Enhanced nitrogen removal in the treatment of rural domestic sewage using vertical-flow multi-soil-layering systems: Experimental and modeling insights

• Published in: Journal of environmental management 2019-06, Vol.240, p.273-284
• Main Authors: Hong, Yongyuan, Huang, Guohe, An, Chunjiang, Song, Pei, Xin, Xiaying, Chen, Xiujuan, Zhang, Peng, Zhao, Yanyun, Zheng, Rubing
• Format: Article
• Language: English
• Subjects: Factorial design; MSL system; Nitrogen removal; Rural domestic sewage; Stepwise cluster analysis; Treatment modeling
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2019.03.097

Domestic sewage in rural areas is often poorly treated and discharged into waters, resulting in negative impacts on regional environment, natural resources and human health. A cost-efficient decentralized sewage treatment technology is sustainably necessary for rural areas. In this study, a modified multi-soil-layering (MSL) system was developed to specifically treat low C/N ratio domestic sewage in rural areas. The results proved the good performance of MSLs in sewage treatment under complex conditions. The highest degradation rates of COD, TP, NH4+-N, NO3−-N, TN among all the devices could reach 98.29%, 100%, 76.60%, 96.15% and 69.86%, respectively. During the operation, MSL5 and MSL6 showed the best overall performance of contaminant removal. The effects of single factors and their interactions on the performance of MSL systems were further revealed through factorial analyses. In order to simulate and predict nitrogen removal of MSL system, a statistical relationship between TN removal rate and operation parameters was also successfully developed based on stepwise cluster analysis. Such modeling of nitrogen removal model can help develop an optimal strategy for the operation of MSL in treating low C/N ratio sewage from rural areas. [Display omitted] •Conducted low C/N ratio sewage treatment using multi-soil-layering (MSL) systems.•Explored the effects of single factors on the performances of modified MSL systems.•Analyzed the complex interactions of treatment process based on factorial analysis.•Developed a stepwise-cluster model for simulating nitrogen removal in MSL system.•Provided a sound strategy for optimal operation of MSL systems in rural areas.