Activities of Urease and Phosphatase in Integrated Vertical Flow Constructed Wetland and Purification Effect of Black and Malodorous River

[Objective]The activities of urease and phosphatase in integrated vertical flow constructed wetland and purification effect of black and malodorous river were studied.[Method]Honeycomb stone and soft filler were used as matrix,the biological grid integrated vertical flow constructed wetland system was built to strengthen treatment for black and malodorous river,and the activities of urease and phosphatase of two fillers in different functional areas of constructed wetland were tested to study the film formation property of two fillers in different functional areas.[Result]Both urease and phosphatase activities on biofilm of soft filler were significantly higher than on biofilm of honeycomb stone filler;indicating that choosing soft filler was more advantageous to the growth of biofilm;and urease activity had significant correlation with total nitrogen removal rate,while phosphatase activity had no significant correlation with total phosphorus removal rate.[Conclusion]This study provided evidences for utilizing the activities of urease and phosphatase to evaluate the purification effect of black and malodorous river and choose appropriate filler.

Effects of Hydraulic Loading of Vertical Flow Constructed Wetland Clogging

[Objective] The aim was to al eviate the constructed wetland clogging problems and to explore to the effects of hydraulic loading on wetland clogging. [Method] The experiment, through artificial soil columns, simulated vertical flow arti-ficial wetland, set four hydraulic load level at 50, 100, 150 and 200 cm/d, to identify the impact of hydraulic loading on wetland clogging and to explore the factors run-ning threshold. [Result] The results show that the different levels of hydraulic loading have greater impact; in the constructed wetland clogging process under high hy-draulic loading of 200 cm/d, the effective life was only six months, and the single factor can be speculated that the threshold of the hydraulic load should be at 100-150 cm/d; system can last for six months at low hydraulic loading and last for three months at medium hydraulic load. [Conclusion] The research provides references for wetland clogging experiments in future.

Treatment and utilization of septic tank effluent using vertical-flow constructed wetlands and vegetable hydroponics

Vertical flow constructed wetlands is a typical ecological sanitation system for sewage treatment. The removal rates for COD, BOD 5, SS, TN, and TP were 60%, 80%, 74%, 49% and 79%, respectively, when septic tank effluent was treated by vertical flow filter. So the concentration of COD and BOD\-5 in the treated effluent could meet the quality standard for irrigation water. After that the treated effluent was used for hydroponic cultivation of water spinach and romaine lettuce, the removal efficiencies of the whole system for COD, BOD\-5, SS, TN and TP were 71 4%, 97 5%, 96 9%, 86 3%, and 87 4%, respectively. And it could meet the integrated wastewater discharge standard for secondary biological treatment plant. It was found that using treated effluent for hydroponic cultivation of vegetables could reduce the nitrate content in vegetables. The removal rates for total bacteria and coliform index by using vertical flow bed system with cinder substrate were 80%—90% and 85%—96%, respectively.

Enhancing treatment efficiency of swine wastewater by effluent recirculation in vertical-flow constructed wetland

Livestock wastewater has been a major contributor to Chinese cultural eutrophication of surface waters. Constructed wetlands are under study as a best management practice to treat wastewater from dairy and swine operations, but the removal efficiency of pollutants is relatively low. Enhancing the treatment efficiency of livestock wastewater by effluent recirculation was investigated in a pilot-scale vertical-flow constructed wetland. The wetland system was composed of downflow and upflow stages, on which narrow-leaf Phragmites communis and common reed Phragraites Typhia are planted, respectively; each stage has a dimension of 4 m^2 （2 m × 2 m）. Wastewater from facultative pond was fed into the system intermittently at a flow rate of 0.4 m^3/d. Recirculation rates of 0, 25%, 50%, 100% and 150% were adopted to evaluate the effect of the recirculation rate on pollutants removal. It shows that with effluent recirculation the average removal efficiencies of NH4-N, biological oxygen demand （BOD5） and suspended solids（SS） obviously increase to 61.7%, 81.3%, and 77.1%, respectively, in comparison with the values of 35.6%, 50.2%, and 49.3% without effluent recirculation. But the improvement of TP removal is slight, only from 42.3% to 48.9%. The variations of NH4-N, dissolved oxygen（DO） and oxidation-reduction potential（ORP） of inflow and outflow reveal that the adoption of effluent recirculation is benefi- cial to the formation of oxide environment in wetland. The exponential relationships with excellent correlation coefficients （R2 〉0.93） are found between the removal rates of NH4-N and BOD5 and the recirculation rates. With recirculation the pH value of the outflow decreases as the alkalinity is consumed by gradually enhanced nitrification process. When recirculation rate is kept constant 100%, the ambient temperature appears to affect NH4-N removal, but does not have significant influence on BOD5 removal.

