Design of an Enhanced SAT Using Zeolite for the Removal of Ammonia Nitrogen at a Bengbu Aquatic Farm in China

Abstract

As one of the artificial recharge technologies, the soil–aquifer treatment (SAT) system is used for the removal of nitrogen pollution from aquaculture wastewater. An adsorption-enhanced SAT system was designed to reduce the level of nitrogen pollution below the threshold stipulated by the standards. Adsorption kinetics experiments were used to measure the adsorption capacity of zeolite and activated carbon for ammonia nitrogen. Both adsorbents can be well described by the Lagergren pseudo-second-order model, and the adsorption rates of zeolite and activated carbon for ammonia nitrogen were 72.16% and 31.40%, respectively. Combining the experimental data and the actual situation, the medium-packing method was determined and the influence of wastewater characteristics and hydrodynamic conditions on the adsorption and retention capacity of the SAT system were considered. Finally, the feasibility of the adsorption-enhanced SAT site design scheme was verified by Hydrus-1D model simulation. The study found that the design scheme for the situation in the study area was feasible; however, the surrounding underground environment still had a risk of pollution during the operation of the site. Therefore, further research is needed for the nitrogen pollution to be completely removed within the scope of the SAT site.