Techno-economic analysis of municipal wastewater land treatment systems in China

This paper analyses the capital costs, power consumption and operation costs of municipal wastewater land treatment systems, including rapid infiltration, slow-rate infiltration, overflow and constructed wetland, by means of series engineering design. The results show that land treatment can save 50-70% of capital costs, 80-90% of power and 75-85% of operation costs when compared with secondary treatment.

Ecological engineering land treatment systems──A new development in China

This paper elucidated the necessity and possibility of developing the technology of land treatment on the basis of the analysis of shortage and pollution status of water resources in China.The historical development of this technology in the world was briefly reviewed and the distinction between land treatment and conventional wastewater irrigation was discussed in details. The fundamental characteristics and functions as well as the integrity and compatibility of this ecological engineering were also summarized. It was finally concluded that this technology for wastewater treatment has broad prospects of application in China.

Study of prediction for groundwater contamination in wastewater land treatment system

This paper uses a prediction model of groundwater pollution based on the experiments in the laboratory and in field .The model, which was tested and calibrated by the field observated data ,satisfactorily simulated the field conditions in land treatment system of wastewater . Particularly , the model can provide the reliable pollution prediction of heavy metals , organisms and nitrogen . The model was used to predict the groundwater pollution caused by the land treatment system in the region of North China . The calibration of the model showed that correlation coefficients between the tested and predictive data of Cr6+. As3+, organism and NH4+ could reach 0.990, which proved that the model possessed the realistic instructive significance for design and use of wastewater land treatment systems .

Nitrogen Removal Efficiency of the Reclaimed Water by Land Treatment System

[Objective] The research aimed to study nitrogen removal effect of the land treatment process on reclaimed water. [Method] By using land treatment system, reclaimed water which reached one-level A standard was conducted advanced processing, and nitrogen removal efficiency of the effluent was inspected. [ Result] There was a positive correlation between organic matter content of the soil medium and nitrogen removal effect. With appropriate soil medium, TN and NH3-N could obtain the removal efficiency of more than 90% and 75% respectively, and they could be removed at 30 and 10 cm height of soil medium respectively with land treatment system to treat reclaimed water. [ Conclusion ] The research provid- ed theoretical basis for application of the land treatment system into nitrogen removal of the reclaimed water.

Technical Innovation of Land Treatment Systems for Municipal Wastewater in Northeast China

On the basis of ecological principles including holistic optimization, cycling and regeneration, and regional differentiation, land treatment systems (LTSs) for municipal wastewater were continuously explored and updated in the western Shenyang area and the Huolinhe area, China. Intensified pretreatment, addition of a man-made soil filtration layer, and use of an ecologically diversified secondary plant cover were proved to be technically feasible. Hydraulic loading was determined according to the assimilation capacity of soil ecosystems, thus ensuring safe operation of wastewater treatment. This modernized and alternative approach to wastewater treatment had been widely applied in middle-sized and small cities and towns of Northeast China, and these innovative systems in some areas had indicated favorable ecological, social, and economic benefits.

Experimental analysis of a nitrogen removal process simulation of wastewater land treatment under three different wheat planting densities

Nitrogen contaminant transport, transformation and uptake simulation experiments were conducted in green house under three different planting density of winter wheat. They were Group A, planting density of 0.0208 plants/cm 2, Group B, 0.1042 plants /cm 2, and Group C, 0.1415 plants/cm 2. The capacity and ratio of nitrogen removal were different on three kinds of conditions of wastewater land treatment. From analysis of wastewater treatment capacity, wastewater concentration and irrigation intensity for Group C were suitable and nitrogen quantity added was 2 times of that for Group B, 2.6 times for Group A while nitrogen residue was only 7.06%. Hence, wastewater irrigation and treatment design with purpose of waste water treatment should select the design with maximum capacity, optimal removal ratio and least residue in soil, which was closely related to crop planting density, crop growth status and also background nitrogen quantity in soil.

