Use of engineered wetlands for onsite treatment of wastewater by the local communities: Experiences from Tanzania

2011 ◽  
Vol 6 (3) ◽  
Author(s):  
K. N. Njau ◽  
W. J. S. Mwegoha ◽  
R. J. Kimwaga ◽  
J. H. Y. Katima
Keyword(s):  
Constructed Wetlands ◽  
Domestic Wastewater ◽  
Industrial Effluents ◽  
Surface Flow ◽  
Pollutant Removal ◽  
Paper Mills ◽  
Waste Stabilization Ponds ◽  
Teachers College ◽  
Operation And Maintenance ◽  
Wide Range

Since its inception about 10 years ago, Constructed Wetlands (CWs) technology has been well received in Tanzania due to a wide range of functions. CWs are used to treat wastewater from municipal systems, pulp and paper industries, prisons, schools and colleges. Among the recipients of CWs are the Moshi Urban Water and Sewerage Authority (MUWSA) for polishing Waste Stabilization Ponds effluents, Kibo Paper Mills for treating industrial effluents, Shinyanga, Malya and Bariadi Prison and Kleruu Teachers College and Ruaha High School for Treatment of domestic wastewater. All these systems are Horizontal Sub-Surface Flow Constructed Wetlands. This paper reports on results of a survey of the six (6) mentioned operating CW systems, focusing on the existing situation and the observed operation and maintenance challenges and needs. The survey was carried by visiting the CWs and sampling for determination of BOD5, COD, PO42-, NO3-N, and NH3-N. Results from the survey and laboratory analyses in three of these CWs indicated lack of general and site-specific operation and maintenance guidelines, which seriously affect life of these systems, aesthetics and performance of pollutant removal. This is evidenced by failure of these systems to meet local and international permissible discharge limits to the receiving water bodies.

scholarly journals Treatment performances of French constructed wetlands: results from a database collected over the last 30 years

2015 ◽  
Vol 71 (9) ◽  
pp. 1333-1339 ◽  
Author(s):  
A. Morvannou ◽  
N. Forquet ◽  
S. Michel ◽  
S. Troesch ◽  
P. Molle
Keyword(s):  
Constructed Wetlands ◽  
Oxygen Demand ◽  
Pollutant Removal ◽  
Vertical Flow ◽  
Removal Rates ◽  
Waste Stabilization Ponds ◽  
Small Communities ◽  
Technical Department ◽  
In Series ◽  
High Chemical Oxygen Demand

Approximately 3,500 constructed wetlands (CWs) provide raw wastewater treatment in France for small communities (<5,000 people equivalent). Built during the past 30 years, most consist of two vertical flow constructed wetlands (VFCWs) in series (stages). Many configurations exist, with systems associated with horizontal flow filters or waste stabilization ponds, vertical flow with recirculation, partially saturated systems, etc. A database analyzed 10 years earlier on the classical French system summarized the global performances data. This paper provides a similar analysis of performance data from 415 full-scale two-stage VFCWs from an improved database expanded by monitoring data available from Irstea and the French technical department. Trends presented in the first study are confirmed, exhibiting high chemical oxygen demand (COD), total suspended solids (TSS) and total Kjeldahl nitrogen (TKN) removal rates (87%, 93% and 84%, respectively). Typical concentrations at the second-stage outlet are 74 mgCOD L−1, 17 mgTSS L−1 and 11 mgTKN L−1. Pollutant removal performances are summarized in relation to the loads applied at the first treatment stage. While COD and TSS removal rates remain stable over the range of applied loads, the spreading of TKN removal rates increases as applied loads increase.

scholarly journals Constructed wetlands in the treatment of agro-industrial wastewater: A review

2015 ◽  
Vol 69 (2) ◽  
pp. 127-142 ◽  
Author(s):  
Mar-Yam Sultana ◽  
Christos Akratos ◽  
Dimitrios Vayenas ◽  
Stavros Pavlou
Keyword(s):  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Municipal Wastewater ◽  
Industrial Effluents ◽  
Design Tool ◽  
Pollutant Removal ◽  
Toxic Substances ◽  
Wetland Type ◽  
Industrial Wastewaters ◽  
Hostile Environments

