Nanofiltration: improvements of water quality in a large distribution system

2003 ◽  
Vol 3 (1-2) ◽  
pp. 193-200 ◽  
Author(s):  
S. Peltier ◽  
M. Cotte ◽  
D. Gatel ◽  
L. Herremans ◽  
J. Cavard

A nanofiltration (NF) treatment was introduced during the autumn of 1999 in the Méry-sur-Oise treatment plant which feeds the northern Parisian suburbs distribution system. A study was conducted over 4 years to compare the water quality before and after nanofiltration. The results confirmed that NF treatment produced a low DOC concentration in water (average 0.7 mg C/L). This reduction of DOC concentration levels enabled an improved stability of chlorine residual that has been reduced to 0.2 mg/L at the outlet of the plant. The formation of trihalomethanes was thus reduced by 50% in the network. Moreover, the reduction of BDOC enabled an improved biological stability in the water and enhanced the microbiological water quality during distribution. In addition, the NF treatment enhanced the physico-chemical water quality.

2018 ◽  
Vol 6 (2) ◽  
pp. 12
Author(s):  
Dipitseng Manamela ◽  
Omotayo Awofolu

This article investigates the impact of anthropogenic activities on an important surface water from physico-chemical, chemical and microbial perspectives. The surface water, referred to as Blesbokspruit is in the West Rand District of South Africa. Potential impactors include wastewater treatment plant, mines, farmlands and informal settlements. Water samples were collected from nine purposively selected sampling points and analysed in 2014. The mean values of analysed variables across sampling sites and periods ranged from pH: 7.4-8.4; EC: 93.0 - 146.6 mS/m; TSS: 11.3 – 39.0 mg/L; TDS: 590.3 - 1020.3 mg/L; COD: 15.6- 34.8 mg/L. Those for anions varied from NO3-: 0.2- 2.1 (mg/L) N; PO43- : 0.4-0.9 mg/L and SO42-: 118.6 - 379.5 mg/L. The metallic variables ranged from As: 0.01-0.06 mg/L; Cd: 0.02-0.06 mg/L; Fe: 0.04-0.73 mg/L; Cu: 0.02 – 0.05 mg/L and Zn: 0.05 – 0.15 mg/L. The Faecal coliform varied from 15.9-16878.5 cfu/100 ml; Total coliform: 92.9-430294 cfu/100 ml and HPC from 4322.5-39776 cfu/1ml. Detection of toxic metals and pathogenic organisms above target safety limits indicate unsuitability of the water for domestic use with impact on the health of aquatic ecosystem. The study generally revealed the impact of anthropogenic activities on the surface water quality.


Author(s):  
Sarma Nandini ◽  
Pedro Ramirez García ◽  
S.S.S. Sarma

<p>Lake Xochimilco is a eutrophic water body in Mexico City used by the local population for aquaculture and agriculture. Water level is maintained with inputs of partially treated waste water from the Cerro de la Estrella treatment plant. In this study we analysed the water quality at two sites of Lake Xochimilco, Lake Xaltocan and the Santa Cruz Canal using various indicators such as zooplankton diversity, saprobic indices, bacterial concentrations and physico-chemical variables. Eighty litres of water was filtered from Lake Xochimilco from each site, once a month from March to October of 2012, and the rotifers, cladocerans and copepods were enumerated and identified. Physico-chemical parameters such as temperature, pH, Secchi depth, water depth, nitrogen and phosphorus and chlorophyll a concentrations, and bacterial densities were measured. During the study we recorded 33 species of rotifers, the most abundant being <em>Brachionus angularis</em>, <em>B. calyciflorus</em> and <em>B. havanaensis</em>.  Among the microcrustaceans the most abundant were the cladoceran <em>Moina micrura</em> and the copepods <em>Acanthocyclops americanus</em> and <em>Arctodiaptomus dorsalis</em>. The species diversity was around 2 bits/ind. and the saprobic index between 1.5-2.0, indicating that both sites were β meso-saprobic.  At both sites nitrogen was &lt;1 mg/L and phosphorus ranged between 2.5-7.8 mg/L. Chlorophyll a concentrations were between 66-136 µg/L. The toxigenic (<em>Vibrio cholerae </em>No-O1/No-O139) and the non-toxigenic (<em>Vibrio cholerae </em>No-O135) strains of the bacterium were recorded, closely associated with littoral rotifers and cladocerans particularly <em>Brachionus quadridentatus</em> and  <em>Alona</em> sp. All variables indicate that these sites in Lake Xochimilco are eutrophic and highly contaminated and that the water quality needs to be improved.<strong></strong></p>


2018 ◽  
Vol 59 ◽  
pp. 00005
Author(s):  
Barbara Tchórzewska-Cieślak ◽  
Dorota Papciak ◽  
Katarzyna Pietrucha-Urbanik ◽  
Andżelika Pietrzyk

The subject of the work is the analysis and assessment of the risk of biological instability of water. The lack of water stability causes the increased susceptibility of the distribution system to secondary microbial contamination of water and constitutes a hazard for consumers’ health. The risk is expressed as the loss of water supply safety and distinguishes a failure of not meeting certain water quality parameters that can influence physico-chemical parameters and the bacteriological quality of the water supplied to the consumers. In the paper the method of analysing and evaluating the risk of loss of biostability of tap water is presented. The presented analysis was performed on the basis of the operating data from the water treatment plant.


