Characterization of microparticles in raw, treated, and distributed waters by means of elemental and particle size analyses

2004 ◽  
Vol 50 (12) ◽  
pp. 71-78 ◽  
Author(s):  
T. Inoue ◽  
Y. Matsui ◽  
Y. Terada ◽  
K. Baba ◽  
T. Matsushita
Keyword(s):  
Particle Size ◽  
Water Treatment ◽  
Suspended Solids ◽  
Suspended Particles ◽  
Raw Water ◽  
Sand Filtration ◽  
Treated Water ◽  
Al Content ◽  
Solids Concentration ◽  
Distribution Process

The elemental composition and particle size distribution of suspended particles in raw water, treated water, and distributed water were determined to understand the behavior of particles during the water treatment-distribution process. The weight of suspended particles collected on a 0.6-µm filter was 1.1 times (raw water), 1.4 times (treated water), and 1.5 times (distributed water) that collected on a 2.7-μ;m filter, suggesting that smaller particles may remain after conventional water treatment. Organic suspended particles were removed less efficiently than inorganic suspended particles. After sand filtration, the Al content in the fixed suspended solids (FSS) markedly increased, indicating that either a small percentage of aluminium floc passed through during sand filtration or dissolved aluminum precipitated after sand filtration. The Mn and Fe concentrations increased after chlorination. The percentages of carbon and nitrogen in the volatile suspended solids (VSS) were roughly the same in the raw, treated, and distributed waters. The carbon/nitrogen/phosphate/VSS ratios indicated that the VSS of the suspended particles consisted of organic matter originating from microorganisms. The major constituents of the FSS in the treated and distributed waters were compounds of Fe, Al, Ca, Mg, and Mn, but these compounds accounted for only 16% or less of the FSS in raw water, indicating the existence of Si compounds. In distribution pipes, the total suspended solids concentration, especially the FSS concentration, was higher than that of water just after treatment. The Fe concentration in distributed water increased, probably due to oxidation and rusting of iron pipes.

Suspended particles in the drinking water of two distribution systems

2001 ◽  
Vol 1 (4) ◽  
pp. 237-245 ◽  
Author(s):  
V. Gauthier ◽  
B. Barbeau ◽  
R. Millette ◽  
J.-C. Block ◽  
M. Prévost
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Organic Matter ◽  
Distribution System ◽  
Distribution Systems ◽  
Suspended Solids ◽  
Suspended Particles ◽  
Raw Water ◽  
Remote Locations ◽  
Dissolved Matter

The concentrations of suspended particles were measured in the drinking water of two distribution systems, and the nature of these particles documented. The concentrations of particulate matter were invariably found to be small (maximum 350 μg/L). They are globally in the very low range in comparison with dissolved matter concentrations, which are measured in several hundreds of mg/L. Except during special water quality events, such as turnover of the raw water resource, results show that organic matter represents the most important fraction of suspended solids (from 40 to 76%) in treated and distributed water. Examination of the nature of the particles made it possible to develop several hypotheses about the type of particles penetrating Montreal's distribution system during the turnover period (algae skeleton, clays). These particles were found to have been transported throughout the distribution systems quite easily, and this could result in the accumulation of deposits if their surface charge were ever even slightly destabilised, or if the particles were to penetrate the laminar flow areas that are fairly typical of remote locations in distribution systems.

scholarly journals Cyanobacteria and microcystin contamination in untreated and treated drinking water in Ghana

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Gloria Naa Dzama Addico ◽  
Jörg D. Hardege ◽  
Jiri Kohoutek ◽  
Kweku Amoaku Atta DeGraft-Johnson ◽  
Pavel Babica
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Human Health ◽  
Metropolitan Area ◽  
Cyanobacterial Blooms ◽  
Maximal Concentration ◽  
Raw Water ◽  
Treated Water ◽  
Treated Drinking Water ◽  
Who Guideline

