludge layer. A number of options are

available. Ideally an installation providing an upwelling motion leading to a directed surface

flow creating circulation within the lagoon is preferable.

Lower layers may also be oxygenated by the use of bubblers placed on, or suspended just

above, the bottom of the lagoon. The use of bubblers is less effective in breaking up a

thermo-cline and providing full water depth mixing than the use of aerators.

5.4 CHEMICAL METHODS TO PREVENT OR CONTROL BLOOMS

A range of proprietary chemical methods are available for the prevention or control of BGA

Blooms.

These include the use of competitive bacteria e.g. Bio-amp, “For Earth” probiotics, and ETG

Gold; the use of copper-based algicides and the use of bentonite-based treatments e.g.

PHOSLOCK that lock up available phosphate in the water column and form a reactive layer

at the sediment surface that both restricts the release of P from that source and also

continues to sequester P from the water column.

These treatments tend to be expensive, they range from treatments that act to reduce

sludge, that out-compete Blue-Green Algae for resources or that lock up available nutrients

in the water column and in the sludge. They may offer temporary control of algae with repeat

dosing within any one season and in subsequent seasons or may offer a longer-term

solution.



Review 31 Jan 2013

A number of chemical approaches have been trialled elsewhere in Tasmania with varying

results. For example, the Bio-amp system has been trialled by Southern Water and has been

partially effective in controlling BOD but has been less effective in the control of a Euglena

sp., bloom.

The results to date suggest that the bacteria introduced have competed successfully for

nutrient and other resources in the resident sludge but the installation may have too little to

provide for any large–scale or effective control of algae.

On analysis it is not clear therefore whether the trial undertaken was a fair test of the product

or otherwise. Opportunistic or ad hoc trials of this nature are unlikely to be effective in

demonstrating the worth, or otherwise, of any chemical or mechanical approach to control

Blue-Green Algae.

Full-scale in-situ trials should ensure that the controlling agent is applied in sufficient intensity

to manage the problem issue, for example Blue-Green Algae blooms. The alternative is to

conduct scaled down treatments within a carefully structured and controlled experimental

program.

Such an approach, if adopted, has the capacity to provide directly comparable outcomes for

experimental applications for a number of proposed treatments conducted under carefully

controlled experimental conditions.

At present, without more definitive information, chemical approaches have their place in an

emergency but may not be able to replace other management-based solutions such as

appropriate sludge control and the timely deployment of water column agitation and aeration.

5.5 BLUE-GREEN ALGAE BLOOMS – SUMMER 2010/11

During the 2010/11 summer season, Eastern Australia, including Tasmania, was under the

influence of a La Niňa phase of the El Niňo – Southern Oscillation (ENSO) cycle. La Niňa of

2010/11 was the strongest since records began in the early 1800’s. Climatic conditions

associated with the cooling of the western pacific (La Niňa) manifested themselves by cooler

and cloudy conditions over the summer period with significantly greater rainfall than average.

While blue-green algae outbreaks are known to be correlated with warm weather and high

levels of sunlight, the opposite, wet, cooler and cloudy summer conditions, has not been well

documented.

It appears probable that the La Niňa conditions, as well as a higher degree of storm water

inputs to lagoons, may have contributed to the very much reduced incidence of blue-green

algae bloom formation in the majority of BLW lagoons-based system.



Review 31 Jan 2013

As ENSO cycles are now regularly predicted by the Bureau of Meteorology, it should now be

possible to make a reasonable forecast of the probability of blue-green algae bloom

formation for each plant for forthcoming summer seasons.

5.6 BLUE-GREEN ALGAE BLOOMS – SUMMER 2011/12

The Australian Bureau of Meteorology has indicated that La Niňa conditions are likely to

persist in the western Pacific until at least the autumn of 2012. This indicates that a wetter

than average summer season is anticipated that conditions are likely to be similar to the

2010/11 summer season. La Niňa conditions are likely to bring about cooler and cloudy

conditions and these may inhibit the development of blue-green algae blooms until later in

the season.



Review 31 Jan 2013

6 ROUTINE SAMPLING FOR BLUE-GREEN ALGAE.

Routine sampling is to be undertaken on a monthly basis between September and March.

Sampling from all lagoons shall be completed in the first week of the months and the

resulting batch of samples is to be conveyed within Chain of Custody conditions to an

appropriate NATA certified laboratory for counting and potential toxin analysis.

6.1 REPRESENTATIVE BLOOM SAMPLING

The aim of representative sampling is to determine the ambient concentration of Blue-Green

Algae cells within a water body and to inform any response actions.

For accurate and representative sampling, it is important to recognise that the concentration

of Blue Green Algae at the surface of a water body is dependent upon a number of

environmental factors including the time of day, the temperature, sunny and windy

conditions.

Typically a green scum may form at the water surface of a lagoon early in the day or in the

evening but may not be present during the bright part of the day. In addition this scum may

drift to one corner or side of the facility. This temporal and spatially variability of surface

blooms clearly makes decisions on when and where to sample algae critical and may have

profound effects on the numerical estimates of algae present within any particular system.

