1

Drinking Water Audit

Report

County: County Clare Date of Audit: 09/07/2015

Plant(s) visited: Drumcliffe (Ennis)

Drinking Water

Treatment Plant

Date of issue of

Audit Report:

15/07/2015

File Reference: DW2014/231

Auditors: Mr Niall Dunne

Ms Michelle Roche

Audit Criteria: • The European Union (Drinking Water) Regulations 2014 (S.I. 122 of 2014).

• The EPA Handbook on the Implementation of the Regulations for Water

Services Authorities for Public Water Supplies (ISBN: 978-1-84095-349-7)

• The recommendations specified in the EPA Drinking Water Report.

• The recommendations in any previous audit reports.

MAIN FINDINGS

i. The Drumcliffe Water treatment plant is maintained and operated to a high standard.

The SCADA system is very detailed and contributes significantly to the operation and

management of the plant. Irish Water should ensure that the best practices at this plant

are replicated in other drinking water plants under the authority of Irish Water.

ii. The wash water supernatant is returned to the head of the works. This has the potential

to re-introduce contaminants to the treatment plant. Irish Water should carry out a full

review of this practice to determine the effects it has on the operation of the plant and to

identify alternatives to returning the supernatant to the head of the work.

iii. The chlorine dosing/monitoring system as currently arranged will not immediately notify

caretakers of a chlorine failure. The dosing/monitoring arrangement should be reviewed

to ensure that a chlorine failure is detected quickly and responded to promptly.

iv. Some alarm levels at the plant were not set to appropriate levels. Irish Water should

conduct a full review of all alarm levels to ensure that potential issues are quickly

detected and promptly brought to the attention of the caretaker.

1. INTRODUCTION

Under the European Union (Drinking Water) Regulations 2014 the Environmental Protection Agency

is the supervisory authority in relation to Irish Water and its role in the provision of public water

supplies. This audit was carried out to assess the performance of Irish Water in providing clean and

wholesome drinking water.

The Drumcliffe (Ennis) treatment plant servers a population of approximately 30,000. The source

consists of two springs. This is a DBO plant, operated by EPS. Treatment consists of pH correction,

coagulation, flocculation, DAF, microfiltration, chlorine disinfection and fluoride treatment.

2

Photographs taken by Niall Dunne during the audit are attached to this report and are referred to in the

text where relevant.

The opening meeting commenced at 10.30 am at the Druncliffe treatment plant. The scope and purpose

of the audit were outlined at the opening meeting. The audit process consisted of interviews with staff,

review of records and observations made during an inspection of the treatment plant. The audits

observations and recommendations are listed in Section 2 and 4 of this report. The following were in

attendance during the audit.

Representing Irish Water/ County Council/EPS:

Deirdre O Loughlin; Compliance Analyst - Irish Water.

John Fitzgerald; DBO Engineer - Irish Water.

Anthony Mc Namara; Senior Executive Engineer - Clare County Council.

Maura Mc Nulty; Executive Scientist - Clare County Council.

John Strand; Engineer - Clare County Council.

Glen Bain; Operation Supervisor - EPS.

Representing the Environmental Protection Agency:

Michelle Roche – Inspector.

Niall Dunne – Inspector.

2. AUDIT OBSERVATIONS

The audit process is a random sample on a particular day of a facility's operation. Where an

observation or recommendation against a particular issue has not been reported, this should not be

construed to mean that this issue is fully addressed.

1. Source Protection

a. Clare County Council (CCC) has responsibility over the catchment. CCC stated that no recent

catchment surveys have been carried out. CCC is currently in the process of identifying farmers

within the catchment. Once farmers are identified, CCC proposes to distribute GAP and pesticide

information to the farmers.

b. The source for this supply consists of two adjacent springs. The springs were covered, the covers

were not adequate to prevent vermin access (see photograph 1).

c. The Cryptosporidium risk score for this source was calculated as 77, high risk.

d. CCC stated that there is a large zone of contribution relating to the springs.

e. EPS stated that the raw water quality is very variable and weather dependant.

