An Add On Nitrifying MBR As Effluent Polishing Technique For Ee2

+

ISEST 2009, Shanghai, June 4, 2009

Bart De Gusseme

B. Pycke, T. Hennebel, A. Marcoen, S. E. Vlaeminck, H. Noppe, N. Boon, W. Verstraete

Laboratory of Microbial Ecology & Technology, Ghent University, Belgium

An add-on nitrifying membrane bioreactor as

effluent polishing technique for 17α-ethinylestradiol

Bart De Gusseme An add-on MBR as effluent polishing technique for 17α-ethinylestradiol ISEST

2009, Shanghai, June 4, 2009

+Introduction

Municipal WWTPs = constructed for efficient removal of organic nutrients (g/L)

Conventional WWTPs ≠ designed for the removal of micropollutants such as PPCP (μg – ng/L)

Since discovery of feminization of male fish, growing concern about endocrine disrupting compounds (EDCs)

2

Bart De Gusseme An add-on MBR as effluent polishing technique for 17α-ethinylestradiol ISEST 2009, Shanghai, June 4, 2009

+17α-ethinylestradiol

Estrogens are the most studied and known EDCs

17α-ethinylestradiol (EE2) is the main contributor to estrogenic activity in WWTP effluents

(Johnson & Williams, 2004; ES&T, 38: 3649-3658)

3


+Need for effluent post-treatment EE2 present in WWTP effluents

1-6 ng/L

(Cargouet et al., 2004; Sci Tot Environ, 324: 55-66; Vethaak et al., 2005; Chemosp, 59: 511-524; Johnson et al., 2007; Environ Poll, 147: 194-202)

up to 106 ng/L(Clara et al., 2005; Wat Res, 39: 97-106)

EE2 in receiving surface waters up to 20 ng/L

(Barel-Cohen et al., 2006; J Environ Manag, 78: 16-23)

4


+


Need for effluent post-treatment WWTP effluent polishing

Techniques Chlorination, UV photolysis, ozonation Activated carbon Membrane filtration

Problems High costs Final products may still exert endocrine activity Or are potentially toxic/carcinogenic

Need for alternative and sustainable

WWTP effluent polishing techniques

+Nitrifying cultures and EE2 removal Researchers demonstrated the degradation of EE2

by nitrifying sludge (Vader et al., 2000; Chemosp, 41: 1239-1243)

by the AOB Nitrosomonas europaea

(Shi et al., 2004; Wat Res, 38: 2323-2330)

The enzyme ammonium monooxygenase (AMO) can mediate an EE2/NH4

+ cometabolism (Yi & Harper, 2007; ES&T, 41: 4311-4316)

Shi et al. (2004) suggested that AOBs initially degrade EE2 to intermediates These intermediates serve as substrate for heterotrophs

6


+Research questions

1. Can we use a commercially available nitrifier enrichment culture (NEC) for biological EE2 removal?

2. What is the role of sorption and nitrification in the mechanism?

3. Can we use the NEC in a MBR system for continuous removal?

Commercially available NEC (ABIL)(Grommen et al., 2002; Aquacult, 211: 115-124; LabMET)

AOB: NitrosomonasNOB: Nitrobacter & NitrospiraHeterotrophic strains

7


+1. Batch incubation experiments Incubation of NEC in minimal (Stanier) medium

0.75 g VSS/L 750 μg EE2/L 52.5 mg NH4

+-N/L

Incubation of NEC in WWTP effluent (Ossemeersen, Gent) Containing 1.5 mg NH4

+-N/L

Spiked with 750 μg EE2/L

Incubation of heat-treated NEC in minimal medium 121 °C, 30 min To test the role of sorption

Negative (biomass-free) control in minimal medium

8


+1. Batch incubation experiments NEC in WWTP effluent

9 μg EE2/g VSS.h

NEC in minimal medium9 μg EE2/g VSS.h

Heat-treated NEC

Biomass-free control

NH4+-N : 52.5 < 2 mg/L

9


+


Take home message:

1. Batch incubation experiments

Biological EE2 removal by NEC in WWTP effluent possible

The role of sorption is limited

Highest removal rates at low NH4+-N conc. : competition?

+2. Mechanism

Role of nitrification?

AMO can mediate EE2/NH4+ cometabolism

(Yi & Harper, 2007; ES&T, 41: 4311-4316)

Allylthiourea (ATU) is a specific inhibitor of AMO (Hooper & Terry, 1973; J Bacteriol, 115: 480-485)

Incubation of NEC in minimal medium Without ATU With 50 mg ATU/L

11


+2. Mechanism

96 1 % removal without ATUComplete nitrification

38 1 % removalwith ATUNo nitrification

Nitrification is driving force for EE2 removal

12


EE2 removal---- Nitrate production

+3. Continuous EE2 removal in MBRA. Reactor design

Influent (tap water containing EE2)

Plate membranes

Effluent

Gas diffuser

Sprue with vacuum

Air

13


+3. Continuous EE2 removal in MBRB. Operational parameters MBR operated at different HRTs, NH4

+-N influent concentrations, EE2 loading rates

Prevention of biofouling of membranes Low VSS concentration (0.75 g VSS/L) Discontinuous pumping allows relaxation periods

14


100 μg/L

83 ng/L

+3. Continuous EE2 removal in MBRC. Reactor performance


15

High EE2 removal efficiency at both μg and ng/L level

Flux (7 L/m2.h) comparable with practice (Hoinkis & Panten, 2008; Chem Eng Process, 47: 1159-1164)

Optimal performance at ± 1 mg NH4+-N/L input

+

Discharge tosurface waters

Add-on MBR with NEC

Future perspectives16


European Directive 91/271/EEC : Total nitrogen in urban WWTP effluent < 10 mg N/L

Wastewater Treatment Plant

Effluent Activated

sludge

If necessary,dosage of NH4

+-Nto 1 mg/L

+Conclusions

Biological removal of EE2 by a NEC is possible Both in minimal medium and in WWTP effluent (batch) Continuously in a nitrifying MBR Maximum removal rates at minimal ammonium concentrations,

suggesting a competition between NH4+ and EE2 for enzymatic

removal

Nitrification is driving force in EE2 removal

This add-on MBR technology offers perspectives for continuous effluent polishing Low VSS concentrations prevents biofouling of the membranes Minimal ammonium-N input minimal nitrate-N output


17

+Acknowledgements

Bart De Gusseme (Aspirant), Tom Hennebel (project no. 7741-02) and Siegfried E. Vlaeminck (Aspirant) are supported by the Fund of Scientific Research (FWO)-Flanders

Benny Pycke is supported by a PhD grant (IWT-SB/53360) of the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT)

This study was part of the EU Neptune project (ContractNo. 036845, SUSTDEV-2005-3.II.3.2), which was financed by the EU Commission and the Sixth Framework (FP6-2005-Global-4).


18

+ B. De Gusseme, B. Pycke, T. Hennebel, A. Marcoen, S. E. Vlaeminck, H. Noppe, N. Boon & W. Verstraete

Biological removal of 17α-ethinylestradiol by a nitrifier enrichment culture in a membrane bioreactor. Water Research, 43, 2493-2503.

[email protected]


An Add On Nitrifying MBR As Effluent Polishing Technique For Ee2

Business

Transcript of An Add On Nitrifying MBR As Effluent Polishing Technique For Ee2