Application of constructed wetlands for wastewater treatment in Nepal

2001 ◽  
Vol 44 (11-12) ◽  
pp. 381-386 ◽  
Author(s):  
R.R. Shrestha ◽  
R. Haberl ◽  
J. Laber ◽  
R. Manandhar ◽  
J. Mader
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Wastewater Treatment Plants ◽  
River System ◽  
Present Condition ◽  
Successful Implementation ◽  
Urban Centers ◽  
Untreated Wastewater ◽  
Under Construction

Surface water pollution is one of the serious environmental problems in urban centers in Nepal due to the discharge of untreated wastewater into the river-system, turning them into open sewers. Wastewater treatment plants are almost non-existent in the country except for a few in the Kathmandu Valley and even these are not functioning well. Successful implementation of a few constructed wetland systems within the past three years has attracted attention to this promising technology. A two-staged subsurface flow constructed wetland for hospital wastewater treatment and constructed wetlands for treatment of greywater and septage is now becoming a demonstration site of constructed wetland systems in Nepal. Beside these systems, five constructed wetlands have already been designed and some are under construction for the treatment of leachate and septage in Pokhara municipality, wastewater in Kathmandu University, two hospitals and a school. This paper discusses the present condition and treatment performance of constructed wetlands that are now in operation. Furthermore, the concept of the treatment wetlands under construction is also described here. With the present experience, several recommendations are pointed out for the promotion of this technology in the developing countries.

Evaluation of Small Wastewater Treatment Plants in the County of Århus – Denmark

1993 ◽  
Vol 28 (10) ◽  
pp. 33-41
Author(s):  
Jes la Cour Jansen ◽  
Bodil Mose Pedersen ◽  
Erik Moldt
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetlands ◽  
Biological Treatment ◽  
Wastewater Treatment Plants ◽  
Chemical Precipitation ◽  
Common Type ◽  
Treatment Efficiency ◽  
Effluent Quality ◽  
Different Types

Influent and effluent data from about 120 small wastewater treatment plants (100 - 2000 PE) have been collected and processed. Seven different types of plants are represented. The effluent quality and the treatment efficiency have been evaluated. The most common type of plant is mechanical/biological treatment plants. Some of them are nitrifying and some are also extended for chemical precipitation of phosphorus. Constructed wetlands and biological sandfilters are also represented among the small wastewater treatment plants.

scholarly journals Detection of untreated sewage discharges to watercourses using machine learning

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Peter Hammond ◽  
Michael Suttie ◽  
Vaughan T. Lewis ◽  
Ashley P. Smith ◽  
Andrew C. Singer
Keyword(s):  
Machine Learning ◽  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Training Data ◽  
Regulatory Oversight ◽  
Untreated Wastewater ◽  
Untreated Sewage ◽  
Water Companies ◽  
Analytical Approaches ◽  
Sewage Discharges

AbstractMonitoring and regulating discharges of wastewater pollution in water bodies in England is the duty of the Environment Agency. Identification and reporting of pollution events from wastewater treatment plants is the duty of operators. Nevertheless, in 2018, over 400 sewage pollution incidents in England were reported by the public. We present novel pollution event reporting methodologies to identify likely untreated sewage spills from wastewater treatment plants. Daily effluent flow patterns at two wastewater treatment plants were supplemented by operator-reported incidents of untreated sewage discharges. Using machine learning, known spill events served as training data. The probability of correctly classifying a randomly selected pair of ‘spill’ and ‘no-spill’ effluent patterns was above 96%. Of 7160 days without operator-reported spills, 926 were classified as involving a ‘spill’. The analysis also suggests that both wastewater treatment plants made non-compliant discharges of untreated sewage between 2009 and 2020. This proof-of-principle use of machine learning to detect untreated wastewater discharges can help water companies identify malfunctioning treatment plants and inform agencies of unsatisfactory regulatory oversight. Real-time, open access flow and alarm data and analytical approaches will empower professional and citizen scientific scrutiny of the frequency and impact of untreated wastewater discharges, particularly those unreported by operators.

