Anaerobic treatment of effluents from an industrial polymers synthesis plant

The feasibility of the anaerobic treatment of an industrial polymer synthes is plant effluent was evaluated. The composition of the wastewater includes acrylates, styrene, detergents, a minor amount of silicates and a signific ant amount of ferric chloride. The average chemical oxygen demand (COD) cor responding is about 2000 mg/l. The anaerobic biodegradability of the efflue nt is shown and the toxicity effect on the populations of anaerobic bacteri a is evaluated. The results of the anaerobic biodegradation assays show tha t 62% of the wastewater compounds, measured as GOD, could be consumed. An u pflow anaerobic sludge blanket (UASB) reactor was used in the evaluation, i t has a diameter-height ratio of 1:7, and 4-liter volume. The inoculum was obtained from a UASB pilot plant that treats brewery wastewaters. At the be ginning of the operation, the biomass showed an anaerobic activity of 0.58 gCOD/(gVSSxd), it decreased only 2.5% in the subsequent 4 months. After 35 days of continuous operation, the reactor was operated at different steady states for 140 days. The COD was maintained at 2200 mg/l in the feed. The r esults were: organic loading rate (OLR): 4.3 kg COD/(m(3)xd), hydraulic ret ention time: 12 h, superficial velocity: 1 m/h, average biogas productivity : 290 L CH4/kg COD fed, biogas composition: 70-75% methane and a COD remova l percentage >75%. (C) 1999 Elsevier Science Ltd. All rights reserved.