Heavy Metals Removal from Swine Wastewater Using Constructed Wetlands with Horizontal Sub-Surface Flow

The removal efficiency of Cu and Zn from swine wastewater was evaluated as effected by three variables: the hydraulic retention time (HRT) (24, 48, 72 and 96 hours), two different plant species (Typha domingensis Pers. and Eleocharis cellulosa) and two different sizes of filter media (5 and 15 mm) using a horizontal sub-surface flow constructed wetland. From the results, a significant difference was observed in the removal efficiency of Cu and Zn with respect to different hydraulic retention times. The best results were obtained in the HRT of 96 hours for Zn where 96% removal of Zn with Typha domingensis Pers. specie with gravel of 15 mm (experimental unit 6) was achieved. For Cu, at 72 hours of HRT, the efficiency was nearly 100% in five of the six study units (1, 2, 3, 5 and 6). In contrast, in experimental unit 4 with gravel of 15 mm and without plants, only 86% Cu removal was achieved.

Performance of a Horizontal Flow Constructed Reed Bed Filter for Municipal Wastewater Treatment: The Case Study of the Prototype Installed at Gaston Berger University, Saint-Louis, Senegal

In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.

Spatial variations in daily average CO_2 concentrations above wetland surface of Xianghai National Nature Reserve, China

Horizontal and vertical variations of daily average CO 2 concentration above the wetland surface were studied in Xianghai National Nature Reserve of China in August, 2000 The primary purpose was to study spatial distribution characteristics of CO 2 concentration on the four levels of height(0 1 m, 0 6 m, 1 2 m and 2 m) and compare the differences of CO 2 concentration under different land covers. Results showed that daily average CO 2 concentration above wetland surface in Xianghai National Natural Reserve was lower than that above other wetlands in northeast China as well as the worldwide average, suggesting that Xianghai wetland absorbed CO 2 in August and acted as “sink” of CO 2 The horizontal variations on the four levels of height along the latitude were distinct, and had the changing tendency of “decreasing after increasing” with the increase of height. The areas with obvious variations were consistent on different levels of height, and those with the highest variations appeared above surface of shore, sloping field, Typha wetland and Phragmites wetland; the vertical variations were greatly different, with the higher variations in Phragmites wetland and Typha wetland, and the lands near the shore and the sloping field with the lower variations. Spatial variations of daily average CO 2 concentrations above wetland surface were affected by surface qualities and land covers.

Performance of hybrid constructed wetland systems for treating septic tank effluent

The integrated wetland systems were constructed by combining horizontal-flow and vertical-flow bed, and their purification efficiencies for septic tank effluent were detected when the hydraulic retention time （HRT） was 1 d, 3 d, 5 d under different seasons. The results showed that the removal efficiencies of the organics, phosphorus were steady in the hybrid systems, but the removal efficiency of total nitrogen was not steady due to high total nitrogen concentration in the septic tank effluent. The average removal rates of COD （chemical oxygen demand） were 89%, 87%, 83%, and 86% in summer, autumn, winter and spring, respectively, and it was up to 88%, 85%, 73%, and 74% for BOD5 （5 d biochemical oxygen demand） removal rate in four seasons. The average removal rates of TP （total phosphorous） could reach up to 97%, 98%, 95%, 98% in four seasons, but the removal rate of TN （total nitrogen） was very low. The results of this study also indicated that the capability of purification was the worst in winter. Cultivating with plants could improve the treated effluent quality fTom the hybrid systems. The results of the operation of the horizontal-flow and vertical-flow cells （hybrid systems） showed that the removal efficiencies of the organics, TP and TN in horizontal-flow and vertical-flow cells were improved significantly with the extension of HRT under the same season. The removal rate of 3 d HRT was obviously higher than that of 1 d HRT, and the removal rate of 5 d HRT was better than that of 3 d HRT, but the removal efficiency was not very obvious with the increment of HRT. Therefore, 3 d HRT might be recommended in the actual operation of the hybrid systems for economic and technical reasons.

