This study was aimed to biologically treat domestic wastewater using identified bacterial consortium for chemical pollutants removal by treating/passing it through sand biofilters. The identification, toxicity test, and the optimum dose of the investigated bacterial consortium were carried out using Microtox analyzer and Batch biological treatment, respectively. Furthermore, application of sedimentation followed by gravel and sand biofilters for wastewater treatment was evaluated. The results showed that the bacterial consortium is composed of Pediococcus acidilactici, Pediococcus pentosaceus, Lactobacillus plantarum, and Bacillus subtilis. The optimum dose for wastewater treatment within 6 h of contact time is 2.5 mg/L, this dose (2.5 mg/L) has no toxic effect. The removal percentage of chemical oxygen demand (COD), biological oxygen demand (BOD), total solids (TS), total dissolved solids (TDS), total suspended solids (TSS), ammonia, nitrate, total Kjeldahl nitrogen (TKN), and oil and grease reached 93.4, 83.5, 37.5, 49.2, 93.4, 100, 55.7, 76.6, and 76% in the effluent of the treated wastewater, respectively after the third sand biofilter filtration. It can be concluded that using bacterial consortium for domestic wastewater treatment could be a good tool for chemical pollutants removal. Moreover, this study provides low cost and eco-friendly tool for domestic wastewater treatment using simple multistage biofilters based on an identified bacterial consortium. This system can be upscaled for the treatment of larger volumes of wastewater.
Keywords: BOD; Bacterial consortium; Biological treatment; COD; Chemical pollutants; Quick sand filter.