LOW-LEVEL PHOSPHORUS: SIMPLE TECHNOLOGY FOR COMPLIANCE

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1 July 24, 2014 LOW-LEVEL PHOSPHORUS: SIMPLE TECHNOLOGY FOR COMPLIANCE MWOA Annual Meeting Author Leon Downing, PhD,PE Co-Authors Eric Lynne, PE Mike Gerbitz, PE

2 Phosphorus Limits

3 Phosphorus Regulations Number of states with nutrient criteria increasing Number of States with Nutrient Criteria * 2016* Year (* denotes projection)

4 Phosphorus Regulations 100% 90% 80% 70% % of Major Dischargers with P Limit 60% 50% 40% 30% 20% 10% 0% Top 10 States

5 Phosphorus Regulations 100% 90% 80% 70% % of Major Dischargers with P Limit 60% 50% 40% 30% 20% 10% 0% Minnesota: Ranks 6th Top 10 States

6 Phosphorus Regulations 100% 90% 80% 70% % of Major Dischargers with P Limit 60% 50% 40% 30% 20% 10% 0% Minnesota: Ranks 6th Wisconsin: beginning implementation of lowlevel phosphorus limits Top 10 States Wisconsin: mg/l

7 What is Low-Level P? Secondary Effluent Filtration Effluent Brookfield, Wisconsin Phosphorus (mg/l) /30/13 7/31/13 8/1/13 8/2/13 Blue dots: secondary treatment to <0.4 mg/l Red dots: <0.1 mg/l achievable with filtration

8 What is Low Level P? Secondary Effluent Filtration Effluent Brookfield, Wisconsin Phosphorus (mg/l) /30/13 7/31/13 8/1/13 8/2/13 Blue dots: secondary treatment to <0.4 mg/l Red dots: <0.1 mg/l achievable with filtration Low Level P definition: Requires filtration, <0.3 mg/l

9 Low-Level Phosphorus Treatment

10 Low P Treatment Soluble P Particulate P

11 Low P Treatment Soluble P Chemical and biological conversion Particulate P Soluble P Particulate P

12 Low P Treatment Soluble P Chemical and biological conversion Particulate P Soluble P Particulate P Particulate P

13 Low P Treatment Soluble P Chemical and biological conversion Particulate P Soluble P Particulate P Particulate P Physical Separation

14 Low P Treatment Soluble P Chemical and biological conversion Particulate P Soluble P Soluble P Particulate P Particulate P Particulate P Physical Separation

15 Low P Treatment Soluble P Chemical and biological conversion Particulate P Soluble P Soluble P Particulate P Particulate P Particulate P Physical Separation or Ballasted Sedimentation

16 The Type of P is Important

17 The Type of P is Important Removed by solids separation OK

18 The Type of P is Important Removed by solids separation Removed by solids separation OK

19 The Type of P is Important Removed by solids separation Removed by solids separation Available soluble P OK

20 The Type of P is Important Removed by solids separation Removed by solids separation Available soluble P Very difficult to remove Trouble

21 Technologies Lower than 0.1 mg/l technologies Ultra Filtration Membranes ACTIFLO - Kruger, Inc. Densadeg - Infilco Degremont, Inc. AquaDAF - Infilco Degremont, Inc. Blue PRO - Blue Water Technologies, Inc. CoMag - Cambridge Water Technology DynaSand D2 Dual Filtration System - Parkson

22 Late 2012/Early 2013: Disc Filtration Manufacturers Offered Low Cost Pilot Testing to Prove Technology

23 Step 1 Get Soluble P Into Particulate P That Can Be Separated

24 Step 1: P into Flocs

25 Secondary effluent Step 1: P into flocs

26 Step 1: P into flocs Secondary effluent After ferric and polymer addition

27 Step 2 Remove the Flocs

28 Disc Filtration

29 Disc Filtration Polymer Ferric or Alum Coagulation Flocculation Filtration

30 Clean, enclosed installation Disc Filtration

31 Disc Filtration Clean, enclosed installation Inside-out flow pattern

32 Disc Filtration Clean, enclosed installation Inside-out flow pattern Influent to center of filters

33 Disc Filtration Clean, enclosed installation Inside-out flow pattern Influent to center of filters Effluent surrounds discs

34 Disc Filtration Pilot Units Sun Prairie Brookfield Stevens Point HOV Beloit Brookfield Beloit Sheboygan

35 Disc Filtration Pilot Unit

36 Disk Filter Pilot Results Effluent TP (mg/l) < mg/l achieved High chemical demand Molar Ratio (Me:P)

37 Disc Filter Pilot Results % increase in chemical from 0.1 to mg/l Effluent TP (mg/l) Molar Ratio (Me:P)

38 Pilot Results Show Need to Do Best You Can in Upstream Processes Goal: TP to filters <0.6 mg/l

39 Low-Level P is Achievable, How Might it be Controlled?

40 Control

41 Ferric or Alum Control

42 Control Ferric or Alum Ferric or Alum Polymer

43 Control Orthophosphate Analyzer Ferric or Alum Ferric or Alum Polymer

44 Control Orthophosphate Analyzer?? Ferric or Alum Ferric or Alum Polymer

45 Online Analyzer Feedback Trim Allows Upstream Optimization Goal: TP to filters <0.6 mg/l

46 Effluent Limit May Provide Opportunity to Right-Size Equipment

47 Right Sizing RWW Flow (mgd) % 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Percent Equal or Less Than

48 Right Sizing RWW Flow (mgd) Flows below 15 mgd 95% of the time 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Percent Equal or Less Than

49 Conservative Sizing

50 Right Sizing

51 Right Sizing

52 Takeaways

53 Takeaways Low P can be achieved (<0.1 mg/l)! Membrane not a necessity Cloth-media filtration and ballasted sedimentation Phosphorus speciation important Filtration pore size important Upstream treatment is critical High tertiary dosing rate (18 to 30 Me:P) Tight control on secondary treatment process May not need to meet low-level P limit at peak flows

54 Questions? Leon Downing, PhD, PE Donohue & Associates