Application of High-efficient Vertical Flow Constructed Wetland in Treatment of Domestic Sewage in Residential Community

With the increase of requirement for ecological function of environment,for quality of water environment,for sewage treatment cost and for comprehensive utilization of water resources,it was bound to introduce a new type of ecological technology for pollution treatment which was low in cost,convenient in management and stable in operation.High-efficient vertical flow constructed wetland developed by Shenzhen Academy of Environmental Science was characterized by good landscape effect and high efficiency of pollutants removal,and it had been widely applied in sewa-ge treatment and recycling and in lake water circulation purification.A lot of practical results showed that this technology could achieve high removal efficiency of SS,COD,BOD5,NH4-N and TP and the removal rate had arrived at more than 80% when hydraulic loading was 0.33-0.50 m/d.Effluent quality had met the water quality standard for recycling of urban sewage.

Effects of Cd^(2+) and Pb^(2+) on the substrate biofilms in the integrated vertical-flow constructed wetland

The effects of single Cd^(2+)and Pb^(2+),and combined Cd^(2+)and Pb^(2+)on dehydrogenase activity and polysaccharide content of the substrate biofilms in the integrated vertical-flow constructed wetland(IVCW)were studied.Dehydrogenase activities decreased linearly with the increasing concentrations of Cd^(2+)and Pb^(2+)at different times(6,24,72,and 120 h).The activities at both 6 and 24 h were significantly higher than that at 72 and 120 h in the case of single and combined treatments.The single Cd^(2+)and...

Phosphorus and Nitrogen Removal by Saturated Vertical-Flow Constructed Wetlands (SVCWs) Type Micro-Pilot Using Shale from Ivory Coast as a Substrate

This study evaluates the performance of shale from Ivory Coast used as substrate in vertical-flow constructed wetlands in removal of phosphates and nitrogen. The pilot-scale artificial wetland has been duplicated: filter planted with Panicum maximun and unplanted. They were set up outdoors, and fed with a municipal wastewater. The wetlands have been fed with three batches per week (intermittent) over a period of 3 months. During the operation period, the hydraulic residence time (HRT) 52 h was used, while wastewater temperatures varied from about ~33°C. The removal performance of the constructed wetland units was very good, since it reached on an average 98%, 89.4%, 89.4%, 84%, 80%, 84.8% and 92% for TSS, DOC, BOD5, , TKN, TP and respectively. In addition, the vegetation did not demonstrate superior performance to unplanted controls. Therefore, this study focuses on the role of shale in the phosphorus and nitrogen removal from wastewater by constructed wetland.

Significance of Primary Treatment Selection in the Efficiency of Wastewater Treatment in Constructed Wetlands (CWs)

This research explores strategies to enhance the efficiency of secondary treatment in Vertical Flow Constructed Wetlands (CW) in Montenegro. The focus is on selecting appropriate primary treatment methods alongside three distinct substrate types to improve wastewater treatment efficacy. The study examines the combination of two primary treatments with different substrate types in constructed wetlands (CW1, CW2, and CW3). The primary treatments include the existing wastewater treatment plant (WWTP) in Podgorica, involving coarse material removal through screens, inert material separation in aerated sand traps, and sediment and suspended matter removal in primary sedimentation tanks. The Extreme Separator (ExSep) was employed to evaluate its efficacy as a primary treatment method. The research demonstrates that the efficiency of CW can be significantly enhanced by selecting suitable primary treatment methods and substrates in Podgorica’s conditions. The most promising results were achieved by combining ExSep as a primary treatment with secondary treatment in CW-3. The removal efficiencies after CW3 for COD, BOD, and TSS exceeded 89%, 93%, and 91%, respectively. The outcomes underscore the significance of primary treatment in mitigating pollutant loads before discharge into the constructed wetlands, emphasizing potential areas for further optimization in wastewater treatment practices to enhance environmental sustainability and water quality management.

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.

Significance of Substrate Selection in the Efficiency of Wastewater Treatment in Constructed Wetlands (CWs)

Constructed wetlands (CWs) can achieve a high-quality wastewater treatment and a quality that meets the prescribed standard, defined by legislation on wastewater discharge. A limitation in the application of constructed wetlands (CWs) is the large area requirement, which limits their application. The subject matter of this research is to check the possibility of improving the efficiency of wastewater treatment and reducing the required area for constructed wetlands (CWs) by using an adequate substrate under the conditions found in Montenegro. In the described experiment, the constructed wetlands (CW) have a vertical flow system and play the role of a secondary wastewater treatment, receiving water from the existing WWTP in Podgorica after the primary treatment. These vertical flow systems reflect experience with the use of similar systems in Slovenija, Austria and Italy. Measurements to date show that the substrate plays an important role and that wastewater treatment efficacy varies significantly with respect to the type of substrate when used under the conditions available in Montenegro.

