Status assessment and solutions to improve the efficiency of the aerobic process in seafood wastewater treatment: Case study in Da Nang fisheries service industrial park

Abstract

This research presents the current status and solutions to improve the efficiency of the aerobic process in seafood wastewater treatment in the Da Nang fisheries service industrial park. The assessment included: (1) After pre-treatment, wastewater from seafood processing plants has a high concentration of organic matter and nutrients. The concentration of nutrients by N-NH4 + in the influence of biological reactors fluctuates over a large range from 106.5-475.3mg/l with a low ratio of BOD5/N-NH4 + (1.85-5.17). The ratio of C/N in the influence of the aerobic reactors is lower than 5, which causes the process’s instability. Therefore, it is fairly difficult to maintain the quality of treated water to meet discharge standards. (2) The environmental conditions of the aerobic process in biological reactors are not guaranteed. The concentration of operational activated sludge is 2-3 times higher than the recommended value. The aerobic process is operated with a low organic loading rate of 0.049-0.152gBOD5/gMLVSS.day; 0.073-0.183gCOD/g MLVSS.day; (3) In order to reach organic matter and nutrient values that satisfy column B-QCVN 11-MT:2015/BTNM, some suggestions are: (i) Adjusting the operating MLVSS concentration of 2.5-3.5g/l combined with ensuring environmental conditions of aerobic process in biological reactors; (ii) Operating parameters: HRT ≥ 8h; F/M: 0.25-0.35gCOD/gMLVSS.day (or 0.86-1.04gCOD/m3.day).