Treatment of swine wastewater in a biological system for disposal in a sandy soil

ABSTRACT This work aimed to evaluate the efficiency of a system composed of a UASB reactor followed by post-treatment with an aerobic granular sludge reactor (AGS) in the treatment of swine wastewater (SW) for disposal in sandy soil. The characteristics of the treated effluent and the soil from a disposal site were evaluated, as well as the parameters of mobility of contaminants such as dispersion coefficient (D), dispersivity (λ), delay factor (R), and Péclet number (Pe) were determined. Treated SW was percolated in a permanent flow regime in columns of saturated soil. Elution curves (breakthrough curves) were generated, obtaining the transport parameters by adjusting the solute transport equation in the soil. The soil used was characterized as a quartzene soil with a sandy texture. It was observed that, although the treatment presents high removal efficiencies for COD, BOD, TSS, nitrogen, and phosphorus, the treated SW still did not meet some parameters for surface water discharge or soil disposal based in current legislation. Except for phosphate and potassium, ions showed a tendency to move in the soil and to contaminate the groundwater.

摘要 本研究旨在评估由上流式厌氧污泥床反应器（UASB）辅以好氧颗粒污泥反应器（AGS）后处理工艺组成的系统，在处理猪场废水（SW）以用于沙土处置方面的效能。研究评估了处理后出水以及处置场地土壤的特性，同时测定了污染物迁移参数，包括弥散系数（D）、弥散度（λ）、延迟因子（R）与佩克莱特数（Pe）。将处理后的猪场废水以恒流工况在饱和土柱中进行渗滤，生成洗脱曲线（穿透曲线），通过拟合土壤溶质运移方程得到相关运移参数。所用土壤为砂质质地的石英质土壤。研究发现，尽管该处理工艺对化学需氧量（COD）、生化需氧量（BOD）、总悬浮固体（TSS）、氮与磷均具有较高的去除效率，但处理后的猪场废水仍未达到现行法规中地表水排放或土壤处置的部分参数要求。除磷酸盐与钾离子外，其余离子在土壤中均表现出迁移并污染地下水的趋势。