Effect of artificial aeration on the performance of vertical-flow constructed wetland treating heavily polluted river water

Three lab-scale vertical-flow constructed wetlands （VFCWs）, including the non-aerated （NA）, intermittently aerated （IA） and continuously aerated （CA） ones, were operated at different hydraulic loading rates （HLRs） to evaluate the effect of artificial aeration on the treatment efficiency of heavily polluted river water. Results indicated that artificial aeration increased the dissolved oxygen （DO） concentrations in IA and CA, which significantly favored the removal of organic matter and NH4＋-N. The DO grads caused by intermittent aeration formed aerobic and anoxic regions in IA and thus promoted the removal of total nitrogen （TN）. Although the removal efficiencies of CODEr, NH4＋-N and TN in the three VFCWs all decreased with an increase in HLR, artificial aeration enhanced the reactor resistance to the fluctuation of pollutant loadings. The maximal removal efficiencies of CODEr, NH4＋-N and total phosphorus （TP） （i.e., 81%, 87% and 37%, respectively） were observed in CA at 19 cm/day HLR, while the maximal TN removal （i.e., 57%） was achieved in IA. Although the improvement of artificial aeration on TP removal was limited, this study has demonstrated the feasibility of applying artificial aeration to VFCWs treating polluted river water, particularly at a high HLR.

Decontamination efficiency and root structure change in the plant-intercropping model in vertical-flow constructed wetlands

Subtropical climatic conditions can contribute to the death of the aerial parts of constructed wetland plants in winter. This presents a barrier to the widespread application of constructed wetland and is an issue that urgently needs to be solved. Three contrasting experi- ments, the plant-intercropping model （A）, the warm- seasonal plant model （B）, and the non-plant model （C）, were studied in terms of their efficiency in removing pollutants, and the change in root structure of plants in the plant-intercropping model within the vertical-flow con- structed wetlands. The results indicate that model A was able to solve the aforementioned problem. Overall, average removal rates of three pollutants （CODcr, total nitrogen （TN） and total phosphorous （TP）） using model A were significantly higher than those obtained using models B and C （P 〈 0.01）. Moreover, no significant differences in removal rates of the three pollutants were detected between A and B during the higher temperature part of the year （P〉 0.05）. Conversely, removal rates of the three pollutants were found to be significantly higher using model A than those observed using model B during the lower temperature part of the year （P 〈 0.01）. Furthermore, the morphologies and internal structures of plant roots further demonstrate that numerous white roots, whose distribution in soil was generally shallow, extend further under model A. The roots of these aquatic plants have an aerenchyma structure composed of parenchyma cells, therefore, roots of the cold-seasonal plants with major growth advantages used in A were capable of creating a more favorable vertical-flow constructed wetlands media- microenvironment. In conclusion, the plant-intercropping model （A） is more suitable for use in the cold environment experienced by constructed wetland during winter.

Treatment Efficiency of Integrated Vertical-Flow Constructed Wetland for Saline Wastewater

The integrated vertical-flow constructed wetland（IVCW） was simulated with three suits of designed experiment columns planted with Kandelia candel.Units A,B and C were irrigated with sewage of different salinity（A：10‰ B：20‰,C：30‰）,respectively.The removal rates of dissolved organic carbon（DOC）,NH3-N and NO3--N dropped 90.4%-48.6%,80.2%-40.3% and 84.8%-60.9%,respectively,when salinity increases from 10‰ to 30‰.The removal rate of TP increased 14%-31.2%,oppositely.A 20-day inflow salinity drastic change shock affective trial was done on units D and E.Unit D was used as a control and irrigated with saline sewage（20‰）.Unit E was irrigated with sewage with low salinity（5‰） as a salinity drastic change shock on the third and fourth days.DOC,NH3-N and NO3--N removal efficiency of unit E showed a three-stage process of change,＂rapidly decrease,increase beyond the normal standard,and then back to the normal standard＂.TP removal value was negative during the 2-day shock period.

