title: High-rate sulfate reduction at high salinity (up to 90 mS.cm(-1)) in mesophilic UASB reactors.
abstract: Sulfate reduction in salt-rich wastewaters using unadapted granular sludge was investigated in 0.9 L UASB reactors (pH 7.0 +/- 0.2; hydraulic retention time from 8-14 h) fed with acetate, propionate, or ethanol at organic loading rates up to 10 gCOD x L(-1) x day(-1) and in excess sulfate (COD/SO(4) (2-) of 0.5). High-rate sulfate reduction rates (up to 3.7 gSO(4) (2-) x L(-1).day(-1)) were achieved at salinities exceeding 50 gNaCl.L(-1) and 1 gMgCl(2) x L(-1). Sulfate reduction proceeded at a salinity of up to 70 gNaCl x L(-1) and 1 gMgCl(2) x L(-1) (corresponding to a conductivity of about 85-90 mS x cm(-1)), although at lower rates compared to a conductivity of 60-70 mS x cm(-1). Ethanol as well as propionate were suitable substrates for sulfate reduction, with acetate and sulfide as the end products. The successful high-rate treatment was due to the proliferation of a halotolerant incomplete oxidizing SRB population present in the unadapted inoculum sludge. Bioaugmentation of this sludge with the acetate oxidizing halotolerant SRB Desulfobacter halotolerans was unsuccessful, as the strain washed out from the UASB reactor without colonizing the UASB granules.
authors.affiliation: Sub-department of Environmental Technology, Wageningen University, "Biotechnion" - Bomenweg 2, PO Box 8129, 6700 EV Wageningen, The Netherlands.
authors.forename: Marcus V G
authors.initials: MV
authors.lastname: Vallero
authors.forename: Jan
authors.initials: J
authors.lastname: Sipma
authors.forename: Gatze
authors.initials: G
authors.lastname: Lettinga
authors.forename: Piet N L
authors.initials: PN
authors.lastname: Lens
mesh_terms: D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology*; D005232:Fatty Acids, Volatile / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D010865:Pilot Projects; D020560:Proteobacteria / Q000187:drug effects* / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*; D012965:Sodium Chloride / Q000494:pharmacology*; D013431:Sulfates / Q000378:metabolism*; D018508:Water Purification / Q000379:methods*
chemical_list: D005232:Fatty Acids, Volatile; D012722:Sewage; D013431:Sulfates; D012965:Sodium Chloride