Blue-Green Algae are naturally buoyant as they contain gas in specialised gas vesicles

within the cellular structure. Along with all other green plants Blue-Green Algae produce

carbohydrates through the process of photosynthesis. The product of photosynthesis is the

production of sugars (carbohydrates). Algal cells in bright sunlight at the surface tend to “load

up” with carbohydrate and (as they gain weight) they tend to then sink within the water body.

Once out of the sunlight, production of carbohydrates slows and ceases and respiration and

cell reproduction together consumes the sugars (the algae essentially lose weight!). The

algae then respond to gas held within specialist gas vesicles within the cells and become

buoyant and rise up again into the sunlight near the surface. This is the process that

produces the scum often seen on the surface early in the day and also accounts for the

diminished levels of algae seen at the surface in the bright part of the day.

Given this knowledge it is thus essential to undertake sampling at the same time of day every

time that a sample is obtained. In addition it is important to recognise that samples should be

taken wherever possible away from the edges of a water body, away from any windrows or

drift, in a position that is more representative of ambient conditions within the water body.



Review 31 Jan 2013

6.2 SAMPLING TO CHARACTERISE SPECIES PRESENT AND TOXICITY

Where sampling is required to determine the species present within a bloom and the

potentiality for toxic species to be present, then it may be appropriate to sample from a scum

layer or windrow.

The condition of the algae within a scum layer may denote algal health, for example the

scum may be algae rising to the surface early in the day, or a raft of dead algae.

Sampling of dead algae may, under some circumstances, give rise to higher levels of toxicity

as cells break down and release their toxic contents, than toxicity indicated from cells

sampled in open water. The ultimate level of toxicity will be a function of cell numbers, the

toxicity of a sample and the condition of cells within the sample.

Clearly great care is required when undertaking routine sampling and when undertaking

response sampling for Blue-Green Algae and for estimation of toxicity.

6.3 METHODS FOR SAMPLING

Ideally representative sampling should be done from a boat. This is however clearly

impractical under most circumstances.

In all cases of sampling from a particular system, sampling should be undertaken at the

same time of day. Ideally sampling should be first thing in the morning with the actual time

recorded.

6.3.1 SAMPLING AT AN OUTFALL

Samples may be collected at a defined depth in an outfall pit or where the effluent leaves the

plant and enters the environment. This will allow an estimation of the Blue-Green Algae

loading entering the receiving water body.



Review 31 Jan 2013

6.3.2 SAMPLING WITHIN A BODY OF WATER

The aim is to obtain a representative sample of Blue-Green Algae from within a water

column. It is not to obtain maximum counts from a scum of bloom on the surface. Sampling

of the water body (lagoon) should be undertaken at a prescribed depth with multiple samples

from different parts of a lagoon. Samples may then be analysed separately or they may be

pooled. Where samples are to be pooled they should be of equal volume to ensure a bias in

the results does not occur. Sampling within the water body will provide a reliable estimate of

the density of cells within a lagoon.

Ben Lomond Water will standardise water body sampling using a sampling pole and

obtaining 5 samples at 500mm depth at each of 2 sites in each lagoon and compositing

these and then sub-sampling from the composite. This sample will then be representative of

the Blue-Green Algae count for open water in that lagoon.

Other methods for sampling may be employed. Samples may be obtained using a sampling

pole or may be pumped from below the surface and may be taken from a fixed depth or may

be stratified to sample above or below the thermocline.




6.4 TRIGGER LEVELS

A Detection, and three (3) levels of Alert with appropriate response activities, are provided by

Burch et al. (2005) for lagoons and were reproduced in the Tasmanian EPA’s BGA Sampling

Strategy Decision Tree (Table 5, below).

Alert Level Alert Criteria Response

Detection

Level

<2,000 cells/ml total BGA • Continue monitoring on

a monthly basis

depending on the

history of blooms

within the lagoon

system.

<2,000 – 11,500 cells/ml total BGA with: < 5,000

cells/ml of known toxic sp and <0.4mm3 bio-

volume total BGA

Alert Level 1 2,000 – 11,500 cell/ml total BGA : < 5,000

cells/ml of known toxic species and 0.4 – 4.0 mm3

bio-volume total BGA

• Monitor outfall weekly.

• Implement

mitigation/managemen

t strategies. > 11,500 cell/ml total BGA : < 5,000

cells/ml of known toxic species and 0.4 mm3 bio-

volume total BGA

Alert Level 2 2,000 – 11,500 cell/ml total BGA with <5,000

cells/ml of known toxic species and >4.0 mm3 bio-

volume total BGA

• Monitor outfall weekly.

• Implement

mitigation/managemen

t strategies.

• Contact Environmental

Health Officers (EHO’s)

& the EPA

2,000 – 11,500 cell/ml total BGA with >5,000

cells/ml of known toxic species.

