Oleochemicals industry effluence mainly contains a high chemical oxygen demand (COD) in a range of 6000–20,000 ppm. An effective biological wastewater treatment process must be carried out before wastewater is discharged into the environment. In this study, a submerged bed biofilm reactor (SBBR) was adapted to the biological oleochemical wastewater treatment plant observed in the present study. The effect of wastewater flow rate (100–300 mL/min), Cosmoball^® percentage in the SBBR system (25–75%), and percentage of activated sludge (0–50%) were investigated in terms of COD reduction. The Box-Behnken design was used for response surface methodology (RSM) and to create a set of 18 experimental runs, which was needed for optimising the biological oleochemical wastewater treatment. A quadratic polynomial model with estimated coefficients was developed to describe COD reduction patterns. The analysis of variance (ANOVA) shows that the wastewater flow rate was the most effective factor in reducing COD, followed by activated sludge percentage and Cosmoball^® carrier percentage. Under the optimum conditions (i.e., a wastewater flow rate of 103.25 mL/min a Cosmoball^® carrier percentage of 71.94%, and an activated sludge percentage of 40.50%) a COD reduction of 98% was achieved. Thus, under optimum conditions, as suggested by the BBD, SBBR systems can be used as a viable means of biological wastewater treatment in the oleochemicals industry.

油脂化学工业废水主要包含6000-20,000 ppm范围内的高化学需氧量（COD）。在废水排入环境之前，必须进行有效的生物废水处理过程。在这项研究中，将淹没床生物膜反应器（SBBR）应用于本研究中观察到的生物油脂化学废水处理厂。废水流量的（100-300毫升/分钟）的效果，Cosmoball ^®以减少COD的方式研究了SBBR系统中的百分比（25％至75％）和活性污泥的百分比（0％至50％）。Box-Behnken设计用于响应面方法（RSM），并创建了一组18个实验运行，这是优化生物油脂化学废水处理所必需的。建立具有估计系数的二次多项式模型来描述COD减少模式。的方差分析（ANOVA）示出了分析，该废水流率为降低COD的最有效的因素，其次是活性污泥百分比和Cosmoball ^®载体百分比。在最佳条件下（即，103.25毫升/分钟的Cosmoball废水流量^®载体百分比为71.94％，活性污泥百分比为40.50％），COD降低了98％。因此，在最佳条件下，如BBD所建议，SBBR系统可用作油脂化学工业中生物废水处理的可行方法。