title: Compact secondary treatment train combining a lab-scale moving bed biofilm reactor and enhanced flotation processes.
abstract: High-rate wastewater processes are receiving a renewed interest to obtain energy positive/efficient water resource recovery facilities. An innovative treatment train combining a high-rate moving bed biofilm reactor (HR-MBBR) with an enhanced flotation process was studied. The two objectives of this work were 1) to maximize the conversion of soluble organics to particulate matter in an HR-MBBR and 2) to maximize the particulate matter recovery from the HR-MBBR effluent by green chemicals to enhance biogas production by anaerobic digestion. To achieve these objectives, lab-scale MBBRs fed with synthetic soluble wastewater were operated at organic loading rates (OLRs) between 4 and 34 kg COD m-3reactor d-1corresponding to hydraulic retention times (HRTs) between 6 and 54 min. Colloidal and soluble chemical oxygen demand (COD) removal efficiency in the HR-MBBR increased with HRT to reach a plateau of 85% at an HRT longer than 27 min. Carrier clogging observed at an OLR higher than 16 kg COD m-3d-1(HRT < 13 min) resulted in about 23% loss in colloidal and soluble COD removal efficiency. Thus, the recommended parameters were between 22 and 37 min and between 6 and 10 kg COD m-3d-1for the HRT and the OLR, respectively, to maximize the conversion of soluble organics to particulate matter. Total suspended solids (TSS) recovery of 58-85% and 90-97% were achieved by enhanced flotation using green and unbiodegradable chemicals, respectively, corresponding to a TSS effluent concentration below 14 and 7 mg TSS/L. Among the synthetic polymers tested, a high molecular weight and low charge density cationic polyacrylamide was found to give the best results with less than 2 mg TSS/L in the clarified effluent (97% TSS recovery). Green chemicals, although performing slightly less for solids separation than unbiodegradable chemicals, achieved a mean TSS concentration of 10 ± 3 mg/L in the clarified effluent.
authors: Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, 2900, Edouard-Montpetit Boulevard, Montreal, Quebec, H3T 1J4, Canada; Kemira Water Solutions Canada Inc., 3405, Marie-Victorin Boulevard, Varennes, Quebec, J3X 1P7, Canada. Electronic address: ext.catherine.brosseau@kemira.com.
authors: Catherine
authors: C
authors: Brosseau
authors: Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, 2900, Edouard-Montpetit Boulevard, Montreal, Quebec, H3T 1J4, Canada; SAP Canada Inc., 111, Duke Street, Suite 9000, Montreal, Quebec, H3C 2M1, Canada. Electronic address: bettina.emile@sap.com.
authors: Bettina
authors: B
authors: Émile
authors: Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, 2900, Edouard-Montpetit Boulevard, Montreal, Quebec, H3T 1J4, Canada; WSP Canada Inc., 2525, Daniel-Johnson Boulevard, Office 525, Laval, Quebec, H7T 1S9, Canada. Electronic address: marc.andre.labelle@wspgroup.com.
authors: Marc-André
authors: MA
authors: Labelle
authors: Veolia Water Technologies Canada Inc., 4105, Sartelon Street, Saint-Laurent, Quebec, H4S 2B3, Canada; Cegep Saint-Laurent, 625, Sainte Croix Avenue, Montreal, Quebec, H4L 3X7, Canada. Electronic address: edlaflamme@cegepsl.qc.ca.
authors: Édith
authors: É
authors: Laflamme
authors: EnviroSim Associates Ltd., 175, Longwood Road South, Suite 114A, Hamilton, Ontario, L8P 0A1, Canada. Electronic address: dold@envirosim.com.
authors: Peter L
authors: PL
authors: Dold
authors: Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, 2900, Edouard-Montpetit Boulevard, Montreal, Quebec, H3T 1J4, Canada. Electronic address: yves.comeau@polymtl.ca.
authors: Yves
authors: Y
authors: Comeau
mesh_terms: D018441:Biofilms; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D014865:Waste Disposal, Fluid; D062065:Wastewater
chemical_list: D062065:Wastewater
keywords: Enhanced flotation; Green coagulant; Green polymer; High-rate process; Innovative separation process; Moving bed biofilm reactor