Analysis of pollutant removal effect usinginnovative ridge-shaped constructed wetland

In this paper,a new type of ridge-shaped constructed wetland which combines surface flow and horizontal subsurface flow was proposed.The proposed wetland had simple structure,low construction and operating cost,less human interference and good pollution removal effect.The combination of surface flow and subsurface flow provided an aerobic and anaerobic alternating environment for the entire wetland.The performance of the proposed wetland was compared with a traditional horizontal subsurface flow wetland.The comparison results showed that the removal rates of BOD(biochemical oxygen demand),TN(total nitrogen),and TP(total phosphorus)in the ridge-shaped wetland increased up to 20.3%,17.0%,and 9.1%,respectively.The proposed wetland structure could be widely applied for treatment of rural and urban domestic sewage pollution or agricultural point and nonpoint source water pollution.

不同化学药剂对人工湿地基质堵塞的缓解效果与机理

以水平潜流人工湿地为研究对象,探究十二烷基硫酸钠(SDS)、次氯酸钠(NaClO)和过氧化氢(H_(2)O_(2))对基质堵塞的缓解效果与机理,并分析其工程应用可行性.结果表明,经过3种化学药剂处理后,基质层渗透系数分别提高53.3%、27.5%、210.7%.此外,H_(2)O_(2)对反应器污染物去除效率影响最小,并提高了NH_(4)+-N及TP的去除效果.3种药剂的投加对植物造成轻微伤害,但这种负面影响短期内(14d)可弹性恢复(93.8%、84.4%、84.4%).在微生物群落结构方面,化学药剂处理可以通过抑制生物膜形成细菌(如Pleomorphomonas属和norank_f__norank_o__Saccharimonadales属)的生长来缓解堵塞,并通过改善反应器厌氧环境促进脱氮除磷功能细菌(如反硝化细菌unclassified_f__Comamonadaceae)的生长来恢复反应器性能.结合堵塞缓解效果和工程应用可行性比较认为,3种药剂中H_(2)O_(2)为缓解人工湿地基质堵塞的最佳药剂.

两种基质下水平潜流人工湿地处理污水厂尾水的中试

为比较页岩陶粒和砾石两种基质的水平潜流人工湿地在不同水力负荷条件下对污染物的去除效果,搭建一套人工湿地中试装置对武汉某污水处理厂尾水进行处理,并通过高通量测序技术比较分析两种基质中的微生物群落结构。结果表明:水平潜流湿地在低水力负荷[0.3~0.6m^(3)/(m^(2)·d)]运行时,COD、NH3-N和TN得到较好的去除,而在高水力负荷[1.2m^(3)/(m^(2)·d)]运行时,TP的去除效果较好。与砾石水平潜流人工湿地相比,页岩陶粒水平潜流人工湿地在不同水力负荷下对污染物的去除效果较优,且湿地中的Pseudomonas、Flavobacterium、Arenimonas、Saccharimonadales、Paracoccus、Nitrospira、Terrimonas等功能菌属丰度更高,有利于湿地对污染物的去除。页岩陶粒水平潜流人工湿地对污水厂尾水的净化效率更高,建议根据实际情况进行工程应用。

某农村生活污水治理工程实例

针对农村生活污水水质特点,结合某农村生活污水实际情况,设计采用了“格栅池+调节池+A2O+人工湿地”组合工艺,其中生物处理段采用了A2O生物接触氧化工艺,湿地采用了垂直流+水平流人工湿地工艺。污水处理站点建成后,在设计进水水质的条件下,出水水质能稳定达到DB32/3462—2020一级A标准。该工艺对污染物处理效果好,可作为农村生活污水高标准治理技术进行推广。

生物生态技术处理农村生活污水案例分析

采用生物生态技术处理农村生活污水,将“化粪池+调节池+跌水复氧+水平潜流人工湿地+稳定塘”组合工艺应用于河南省灵宝市某村生活污水处理。连续运行中发现,该工艺具有较好的处理效果,COD、NH_(3)-N、TP等主要指标的平均去除率分别为72.8%、58.2%、55.1%,出水水质满足《河南省农村生活污水处理设施水污染物排放标准》(DB 41/1820-2019)二级标准,经处理的污水进入稳定塘暂存,并进行资源化利用不外排。本工程可为相似区域农村生活污水处理的技术选择和运行提供参考。

城市湿地公园的生态补水模式及其净化效果与生态效益

以常州市蔷薇湿地公园为例,提出一种"垂直流+水平流"新型生态补水复合模式,探讨了该模式的环境效应和经济效益.结果表明:该补水模式不但能净化受污染的源水(城市河水),而且可有效提升城市湿地公园的生态景观功能.城市湿地公园内的大部分景观水体可达到全身接触性娱乐类景观功能要求,运行成本仅为常规补水工艺的5～25,具有较好的环境效应和经济效益.

