intensification and wetlands (aeration)...3baa, heathrow airport ltd, hounslow, middlesex, uk...

ABSTRACTS - WETPOL 2013 - October 13-17, 2013 - Nantes - FRANCE

180

Intensification and wetlands

(aeration)


181

Treatment of fish farm sludge supernatant with aerated filter

beds and steel slag filters —

Effect of organic matter and nutrient loading rate (O.35)

Margit Kõiva,b

, Kunaal Mahadeoa, Yves Comeau

a

aDepartment of Civil, Geological and Mining Engineering, Polytechnique Montreal, 2500

chemin de Polytechnique, Montreal (QC), H3T 1J4, CANADA ([email protected],

[email protected], [email protected])

bDepartment of Geography, Institute of Ecology and Earth Sciences, University of Tartu, 46

Vanemuise St., Tartu, 51014, ESTONIA

INTRODUCTION

Fish farms in Quebec, Canada, have to limit their phosphorus (P) discharge to the

environment to 4.2 kg P per ton of fish produced, according to the sustainable development

strategy for freshwater aquaculture of Quebec. For this purpose, fish food formulation and

fish rearing strategies have been improved, but rapid solids capture is required to prevent P

from being released to the supernatant and being discharged from the fish farms. Therefore,

settleable solids are removed by micro-screening and settling, and the sludge is stored in silos

and thickened. The silo supernatant, however, contains high concentrations of organic matter

and nutrients and it needs to be further treated before discharge.

The goal of our study was to develop an on-site method for the treatment of the

supernatant of the sludge silo of a trout farm that is cost-effective and environmentally

friendly. The main objectives of our experiment were to determine: 1) the effect of aerobic

treatment on organic matter, suspended solids and nitrogen removal; 2) the effect of different

void hydraulic retention times (HRTV) on P removal in slag columns; and 3) the treatment

efficiency of the hybrid system with different organic matter and nutrients loadings. On that

basis, design criteria should be proposed for a hybrid system consisting of aerated filter beds

for organic matter removal and steel slag filters for phosphorus retention.

MATERIALS AND METHODS

A pilot-scale system was set up at the “Les Bobines” fish farm in Quebec, with a treatment

sequence consisting of: two parallel up-flow aerated filter beds (AFBs; granite gravel 10-15

mm, volume 1.0 m3), followed by an up-flow sacrificial steel slag filter (SSF; volume 129 L),

and subsequent three parallel working two-stage up-flow steel slag columns (SCs; 5-10 mm;

volume of each column 95 L). The functions of the unit processes were: for AFBs to oxidize

organic matter and ammonia, for SSF to precipitate inorganic carbon and o-PO4, and for SCs

to precipitate o-PO4. During Phase 1 the steel slag (grain size 20-40 mm) in SSF was changed

after 184 days of utilization. The treatment efficiency of the sacrificial slag filter in Phase 1 is

presented according to the two periods as SSF1 (total 184 days) and SSF2 (total 77 days).

Furthermore, for Phase 2 the sacrificial slag filter was filled with finer steel slag (grain size

10-30 mm) and the effluent of this period is presented as SSF3.

The differences between the two experimental phases are presented in Table 1.

RESULTS

The results of Phase 1 demonstrated that the AFBs removed 95% of COD, 90% of TKN,

32% of TP but resulted in a 10% increase of o-PO4 in the supernatant (Table 1). The SSF1

and SSF2 removed an extra 20% TP and 30% o-PO4. The SCs showed high P removal


182

efficiency (95% TP and 98% o-PO4) and during Phase 1, with the low organic and nutrients

loading rates, there were no significant differences in the removal of P with different HRTV.

The results of Phase 2 with much more concentrated supernatant (Table 1) showed that in

the AFBs, 66% of COD, 38% of TKN, 81% of TP and 88% of o-PO4 was removed. The

average reduction of TP in SSF3 was 35% and in SCs 70%. However, the o-PO4 removal in

the SCs remained above 92%. During Phase 2, with a much higher P loading, the effect of

different HRTV in SCs became apparent and showed a rapid saturation of SC3A at the end of

Phase 2 (effluent o-PO4 1.9 mg P/L). Table 1. Characteristics and composition of supernatant during the two experimental phases.

Abbreviations: OLR - organic loading rate; HRTV – void hydraulic retention time; AFBs – aerated filter

beds, SSFs – sacrificial slag filters; SCs – slag columns.

Processes Parameters Units Phase 1 Phase 2

Experiment Duration months 8.5 3.0

COD Influent mg/L 364 5400

Removal % 98.1 67.2

TKN Influent mg/L 15.8 420

Removal % 97.5 42.9

TP Influent mg/L 5.3 160

Removal % 97.5 96.3

o-PO4 Influent mg/L 2.1 118

Removal % 99.8 99.5

pH Effluent 11.4 10.1

AFBs OLR kg BOD5/ m

3/d 0.015 0.52

HRTV d 2.0 2.7

SSF HRTV h 3.5 4.8

SC1A+SC1B

HRTV h

20+20 30+30

SC2A+SC2B 12+12 15+15

SC3A+SC3B 4.5+4.5 6+6

CONCLUSIONS

Aerated filter beds gave a high efficiency in organic matter mineralization and nitrification

with low organic loading rate during Phase 1. During Phase 2, however, nitrification was

almost non-existent, due to the high organic loading. Steel slag was very efficient for reactive

P removal through precipitation with calcium. Two-stage SCs showed a high efficiency in

removing TP and even more in o-PO4 removal during both Phases.

Estimated lifetime of SCs mostly depends on the effluent pH from the slag filters, a high P

removal efficiency being obtained as long as the pH remains above 9.

The choice of such a treatment system at full scale would depend on the concentration and

loading from the fish farm effluents and available space. These constraints would dictate the

nature of the system, and whether the treatment could be more extensive or should be more

intensive.

ACKNOWLEDGEMENTS

We thank the Natural Sciences and Engineering Research Council of Canada, the Société

de Recherche et Développement en Aquaculture Continentale, the Réseau Aquaculture

Québec, Matériaux Harsco and Arcelor Mittal for their financial support; and Les Bobines

fish farm, students and staff of Polytechnique Montréal and technicians Denis Bouchard and

Marie Ferland for their technical assistance.


183

Nutrient uptake in an aerated constructed wetland treating glycol

from de-icing operations at Heathrow Airport. (O.52) S. Wallace

1, C. Murphy

2, R. Knight

3, D. Cooper

2,

1Naturally Wallace Consulting LLC, Stillwater, Minnesota, USA

2ARM Ltd, Rugeley, Staffordshire, UK

3BAA, Heathrow Airport Ltd, Hounslow, Middlesex, UK

INTRODUCTION

The Mayfield Farm treatment system receives effluent collected from the Southern

Catchment of Heathrow Airport, a total of 290 hectares. During winter operations, weather-

related de-icing activity results in large shifts in the flow and concentrations in airport runoff.

The biological treatment of spent de-icing fluids is challenging because it involves the

treatment of a cold and nutrient-deficient wastewater with variable flows and concentrations.

Because the chemicals used for deicing (principally propylene glycol and ethylene glycol)

do not contain nitrogen or phosphorus, deicing runoff is typically nutrient-limited. Effective

treatment of deicing runoff requires adequate oxygen transfer in addition to providing

nutrients so that treatment bacteria can be sustained in the wetland system.

For waste streams that are lacking in nutrients such as nitrogen, phosphorus and

potassium, nutrients required for microbial treatment can be supplied through internal

biogeochemical cycles, or must be provided as a supplemental feed to the influent

wastewater.

DISCUSSION

One major unknown factor is the microbial yield of wetland treatment systems, especially

when subjected to peak loadings. The microbial yield can be defined as the ratio of microbial

biomass produced per kg of biochemical oxygen demand (BOD) removed. In mature wetland

systems, this yield ratio is believed to be quite low, on the order of 0.05, (Austin et. al., 2006)

since biofilms are mature and internal nutrient storages can be large relative to nutrient

demands. However, for systems relying on relatively immature microbial communities, such

as activated sludge systems, the yield ratio can be quite high, and approach 1.0 (Metcalf and

Eddy, 1998). In a recent study at the Buffalo Niagara International Airport, nutrient uptake in

a deicing treatment wetland was studied by Wallace and Liner (2010), who concluded that

the microbial yield could not have been less than 0.3.

During the 2012/2013 deicing season, the Mayfield Farm treatment wetland received large

mass loads of deicing runoff. The upgraded Mayfield Farm works also has on-line nutrient

dosing such that nitrogen and phosphorus were not limiting factors in the overall treatment

process. Based on the uptake of phosphorus relative to BOD removal, the aerated horizontal

subsurface flow wetland beds operated at a microbial yield ratio of 0.7, which is considerably

higher than previously reported in the literature for wetland treatment systems.

REFERENCES Austin, D., Maciolek, D., Davis, B., Wallace, S. (2006). Dämkohler number design method to avoid plugging

of tidal flow constructed wetlands by heterotrophic nitrification. Dias, V., Vymazal J. (eds.) Proceeding of the

10th International Conference on Wetland Systems for Water Pollution Control, 23-29 September 2006;

MAOTDR and IWA: Lisbon Portugal, pp. 1147-56.

Metcalf and Eddy Inc.. (1998). Wastewater Engneering, Treatment Disposal and Reuse. Tchobanoglous G.,

Burton F., Stensel H. (eds.) Fourth Edition, McGraw-Hill New York.