Due to their simplicity and low operation cost, constructed wetlands are becoming more prevalent in wastewater treatment all over the world. Their range of applications is no longer limited to municipal wastewater but has expanded to the treatment of heavily polluted wastewaters such as agro-industrial effluents. This paper provides a comprehensive literature review of the application of constructed wetlands in treating a variety of agro-industrial wastewaters, and discusses pollutant surface loads and the role of constructed wetland type, prior-treatment stages and plant species in pollutant removal efficiency. Results indicate that constructed wetlands can tolerate high pollutant loads and toxic substances without losing their removal ability, thus these systems are very effective bio-reactors even in hostile environments. Additionally, the review outlines issues that could improve pollutant treatment efficiency and proposes design and operation suggestions such as suitable vegetation, porous media and constructed wetland plain view. Finally, a decision tree for designing constructed wetlands treating agro-industrial wastewaters provides an initial design tool for scientists and engineers.

scholarly journals XỬ LÝ NƯỚC THẢI SINH HOẠT BẰNG ĐẤT NGẬP NƯỚC NHÂN TẠO NỀN XỈ THAN TỔ ONG KẾT HỢP TRỒNG CỎ VOI

2021 ◽  
Vol 5 (3) ◽  
pp. 2596-2605
Author(s):  
Kim Lavane ◽  
Nguyễn Thị Hoàng Hạnh ◽  
Phạm Văn Toàn
Keyword(s):  
Constructed Wetlands ◽  
Subsurface Flow ◽  
Domestic Wastewater ◽  
Pollutant Removal ◽  
Napier Grass ◽  
National Standard ◽  
Pennisetum Purpureum ◽  
Good Growth ◽  
Standard Type ◽  
Experimental Systems

Nghiên cứu này nhằm đánh giá hiệu suất của đất ngập nước (ĐNN) nhân tạo dòng chảy ngầm theo phương ngang (HSSF) và phương đứng (VF) có vật liệu nền là xỉ than tổ ong và trồng cỏ voi. Thí nghiệm được tiến hành trên mô hình phòng thí nghiệm với lưu lượng nạp của nước thải sinh họat là 85 lít/ngày. Tải lượng nạp BOD5, COD, TN, TP vào mô hình lần lượt là 7,47 g/m2.ngày, 3,17 g/m2.ngày, 1,43 g/m2.ngày, 0,12 g/m2.ngày. Kết quả nghiên cứu cho thấy nồng độ các chỉ tiêu ô nhiễm sau xử lý giảm đáng kể và đạt loại A theo QCVN 14:2008/BTNMT trong cả hai mô hình HSSFCW và VFCW. Hiệu suất xử lý của HSSFCW và VFCW đối với các chỉ tiêu lần lượt là SS: 88,7% và 92,4%; BOD5: 95,3% và 92,6%; COD: 94,3% và 92,6%; TN: 54,1% và 47,5%; N-NO3-: 38,4% và 33,6%; TP: 73,5% và 63,2%; P-PO43-: 87,6% và 59,7%. Nhìn chung, mô hình HSSFCW có hiệu suất loại bỏ các chất ô nhiễm tương đối cao hơn mô hình VFCW, ngoại trừ chỉ tiêu SS. Cỏ voi phát triển tốt và cho sinh khối cao trong thí nghiệm. Từ kết quả nghiên cứu cho thấy xỉ than tổ ong có thể tái sử dụng làm chất nền trong ĐNN nhân tạo dòng chảy ngầm. Bên cạnh đó, cỏ voi có thể trồng trong hệ thống ĐNN dòng chảy ngầm xử lý nước thải sinh hoạt. ABSTRACT This study aimed to evaluate the performances of horizontal subsurface flow (HSSF) and vertical flow (VF) constructed wetlands (CW) using combusted beehive charcoal residues as filtration bed media and planted with Napier grass (Pennisetum purpureum). The experimental systems were fed with a flow rate of 85 m3/day. The loading rates of BOD5, COD, TN, TP into the system were 7.47 g/m2.day, 3.17 g/m2.day, 1.43 g/m2.day, 0.12 g/m2.day, respectively. The results showed that the concentration of pollutants in effluents is significantly reduced and meet the national standard type A of QCVN 14:2008/BTNMT in both HSSFCW and VFCW models. The removal efficiencies in HSSFCW and SVFCW for SS: 88.7% and 92.4%; BOD5: 95.3% and 92.6%; COD: 94.3% and 92.6%; TN: 54.1% and 47.5%; N-NO3-: 38.4% and 33.6%; TP: 73.5% and 63.2%; P-PO43-: 87.6% and 59.7%, respectively. In general, the HSSFCW model has a relatively higher pollutant removal efficiency than the VFCW model, except for the SS. good growth and high biomass yield of Napier grass had been observed in the experimental systems. This study suggested that combusted beehive charcoal residues could be reused as bed substrate in constructed wetlands. Besides, Napier grass might also be a potential plant associated with subsurface flow constructed wetlands to treat domestic wastewater.