1992 ◽  
pp. 1-9
Author(s):  
Ir. Abd. Rasid Othman Othman ◽  
Mohd Asri Mohd Nor ◽  
Azmi Aris ◽  
Teng Keat Hui ◽  
Jagjit Singh Jora Singh

In a assessment of drinking water quality in Skudai Johor Bahru, piped water samples in the distribution system from three different standpipe locations in Taman Sri Skudai, Taman Sri Pulai and Universiti Teknologi Malaysia (UTM) campus were collected and tested for selected ions and bacteriological quality. The result show that pipe water supplied from a treatment plant at Gunung Pulai in Pontian was low in mineral content. No Eschericia Coli were detected expected at the UTM Campus with concentration of 3 counts/100 mL in one out of 12 sample tested. Total coliforms were found at each site with concentration ranging from 1 to 13 counts/100 mL in 15 out of 6 samples. Except for the coliforms and the fluoride levels exceeding a little over 1.5 mg/L in 8% of the samples, drinking water in the distribution system in the study area can generally be said to have met the World Health Organization (WHO) guidelines during the study period. However, with the detection of coliforms and E. Coli at the household standpipes, the possibility of the distribution system in Skudai having pathogen contamination from time to time cannot be dismissed. Keywords: drinking water quality


2018 ◽  
Vol 10 (11) ◽  
pp. 1061-1082
Author(s):  
Abayomi Tolulope Oyewale ◽  
Taiwo Adekanmi Adesakin ◽  
Olaoluwa Oyedeji ◽  
Adedeji Idowu Aduwo ◽  
Mufutau Kolawole Bakare

2020 ◽  
Vol 32 (3) ◽  
Author(s):  
Tanje Un Jenat ◽  
Md. Tariqul Islam ◽  
Md. Jahir Bin Alam

In this paper, an attempt has been taken to assess the water quality and its impact on local inhabitants along with their health problems due to industrialization without treatment plant in Noapara and Chhatiain Union of Habiganj. To assess the water quality, physico-chemical analysis of water was carried out based on their importance in different usage. Water samples of different locations have DO in the ranges of 2.1mg/l to 9.8mg/l. According to WQI, during dry period, about 42% water samples are ranked as “Unsuitable” whereas 28.5% as “Excellent” during monsoon.CDI value from dermal absorption was evaluated using USEPA guidelines and found the highest amount as 140mg and 150mg for children and adult respectively for only elements related with nitrate and ammonia.


2004 ◽  
Vol 4 (4) ◽  
pp. 235-243 ◽  
Author(s):  
I. Fisher ◽  
G. Kastl ◽  
A. Sathasivan ◽  
P. Chen ◽  
J. van Leeuwen ◽  
...  

Water treatment processes produce water with low turbidity and colour. It is also now becoming necessary to reduce DOC (Dissolved Organic Carbon) so that less chlorine is lost in a distribution system and less THMs (trihalomethanes) are formed. Enhanced coagulation (exceeding other requirements) at pH of about 5-6 is known to significantly reduce DOC so that acceptable water quality can be achieved at the tap. In this paper, models are integrated to project the impact of water treatment on water quality through the entire distribution system. A DOC removal model, which predicts DOC resulting from a given coagulant, its dose and the coagulation pH, is used to simulate the treatment. By linking this model of DOC removal with models of chlorine decay and THM formation, the impact of treatment on chlorine and THM concentrations in a distribution system can be simulated. This method was applied in a case study with relatively high initial DOC. It was shown that more DOC can be removed by using ferric coagulant than the current practice achieves. This would result in an improved chlorine profile and a substantial reduction in THM concentrations.


2005 ◽  
Vol 5 ◽  
pp. 113-142 ◽  
Author(s):  
M. W. Lechevallier ◽  
W. C. Becker ◽  
P. Schorr ◽  
R. G. Lee

Biological treatment was examined for production of biologically stable water, increase disinfectant stability, and reduced formation of disinfection by products. Monitoring of assimilable organic carbon (AOC) levels in the effluent of the Swimming River Treatment Plant (SRTP) showed that values >100 µg/L could be related to the occurrence of coliform bacteria in the distribution system. A treatment goal of <100 µg/L was established for biologically active treatment processes. Granular activated carbon (GAC) filters were found to support a larger bacterial population, and thus, provide better biological removal of AOC and total organic carton (TOC). All biologically active filters showed good performance relative to effluent turbidity levels, and headloss development. Preozonation of raw water increased AOC levels an average of 2.3 fold, and always increased filter effluent AOC levels relative to nonozonated water. Application of free chlorine to GAC filters did not inhibit biological activity. Application of chloramines to GAC filters showed a slight inhibitory affect relative to free chlorine. Effluent AOC levels averaged 82 µg/L at an EBCT of 5 min, and decreased to an average of 57 µg/L at 20 min EBCT. EBCT did affect TOC removals, with efficiencies averaging 29, 33, 42, and 51 % removal at EBCTs of 5, 10, 15 and 20 min, respectively. Trihalomethane formation potentials (THMFP) were related to TOC levels. Processes Chat decreased TOC levels also decreased THMFP. A preozonated GAC/sand filter (EBCT 10 min) achieved an annual average 54 % removal of THMFP precursors. Post disinfection of biologically treated effluents reduced HPC bacterial counts by 2-2.5log10. Post chlorination or chloramination of prechlorinated GAC/sand effluents resulted in a 20 %, or a 44 % (respectively) increase in AOC levels. Post disinfection of preozonated water resulted in small (<8%) AOC increases. Despite increases in AOC levels, prechlorinated water had lower AOC levels than preozonated water, even after post disinfection.


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