Wallace, S., Liner M. (2010). Nutrient limitations in industrial treatment wetlands. 2th International

Converence on Wetland Systems for Water Pollution Control, International Water Association, Venice Italy, pp.

1071-74


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Treatment performance of an aerated constructed wetland

treating glycol from de-icing operations at a UK airport. (O.59)

C. Murphy1, S. Wallace

2,

R. Knight

3, D. Cooper

1,

1ARM Ltd, Rugeley, Staffordshire, UK

2Naturally Wallace Consulting LLC, Stillwater, Minnesota, USA

3BAA, Heathrow Airport Ltd, Hounslow, Middlesex, UK

INTRODUCTION

Mayfield Farm Treatment System receives effluent collected from the Southern

Catchment of Heathrow airport, a total of 290ha. During winter operations, weather-related

de-icing activity results in large shifts in the flow and concentrations of airport runoff. The

biological treatment of spent de-icing fluids is challenging because it involves the treatment

of a cold and nutrient-deficient wastewater of variable flow and strength. After a successful

full scale trial to determine the efficacy of aerated wetlands, an entire treatment system was

optimised in 2011, consisting of a primary reservoir, partial and complete mix zones, a

balancing lagoon, and 12 aerated horizontal subsurface flow reed beds operating in parallel,

with a total area of 2.1 ha with a design loading rate of 1900 Kg BOD d-1

to the wetlands. The

original wetland system, commissioned in 2003 had a design loading rate of 590 kg BOD d-1

(Richter et al, 2003) at a flow rate of 40 L/s.

The whole system was designed to remove 3500 kg BOD d-1

at a design flow of 40 L/s.

The system has a combined capacity of >44,000m3 of wastewater with a retention time of

approximately 21 days, depending on the pump flow rate which varies between 40 and 80

L/s. Nutrient dosing points are located throughout the system to prevent nutrient deficiency

becoming a limiting factor in the development of a stable and viable mass of bacteria

necessary to achieve the required performance.

RESULTS

The system began operating in winter mode in October and has since been monitored

continually using a control system and lab analysis on effluent sampled 3 times per week

from 7 points throughout the system until April. Winter weather in the UK is unpredictable,

with fluctuating temperatures and rainfall. This results in periods of low loading, to highly

concentrated shock loads to the treatment works. The data from peak loading events for the

first year (2011/2012) and the second year (2012/2013) have been analysed for this paper.

The cumulative load for the first and second years was 23,875 Kg BOD and 48,013 Kg

BOD respectively (Figure 1.) which is due in part to increased use of glycol at the airport in

the second year due during prolonged periods of cold weather, and also effluent being

pumped through the system during the second year twice as fast as during the previous year

because of increased rainfall (Table 1.) The removal efficiency for BOD was 64% in the first

year and 85% in the second year. Areal loading and removal rates for the first year were 68

and 37 g/m2 d

-1 respectively compared with 155 and 87 g/m

2 d

-1 in the second year.

A P-k-C* data fitting model (Kadlec and Wallace, 2009) was completed using

performance and operational data for both years to produce first-order areal (KA20) and

volumetric (KV20) removal rate coefficients (k-rate). In the first year, the Kv was 0.03 d-1

at

an average temperature of 7.4 ˚C which equated to a KV20 of 0.585 d-1

and KA20 94 m/yr. In

the second year, the KV was 1.3 d-1

at an average temperature of 4 ˚C which equated to a KV20

of 1.417 d-1

and KA20 of 227.6 m/yr.


185

Figure 1. Cumulative loadings rates for the first and second year of operation compared to the design

load.

Table 1. Performance data for the wetlands.

DISCUSSION AND CONCLUSIONS

This system operated successfully, meeting the treatment requirements. K rates observed

in Table 1 are consistent with intensified wetlands, but probably could not have been

supported without mechanical aeration of the reed beds. The loading rates were considerably

higher than the design basis, as illustrated in Figure 1, and arrived at the system in a shock

loads rather than at a consistent loading rate.

REFERENCES Richter, K.M, Margetts, J.R., Saul, A.J., Guymer, I., Worrall, P. (2003). Baseline hydraulic performance of the

Heathrow constructed wetlands subsurface flow system. Water Science & Technology, Vol 47, No. 7-8, pp.

177-181

Kadlec, R., Wallace S. (2009) Treatment Wetlands, Second Edition. CRC Press, Boca Raton, Florida USA

units 2011/2012 2012/2013

Average Flow m3/d 3,140 6,052

Average Loading Kg/d 1445 3282

Average Removal Kg/d 790 1864

Average Loading g/m2.d 68.3 155

Average Removal g/m2.d 37 88

Average % removal % 63.6 85

Average HRT d 11 5

Average water temp ˚C 7.4 4

θ 0.65 0.99

KV20 m/d 0.585 1.417

KA20 m/yr 93.95 227.6


186

Hydraulic characterization and optimization of total nitrogen

removal in an aerated vertical subsurface-flow wetland (O.89)

J. Booga, J. Nivala

b, C. Sullivan

b, T. Aubron

b, K. Bernhard

b, S. Wallace

c, M.

van Afferdenb, R. Müller

b

a Helmholtz Center for Environmental Research-UFZ, Permoser Str. 15, Leipzig, 04318,

GERMANY ([email protected])

b Helmholtz Center for Environmental Research-UFZ, Permoser Str. 15, Leipzig, 04318,

GERMANY

cNaturally Wallace Consulting, 109 E. Myrtle Street, Stillwater, Minnesota 55082 USA

INTRODUCTION

Aerated treatment wetlands have been proven to offer higher treatment performance than

conventional systems for the removal of key pollutants such as organic carbon, total nitrogen,

ammonia nitrogen and pathogens. Thus high nitrate effluent concentrations caused by

continuous aeration may be a limitation to the trend moving towards more and more strict

getting discharge standards for small and decentralized wastewater treatment systems. This

study presents an optimization of nitrogen removal in a pilot-scale aerated vertical

subsurface-flow treatment wetland by intermittent aeration.

METHODS

Systems

Two pilot scale VSSF systems (6.2m² x 0.85m, qi=95 L/m²*d, tv=3.5d ) handling primary

treated domestic sewage. One system was planted with P.australis, and the other system was

unplanted. Treatment performance from the first 18 months of operation indicated similar

total nitrogen removal in the two systems (Nivala et al., 2013). Aeration was provided by

ForcedBedAeration™ using a 35W diaphragm pump. Air flow was measured with a Prandl

sensor to be 2200 L/h. The systems have internal sampling points at three different depths

(0.14m, 0.43m, 0.7m).

Experiments

In August 2012 the unplanted system (VF-i) was set from continuously to intermittent

aeration while the other remained with continuous aeration (VF-c). Intermitted aeration was

provided to VF-i in an 8 hours on / 4 hours off pattern. Systems have been sampled nearly

weekly (In-, Outlets) and monthly (internal) from August to mid November 2012 (Period of

Record, POR) for CBOD5, TOC, TN, NH4-N, NO3-N, NO2-N, DO and ORP. A tracer test

using Fluorescein (255mg per system) was also conducted in October 2012.

Data analyses

Median areal pollutant removal rates of the two systems during the POR, as well as before

the change in aeration were compared statistically (Kruskal-Wallace & Wilcoxen-Rank-Sum

Tests). Tracer data was analysed using a best fit tanks-in-series model with a Gamma

distribution (Kadlec and Wallace, 2009).

RESULTS AND DISCUSSION

Treatment performance

Mean removal rates of CBOD5, TOC, TN and NH4-N for VF-c were 32.1, 17.6, 6.3, 8.2

g/m²·d and for VF-i 32.1, 18.2, 7.8, 7.8 g/m²·d. Statistical analysis showed significant


187

differences for TN (p<0.001) and NO3-N (p<0.001) removal during the POR as well as one

for NO3-N during August 2011 - August 2012 (p=0.033). These results demonstrate

significantly enhanced TN removal with intermittent aeration. Improved nitrate removal is

argued but could not be proven as statistically significant. Additional treatment performance,

including internal concentration profiles, will be given in the presentation.

Hydraulics

Fluorescein tracer experiments resulted in NTIS of 1.1 (VF-c) and 1.2 (VF-i) indicating

hydraulics similar to that of a continuously-stirred tank reactor (CSTR) as shown in (Figure

1) The tracer testing confirms that the water in the system is extremely well-mixed, which

can be attributed to the opposing movement of the wastewater (downwards) and air

(upwards). Mass recovery rates were 52% (VF-c) and 66% (VF-i).

Fig. 1. Dimensionless retention time distribution (RTD) from the Fluorescein tracer experiment in an

intermittently aerated VSSF wetland.

CONCLUSIONS

An aerated VSSF wetland could be optimized by changing the aeration pattern from

continuous to intermittent. TN removal rates under intermittent aeration increased about 20%

compared to a continuously aerated VSSF while saving 33% of energy for electrical pumps.

Intermittent aeration had no significant effect on carbon removal or wetland hydraulics.

ACKNOWLEDGEMENTS

The authors acknowledges G. Weichert and K. Bernhard for their support in experimental

and laboratory work.

REFERENCES Kadlec, R.H. and Wallace, S.D. (2009) Treatment Wetlands 2

nd ed., CRC Press Boca Raton, Florida.