人工湿地基质微生物状况与净化效果相关分析

利用混菌法和稀释法,测定了不同植物以及无植物潜流水平湿地基质中微生物的数量。结果表明:不同植物湿地基质中微生物的数量差异不显著,有植物和无植物湿地的差别不明显;湿地基质中不同空间位置的微生物数量各不相同,一般上层多于下层;在湿地运行条件相对稳定的情况下,湿地基质中会逐渐形成数量和活性比较稳定的生物群落。分析了人工湿地基质中微生物数量与污水净化效果的关系。结果表明:微生物数量与BOD5及TN的去除有显著的相关性,说明微生物的作用是去除它们的重要途径;基质微生物数量与TP的去除率相关性不明显。测定了湿地基质硝化速率,其硝化能力与亚硝化细菌的数量呈显著相关。

潜流人工湿地对农村生活污水氮去除的研究

作者研究了潜流水平人工湿地处理农村生活污水中氮的去除效果,结果表明湿地进水TN负荷与出水TN负荷去除之间有较好的线性关系,随着水力停留时间的延长TN去除率也升高,停留时间为4d时,芦苇湿地和菖蒲湿地的脱氮效率可以达到60%以上。从脱氮效果看,芦苇湿地的略好于菖蒲湿地的,有植物系统明显好于无植物系统。在进水NO-2-N浓度小于0.062mg/L、N-3O-N浓度小于1.982mg/L的情况下,无论是连续运行还是间歇运行,大多数情况下,出水浓度都分别低于0.631mg/L和1.00mg/L,两者一般不会有较大的积累。试验分析了湿地脱氮的途径,微生物硝化/反硝化是人工湿地脱氮的主要途径,植物吸收、存储仅占湿地总氮去除量的10%左右,但是植物的存在间接地影响湿地脱氮的其它途径,对提高湿地氮去除率具有重要作用。

向海沼泽湿地土壤中硝态氮的水平运移规律

选择封闭性的付老文泡湿地和开放性的二百方子湿地作为两个典型区,以KNO3为示踪剂,模拟研究了硝态氮在向海沼泽湿地中的水平运移过程.结果表明,沼泽湿地土壤中硝态氮的运移通量与运移距离显著负相关,并随运移距离的增加呈一阶衰减指数变化;而沼泽湿地土壤中硝态氮的运移通量与土壤水扩散率及土壤含水量都呈显著正相关关系,并随土壤水扩散率的增加呈指数增长.

水平潜流和垂直流湿地处理蓟运河水的效果比较

为了改善蓟运河的水质,使其达到《地表水环境质量标准》(GB 3838—2002)中的Ⅳ类水质标准,在蓟运河北岸的空地上构建了水平潜流人工湿地和垂直流人工湿地,研究了其对河水的净化效果。为防止浮游藻类堵塞填料床,原水在进入人工湿地前先经加药气浮工艺预处理,当PAC的投加量为50 mg/L时,水平潜流人工湿地对COD、BOD5、SS、TN、NH3-N、TP的去除率分别为65%、50%、100%、70%、90%和65%,垂直流人工湿地对COD、BOD5、SS、TN、NH3-N、TP的去除率分别为45%、70%、100%、65%、95%、85%。两种人工湿地的出水水质均可以达到Ⅳ类标准,但考虑到冬季低温时,垂直流人工湿地的填料床极易发生冰冻的现象,所以建议采用水平潜流人工湿地处理蓟运河水。

波形潜流人工湿地污水处理技术研究

将波形潜流人工湿地(wavy subsurface flow constructed wetland,简称W-SFCW)在相同条件下与水平潜流人工湿地进行对比试验.W-SFCW床优化了传统潜流人工湿地的水流流态,使污水在W-SFCW床内进行波式流动,充分发挥了湿地系统降解污染物的能力.试验结果表明:W-SFCW在污染物去除方面明显优于传统潜流人工湿地.在相同试验条件下,W-SFCW对污水中COD,NH4+和TP的去除率分别比SFCW提高12.6％,22.0％和8.4％.

