title: Treatment of nitrate-rich water in a baffled membrane bioreactor (BMBR) employing waste derived materials.
abstract: Nitrate removal in submerged membrane bioreactors (MBRs) is limited as intensive aeration (for maintaining adequate dissolved oxygen levels and for membrane scouring) deters the formation of anoxic zones essential for biological denitrification. The present study employs baffled membrane bioreactor (BMBR) to overcome this constraint. Treatment of nitrate rich water (synthetic and real groundwater) was investigated. Sludge separation was achieved using ceramic membrane filters prepared from waste sugarcane bagasse ash. A complex external carbon source (leachate from anaerobic digestion of food waste) was used to maintain an appropriate C/N ratio. Over 90% COD and 95% NO3-N reduction was obtained. The bagasse ash filters produced a clear permeate, free of suspended solids. Sludge aggregates were observed in the reactor and were linked to the high extracellular polymeric substances (EPS) content. Lower sludge volume index (40 mL/g compared to 150 mL/g for seed sludge), higher settling velocity (47 m/h compared to 10 m/h for seed sludge) and sludge aggregates (0.7 mm aggregates compared to <0.2 mm for seed sludge) was observed. The results demonstrate the potential of waste-derived materials viz. food waste leachate and bagasse ash filters in water treatment.
authors.affiliation: The Energy and Resources Institute (TERI), Darbari Seth Block, IHC Complex, Lodhi Road, New Delhi 110003, India. Electronic address: sbasu@teri.res.in.
authors.forename: Subhankar
authors.initials: S
authors.lastname: Basu
authors.affiliation: The Energy and Resources Institute (TERI), Darbari Seth Block, IHC Complex, Lodhi Road, New Delhi 110003, India.
authors.forename: Saurabh K
authors.initials: SK
authors.lastname: Singh
authors.affiliation: The Energy and Resources Institute (TERI), Darbari Seth Block, IHC Complex, Lodhi Road, New Delhi 110003, India.
authors.forename: Prahlad K
authors.initials: PK
authors.lastname: Tewari
authors.affiliation: The Energy and Resources Institute (TERI), Darbari Seth Block, IHC Complex, Lodhi Road, New Delhi 110003, India.
authors.forename: Vidya S
authors.initials: VS
authors.lastname: Batra
authors.affiliation: The Energy and Resources Institute (TERI), Darbari Seth Block, IHC Complex, Lodhi Road, New Delhi 110003, India.
authors.forename: Malini
authors.initials: M
authors.lastname: Balakrishnan
mesh_terms: D019149:Bioreactors; D006801:Humans; D008567:Membranes, Artificial; D009566:Nitrates / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods
chemical_list: D008567:Membranes, Artificial; D009566:Nitrates; D012722:Sewage
keywords: Baffled membrane bioreactor (BMBR); Food waste leachate; Nitrate removal; Sugarcane bagasse ash filters