f. The raw water is monitored four times a year by EPA as part of the ground water monitoring

programme, CCC monitor it once a month and EPS monitor it daily but take three yearly audit

samples. According to EPS their sampling programme does not include MCPA.

g. The following parameters are monitored for in the raw water, the results at the time of the audit are

also shown, Oxidation Reduction Potential (ORP) 564 mv; pH 7.6; turbidity 0.43 NTU; colour

13.31 Hazen and conductivity 470 µScm-1

. The respective low and high alarms are ORP 100 & 800

mv; pH 6.5 & 9; colour 45 Hazen, conductivity 900 µScm-1

and turbidity is not alarmed.

h. The following parameters in the raw water are manually monitored on a daily basis pH, true colour,

turbidity, fluoride, iron and manganese.

i. CCC stated that alkalinity of the water can be high, and calcification of pipes is an issue.

j. According to EPS approximately 14,300 m3/day is abstracted.

k. One of the pumps at the source was out of operation at the time of the audit.

3

2. Coagulation, Flocculation

a. EPS stated that the coagulant dosing is based on colour and flow; pH control is based on colour.

Below 45 Hazen the pH is automatically adjusted to 6.7; above 45 Hazen it is adjusted to 6.2. EPS

stated that caretaker gets an alarm if colour goes above 45 Hazen.

b. The aluminium sulphate coagulant is dosed through duty and standby pumps, which automatically

switch over every 12 hours. Prior to the flocculation tanks pH is corrected using Sulphuric Acid

96%.

c. The coagulation process consists of three flocculation tanks. To assist with flocculation and particle

removal a DAF tank is located in series after tank 2 and before tank 3. There is a turbidity monitor

on the return from the DAF plant, which at the time of the audit was reading 0.97 NTU. EPS stated

that the alarm on this turbidity monitor is set at 10 NTU.

d. Algal growth was observed on the walls of the DAF plant and the flocculation tanks (see photograph

2). EPS stated that the DAF plant is cleaned twice a year and was last cleaned in February 2015.

e. EPS approximated that the retention time over the entire flocculation process was 15 minutes.

3. Filtration

a. Filtration consists of membrane filtration. There are six banks of filters with 102 filters in each bank,

612 filters in total. EPS stated that the design capacity of the plant is 18,300 m3/day.

b. The following parameters are measured across each bank of filters, flow (m3/hr); TMP (trans

membrane pressure) (kPa), a pressure decay test (PDT) and resistance.

c. PDT, which is monitored automatically on each bank of filters, is an indicator of the performance of

the membrane filters. EPS stated that if PDT is greater than 20 kPa/min then the log reduction of

Cryptosporidium drops below 5 log removal. According to EPS the PDT alarm is set at 20 kPa/min.

The plant is set to auto shut down when the PDT is greater than 22 kPa/min. EPS stated that when

the PDT is in the region of 17 kPa/min within a bank of filters, then that bank of filters is taken out

of service and a sonic tests on each individual filter cell is undertaken. This procedure is not

documented.

d. Filter back wash cycle is initiated on low colour every 28 minutes and every 22-25 minutes on high

colour. A backwash cycle is also triggered on PDT and resistance across the filters. There is no

alarm on resistance. The back wash cycle lasts approximately 6 minutes. According to EPS, the

resistance target value is 5 and the plant shuts down when the resistance goes above 10. This

procedure is not documented.

e. The filters are also chemically cleaned in place (CIP), every two months with sulphuric acid and

chlorine and every three months with citric acid and chlorine. The wash water following the

chemical cleaning is transferred to a neutralisation tank.