> 11,500 cell/ml total BGA with <5,000 cells/ml

of known toxic species and <4-10mm> bio-volume

BGA

> 11,500 cell/ml total BGA with >5,000 cells/ml

of known toxic species tested to be non-toxic.

Alert Level 3 > 11,500 cell/ml total BGA with <5,000 cells/ml of

known toxic species and >10mm3 bio-volume total

BGA

• Monitor outfall &

lagoons weekly.

• Implement Contingency

management strategies

for discharge/reuse.

• Contact EHO & EPA

• Initiate NATA toxin

testing.

11,500 cell/ml total BGA with >5,000 cells/ml of

known toxic species

> 11,500 cells/ml total BGA with >5,000 cells/ml

of known toxic species tested to be toxic.

Table 5 Tasmanian EPA Sampling Alert and Response Protocol

The data presented in Table 5 recognises that species of Blue-Green Algae known to be

toxic under one range of environmental conditions may not necessarily develop toxicity under

a different set of conditions.




For recreational use waters, the NH&MRC provides the following three trigger levels:

• Low numbers <2,000 cells/ml;

• Moderate numbers >2,000 to <11,500 cell/ml; and

• High numbers >11,500 cells.

Similarly the NH&MRC also provides trigger levels for irrigation of reuse wastewater (Table

6).

6.4.1 SAMPLING RESULTS AND TRIGGER VALUES

Following the sample collection, positive presence and identification of BGA (as discussed in

sections 6.2 and 6.3), analytical results should be compared to the relevant guidelines or

trigger values. Most of the level 2 waste water treatment plants that have EPNs contain

specific maximum allowable levels of BGA. Therefore, individual plant EPN conditions should

be checked prior to comparing results against the trigger levels provided in Table 5. If BGA is

present then the Blue Green Algae Control Program (refer Figure 3) should be followed.




Reuse

Class

Example Reuse options Risk Microcystin Alert

level

Anabaena Alert Level Comments

Cell no Toxin Cell no Toxin

A • Groundwater recharge. Non-potable

municipal irrigation

• Fire & water protection systems

• Direct Contact with crops consumed

raw

• Urban use (garden watering and

toilets)

• Agriculture

Low to

high

5,000

cells/ml

- 15,000 cells/ml - • No spray drift

• Limits reached over 2

consecutive readings

• 5 day withholding period for

grazing

• 4 hr withholding period for

public access

• No groundwater recharge

B • Indirect contact with crops to be

consumed raw

• Pasture and fodder (withholding

applies)

• Industrial processes

• Non-potable municipal irrigation with

controlled access

Low to

med

50,000

cells/ml

10mg/L 1000,000 cells/ml 20 mg/L • No spray drift

• 5 day withholding period for

grazing


public access

C • Non-human food chain agriculture

(e.g. forestry)

• Industrial processes

• Non human food chain aquaculture

Low 50,000

cells/ml

10 mg/l 100,000 cells/ml 20 mg/L • No spray drift


public access

Table 6 NH&MRC Suggested trigger levels for irrigation of reuse waste water.




6.5 RESPONSIBILITIES

A clear allocation of tasks identifying units/staff accountable for this and including a timeline

will be required to progress the BLW Management Plan for Blue Green Algae as set out

below.

A component of this is the evaluation of the risk of BGA bloom formation and the formulation

of response mechanisms. This will require close cooperation between Operational Services

staff and staff in Assets where a CAPEX requirement for infrastructure to control blooms is

identified.

6.5.1 EXECUTIVE MANAGER SERVICE DELIVERY

The sustainable operation of lagoon systems is the responsibility of the Executive Manager,

Operations.

It is the responsibility of the Executive Manager, Service Delivery to prepare a budget for BGA

management, including a budget for bio-solids management, at least 12 months ahead of the

next summer season.

Planning for sludge removal to assist in the reduction of bloom formation will require a lead

time of at least 18-24 months. This is to allow for appropriate planning for the methodology of

removal, the securing of environmental approvals, arrangements for the disposal of this

material and the allocation of the financial resources required carry-out this work.

6.5.2 REGIONAL MANAGERS AND WASTE WATER MANAGER

It is the responsibility of the Regional Managers to maintain a monitoring program for lagoons

including: monthly sampling for BGA between September and March; the regular profiling of

lagoons to determine sludge build up; and the condition of lagoons with respect to the

availability of water nutrients N and P.

An assessment of the potential for bloom formation for each lagoons system may be

determined from past seasons history and the immediate past summer season. Where

infrastructure is required, this needs to be identified prior to the development of the CAPEX

program for the following year and in any event will be required by mid-winter to allow for the

effective application of control measures ahead of the forthcoming spring, summer and

autumn seasons.




6.5.3 COORDINATORS AND PLANT OPERATORS

A responsibility of operational staff is to provide management with timely information relating

as to the status of sludge within lagoons and the presence, and development of BGA

infestations within lagoons systems.