潮汐流及水平潜流人工湿地污水处理效果比较研究

利用室内潮汐流和水平潜流人工湿地装置,对不同类型人工湿地污染物的去除效果进行对比试验。结果表明:潮汐流人工湿地有利于CODCr和氨氮的去除,去除率分别达到94%和95%,灯芯草水平潜流人工湿中因为湿地植物吸收和根区效应等作用使其总氮去除率达到51%,CODCr和氨氮去除率分别为76%和49%,无植物水平潜流人工湿地中CODCr、氨氮和总氮去除率最差,分别为70%、34%和36%;潮汐运行方式可改善湿地内部的氧环境,提高微生物活性,潮汐流人工湿地中微生物活性达到0.3mg·g-1,是水平潜流人工湿地的近3倍;三组人工湿地基质微生物硝化作用强度与对应氨氮去除效果呈显著正相关关系,相关系数r=0.89(P<0.05),表明微生物的硝化作用是主要的氨氮脱除途径,且硝化作用强度可作为反映湿地氨氮脱除能力的一个重要指标。

三江平原典型小叶章湿地土壤中硝态氮水平运移的模拟研究

选择三江平原小叶章湿地不同水分带上草甸沼泽土和腐殖质沼泽土2种土壤类型作为研究对象,以KNO3为示踪剂,模拟研究硝态氮在湿地土壤中的水平运移过程。结果表明,2种土壤各土层硝态氮水平运移浓度和速率均与运移距离呈极显著负相关(P<0.01),并随运移距离增加呈一阶指数衰减曲线变化,各土层硝态氮水平运移速率主要受浓度梯度、水势梯度及土壤基质势的控制;土壤各土层中硝态氮水平运移速率与土壤含水量呈显著正相关(P<0.05),并随土壤含水量增加呈指数增长曲线变化;土壤各土层中硝态氮水平运移浓度与土壤水分扩散率呈极显著正相关(P<0.01),0—20 cm土层硝态氮水平运移浓度随水分扩散率升高呈Boltzm ann曲线变化,其他土层则呈指数增长曲线变化;草甸沼泽土比腐殖质沼泽土相应土层更利于硝态氮的水平运移,这主要与土层颗粒组成和孔隙度等物理性质的显著差异有关,而湿地水文条件可能对2种土壤物理性质的塑造有着重要影响。

塘-人工湿地生态系统处理城市地表径流的初期运行

以武汉市桃花岛塘和人工湿地组合生态处理系统为研究对象,探讨了该系统处理城市地表径流的初期运行,结果表明:塘和人工湿地组合生态系统可以有效的处理城市地表径流,复合潜流人工湿地系统具有独特的除氮效果。

水平流-垂直流复合人工湿地系统对污水的净化效果研究

采用人工处理池,将水平流与垂直流湿地系统组合成复合式人工湿地处理系统,研究了此系统在停留时间为5d时对城市污水的净化效果。结果表明,水平流-垂直流复合人工湿地系统处理效果相当稳定,其对化粪池出水中COD,BOD5,TP,TN,SS的平均去除率分别为72%,80%,83%,33%和60%以上。而种植系统去除效果明显高于无种植系统。

安徽省升金湖湿地土壤有机碳储存及分布

文章研究了安徽省升金湖湿地土壤有机碳储存和分布特征及其与土壤氮素的关系。结果表明,供试湿地土壤全土1m深有机碳密度达10.82±1.90kg.m-2,表层土壤(0—30cm)有机碳密度为5.19±0.68kg.m-2,高于报道的人工湿地——水稻土的碳密度;有机碳(SOC)含量分布随土壤深度(H)的递降符合幂函数方程,湿地土壤有机碳的表层积累强度和积累深度高于稻田;湿地土壤氮素是土壤固碳的有利因子,其氮素对土壤有机碳积累的效应高于水稻土;因湖泊沉积受河流动力学、土壤水分和植物生长条件的影响,湿地土壤有机碳含量存在显著的水平空间变异性。看来,长江中下游淡水湿地在陆地生态系统碳氮储存上具有重要意义。