<p>Although cyanobacterial blooms and cyanotoxins represent a worldwide-occurring phenomenon, there are large differences among different countries in cyanotoxin-related human health risk assessment, management practices and policies. While national standards, guideline values and detailed regulatory frameworks for effective management of cyanotoxin risks have been implemented in many industrialized countries, the extent of cyanobacteria occurrence and cyanotoxin contamination in certain geographical regions is under-reported and not very well understood. Such regions include major parts of tropical West and Central Africa, a region constisting of more than 25 countries occupying an area of 12 million km<sup>2</sup>, with a total population of 500 milion people. Only few studies focusing on cyanotoxin occurrence in this region have been published so far, and reports dealing specifically with cyanotoxin contamination in drinking water are extremely scarce. In this study, we report seasonal data on cyanobacteria and microcystin (MC) contamination in drinking water reservoirs and adjacent treatment plants located in Ghana, West Africa. During January-June 2005, concentrations of MCs were monitored in four treatment plants supplying drinking water to major metropolitan areas in Ghana: the treatment plants Barekese and Owabi, which serve Kumasi Metropolitan Area, and the plants Kpong and Weija, providing water for Accra-Tema Metropolitan Area. HPLC analyses showed that 65% samples of raw water at the intake of the treatment plants contained intracellular MCs (maximal detected concentration was 8.73 µg L<sup>-1</sup>), whereas dissolved toxins were detected in 33% of the samples. Significant reduction of cyanobacterial cell counts and MC concentrations was achieved during the entire monitoring period by the applied conventional water treatment methods (alum flocculation, sedimentation, rapid sand filtration and chlorination), and MC concentration in the final treated water never exceeded 1 µg L<sup>-1</sup> (WHO guideline limit for MCs in drinking water). However, cyanobacterial cells (93-3,055 cell mL<sup>-1</sup>) were frequently found in the final treated water and intracellular MCs were detected in 17% of the samples (maximal concentration 0.61 µg L<sup>-1</sup>), while dissolved MCs were present in 14% of the final treated water samples (maximal concentration 0.81 µg L<sup>-1</sup>). It indicates a borderline efficiency of the water treatment, thus MC concentrations in drinking water might exceed the WHO guideline limit if the treatment efficiency gets compromised. In addition, MC concentrations found in the raw water intake might represent significant human health risks for people living in areas with only a limited access to the treated or underground drinking water.</p>

Halogenated Phenols in Water at Forty Canadian Potable Water Treatment Facilities

1986 ◽  
Vol 69 (5) ◽  
pp. 807-810
Author(s):  
Bishop B Sithole ◽  
David T Williams
Keyword(s):  
Water Treatment ◽  
Water Samples ◽  
Potable Water ◽  
Treatment Plant ◽  
Water Type ◽  
Raw Water ◽  
Mean Values ◽  
Treated Water ◽  
Halogenated Phenols ◽  
Potable Water Treatment

Abstract Samples of raw and treated water were collected once in each of 3 seasons at 40 potable water treatment plants across Canada and were analyzed for phenol and 33 halogenated phenolic compounds including chlorophenols, bromophenols, bromochlorophenols, and chloroguaiacols. Eighteen of the compounds were not found at any treatment plant; phenol and each of the remaining halogenated phenols were found in at least 1 sample. Pentachlorophenol was the only halogenated phenolic compound found in more than 20% of the raw water samples in the fall and winter samples at levels up to 53 ng/L with mean values of 1.9 and 2.8 ng/L, respectively. No halogenated phenols were detected in raw water summer samples. The halogenated phenols found most frequently in treated water samples were 4-chloro-, 2,4-dichloro-, 2,4,6- trichloro-, and bromodichlorophenols. Mean values were less than 15 ng/L and maximum values seldom exceeded 100 ng/L. Most of the positive values for the treated water samples were found at 8 of the 40 treatment plants but no correlations could be found between halogenated phenol levels and raw water type, treatment process, or chemical dosages.