Nivala, J., Wallace, S., Headley, T., Kassa, K., Brix, H., van Afferden, M., Müller, R. (2013, in press).

Ecological Engineering. http://dx.dio.org/10.1016/j.ecoleng.2012.08.028

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188

Wastewater treatment in a compact intensified wetland system at

the Badboot; a floating swimming pool in Belgium (O.103)

D. Van Oirschot1, S. Wallace

2, R. Van Deun

3,

1

Rietland bvba, 2322 Minderhout, Belgium 2

Naturally Wallace Consulting LLC, Stillwater, Minnesota, USA 3

Department Agro- and Biotechnology, Thomas Moore Kempen, Geel, Belgium

INTRODUCTION

The Badboot is a floating swimming pool located in the city of Antwerp in Belgium.

A major design goal of the project was to make the ship as self-sufficient as possible,

including onsite treatment of wastewater. A treatment wetland system was constructed

onboard to treat wastewater from visitor locker rooms, showers, two bars, and a restaurant.

Due to the limited space onboard the ship, only 190 m2 could be allocated to a

wetland treatment system. As a result, part of the design included intensification of the

wetland treatment process through the use of Forced Bed AerationTM (FBA), which has been

implemented in a variety of wetland projects in the United Kingdom and North America

where intensification of wetland systems has been warranted.

FBA systems rely on the injection of small quantities of air at low pressure very

uniformly in saturated subsurface flow wetland systems to increase oxygen transfer. In terms

of the Badboot, the wetland treatment system was divided into a septic tank, a saturated

vertical down-flow subsurface wetland bed, followed by a horizontal flow subsurface wetland

bed. Both the vertical flow and horizontal flow beds occupied half of the wetland area, and

airflow was divided equally within the two beds.

The system has been monitored approximately every two weeks between September

2012 and March 2013 for flow, pH, chemical oxygen demand (COD), total nitrogen,

ammonia nitrogen, nitrate, total phosphorus, conductivity, and sulphate.

RESULTS

Analytical data from the first 6 months of operation are summarized in Table 1:

Table 1 - Badboot Wetland Average Monitoring Results

Parameter, mg/L Influent After VF After HF Overall

Removal Flow, m3/d 8.2 8.2 8.2 NA

pH 5.8 6.2 6.7 NA

COD 1848 34 9 99.5%

Total N 116 23 13 88.6%

Ammonia N 63 3 2 97.2%

Nitrate N 10 20 8 20%

Conductivity, µS/cm 1327 887 630 53%

Sulfate 11 56 37 Net increase


189

DISCUSSION

The intensified wetland at the Badboot showed excellent treatment performance over

the first six months of operation, especially for COD, ammonia, organic nitrogen and for total

phosphorus. Almost all of the removal occurred in the first stage of the wetland, which was a

saturated vertical down-flow process.

Removal of COD and non-oxidized forms of nitrogen can largely be attributed to

wetland aeration. If all COD was removed aerobically, plus the oxidation of ammonia and

organic nitrogen, then the first vertical flow wetland stage could have supported a maximum

oxygen consumption rate of approximately 200 g/m2-

d. This is considerably higher than the

aeration design, which was dimensioned around 70 g/m2-

d of oxygen transfer.

These rates of oxygen transfer are generally held to be beyond the range of passive

wetland systems (Kadlec and Wallace, 2009), but seem to be well within the range reported

for intensified wetlands with mechanical aeration systems (Wallace and Liner, 2010; Murphy

et. al., 2012; Nivala et. al., 2012).

Next to the excellent nitrification, also the total-N removal rate deserves attention.

Where passive VF wetlands often exhibit excellent nitrification but nitrate levels at the outlet

still tend to be high, such is not the case in this wetland. This seems to suggest that in aerated

wetlands next to aerobic zones, there are also sufficient anaerobic zones where denitrification

takes place. On average per m² 1,700 grams of total-N is removed per year in the Badboot

wetland. If some organic carbon (as represented by COD) was carried over from aerated to

anaerobic zones, this would partially explain the high rate of nitrogen removal observed in

the VF wetland cell. In any event, on a stoichiometric basis, this high rate of nitrogen

removal can only be explained by simultaneous nitrification and denitrification, or by

alternative nitrogen processes such as anammox (Tanner and Kadlec, 2002; Sun and Austin,

2006).

The daily COD-load to the total wetland is 11.3 kg. The VF cell is loaded with 118 g

COD/m²-day which is about 3 times higher than the organic load on passive VF wetlands

common in Belgium, which confirms the choice of an intensified wetland in this project.

The high rate of phosphorus removal can likely be attributed to the use of iron filings

as a reactive media within the wetland bed, which is another form of wetland intensification.

REFERENCES

Kadlec, R., Wallace S. (2009). Treatment Wetlands, Second Edition. CRC Press, Boca

Raton Florida.

Murphy, C., Wallace S., Cooper D. (2012) Treatment performance of two aerated

saturated vertical flow constructed wetlands treating settled sewage. Proceeding of the 13th

International Conference of Wetland Systems for Water Pollution Control, Perth Australia,

pp. 154-158.

Nivala, J., Wallace S., Brix, H., Headley, T., Kassa, K., van Afferden, M., Muller, R.

(2012). Conventional and intensified subsurface flow treatment wetlands: Performance-

based analysis using the P-k-C* model. Ph.D. Dissertation, Department of Bioscience,

Aarhus University, Denmark.

Sun., G., Austin, D. (2006). A mass balance study on nitrification and deammonification

in vertical flow wetlands treating landfill leachate. Proceedings of the 10th International

Conference on Wetland Systems for Water Pollution Control. Lisbon, Portugal, pp. 187-196.

Tanner, C., Kadlec, R. (2002). Oxygen flux implications of observed nitrogen removal

rates in subsurface flow treatment wetlands. Proceedings of the 8th International Conference

on Wetland Systems for Water Pollution Control. Dar Es Salaam, Tanzania, pp. 972-981.

Wallace, S., Liner M. (2011). Design and performance of the wetland treatment system at

Buffalo Niagara International Airport. IWA Specialist Group on the Use of Macrophytes for

Water Pollution Control; Newsletter No. 38.


190

What is the potential of windmill driven aerated wetland systems? (O.113)

C. Sullivana, J. Nivala

a, J. Boog

a, T. Aubron

a, S. Wallace

b,

M. van Afferdena, R. Müller

a

a Helmholtz Center for Environmental Research-UFZ, Permoser Str. 15, 04318 Leipzig

GERMANY ([email protected]) bNaturally Wallace Consulting LLC, P.O. Box 2236, 109 E. Myrtle Street, Stillwater

Minnesota 55082, USA

INTRODUCTION

Aerated treatment wetlands are gaining increased attention due to their ability to provide

higher levels of treatment compared to other treatment wetland technologies, specifically in

regards to removal of key pollutants such as organic carbon, ammonium nitrogen and

indicator organisms such as E. Coli (Wallace, 2001; Nivala 2012). Despite significant

advantages including relatively low energy demands compared to other wastewater treatment

technologies, aerated wetland systems have the disadvantage of requiring external energy

inputs. In order to retain the benefits of aerated treatment wetlands and yet reduce the

ongoing costs and requirement for electricity, the UFZ has undertaken an investigation into

the potential of a windmill driven air pump for providing aeration to a treatment wetland

system.

METHODS

A trial was established in 2012 at the Langenriechenbach ecotechnology research centre

approximately 50 km from Leipzig in Eastern Germany. The three systems included in this

study are described in Table 1. The H50p system is not connected to an aeration supply and

therefore remains as a standard horizontal subsurface flow constructed wetland. The HAc

system is joined to two electrically driven pumps which provide continuous aeration. The

windmill aeration for the HAw system is provided by a windmill unit positioned on a 3 m

tower with a 6-blade rotor which powers twin piston air pumps. For the purpose of this

study, both aerated systems were run at design flow rate for the continuously aerated wetland.

Table 1. Summary of the treatment systems in this study. System

Abbreviation

Aeration Type Main Media Vegetation Design

Flow

(L/d)

Effective

Depth

(m)

Area

(m2)

HRT

(d)

H50p None 8 – 16 mm gravel P. australis 200 0.5 5.6 5.5

HAc Continuous electric aeration 8 – 16 mm gravel none 725 1.0 5.6 3.5

HAw Windmill aeration 8 – 16 mm gravel P. australis 725 1.0 5.6 3.5

Inlet and outlet water quality data have been collected weekly from August 2012 – March

2013 for the following parameters: 5-day carbonaceous biochemical demand, total suspended

solids, total organic carbon, total nitrogen, ammonium, nitrate, nitrite as well as E. coli.


Preliminary results indicate a significant variation in water quality characteristics based on

treatment approach. The HAc system provides excellent CBOD5, total nitrogen removal and

E. Coli removal in comparison to the other systems. This can be attributed to the continuous

oxygen supply which is assumed to be a limiting factor in both the windmill driven and

normal subsurface flow systems. A brief summary of water quality results are presented in

Table 2.


