title: Effect of ferric chloride addition and holding time on gravity belt thickening of waste activated sludge.
abstract: Phosphorus removal using ferric chloride (FeCl3) 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 FeCl3 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 FeCl3 were evaluated via modified time-to-filter and blinding tests developed for this study. The tests assessed the sludge filterability under polymer and FeCl3 conditioning treatments and varying sludge holding and FeCl3 contact times. It was determined that fresh sludge was the easiest to thicken compared with sludge stored for any length of time. The FeCl3 improved thickening; however, when both the FeCl3 and polymer were used as conditioners, higher FeCl3 concentrations resulted in thickening inhibition compared with polymer alone.
authors: Metropolitan Water Reclamation District of Greater Chicago, Research and Development Department, Cicero, Illinois 60804, USA. joseph.kozak@mwrd.org
authors: Joseph
authors: J
authors: Kozak
authors: Kamlesh
authors: K
authors: Patel
authors: Zainul
authors: Z
authors: Abedin
authors: David
authors: D
authors: Lordi
authors: Catherine
authors: C
authors: O'Connor
authors: Thomas
authors: T
authors: Granato
authors: Louis
authors: L
authors: Kollias
mesh_terms: D019149:Bioreactors; D002712:Chlorides / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry*; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*; D014867:Water
chemical_list: D002712:Chlorides; D005290:Ferric Compounds; D012722:Sewage; D014867:Water; C024555:ferric chloride