Biotreatment of simulated atrazine wastewater using hybrid upflow anaerobic sludge blanket (HUASB) reactor

In the present investigation, an attempt was made to develop a treatment system for the simulated atrazine wastewater using a hybrid upflow anaerobic sludge blanket (HUASB) reactor. The reactor was operated for 90 days in three phases. In phase-I (0-25 days), acclimatization was done with the acclimatization media. In phase-II, (26-72 days), the experiment was carried out to find out the effect of atrazine and sucrose concentration 24 h HRT. Maximum atrazine reduction was observed when influent sucrose concentration was 300 mg/l and atrazine concentration of 5mg/l, among the various combinations of influent sucrose and atrazine. The gas production rate increased with increase of the sucrose concentration from 300 mg/l to 1000 mg/l. Maximum biogas production rate of 473 ml/d was recorded when the atrazine and sucrose influent concentrations were maintained at 25 mg/l and 1000 mg/l respectively. In phase-III, for 12 h HRT, the steady state COD removal efficiency and atrazine degradation efficiency were 70% and 59% respectively, for the wastewater containing 5 mg/l of atrazine and 300 mg/l of sucrose. From the SEM observation of sludge granules, two species of methanogens, namely, Methanosarcina spp., and Methanobacterium spp. were identified.