Ten Year Survey of Salmonella and Enterovirus in Raw and Treated Waters in the Great São Paulo Area, Brazil

1986 ◽  
Vol 18 (10) ◽  
pp. 53-60 ◽  
Author(s):  
M. T. Martins ◽  
P. S. Sanchez ◽  
E. Marques ◽  
C. K. Monteiro ◽  
A. G. Molina
Keyword(s):  
Water Treatment ◽  
Pathogenic Bacteria ◽  
Monitoring Program ◽  
Sao Paulo ◽  
Residual Chlorine ◽  
São Paulo ◽  
Raw Water ◽  
Poliovirus Type ◽  
Treated Water

The monitoring program for Enterovirus and Salmonella in raw and treated waters, from nine water treatment plants of Great São Paulo, Brazil, has been developed by CETESB- The São Paulo State Environmental Protection Agency under a contract with SABESP - Water Industry and Sewage Works Company, since 1976. For Salmonella analysis a total of 904 samples of raw water and 997 of treated water were analysed during these last 10 years. A percentage of 30.6 of 904 raw water samples revealed the presence of Salmonella. These pathogenic bacteria were absent in treated water. For Enterovirus, 383 samples of raw water were analysed, out of these 14.9% revealed the presence of virus. From a total of 366 viruses isolated 195 (53.3%) were Poliovirus, 79 (21.6%) were Echovirus, 30 (8.2%) were Coxsackievirus and 62 (16.9%) isolates were untyped. As far as treated water is concerned for the 10 year study, only 3 out of 975 samples were positive for viruses (Poliovirus type 2, Coxsackie A16, and one isolate untyped). Coliforms and Salmonella were not detected in these 3 samples. Residual chlorine was present. In the sample where Poliovirus type 2 was present, free residual chlorine was 1.5 mg/L and pH 9.2. This survey demonstrated that the conventional procedures for water treatment used by SABESP were in general efficient for Enterovirus and Salmonella removal.

Coagulation-Flocculation in Water Treatment using Calotropis Procera Leaves: A case study of River in Kaduna, Nigeria

2014 ◽  
Vol 67 (4) ◽  
Author(s):  
Jibrin Mohammed Danlami ◽  
Agus Arsad ◽  
Muhammad Abbas Ahmad Zaini ◽  
Abdullahi Mohammed Evuti ◽  
Ankeli Ogbole
Keyword(s):  
Particle Size ◽  
Water Treatment ◽  
Treatment Time ◽  
Low Cost ◽  
World Health ◽  
Calotropis Procera ◽  
Sampling Location ◽  
Water And Wastewater Treatment ◽  
Constant Weight ◽  
Treated Water

This research was carried out to evaluate the effectiveness Calotropis procera leaves as an alternative to the use of chemicals as coagulants in water treatment. Calotropis procera leaves were plugged, washed with distilled water, cut into small pieces and then dried in an oven to a constant weight. After which the leaves were grinded into various particle sizes of 1 mm, 2 mm and 0.71 mm. Raw water from River Kaduna at Kabala and Kakuri areas within Kaduna metropolis were treated with different samples classified based on the dried Calotropis procera leaves particle size and weight, sampling location and the treatment time. The physico-chemical characteristics of the treated samples were all within the allowable standard by World Health Organization (WHO). The results show that the treated water sample D with 0.71 mm particle size and 40 g weight of the dried Calotropis procera leaves gave the highest percentage reduction in turbidity. Treatment of the samples with Calotropis procera leaves gave a significant reduction in coliform count from 21 per 100 ml to 1 per 100 ml in treated water samples E and F. This study shows that Calotropis procera can be used as a low-cost, environmentally friendly substitute coagulant for water and wastewater treatment.

scholarly journals Particle size analysis for improved sedimentation and filtration in waste water treatment

