scholarly journals Effect of lockdown on wastewater characteristics: a comparison of two large urban areas

2020 ◽  
Vol 82 (12) ◽  
pp. 2813-2822
Author(s):  
Marie-Noëlle Pons ◽  
Pauline Louis ◽  
Davide Vignati
Keyword(s):  
Urban Area ◽  
Urban Areas ◽  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Carbon Sources ◽  
Oxygen Demand ◽  
Total Suspended Solids ◽  
Noticeable Effect ◽  
Kjeldahl Nitrogen

Abstract The effect of the lockdown imposed to limit the spread of SARS-CoV-2 in France between March 14 and May 11, 2020 on the wastewater characteristics of two large urban areas (with between 250,000 and 300,000 inhabitants) was studied. The number of outward and inward daily commuters was extracted from national census databases related to the population and their commuting habits. For urban area A, with the larger number of daily inward commuters (110,000, compared to 53,000 for B), lockdown was observed to have an effect on the monthly load averages of chemical oxygen demand, biochemical oxygen demand, total Kjeldahl nitrogen, total suspended solids and total phosphorus, all of which decreased (confidence level of 95%). This decrease, which varied between 20% and 40% and reached 45% for COD, can be related to the cessation of catering and activities such as hairdressing, which generate large amounts of graywater. The ammonium loads, due to the use of toilets before leaving for work and after returning from work, remained constant. In the case of urban area B, lockdown had no noticeable effect. More data would be necessary in the long term to analyze the effect of changes in the balance between ammonia and carbon sources on the operation of wastewater treatment plants.

scholarly journals Multi-Scale Analysis of the Dependence of Water Quality on Land Use Using Linear and Mixed Models

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2618
Author(s):  
Johann Alexander Vera Mercado ◽  
Bernard Engel
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Suspended Solids ◽  
Spatial Scales ◽  
Oxygen Demand ◽  
Total Suspended Solids ◽  
Quality Parameters ◽  
Total Kjeldahl Nitrogen ◽  
Nitrate And Nitrite ◽  
Kjeldahl Nitrogen

Land use influences water quality in streams at different spatial scales and varies in time and space. Water quality has long been associated with agricultural and urban land uses in catchments. The effects of developed, forest, pasture, and agricultural land use on nitrogen, nitrate, and nitrite (NNN); total phosphorus (TP); total suspended solids (TSS); chemical oxygen demand (COD); dissolved oxygen (DO) and total Kjeldahl nitrogen (TKN) concentrations and their sensitivity were quantified to spatial pattern differences. The linear mixed modeling framework was used to examine the importance of spatial extent on models with water quality parameters as the response variable and land use types as the predictor variable. The results indicated that land use categories on different water quality parameters were significant and dependent on the selected spatial scales. Land use exhibited a strong association with total phosphorus and total suspended solids for close reach distances. Phosphorus is not highly soluble, and it binds strongly to fine soil particles, which are transported by water via runoff. Nitrogen, nitrate, and nitrite, dissolved oxygen, chemical oxygen demand, and total Kjeldahl nitrogen concentrations were better predicted for further reach distances, such as 45 or 50 km, where the best model of nitrogen, nitrate, and nitrite is consistent with the high mobility of NO3−.

Aeration and Water Hyacinths in Waste Stabilization Ponds

1987 ◽  
Vol 19 (12) ◽  
pp. 265-271
Author(s):  
P. R. Thomas ◽  
H. O. Phelps
Keyword(s):  
Biochemical Oxygen Demand ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Total Suspended Solids ◽  
Substantial Improvement ◽  
Additional Treatment ◽  
Coliform Bacteria ◽  
Effluent Quality ◽  
Stabilization Ponds ◽  
Water Hyacinths