191

Table 2. Mean water quality results Parameter Influent Effluent HAw Effluent HAc Effluent H50p

CBOD5 (mg/L) 257.0 36.0 1.8 61.5

TOC (mg/L) 152 40.2 20.5 37.1

TN (mg/L) 76.9 66.9 50.4 63

NH4-N (mg/L) 60.9 46.5 1.6 62.3

NO3-N (mg/L) 0.3 11.2 27.6 0.19

NO2-N (mg/L) 0.1 0.37 Below detection 0.03

TSS (mg/L) 145.5 8.0 34.6 5.73

E.coli (MPN/100 mL) 6.28E+06 6.E+04 7.E+02 3.E+05

The water quality results were used to establish mass removal rates for the HAw system. This

information was then compared to local wind speed data (Figure 1).

Figure 1. Mass removal rates versus wind speed

The results show that the windmill driven system can provide a TN removal of 0 to 5 g/m2

per day, while it can achieve a removal of TOC of between 15 to 25 g/m2 per day. When this

data is correlated with wind speed it suggests that there is a weak yet positive relationship for

both TN removal and wind speed (R2 = 0.41) and TOC removal and wind speed (R

2 = 0.27).

CONCLUSIONS

While demonstrating that the provision of windmill driven aeration can contribute to greater

mass removal during periods of high wind speed, this initial comparison shows that the

windmill powered system generally performed better than the standard subsurface horizontal

flow system but not as good as the continuously aerated wetland system. These results

indicate that the air flow from the windmill pump varies but that even in windy conditions,

the windmill-driven air pump may provide less oxygen to the subsurface than calculated

based on the manufacturer’s specifications. While providing positive initial findings it is

suggested that further investigation in a variety of environmental contexts is required to

establish the true potential of windmill driven aerated wetland systems.

REFERENCES Nivala, J (2012) Effect of design on treatment performance, plant nutrition and clogging in subsurface flow

treatment wetlands. PhD Dissertation, Department of Bioscience, Aarhus University, Denmark.

Wallace, S.D., 2001. Patent: System for removing pollutants from water. United States: US 6,200,469,B1.

y = 3.3147x + 14.073

R2 = 0.2717

y = 1.1262x + 0.9561

R2 = 0.41330

5

10

15

20

25

30

0.00 1.00 2.00 3.00 4.00

WIND SPEED [m/s]

AR

EAL

MA

SS R

EMO

VA

L R

ATE

[g/

m²*

d]

TOC

TN

Linear (TOC)

Linear (TN)


192

Comparison of the nitrification potential of passive and aerated

horizontal subsurface flow constructed wetlands (O.119)

Kinfe Kassaab, Tom Headley

a, Jaime Nivala

a, Katy Bernhard

a Manfred van

Afferdena, Matthias Barjenbruch

b, Roland Müller

a

aEnvironmental and Biotechnology Centre, Helmholtz Centre for Environmental Research

(UFZ), Permoserstrasse 15, Leipzig 04318, Germany.

bTU Berlin, FG Siedlungswasserwirtschaft, Sekr. TIB 1B 16, Gustav-Meyer-Allee 25, D -

13355 Berlin

Abstract

To study the effect of depth and role of plants and aeration on the treatment performance of

HSSFCWs, 6 pilot scale beds (1.2m wide x 4.7m long) with a water depth of 0.25m

(H25,H25p) (passive) and 0.5m (H50, H50p) (passive), 1 m (HA, Hap) (aerated) 2 beds

(planted and unplanted) of each were constructed in Langenreichenbach, Germany. The beds

were commissioned in June 2010 and were loaded with primary treated municipal sewage.

In order to quantify the distribution of nitrifying bacteria and oxygen, potential nitrification

activity of microbial biomass was carried out on the wetlands gravel and root samples over a

period of 24 hours. Samples were taken in May 2011 and February 2011 and the average

values in each month used to determine the nitrification potential of the wetlands. The test

media used for incubation were a buffer with excess ammonium at 200c in bottles by shaking.

Nitrate and nitrite production and ammonium removal were measured every 4 hours to

calculate the nitrification potential.

sampling points

H25

p-in

H25

p-ou

t

H25

-in

H25

-out

H50

p-in

H50

p-ou

t

H50

-in

H50

-out

nit

rifi

cati

on

po

t.(n

g N

O3- -N

/(g

.DW

gra

vel.h

r))

-2

0

2

4

6

8

10

12

sampling points

HAp-

in

HAp-

out

HA-in

HA-o

ut

nitrifica

tio

n p

ot. (

ng N

O3- -N

/(g

.DW

gra

ve

l.h

r))

0

20

40

60

80

100

120

140

160

Figure: 1 Nitrification potential of gravel as ( ng NO3-N/ (g dry weight gravel hour)) against the

beds gravel sampled in May 2011. The left side sampled from the passive wetlands and the right

side from aerated wetlands


193

Figure 1 shows the nitrification potential of gravel collected from six wetlands. The

nitrification potential of the biofilm in the inlet of the aerated beds was higher than the outlet

of the aerated beds. On the contrary, the passive systems (25 cm and 50 cm effective depth)

showed higher biomass nitrification potential at the outlet than the inlet. This is because the

population of nitrifying bacteria is related to the availability of oxygen and ammonia in the

system (Bastviken and others 2003). Aerated systems had high air supply and continuous

supply of ammonia from the raw wastewater from inflow side and the passive beds had

dissolved oxygen relatively improved towards the outlet side and ammonia was available in

the whole bed although there was variation. Again the higher nitrification potential the root of

the aerated beds was shown in Figure 2. The nitrification potential of the root biofilm was

higher than the gravel biofilm and therefore the nitrification potential of the planted beds

were higher than the unplanted beds in the

aerated and passive systems. This might be

to the relative aerated condition of the

outlet for the 0.25m bed.

Figure: 2 Nitrification potential of root

samples collected in May 2011 from the inlet

and outlet side of 25 cm, 50 cm and 100 cm

deep wetlands.

Besides it was found that sample collected

in May 2011 sample had predominantly

higher nitrification potential than February

2011 gravel samples.

From our results it is concluded that,

nitrification potential experiment is an easy

experiment used to predict roughly the

nitrifying bacteria distribution in a wetland. A clearly visible high nitrification potential

difference was found between the aerated and the non-aerated beds. Planted aerated beds had

higher nitrification potential than unplanted aerated beds and both planted and unplanted

aerated systems had high nitrification potential at the inflow side than outflow side. When

passive H25p, H50p, H25 and H50 were compared, planted beds had higher nitrification

potential than the unplanted and therefore most nitrifying bacteria were found in the root

biofilm of the plants than gravel biofilm. When the H25p and H50P were compared, the

Nitrification potential of the outlet side of H25p bed was higher than the H50p bed and the

inlet side nitrification potential of the H50p bed was higher than H25p bed. In addition, the

nitrification experiment showed that seasonal variation affects the distribution of nitrifying

bacteria in the wetlands and therefore the May 2011 nitrification potential was higher than the

February 2011. This method is a simple tool to compare which wetland has nitrifying bacteria

distribution relative to the other wetland.

References:

Bastviken, S.K.; Eriksson, P.G.; Martins, I.; Neto, J.M.; Leonardson, L.; Tonderski, K. Potential Nitrification

and Denitrification on Different Surfaces in a Constructed Treatment Wetland J Environ Qual. 32:2414-2420;

2003

sampling points

25 cm

plant

ed in

25 cm

plant

ed o

ut

50 cm

plant

ed in

50 cm

plant

ed o

ut

aera

ted

plan

ted

in

aera

ted

plan

ted

out

nitrifica

tio

n p

ote

ntia

l (m

icro

g N

O3- -N

/(g

.DW

ro

ot.h

r))

0

10

20

30

40

50

60


194

Domestic wastewater and wetlands


195

Behaviour of a 2-stage vertical flow constructed wetland

under peak loads (O.32)

Alexander Pressl, Raimund Haberl, Guenter Langergraber

Institute for Sanitary Engineering and Water Pollution Control, University of Natural

Resources and Life Sciences, Vienna (BOKU), Muthgasse 18, A-1190 Vienna, AUSTRIA

([email protected])

INTRODUCTION

Using single-stage vertical flow (VF) constructed wetlands (CWs) that are designed

according to the Austrian design standards (ÖNORM B 2505, 2009) and that are operated

with an organic load of 20 g COD.m-2

.d-1

(i.e. 4 m² per person equivalent (PE)) the

requirements of the Austrian standards (1.AEVkA, 1996) regarding maximum effluent

concentrations can be met.

To increase nitrogen removal a two-stage VF system has been developed (Langergraber

et al., 2008, 2010, 2011). With the two-stage VF CW system, designed and operated with an

organic load of 40 g COD.m-2

.d-1

(i.e. 2 m² per PE), besides meeting the requirements of the

Austrian regulation regarding organic matter removal and nitrification, stable nitrogen

removal efficiencies can be achieved. A nitrogen elimination rate of 3.8 g N.m-2

.d-1

(or

1'380 g N.m-2

.yr-1

) and a nitrogen removal of 62 % was observed. Compared to nitrogen

removal rates of other CW systems treating municipal wastewater, a high nitrogen removal

rate can also be achieved under peak loads using this two-stage VF CW system. This paper

describes the results of the first full-scale implementation with real loading conditions.


The full-scale two-stage VF CW system was constructed for the Bärenkogelhaus which is

located on top of a mountain located in Styria (Austria) 1168 m above sea level. The

Bärenkogelhaus is a restaurant with 70 seats and 16 rooms for overnight guests and is a

popular site for day visits especially during weekends and public holidays. Based on this base

data, the system was designed for a hydraulic load of 2'500 L.d-1 with a specific surface area

requirement of 2.7 m² per PE). After a period of time with normal loading conditions, the

operation of the Bärenkogelhaus changed more and more to an event location. The first

events have been taken place in July 2011.