1999 ◽  
Vol 39 (8) ◽  
pp. 99-106 ◽  
Author(s):  
A. Tiehm ◽  
V. Herwig ◽  
U. Neis
Keyword(s):  
Waste Water ◽  
Particle Size ◽  
Water Treatment ◽  
Suspended Solids ◽  
Waste Water Treatment ◽  
Particle Size Analysis ◽  
Distribution Functions ◽  
Particulate Phosphorus ◽  
Size Analysis ◽  
Secondary Effluents

Size distributions of particle mass, chemical oxygen demand (COD) and phosphorus at four municipal waste water treatment plants were investigated by fractionation of samples through 0.1-8.0 μm polycarbonate filters and 32-125 μm sieves, respectively. Particle size analysis of primary and secondary effluents at each plant showed significantly different size distribution functions. These distribution functions remained constant with respect to time under dry weather conditions so they can be considered as characteristic patterns for each sample location. Advanced treatment by deep bed filtration can be improved by taking into consideration the distribution pattern in the secondary effluents. In raw sewage and primary effluents 45-90% of COD and 35-80% of phosphorus were associated with suspended solids. In the secondary effluents particulate COD drops to 14-45% but particulate phosphorus increases to 55-80%. Conclusions are drawn for a better design of advanced contaminant reduction in connection with suspended solids removal processes.

scholarly journals Influence of density flow on treated water turbidity in a sedimentation basin with inclined plate settler

2017 ◽  
Vol 17 (4) ◽  
pp. 1140-1148
Author(s):  
K. Takata ◽  
R. Kurose
Keyword(s):  
Drinking Water ◽  
Particulate Matter ◽  
Water Treatment ◽  
Drinking Water Treatment ◽  
Raw Water ◽  
Inclined Plate ◽  
Treated Water ◽  
Sedimentation Basin ◽  
Density Flow ◽  
Upward Velocity

The removal efficiency of particulate matter from a sedimentation basin with an inclined plate settler in drinking water treatment facilities is sometimes reduced by density flow caused by temperature increases in the raw water. In this study, the structure of the density flow and its prevention are investigated by means of three-dimensional computational fluid dynamics (CFD). The results of CFD show that upward velocity is uniform and normal operations are performed before the increase in inlet water temperatures. After the onset of a temperature increase in the raw water, the upward flow velocity on the inclined plate settler increases, especially in the upstream zone of the plate. This velocity increment has a strong correlation with increase in turbidity as a result of the overflow of particulate matter. The effects of the installation of baffle plates on the inclined plate settler to reduce turbidity were explored. The CFD results using baffle plates show a significant decrease in upward velocity on the inclined plate settler. This suggests that baffle plates are effective in suppressing the overflow of particulate matter. To verify the prediction by CFD, baffle plates were installed in a drinking water treatment facility. The results show that the turbidity of treated water was reduced by the proposed procedure.

Particle and microorganism removal in floating plastic media coupled with microfiltration membrane for surface water treatment

2005 ◽  
Vol 51 (10) ◽  
pp. 93-100 ◽  
Author(s):  
C. Chiemchaisri ◽  
W. Chiemchaisri ◽  
T. Kornboonraksa ◽  
C. Dumrongsukit ◽  
S. Threedeach ◽  
...  
Keyword(s):  
Water Treatment ◽  
Surface Water ◽  
Filtration Rate ◽  
Coliform Bacteria ◽  
Transmembrane Pressure ◽  
Raw Water ◽  
Microfiltration Membrane ◽  
Treated Water ◽  
Surface Water Treatment ◽  
Plastic Media