The Use of Submerged Structured Packings in Biofilm Reactors for Wastewater Treatment

1992 ◽  
Vol 26 (3-4) ◽  
pp. 723-731 ◽  
Author(s):  
G. Ryhiner ◽  
B. Birou ◽  
H. Gros
Keyword(s):  
Suspended Solids ◽  
Domestic Wastewater ◽  
Industrial Effluents ◽  
Water Production ◽  
Wastewater Purification ◽  
Biofilm Reactors ◽  
Wide Range ◽  
Solids Retention ◽  
Structured Packings ◽  
Pollution Removal

Structured packings are utilized as biomass carriers in new types of biofilm reactors. These systems have been tested and characterized for a wide range of applications, e.g. carbonaceous and nitrogenous pollution removal of domestic wastewater, purification of industrial effluents, etc. Their efficiency is discussed in terms of eliminated loads and suspended solids retention, as well as with respect to the factors influencing the costs of operation: head loss, backwash frequency, sludge water production. Design considerations of full scale units include both process-related parameters and technological aspects.

Constructed Wetlands for Industrial Wastewater Treatment and Removal of Nutrients

2020 ◽  
pp. 559-587
Author(s):  
David de la Varga ◽  
Manuel Soto ◽  
Carlos Alberto Arias ◽  
Dion van Oirschot ◽  
Rene Kilian ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetlands ◽  
Nutrient Removal ◽  
Industrial Wastewater ◽  
Low Cost ◽  
Domestic Wastewater ◽  
Industrial Effluents ◽  
Industrial Wastewater Treatment ◽  
Sustainable Systems ◽  
Domestic Wastewater Treatment

Constructed Wetlands (CWs) are low-cost and sustainable systems for wastewater treatment. Traditionally they have been used for urban and domestic wastewater treatment, but in the last two decades, the applications for industrial wastewater treatment increased due to the evolution of the technology and the extended research on the field. Nowadays, CWs have been applied to the treatment of different kind of wastewaters as such as refinery and petrochemical industry effluents, food industry effluents including abattoir, dairy, meat, fruit and vegetables processing industries, distillery and winery effluents, pulp and paper, textile, tannery, aquaculture, steel and mixed industrial effluents. In this chapter, the authors present the main types of CWs, explain how they work and the expected performances, and describe the principal applications of CWs for industrial wastewater treatment with particular attention to suspended solids, organic matter and nutrient removal. A review of these applications as well as some case studies will be discussed.

Evaluation of constructed wetlands by wastewater purification ability and greenhouse gas emissions

2007 ◽  
Vol 56 (3) ◽  
pp. 49-55 ◽  
Author(s):  
P. Gui ◽  
R. Inamori ◽  
M. Matsumura ◽  
Y. Inamori
Keyword(s):  
Plant Growth ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Seasonal Changes ◽  
Free Water ◽  
Domestic Wastewater ◽  
Pollutant Removal ◽  
Gas Emissions

