潜流湿地处理生活污水时的强化策略

研究在潜流湿地处理生活污水时通过预处理强化、介质优化和工艺改进克服现有技术缺陷的可行性.改进方法包括化学强化预处理、预曝气、添加氮吸附介质、添加磷吸附介质、湿地高浸润线、中浸润线、低浸润线和动态浸润线运行.结果表明,化学强化预处理不仅可以除磷,而且削减湿地污染负荷可使后续湿地面积减小63%,但是不能有效脱氮.预曝气仅使氨氮去除率提高了1%.添加氮吸附介质的有效时间短,运行前3个月对NH₄⁺-N去除率为84%,5个月后下降到64%.添加磷吸附介质的有效时间较长,可维持数年.因此,脱氮过程只有通过基质微生物实现.稳态浸润线下对COD、NH₄⁺-N、TN、TP的去除率,高浸润线湿地为50%、21%、32%、-26%;中浸润线湿地为53%、48%、48%、-14%;低浸润线湿地为74%、96%、35%、22%.提出动态浸润线及序批式潜流人工湿地工艺(CBSW),其对COD、NH₄⁺-N、TN、TP去除率为67%、62%、53%、33%.CBSW实现了单级湿地内好氧/缺氧环境的交替出现,提高了脱氮能力,除污综合表现最佳.

Enhancement Strategies in Vertical Flow Constructed Wetlands for Domestic Wastewater Treatment

Because pollutants load is too high for root oxygenation,plant absorbance of nutrient and media absorption in vertical down flow wetland to remove pollutants from domestic wastewater,some deficiency do exist,which were confronted by pre-treatment enhancement,media optimization and technological revolution in this study.The strategies include chemically enhanced settlement,pre-aeration,addition of N-adsorption media and P-adsorption media,high,middle and low water level and dynamic saturation line within the soil profile.Chemically enhanced settlement can not only remove P but reduce 63% of the surface area of the connected wetland,but can not remove N effectively.Pre-aeration just increase 1% of the removal percentage of(NH₄⁺-N.) The wetland with addition of N-adsorption media has the initial removal percentage of 84%,which decreases to 64% for consumption of adsorption capacity in 5 months.The saturation time of P-adsorption media is longer for the lower load of P on wetland.So,nitrogen removal only can be achieved by microorganism.Under stable saturation line,removal percentage of COD,(NH₄⁺-N,) TN,TP in wetland with high water level is 50%, 21%,32%,26%,and those in wetland with middle water level is 53%,48%,48%,-14%,and those in wetland with low water level is 74%,96%,35%,22%.Dynamic saturation line was proposed and Cyclic Batch Subsurface Wetland(CBSW) was invented in this paper,which achieves removal percentage of 67%,62%,53%,33% individually for COD,(NH₄⁺-N,) TN,TP.The result suggest that CBSW enhances N removal ability in single-stage wetland and perform better in anti-clogging,and so is the best enhancement strategy in subsurface wetland for domestic wastewater treatment.