scholarly journals Occurrence of SARS-CoV-2 RNA in Six Municipal Wastewater Treatment Plants at the Early Stage of COVID-19 Pandemic in The United States

Pathogens ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 798
Author(s):  
Samendra P. Sherchan ◽  
Shalina Shahin ◽  
Jeenal Patel ◽  
Lauren M. Ward ◽  
Sarmila Tandukar ◽  
...  
Keyword(s):  
United States ◽  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Quantitative Polymerase Chain Reaction ◽  
The United States ◽  
Secondary Effluent ◽  
Untreated Wastewater ◽  
Treatment Processes ◽  
Wastewater Samples

In this study, we investigated the occurrence of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) RNA in primary influent (n = 42), secondary effluent (n = 24) and tertiary treated effluent (n = 34) collected from six wastewater treatment plants (WWTPs A–F) in Virginia (WWTP A), Florida (WWTPs B, C, and D), and Georgia (WWTPs E and F) in the United States during April–July 2020. Of the 100 wastewater samples analyzed, eight (19%) untreated wastewater samples collected from the primary influents contained SARS-CoV-2 RNA as measured by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) assays. SARS-CoV-2 RNA were detected in influent wastewater samples collected from WWTP A (Virginia), WWTPs E and F (Georgia) and WWTP D (Florida). Secondary and tertiary effluent samples were not positive for SARS-CoV-2 RNA indicating the treatment processes in these WWTPs potentially removed SARS-CoV-2 RNA during the secondary and tertiary treatment processes. However, further studies are needed to understand the log removal values (LRVs) and transmission risks of SARS-CoV-2 RNA through analyzing wastewater samples from a wider range of WWTPs.

Enhancement of the performance of constructed wetlands for wastewater treatment in winter: the effect of Tubifex tubifex

RSC Advances ◽  
2016 ◽  
Vol 6 (41) ◽  
pp. 34841-34848 ◽  
Author(s):  
Yan Kang ◽  
Jian Zhang ◽  
Huijun Xie ◽  
Zizhang Guo ◽  
Pengfei Li ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Water Purification ◽  
Tubifex Tubifex ◽  
Batch Systems ◽  
Potential Use

An improved constructed wetland (CW) with the addition ofTubifex tubifexin winter was studied in laboratory batch systems. The outcomes of this study indicate that the potential use ofTubifex tubifexcould improve the ecosystem and water purification by CWs in winter.

scholarly journals Biological Activity of Wastewater Assessed Using in Vitro Cell-Based Assays

2021 ◽  
Author(s):  
Adamo R. Petosa ◽  
Monica Nowierski ◽  
Viviane Yargeau
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Estrogenic Activity ◽  
Solid Phase ◽  
Treated Wastewater ◽  
Chemical Analyses ◽  
Untreated Wastewater ◽  
17Β Estradiol ◽  
Receiving Waters

Abstract Bioanalytical tools, namely in vitro bioassays, can be employed in tandem with chemical analyses to assess the efficacy of wastewater treatment and the potential for adverse effects from the discharges of wastewater into receiving waters. In the present study, samples of untreated wastewater (i.e. influent) and treated wastewater (i.e. effluent) were collected from two wastewater treatment plants and a wastewater treatment lagoon serving municipalities in southern Ontario, Canada. In addition, grab samples of surface water were collected downstream of the lagoon discharge. After solid phase extraction (SPE) using ion-exchange columns for basic/neutral and acidic compounds, respectively, the extracts were analyzed for a suite of 16 indicator compounds. The two SPE extracts were combined for analysis of biological responses in four in vitro cell-based bioassays. The concentrations of several indicator compounds, including the estrogens, 17β-estradiol and 17α-ethinylestradiol, were below the limits of detection. However, androstenedione and estrone were detected in several influent samples. The concentrations of these steroid hormones and some of the other indicator compounds declined during treatment but acesulfame K, carbamazepine, trimethoprim and DEET persisted in the effluent. The MTS- CellTiter 96® AQueous One Solution Cell Proliferation Assay (MTS) indicated that cell viability was not affected by exposure to the extracts. The Qiagen Nuclear Receptors 10-Pathway Reporter Array indicated that several cellular pathways were upregulated, with the greatest upregulation observed with the estrogen receptor (i.e. induction ratios 12 to 47) and the liver X receptor (i.e. induction ratios 10 to 45). The ERα CALUX assay indicated that estrogenic activity was lower in effluents compared to influents, with the greatest estrogenic activity observed for grab samples of influent from the lagoon (i.e. 56-215 ng L-1 17β-estradiol equivalents). Finally, the results of the Nrf2 Luciferase Luminescence Assay indicated a lower oxidative stress in the effluent samples. Overall, the present study demonstrates that chemical analyses are limited in their ability to predict or explain reductions in the toxicity of treated wastewater. There are thus advantages to using a combination of chemical analyses and in vitro bioassays to monitor the treatment efficiency of wastewater treatment plants and to predict the potential impacts of wastewater discharges into receiving waters.

