考察了冬季潜流人工湿地污染河水处理系统在不同水力负荷下对污染物去除的效果。结果表明，水温15℃左右时，水力负荷由30cm/d降低到15cm/d后，氨氮转化率由14%上升到39%，COD的平均去除率由20%上升到31%，水温的降低对氨氮去除效果有很大的影响。在湿地表面覆盖塑料地膜能有效地提高系统对污染物的去除效果，覆盖地膜后，氨氮平均去除率由29.4%上升到67.6%，COD的平均去除率由29.0%提高到46.6%，脲酶活性由0.025 mg/（g•d）上升到0.037 mg/（g•d），脱氢酶的活性由0.17taL/（d•g）上升到4.54μL/（d•g）。微生物活性研究表明，覆盖地膜后系统温度的升高能提高系统中微生物的活性。植物污染物质释放试验表明，冬季地表植物腐烂会向水中释放大量的污染物质，影响系统的净化效果，因此秋季应对湿地植物及时进行收割。

中国北方地区城市纳污河道内的污染河水具有水量、水质、水温季节性变化大的特点，这给人工湿地污染河水处理系统的持续性运行造成很大困难。通过1a多的连续性运行，对潜流人工湿地污染河水处理系统的可持续运行问题进行了系统研究，年平均水力负荷为15cm/d。结果表明，季节变化对氨氮的去除效果影响很大，夏季氨氮去除效果良好，去除率达70%以上，而冬季水温降低到15V以下时，氨氮去除率降低到30%以下，但季节变化对COD去除效果的影响较小。人工湿地在夏季雨季时期可以承受较大的短期洪水水力冲击负荷，在100cm/d的负荷下，对氨氮和COD的去除率分别可以达到52%和36%。基质脱氢酶活性与温度和污染物去除效果的季节性变化存在一定的正相关关系。

Activated carbon was prepared from cattail by H3PO4 activation. The effects influencing the surface area of the resulting activated carbon followed the sequence of activated temperature > activated time > impregnation ratio > impregnation time. The optimum condition was found at an impregnation ratio of 2.5, an impregnation time of 9 hr, an activated temperature of 500°C, and an activated time of 80 min. The Brunauer-Emmett-Teller surface area and average pore size of the activated carbon were 1279 m2/g and 5.585 nm, respectively. A heterogeneous structure in terms of both size and shape was highly developed and widely distributed on the carbon surface. Some groups containing oxygen and phosphorus were formed, and the carboxyl group was the major oxygen-containing functional group. An isotherm equilibrium study was carried out to investigate the adsorption capacity of the activated carbon. The data fit the Langmuir isotherm equation, with maximum monolayer adsorption capacities of 192.30 mg/g for Neutral Red and 196.08 mg/g for Malachite Green. Dye-exhausted carbon could be regenerated effectively by thermal treatment. The results indicated that cattail-derived activated carbon was a promising adsorbent for the removal of cationic dyes from aqueous solutions.

A pilot subsurface wastewater infiltration system filled with a mixed soil of red clay + 25% cinder was constructed in a village located in Dianchi valley in south west China to treat rural sewage. At first, the system was continuously fed with rural sewage at a hydraulic loading of 2 cm d-1 for over 4 months. The removal of COD, T-P, NH4 +-N, and T-N over the operation period was achieved at average rates of 82.7, 98.0, 70.0, and 77.7%, respectively. Compared to T-P removal, the lower nitrogen removal rates were attributed to reductive soil condition in the system, which was unfavorable for the nitrification process. An intermittent operation was adopted to improve nitrogen removal. The same performances of COD and T-P removal were achieved in the intermittent operation mode. NH4 +-N removal was increased from 70% in the continuous feeding mode to over 90%, and T-N removal rate was elevated over 80% even with the average hydraulic loading as high as 8 cm d-1. Nitrogen balance calculation suggested that nitrification–denitrification was the main mechanism of nitrogen removal that eliminated 57–76% of the fed T-N. Soil redox potential measurement showed that the oxidative environment was increased through intermittent operation, encouraging nitrification. Correspondingly, soil nitrification potential was increased from less than 0.8 mg-N kg-1 h-1 in the continuous feeding mode to about 1.6 mg-N kg-1 h-1 in the intermittent operation mode.

Constructed wetlands (CWs) are considered to be important sources of nitrous oxide (N2O). In order to investigate the effect of influent COD/N ratio on N2O emission and control excess emission from nitrogen removal, free water surface microcosm wetlands were used and fed with different influent. In addition, the transformation of nitrogen was examined for better understanding of the mechanism of N2O production under different operating COD/N ratios. It was found that N2O emission and the performance of microcosm wetlands were significantly affected by COD/N ratio of wastewater influent. Strong relationships exist between N2O production rate and nitrite (r=0.421, p<0.01). During denitrification process, DO concentration crucially influences N2O production rate. An optimal influent COD/N ratio was obtained by adjusting external carbon sources for most effective N2O emission control and best performance of the CWs in nitrogen removal from wastewater. It is concluded that under the operating condition of COD/N ratio=5, total N2O emission is minimum and the microcosm wetland is most effective in wastewater nitrogen removal.