Floating plastic media followed by hollow fiber microfiltration membrane was applied for surface water treatment. The performance of the system in terms of particle and microorganisms was investigated. The floating filter was examined at different filtration rates of 5, 10 and 15 m3/m2.h. Treated water was then fed into a microfiltration unit where different filtration rates were examined at 0.6, 1.0 and 1.4 m3/m2.d. It was found that polyaluminum chloride was the best coagulant for the removal of particle, algae and coliform bacteria. Average turbidity in treated water from the floating plastic media filter was 3.3, 12.2 and 15.5 NTU for raw water of 80 NTU and 12.9, 11.7 and 31.2 NTU for raw water of 160 NTU after 6 hours at the filtration rates of 5, 10 and 15 m3/m2.h, respectively. The microfiltration unit could further reduce the turbidity to 0.2–0.5 NTU with low transmembrane pressure development of 0.3–3.7 kPa. Microfiltration membrane could retain most of algae and coliform bacteria remaining in the effluent from the pretreatment unit. It was found that at higher turbidity, algae and coliform bacteria removal efficiencies were achieved at lower filtration rate of the system of 5 m3/m2.h whereas a higher filtration rate of 15 m3/m2.h yielded better coliphage removal.

Use of chitosan in coagulation flocculation of raw water of Keddara and Beni Amrane dams

2011 ◽  
Vol 11 (2) ◽  
pp. 202-210 ◽  
Author(s):  
Hassiba Zemmouri ◽  
Slimane Kadouche ◽  
Hakim Lounici ◽  
Madjid Hadioui ◽  
Nabil Mameri
Keyword(s):  
Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Raw Water ◽  
Treated Water ◽  
Surface Water Treatment ◽  
Aluminium Sulfate ◽  
Low Concentrations ◽  
Ph Range ◽  
Different Doses

The effectiveness of chitosan as a coagulant flocculant in surface water treatment has been studied. Tests were carried out in laboratory on treated and raw water. The treated water was mixed with high and low concentrations of bentonite to simulate turbid water. This treated water provides from water treatment plant of Algiers (Boudouaou site) which is supplied by both dams of Keddara and Beni Amrane. The raw water comes directly from these two dams. Chitosan with 85% degree of deacetylation and derived from crab chitin has been used. The performance of coagulation flocculation process has been assessed by measuring the supernatant turbidity for different doses of chitosan, initial turbidity, water quality and pH. The obtained results show that chitosan can be used in a large pH range. Chitosan is effective for coagulation of bentonite suspension and for raw water with high initial turbidity. Otherwise, chitosan is inefficient for raw water with very low initial turbidity. In this case, the use of chitosan as aid coagulant with aluminium sulfate (main coagulant) allows more effectiveness in removing turbidity.

Suspended Solids Removal Efficiencies of a Barrier Board that Pre-Treats High-Turbidity Raw Water

2012 ◽  
Vol 253-255 ◽  
pp. 969-974
Author(s):  
Jian Liang Chen ◽  
Yi Kuo Chang ◽  
Chin Hsing Lai ◽  
Yun Hwei Shen
Keyword(s):  
Suspended Solids ◽  
Removal Rate ◽  
Initial Period ◽  
Raw Water ◽  
High Concentration ◽  
Solids Concentration ◽  
Gravity Settling ◽  
High Turbidity ◽  
Solids Removal

It tends to produce high-turbidity raw water during the initial period of typhoons or storms and affect the operation of the purifying system. In this research, Raw water suspended solids roughly to 5,000-9,000 mg/l, the removal rate can be to about 70%-90 %, and reduced to 800 mg/l or less, 8 ml/s minimum about 100-400 mg/l. Overall, the quality of effluent water with the overflow water height increased removal rate rose gradually reduce the suspended solids concentration, gravity settling and effective appear, especially the section Ⅳ region (40 cm) removal are more than 80 %, flow 100 ml/s to 84 %, compared with I (10 cm) with 100 ml/s for 74 %, with obvious benefits. The overflow height of the flow of 8 ml/s, and suspended solids by the inlet concentration at 7,400 mg/l to 8,700 mg/l, down to the effluent concentrations are below 300 mg/l, which overflow height of 20, 30, and 40 cm can be reduced to below 200 mg/l, showing that gravitational sedimentation can significantly remove the high concentration of suspended solids.

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