scholarly journals Quantifying the impact of runoff events on microbiological contaminant concentrations entering surface drinking source waters

2005 ◽  
Vol 3 (4) ◽  
pp. 453-468 ◽  
Author(s):  
R. S. Signor ◽  
D. J. Roser ◽  
N. J. Ashbolt ◽  
J. E. Ball
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Treatment Plant ◽  
Water Reservoir ◽  
Weighted Average ◽  
Health Concern ◽  
Quality Data ◽  
Parameter Estimates ◽  
The Impact ◽  
Runoff Events

Concentrations of microbiological contaminants in streams increase during rainfall-induced higher flow ‘event’ periods as compared to ‘baseflow’ conditions. If the stream feeds a drinking water reservoir, such periods of heightened pathogen loads may pose a challenge to the water treatment plant and subsequently a health concern to water consumers downstream. In order to manage this risk, it is desirable to first quantify the differences in surface water quality between baseflow and event conditions. The Event Mean Concentration (EMC) is a flow-weighted average concentration of a contaminant over the duration of a single event, proposed here as a standard parameter for quantifying the net effect of events on microbial water quality. Application of the EMC concept was assessed using flow and quality data for several events from an urbanised catchment. Expected mean EMCs were significantly larger than expected mean baseflow concentrations (p-value≤0.012) for three microbial agents - Escherichia coli (13,000 [n = 7] v. 610 [n = 16] mpn/100 ml), Cryptosporidium (234 [n = 6] v. 51 [n = 16] oocysts/10 litres) and Campylobacter (48 [n = 5] v. 2.1 [n = 16] mpn/100 ml). These parameter estimates were complemented by estimating data variability and uncertainty in the form of second-order random variables. As such the results are in a format appropriate for potential use as components in probabilistic risk assessments evaluating the effect runoff events have on drinking water quality.

Management of the Occoquan River basin: a 20-year case history

1995 ◽  
Vol 32 (5-6) ◽  
pp. 235-243 ◽  
Author(s):  
C. W. Randall ◽  
T. J. Grizzard
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Drinking Water ◽  
Wastewater Treatment ◽  
Water Supply ◽  
Land Use Changes ◽  
Treatment Plant ◽  
Water Reservoir ◽  
Land Use Management ◽  
Early Results

The high dam on the Occoquan River of Northern Virginia, United States of America, was constructed in 1957, forming a drinking water reservoir with a capacity of 37.1 × 106m3 formed by drainage from a 1 460 km2 watershed, and providing a safe yield of 189 251 m3 per day. Deteriorating water quality in the late 1960s led to a special “policy” for the watershed, designed to preserve the reservoir as a drinking water supply. Key provisions of the policy mandated replacement of the watershed's 11 publicly owned wastewater treatment works with a single advanced wastewater treatment plant (AWT), and establishment of the Occoquan Watershed Monitoring Programme. Early results from the programme established non-point nutrient pollution as a major cause of water quality deterioration and resulted in the implementation of non-point pollution controls throughout the watershed during the late 1970s. The AWT plant went on-line in July 1978. Continuous monitoring since 1973 has demonstrated both the necessity and the effectiveness of point and non-point nutrient controls for the preservation of the reservoir's water quality. The AWT plant provides excellent removal of organics and phosphorus, plus complete nitrification. The nitrates are discharged to the receiving stream to enhance conditions in the reservoir. Control policies include land-use management for the preservation of this essential water supply for 750 000 people in the Washington, D.C. suburbs. Land-use management decisions are based on the results obtained with a watershed-reservoir linked computer model which predicts water quality changes resulting from land-use changes.

An approach for determining the most critical among a suite of chemical contaminants at a drinking water intake

2013 ◽  
Vol 13 (3) ◽  
pp. 835-845
Author(s):  
Fei Chen ◽  
William B. Anderson ◽  
Peter M. Huck
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Intake ◽  
Treatment Plant ◽  
Quality Data ◽  
Exceedance Probability ◽  
Raw Water ◽  
Water Quality Data ◽  
Treatment Processes ◽  
Raw Water Quality

An integrated approach for the identification and assessment of the most critical chemical contaminant(s) at a drinking water intake has been developed. It involves the determination of a threshold or critical raw water concentration (CRWC) for target contaminants using the observed overall removal efficiency of a specific water treatment plant (WTP) and regulated drinking water concentrations for the target contaminants. The exceedance probability relative to the CRWC based on historical raw water quality monitoring data is then calculated. Finally, the integration of the raw water quality data and the overall efficiency of a particular WTP sequence allows for identification of the most critical contaminant(s) as well as an advance indication of which contaminants are most likely to challenge a plant. The proactive nature of this approach gives a utility the impetus and time to assess current treatment processes and potential alternatives. In addition, it was found that three- or four-parameter theoretical distributions are more appropriate than two-parameter probability distributions for the fitting of raw water quality data. This study reveals that the reliance on raw and/or treated water contaminant concentrations in isolation or on theoretical removals through treatment processes can, in some circumstances, be misguided.

