Nitrogen removal of wastewater containing high-strength ammonium by the constructed wetlands (CWs) has been paid much attention. In this study, the ability of a partially saturated CW to treat anaerobically-digested decentralized swine wastewater under varying operating parameters from summer to winter was investigated. The partially saturated CW achieved better NH4^+-N and TN removal by tidal flow than intermittent flow. With surface loading rates of 0.108, 0.027, and 0.029 kg/(m^2·d) for COD, NH4^+-N, and TN, the partially saturated CW by tidal operation achieved corresponding removal efficiencies of 85.94%, 61.20%, and 57.41%, respectively, even at 10℃. When the rapid-adsorption of NH4^+-N and the bioregeneration of zeolites reached dynamically stable, the simultaneous nitrification and denitrification in the aerobic zeolite layer was observed and accounted for 58.82% of the total denitrification of CW. The results of Illumina high-throughput sequencing also indicated that nitnfiers (Nitrospira and Rhizomicrobiurri) and denitrifiers (Rhodanobacter and Thauera) simultaneously existed in the zeolite layer. The dominant existence of versatile organic degraders and nitrifiers/denitrifiers in the zeolite layer was related to the removal of most COD and nitrogen in this zone. The contribution of the possible nitrogen removal pathways in the CW was as follows: nitrification-denitrification (86.55%)>substrate adsorption (11.70%)>plant uptake (1.15%)>microbial assimilation (0.60%).
Zhenfeng HanYing MiaoJing DongZhiqiang ShenYuexi ZhouShan LiuChunping Yang
以构建的三级生物沸石人工湿地处理分散养猪冲洗水厌氧出水,考察了湿地的运行性能、污染物随时间变化以及生物沸石层ORP分布情况.结果表明,三级生物沸石人工湿地可高效地去除分散养猪冲洗水厌氧出水的COD、N和P,且耐NH_4^+-N冲击负荷.湿地水力负荷为0.047 m^3·(m^2·d)^(-1)时,COD、NH_4^+-N和TN(平均质量浓度分别为477.7、155.3和176.4mg·L^(-1))主要在湿地一区被去除,平均去除率分别为80.6%、55.3%和58.1%.生物沸石强化硝化作用明显,硝化产物主要为硝酸盐,湿地一区、二区和三区的NO_3^--N产生质量浓度分别为85.85、91.06和82.41 mg·L^(-1),一区沸石层产生的硝酸盐可被其下部砖渣层微生物利用水中剩余有机物为底物,通过反硝化途径去除.TP主要靠砖渣吸附去除,微生物的作用相对较小.三级湿地沸石层复氧效果均较好,大部分ORP值都保持在400 m V以上.