Hybrid constructed wetlands for highly polluted river water treatment and comparison of surface-and subsurface-flow cells

A series of large pilot constructed wetland （CW） systems were constructed near the confluence of an urban stream to a larger fiver in Xi＇an, a northwestern megacity in China, for treating polluted stream water before it entered the receiving water body. Each CW system is a combination of surface- and subsurface-flow cells with local gravel, sand or slag as substrates and Phragmites australis and Typha orientalis as plants. During a one-year operation with an average surface loading of 0.053 m3/（m2.day）, the overall COD, BOD, NH3-N, total nitrogen （TN） and total phosphorus （TP） removals were 72.7% ~ 4.5%, 93.4% ＋ 2.1%, 54.0% ＋ 6.3%, 53.9% ~ 6.0% and 69.4% ：t： 4.6%, respectively, which brought about an effective improvement of the fiver water quality. Surface-flow cells showed better NH3-N removal than their TN removal while subsurface-flow cells showed better TN removal than their NH3-N removal. Using local slag as the substrate, the organic and phosphorus removal could be much improved. Seasonal variation was also found in the removal of all the pollutants and autumn seemed to be the best season for pollutant removal due to the moderate water temperature and well grown plants in the CWs.

垂直潜流人工湿地净化水中镉、氮、磷效果及机理

矿山区域因降雨形成含镉(Cd)、氮(N)和磷(P)混合废水,对生态和人类构成威胁,本文探求一种高效人工湿地净化装置并进行机理研究。设置“生物炭(BC)+土壤+菖蒲”试验装置(CWSPB),选择“土壤+菖蒲”(CWSP)与“BC+土壤”(CWSB)装置对照。结果表明,CWSPB对Cd、NH_(4)^(+)-N和TP去除效果最好,平均去除率分别为98.65%±1.90%、72.77%±19.35%和74.46%±16.06%。CaCl_(2)和Tessier提取法表明CWSPB土壤中Cd稳定性最好。FTIR和XPS分析表明,BC表面官能团-COOH、-OH和-C=O以及离子HPO_(4)^(2-)、PO_(4)^(3-)、OH^(-)、CO_(3)^(2-)参与Cd去除。微生物群落分析表明门水平细菌变形菌、拟杆菌、厚壁菌和真菌担子菌、毛霉菌及属水平细菌普雷沃氏菌、不动杆菌和真菌青霉菌、曲霉菌、木霉菌、紫球菌相对丰度增加明显。研究显示由BC、土壤和菖蒲组成的人工湿地在处理Cd、N、P废水有较好效果与潜力。

生物转盘耦合垂直流人工湿地对生活污水的净化效果及其微生物群落结构特征

为提高垂直流人工湿地对农村生活污水的净化效率,构建生物转盘耦合垂直流人工湿地系统。以实际生活污水为对象,研究耦合系统对生活污水的净化效果,并采用高通量测序分析其微生物群落结构特征,揭示微生物群落结构与污染物处理效率之间的关系。结果表明:系统对化学需氧量(COD)、氨氮(NH_(4)^(+)-N)和总磷(TP)的去除率分别为64.97%、86.84%和79.18%,出水平均质量浓度分别为71.70、3.21和0.67 mg·L^(-1);新型湿地系统适于处理COD、ρ(NH_(4)^(+)-N)和ρ(TP)分别为<250、30~50和<2 mg·L^(-1)的生活污水,且24 h为系统最佳运行时间;2个系统中不同填料区微生物种类无较大差别,相对丰度差别较大,共有的优势菌门、优势菌纲和优势菌目分别有5、8和10类,系统中除氮微生物主要为氢噬胞菌属(Hydrogenophaga)、假单胞菌属(Pseudomonas)等,除磷功能微生物主要有假单胞菌属、脱氯单胞菌(Dechloromonas)、不动杆菌属(Acinetobacter)、红球菌属(Rhodococcus)等;细菌群落影响污染物的去除,NH_(4)^(+)-N、TP和COD去除率与变形菌门和蓝细菌门呈显著正相关,TP浓度与绿弯菌门、COD与绿菌门呈显著正相关(P<0.05);各污染物主要在火山石区、沸石区被去除。研究结果明确了生物转盘耦合垂直流人工湿地微生物群落结构特征及其与污染物去除之间的关系,可为进一步提高人工湿地的处理效率提供科学参考。

Performance of different macrophytes in the decontamination of and electricity generation from swine wastewater via an integrated constructed wetland-microbial fuel cell process