Constructed wetland for water quality improvement: a case study from Taiwan

2010 ◽  
Vol 62 (10) ◽  
pp. 2408-2418 ◽  
Author(s):  
C. Y. Wu ◽  
J. K. Liu ◽  
S. H. Cheng ◽  
D. E. Surampalli ◽  
C. W. Chen ◽  
...  
Keyword(s):  
Water Quality ◽  
Wastewater Treatment ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Water Reuse ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Nucleotide Sequence Analysis ◽  
Sediment Samples ◽  
Wetland System

In Taiwan, more than 20% of the major rivers are mildly to heavily polluted by domestic, industrial, and agricultural wastewaters due to the low percentage of sewers connected to wastewater treatment plants. Thus, constructed or engineered wetlands have been adopted as the major alternatives to clean up polluted rivers. Constructed wetlands are also applied as the tertiary wastewater treatment systems for the wastewater polishment to meet water reuse standards with lower operational costs. The studied Kaoping River Rail Bridge Constructed Wetland (KRRBCW) is the largest constructed wetland in Taiwan. It is a multi-function wetland and is used for polluted creek water purification and secondary wastewater polishment before it is discharged into the Kaoping River. Although constructed wetlands are feasible for contaminated water treatment, wetland sediments are usually the sinks for organics and metals. In this study, water and sediment samples were collected from the major wetland basins in KRRBCW. The investigation results show that more than 97% of total coliforms (TC), 55% of biochemical oxygen demand (BOD), and 30% of nutrients [e.g. total nitrogen (TN), total phosphorus (TP)] were removed via the constructed wetland system. However, results from the sediment analyses show that wetland sediments contained high concentrations of metals (e.g. Cu, Fe, Zn, Cr, and Mn), organic contents (sediment oxygen demand = 1.7 to 7.6 g O2/m2 d), and nutrients (up to 18.7 g/kg of TN and 1.22 g/kg of TN). Thus, sediments should be excavated periodically to prevent the release the pollutants into the wetland system and causing the deterioration of wetland water quality. Results of polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE), and nucleotide sequence analysis reveal that a variation in microbial diversity in the wetland systems was observed. Results from the DGGE analysis indicate that all sediment samples contained significant amounts of microbial ribospecies, which might contribute to the carbon degradation and nitrogen removal. Gradual disappearance of E. coli was also observed along the flow courses through natural attenuation mechanisms.

scholarly journals Preliminary Study of Sars-Cov-2 Occurrence in Wastewater in the Czech Republic

2020 ◽  
Vol 17 (15) ◽  
pp. 5508 ◽  
Author(s):  
Hana Mlejnkova ◽  
Katerina Sovova ◽  
Petra Vasickova ◽  
Vera Ocenaskova ◽  
Lucie Jasikova ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Wastewater Treatment ◽  
Czech Republic ◽  
Wastewater Treatment Plants ◽  
Chain Reaction ◽  
The Czech Republic ◽  
Untreated Wastewater ◽  
Preliminary Study ◽  
Polymerase Chain

