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Effect of Ferric Chloride Addition and Holding Time on Gravity Belt Thickening of Waste Activated Sludge
Author(s) -
Kozak Joseph,
Patel Kamlesh,
Abedin Zainul,
Lordi David,
O'Connor Catherine,
Granato Thomas,
Kollias Louis
Publication year - 2011
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143010x12780288628417
Subject(s) - thickening , ferric , activated sludge , chloride , specific gravity , chemistry , waste management , environmental science , sedimentation , wastewater , environmental engineering , mineralogy , geology , inorganic chemistry , engineering , sediment , organic chemistry , polymer science , paleontology
Phosphorus removal using ferric chloride (FeCl 3 ) addition was demonstrated at the Egan Water Reclamation Plant. Concurrently, sludge thickening performance problems occurred in the gravity belt thickeners (GBTs). Blinding problems and polymer demand change were attributed to FeCl 3 and long sludge holding times. Laboratory tests were conducted to gain insight to the GBT problems. Sludge holding time effects before polymer conditioning and thickening and prolonged contact of the solids with FeCl 3 were evaluated via modified time‐to‐filter and blinding tests developed for this study. The tests assessed the sludge filterability under polymer and FeCl 3 conditioning treatments and varying sludge holding and FeCl 3 contact times. It was determined that fresh sludge was the easiest to thicken compared with sludge stored for any length of time. The FeCl 3 improved thickening; however, when both the FeCl 3 and polymer were used as conditioners, higher FeCl 3 concentrations resulted in thickening inhibition compared with polymer alone.