Domestic wastewater is a significant source of nitrogen and phosphorus, which cause lake eutrophication. Among the wastewater treatment technologies, constructed wetlands are a promising low-cost means of treating point and diffuse sources of domestic wastewater in rural areas. However, the sustainable operation of constructed wetland treatment systems depends upon a high rate conversion of organic and nitrogenous loading into their metabolic gaseous end products, such as N2O and CH4. In this study, we examined and compared the performance of three typical types of constructed wetlands: Free Water Surface (FWS), Subsurface Flow (SF) and Vertical Flow (VF) wetlands. Pollutant removal efficiency and N2O and CH4 emissions were assessed as measures of performance. We found that the pollutant removal rates and gas emissions measured in the wetlands exhibited clear seasonal changes, and these changes were closely associated with plant growth. VF wetlands exhibited stable removal of organic pollutants and NH3-N throughout the experiment regardless of season and showed great potential for CH4 adsorption. SF wetlands showed preferable T-N removal performance and a lower risk of greenhouse gas emissions than FWS wetlands. Soil oxidation reduction potential (ORP) analysis revealed that water flow structure and plant growth influenced constructed wetland oxygen transfer, and these variations resulted in seasonal changes of ORP distribution inside wetlands that were accompanied by fluctuations in pollutant removal and greenhouse gas emissions.

scholarly journals Analisis Keberlanjutan Pengendalian Pencemaran Air Limbah Domestik Menggunakan Constructed Wetlands Teknik Surface Flow (SF)

2021 ◽  
Vol 17 (1) ◽  
pp. 13-24
Author(s):  
Iga Maliga ◽  
Chay Asdak ◽  
Efan Yudha Winata
Keyword(s):  
Constructed Wetlands ◽  
Quantitative Methods ◽  
Domestic Wastewater ◽  
Surface Flow ◽  
Social Dimension ◽  
Wastewater Management ◽  
Management Process ◽  
Economic Dimension ◽  
Qualitative And Quantitative Methods ◽  
River Contamination

Along with the significant increase of population in Bandung City at the moment, domestic wastewater management process must be considered to avoid river contamination, which one of the causes is domestic wastewater disposal without any prior management process. This study is located in Bandung City, which the research was performed in Research Center for Water Resources Office (PUSAIR) Bandung by involving residents of RW 09 Kelurahan Dago as respondents. The method used in this research is a combination of qualitative and quantitative methods. This study aims to analyze the sustainability of the domestic wastewater management process which is carried out using constructed wetlands by considering the economic, environmental, social, and technological aspects. The result shows that the sustainability value of the domestic wastewater management process conducted in the PUSAIR office is approximately 65.2% with the status of moderate sustainability. The detail result of each aspects is economic dimension 62.5%; ecological dimension 75%; social dimension 33.3%; and technological dimension 90%.Keywords: Domestic wastewater, Constructed wetlands, Surface flow techniques, Sustainability analysis

scholarly journals The Effects of Plants on Pollutant Removal, Clogging, and Bacterial Community Structure in Palm Mulch-Based Vertical Flow Constructed Wetlands

2019 ◽  
Vol 11 (3) ◽  
pp. 632 ◽  
Author(s):  
Marina Carrasco-Acosta ◽  
Pilar Garcia-Jimenez ◽  
José Alberto Herrera-Melián ◽  
Néstor Peñate-Castellano ◽  
Argimiro Rivero-Rosales
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Constructed Wetlands ◽  
Bacterial Community Structure ◽  
Rflp Analysis ◽  
Domestic Wastewater ◽  
Experimental Period ◽  
Pollutant Removal ◽  
Vertical Flow ◽  
Vertical Flow Constructed Wetlands

In this study, the effects of plants on the performance and bacterial community structure of palm mulch-based vertical flow constructed wetlands was studied. The wetlands were built in August 2013; one of them was planted with Canna indica and Xanthosoma sp., and the other one was not planted and used as a control. The experimental period started in September 2014 and finished in June 2015. The influent was domestic wastewater, and the average hydraulic surface loading was 208 L/m2d, and those of COD, BOD, and TSS were 77, 57, and 19 g/m2d, respectively. Although the bed without plants initially performed better, the first symptoms of clogging appeared in December 2014, and then, its performance started to fail. Afterwards, the wetland with plants provided better removals. The terminal restriction fragment length polymorphism (T-RFLP) analysis of Enterococci and Escherichia coli in the effluents suggests that a reduction in their biodiversity was caused by the presence of the plants. Thus, it can be concluded that the plants helped achieve better removals, delay clogging, and reduce Enterococci and E. coli biodiversity in the effluents.

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