The virus SARS-CoV-2, which has caused the recent COVID-19 pandemic, may be present in the stools of COVID-19 patients. Therefore, we aimed to detect SARS-CoV-2 in wastewater for surveillance of SARS-CoV-2 in the population. Samples of untreated wastewater were collected from 33 wastewater treatment plants (WWTPs) of different sizes within the Czech Republic. SARS-CoV-2 RNA was concentrated from wastewater and viral RNA was determined using real-time reverse transcription polymerase chain reaction (RT-qPCR). SARS-CoV-2 RNA was detected in 11.6% of samples and more than 27.3% of WWTPs; in some of them, SARS-CoV-2 was detected repeatedly. Our preliminary results indicate that an epidemiology approach that focuses on the determination of SARS-CoV-2 in wastewater could be suitable for SARS-CoV-2 surveillance in the population.

Design Recommendations for Subsurface Flow Constructed Wetlands for Nitrification and Denitrification

1999 ◽  
Vol 40 (3) ◽  
pp. 257-263 ◽  
Author(s):  
Christoph Platzer
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetlands ◽  
Wastewater Treatment Plants ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Oxygen Balance ◽  
Vertical Flow ◽  
Soil Aeration ◽  
Return Rates ◽  
Nitrification And Denitrification

The paper presents a design for nitrogen removal in subsurface flow wetlands. The nitrification in the vertical-flow beds (VFBs) is clearly determined by the oxygen balance in the filter. Full nitrification can only be achieved when the oxygen balance is positive. For sizing purposes equations for the calculation of oxygen demand and oxygen input are given. Three possibilities to achieve sufficient soil aeration are presented and explained. For the denitrification two possibilities are presented. From technical wastewater treatment plants predenitrification is well known. Return rates up to 200% can be used without hydraulic problems for the VFBs. In cases of low C/N ratios an additional application of HFBs has to be used. The design can be carried out using a design of 1 g NO3-N/m2,d achieving a 65% removal in more than 90% of the cases. The paper discusses some of the equations presented internationally. The suitability of the use of k-values for the processes nitrification and denitrification is especially questioned.

scholarly journals Potential of local plant Eleocharis dulcis for wastewater treatment in constructed wetlands system: review

2021 ◽  
Vol 896 (1) ◽  
pp. 012030
Author(s):  
L F Santosa ◽  
Sudarno ◽  
B Zaman
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Vital Role ◽  
Pollutant Loads ◽  
Local Plant ◽  
System Review ◽  
Eichornia Crassipes ◽  
Tidal Swamps ◽  
Phragmites Sp

Abstract Plants have a vital role in constructed wetlands because they provide oxygen in removing pollutants, as a medium of microorganisms, as absorbers of nutrients and other pollutants, must be resistant to high levels of pollutant loads and stressful conditions. Several plants have potential for constructed wetland, namely Phragmites sp., Typha sp., Canna indica, Colocasia esculenta, Eichornia crassipes, Eleocharis dulcis, and others. Eleocharis dulcis is a local plant commonly found in South Kalimantan. Eleocharis dulcis in the local, namely Purun tikus, grows in tidal swamps and grows in areas of high soil acidity (pH 2.5 – 3.5). Eleocharis dulcis can be used in tackling reclamation waste of acid sulfate soil which can absorb 1.45% of N elements; Cu 15 ppm; P 0.08%; Zn 48 ppm; Mg 0.16%; Fe 1.386 ppm; S 0.18%; Mn 923 ppm; K 2.05%; and Ca 0.22%. According to several studies that have been carried out, Eleocharis dulcis have been shown to reduce several pollutant loads such as Hg 99.84%; Pb; Cd; Fe 85.68%; SO4; Mn 78.94%; BOD 98.74%; COD 98.73%; and turbidity 80% also. The local plant Eleocharis dulcis can be potentially used as wastewater treatment, especially in a constructed wetland systems.

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