Reclaimed Water Current Research and Emerging Contaminants

Transcription

1 Reclaimed Water Current Research and Emerging Contaminants May 25, :30 am -12:00 pm Tina Hanson, P.E. Enrique Vadiveloo, P.E. Hazen and Sawyer, P.C 1 1

2 Drivers for Advanced Technologies As water resources are stressed, utilities often forced to consider less pristine sources Wastewater reuse Polluted sources EPA regulations Public pressure 2

3 Examples of Current Research Agency Project Project Title Project Summary/Objective WaterRF 4260 EDC/PPCP Benchmarking and Monitoring Strategies for Drinking Water Utilities WERF U3R10 Developing a Standardized Protocol for Assessing the Biodegradability of Trace Organic Contaminants The project will develop, justify, and document statistical tools and protocols that water utilities can use to design and implement monitoring programs for endocrine-disrupting compounds (EDCs) and pharmaceuticals and personal care products (PPCPs) within a watershed. The project will provide data that can be used by design engineers and utility managers for improving TOrC removal in facilities using biological treatment processes. In particular, the project will develop a methodology and a guideline as to how to best measure reliable TOrC biodegradation kinetics. 3

4 Examples of Current Research Agency Project Project Title Project Summary/Objective WRRF Use of Ozone in Water Reclamation for Contaminant Destruction WRRF Pilot-Scale Oxidative Technologies for Reducing Membrane Fouling Potential in Water Reuse and Drinking Water Treatment Systems This project evaluates the potential of ozone for contaminant oxidation in a variety of reclaimed water qualities and in combination with a variety water of treatment processes. This project will investigate the potential for pilot-scale oxidative technologies placed upstream of membrane treatment to reduce the organic fouling of NF and RO membranes during drinking water treatment, reuse, and desalting applications. Additionally, mechanisms associated with organic fouling with and without oxidative pre-treatment will be investigated along with relative energy costs and carbon footprints associated with each technology. 4

5 Examples of Current Research Agency Project Project Title Project Summary/Objective WRRF Guidance for Implementing Water Reuse in New Buildings and Developments to Achieve LEED Sustainability Goals This project will create a useful Guidance Document that outlines the critical information that developers and architects need to make informed decisions about recycled water implementation in their projects. 5

6 A Recurring Theme Treatment processes either remove or change chemicals in water Removal is good but leaves you with a concentrated waste stream Change is good but leaves you with questions about what remains in the water 6

7 Three Reclaimed Water Case Studies Lessons Learned Plantation Pilot (Surface Water Recharge) 7 Hollywood SRWWTP Water Reclamation Project (Brackish Aquifer Recharge) Miami-Dade SDWWTP Water Reclamation Project (Groundwater Recharge)

8 Background 8

9 SE Florida s Hydrogeology Is Unique 9

10 Regulatory Drivers for Reuse Regional Water Availability Rule (Demand Not Met) Ocean Outfall Rule 60% Reuse Requirement (150 mgd of reuse needed) 10

11 Biscayne water availability capped by the Regional Water Availability Rule DNM DNM = Demand Not Met 11

12 Many of the Options Available to Meet the DNM Involve Reuse Demand Management New Source Water Conservation Landscape irrigation with reclaimed water Captured stormwaters (C-51) Aquifer Storage and Recovery (ASR) Floridan Aquifer Utilization Seawater utilization Biscayne Aquifer recharge with full treatment reclaimed water 12

13 Ocean Outfall Rule Review Signed into Law by the Governor on June 30, 2008 Elimination of Ocean Outfall (except for back-up discharges) December 31, 2025 Existing outfalls capped at capacity as of July 1, 2008 Ocean Outfall Nutrient Reduction by December 31, 2018 > 60% of Outfall Flow to Reuse by December 31,

14 This rule affects much of Southeast Florida Over 3 million people are served by outfalls 150 Mgd of Reuse Required 14

15 Ocean Outfall Rule Reuse Options Residential Areas Options: Biscayne Aquifer Recharge Floridan Aquifer Recharge Irrigation & process water uses: Large areas (parks, golf courses, etc.) Residential Industrial Cooling towers Floridan Recharge 15

