Effect of long-term operation of a subsurface wastewater infiltration system (SWIS) based on the limiting value of environmental carrying capacity

• Published in: Ecological engineering Vol. 92; pp. 190 - 198
• Main Authors: Zheng, Peng, Cui, Jianyu, Hu, Lin, Chen, Peizhen, Huang, Jiewen, Cheng, Shanping, Mu, Kangguo
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2016
• Subjects: Domestic sewage; Environmental carrying capacity; Nitrate; Subsurface wastewater infiltration system; Subsurface wastewater infiltration system; Environmental carrying capacity; Nitrate; Domestic sewage
• ISSN: 0925-8574; 1872-6992
• DOI: 10.1016/j.ecoleng.2016.03.024

To evaluate the environmental carrying capacity of a subsurface wastewater infiltration system (SWIS) and the removal effect of nitrogen, the simulated soil column experiments were performed. After the SWIS was operated for three years with a hydraulic loading of 5mmd−1, the results indicated that the total nitrogen (TN) removal rate and the ammonia nitrogen (NH4±-N) removal rate were 74.22%, 99.69%, respectively, for the high pollution load treatment system and 80.45%, 99.72%, respectively, for the low pollution load treatment system (TN concentrations of 80mgL−1 and 40mgL−1for the two treatment systems, respectively). The ratios of the nitrate nitrogen (NO3−-N) concentration in the effluent, which satisfied grade III of the Chinese groundwater standard and the maximum international contaminant level of drinking water were 13.33%, 0.00% and 87.87%, 37.43%, respectively. Adopting the 20mgL−1 of the NO3−-N concentration in the soil leachate as the evaluation criterion, the environmental carrying capacity of nitrogen in the SWIS was in a range of 600kgNha−1y−1 to 1200kgNha−1y−1.