Biofloc production in activated sludge system treating shrimp farming effluent

ABSTRACT The release of wastewater and the shrimp feed cost are the main challenges faced by the shrimp farming industry. An alternative solution to both problems is biofloc production in a unit external to the farm, in an activated sludge system for effluent treatment. The treatment system’s influent was composed of the shrimp farm wastewater supplemented with urea and sugarcane molasses. The results show that the average removal of chemical oxygen demand was 71% and the average biofloc production in the reactor was approximately 1.5g.L-1. Adding molasses to the influent contributed to the increase in the quantity and diversity of existing microorganisms that are beneficial to cultured shrimp. The mass balance of nitrogen compounds confirmed that nitrification occurred in the system. Therefore, the use of the activated sludge system is a viable and environmentally suitable alternative to produce bioflocs and shrimp farming effluent treatment.摘要 虾类养殖业当前面临的两大核心挑战为养殖废水排放管控与虾饲料成本高企。针对这两类难题的协同解决方案之一，是在养殖场外部独立单元内的活性污泥系统（activated sludge system）中开展生物絮团（biofloc）生产，同步完成养殖废水处理。本研究的处理系统进水由虾场养殖废水辅以尿素与甘蔗糖蜜配制得到。结果表明，系统对化学需氧量（Chemical Oxygen Demand, COD）的平均去除率达71%，反应器内生物絮团的平均产量约为1.5g·L⁻¹。向进水中添加糖蜜可显著提升对养殖对虾有益的微生物的种群数量与多样性水平。氮化合物质量平衡分析证实，该系统内发生了硝化作用。综上，采用活性污泥系统生产生物絮团并处理虾类养殖废水，是兼具可行性与环境适宜性的替代技术方案。