The investigation was based on two facultative stabilization ponds initially designed to operate in parallel, and now receive wastewater in excess of their capacities from a fast expanding housing estate in the Caribbean Island of Trinidad. Because of the deterioration of the effluent quality relative to acceptable standards, an attempt was made to upgrade the ponds using water hyacinths at the early stages. However, from the results, it was clear that the introduction of water hyacinths in the test pond did not lead to any substantial improvement in the effluent because of the high loading on the pond. Therefore the ponds were modified to operate in series with surface aerators installed in the first pond. Initially, the effluent quality was monitored in terms of total suspended solids, volatile suspended solids, biochemical oxygen demand, faecal coliform bacteria, pH and dissolved oxygen with aeration in the first pond and no aquatic plants in the second pond. Although there was a significant improvement in the effluent quality, the values remained above the standards. As a result, water hyacinths were introduced in the second pond and the effluent quality monitored together with aeration in the first pond. The effluent quality improved with total suspended solids and biochemical oxygen demand values both as low as 10 mg/l in certain months, but additional treatment was needed to reduce faecal conforms.

scholarly journals DECOLOURIZATION OF TRIPHENYLMETHANE DYES AND DYE INDUSTRY EFFLUENT BY STAPHYLOCOCCUS AUREUS ISOLATED FROM DYE CONTAMINATED SITE

2016 ◽  
Vol 8 (9) ◽  
pp. 258 ◽  
Author(s):  
R. Sandhiya ◽  
K. Sumaiya Begum ◽  
D. Charumathi
Keyword(s):  
Staphylococcus Aureus ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Total Suspended Solids ◽  
Dye Decolorization ◽  
Total Dissolved Solids ◽  
Biological Oxygen Demand ◽  
Dyeing Wastewater ◽  
Triphenylmethane Dyes ◽  
Dissolved Solids

<p><strong>Objective: </strong>The objectives of the present study were a) to isolate and screen bacteria for dye removal from synthetic solution b) to optimize various variables such as pH, static/shaking and initial dye concentration on degradation of triphenyl methane dyes namely basic violet 3 and basic green 4 by isolated <em>Staphylococcus aureus</em> c) to analyse enzymes involved in the biodegradation of triphenylmethane dyes d) to treat real leather dyeing wastewater with newly isolated strain of <em>Staphylococcus aureus </em>e) to characterize untreated and treated leather dyeing wastewater f) to study the effects of real and treated effluent on plants and <em>Rhizobium</em>.<strong></strong></p><p><strong>Methods: </strong>Isolation of bacteria from sludge was carried out by spread plate method and the bacteria was identified by morphological and biochemical characterization. The isolated bacterium was screened for dye decolorization potential of triphenylmethane dyes basic violet 3 and basic green 4 The effects of parameters were studied by varying pH (from 3 to 9), temperature (from 15-45 °C), and initial dye concentration (from 10-500 mg/l). The enzyme involved in biodegradation was studied in intracellular extract. Real leather dyeing wastewater was treated with the bacteria and characterized. The treated wastewater was tested on plants and <em>Rhizobium </em>for toxicity. <strong></strong></p><p><strong>Results: </strong>Dye decolorization potential of bacteria <em>Staphylococcus aureus</em> isolated from wastewater for leather dyes basic violet 3 and basic green 4 were evaluated. Dye decolorization using bacteria was found to be dependent on physicochemical parameters (shaking, pH and initial dye concentration). Enzymes NADH-DCIP reductase and MG reductase were found to play dominant role during biodegradation of synthetic dyes. Application oriented studies using growing bacteria in pure cultures were carried out with leather dyeing wastewater collected from DKS prime tanners. Analysis of raw leather dyeing wastewater showed high pollution load in terms of color, Total solids, Total suspended solids, Total dissolved solids and Biological oxygen demand whereas the leather dyeing wastewater treated with pure culture of <em>Staphylococcus aureus</em> showed considerable decrease in Total solids, Total suspended solids, Total dissolved solids and Biological oxygen demand values which were within the permissible limits. Phytotoxicity and microbial toxicity studies confirmed the non-toxic nature of treated leather dyeing wastewater. <strong></strong></p><p><strong>Conclusion: </strong>Our study proved that <em>Staphylococcus aureus</em> can serve as a potential remediation agent for the treatment of leather dyeing wastewater.</p>

scholarly journals Shewhart's control charts and process capability ratio applied to a sewage treatment station

