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.

The adsorption of methyl orange and methyl violet from aqueous solutions by Phragmites australis activated carbon (PAAC) was studied in a batch adsorption system. The adsorption studies include both equilibrium adsorption isotherms and kinetics. Several isotherm models were investigated and the adsorption isotherm data were best represented by the Temkin isotherms. The kinetic data were well described by the pseudosecond-order kinetic model. The mechanism of the adsorption process was determined from the intraparticle diffusion model. The results indicate that PAAC could be employed as a low-cost alternative for the removal of the textile dyes from effluents.

Activated carbon was prepared from an inexpensive and renewable carbon source, Typha orientalis, by H3PO4 activation and then impregnated with different Mn salts and tested for its Neutral Red (NR) adsorption capacities. The amount of Mn impregnated in the activated carbon was influenced by the anion species. Impregnation with Mn decreased the surface area, changed the pore size and crystal structure, and introduced more acidic functional groups such as carboxyl, lactone and phenol groups. The optimum adsorption performance for all the activated carbons was obtained at pH 3.7, Mn–Carbon dose of 0.100 g/100 ml solution and contact time 4.5 h. The adsorption isotherms fit the Langmuir isotherm equation. The kinetic data followed the pseudo-second-order model. The thermodynamic parameters indicated that the processes were spontaneous and endothermic. According to these results, the prepared Mn modified activated carbons are promising adsorbents for the removal of Neutral Red from wastewater.

Low cost activated carbon was prepared from Polygonum orientale Linn by phosphoric acid activation. Its ability to remove the basic dyes, malachite green (MG) and rhodamine B (RB) was evaluated. The surface area of P. orientale Linn activated carbon (PLAC) was found to be 1398 m2/g. The effects of experimental parameters such as initial concentration, contact time, pH, ionic strength and temperature on the adsorption were investigated. Alkaline pH was more favorable for MG adsorption, whereas acidic pH was better for RB uptake. Adsorption of dyes on PLAC was weakly dependent on ionic strength. The adsorption kinetics was found to be best represented by the pseudo-second-order kinetic model. The mechanism of the adsorption process was determined from the intraparticle diffusion model. The equilibrium adsorption data was well described by the Langmuir model. Thermodynamic study showed that the adsorption was a spontaneous, endothermic process.

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。