All Those Fines! Installation of GAC into Deep Bed Contactors 1 Bonsteel1 Jane Ray Cantwell2 Roshni Jerrett2 Steven Radencich3 Kathleen Boyd3 Alton Williams4 2 3 4 Lakeview WTP 400 ML/d expansion – ‘OBM2’ OMB2 Process Overview Cl2 (Mussel) NaOH O3 Quench (Sodium Bisulphite) H2O2(Future) F,Cl2 Prescreening Ozone Contactors Lake Ontario BACCs UV Membranes Low Lift Pumps To Conventional and OBM1 facilities Backwash wastewater to Process Waste Treatment Facility Reservoir High Lift Pumps BACCs Parameter Length / Width Surface area per contactor GAC Media: Depth Effective Size Uniformity co-efficient Water Level over media Underdrains Value 8.2 m / 15 m 123 m2 2.5 m 1.35 – 1.45 mm 1.5 3.5 m AWI Phoenix stainless steel with 300 micron openings Laterals run lengthwise BACC Underdrains Air Scour Conduit Water CollectionBackwash Distribution Conduit 300 µm media retention slots GAC by the numbers 1538 Amount of GAC installed in m³ 780 Weight of GAC installed in tonnes 8.3 Weight of fines removed by scraping in tonnes 65 Total number of backwashes Installation Plan 6 Protect the underdrains z 6 Scrape the fines z 6 ~10 mm per lift Protect the downstream membranes z 6 3 ‘lifts’ (~0.8 m each) Ensure no GAC in BACC effluent Fit with existing operations z z z Aggressive schedule Long, high volume backwashes 21 other filters/contactors in service Conveying GAC Conveying GAC Scraping Fines Scraped Fines Waste bin Backwashing 6 # of backwashes determined as it progressed BACC media backwashing tracking sheet BACC No 1 10‐Oct 11‐Oct 12‐Oct 13‐Oct 14‐Oct 15‐Oct 16‐Oct 17‐Oct 18‐Oct 19‐Oct 20‐Oct 21‐Oct 22‐Oct 23‐Oct 24‐Oct 25‐Oct BACC No 2 BACC No 3 BACC No 4 BACC No 5 Comments 5 6 7 8 4 4 5 5 BACC 1 bags added 4 BACC 2 and 3 bags added 6,7 8,9 BACC 4 bags added 6 10 5 Jar Testing 6 6 6 6 Guessed at solids concentrations Needed to make fines Polymers (anionic, cationic, non-ionic) With and without alum Backwashing 6 Photos Backwashing 6 Photos Backwash Monitoring 6 Suspended solids & turbidity Backwash Monitoring BACC No. 1: Backwash No. 4 on October 8th 2013 (1st Backwash of 2nd Lift) 500 70 Low Rate Wash Starts High Rate Wash Starts 450 60 400 TSS TSS (mg/L) 300 40 Turbidity 250 30 200 150 20 100 10 50 0 0 0 2 4 6 8 Time From Start (min) 10 12 14 Turbidity (NTU) 50 350 Backwash Monitoring BACC No. 1: 8th and 13th Backwash- TSS Profile 70 High Rate Wash Starts Low Rate Wash Starts 60 TSS (mg/L) 50 40 Backwash 8 30 20 Backwash 13 10 0 0 1 2 3 4 Time From Start (min) 5 6 7 Wastewater Treatment 6 6 Very limited sewer capacity WTP’s WWTF effluent suspended solids limit: 15 mg/L (annual average) 6 Visible shoreline discharge Wastewater Treatment Lakeview Process Waste Treatment Facility- TSS Profile BACC No. 1: 2nd Backwash of the 2nd Lift on October 10th 2013 18 16 14 TSS (mg/L) 12 10 8 6 4 2 0 10:48 11:02 11:16 11:31 11:45 12:00 Time 12:14 12:28 12:43 12:57 Success! 2nd Forward Flush From BACC #1- Turbidity Profile 4 3.5 Turbidity (NTU) 3 2.5 2 1.5 1 0.5 0 0 2 4 6 Time From Start (min) 8 10 12 Summary 6 Co-operation & communication were crucial z 6 Operations staff, consultant, contractor, suppliers, owner Now have documentation Acknowledgements Maajida Darsot, Peel Region Tony Puim, OCWA Lorenzo Marsiglia, OCWA Scott Crawford, CH2M HILL AWI Norit Carbon
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