Plants constitute a major element of constructed wetlands(CWs).In this study,a coupled system comprising an integrated vertical flow CW(IVCW) and a microbial fuel cell(MFC) for swine wastewater tre atment was developed to research the effects of macrophytes commonly employed in CWs,Canna indica,Acorus calamus,and Ipomoea aquatica,on decontamination and electricity production in the system.Because of the different root types and amounts of oxygen released by the roots,the rates of chemical oxygen demand(COD) and ammonium nitrogen(NH4^+-N) removal from the swine wastewater differed as well.In the unplanted,Canna indica,Acorus calamus,and Ipomoea aquatica systems,the COD removal rates were 80.20%,88.07%,84.70%,and 82.20%,respectively,and the NH4+-N removal rates were 49.96%,75.02%,70.25%,and 68.47%,respectively.The decontamination capability of the Canna indica system was better than those of the other systems.The average output voltages were 520±42,715±20,660±27,and 752±26 mV for the unplanted,Canna indica,Acorus calamus,and Ipomoea aquatica systems,respectively,and the maximum power densities were 0.2230,0.4136,0.3614,and0.4964 W/m^3,respectively.Ipomoea aquatica had the largest effect on bioelectricity generation promotion.In addition,electrochemically active bacteria,Geobacter and Desulfuromonas,were detected in the anodic biofilm by high-throughput sequencing analysis,and Comamonas(Proteobacteria),which is widely found in MFCs,was also detected in the anodic biofilm.These results confirmed the important role of plants in IVCW-MFCs.

两种不同基质的垂直潜流人工湿地对尾水的处理效果研究

为提高人工湿地对污水处理厂尾水的处理效率,采用以黄铁矿和砾石为基质的两种垂直潜流人工湿地处理武汉某污水处理厂尾水,研究了不同水力负荷下人工湿地去除污染物的效果,并分析了基质的微生物群落结构。结果表明,在低水力负荷(0.4~0.7 m^(3)/(m^(2)·d))下,两种人工湿地对尾水化学需氧量(COD)、总氮(TN)、NO_(3)^(-)和总磷(TP)具有较好的去除效果;在高水力负荷(1.0~1.3 m^(3)/(m^(2)·d))下,对氨氮去除效果较好。黄铁矿人工湿地对尾水COD、TN、NO_(3)^(-)和TP的去除效果好于砾石,分析基质微生物发现,黄铁矿人工湿地中反硝化脱氮菌属主要为硫杆菌属(Thiobacillus)和硫氧化菌属(Sulfurifustis),相对丰度分别为16.68%和4.62%,且硫杆菌属具有提高磷去除能力的功能;而砾石人工湿地中反硝化脱氮菌属主要为类固醇杆菌属(Steroidobacter),相对丰度为4.56%,采用黄铁矿为基质后,人工湿地中的脱氮除磷菌丰度和多样性升高,有利于人工湿地对尾水的脱氮除磷。黄铁矿人工湿地出水存在SO_(4)^(2-)含量偏高的现象,建议工程应用中在人工湿地底部填充黄铁矿以达到出水SO_(4)^(2-)含量降低的目的。

光催化、电场、磁场耦合垂直流人工湿地对生活污水的处理效果及微生物群落组成特征

为提高人工湿地对生活污水中污染物的有效去除,强化工艺耦合人工湿地已成为近年来的研究热点,通过构建的光催化、电场、磁场耦合垂直流人工湿地,探究该人工湿地对污水中化学需氧量(COD_(cr))、氨氮(NH_(4)^(+)-N)、总磷(TP)和正磷(PO_(4)^(3)-P)的去除效果,分析了各单元微生物群落的组成特征。结果表明:加入光催化、电场、磁场后,COD_(cr)、NH_(4)^(+)-N、TP和PO_(4)^(3)-P的去除率分别是71.1%、95.5%、54.3%、52.4%,可提高对COD_(cr)、NH_(4)^(+)-N的去除效果,与普通人工湿地相比,COD_(cr)的去除率可提高8.6%~22.4%,NH_(4)^(+)-N去效率可提高6.3%~30.0%,未能提高TP和PO_(4)^(3)-P的去除效果;光催化单元促进了光能异养微生物蓝细菌门(Cyanobacteria)、绿弯菌门(Chloroflexi)、集球藻菌纲(Synechococcophycideae)、绿丝菌属(Chloronema)的生长代谢,提升了嗜热型微生物纤发鞘丝蓝细菌属(Leptolyngbya)的活性,电、磁场单元促进了脱氮除磷微生物变形菌门(Proteobacteria)的生长代谢,提升了硝化功能菌不动杆菌属(Acinetobacter)、硝化螺旋菌属(Nitrospira)的活性。可见,光催化、电场、磁场单元与垂直流人工湿地耦合后,可使光合异养细菌和除氮细菌的丰度增加,提升COD_(cr)、NH_(4)^(+)-N的去除效果,偏高的电、磁场强度可能影响到磷素的基质吸附沉淀作用。