Chemical Contaminants in Treated Wastewater including Groundwater Dimension

Transcription

1 Chemical Contaminants in Treated Wastewater including Groundwater Dimension Jörg E. Drewes (Germany) Chair, IWA Water Reuse Specialist Group Water Reuse in Agricultural Irrigation and Aquifer Recharge Brussels, June 2015

2 Chemicals of Emerging Concern Personal care products Pharmaceuticals Industrial Agricultural Natural Hormones Antibiotics Food additives and constituents (phytoestrogens, caffeine, sweeteners) Transformation products Inorganic constituents (boron, chlorate) Nanomaterials CECs at Large Unknown Unknowns Known Knowns Unknown Knowns

3 U.S. EPA Guidelines, 2012 No Federal U.S. regulations exist EPA released Guidelines for Water Reuse (1992, 2004, 2012) 25 states have developed their own regulations; 16 developed guidelines; 9 states have no regulations or guidelines In general: Limits for fecal coliform organisms (<200/100 ml), but no limits for parasites or viruses Guidelines do not advocate direct potable reuse and do not include recommendations for such use

4 U.S. EPA, Types of Reuse Urban Reuse (unrestricted reuse) Irrigation of public parks, golf courses, toilet flushing, recreational impoundments, car washing, fire protection Restricted access irrigation Areas where public access is prohibited (sod farms, tree nurseries, landscape impoundments) Agricultural Reuse 1) Food crops not for commercial processing (crops eaten raw) 2) Food Crops commercially processed 3) Non-Food Crops (pasture for milking animals) Construction uses Soil compaction, dust control, making concrete

5 U.S. EPA, Specified Types of Reuse continued Industrial Reuse Process water, cooling Environmental Reuse Wetlands, wildlife, habitat Groundwater Recharge Via spreading or injection into non-potable aquifers Indirect Potable Reuse GW recharge by spreading into potable aquifers GW recharge by injection into potable aquifers Augmentation of surface supplies

6 US EPA, Treatment Requirements Summary Prim. treatment GWR non-pr / spreading Prim. treatment Sec. treatment GWR non-pr / inj., Industr. R Prim. treatment Sec. treatment Disinfection Env.R, UrbanR, Restr. Areas, Agric.R (com.), LandscapeR, Constr.R, Cooling T. Prim. treatment Sec. treatment Filtration Disinfection Agric. R (non-com.), Rec. Imp., IPR (spreading) Prim. treatment Sec. treatment Filtration Disinfection Adv. treatment IPR (inj.,sw)

7 California Title 22: Definitions A) Disinfected secondary 23 recycled water oxidized (contains oxygen), NTU < 2 (average), NTU < 5 (no sample) disinfected (<23 TC/100 ml (median, 7d), < 240 TC/100 ml 1 sample / 30d) B) Disinfected secondary 2.2 recycled water oxidized (contains oxygen), NTU < 2 (average), NTU < 5 (no sample) disinfected (<2.2 TC/100 ml (median, 7d), < 23 TC/100 ml 1 sample / 30d) C) Filtered wastewater oxidized (contains oxygen), coagulated, clarified filtered, NTU < 2 (average), NTU < 5 (no sample) D) Disinfected tertiary recycled water = Filtered wastewater + chlorine disinfection (details on CT) or other process that provides 5 log removal of MS2

8 California Title 22 Use of Recycled Water A) Secondary 23 Irrigation of cementries, freeways, impoundments of landscape, mixing concrete B) Secondary 2.2 D) Filt. ww + disinfection Irrigation of food crops, parks, playgrounds, golf course Impoundments, unrestricted access, toilet flushing, fire fighting For Orchards, vineyards and fodder crops (except milking animals) lower quality is possible (primary effluent) Groundwater recharge: further requirements A) Secondary 23

9 Non potable Reuse: Urban Landscape Irrigation (Title 22)

10 CEC Uptake in Plants irrigated with Reclaimed Water =f(concentration and properties of CEC; irrigation practice; soil organic matter; plant tissue properties)