16 In SE Florida Irrigation is Limited Due to High Chlorides and Urbanization Chlorides (salt) too high to use Urbanization drives cost up Ft. Lauderdale G.T. Lohmeyer WWTP Broward County NRWWTP Typical Effluent Chloride Concentration Miami-Dade NRWWTP Facility / Rating (mgd) Effluent Chlorides (mg/l) Miami-Dade CDWWTP Hollywood SRWWTP Broward County NRWWTP / Ft. Lauderdale CRWWTP / Miami-Dade SDWWTP Hollywood SRWWTP / Miami-Dade NDWWTP / Miami-Dade CDWWTP / Miami-Dade SDWWTP /

17 Case Studies 17

18 Miami-Dade SDWWTP Water Reclamation Plant Plantation Pilot (Surface Water Recharge) 18 Hollywood SRWWTP Water Reclamation Project (Brackish Aquifer Recharge) Miami-Dade SDWWTP Water Reclamation Plant (Groundwater Recharge)

19 Background Miami Dade Needed Additional Biscayne Aquifer Withrawals 19

20 Challenges - SDWRF Key Treatment Limits Stringent effluent limits NH3-N < 0.5 mg/l (single max.) TP = 0.02 mg/l (annual average) Primary and Secondary Drinking Water Standards SDWWTP is a pure ox plant with high effluent ammonia concentrations. Upfront BNR was not economically feasible 20

21 Challenges Currently There Are No Emerging Contaminant Regulations in Florida, But the Public Will Demand Removal 21

22 Approach Regulators Looked at Orange County, CA Groundwater Replenishment System for Guidance Chemical Log Reduction per Unit of Power Draw Required Same Treatment as Orange County MF/RO/UV-AOP Required Similar Emerging Contaminant Limits N-Nitrosodimethylamine (NDMA) < 0.7 ng/l 1,4-dioxane < 3.2 ug/l TCE UV-Oxidation UV-Photolysis 1,4-Dioxane NDMA ppm H2O2 14 ppm H2O2 7 ppm H2O2 14 ppm H2O2 7 ppm H2O2 14 ppm H2O2 22

23 Approach A Six Month Pilot Was Required to Demonstrate Meeting Effluent Criteria 23

24 Approach - Several Manufacturers Were Piloted to Meet Specific Performance Criteria GE-Zenon Pall Calgon Trojan Siemens CP Kruger-Norit Siemens CS RO System 24

25 Results - The MF/RO/IX/UV-AOP Process Scheme Met Effluent Criteria Effluent Sample Parameter Goal/Limit Severn Trent Filtration Units Combined MF Units 3 Stage RO Unit UV-AOP Unit Trojan Ion Exchange Purolite Avantech BP Chlorination TSS FOG Turbidity Turbidity SDI TDS Ammonia TP 5.0 mg/l 5.0 mg/l 5.0 NTU 0.5 NTU 2.0 Units 50 mg/l 0.5 mg/l? ug/l Average Concentration 1.24 mg/l 0.74 mg/l 1.27 NTU NTU 0.57 Units 18.7 mg/l 2.25 mg/l 5.5 ug/l Remarks Consistently meets goals/limits Consistently meets goals/limits Consistently meets goal/limit Cannot consistently meet goal/limit Goal/limit not defined NDMA ug/l ug/l Consistently meets goal/limit Ammonia Ammonia NDMA 0.5 mg/l 0.5 mg/l ug/l mg/l mg/l mg/l >70 ug/l Cannot consistently meet goal/limit Consistently meets goal/limit Approaches goal/limit Cannot meet goal/limit 25

26 Lessons Learned 26 RO alone was not sufficient to meet 0.5 mg/l ammonia limit. Ion exchange can be a viable option for ammonia removal NDMA was formed during break point chlorination. Addition of chlorine to main plant should be monitored Design of project complete. Construction on hold due to the economic situation Approximately $250M for 21 mgd of reuse

27 Plantation Advanced Wastewater Treatment Pilot Plantation Pilot (Surface Water Recharge) 27 Hollywood SRWWTP Water Reclamation Project (Brackish Aquifer Recharge) Miami-Dade SDWWTP Water Reclamation Plant (Groundwater Recharge)

