IMPLEMENTING A WASTEWATER TREATMENT FACILITY UPGRADE/ EXPANSION USING IFAS AT WEST HAVEN, CT

Transcription

1 28 January 2015 IMPLEMENTING A WASTEWATER TREATMENT FACILITY UPGRADE/ EXPANSION USING IFAS AT WEST HAVEN, CT MARIO FRANCUCCI

2 AGENDA Design Basis Project Challenges ConstrucEon Sequences and RestricEons Environmental RestricEons/Reviews Screening and Influent Pumping Primary SeOling Tanks AeraEon Tanks 2

3 AGENDA (CONT.) AeraEon Blowers ExisEng Secondary SeOling Tanks New Secondary SeOling Tanks Return AcEvated Sludge Pumping How is plant operaeng now? 3

4 DESIGN BASIS 4

5 DESIGN BASIS Average Day Maximum Month Flow (mgd) BOD (mg/l, ppd) 187 (15,070) 227 (19,750) TSS (mg/l, ppd) 191 (15,440) 296 (25,790) TKN (mg/l, ppd) 27 (2,184) 36 (3122) Total Nitrogen Waste Load AllocaEon August ppd

6 PROJECT CHALLENGES Design and implement a robust system Keep the plant operaeng and in compliance during construceon Small site footprint Minimize disturbance to Marine Wetlands 6

7 WEST HAVEN WPCF BEFORE AFTER 7

8 SITE PLAN Page - 8

9 ENVIRONMENTAL RESTRICTIONS/REVIEW SecEon 404 CWA, ACOE Coastal Zone Management Act Page /25/08

10 CONSTRUCTION SEQUENCING AND RESTRICTIONS WPCF conenuous operaeon One unit out of service at a Eme No work on exiseng primary clarifiers unel PC 1 work is complete No work on aeraeon unel all PC work completed and new SCs in service No work on exiseng SCs unel new SCs on line

11 SCREENING AND INFLUENT PUMPING Fine screens required for IFAS Unmanned facility requires simple and reliable screenings handling systems Required bypass pumping for construceon 11

12 MAIN PUMPING STATION UPPER LEVEL 12

13 MAIN PUMP STATION NEW MECHANICAL SCREENS 13

14 SLUICE TROUGH & GRINDER WASHER COMPACTOR 14

15 PRIMARY SETTLING TANKS FoundaEon required bolstering Repair cracked Tank No. 1 15

16 PRIMARY SETTLING TANKS BEFORE CONSTRUCTION 16

17 PRIMARY CLARIFIER REPAIR Tank 1 out of service since August 1994 Non- destruceve teseng Pulse echo teseng, 1995 Ground penetraeng radar, 2006 Not complete agreement between two teseng methods Sludge trough was not completely clean

18 PRIMARY SETTLING TANKS 1& 2 MICROPILE INSTALLATION 18

19 AERATION TANKS No room for new tanks, required a small footprint design Reliable and robust system required Readily implemented at this plant IFAS chosen 19

20 AERATION TANK BEFORE CONSTRUCTION 20

21 IFAS BASINS

22 IFAS BASIN (CONT.)

23 AERATION TANK MODIFICATION WORK 23

24 AERATION TANK INTERIOR WORK 24

25 AERATION TANK IFAS INSTALLATION 25

26 AERATION TANK IFAS 26

27 AERATION BLOWERS Average air requirement increased from approx. 8,000 to 11,800 SCFM Increased efficiency Limited building footprint 27

28 BLOWER ROOM BEFORE CONSTRUCTION 28

29 BLOWER ROOM POST CONSTRUCTION 29

30 EXISTING SECONDARY SETTLING TANKS Solids pass- through due to shallow depth Poor inlet design 30

31 EXISTING SECONDARY CLARIFIERS MODIFICATIONS PER FACILITIES PLAN New Inlet Baffles Aera4on Basin Effluent Aera4on Basin Effluent Floc Zone

32 Performed CFD Modeling to OpEmize Goals: - De- bogleneck clarifiers - Provide Good Inlet floccula4on, and - Diffusion into tank with energy dissipa4on CFD of Exis4ng West Haven Clarifier CFD of simple LA-EDI retrofit Inlet Diffuser and Relocation of Sludge Hopper Alternative 1 Alternative 2 3.7' LA-EDI 7.3' Flocculation 3' 2' 3' Baffled Diffusers 7.3' 3' 3' 3.7' No Scale Baffle to Protect Sludge Hopper Alternative 2 Plan 6' 6" 7 Sludge hopper relocated and equipped with manifold withdrawal

33 NEW SECONDARY SETTLING TANKS Designed to match available land area Doubled clarifier surface area 33

34 SECONDARY SETTLING TANK 7 & 8 EXISTING CONDITIONS 34

35 SECONDARY SETTLING TANK 7 & 8 TEMPORARY FILL 35

36 SECONDARY SETTLING TANK 7 & 8 SHEET PILING 36

37 SECONDARY SETTLING TANK 7 & 8 EXCAVATION 37

38 SECONDARY SETTLING TANK 7 & 8 INSTALLING PILES 38

39 SECONDARY SETTLING TANK 7 & 8 39

40 SECONDARY SETTLING TANK 7 & 8 40

41 RETURN ACTIVATED SLUDGE PUMPING Inaccurate sludge drawoff control Single pump for each pair of tanks Manual throoling of tank suceon lines Limited pump backup ExisEng sludge cross- collectors inoperable 41

42 EXISTING RETURN ACTIVATED SLUDGE PUMPING 42

43 RETURN ACTIVATED SLUDGE PUMPING

44 RAS PUMP STATION PRE CONSTRUCTION 44

45 RAS PUMP STATION POST CONSTRUCTION 45

46 HOW IS PLANT OPERATING NOW?

47 900 West Haven WPCF Effluent Total Nitrogen 800 TN Monthly Average (lbs/day)

48