It is the responsibility of Plant Operators and their Coordinators to implement the management

program and aspects of BGA management as directed by the Executive Manager or

delegated to Managers and Coordinators.




7 INDIVIDUAL ACTION PLANS

Individual Blue Green Algae Action Plans are drawn up for waste water treatment plants

requiring works. These plants are:

• Prospect Vale;

• Scamander;

• Bridport;

• Westbury;

• Carrick;

• Longford;

• Beaconsfield;

• Deloraine; and

• Evandale

Among these plants there are a number that have no immediately viable potential for the use

of emergency irrigation as a disposal means for BGA contaminated effluent, these plants

include: Beaconsfield and Prospect Vale. Previous emergency irrigation has been employed

at Carrick and Longford. Reasonable potential exists for emergency irrigation at Westbury.

This situation, together with the status of the Level 1 plants is set out in Appendix B.

7.1 ACTION PLANS - GENERAL

A generic emergency irrigation strategy will be prepared for negotiation with the EPA. It is

intended that this Action Plan will be available to be tailored for individual plants.

For identified plants where a BGA problem may be anticipated and land for irrigation may be

available, preliminary negotiations with the landowners will be entered into to develop a

potential emergency irrigation site.

Contingency plans are also to be prepared for each lagoon system potentially at risk for BGA

bloom formation, plans to include:

• An assessment of the reticulated capability of each potentially affected WWTP for the

isolation of individual lagoons within the WWTP system;

• An assessment of the capability for the deployment of multiple directional aerators at

each plant;

• An agreed framework document (between BLW and local land-owners) to provide for

emergency irrigation at each plant potentially at risk of BGA bloom formation; and

• An internal framework for access to sufficient financial resources to support a required

remedial program to manage BGA blooms.




APPENDIX A BLUE GREEN ALGAE BLOOMS, WATER NUTRIENTS AND SLUDGE

STATUS INFORMATION




Appendix A Ben Lomond Water Plants that Utilise lagoons as Part of the Process.

Plant Jan-10 Jun-10 History

No of

Lagoons

BGA Feb

10

BGA FEB

11 Irrigation Sludge

TP TN TP TN

Yrs in

Bloom Affected

cells/ml

cells/ml Comment Scheme max %

Campbell Town 5.8 13 6.86 11.6 Yes 37%

Cressy 7.8 12 5.28 7.58 830,000 3,045,300 Yes 18%

Evandale 9.8 18 9.8 26.1 10,000,000 220,000 Yes 34%

Perth 9.4 17 8.31 23.1 2,300,000 66,800 Yes 16%

Carrick 12 7.2 3.38 9.4 4+ years

Large

lagoon 280,000 N/D IDEALs No No data

Deloraine 7.9 6.7 4.7 12.9 4 years+ L 2 28,000 2,400,000 IDEALs No 59%

Bridport 10.7 33 10.6 44 4 yrs + 1 & 2 31,800 N/D Golf 57%

St Helens 0.03 4.2 0.18 4.26 1 year 1 & 2 minor N/D plant recycling via L's No 20%

Stieglitz 10 5.5 12.5 5.5

some

years minor 2,500,000 Yes 25%

Scamander 4.1 5.4 19.6 47.8 4 yrs + 2, 3, & 4 4,000,000 6,602,910 l's 2 & 4 worst. Golf No data

St Marys 6.2 12 5.84 11.5 4 yrs + On farm 280,000 48,000 Polishing & Salters L's Yes 45%

Fingal 7 17 5.53 21 4 yrs + Facultative 27,000 N/D No No data

George Town 3.8 4.9 2.82 9.7 N/D aerated cells No No Data

Westbury 0.13 3.2 0.26 1.77 every yr L 1 & 2 3,000,000 N/D DAF Plant off-line over summer 30%

Longford 8.5 50 13.6 40.3 minor L's 5 & 6 N/D L's 5 & 6 aerated No 67%

Lilydale 2.2 5.8 3.21 29 4+ yrs all lagoons 4,300,000 N/D Yes No Data

Prospect Vale 14.5 35 8.94 32

4+ yrs

L4,

2009 L 2,3

&4 136,000 N/D IDEALs No 44%

Legana 8.3 9.48 34 4 yrs + 1 & 2 4,900,000 1,000,000 System overloaded? Yes 30%

Exeter 6.6 9.75 28 4 yrs + 1 & 2 461,000 15,000 Yes 26%

Beauty point 1.99 8.58 25 4 yrs + 1, 2, 3, & 4 252,000 56,000 Yes 28%

Beaconsfield. 2.4 10.7 8.23 23 4 yrs + 1 1,200,000 16,000 irrigation scheme planned No 29%

