Department of Civil Engineering, Indian Institute of Technology Madras, 600036, India.
Department of Civil Engineering, Indian Institute of Technology Madras, 600036, India.
J Environ Manage. 2021 May 15;286:112202. doi: 10.1016/j.jenvman.2021.112202. Epub 2021 Feb 19.
The degradation of four recalcitrant and toxic VOCs (volatile organic compounds) present in pharmaceutical wastewater was studied using a continuous flow plasma reactor, along with evaluating its potential for real effluent treatment. The wastewater was sprayed into the plasma zone of the reactor, and it was re-circulated for better performance. The effect of different HRTs (hydraulic retention time) and initial concentrations of VOCs on the degradation efficiency were evaluated. In continuous reactor, complete removal of 200 mg/L of chloroform, chlorobenzene, and toluene was achieved at a HRT of 33.3 min, with an energy consumption of 22.4 kWh/m. The study on the effect of different inlet loading rates of VOCs on elimination capacity showed that, the removal was limited initially by diffusion of reactive species and at higher loads, it was limited by insufficient amount of reactive species produced. During degradation of VOC mixture, more than 90% removal of chloroform, chlorobenzene and toluene was achieved at HRT of 33.3 min, and the TOC removal was 78.3%. The degradation efficiency of VOC mixture reduced slightly compared to that of individual compounds, due to insufficient amount of reactive species produced. The COD and BOD removal achieved after 140 min of direct plasma treatment of real pharmaceutical wastewater in batch reactor was 92.7% and 95.2%, respectively. Coagulation pre-treatment did not have a significant effect on the plasma treatment of real wastewater. When pharmaceutical effluent treatment was carried out in continuous flow reactor, 91.8% COD removal, 90.9% BOD removal and more than 90% degradation of all VOCs were achieved at a HRT of 150 min. Plasma treatment alone was capable of effectively treating the real pharmaceutical wastewater without any pre-treatment.
采用连续流动等离子体反应器研究了四种难降解和有毒挥发性有机化合物（VOCs）在制药废水中的降解情况，并评估了其实际处理废水的潜力。将废水喷雾到反应器的等离子体区，并进行再循环以提高性能。评估了不同水力停留时间（HRT）和 VOCs 初始浓度对降解效率的影响。在连续反应器中，在 HRT 为 33.3 分钟时，完全去除 200mg/L 的氯仿、氯苯和甲苯，能耗为 22.4kWh/m。研究了不同 VOC 入口负荷率对去除能力的影响，结果表明，最初的去除受到反应性物质扩散的限制，而在较高负荷下，去除受到产生的反应性物质不足的限制。在 VOC 混合物降解过程中，在 HRT 为 33.3 分钟时，氯仿、氯苯和甲苯的去除率超过 90%，TOC 去除率为 78.3%。由于产生的反应性物质不足，与单一化合物相比，VOC 混合物的降解效率略有降低。在批式反应器中直接进行等离子体处理 140 分钟后，实际制药废水中的 COD 和 BOD 去除率分别达到 92.7%和 95.2%。混凝预处理对实际废水的等离子体处理没有显著影响。当在连续流动反应器中进行制药废水处理时，在 HRT 为 150 分钟时，COD 去除率达到 91.8%，BOD 去除率达到 90.9%，所有 VOCs 的降解率均超过 90%。等离子体处理本身能够有效地处理实际制药废水，无需任何预处理。