Both beds of the two-stage VF CW system have a surface area of 50 m² and are loaded

intermittently with mechanically pre-treated wastewater. A grease separator and modified

3-chamber-pit (also used for hydraulic buffering) is used for pre-treatment, and siphons are

used for the hydraulic loading. The 50 cm main layer of stage 1 consists of sand with a grain

size distribution of 2-4 mm, the 50 cm main layer of stage 2 of sand with a grain size

distribution of 0.06-4 mm. Both stages have a 10 cm top layer of gravel (4-8 mm) and are

planted with Phragmites australis.

On-line measurements (bed-soil and water temperature, loading amount) and periodic

standard grab sampling (every 2 weeks) were carried out as periodic monitoring-programme.

For the special investigations during the events the influent and the effluent of both beds were

supplied with automatic samplers (every 3 hours over a period of 6 days). Collected samples

have been analysed for TSS, BOD5, COD, NH4-N, NO2-N, NO3-N, and TN in the lab of the

Institute for Sanitary Engineering at BOKU University using standard methods.


196


The system built in fall 2009 and started operation in April 2010 when the restaurant was

opened. During the period July – December 2010 the hydraulic load of the system was

10.1 mm.d-1

and the organic load 10.3 g COD.m-2

.d-1

. In average the two-stage system

received in 32 % of its design load only. During the whole period the ammonia nitrogen

effluent concentration was below 1 mg/L even at effluent water temperatures below 3°C.

A special focus was drawn in the year 2012 of sampling campaigns for outstanding social

events (resulting in peak loads, as presented in the figure below) with a bigger amount of

guests at the Bärenkogelhaus. At this time the restaurant was open only at events like

weddings, music sessions, art exhibitions, etc. Therefore the calculated average daily

hydraulic load for the period July 2011 to September 2012 was only 15% of the designed

hydraulic load.

ACKNOWLEDGEMENTS

The experiments were carried out in the course of the research project ‘Begleitende

Untersuchungen zur praktischen Anwendung eines zwei-stufigen bepflanzten Bodenfilters

beim Gasthaus Bärenkogel (Investigations for practical application of a 2-stage CW system at

the Bärenkogelhaus)’ funded by the Austrian Ministry for Agriculture, Forestry, Environment

and Water Management and by the federal government of Styria (Amt der steiermärkischen

Landesregierung, Fachabteilung 19A, Wasserwirtschaftliche Planung und

Siedlungswasserwirtschaft). The authors are grateful for support and especially thank family

Hammer, the owners of the Bärenkogelhaus for their support on-site.

REFERENCES 1.AEVkA (1996): 1. Abwasseremissionsverordnung für kommunales Abwasser (Austrian regulation for

emissions from domestic wastewater). BGBl. 210/1996, Vienna, Austria [in German].

Langergraber, G., Leroch, K., Pressl, A., Rohrhofer, R., Haberl, R. (2008): A two-stage subsurface vertical flow

constructed wetland for high-rate nitrogen removal. Water Sci Technol 57(12), 1881-1887.

Langergraber, G., Pressl, A., Leroch, K., Rohrhofer, R., Haberl, R. (2010): Comparison of the behaviour of one-

and two-stage vertical flow constructed wetlands for different load scenarios. Water Sci Technol 61(5), 1341-

1348.

Langergraber, G., Pressl, A., Leroch, K., Rohrhofer, R., Haberl, R. (2011): Long-term behaviour of a two-stage

CW system regarding nitrogen removal. Water Sci Technol 64(5), 1137-1141.

ÖNORM B 2505 (2009): Bepflanzte Bodenfilter (Pflanzenkläranlagen) – Anwendung, Bemessung, Bau und

Betrieb (Subsurface-flow constructed wetlands – Application, dimensioning, installation and operation).

Österreichisches Normungsinstitut, Vienna, Austria [in German].


197

Experiences of the installation, operation and maintenance of

constructed wetlands in rural communities: case of study in

Pátzcuaro’s basin, México (O.76)

Juan Gabriel Garcia Maldonadoa, Indira Yarely López Cortes

b, Carlos Erasto

González Aguirrec

a Instituto Mexicano de Tecnología del Agua, Coordinación de Hidráulica, Subcoordinación

de Tecnología Apropiada e Industrial, Paseo Cuauhnáhuac 8532, Col. Progreso, C.P. 62550,

Jiutepec, Morelos, MÉXICO ([email protected])

bUniversidad de Guanajuato, División de Ingenierías. Av. Juárez 77, Col. Centro, C.P. 36000,

Guanajuato, Guanajuato, MÉXICO ([email protected])

cComisión Eztatal del Agua y Gestión de Cuencas del Estado de Michoacán, Santos

Degollado 723, Esq. Blvd. Arriaga Rivera, Col. Nueva Chapultepec Sur, C.P. 58290,

Morelia, Michoacán, MÉXICO ([email protected])

INTRODUCTION

Due to the low percentage of coverage of sewer and the lack of infrastructure for the

treatment of the waste water, the discharges generated by the populations who are located

around the lake of Pátzcuaro are spilt without treating or with a deficient treatment, situation

that has come spoiling the quality of the basin. With the purpose of helping to diminish the

impact generated by this problematic, the installation of collectors and systems of treatment

to drive and to treat the wastewater respectively it has been raised.

The offer arose as an initiative of the Mexican Institute of Water Technology (IMTA) and

the Gonzalo Río Arronte Foundation (FGRA), before the need of treat the discharges of

wastewater spilt on the lake of Pátzcuaro. The proposition took form in the frame of the

"Program of environmental recovery of the lake of Pátzcuaro" by means of an agreement

between both Institutions and the Municipalities that count with constructed wetlands.

METHODS

Up to 2009, four full-scale constructed wetlands have been installed around of the lake of

Pátzcuaro in rural communities (Cucuchucho, Santa Fe de la Laguna, Erongarícuaro y San

Jerónimo Purenchécuaro) and two more systems are in process of installation (one system in

San Jerónimo Purenchécuaro and one more in San Francisco Uricho). The constructed

wetlands studied receive wastewater flow ranging from 129.6 to 216 m3/day.

As part of the study, experts and operators of constructed wetlands were interviewed to

determine the factors of success and of failure (political, economic, social, technical, planning

and administrative) in the installation, operation and maintenance of the constructed

wetlands.


The meticulous review of these lists of the factors of success and of failure is important for

the one who plans constructed wetland installation, in order to foresee how they are going to

attend and to avoid the possible factors of failure, and how it is possible to foment the

practice of factors of success.


198

CONCLUSIONS

A review of practical projects of constructed wetlands implemented in rural communities

around of Pátzcuaro’s lake was conducted to highlight wetland performance in wastewater

treatment. Specific opportunities and limitations as well as problems and recommendations

were also discussed.

ACKNOWLEDGEMENTS

The authors wish to thank the Foundation Gonzalo Rio Arronte for their financial support.

REFERENCES Garcia, M. J.G. et al. (2012). Evaluación Integral (eficiencia, capacitación, seguimiento y apropiamiento) de

humedales. Informe final. Instituto Mexicano de Tecnología del Agua.

IMTA (2009). Memoria ilustrada del programa para la recuperación ambiental de la cuenca del lago de

Pátzcuaro. Avances 2003 - 2008. ISBN 978-968-5536-99-8. Jiutepec, Morelos. 152 pp.


199

Treatment of Domestic Wastewater in Full-Scale Hybrid

Constructed Wetlands Following Anaerobic Pretreatment: Two

Cases in a Drinking Water Catchment Area (O.95)

Selma Ç. Ayaz1, Özgür Aktaş

1,2*, Lütfi Akça

3,4, Nur Fındık

1

1TUBITAK Marmara Research Center, Environment and Clean Production Institute, 41470, Pbox:21, Gebze,

Kocaeli, Türkiye 2Istanbul Medeniyet University, Department of Bioengineering, Goztepe, Istanbul, Türkiye

3Istanbul Technical university, Environmental Engineering Dept., Maslak, Istanbul, Türkiye

4Ministry of Forestry and Hydraulic Works, Ankara, Türkiye

*Corresponding author (E-mail:[email protected])

EXTENDED ABSTRACT

The study involves treatment of domestic wastewater sequentially by anaerobic reactors

followed by horizontal (HFCW) and vertical (VFCW) sub-surface flow constructed wetlands.

Two full-scale systems constructed in Balçık and Oruçoğlu Villages, which are located in the

water catchment area of Omerli Dam Lake, the drinking water reservoir of Istanbul, and were

operated in order to treat the domestic wastewaters of about 2000 and 500 inhabitants,

respectively.

Anaerobic treatment of domestic wastewater served as a pretreatment step before the

constructed wetland systems. Anaerobic pretreatment was performed by an up-flow

anaerobic sludge bed reactor (UASB) in Balçık and an anaerobic baffled reactor (ABR) in

Oruçoğlu. The 297 m3

UASB reactor in Balçık Village treated domestic wastewater with a

hydraulic loading rate of 300 m3/day at ambient temperatures which was observed in the

range of 12 to 25C (psychrophilic and/or sub-mesophilic) depending on the seasonal

variations. The ABR reactor in Oruçoğlu had a volume of 44.4 m3

and was operated at

ambient temperatures in the range of 11 to 25C.