scholarly journals Impact of Covid-19 Lockdown on Availability of Drinking Water in the Arsenic-Affected Ganges River Basin

2021 ◽  
Vol 18 (6) ◽  
pp. 2832
Author(s):  
Srimanti Duttagupta ◽  
Soumendra N. Bhanja ◽  
Avishek Dutta ◽  
Soumyajit Sarkar ◽  
Madhumita Chakraborty ◽  
...  
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
River Basin ◽  
Oxygen Demand ◽  
Water Sources ◽  
Quality Data ◽  
Ganges River ◽  
Drinking Water Sources ◽  
The Impact ◽  
Ganges River Basin

The 2020 COVID-19 pandemic has not only resulted in immense loss of human life, but it also rampaged across the global economy and socio-cultural structure. Worldwide, countries imposed stringent mass quarantine and lockdowns to curb the transmission of the pathogen. While the efficacy of such lockdown is debatable, several reports suggest that the reduced human activities provided an inadvertent benefit by briefly improving air and water quality. India observed a 68-days long, nation-wide, stringent lockdown between 24 March and 31 May 2020. Here, we delineate the impact of the lockdown on groundwater and river sourced drinking water sustainability in the arsenic polluted Ganges river basin of India, which is regarded as one of the largest and most polluted river basins in the world. Using groundwater arsenic measurements from drinking water wells and water quality data from river monitoring stations, we have studied ~700 km stretches of the middle and lower reaches of the As (arsenic)-polluted parts of the river for pre-lockdown (January–March 2020), syn-lockdown (April–May), and post-lockdown periods (June–July). We provide the extent of As pollution-free groundwater vis-à-vis river water and examine alleviation from lockdown as an opportunity for sustainable drinking water sources. The overall decrease of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) concentrations and increase of pH suggests a general improvement in Ganges water quality during the lockdown in contrast to pre-and-post lockdown periods, potentially caused by reduced effluent. We also demonstrate that land use (agricultural/industrial) and land cover (urban-periurban/rural) in the vicinity of the river reaches seems to have a strong influence on river pollutants. The observations provide a cautious optimistic scenario for potentially developing sustainable drinking water sources in the arsenic-affected Ganges river basin in the future by using these observations as the basis of proper scientifically prudent, spatially adaptive strategies, and technological interventions.

scholarly journals Assessment of rainwater harvesting and maintenance practice for better drinking water quality in rural areas

2021 ◽  
Author(s):  
Dung A. Dao ◽  
Son H. Tran ◽  
Huyen T. T. Dang ◽  
Viet-Anh Nguyen ◽  
Viet Anh Nguyen ◽  
...  
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Rural Areas ◽  
Rainwater Harvesting ◽  
Water System ◽  
Water Reservoir ◽  
Drinking Water Quality ◽  
P Value ◽  
Operation And Maintenance ◽  
The Impact

Abstract In many areas of the world, rainwater has been collected and consumed by people. Our research aims to assess the use of rainwater and the impact of operation and maintenance activities of the rainwater system on drinking water quality in rural areas where there is no access to a public drinking water system. Through the questionnaire, direct visits, interviews and sampling of water at surveyed households (HHs), it was found that 100 and 98% of surveyed HHs used rainwater for drinking and cooking, respectively. Nearly, 80% of them were aware of the necessity of frequent reservoir cleaning as well as first-flush removal. Cleaning the water reservoir had a significant impact on water quality, in particular the total dissolved solids (p-value < 0.05). The use of strainers and more frequency of cleaning the catchment roofs and gutters would make the lower turbidity in water. However, the use of strainers would reduce the dissolution of oxygen in the reservoirs. A recommendation on the frequency of maintaining the rainwater harvesting systems was proposed after assessment of the operation and maintenance behaviors at surveyed HHs.

Pollution by phosphorus and nitrogen in water streams feeding the Zelivka drinking water reservoir

1999 ◽  
Vol 39 (12) ◽  
pp. 207-214 ◽  
Author(s):  
Jiri Holas ◽  
Marketa Holas ◽  
Vladimir Chour
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Bottom Sediments ◽  
Arable Land ◽  
Treatment Plant ◽  
Water Reservoir ◽  
Phosphorus Release ◽  
Phosphorus Compounds ◽  
Reservoir Water ◽  
Drinking Water Reservoir