[TP] > 5 mg/l in red Plants with a level of nutrient management




APPENDIX B EMERGENCY IRRIGATION OPPORTUNITIES




Emergency Irrigation Opportunities

Waste Water Treatment Plant Emergency Irrigation

Undertaken Previously

Potential for Emergency

Irrigation

Level 1 Plants

Ross No Possible

Kalangado No No

Nile No Land Disposal

Western Junction No Possible

Level 2 Plants

Prospect Vale No Possible

Carrick Yes Yes

Westbury No Possible

Deloraine No Possible

Beaconsfield No Irrigation scheme planned

Fingal No No

Longford Yes Yes

Appendix B Plants that cannot be managed by installed irrigation capacity




APPENDIX C 2011-12 - INDIVIDUAL PLANT ACTION SHEETS




Prospect Vale

Blue-Green Algae blooms are a persistent problem at the Prospect Vale Waste Water Treatment

Plant. The BLW Risk Assessment Process identified Prospect Vale as an inherent high risk to the

business, the environment and the community from BGA bloom formation.

The BGA bloom history, nutrient status, sludge content and potential for irrigation for Prospect

Vale is provided in the table below.


No of

Lagoons

BGA FEB


TP TN TP TN

Yrs in

Bloom Affected cells/ml Comment Scheme max %

Prospect

Vale 14.5 35 8.94 32

4+ yrs

L4,

2009 L

2,3 &4 136,000 IDEALs No 44%

Prospect Vale is most at risk on account of a lack of any alternative discharge option. It is

recognised that the availability of irrigation provides significant mitigation against the risks

associated with BGA blooms. Whilst reuse irrigation opportunities are currently being

investigated, Prospect Vale has no immediately viable potential for the use of emergency

irrigation as a disposal means for BGA contaminated effluent.

The establishment of an emergency irrigation program to manage Blue-Green Algae blooms

would require regulatory approval in the form of a DP&EMP, an agreement with a local land

owner to accept the waste and for the establishment, or the provision, of suitable pumps, pipes

and irrigation equipment.

During the 2010/2011 summer, two lagoons were taken off line resulting in reducing the retention

time of the effluent. This approach was likely responsible for reducing the likelihood of BGA

blooms and will utilised as required.




Proposed Actions

The program to control blooms for 2011/12 comprises the following recommended actions, these

are set out in order of priority:

Priority Action Target Dates

1 Monitor for presence of blue green algae (and toxicity as

required)

Monthly sampling between

September and March

2 Where blue green algae are identified, isolate lagoon 1,

re-direct overflow from screens to lagoon 2. This will

reduce the residence time of effluent passing through

the lagoons system to <50 days

As required

3 If action 2 is not sufficient in managing the levels of blue

green algae, negotiate with EPA and land-holders for an

emergency irrigation permit

4 Prioritise sludge removal from lagoons and make

provision for bio-solids disposal

October 30 2012

5 Evaluate power requirements for additional aeration or

agitation of lagoons

6 Evaluate options for chemical controls including a

research based approach on bloom formation and on

sludge reduction/maintenance. The addition of ETG Gold

to lagoons will be undertaken during the 2011/2012

summer

Commenced Summer 2010/11

7 Re-survey lagoon sludge depths




Scamander

There is a high probability of Blue-Green Algae blooms forming and becoming a persistent

problem at the Scamander Waste Water Treatment Plant. The BLW Risk Assessment Process

identified Scamander as an inherent high risk to the business, the environment and the

community from BGA bloom formation. At Scamander the principal driver is the long residence

time of water within the system, in particular in the re-use water storage lagoon. Scamander is

entirely reliant on irrigating a golf course with the only alternative discharge being to a barred

estuary

The BGA bloom history, nutrient status, sludge content and potential for irrigation for Scamander

is shown below.


No of

Lagoons

BGA FEB


TP TN TP TN

Yrs in


Scamander 4.1 5.4 13.3 10.4

4+ yrs

L4, 2009 L 4 10,000,000

In Re-use

storage Golf Club ~10%

Proposed Actions





required)

Monthly sampling

between September and

March

2 Abide by Department of Health and Human Services advisory

with respect to irrigation timing and restrictions of access

following irrigation of golf club fairways.

3 Reduce the residence time of effluent passing through the

lagoons system to <35 days. This may be achieved by taking

lagoons off-line.

4 Evaluate the available electrical supply to allow for the

installation of aerators or other agitation devices into the re-

use storage lagoon to disrupt development of a thermocline.

In Progress

5 Investigate additional sites for emergency irrigation.

6 Commence negotiations for an effective outlet for wet

weather discharges.

7 Fully evaluate the most effective means of providing agitation

within the re-use storage dam.

8 Expedite CAPEX process to acquire the appropriate

infrastructure for this purpose.




Longford

There is a high potential for Blue-Green Algae bloom formation at the Longford Waste Water

Treatment Plant. Over past years this has been successfully managed by installed aeration

capacity and moderate effluent residence times. Opportunities for emergency irrigation at

Longford have been available in past years and have received acceptance from land-owners and

approval from the regulators.

The BGA bloom history, nutrient status, sludge content and potential for irrigation for Longford is

shown below.