Anaerobically pretreated wastewater was first introduced into parallel HFCWs and then

parallel VFCWs before being discharged. In Balçık, anaerobically pretreated wastewater was

introduced into the hybrid two-stage serially operated sub-surface flow constructed wetland

system. The HFCW system was consisted of 4 parallel HFCWs (each 675 m2) whereas

VFCW system was consisted of 3 parallel VFCWs (each 750 m2). The performance of the

treatment system was monitored for about 10 months. In Oruçoğlu, anaerobically pretreated

wastewater was introduced into 3 parallel HFCWs and 2 parallel VFCWs operated in series.

Total area of the CW system is 750 m2, where HFCWs were located on 500 m

2 and VFCWs

on 250 m2. The performance of the treatment system was monitored for about 19 months.

The influent and effluent concentrations at each stage of the treatment systems and the

corresponding removal efficiencies are shown in Tables 1 and 2.

Table 1. Concentrations and removal efficiencies at each stage of the treatment system in Balçık Village

COD BOD5 TN TP TSS

Influent (mg/L) 333±222 124±80 44±25 4±4 157± 114

UASB Effluent (mg/L) 167±128 63±45 35+20 3.2±3.2 52±15

UASB Removal Efficiency (%) 52±17 54±14 32+16 - 62±21

HFCW Effluent (mg/L) 54±35 21±15 29±14 2.7±2.6 6±4

HFCW Removal Efficiency (%) 60±18 55±18 24±15 - 84±12

VFCW (Whole System) Effluent (mg/L) 29±21 12±8 21±12 1.8±1.7 5±1

VFCW Removal Efficiency (%) 50±20 48±22 30±20 - -

Whole System Efficiency (%) 88±5 89±6 57±26 - 94±5


200

Table 2. Concentrations and removal efficiencies of the treatment system in Oruçoğlu Village

COD BOD5 TN TP TSS

Influent (mg/L) 211±175 89±76 31±22 5.7±3.8 121±88

ABR Effluent (mg/L) 102±82 50±37 23±14 4.6±3.9 44±26

ABR Removal Efficiency (%) 45±21 42±20 27±20 26±15 51±26

CW System Effluent (mg/L) 31±24 12±9 17±10 2.6±1.6 10±9

Whole System Efficiency (%) 83±13 81±14 39±19 53±24 90±8

The two full-scale constructed wetland systems performed above 80 % COD, 40 % total

nitrogen (TN) and 90 % suspended solids removal on average. These efficiencies achieved

the project goals and were in accordance with the results in literature. The effluent from the

system met the Turkish discharge standards for treated domestic wastewaters with effluent

concentrations much lower than the limits for organic matter and suspended solids parameters

given as COD:120 mg/L, BOD5:50 mg/L and TSS:150 mg/L in Turkish Water Pollution

Control Regulation for the domestic wastewaters treated in constructed wetlands. There is no

limit for TN and TP in Turkish Water Pollution Control Regulation. On the other hand,

Urban Wastewater Treatment Directive necessitates effluent concentrations of COD:125

mg/L, BOD5:25 mg/L, TSS:60 mg/L, TN:15 mg/L and TP:2 mg/L for populations above

10000. These requirements were not always met for TN and TP, although effluent

concentrations were usually close to discharge limits. However, since the populations of

Balçık and Oruçoğlu Villages are 2000 and 500, respectively, the requirements of Urban

Wastewater Treatment Directive do not apply. Therefore, it may be proposed that these

hybrid CW systems are not suitable for populations above 10000 in Turkey because they may

not satisfy the requirements for nutrients.

The effluents of the plant also met the requirements for reuse as irrigation water with

effluent BOD<20 mg/L, TSS <30 mg/L and pH between 6-9 as declared by Turkish

regulations. However, the effluent should be disinfected to have fecal coliform less than 200

per 100 mL in order to be used for irrigation purposes. Agricultural irrigation is

recommended when the receiving media is particularly a lake, since it may prevent the

eutrophication risk caused by nitrogen and phosphorus. On the other hand, if the wastewater

should be discharged rather than being used for irrigation, it may be recommended to

increase removal of nitrogen and phosphorus particularly in the watersheds of drinking water

reservoirs.

As a conclusion, the results of the two full-scale cases showed that constructed wetlands

can be successfully used to solve wastewater problems of communities below 2000 in

Mediterranean countries such as Turkey, particularly in regions with moderate to high

temperatures.


201

Treatment Efficiency of Two Pilot-Scale Vertical Flow

Constructed Wetlands in Jordan (O.140)

Ghaida Abdallata, b

, Iyad Zreiqatc, Thomas Aubron

a, Jaime Nivala

a, Bassim

Abbassic, Marion Martienssen

b, Manfred van Afferden

a, Roland. A. Müller

a

a Environmental and Biotechnology Centre (UBZ), Helmholtz Centre for Environmental

Research (UFZ) Permoserstrasse 15, 04318 Leipzig, Germany. ([email protected])

b Department of Biotechnology, Brandenburg University of Technology, Siemens-Halske-

Ring 8, 03046 Cottbus, Germany. c Department of Water Resources and Environmental Management, Al-Balqa Applied

University, 19117 Al-Salt, Jordan.

INTRODUCTION

Efficient water management in arid and semi-arid regions is of paramount importance. In the

Middle East, Jordan is facing big challenges regarding its water resources. Population

growth, urbanization, and agricultural demands increase pressure on available fresh water

resources (MWI, 2001). Thus, the treatment and reuse of wastewater is considered a necessity

to satisfy the increasing demands for irrigation. Constructed wetlands are considered to be an

efficient technology for the treatment and reuse of wastewater.


Within the context of the SMART project (Sustainable Management of Available Water

Resources with innovative Technologies) a research and demonstration site for decentralized

wastewater treatment systems has been established in Fuhais, Jordan. The pilot facility has

access to raw municipal wastewater from the nearby treatment plant. Two pilot-scale vertical

flow constructed wetlands (VFCWs) were installed to evaluate the ability of different designs

to meet the Jordanian Standards (JS893/2006) presented in Table 1. The two VFCW systems

have been monitored for steady state performance, and operational changes which will take

place in late 2013 will aim to optimize the performance of these treatment systems especially

for total nitrogen (TN) and E.coli.

Table 1: Jordanian effluents standards for a reuse for reuse of treated wastewater (JS893/2006).

Parameter BOD

(mg/L)

COD

(mg/L)

TSS

(mg/L)

pH NO3- N

(mg/L)

TN

(mg/L)

E.coli

(MPN/100mL)

A: Cooked vegetables, and

sides of roads within city limits 30 100 50 6-9 30 45 100

B: Fruit trees, sides of roads

outside city limits 200 500 150 6-9 45 70 1000

Description of the VFCWs

The first system (ECO-1) is a recirculating unsaturated bed of fine gravel with a 3:1

recirculation ratio. The second system (ECO-2) is a multi-stage single pass filter consisting of

two unsaturated beds. Table 2 summarizes the design parameters of the two VFCWs. Each

system has a septic tank which provides primary treatment to the water before it is dosed to

the wetland system.

The systems were monitored over one year, on a weekly basis for the following parameters

CBOD5, COD, TSS, TN, NH4-N, NO2-N, NO3-N, TP, PO4-P, turbidity, E. coli, and the field

measurements (EC, pH, redox potential, dissolved oxygen, lab and field temperature).


202

Table 2: The main design characteristics of the ECO -1 and ECO-2 systems.


The results from ECO-1 show that the system removed respectively 94%, 97%, and 85% of

TSS, CBOD5 and COD. In addition, the TN concentration in this design was reduced around

50% as a result of the recirculation of the effluent and an improvement of the denitrification

process. The removal efficiency of ECO-2 was 95% - 98% for COD, TSS, and CBOD5

whereas, the TN removal was very low (21%), as a result of high effluent NO3-N

concentrations. The E. coli reduction was 3 log of ECO-1 and 5 log of ECO-2. Both designs

are capable to produce well-nitrified effluents, but the low reduction in TN was limited

because of limited denitrification and a concentration of approximately 10 -12 mg/L organic

nitrogen in the effluent.

Table 3. The chemical analysis (average values) for the Raw, influent, and effluents of VFCWs.

Parameter COD

(mg/L)

CBOD5

(mg/L)

TN

(mg /L)

NH4-N

(mg/L)

NO2-N

(mg/L)

NO3-N

(mg/L)

TSS

(mg/L)

PO4-P

(mg/L)

E. coli

Geometric

mean

(MPN/100mL)

Raw 970 338 114 58 0.1 0.4 355 6.2 6.6*107

Septic-1 590.8 163.5 99.7 68.6 0.034 0.38 205 13.5 3.6*106

ECO-1 46.3 11.1 51.3 3.6 0.6 41.1 7.5 6.5 9.5*104

Septic-2 501 157.7 98.2 70.6 0.03 0.4 114.7 8.5 3.9 *106

ECO-2 20.9 6.7 78.9 0.03 0.01 67.1 1.4 3.0 3.4 *102

FUTURE WORK

The removal efficiency of the VFCWs shows that the systems are close to meet the Jordanian

standards A and B for the reuse of treated wastewater. The modifications of these systems

aim to enhance TN (denitrification process) and E. coli removal. Preliminary post-

modification results will be presented at the conference.