2014 ◽  
Vol 34 (4) ◽  
pp. 770-779 ◽  
Author(s):  
Fábio Orssatto ◽  
Marcio A. Vilas Boas ◽  
Ricardo Nagamine ◽  
Miguel A. Uribe-Opazo
Keyword(s):  
Control Charts ◽  
Suspended Solids ◽  
Sewage Treatment ◽  
Oxygen Demand ◽  
Process Capability ◽  
Total Suspended Solids ◽  
Statistical Control ◽  
Environmental Legislation ◽  
Shewhart Control Charts ◽  
Shewhart Control

The current study used statistical methods of quality control to evaluate the performance of a sewage treatment station. The concerned station is located in Cascavel city, Paraná State. The evaluated parameters were hydrogenionic potential, settleable solids, total suspended solids, chemical oxygen demand and biochemical oxygen demand in five days. Statistical analysis was performed through Shewhart control charts and process capability ratio. According to Shewhart charts, only the BOD(5.20) variable was under statistical control. Through capability ratios, we observed that except for pH the sewage treatment station is not capable to produce effluents under characteristics that fulfill specifications or standard launching required by environmental legislation.

scholarly journals Water Woes in Zimbabwe’s Urban Areas in the Middist Of Plenty: 2000 -Present

2012 ◽  
Vol 1 (2) ◽  
pp. 151 ◽  
Author(s):  
Enock C. Makwara
Keyword(s):  
Waste Management ◽  
Water Supply ◽  
Urban Area ◽  
Urban Areas ◽  
Service Failure ◽  
Urban Residents ◽  
Contaminated Water ◽  
Recent Outbreak

Zimbabwe’s urban areas are choking under the weight of over-crowdedness amidstdilapidated infrastructure that is characterised by constant service failure. The water andsewer systems of the country’s major urban centres are on the verge of collapse, thusputting millions of people in danger of consuming contaminated water, including thatfrom underground sources. Waste management and water supply problems manifestthemselves as challenges bedevilling many an urban area in the country. The quality andquantity of water supplied in Zimbabwe’s urban centres has plummeted in recent yearsand has assumed crisis proportions owing to the difficult economic situation and otherchallenges faced by the country. The situation is desperate and dire, as is evidenced by thepoor quality of delivered water, severe water rationing and the outbreak of water-bornediseases in the urban areas dotted across the country. The situation demands and dictatesthat solutions be proffered as a matter of urgency.The recent outbreak of epidemics hasbeen blamed on lack of access to safe water and poor sanitation, two crucial factors incontrolling the spread of diseases. An overly bureaucratic environment, where decisionsand processes take longer, makes life complicated for poor urban residents. Such ascenario motivated the researchers to examine the problem with a view to suggest waysand means of intervening to mitigate and resolve the problem. It emerged from thefindings that the problem is multifaceted in nature, hence a whole range of measures needto be adopted if a long-term solution is to be provided.

scholarly journals URBAN GROWTH AND WATER QUALITY IN THIMPHU, BHUTAN

2013 ◽  
pp. 82-95 ◽  
Author(s):  
Nandu Giri ◽  
O. P. Singh
Keyword(s):  
Water Quality ◽  
Urban Area ◽  
Water Samples ◽  
Urban Areas ◽  
Forest Cover ◽  
Rapid Development ◽  
Oxygen Demand ◽  
Capital City ◽  
Quality Data ◽  
Water Quality Data

