ALTERNATING ANOXIC-AEROBIC PROCESS FOR TREATMENT OF LOW-SALINITY SHRIMP AQUACULTURE WASTEWATER

Abstract

This paper researched applying an alternate aerobic - anoxic system for low-salinity shrimp aquaculture wastewater treatment in Vietnam. The study evaluated the effect of salinity on the performance of the wastewater treatment system. Next, the influence of intermittent aeration mode (IA) and water retention time (HRT) on the treatment efficiency of the system was also investigated. The results showed that the treatment efficiency of the system was significantly affected when the salinity was at 1.5%. COD and ammonium removal efficiency decreased from 93.85 and 98.7% (0% salinity) down to 45.54; 72.24% (1.5% salinity). Besides, the increase in salinity improved the settling capacity of the activated sludge. The SVI decreased from 90 ml/g (0% salinity) to 38 ml/g (1.5% salinity). For different IA modes, the treatment efficiency was different. In which, the aeration/non-aeration mode with 60:60 minutes achieved the highest efficiency in ammonium and COD removal, reaching 99.81% and 97%, respectively. The optimal HRT value selected for the treatment was 12 hours.