Rapid infiltration wastewater treatment for small communities in Beijing

This rapid infiltration (RI) system is proposed as the first one in China. The RI system treated 500 m3/d of municipal and industrial wastewater. About 0.36 ha of field was used. It has been evaluated that the RI system has an excellent ability to treat the wastewater. The infiltration rate was 50.3 m/a.

慢速渗滤土地处理系统对沈阳西部城市污水有机污染物净化效果的研究

本文研究了慢速渗滤土地处理系统对沈阳西部城市污水中有机污染物的净化效果和有机污染物在土地处理系统土壤中的残留情况。结果表明,在试验条件下,系统对有机污染物具有良好的净化效果,大多数有机污染物在系统输出水中未被检出,少数重点有机污染物在系统输出水中的浓度也明显降低,其中苯、氯苯、1,2-和1,4-二氯苯、苯酚,邻苯二甲酸二丁酯、γ-666等的含量已明显低于地面水水质标准建议值。系统对绝大多数重点有机污染物的去除率达95—100％,而不同重点有机污染物在土壤中的残留率为0—3％。

快速渗滤土地处理系统对城市生活污水中N、P去除的优化研究

为了探索城市生活污水中N、P去除,在实验室内采用混合土为介质,以均匀设计原理为指导,进行模拟人工快速渗滤系统对城市生活污水中N、P的去除。研究不同介质配比,淹水时间,湿干比3种因素组合对污水处理的最优运行模式。试验结果表明:通过选取混合土为介质及以上3个参数是可行的;通过回归统计得出最优模型。

西安市污水土地处理系统水力负荷的模拟分析

本研究以西安地区长期的气象资料和土壤资料为基础,利用美国农业部自然资源保护局所推荐的田间水管理模型 DRAINMOD,对不同灌溉制度和田间排水条件下,污水处理系统的水力负荷进行了模拟;并对模型输入参数的敏感性进行了分析。结果表明,地面排水情况对系统的处理能力影响不大,采取少灌、勤灌的灌溉制度,能够增加系统的污水处理量。与目前污灌情况相比较,西安地区所推荐的污水灌溉量大致与在不考虑田间排水情况下,模型计算的年处理量持平。

人工快速渗滤系统中人工快渗池对污染物的去除效果研究

为了阐明人工快速渗滤系统中人工快渗池对污染物的去除效果,对深圳市某污水处理厂的人工快渗池进、出水各项水质指标进行了全面研究。结果表明,该人工快渗池进水水质波动不大,出水水质稳定且良好,对COD和BOD5均有良好的去除效果;NH3-N去除率在97%以上,硝化作用很强,NH3-N在硝化菌的作用下几乎全部被氧化成硝态氮;SS去除率在90%以上,TP去除率在40%～70%。研究结果有助于系统地了解人工快渗池在整个人工快速渗滤系统中所发挥的作用,为提高人工快速渗滤系统的除污能力提供了理论依据。

土壤－植物系统中多环芳烃和重金属的行为研究

对土壤中多环芳烃和重金属的行为研究表明，与对照相比，０—２０ｃｍ以上表土层存在多环芳烃和重金属积累，２０ｃｍ以下土层未发现积累；与春、秋两次采样结果相比，土壤中多环芳烃的含量有所下降，表明土壤微生物对多环芳烃有一定降解作用，且其降解程度与土壤－植物系统的生态结构有关．菲在地下水中检出浓度较高，表明这一污染物有向下迁移的可能性．此外，柳树对土壤中重金属Ｃｄ的积累有明显的削减与净化作用．本研究表明，严格限制污水中多环芳烃和重金属的污染负荷以及设计合理的生态结构是避免多环芳烃和重金属在土壤中积累的关键．

