Department of Civil Engineering, Sardar Vallabhbhai National Institute of Technology, Surat 395007, India E-mail:
Department of Civil Engineering, Sardar Vallabhbhai National Institute of Technology, Surat 395007, India.
Water Sci Technol. 2024 May;89(10):2625-2645. doi: 10.2166/wst.2024.155. Epub 2024 May 15.
In this study, the performance of four different pre-treatment alternatives for granular media filtration, namely, settling, aeration, coarse media filtration and chemical coagulation were compared experimentally. Further, analytical hierarchy process (AHP) was used to compare their performance based on economic, environmental, technical and performance criteria. Performance of settling and aeration were evaluated up to 24 h duration. The coarse media filter was intermittently operated with 10 L of greywater in downflow mode while alum was used for chemical coagulation. Experimental results showed that settling up to 6 h did not show significant removal of different pollutants whereas 24 h settling resulted in moderate removal of turbidity and organic content but was not efficient in the removal of nutrients and faecal coliforms. Chemical coagulation reduced 93, 66, 48 and 97% of turbidity, COD, NH-N and faecal coliforms, respectively from greywater but resulted in excessive sludge generation and is difficult to adopt on-site and requires skilled supervision. Coarse filtration of greywater resulted in 61, 41, 36 and 35% removal of turbidity, COD, PO-P and faecal coliforms, respectively. Considering different criteria AHP gave coarse filtration as the best pre-treatment option to the granular media filters treating greywater.
在这项研究中，我们比较了四种不同的预处理方法（沉淀、曝气、粗粒介质过滤和化学混凝）在颗粒介质过滤中的性能。此外，我们还使用层次分析法（AHP）根据经济、环境、技术和性能标准来比较它们的性能。沉淀和曝气的性能评估持续了 24 小时。粗粒介质过滤器以 10L 的灰水为处理对象，采用下向流模式间歇运行，而使用硫酸铝进行化学混凝。实验结果表明，沉淀 6 小时内对不同污染物的去除效果不明显，而沉淀 24 小时可适度去除浊度和有机物，但对营养物质和粪大肠菌群的去除效果不佳。化学混凝可将灰水中的浊度、COD、NH-N 和粪大肠菌群分别降低 93%、66%、48%和 97%，但会产生过多的污泥，难以现场采用，且需要熟练的监督。灰水的粗粒过滤可分别去除浊度、COD、PO-P 和粪大肠菌群的 61%、41%、36%和 35%。考虑到不同的标准，AHP 认为粗粒过滤是处理灰水的颗粒介质过滤器的最佳预处理方法。