28 Background - WWTP Located Near Canal that could Recharge the Biscayne Aquifer Plantation WWTP East Holloway Canal Central Wellfields East Wellfields 28

29 Challenges - There Are Several Challenges with Surface Water Recharge 29

30 Approach Two treatment schemes piloted: MBR Scheme 30

31 Approach Two treatment schemes piloted: Conventional Scheme 31

32 Results Both Pilots Met Stringent TN & TP Limits 32

33 Concentration (ng/l) Results Emerging Contaminants RO Influent Concentrations 33

34 Concentration (ng/l) Results - Most Were Removed by RO Membranes 34

35 Results - RO Permeate Can Be Toxic RO permeate is too clean RO restabilization/remineralization Added salts and minerals How would this work full scale? Dilution Mixing zone Table 1. RO Effluent Stabilization Recipe Ingredient Final Concentration (mm) CaCl K 2 SO MgSO NaHCO Na 2 PO Na 2 CO Reference: WERF Report 01-HHE-4A (Schelenk et al., 2007) Water Flea 35

36 Lessons Learned The pilot demonstrated to meet stringent nutrient limits at different test conditions RO membranes are necessary for surface water discharge due to stringent TP limits (0.02 mg/l) Almost all microconstituents were removed by RO system RO permeate could be toxic to aquatic organisms. Restabilization/re-mineralization is necessary 36

37 Hollywood SRWWTP Brackish Aquifer Recharge Plantation Pilot (Surface Water Recharge) 37 Hollywood SRWWTP Water Reclamation Project (Brackish Aquifer Recharge) Miami-Dade SDWWTP Water Reclamation Plant (Groundwater Recharge)

38 Background 24 MGD of Reuse Required Southern Regional Wastewater Treatment Plant 60 Ocean Outfall Ocean Outfall Rule Close Outfall by Dec % of Flow to Outfall Must be Reuse 24 MGD of Reuse Needed 38

39 Challenges - Reuse Options Are Limited Large User Spray Irrigation Biscayne Aquifer Recharge High Chlorides Floridan Aquifer Recharge Nutrient Limits 39 Uncertainties

40 Challenges Regulators Want Emerging Contaminants Removal But There Are No Clear Requirements 40 Parameter FDEP Broward County MDWASD CBOD 5 20 mg/l 1 5 mg/l 2 20 mg/l 1 COD mg/l TSS 5 mg/l 2 5 mg/l 2 5 mg/l 2 Nitrate (as N) 10 mg/l 2 10 mg/l 2 10 mg/l 2 Nitrite (as N) 1 mg/l 2 1 mg/l 2 1 mg/l 2 Nitrate + Nitrite (as N) mg/l Total Nitrogen 10 mg/l mg/l 1,4 Phosphate (as P) 0.01 mg/l 2 Chloride mg/l Emerging Contaminants??? 1. Annual Average 2. Maximum Single Sample 3. Variances may be obtained for ammonia concentration exceeding 10 mg/l

41 Approach - Pilot Alternative Technologies To Provide Similar Emerging Contaminants Oxidation/Treatment as Best Available Technology Microfiltration Reverse Osmosis AOP Secondary or Tertiary Effluent Backwash Waste Concentrate Recharge 41

42 Results and Lessons Learned 42

43 A Recurring Theme Two classifications for advanced treatment processes Oxidation processes destroy contaminants, but leave you with unknown byproducts Removal processes separate contaminants from water, but leave you with a concentrated residual Advanced oxidation capable of degrading trace organics Destroy contaminants, and also destroy activity of contaminants Not all AOPs are equally effective for all contaminants We must evaluate the energy costs! 43

44 High pressure membranes provide effective barriers against emerging contaminants Capable of removing contaminants to the limits of detection Multiple barrier approaches provide the most overall benefit Lots of ways to get rid of micro-pollutants, but at what cost?? 44

45 Final Thoughts As analytical detection continues to improve, we will find new emerging contaminants in drinking water. Advanced treatment processes will effectively treat EDCs and pharmaceuticals, but more than that, they can be studied in such a way that we understand whether they will be effective in treating the next set of emerging contaminants. How can advanced treatment processes be beneficial as you aim to do more than what the public asks to protect health? 45

46 Questions? 46