4. Washwater and Picket Fence Thickener

a. Water from the neutralisation tank, the membrane back wash water cycle and the filter press is sent

to a wash water tank, after which poly is added and then the water is sent to the picket fence

thickener (PFT).

b. The supernatant from the picket fence thickener is then returned to the head of the works, prior to

the flocculation tanks and the membrane filters. There is a turbidity monitor on the supernatant

return water. Daily manual monitoring of true and apparent colour and turbidity is carried out.

c. EPS stated that the alarm on the online supernatant turbidity monitor is set at 50 NTU and that the

filtrate factor is adjusted manually when the turbidity on the supernatant return goes above 15-20

NTU. The alum dose automatically adjusts based on the filtrate factor.

d. The supernatant return is not monitored for Crypto, TOC or E.coli.

e. Sludge from the PFT can be diverted to the sludge holding tank or to the filter press.

5. Chlorine and Disinfection

a. Chlorine is dosed via duty standby pumps, and the reading on the chlorine monitor at the time of the

audit was 0.37 mg/l. The chlorine set point is 0.4mg/l.

b. The dosing point for the chlorine is prior to the reservoirs and the sampling point is after the

reservoirs.

4

c. The chlorine alarm is set at 0.25mg/l, the plant does not shut down on low chlorine alarm. EPS

stated that a flow switch is required on the chlorine dosing lines, to detect if dosing stops, as a

malfunction of the chlorination system currently would not be immediately detected.

d. According to CCC chlorine levels at the extremities of the network can be as low as 0.05 mg/l.

Chlorine monitoring results from the network were not available at the time of the audit. CCC said

that chlorine readings within the network are taken on a weekly basis.

6. Treated Water Storage and Distribution Network

a. Treated water is stored in two connected reservoirs. The capacity of each reservoir is 10,000 m3 and

4,545 m3. EPS stated that there is 20 hrs treated water storage capacity within the reservoirs.

b. According to CCC the reservoirs were last cleaned in 2009 and that there are no plans to clean out or

to undertake a condition survey of these reservoirs.

c. Vents were observed on the reservoirs but there was no mesh on them to prevent animal or vermin

access, the covers on the reservoir were also not suitable to prevent surface water ingress and holes

were observed in the covers. At the time of the audit, CCC was unable to open the covers to the

reservoir.

d. There are two reservoirs within the network at Clarecastle, CCC stated that these are scheduled to be

cleaned.

e. IW stated that 205 residents in Ennis are on water restriction notices, and that all consumers with

internal lead plumbing will be notified as per IW lead mailing programme.

f. CCC stated that they propose to remove approximately 1,200 m of cast iron mains in Ennis by the

end of the year.

7. Monitoring and Sampling Programme for treated water

a. On the filtered water there are monitors for pH, turbidity, colour and conductivity.

b. The treated water alarms are set at pH 6.55 (low low) and 8.6 (high high), turbidity 0.2 NTU,

conductivity 800 µScm-1

and colour 7.5 (high) Hazen.

c. The readings on the treated water monitors on the day of audit were turbidity 0.022 NTU,

conductivity 514 µScm-1

.

d. The following parameters are manually monitored on a daily basis, daily results also shown.

Aluminium 0.009 mg/l, pH 6.93, True colour 2 PtCo (Hazen), Apparent colour 2 PtCo (Hazen),

Turbidity 0.08 NTU, Fluoride 0.73 F, Iron 0.01 mg/l, Manganese 0.015 mg/l, free and total chlorine

1.31 and 1.48 mg/l respectively.

e. EPS stated when taking treated water samples this causes a spike in final turbidity readings.

8. Exceedances of the Parametric Values

a. In 2014 there was one iron, three MCPA and six lead exceedances detected in this supply.

b. CCC stated that pesticide leaflets would be issued to all farmers within the catchment.

c. IW stated that they had identified all consumers that are currently on a water restriction. Health

advice will be issue to all consumers with internal lead plumbing as part of the IW lead mailing

programme and that lead would be removed as per the IW lead strategy.

d. CCC stated that they propose to remove 1,200 m of cast iron main within Ennis by the end of 2015.