No of

Lagoons

BGA FEB


TP TN TP TN

Yrs in


Longford 8.5 50 14.4 66.1 4+ yrs,

2009 L 5

& 6 N/D No 67%

Proposed Actions





required).

Monthly sampling


March

2 Plan for sludge removal from lagoons and make provision for

bio-solids disposal.

In Progress

3 Prepare contingency plans for isolation of infected lagoons as

required.

4 Prepare contingency plans for emergency irrigation is

acceptable or feasible.

5 Maintain aeration/agitation in maturation lagoons.




Bridport

Blue-Green Algae blooms are a persistent problem at the Bridport Waste Water Treatment Plant.

Bridport relies on seasonal golf course discharge but otherwise discharges via a broken marine

outfall. Repairs of the outfall are estimated at several million dollars and the EPA have suggested

evaluating an option of dune percolation disposal.

Installation of a Bioamp system to the main Bridport pumping station immediately downstream of

lagoons occurred in May 2011 and the performance of this system will be monitored over the

2011/12 summer season.

The BGA bloom history, nutrient status, sludge content and potential for irrigation for Bridport is

shown below.


No of

Lagoons

BGA FEB


TP TN TP TN

Yrs in


Bridport ND ND ND ND 4+ yrs,

2009 L

1, 2 &3 31,800

In all

lagoons Golf Club >45%

Proposed Actions





required).

Monthly sampling


March

2 Expedite a sludge management program for Bridport including

disposal of bio-solids onto farm land.

December 30 2011

3 Negotiate with the golf club to take additional treated water.

4 Abide by Department of Health and Human Services advisory

with respect to irrigation timing and restrictions of access

following irrigation of golf club fairways.

As required

5 Plan to undertake a controlled evaluation of a proprietary

biological/chemical Blue-Green Algae control process. (A

bioamp was installed at the main Bridport sewage pumping

station in early 2011).

Monitor performance of

bioamp over summer

2011/2012

6 Evaluate the capability of the wind generator electrical supply

system to power aeration or other agitation devices in the

lagoons.

7 Evaluate alternative wind or solar-powered aerator devices

e.g. Solarbee.

8 Negotiate for additional sites for emergency irrigation.

9 Evaluate dune percolation disposal option versus a repaired

marine outfall.

2011/2012




Beaconsfield

Blue-Green Algae blooms are a persistent problem at the Beaconsfield Waste Water Treatment

Plant. Until recently Beaconsfield did not have any emergency irrigation opportunities. BLW is

now in the process of acquiring land at Whites Road, Beaconsfield upon which to establish a

plantation-based effluent reuse scheme. It is envisaged that this scheme will be commissioned in

the second quarter of 2012. In the interim, however a potential exists to utilise this land for a

emergency reuse opportunity.

The BGA bloom history, nutrient status, sludge content and potential for irrigation for

Beaconsfield is shown below.


No of

Lagoons

BGA FEB


TP TN TP TN

Yrs in


Beaconsfield 8.23 23 1.99 N/D 4+ yrs,

2009 L

1, & 2 1,200,000

In all

lagoons

No

Scheme 29%

Proposed Actions





required).

Monthly sampling


March

2 Ensure that lagoons are drawn down by late winter to take

advantage of higher winter flows in Brandy Creek. This will

allow for some additional storage capacity over the dryer

months.

3 Evaluate options for potential emergency irrigation sites on

adjacent farmland.

Negotiations and planning

for the development of a

plantation reuse scheme

are advanced and it is

hoped to commence work

on this in January 2012. If

this scheme proceeds it is

planned to abandon the

wetlands.

4 Evaluate options for a sludge management program and bio-

solids disposal onto farm land.

5 Evaluate opportunity for Biological/Chemical controls.

6 Evaluate the capability of the electrical supply system to

power aeration or other agitation devices in the lagoons.

7 Investigate the potential to re-commission the on-site wet-

lands system.

;

;




Evandale

Blue-Green Algae blooms are a persistent problem at the Evandale Waste Water Treatment

Plant.

BLW have recently undertaken discussions with a farmer for the commencement of reuse

irrigation and storage. As of November 2011, the farmer has been undertaking reuse irrigation.

The BGA bloom history, nutrient status, sludge content and potential for irrigation for Evandale is

shown below.

Plant Jan-10 Jun-10 History No of

Lagoons

Affected

BGA FEB

10

Irrigation

Scheme

Sludge

max % TP TN TP TN

Yrs in

Bloom cells/ml Comment

Evandale 18 9.8 9.8 26.1 4+ yrs,

2009 L,s1

& 2 & re-

use 10,000,000

Final

lagoons

Full

Re-use 35%

Proposed Actions





required).

Monthly sampling


March

2 Ensure that lagoons are drawn down by late winter to provide

maximum storage capacity for the dryer months.

3 Plan to undertake sludge removal at Evandale and disposal of

bio-solids onto farm land.