城市污水土地处理专家系统研究

在进行污水土地处理适宜性调查和研究基础上，应用ＴｕｒｂｏＰｒｏｌｏｇ和Ｃ程序语言建立了污水土地处理专家系统（ＬＴＥＳ）．通过测试表明，该系统能对土地处理系统的进水水质、场地适宜性、出水目标等指标进行快速准确的判断和预测，解决了污水土地处理的选址、处理工艺类型选择等问题，是科学设置污水生态工程的重要工具．

我国农村生活污水处理及利用分析

结合我国农村水环境污染现状及农村生活污水水质、水量特点,提出适合农村生活污水处理的自然生态处理系统是农村生活污水主要的处理模式。分析了土地处理系统及稳定塘处理系统净化机理、污水处理应用现状与发展趋势以及农村生活污水处理后的利用措施。

城市污水土地处理适宜性评价系统

应用人工智能程序语言ＴｕｒｂｏＰｒｏｌｏｇ和Ｃ语言建立了污水土地处理适宜性评价系统。通过测试表明，该系统能对土地处理的进水水质、场地适宜性、出水目标进行快速准确的判断和预测，解决了污水土地处理的选址、处理工艺类型选择等问题，是科学设置污水土地处理生态工程的重要工具。

土地处理技术在干旱-半干旱过渡带生态建设中的应用

土地处理系统是在干旱 -半干旱过渡区实现污水无害化、资源化的有效技术。内蒙古霍林河矿区污水土地处理系统设计与运行结果表明 ,该区具备推广土地处理技术的良好条件 ,土地处理系统应以慢速渗滤和污水资源利用型为主 ,实现污水处理与生态环境建设的结合。污水资源的利用有助于增加镶嵌型复合生态系统的稳定性 ,加速人工林的成林郁闭 ,增加林木蓄积量 ,改善干旱。

用溶质运移理论评价污水土地处理系统长期运行的处理效果

美国农业部自然资源保护局所推荐的田间水管理模型(DRA INM OD)在模拟分析污水土地处理系统水力负荷时,只从水力角度出发,根据土壤的入渗、蒸发和排水情况来计算污水灌溉量,对污水的处理效果未加考虑。该文利用溶质运移理论对DRA INM OD模型所模拟的水力过程进行排水出流浓度计算。以西安地区为例的模拟结果表明:随着排水间距减小,水力负荷逐渐增大,处理效果明显变差;该方法还可以用来确定污水土地处理系统达到不同水质标准所要求的污水预处理程度。

土地系统处理白酒企业锅底水的实验研究

采用慢速渗滤土地处理系统对白酒企业酿酒底锅水处理效果实验研究,分析土地处理系统在不同进水量、pH值、停留时间条件下对高浓度有机废水COD的去除效果。结果表明:①随着底锅水pH值的降低,出水COD值增高,pH值大于6时去除率最高;②进水4h后随着时间的增加,出水COD值逐渐降低,可选择4h后出水作为处理后的出水;③时间、pH值、进水量3个因素对处理效果的影响从大到小为:出水时间、pH值、进水量;④土地处理系统处理高浓度有机废水能够达到排放标准。

土地处理池塘污水影响因素的实验研究

通过户外动态土柱模拟实验,研究了淹水时间、土壤厚度、土壤粒径和淹水深度对池塘污水处理效果的影响。实验结果表明:连续淹水超过4～5d,COD去除率明显下降;相同进水条件下,土层厚度在120cm处,COD去除率达到80%以上;土壤粒径<0.1mm时,COD去除率达到90%;在土层厚度120cm处,淹水深度为60cm时,COD去除率仅40%。

氧化还原环境对污水土地处理系统的影响

不断变化的氧化还原环境,使污水土地处理系统具有了对污染物特别是氮及有机物的独特净化机理及良好的处理效果。对污水土地处理系统而言,氧化还原环境是影响甚至控制污水处理效果的一个重要因素。了解不同氧化还原环境中各种污染物的存在状态、转化机理、处理效率,通过有效途径改善土壤的氧化还原环境,有助于提高系统的处理效率,加快实现污水的无害化、资源化。