This case study refers to long term monitoring of Martinicky and Sedlický Brooks, which represent general water-quality characteristics well related to the watershed of the whole Zelivka drinking water reservoir. For a period of more than ten years water-quality indices were systematically monitored at each profile together with actual discharges recorded at selected profiles. It is seen that the only critical pollutants are nutrients, namely nitrate nitrogen and total phosphorus, originating from both urban and agricultural sources, while industrial pollution is relatively marginal in the watershed. Phosphorus concentrations do not display any simple time regularity. Persistent all-year background phosphorus load gives evidence of the urban origin of pollution. Total input of phosphorus into the reservoir came mainly from surface inflows, out of rainfall and out of bottom sediments. Phosphorus was found to be the limiting nutrient for phytoplankton growth and was therefore recognised as the principal element responsible for reservoir eutrophication rates, which could probably be effectively controlled by concerted abatement actions. Most of the watershed born nitrogen pollution has a distinctly non-point (diffuse) character. Typical yearly pattern of nitrate concentrations means distinct and regular increase during end-of-winter and spring period due to processes of mineralization, typical for productive arable land on soils with good drainage properties. The process of state economy transition, which was initiated in 1989, has led to dramatic decrease of fertiliser inputs per hectare of land. Reduced fertilisation of arable land has not yet been reflected in improved quality of surface waters. The proposed strategy for prevention and abatement in the Zelivka reservoir eutrophication should be based on win-win principles applied throughout the entire watershed and, at present, preferentially focused on:phosphorus cycle control and improvement within both the watershed and reservoir water (diminished use of chemicals producing reactive phosphorus compounds, improved phosphorus removal from urban waste water, to prevent phosphorus release from bottom sediments)general soil erosion control and prevention - grassland cultivation on vulnerable areas and buffer zones and subsidy for cultivating plants on arable land even between growing periodsproper maintenance and improvement of treatment plant technology to maintain actual standards of produced drinking water.

scholarly journals Organisational arrangements and drinking water quality

2010 ◽  
Vol 10 (2) ◽  
pp. 227-241 ◽  
Author(s):  
J. O. Jenkins
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Quality Parameters ◽  
Drinking Water Quality ◽  
Quality Data ◽  
England And Wales ◽  
Republic Of Ireland ◽  
Problematic Drinking ◽  
The Republic ◽  
The Impact

This paper discusses the findings of a research project which explored the impact of varying organisational arrangements on drinking water quality in England and Wales, and the Republic of Ireland. It is established that drinking water quality has been of a consistently higher standard in England and Wales in comparison with the Republic of Ireland. It is also demonstrated that the associated organisational arrangements in England and Wales have been more successful in tackling certain problematic drinking water quality parameters. The paper concludes by arguing that national governments, and their regulatory agencies, should view the rationalisation of organisations involved in the provision of drinking water as key to ensuring better drinking water quality. It is also suggested that state regulators who are responsible for ensuring the quality of drinking water end their dependency on water providers for quality data. They should instead become capable of directly monitoring drinking water quality via their own sampling regime. It is argued that this organisational arrangement would be representative of a more progressive and robust organisational approach to ensuring the supply of safe high quality drinking water.

scholarly journals Increasing of drinking water quality at real water treatment plant by recarbonization process

2012 ◽  
Vol 5 (1) ◽  
pp. 75-79 ◽  
Author(s):  
Anna Luptáková ◽  
Karol Munka ◽  
Ján Derco
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Drinking Water Quality ◽  
World Health ◽  
Surface Source ◽  
The Impact

Increasing of drinking water quality at real water treatment plant by recarbonization process According to the World Health Organization, chemical and microbial contaminants in drinking water will continue in the interest of suppliers of drinking water. The review establishment of new knowledge for drinking water including the potential benefits of the mineral content is necessary. The paper is focused on an assessment of the quality of water from surface source for drinking water preparation and quality of drinking water produced at the real plant. The lab-scale verification of water recarbonization with lime and carbon dioxide was chosen based on the results of full scale plant data analysis. Recarbonization tests were carried out with the raw water and the impact of recarbonization on coagulation process at different coagulant doses was studied. The results show that water recarbonization had adverse influence on the water treatment processes.

The Impact of Missing and Error-Prone Auxiliary Information on Sparse-Matrix Sub-Population Parameter Estimates

Methodology ◽  
2015 ◽  
Vol 11 (3) ◽  
pp. 89-99 ◽  
Author(s):  
Leslie Rutkowski ◽  
Yan Zhou
Keyword(s):  
Sparse Matrix ◽  
Small Body ◽  
Auxiliary Information ◽  
Poor Quality ◽  
Quality Data ◽  
Estimation Methods ◽  
Parameter Estimates ◽  
Population Parameter ◽  
Conditioning Model ◽  
The Impact

Abstract. Given a consistent interest in comparing achievement across sub-populations in international assessments such as TIMSS, PIRLS, and PISA, it is critical that sub-population achievement is estimated reliably and with sufficient precision. As such, we systematically examine the limitations to current estimation methods used by these programs. Using a simulation study along with empirical results from the 2007 cycle of TIMSS, we show that a combination of missing and misclassified data in the conditioning model induces biases in sub-population achievement estimates, the magnitude and degree to which can be readily explained by data quality. Importantly, estimated biases in sub-population achievement are limited to the conditioning variable with poor-quality data while other sub-population achievement estimates are unaffected. Findings are generally in line with theory on missing and error-prone covariates. The current research adds to a small body of literature that has noted some of the limitations to sub-population estimation.

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