9. Chemical storage and bunds

a. All chemical tanks were bunded. The fill points for the bulk storage tank were observed to be

outside the bunds (see photograph 3).

b. Chemical levels within the bulk storage tanks are monitored via SCADA. Fluorosilicic acid is

ordered once a month, Aluminium Sulphate and Sodium Hydroxide every six weeks. All chemical

deliveries are supervised and signed off on site.

c. In the pump house located adjacent to the source, there is a sodium hydroxide bulk storage tank and

a potassium permanganate preparation tank (see photograph 4 and 5) which contain chemicals and

used containers of sodium hypochlorite were also observed. According to EPS potassium

permanganate is not dosed, as iron and manganese are not an issue. EPS stated that they were unsure

as to the expiry date or how long the chemicals were in the tanks.

5

10. Hygiene and Housekeeping

a. The hygiene and the housekeeping within the plant is to a high standard.

b. Housekeeping at the pump house and around the source needs to be improved, discarded material

(see photograph 6) and empty chemical containers were observed.

11. Management and Control

a. Security for this site is high and visitors are required to alert site staff prior to entry.

b. EPS stated that the plant runs for 24 hours seven days a week, and that personnel, four site staff, are

on site from 8:00 am - 5:00 pm Monday to Friday. According to EPS there is a 24 hr call out with a

cascade system in operation and the plant can be monitored remotely.

c. EPS stated that staff have not received FETAC training in water treatment.

d. According to EPS all monitors are serviced once a month. In-date calibration stickers were noted on

monitors.

e. Chemical bait boxes were observed outside.

f. EPS stated that chemical spraying is used for weed control at the treatment plant.

13. Sludge Management

a. Sludge (22-23% dry solids) from the sludge press is sent to Lagan concrete.

3. AUDITORS COMMENTS

The Drumcliffe water treatment plant is well run and well maintained. Maintenance of the filters is

regularly and thoroughly undertaken and calibration of the monitoring equipment is regularly carried

out. The SCADA system on site is also very comprehensive, detailing each stage of the process. The

level of management, equipment maintenance and the detail of data available on SCADA should be

replicated by IW at all other treatment works.

The main comment regarding the treatment process is that the supernatant from the picket fence

thickener is returned to the head of the works. This has the potential to re-introduce possible

contaminants into the system, as the supernatant consists of combined water from the neutralisation

tank, the wash water and the filter press. The only online monitor on this supernatant return is a

turbidity monitor, and at the time of the audit the alarm of which was set at 50 NTU, which is

excessively high. The alum dose at the head of the works automatically adjusts based on the filtrate

factor. The filtrate factor, however, has to be manually adjusted based on the turbidity reading from the

supernatant. The alarm on the turbidity monitor should be reviewed and set to an appropriate level. The

adjustment of the filtrate factor should be automated. An investigation into the impact the supernatant

is having on the membrane filtration and the treatment process should be carried out, this should

include a full monitoring analysis of the supernatant to determine its composition and potential to

introduce contaminants. Based on the outcomes of the investigations alternative options instead of

returning the supernatant to the head of the works should be examined. On completion, a report into

this investigation along with any proposed outcomes and timeframes should be submitted to the EPA.

Currently the chlorine dosed point is located prior to and the monitoring point is located after the

reservoir. The reservoir has 20 hours storage capacity. With this current arrangement there is a

potential that a chlorine failure will not be immediately detected. IW must put in place appropriate safe

guards to ensure that any failure of the chlorine system is immediately detected and that the caretakers

quickly alerted.

It was observed during the audit that some of the alarm levels were set very high and would not alert

caretakers within a sufficient timeframe enabling appropriate and timely action. IW should carry out a

full review of all alarm levels at this plant to ensure that they are set to appropriate levels ensuring

caretakers are promptly alerted to any potential hazards.

6

4. RECOMMENDATIONS

Source Protection / Pesticides

1. Irish Water should ensure that;

a. County Clare Council distribute the appropriate advice to farmers within the

catchment regarding the GAP regulations and the use of pesticides/herbcides within

the zone of contribution.

b. MCPA is monitored for in the raw water on a regular basis, especially during periods

of potential use.

c. The use of pesticide/herbicide within the treatment plant site is discontinued.