ACKNOWLEDGEMENTS

This work was supported by funding from the German Ministry of Education and Research

(BMBF) within the context of the SMART project (Ref. 02WMI1080). Ghaida Abdallat

acknowledges the Helmholtz Interdisciplinary Graduate School for Environmental Research

(HIGRADE) and the Helmholtz Centre for Environmental Research (Helmholtz Zentrum für

Umweltforschung-UFZ) for additional funding and support.

REFERENCES

MWI/ARD,(2001) Plan for Managing Water Reuse in the Amman-Zarqa Basin and the

Jordan Valley, Water Reuse Component, Water Policy Support, Ministry of Water and

Irrigation, Amman, Jordan.

VFCWs

System

Saturation

status

Media

Hydraulic

loading rate

(L/m2.d)

Bed

Area (m2)

Plant

Operational

modification

(late 2013)

ECO-1 Unsaturated

bed

(4-8 mm)

Zeotuff

108 20 Unplanted bed Bypass (from

the septic tank)

ECO-2 Unsaturated

beds

(4-8 mm)

Zeotuff

1st bed : 85

2nd

bed: 60

1st

bed: 40

2nd

bed:

57

1st bed: Unplanted

2nd

bed: Planted

(Phragmites australis)

Step feeding

+ half saturated

(2nd

) bed


203

Reducing the constructed wetland (CW) footprint by means of a

Duplex-CW (O.148)

M Zapater-Pereyraa*

, H Ilyasa, JJA van Bruggen

a, PNL Lens

a

aUNESCO-IHE Institute for Water Education, P.O. Box 3015, 2601 DA Delft, The

Netherlands

*Correspondent author email: [email protected]

INTRODUCTION

The rapid population and urbanization growth in many cities around the globe have

prompted awareness towards appropriate use of open spaces. Many cities are lacking green

spaces and wastewater treatment facilities to satisfy their population needs. Constructed

wetlands (CW) offer both services (decentralized green area for the treatment of wastewater)

but the large space needed for this technology might be, in this type of cases, consider as a

disadvantage. Thus, to promote green growth and natural wastewater treatment, compact CW

should be developed as an alternative when land availability is limited. For that reason, this

study aims to develop and study a novel and compact system called the Duplex-CW

composed of two stack compartments: a vertical flow CW (VFCW) on top of a horizontal

flow filter (HFF).

METHODS

Three different configurations of Duplex-CW (area 0.24 m2, sand 1-2 mm) planted with

Phragmites Australis were assembled at a greenhouse in Delft, The Netherlands and were fed

with domestic wastewater twice a week (3 batches of 13 L each day). For all configurations,

the VFCW and HFF design was similar, 80 cm and 35 cm depth, respectively. However, the

hydraulic performance of the VFCW in each configuration differed: (i) A Fill and Drain

system (Fill&D), were the wastewater was retained for a period of 1 day, (ii) A Stagnant

batch system (StagB), were each batch of wastewater applied stayed in the system until the

following batch was applied, pushing the previous out (time between batches application was

about 6 h to 3 days) and (iii) A Free Drain system (FreeD), were the wastewater applied

could be discharged within a period of 1.5 h (due to the high hydraulic conductivity of the

material). Wastewater was applied on top of the VFCW and the effluent was discharged in

the HFF where it stayed there for 3-4 days, in the three configurations.

Low (15 gCOD m-2

d-1

, 8 m2 PE

-1), medium (28 gCOD m

-2 d

-1, 3.4 m

2 PE

-1) and high (37

gCOD m-2

d-1

, 2.7 m2 PE

-1) organic loading rate (OLR) was applied, in sequence, for a period

of 4 weeks each. The performance of the Duplex-CW for high OLR was tested with and

without artificial aeration (2 L min-1

) in the VFCW. Sampling was conducted once a week

(n=4 per organic load) and common physico-chemical parameters were tested (pH, EC, Eh,

DO, COD, BOD5, DOC, TSS, PO43-

-P, TP, NH4+-N, NO3

--N and TN) according to APHA,

2005. Organic matter humic, fulvic and protein-like compounds were analysed by measuring

the fluorescence excitation emission spectra of samples. These peaks locations were

considered in the fluorescence ranges as in Maeng et al. (2011).


Results reveal that all Duplex-CW systems could remove organic matter (TSS, COD,

BOD5 and DOC) to above 80%, despite the increment in organic load, however the Fill&D

system performed better than the FreeD and StagB systems probably due to the longer

retention time in the VFCW. The use of artificial aeration slightly increased the removal

efficiency of the systems; nevertheless, it did not show statistical differences when comparing


204

with the unaerated period. Benefits of aeration are not only immediate but long term

(reduction of solids accumulations, thus less clogging and long system life time), something

difficult to visualize in a four weeks experimental period. The use of aeration contributed to

totally remove protein-like compounds in all configurations while for humic-like compounds

the removal was enhanced (from 8-38% to 55-60% of peak intensity reduction). The high

reduction in protein-like is ascribed to possible increase in microbial activity due to increase

in DO under aeration, hence, biodegradation might have a leading role in reduction of

protein-like substances. However, small reductions of humic-like and fulvic-like compounds

suggest that adsorption could be the mechanism that dominated the reduction of these peaks.

The combination of an aerobic (VFCW) and anoxic (HFF) components had a major effect

in TN reduction, mainly in the Fill&D and FreeD systems. In all cases, the combination of

those two compartments always showed beneficial effects for the total performance of each

of the Duplex-CW as each compartment provided the treatment that the other could not, thus

increasing the treatment efficiency in the same space.

When comparing the Duplex-CW effluent quality to the EU standards (Steinel and

Margane, 2011), only the Fill&D system up to medium OLR met the guidelines for TSS,

COD, BOD5, TN and TP. The StagB system met the guidelines only for the first three

parameters, while the FreeD only for TSS and COD. Therefore, an area of 3.4 m2 PE

-1 can be

safely recommended for the Fill&D system instead of the common 5-10 m2

PE-1

used in

Europe (Babatunde et al., 2008). However, further research is needed to improve the

treatment efficiency under high OLR and thus reduce the area needed by a CW even further.

CONCLUSIONS

Fill&D system emerged as the best configuration when compared with StagB and FreeD

for organic matter and nutrients removal with and without aeration.

Artificial aeration enhanced the removal of organic matter and nutrients in all

configurations.

Duplex-CW can safely reduce the typical CW design of 5-10 m2 PE

-1 to 3.4 m

2 PE

-1, but

further research is needed to provide a more compact CW design.

REFERENCES

APHA, 2005. Standard methods for the examination of water and wastewater. 21st Edition,

American Public Health Association, Washington, D. C., USA.

Babatunde, A. O., Zhao, Y. Q., O’Neill, M. and O’Sullivan, B. 2008. Constructed wetlands

for environmental pollution control: A review of developments, research and practice in

Ireland. Environment International 34 (1): 116-126.

Maeng, S. K., Sharma, S. K., Abel, C. D. T., Magic-Knezev, A., and A my, G. L . 2011. Role

of biodegradation in the removal of pharmaceutically active compounds with different

bulk organic matter characteristics through managed aquifer recharge: Batch and column

studies. Water Research 45(16): 4722-4736.

Steinel, A. and Margance, A. 2011. Best management practice guideline for wastewater

facilities in karstic areas of Lebanon with special respect to the protection of ground-and

surface waters. Federal Ministry for Economic Cooperation and Development

(Bundesministerium für wirtschaftliche Zusammenarbeit und Entwicklung, BMZ).


205

French system


206

Results from a Data Base of Plants combining “French Type”

Vertical Flow CW with Waste Stabilization Ponds (O.158)

Stéphane TROESCH1, Bruno RICARD

2, Jean-Sylvain BOIS

3, Dirk ESSER

4

1 Epur Nature, 153 Avenue Maréchal Leclerc, 84 510 Caumont sur Durance, FRANCE,

[email protected]

2 SINBIO, 5 rue des Tulipes – BP5, 67 600 Muttersholtz, FRANCE, [email protected]

3 SATESE du Tarn et Garonne, 58 Avenue Marcel Unal, 82 000 Montauban, FRANCE, jean-

[email protected] 4

SINT, 73 370 La Chapelle du Mont du Chat, FRANCE, [email protected]

INTRODUCTION

Waste stabilization Ponds (WSP) have been built in France since the late ‘70’s to treat

wastewater from rural communities. A typical “French design”, based on recommendations

of IRSTEA (formerly Cemagref), is based on a first facultative pond of 6 m² per rural

habitant (based on an assumed load of 35 g BOD5 per rural habitant), followed by two

maturation ponds of 2.5 m² per habitant each (Lienard et al, 2004). There are today about

3000 of such WSP in France, which work without primary settlement upstream of the

facultative pond. However, increasing population and/or more stringent discharge limits

result in a rehabilitation or replacement of these ponds.

During the last years, Epur Nature, SINT, SINBIO and others companies have combined

these WSP with reed bed filters following different strategies and designs in order to improve

i) the treatment capacity of the plant, and/or ii) the effluent quality while limiting investment

costs. Also, existing ponds are kept – and sometimes even constructed - in between reed bed

filters with the aim to increase phosphorous and/or nitrogen removal, and sometimes

pathogens removal (Davis-Colley et al., 1999). This paper aims to present the results

observed on several configurations and to assess their interest.