Detailed study was undertaken in 2008 and 2009 on assessment of water quality of River Wang Chhu which flows through Thimphu urban area, the capital city of Bhutan. The water samples were examined at upstream of urban area, within the urban area and its downstream. The water samples were analyzed by studying the physico-chemical, biological and benthic macro-invertebrates. The water quality data obtained during present study are discussed in relation to land use/land cover changes(LULC) and various ongoing human activities at upstream, within the each activity areas and it’s downstream. Analyses of satellite imagery of 1990 and 2008 using GIS revealed that over a period of eighteen years the forest, scrub and agricultural areas have decreased whereas urban area and road network have increased considerably. The forest cover, agriculture area and scrub decreased from 43.3% to 42.57%, 6.88% to 5.33% and 42.55% to 29.42%, respectively. The LULC changes effect water quality in many ways. The water temperature, pH, conductivity, total dissolved solids, turbidity, nitrate, phosphate, chloride, total coliform, and biological oxygen demand were lower at upstream and higher in urban area. On the other hand dissolved oxygen was found higher at upstream and lower in urban area. The pollution sensitive benthic macro-invertebrates population were dominant at upstream sampling sites whereas pollution tolerant benthic macro-invertebrates were found abundant in urban area and its immediate downstream. The rapid development of urban infrastructure in Thimphu city may be posing serious threats to water regime in terms of its quality. Though the deterioration of water quality is restricted to a few localized areas, the trend is serious and needs proper attention of policy planners and decision makers. Proper treatment of effluents from urban areas is urgently needed to reduce water pollution in such affected areas to check further deterioration of water quality. This present study which is based on upstream, within urban area and downstream of Thimphu city can be considered as an eye opener.

scholarly journals Wastewater treatment in flow photobioreactors continuous illuminated by artificial and solar light

2020 ◽  
Vol 9 (6) ◽  
pp. e183963748
Author(s):  
Rafael Souza Leopoldino Nascimento ◽  
Ludymyla Marcelle Lima Silva ◽  
Lucas Periard ◽  
Anibal da Fonseca Santiago
Keyword(s):  
Organic Matter ◽  
Wastewater Treatment ◽  
Chemical Oxygen Demand ◽  
Continuous Flow ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Total Suspended Solids ◽  
Operational Stability ◽  
Artificial Light ◽  
Light Emitting

The technology of microalgae photobioreactors and illuminated by LEDs has been widely studied for the treatment of wastewater. However, sunlight is a free resource and should be taken advantage of. But the question remains whether photobioreactors illuminated by natural (sunlight) light in combination with artificial light can have greater operational stability or greater performance when compared to systems illuminated only by artificial light. In this context, continuous flow photobioreactors illuminated by Light Emitting Diodes (LEDs) combined, or not, with sunlight were operated and had their performance evaluated. The variables analyzed were pH, OD, chemical oxygen demand (COD), chlorophyll - a and total suspended solids. The photobioreactors were effective for removing organic matter, with 75 ± 15% in the photobioreactor illuminated by LED and 65 ± 10% in the photobioreactor illuminated by sunlight and LED. The results showed that the use of combined lighting favors the production of dissolved oxygen and ensures greater operational stability in the removal of carbonaceous organic matter.

Uncertainties of spectral in situ measurements in wastewater using different calibration approaches

2006 ◽  
Vol 53 (12) ◽  
pp. 187-197 ◽  
Author(s):  
L. Rieger ◽  
G. Langergraber ◽  
H. Siegrist
Keyword(s):  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Total Suspended Solids ◽  
Data Sets ◽  
Global Calibration ◽  
Nitrite Nitrogen ◽  
Calibration Methods ◽  
Using Data ◽  
Nitrate And Nitrite

Three calibration methods were applied to UV/VIS spectra recorded in the influent of six wastewater treatment plants (WWTPs) to measure total COD (CODtot), filtered COD (CODfil), nitrate and nitrite nitrogen (NOx-N) and total suspended solids (TSS). It could be shown that a calibration of the sensor using data sets from four Swiss WWTPs leads to an improvement of the precision in comparison to the global calibration provided by the manufacturer. A calibration to the specific wastewater matrix always improves the results and gives the highest accuracy. For CODtot a mean coefficient of variation CVx of 12.5% could be reached, whereas for NOx-N only weak results were achieved (average CVx=36%).

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