Distribution Network

2. Irish Water should ensure that ;

a. The correct number of consumers on water restrictions within Ennis is documented

and that this is conveyed to the EPA.

b. The EPA is informed when consumers on this supply with internal lead plumbing

have received appropriate health advice.

c. The proposals for the removal of the cast iron main are continued and that the EPA is

informed when the works are complete, and that follow up iron sampling results are

submitted when works are complete.

Chlorine and Disinfection

3. Irish Water should carry out a full review of the chorine dosing system to ensure that any

failure of the dosing system is quickly detected and that caretakers are promptly alerted. Irish

Water should ensure that the dosing levels are reviewed to ensure that chlorine levels at the

extremities of the network are maintained at 0.1mg/l and are requested to submit two months

chlorine monitoring results from the extremities of the network.

Filtration

4. IW should undertake an investigation into the impact that the PFT supernatant is having on the

membrane filtration and on the treatment process. This investigation should include a full

monitoring analysis on the PFT supernatant to determine its composition and its potential to

introduce contaminants. Based on the outcomes of the investigations, alternative options to

returning the supernatant to the head of the works should be examined so as to reduce the

impact that the supernatant is having on the treatment process.

Management and Control

5. Irish Water should ensure that there is a full review of all the alarm levels to ensure that the

caretakers are promptly notified of elevated readings and of potential failures. The review

should especially include the alarm levels on the turbidity monitor on the supernatant return

and on the PDT. Irish Water should also ensure that the resistance across the membrane filters

and turbidity on the raw water is alarmed and that appropriate alarm levels are set.

6. Irish Water should;

a. Undertake a review of the manual adjustment of the filter factor to determine whether

this process can be automated.

b. Ensure that all the critical procedures relating to the treatment process are reviewed

and that these procedures are documented and target and critical actions levels

defined; for example a sonic review is initiated at 17 kPa/mi PDT, the target

resistance across the filters is 5.

7

c. Investigate treatment options so as to reduce the calcification of pipes and to reduce

any effects on the membrane filters.

7. Irish Water should ensure that;

a. All staff receive the FETAC plant operators course training, as a minimum.

b. A review is undertaken of the cause of the elevated turbidity readings while the

treated water sample is being taken.

c. The DAF plant and the flocculation tanks are kept free of algal growth.

d. All unused chemicals, and the empty containers are removed from site, especially

those located at the source pump house, especially the expired potassium

permanganate and sodium hydroxide bulk tank.

e. All bulk storage tank fill points are located within bunds and that fill points are

locked.

f. All reservoirs are regularly inspected internally and cleaned out as appropriate.

g. All covers and vents are of the appropriate type to prevent surface water and vermin

ingress.

h. The use of chemical bait boxes is discontinued.

i. The area around the source is cleaned up and any unused/discarded material is

removed from the site to an appropriately authorised site.

FOLLOW-UP ACTIONS REQUIRED BY IRISH WATER

During the audit Irish Water representatives were advised of the audit findings and that action must be

taken as a priority by Irish Water to address the issues raised. This report has been reviewed and

approved by Ms Yvonne Doris, Drinking Water Team Leader.

Irish Water should submit a report to the Agency within one month of the date of this audit report

detailing how it has dealt with the issues of concern identified during this audit. The report should

include details on the action taken and planned to address the various recommendations, including

timeframe for commencement and completion of any planned work.

The EPA also advises that the findings and recommendations from this audit report should, where

relevant, be addressed at all other treatment plants operated and managed by Irish Water.

Please quote the File Reference Number DW2014/231 in any future correspondence in relation to this

Report.

Report prepared by:

Date: 15/07/2015

Niall Dunne

Inspector

8

Photograph 1: Cover at source inadequate to prevent vermin access.

Photograph 2: Algal growth in Flocculation tank.

9

Photograph 3: The fill points for the bulk storage tank were observed to be out the bunds.

Photograph 4: Unused bulk Sodium Hydroxide tank containing expired chemicals.

10

Photograph 5: Potassium Permanganate preparation tank area containing chemicals.

Photograph 6: Discarded materials at the source.

.