METHODS

The combinations investigated in this study are the following: (1) 1st stage VFCW + WSP,

(2) 1st stage VFCW + WSP + 2nd stage VFCW and (3) 1st stage VFCW + 2nd stage VFCW

+ WSP with a recirculation (200% to 400% rate) as described in the following picture.

Fig. 1. Improving TN removal with recirculation; configuration (3)

The data were collected on different plants (characteristics described in the table below)

with the support of the local public technical assistance services for waste water treatment

plants (SATESE) who have assessed the removal efficiencies by 24-hour flow composite

sampling at different times of year (summer and winter) and for one year for the Nègrepelisse

plant with the configuration (2). As for as possible each stage of the treatment was evaluated

for COD, BOD, SS, TKN, N-NH4 and TP according to the French standard methods.

VFCW

1.2m²/PE

VFCW

0.8m²/PE

Ponds


207

Table 1. Characteristics of the data base plants.

VF + Pond

VF + Pond +

VF

VF+ VF +

Pond

Number of plants 6 4 1

Number of 24h composites sample 70 17 16

Autumn / Winter 30 8 0

Spring / Summer 40 9 16

Nominal Capacity (PE 600-4000 700 - 4000 1900

Hydraulic load (%) 55 +/- 30 64 +/- 17 42

Organic load (%) 45 +/- 25 58 +/-20 46

Age (yr) 2-15 0-5 2-5

Nominal Pond design (m²/PE) 5 +/- 1.2 3.5 +/- 0.6 2,6


The results show amongst others that it is possible to double the capacity only by adding a

classical first stage reed bed filter (1.2 m²/PE) to an existing pond system and guarantee the

same outlet quality (25 mg/L, 125 mg/L of filtered of BOD5 and COD respectively, 150

mg/L of SS). On the other hand, adding a second VFCW designed on a hydraulic load of 0.8

m/day on the filter in operation, downstream of the pond improves the outlet quality. In order

to meet both objectives, a combination of a classical “french designed” reed bed filter

(2m²/PE) and an intermediate WSP (5 m²/PE), is able to reach an outlet quality of 15 mg/L of

SS, 20 mg/L of BOD5, 70 mg/L of COD and 10 mg/L of TKN, with removal rates higher

than 70% in summer for total N. Nevertheless the recirculation (Fig 1) does not significantly

improve the removal efficiencies. Table 2. Treatment results of different configurations of VFCW and ponds

BOD5 COD SS TKN N-NO3 TN Pt

Mean

value (SD)

Mean

value (SD)

Mean

value (SD)

Mean

value (SD)

Mean

value (SD)

Mean

value (SD)

Mean

value (SD)

VF + P

Inlet 283,6 220,8 659,1 438,5 299,9 221,8 70,0 30,8 0,6 1,2 68,5 31,1 9,1 4,4

Winter 12,2 12,3 77,7 44,5 26,6 31,7 19,8 10,5 7,0 6,2 27,5 7,8 4,4 1,8

Summer 23,1 22,4 122,5 62,4 44,0 33,4 12,9 9,0 6,0 10,1 17,1 9,2 3,9 2,1

VF + P +

VF

Inlet 356,2 118,8 845,4 251,7 363,9 200,1 74,5 14,7 0,1 0,3 76,0 13,0 9,9 3,0

Winter 4,9 3,4 44,4 17,0 9,6 11,6 6,2 3,7 30,1 16,2 35,6 15,6 5,7 1,6

Summer 4,7 1,8 39,1 6,7 8,8 5,9 2,6 1,5 12,9 7,5 15,2 7,6 5,3 2,1

VF + VF

+ P

recirc

Inlet - - 746,3 274,6 367,6 24,3 61,6 31,9 0,1 0,0 61,6 31,9 9,3 2,3

Summer - - 54.7 14,7 7,8 3,3 5,7 2,7 27,0 5,2 32.2 9,8 5,0 0,6


208

CONCLUSIONS

It is clearly shown than the association of existing ponds (with at least 5m²/EH) with CW

improves either the capacity and/or the efficiency of the treatment plant. The other main

advantage consists in significant removal for total nitrogen and slightly for phosphorous

during summer which “classical” two stage VFCW do not achieve.

REFERENCES Davis-Colley, R. J., Donnison, A. M., Speed, D., Ross, C.M. and Nagels, J. W. (1999). Inactivation of faecal

indicator microorganisms in waste stabilization ponds: interactions of environmental factors with sunlight.

Water Research, 33(5), 1220-1230.

Racault Y., Boutin C. (2005). Waste Stabilisation Ponds in France. State of the art and recent trends. Water

Science and Technology, 51(12), 1-9.


209

Treatment performances of the French system, comparison of 2

stages (VF+ VF) to compact VF using 10 years of data (O.163)

J. Painga, A. Guilbert

a, V. Gagnon

b, F. Chazarenc

b

aJean VOISIN SAS, Les Charmilles, Z.A. les Poupinières, 37360 Beaumont-la-Ronce, France

([email protected]) bL’UNAM Université, Ecole des Mines de Nantes, CNRS, GEPEA, UMR 6144, 4 rue Alfred

6 Kastler, 44307 Nantes, France ([email protected])

INTRODUCTION

Vertical flow constructed wetlands to treat raw wastewater, also known as the French

system is nowadays largely developed in France. Since the early 1990s, Jean VOISIN

Company designed and constructed more than 470 plants from 20 to 2250 PE. Most of them

are made of two stages in series receiving raw domestic wastewater with a ratio of 2 m²/PE,

as recommended by IRSTEA (Molle et al., 2005). In 2008, a compact filter with expanded

schist was developed, named Ecophyltre®, with one single stage at 1.2 m²/PE, in order to

reduce food print and investment cost (Prigent et al., 2013).

In this paper, more than 10 years of performances recorded in both classical and compact

systems are compared.

METHODS

Treatment performances were determined by 24h composites samples collected by

SATESE (local technical services for wastewater treatment plants) or Jean VOISIN technical

assistance. Analyses for pH, COD, BOD, SS, TKN, N-NH4, N-NO3, TP, P-PO4 were

performed according to French standard methods. Data were selected for plants for more than

6 months old, hydraulic loads < 60 cm.d-1

(on first stage operated bed), and organic loads on

total surface was between 5 and 100 gCOD/m².d. The results from 83 classical systems (156

analysis) were compared to 13 compact systems (25 analysis).


Very good removal efficiencies have been obtained for SS, BOD, COD and TNK, with

mean percentage removal for the two stages (VF+VF) of 97%, 98%, 93% and 93%

respectively. The results with the compact filter Ecophyltre® showed mean percentage

removal of 91%, 94%, 87% and 81% respectively, with one single stage. Table 1. Characteristics of influent and effluent from “classical French” vertical reed beds (plant age > 6

months, HL < 60 cm.d-1

), expressed in mg/L.

pH SS BOD COD TKN N-NH4 N-NO3 TP P-PO4

Influent Mean 7,9 366 375 869 93 70 12 7

S.D. 0,4 248 182 479 27 22 5 2

1st stage

effluent

Mean 7,4 42 51 162 38 33 28 9 7

S.D. 0,4 33 46 94 17 16 27 3 2

2nd

stage

effluent

Mean 6,8 10 6 51 7 5 57 8 8

S.D. 1,1 9 4 20 6 6 24 3 3


210

Table 2. Characteristics of influent and effluent from compact vertical reed beds Ecophyltre® (plant age

> 6 months, HL < 40 cm.d-1

), expressed in mg/L.

pH SS BOD COD TKN N-NH4 N-NO3 TP P-PO4

Influent Mean 7,9 259 280 736 93 66 9 9

S.D. 0,3 176 144 376 43 31 4 7

1st stage

effluent

Mean 7,2 19 13 81 16 13 45 7 9

S.D. 0,4 13 8 35 14 14 19 3 7

The performances of compact filter Ecophyltre® are significantly better than the first stage

of classical models, as shown on figure 1. That could be explained by the efficiency of the

filtering materiel (two layers of expanded schist), as shown by Prigent et al. (2013).

CONCLUSIONS

The synthesis of more than 10 years or results showed that the VF+VF process was able to

achieve very low concentrations for COD, BOD, SS and TKN was proved. Removal

efficiencies were not affected by factors including hydraulic and organic loads, temperature

and/or age of treatment plants. The feedback of 5 years obtained with the compact VF

showed that this system allowed meeting French standards for capacities superior to 2000 PE

(COD < 125 mg/l, BOD < 25 mg/l, SS < 35 mg/l).

REFERENCES Prigent S., Belbeze G., Paing J., Andres Y., Voisin J., Chazarenc F. (2013) Biological characterization and

treatment performances of a compact vertical flow constructed wetland wih the use of expanded schist.

Ecological Engineering. 52:12-18.

Molle P., Lienard A., Boutin C., Iwema A. (2005) How to treat raw sewage with constructed wetlands : an

overview of the French systems. Water Science Technology. 51 (9):11-21.

Paing J., Voisin J. (2005) Vertical flow constructed wetlands for municipal wastewater and septage treatment in

French rural area. Water Sciences Technologie. 51 (9) : 145-155.

intensification and wetlands (aeration)...3baa, heathrow airport ltd, hounslow, middlesex, uk...

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