2012-2013


power aeration or other agitation devices in affected lagoons.

5 Consider enlarging the rising main to the re-use storage dam.




Deloraine

Blue-Green Algae blooms are a moderate problem at the Deloraine Waste Water Treatment

Plant. Emergency irrigation has not been undertaken previously at Deloraine however BLW are

holding discussions with farmers on adjacent properties for future emergency requirements. BLW

have considered investigating controlled discharge to increase storage capacity however, this

option is not practical.

The BGA bloom history, nutrient status, sludge content and potential for irrigation for Deloraine is

shown below.


No of

Lagoons

BGA FEB


TP TN TP TN

Yrs in


Deloraine 0.127 3.2 4.79 10.5 4+ yrs, 2009 L 2 28,000 None 59%

Proposed Actions





required).

Monthly sampling


March

2 Plan to undertake sludge removal at Deloraine and disposal of

bio-solids onto farm land (Lagoon 2 at 59% capacity)

2012-2014

3 Maintain lagoons at a low level to allow additional capacity for

treated water detention in the event of a bloom forming.

4 Evaluate options for emergency irrigation. In Progress


power aeration or other agitation devices in affected lagoons.




Westbury

Blue-Green Algae blooms are a persistent problem at the Westbury Waste Water Treatment

Plant.

Attention to lagoons management and the operations of the Dissolved Air Flotation (DAF) plant is

expected to manage the threat of BGA bloom formation at Westbury. In addition to this, BLW are

currently investigating reuse opportunities on neighbouring properties. There has not previously

been any emergency irrigation undertaken at Westbury.

The BGA bloom history, nutrient status, sludge content and potential for irrigation for Westbury is

shown below.


No of

Lagoons

BGA FEB


TP TN TP TN

Yrs in


Westbury 0.127 3.2 0.209 18.3 4+ yrs,

2009 L

1, & 2 3,000,000

In all

lagoons

No

Scheme >30%

Proposed Actions





required).

Monthly sampling


March

2 Ensure that lagoons are drawn down by late winter to take

advantage of high winter flows into Quamby Brook. This will

allow storage capacity over the dryer months and take the

pressure off the DAF system.

3 Maintain operations of the DAF and UV sterilisation systems.


neighbouring farmland.

BLW are currently

investigating potential

sites (Nov 2011)


power aeration or other agitation devices in the lagoons.

6 Expedite a sludge management program for Westbury

including disposal of bio-solids onto farm land.




Carrick

Blue-Green Algae blooms are a persistent problem at the Carrick Waste Water Treatment Plant.

Carrick has a partially developed reuse scheme and has previously undertaken emergency

irrigation. BLW are currently investigating further reuse irrigation options.

The BGA bloom history, nutrient status, sludge content and potential for irrigation for Carrick is

shown below.


No of

Lagoons

BGA FEB


TP TN TP TN

Yrs in


Carrick 12.0 7.2 N/D N/D 4+ yrs, 2009 L 1 280,000

In all

lagoons

No

Scheme >30%

Proposed Actions





required).

Monthly sampling


March

2 Ensure that lagoons including the re-use storage dam, are

drawn down by late winter. This will allow storage capacity

over the dryer months and take the pressure off the DAF

system

3 Expedite the provision of a new outfall and associated re-use

scheme for Carrick


neighbouring farmland

BLW are currently

investigating potential

sites (Nov 2011)

5 Expedite a sludge management program for Carrick including

disposal of bio-solids onto farm land


power additional aeration or other agitation devices in the

lagoons




APPENDIX D PLANT SPECIFIC HISTORY SHEET




Plant Name

Year

2010 2011 2012 2013

Lagoons Affected

Bloom commenced

(date)

Bloom collapsed

(date)

Species identified

Cell density

Toxicity results

Operational

responses (early

season)

Controls employed

(following bloom

development)

Downstream users Name Telephone No Date of contact

BLW Operator

Name

Date Signature




APPENDIX E BEN LOMOND WATER BUSINESS MANAGEMENT SYSTEM RISK ASSESSMENT

MATRIX




An assessment of the risks associated the development of Blue Green Algae blooms is made

for each of the eight Consequence Descriptors.

1 Financial

Consequence of Blue Green Algae Bloom

Insignificant. <$100k

Minor >$100k, <$500k

Moderate >$500k, <$2M.

Major >$2M, <$5M

Catastrophic >$5M

Almost Certain Carrick; Bridport; Lilydale; Legana; Exeter; Beauty Point; Beaconsfield

Prospect Vale; Scamander; Westbury;

Likely Deloraine; St Marys; Fingal; Longford

Possible Cressy, Evandale;

Perth; Stieglitz;

Unlikely George Town; Campbell Town; St Helens;

Rare

2 OH&S


Insignificant. First Aid injuries. Superficial injury little treatment. Isolated cases of minor illness

Minor. Minor Injury requiring medical treatment. Isolated serious illness.

