title: Degradation of 4-chlorophenol in UASB reactor under methanogenic conditions.
abstract: Treatment of simulated wastewater containing 40 mg/l of 4-chlorophenol (4-CP) was carried out in an upflow anaerobic sludge blanket (UASB) reactor under methanogenic condition. The performance of this test UASB reactor was evaluated in terms of 4-CP removal. Hydraulic retention time (HRT) and substrate:co-substrate ratio for the 4-CP removal was optimized by varying the influent flow rate (13-34.7 ml/min) and sodium acetate concentration (2-5 g/l), respectively. A control UASB reactor, which was not exposed to 4-CP was also operated under similar conditions. Organic loading rate (OLR) was varied in the range of 2-5.3 kg/m(3)/d and 1.7-4.2 kg/m(3)/d, respectively, for HRT and substrate:co-substrate ratio studies, respectively. The optimum HRT and substrate:co-substrate ratio for the removal of 4-CP was 12h and 1:75, respectively. Removal of 4-CP achieved at optimum HRT and substrate:co-substrate ratio was 88.3+/-0.7%. Removal of 4-CP occurred through dehalogenation and caused increase in chloride ion concentration in the effluent by 0.23-0.27 mg/mg 4-CP removed. The ring cleavage test showed the ortho mode of ring cleavage of 4-CP. Change in the elemental composition of the anaerobic biomass of UASB reactors was observed during the study period. Concentration of Ca(2+) increased in the biomass and this could be attributed to the biosoftening. Specific methanogenic activity of the sludge of control and test UASB reactor was 0.832 g CH(4) COD/g VSS d and 0.694 g CH(4) COD/g VSS d, respectively.
authors.affiliation: Centre for Environmental Science and Engineering, Indian Institute of Technology, Powai, Mumbai 400 076, India.
authors.forename: Partha Sarathi
authors.initials: PS
authors.lastname: Majumder
authors.forename: S K
authors.initials: SK
authors.lastname: Gupta
mesh_terms: D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D018533:Biomass; D019149:Bioreactors; D002118:Calcium / Q000737:chemistry; D002733:Chlorophenols / Q000737:chemistry*; D007220:Industrial Waste; D008697:Methane / Q000737:chemistry; D008956:Models, Chemical; D012722:Sewage; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis; D018508:Water Purification
chemical_list: D002733:Chlorophenols; D007220:Industrial Waste; D012722:Sewage; D014874:Water Pollutants, Chemical; C029107:4-chlorophenol; D008697:Methane; D002118:Calcium