地下渗滤污水处理系统中基质的研究进展

地下渗滤污水处理系统是污水土地处理系统之一,可以同时实现污水就地处理与回用,受到了世界各国科学家的越来越广泛的重视。作为该系统的核心单元,基质成为研究热点之一。文中介绍了地下渗滤污水处理系统中基质的构成和作用,分析了影响系统性能的基质因素,提出了基质的选择原则,总结了目前的各种研究成果,并对今后的研究方向进行了展望,旨在为地下渗滤污水处理技术的理论研究和实践应用提供一定的借鉴意义。     

耕作措施对土壤入渗产流影响的实验研究

采用人工模拟降雨和室内分析相结合的方法,研究了黄土区不同耕作措施对降雨入渗的影响。结果表明：①不同耕作管理措施对降雨入渗的影响效用不同,在相同雨强和坡度下,降雨入渗速率表现为：耙耱地〉人工掏挖〉直线坡,在中小雨强和较短滞后情况下,这种情况表现更为显著;②不同耕作管理措施对降雨产流的影响效用不同,在相同雨强和坡度下,产流滞后表现为：耙耱地〉人工掏挖〉直线坡,在中小雨强和较短滞后情况下,这种情况表现更为显著;③根据水量平衡原理,得出了不同耕作管理措施不同坡度下入渗及产流滞后随雨强的变化关系式。上述结果为黄土高原坡耕地水土流失的治理和管理,提供了一定的理论依据。     

人工快速渗滤系统氨氮去除机理

通过对稳定运行的快渗池采样监测和利用室内人工土柱法研究了渗滤系统中氨氮、硝氮的分布和转化,探讨了人工快速渗滤系统(CRI)中氨氮的去除机理.结果显示,在布水期,人工快速渗滤系统中主要发生吸附反应,吸附态氨氮主要集中在0～50cm砂层;在落干期,吸附态氨氮发生硝化反应,在下一次布水时硝氮随水流排出;系统的反硝化能力较弱,总氮的去除率也较低.     

STRATIFICATION OF VARIABILITY IN RUNOFF AND SEDIMENT YIELD BASED ON VEGETATION CHARACTERISTICS1

ABSTRACT: Runoff and sediment yield were collected from 100 plots during simulated rainfalls (100 mm/hr for 15 minutes) at antecedent soil moisture conditions. A clustering technique was used to stratify the variability of a single data set within a sagebrush‐grass community into four groups based on vegetation life form and amount of cover. The four cluster groups were grass, grass/shrub, shrub, and forb/grass and were found to be significantly different in plant height, surface roughness, soil bulk density, and soil organic matter. Stepwise multiple regression analyses were performed on the single data set and each cluster group. Results for individual groups resulted in more robust predictive equations for runoff (r²= 0.65–0.73) and sediment yield (r²= 0.37–0.91) than for equations developed from the single data set (r²= 0.56 for runoff and r²= 0.27 for sediment yield). The standard errors of the cluster group regression equations were also improved in three of the four group equations for both runoff and sediment yield compared to the single data set. Runoff was found to be significantly less (p >0.01) in the forb/grass group compared with other vegetation cluster groups, but this was influenced by four plots that produced little or no runoff. Sediment yield was not found to be significantly different among any cluster groups. Discriminant analysis was then used to identify important variables and develop a model to classify plots into one of the four cluster groups. The discriminant model could be incorporated into rangeland hydrology and erosion models. The percentage cover of grasses, shrubs, litter, and bare ground effectively stratified about 12 percent of the variation observed in runoff and 26 percent of the variability for sediment yield as determined by r².     

垃圾渗滤液中DEHP与DBP的迁移演化规律研究

采用一维土柱下渗实验和垂向入渗模型相结合的方式,研究垃圾渗滤液中邻苯二甲酸二乙基己基酯（DEHP）和邻苯二甲酸二正丁酯（DBP）在土壤中的垂向迁移演化规律。结果表明：原状土和混有石英砂土的土柱对DBP的吸附能力均强于DEHP,而混有石英砂的土柱中DEHP、DBP均出现不同程度的穿透现象,且DEHP的穿透速度比DBP要快2倍;做或不做防渗处理,DEHP和DBP渗出量均呈前期快速增长而后期归于稳定的趋势,防渗对DBP效果较DEHP好;垂向入渗模型与一维土柱实验结果一致,该模型可用于其他区域有机污染物在土壤中垂向迁移的研究。     

一种新型湿地公园在水环境修复中的应用

近年来,利用人工湿地技术修复水环境,进而建设湿地公园成为一大热点,但人工湿地工艺存在不容忽视的缺陷。成都市凤凰河二沟湿地公园创新性的采用人工快渗+表面流人工湿地组合工艺修复水环境,两者互为补充,互为强化,COD、BOD5、氨氮、TP去除率分别达85%～95%、85%～95%、95%～98%、70%～80%,即使低温环境污染物降解效果也很稳定。     