Moderate. LTI’s<13 weeks. Severe Injury, widespread minor illness

Major. LTI’s >13 weeks. Severe injury & permanent impairment. Widespread serious illness

Catastrophic. Fatality or permanent disablement. Pandemic >50% staff unable to work

Almost Certain Likely Possible All Plants Unlikely Rare




3 Assets


Insignificant Essentially no damage to assets

Minor Minimal damage but no reduction in performance or efficiency of asset system

Moderate Some damage to asset & corresponding reduction in either system efficiency or performance

Major damage to asset & significant reduction in either system efficiency or performance OR period off-line

Catastrophic Destruction of asset with major period off-line

e.g. ANCOLD scale dam failure

Almost Certain Likely Prospect Vale.

Longford

Possible Fingal

Cressy, Evandale, Perth, St Marys, Westbury, Legana, Exeter, Beauty Point.

Carrick, Deloraine, Scamander, Beaconsfield

Unlikely Campbell Town, St Helens, Stieglitz, George Town, Lilydale.

Bridport

Rare




4 Deterioration in Water Quality and Public Health


Insignificant Exposure, no illness or aesthetic impact on customers

Minor Deterioration in WQ parameters.

Minor exposure unlikely to result in illness, some localized customer aesthetic issues.

Moderate Exposure may result in illness in localized area and/or results in aesthetic impact within localized area

Major Exposure causes confirmed illness within a system

Major aesthetic impact within disinfected supply system

Catastrophic Exposure results in confirmed life threatening/severe illness and/or death to one or more customers

Significant aesthetic impact across a disinfected system

Almost Certain Likely Prospect Vale,

Beaconsfield Scamander

Possible Bridport, St Helens, Longford

Unlikely Campbell Town, Cressy, Evandale, Perth, Carrick, Stieglitz, St Marys, Lilydale, Legana, Exeter, Beauty point

Deloraine, Fingal, Westbury

Rare George Town




5 Service Delivery


Insignificant Isolated customer complaints

Minor Multiple customer complaints

Moderate Service disruption >5hrs disruption for ~5% customers

Major Widespread customer complaints.

Service disruption>24hrs disruption for ~10% customers

Catastrophic >1day loss of supply to >1000 customers.

>8hrs duration to special needs customers.

Almost Certain Likely Prospect Vale,

Scamander

Possible Bridport, St Helens, Longford

Unlikely Campbell Town, Cressy, Evandale, Perth, Carrick, Stieglitz, St Marys, Lilydale, Legana, Exeter, Beauty point

Deloraine, Fingal, Westbury, Beaconsfield

Rare George Town




6 Reputation


Insignificant Of interest to individuals only

Stakeholder indifference

Minor Of interest to local community only

Stakeholder aware of issue.

Moderate Significant -ve local media coverage

-ve national media coverage

Stakeholder actively expressing dissatisfaction

Major Significant national media coverage

Stakeholder alarm or grave concern

Catastrophic Loss of community or stakeholder confidence in organisation

Enraged stakeholder and political intervention

Almost Certain Likely Possible Longford,

Scamander, Prospect Vale

Unlikely Campbell Town, Cressy, Evandale, Perth, Carrick, Stieglitz, St Marys, Lilydale, Legana, Exeter, Beauty Point, Fingal, Beaconsfield, Bridport

Deloraine, Westbury, St Helens

Rare




7 Environment


Insignificant Low environmental impact

Minor cleanup/re-instatement required

Minor Localised environmental impact.

Cleanup/re-instatement required

Moderate Moderate environmental impact relating to statutory requirements, short recovery period (weeks)

Required to inform regulatory body.

Major Moderate environmental impact which requires extended recovery period (Months)


Catastrophic Environmental incident resulting in widespread long term damage, long recovery period (years)


Almost Certain Likely Possible Longford Scamander,

Prospect Vale

Unlikely Campbell Town, Cressy, Evandale, Perth, Carrick, St Marys, Lilydale, Legana, Exeter, Beauty Point, Fingal, Bridport

Stieglitz, Beaconsfield, Deloraine, Westbury

St Helens

Rare George Town




8 Compliance


Insignificant Technical compliance breach with limited material impact

Minor Compliance breach may result in minor corrective action or business requirement.

Moderate Penalties for breaches

Third party claims

(e.g. a fine of 250 penalty points for a body corporate)

Major Severe fines for breaches

Multiple third party claims

E.g. a fine of 1000 penalty points for a body corporate.

Catastrophic Loss of charter to operate

Prison sentence for Directors and Operators

Almost Certain Likely Possible Longford,

Beaconsfield,

Deloraine,

Westbury

Scamander, Prospect Vale

Unlikely Campbell Town, Cressy, Evandale, Perth, Carrick, St Marys Lilydale Legana Exeter, Beauty Point, Fingal, Bridport

Stieglitz

Rare George Town

appendix k – blue green algae prevention control and ... · blue-green algae management plan blw...

Documents