11 Groundwater Recharge with Reclaimed Water Potable reuse via surface spreading Potable reuse via direct injection

12 Groundwater Recharge Montebello Forebay, California Secondary treatment Tertiary filtration Disinfection 165,000 m 3 /day Surface Spreading Soil-Aquifer Treatment Disinfection 35% 65% from Stormwater Colorado River water

13 Surface Spreading Operation Conceptual Model Point of compliance (POC) POE Diluent: Stormwater Surface Water 2 Treatment 3 Treatment Point of exposure (POE) POE 6 months Diluent Na ve groundwater

14 Groundwater Recharge Groundwater Replenishment Project, California Secondary treatment Disinfection Microfiltration 265,000 m 3 /day Blending & Storage Degas/Lime UV-AOP Reverse Osmosis Injection

15 Subsurface Injection Conceptual Model

16 History of potable water reuse Montebello Forebay Spreading Grounds, Los Angeles County Sanitation Districts, California, USA (Old) Goreangab Water Reclamation Plant, Windhoek Water Factory 21, OCWD, California, USA Upper Occoquan Service Authority, Virginia, USA 1985 Hueco Bolson Recharge Project, El Paso, Texas, USA 1985 Clayton County, Georgia, USA 1993 West Basin Water Recycling Plant, California, USA 1999 Gwinnett County, California, USA 1999 Scottsdale Water Campus, Arizona, USA 2002 New Goreangab Water Reclamation Plant, Windhoek, Namibia 2002 Toreele Reuse Plant, Belgium 2003 NeWater Bedok, Kranji Singapore 2005 Alimitos Barrier, California, USA 2007 Chino Basin Recharge Project, California, USA Groundwater Replenishment Project, California, USA 2008 Loudon County, Virginia, USA 2008 Western Corridor, Queensland, Australia 2009 Arapahoe/Cottonwood, Colorado, USA NeWater, Changi, Singapore 2010 Prairie Waters Project, Colorado, USA Groundwater Replenishment Trial, Perth, Australia 2012 Dominguez Gap Barrier, California, USA 2012 Beaufort West, South Africa 2013 Big Spring, Texas, USA 2014 Wichita Falls, Texas, USA 2015 Groundwater Replenishment Project, California (Expansion), USA Drewes and Horstmeyer (2015), Recent Developments in Potable Reuse. Springer

17 Groundwater Recharge Regulations DPH E GW Replenishment Using RW May 30, 2014 TITLE 22, CALIFORNIA CODE OF REGULATIONS DIVISION 4, CHAPTER 3 ARTICLE 1. Definitions adopted June 18, 2014 (1) Adopt Section as follows: hour Composite Sample. 24-hour Composite Sample means an aggregate sample derived from no fewer than eight discrete samples collected at equal time intervals or collected proportional to the flow rate over the compositing period. The aggregate sample shall reflect the average source water quality covering the composite 24-hour sample period. NOTE: Authority cited: Sections 13521, and , Water Code; and Sections and , Health and Safety Code. Reference: Sections 13520, 13522, , 13523, , 13524, 13560, and , Water Code. (2) Adopt Section as follows: Added Tracer. Added Tracer means a non-reactive substance, with measureable characteristics distinctly different from the receiving groundwater, intentionally added to the water applied at a Groundwater Replenishment Reuse Project (GRRP) for the purpose of being a tracer such that the tracer can be readily identified in the groundwater downgradient of the GRRP to determine the underground retention time of the applied water. Groundwater replenishment surface application Groundwater replenishment subsurface application NOTE: Authority cited: Sections 13521, and , Water Code; and Sections and , Health and Safety Code. Reference: Sections 13520, 13522, , 13523, , 13524, 13560, and , Water Code.