白石砬子自然保护区几种主要植被类型土壤入渗特性研究

为了深入研究辽东山区森林土壤的水源涵养功能,以白石砬子自然保护区内的6种主要植被类型下土壤为研究对象,采用野外双环试验和室内理化性质分析相结合的方法,研究了不同植被类型下土壤入渗能力及其与理化性质的关系。结果表明,不同植被类型土壤的初渗率、稳渗率、平均入渗率、渗透总量均表现为下层低于上层,最大值是最小值的近3倍;不同植被类型间土壤入渗能力差异较大,其中A层初渗率排列顺序为原生红松阔叶混交林>红松人工林>鱼鳞云杉臭冷杉林>农地>蒙古栎林>杂木林,B层初渗率排列顺序为鱼鳞云杉臭冷杉林>农地>杂木林>红松人工林>原生红松阔叶混交林>蒙古栎林,A层稳渗率排列顺序为红松人工林>鱼鳞云杉臭冷杉林>原生红松阔叶混交林>杂木林>蒙古栎林>农地,B层稳渗率以杂木林最大,为3.8 mm?min-1,原生红松阔叶混交林最小,仅为1.1 mm?min-1,其他4种植被类型土壤稳渗率几乎无差异,A层平均入渗率排列顺序为红松人工林>原生红松阔叶混交林>鱼鳞云杉臭冷杉林>杂木林>蒙古栎林>农地,B层平均入渗率排列顺序为杂木林>鱼鳞云杉臭冷杉林>红松人工林>蒙古栎林>农地>原生红松阔叶混交林,A层的渗透总量以红松阔叶混交林和红松人工林最大,蒙古栎林和农地相对较低,B层的渗透总量以杂木林最大,红松阔叶混交林最小;主成分分析评价的土壤入渗能力排序为红松人工林>鱼鳞云杉臭冷杉林>原生红松阔叶混交林>杂木林>蒙古栎林>农地,初渗率、稳渗率、平均入渗率和渗透总量等4个指标综合起来能够很好的表达土壤入渗能力,其主成分方差的累积贡献率为90.662%;不同层次土壤入渗速率与入渗时间均存在良好的幂函数关系;土壤的稳渗率、平均入渗率、渗透总量与非毛管孔隙度呈显著正相关关系,初渗率与非毛管孔隙存在相关性,但不显著。与容重存在负相关关系,但不显著。     

基于节点水质监测的污水管网破损位置判定方法

提出基于管网检查井水质特征因子监测,并结合管网和污染源地理信息系统,解析污水管段的地下水入渗量和破损程度,以解决逐段物探或流量检测成本高且难以实施的问题.采用安赛蜜作为生活污水的水质特征因子,对安徽省巢湖市某污水厂服务范围（14.4km²）的污水管网系统地下水入渗量进行了空间分布解析,并识别出管网严重破损位置.结果表明：①基于划分管网节点的分段地下水入渗量解析,其总的入渗量解析结果与基于总体水量平衡的解析结果相对误差为21.0%,与典型管段流量监测结果的相对误差为5.4%,表明建立的方法是可靠的;②占污水管网总长0.3%的局部管段,其地下水入渗量占到总入渗水量的23.0%.因此,对局部破损管段进行修复,可以显著降低整个管网系统的破损程度.据此还提出了应用该方法的基本原则.     

Combined effect of fire and water scarcity on vegetation patterns in arid lands

In many arid zones around the word, the vegetation spontaneously forms regular patterns to optimize the use of the scarce water resources. The patterns act as early warning signal that fragile ecosystems may suddenly undergo irreversible shifts, thus, interpreting the structural shape of vegetation patterns is crucial to deciphering the ecosystem history and its expected further development. The sudden and irreversible shift of delicate ecosystems as a consequence of minor variation of the climatic forcing has been studied extensively in the past. The attitude of the ecosystem to recover after a catastrophic event, such as fire, did not receive as much attention so far. Here we modelled fire, as a sudden shift of the ecosystem state variables and functionality and evaluated post-fire scenarios under the hypothesis that two major feedbacks shaped the vegetation patterns: a positive feedback between preferential infiltration and plant growth, and a second feedback between infiltration and vegetation burning. A simple model solving a set of partial differential equations for soil moisture, plant biomass, surface water and dead biomass balance predicted significantly diverse post-fire vegetation patterns depending on the fire severity and on the degree of soil water repellency induced by the vegetation burning.     

城市生活垃圾渗滤液土地处理的模拟研究

通过静态与动态试验以及小试,从5种土壤中筛选出适合重庆地区垃圾渗滤液土地处理的基质土壤,确定了土地渗滤和芦苇湿地等两组土地处理系统净化城市垃圾渗滤液的有关参数,模拟处理结果表明垃圾渗滤液经两级土地处理后,春氨氮和CODcr的去除率均达到90%以上,出水水质达到国家一级排放标准。