2011 IWA Specialty Conference on: Natural Organic Matter: From Source to Tap and Beyond July 26-29, 2011

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1 2011 IWA Specialty Conference on: Natural Organic Matter: From Source to Tap and Beyond July 26-29, 2011 Wastewater NOM Composition Following Chemically Enhanced Pi Primary Treatment t and Microfiltration Graham Juby Adam Zacheis Jeffery Brown (OCSD) Edward Torres (OCSD)

2 Orange County, California Orange

3 Domestic wastewater contains a soup of organic compounds Typically y quantified by: -BOD - COD - Less frequently by TOC

4 The soluble portion of TOC in wastewater comes from many sources Drinking Water Soluble TOC in wastewater Human waste Household and Industrial Uses Biological activity in the sewer

5 Today the focus is on treated effluent TOC but that tells little about its makeup

6 OCSD owns and operates two large treatment plants that discharge to the Pacific Ocean

7 Treatment Plant No inch Outfall No inch Outfall No. 2 (5 miles) Pacific Ocean

8 In 2001, OCSD undertook an MF demonstration ti to produce effluent for ocean discharge Purpose: Determine whether MF treatment of primary effluent could produce a permeate suitable for ocean discharge

9 This followed successful pilot testing ti of the IMANS System Raw Wastewater Primary Treatment Microfiltration (MF) NF or RO UV/AOP GRRP Reuse Water Methane Methane UASB Anaerobic Digestion Sludge High Rate Anaerobic Digestion Concentrate/ Brine

10 This followed successful pilot testing ti of the IMANS System Raw Wastewater Primary Treatment Microfiltration (MF) Ocean Discharge Methane Anaerobic Digestion Sludge

11 A 200 gpm demonstration system was built for the project Screen Feed Tank CMF-S Cell Filtrate Tank Primary Effluent Splitter Box

12 MF demonstration plant included full-scale components

13 Completed demonstration plant (0.3 mgd)

14 MF plant was operated under constant t conditions for 4.5 months to generate data set Operating Parameter Value MF Production Rate (gpm) 194 Membrane flux (gfd) 13 Backwash frequency (minutes) 12

15 During 4.5 months of operation, samples were analyzed for 159 organic compounds 1. Up to 16 composite MF feed and product samples were analyzed compounds with drinking water MCLs were included 3. Regular discharge permit analyses were also carried out

16 Only 33 of the 159 compounds were detected no MCL exceeded 33 organic compounds detected in MF permeate Average TOC = 33.4 mg/l (N=23) All parameters were below discharge limits

17 Concentration of 20 compounds reduced across MF process Organic Compound MCL EDC Average Influent (µg/l) (N) Removal (%) 1,4-dichlorobenzene (10) 50 Butylbenzyl phthalate 0.9 (10) 100 Diethyl phthalate 4.13 (10) 59 Ethylbenzene (10) 24

18 The concentration of some compounds increased Organic Compound MCL EDC Average Influent (µg/l) (N) Increase (%) 2-fluorobiphenyl l 3.28 (10) 82 Benzonic Acid (10) 6 Bromodichloromethane 0.37 (10) 81 Bromoform ND (10) > 100 Dibromochloromethane 0.27 (10) 150 Total THMs

19 Although EDCs/PPCPs were not the focus 26 were included in the 159 total 7 were detected 19 were non-detect Typical target compounds (17β- Estradiol, Estrone, Testosterone t etc) were not included

20 So what does all this mean? Source Concentration (mg/l) TOC in MF permeate 33.4 Total of 33 compounds detected 0.47 Total of possible Typical EDCs/PPCP/CECs Drinking Water NOM ~1.5 TOC missing ~ 31.1

21 Tests for short chain fatty acids showed a high concentration of acetic acid, some propionic and butyric Concentration ti of Acetic Acid (mg/l)

22 Carboxylic acids account for about half of the missing i TOC

23 Primary effluent contains proteins and polysaccharides as well as EfOM and SMP

24 43% of MF permeate TOC passed through an NF membrane MF Permeate TOC = 51 mg/l NF Membrane ( Dalton Cut-Off) 29 mg/l (57%) 22 mg/l (43%)

25 NF speciation and literature point to high molecular weight compounds in missing TOC EfOM and SMP from recycle streams High MW polymers assumed to be mostly Proteins and Polysaccharides

26 Summary 1. All ocean discharge permit limits were met 2. OCSD has very strong source control program microconstituents removed across MF process 4. 12% increase in Total THMs observed 5. 46% of TOC is made up of carboxylic acids some solubilization and acidogeneis of carbohydrates, lipids, proteins has already occurred 6. Remaining 47% of TOC likely to be high molecular weight polymers of proteins and polysaccharides including EfOM and SMP 7. The concentration of CECs is low (< 1 mg/l) 8. Further work needed to improve quantification

27 2011 IWA Specialty Conference on: Natural Organic Matter: From Source to Tap and Beyond July 26-29, 2011 Wastewater NOM Composition Following Chemically Enhanced Pi Primary Treatment t and Microfiltration Graham Juby Adam Zacheis Jeffery Brown (OCSD) Edward Torres (OCSD)