Water reuse potential in truck wash using a Rotating Biological Contactor

This study evaluated the water reuse potential for truck washing using the effluent treated by a Rotating Biological Contactor (RBC) operated in full scale. In order to evaluate the reuse potential, a mass balance was performed for the reuse system taking into account the concentration of Total Dissolved Solids as the critical contaminant. The treatment system produced an effluent with average concentration of color, turbidity, TDS and BOD5 of 45 ± 14 uC, 15 ± 6.0 NTU, 244 ± 99 mg TDS / L and 14 ± 7.3 mg O2 / L, respectively. Based on the mass balance, and considering the TDS concentration established in NBR 13.696, if the final rinse does not use clean water, the potential for effluent reuse can reach 40%. However, if clean water is used as 30% of the total rinsing volume, it would be possible to reuse 70% of the treated effluent without compromising truck washing performance. This water reuse approach would result in an operational cost reduction of R$ 2,590.75/month.

本研究针对全规模运行的旋转生物接触器（Rotating Biological Contactor，RBC）处理后的出水，评估了其用于卡车清洗的水回用潜力。为准确评估该回用潜力，本研究针对该回用系统开展物料衡算，以总溶解固体（Total Dissolved Solids，TDS）浓度作为关键污染物指标纳入考量。该处理系统产出的出水，其色度、浊度、总溶解固体及五日生化需氧量（Biochemical Oxygen Demand, BOD5）的平均浓度分别为45±14 uC、15±6.0 NTU、244±99 mg TDS·L⁻¹及14±7.3 mg O₂·L⁻¹。基于上述物料衡算结果，并结合NBR 13.696标准中规定的总溶解固体浓度限值，若最终冲洗环节不使用清水，则该出水的回用潜力可达40%；但若总冲洗用水量中有30%采用清水，则可在不影响卡车清洗效果的前提下，回用70%的处理出水。该水回用方案可实现每月2590.75巴西雷亚尔（R$）的运营成本削减。