WASTEWATER MANAGEMENT AND ENERGY RECOVERY IN TREATMENT OF PURIFIED TEREPHTHALIC ACID (PTA) EFFLUENT

摘要

Wastewater management and energy recovery in treatment of Purified Terephthalic Acid (PTA) effluent using anaerobic and aerobic processes is presented. Activated sludge process (ASP - two stage and single stage) and upflow anaerobic fixed film fixed bed reactor (AFFFBR) were used, individually and in combination. Studies with ASP revealed that the treatment of PTA effluent using two-stage ASP alone does not meet treated effluent quality within the prescribed Indian Standards. However, pretreatment of PTA effluent using upflow AFFFBR ensured substantial reduction in BOD (63%) and COD (62%) with recovery of biogas @1.8 - 1.96 l per l effluent treated at volumetric loading rate (VLR) of 4 - 5 kg COD/m{sup}3.d. Methane content in biogas varied between 55 and 60%. The pretreated effluent from upflow AFFFBR was then treated through single stage ASP. The biomass produced in ASP, after anaerobic treatment had very good settlability (SVI: 75 -90 ml/g) as compared to two stage ASP and the treated effluent quality with respect to BOD, COD and SS was within the prescribed Indian Standards. The alternative treatment process comprising AFFFBR and single stage ASP ensured net energy saving of 257 kW and in addition generated 442 kW energy, through AFFFBR.