18 Groundwater Recharge Regulations Best available technology Surface application: tertiary effluent, soil-aquifer treatment Subsurface application: tertiary effluent, microfiltration/ultrafiltration, reverse osmosis, UV-Advanced oxidation process Water quality standards Microbial contaminants Chemical contaminants => Alternative treatment options possible after demonstrating equal protection of public health

19 CA Groundwater Recharge Regulations Requirement Surface Spreading (SAT) Direct Injection (RO/UV-AOP) Recycled water contribution (RWC) Usually 20%; max. <50% >50% Pathogens >12-log enteric virus reduction; 10- log Giardia cyst reduction; 10-log Cryptosporidium oocyst reduction At least three different treatment processes >12-log enteric virus reduction; 10-log Giardia cyst reduction; 10-log Cryptosporidium oocyst reduction At least three different treatment processes Nitrogen Less than 10 mg N/L Less than 10 mg N/L prior to injection Total organic carbon (TOC) Indicator chemicals Priority pollutants; chemicals w/ notification levels; List of indicator chemicals TOC not exceeding 0.5/RWC after infiltration and percolation, but not influenced by dilution (<30 days) At least three indicator chemicals, demonstrate >90% reduction over 30 days of travel Quarterly (min. once a year) annually <0.25 mg/l TOC Surrogate and indicator chemical (>5) monitoring for performance assessment (0.5-log removal); 0.5-log 1,4-dioxane Quarterly (min. once a year) annually

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21 CECs Monitoring Scheme California Science Advisory Panel: - Distinguish between CECs with and without monitoring data - Need some toxicological information to derive monitoring trigger levels 21 Drewes, J.E. et al. (2013). Designing Monitoring Programs for Chemicals of Emerging Concern in Potable Reuse What to include and what not to include? Water Science and Technology 67(2)

22 Performance Goals - Chemical contaminants (Performance-based) Constituent/ Parameter Relevance/Indicator Type/Surrogate Monitoring Trigger Level (micrograms/liter) 1 Expected Removal Differential (%) GROUNDWATER RECHARGE REUSE - SURFACE APPLICATION 2 17β-estradiol Health Caffeine Health & Performance 0.35 >90 NDMA Health Triclosan Health Gemfibrozil Performance -- >90 Iopromide Performance -- >90 DEET Performance -- >90 Sucralose Performance -- <25 Ammonia Surrogate -- >90 TOC Surrogate -- >30 Nitrate Surrogate -- >30 UV Absorption Surrogate -- >30 GROUNDWATER RECHARGE REUSE - SUBSURFACE APPLICATION 3 17β-estradiol Health Caffeine Health & Performance 0.35 >90 NDMA Health & Performance , >80 4 Triclosan Health DEET Performance -- >90 Sucralose Performance -- >90 Electrical Conductivity Surrogate -- >90 TOC Surrogate -- >90 California Recycled Water Policy, 2012

23 Assuring Water Quality Reuse treatment trains should be designed to include robustness and reliability Reclamation facilities should develop monitoring and operational plans to respond to variability, equipment malfunctions, and operator error Robustness Reliability Retention and blending requirements for quality assurance are expected to become less significant as monitoring and attenuation technologies improve

24 Evaluating the Risks in Context Potable reuse via surface spreading De facto reuse (~5%) Potable reuse via direct injection

25 Risk Exemplar Results: Pathogens 1 Norovirus 0.1 Adenovirus Salmonella Cryptosporidium Relative risk (scenario 1 = 1) ** * The risks for Salmonella and Cryptosporidium in Scenario 3 were below the limits that could be assessed by the model. Scenario 1 de facto reuse Scenario 2 SAT Scenario 3 MF/RO/UV

26 Risk Exemplar Results: Chemicals

27 Australian Water Recycling Guidelines (Phase 2) Phase 1: non-potable uses (2006) Phase 2: potable uses (2008) Requires serious consideration of chemical hazards Requires consideration of hazardous events Risk management framework Hazard identification Risk assessment Preventative measures

28 Thank you! Jörg E. Drewes