scholarly journals Evaluation of the microbial risk reduction due to selective closure of the raw water intake before drinking water treatment

2007 ◽  
Vol 5 (S1) ◽  
pp. 81-97 ◽  
Author(s):  
J. Åström ◽  
S. Petterson ◽  
O. Bergstedt ◽  
T. J. R. Pettersson ◽  
T. A. Stenström
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Water Intake ◽  
Drinking Water Treatment ◽  
Threshold Level ◽  
Waterborne Diseases ◽  
Raw Water ◽  
Indicator Organisms ◽  
Microbial Risk ◽  
E Coli

Short-term peaks in pathogen concentrations may increase the risks for waterborne diseases considerably. In this study the occurrence of indicator organisms and pathogens in the river Göta älv at the raw water intake to Göteborg was evaluated and related to risk for drinking water consumption. About half of the 24 pathogen samples, taken during event and non-event conditions, were positive for at least one of the following: Cryptosporidium, Giardia, norovirus, enterovirus, Campylobacter and E. coli O157. Positive pathogen detects were often associated with heavy rainfalls and viruses with a sewage emergency discharge. The annualised probability of infection from this type of event was calculated from pathogen concentrations in a QMRA model. Given that the water intake is not closed, the risk given present water treatment seems to be acceptable for Giardia; however, it is at a borderline for Cryptosporidium and insufficient for noro- and enteroviruses. Present results emphasise the need for an appropriate intake regulation with respect to high pathogen loads, as the risk increases with time of exposure to pathogen contaminants. Rather than a threshold level on E. coli, reports on upstream microbial discharges are valuable for quick pathogen indications.

scholarly journals Identification and management of microbial contaminations in a surface drinking water source

2007 ◽  
Vol 5 (S1) ◽  
pp. 67-79 ◽  
Author(s):  
J. Åström ◽  
T. J. R. Pettersson ◽  
T. A. Stenström
Keyword(s):  
Drinking Water ◽  
Water Intake ◽  
Surface Waters ◽  
Microbial Contamination ◽  
Water Source ◽  
Drinking Water Source ◽  
Raw Water ◽  
Indicator Organisms ◽  
E Coli ◽  
The City

Microbial contamination of surface waters constitutes a health risk for drinking water consumers which may be lowered by closing the raw water intake. We have evaluated microbial discharge events reported in the river Göta älv, which is used for raw water supply to the city of Göteborg. Elevated levels of faecal indicator bacteria were observed during periods of closed raw water intake. High bacteria levels were, however, also occasionally detected during periods of open intake, probably as a result of microbial discharge far upstream in the river which may be difficult to predict and manage by closing the intake. Accumulated upstream precipitations, resulting in surface runoff and wastewater contaminations in the catchment, correlated positively with the levels of total coliforms, E. coli, intestinal enterococci and sulfite-reducing clostridia. Levels of faecal indicator organisms were negatively correlated to the water temperature due to enhanced survival at lower temperatures. Wastewater discharges from a municipality located just upstream of the water intake resulted in elevated E. coli concentrations downstream at the raw water intake for Göteborg. To improve the prediction of microbial contaminations within the river Göta älv, monitoring data on turbidity and upstream precipitation are of particular importance.

scholarly journals OPTIMIZATION OF THE DRINKING WATER TREATMENT PROCESS OF A SUGAR PLANT STATION IN COTE DIVOIRE

2021 ◽  
Vol 9 (01) ◽  
pp. 512-524
Author(s):  
Konan Lopez Kouame ◽  
◽  
Nogbou Emmanuel Assidjo ◽  
Andre Kone Ariban ◽  
◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Treatment Process ◽  
Polynomial Regression ◽  
Drinking Water Treatment ◽  
Optimal Dose ◽  
Raw Water ◽  
Water Treatment Process ◽  
Jar Test ◽  
Coagulation And Flocculation

This article presents an optimization of the drinking water treatment process at the SUCRIVOIRE treatment station. The objective is to optimize the coagulation and flocculation process (fundamental process of the treatment of said plant)by determining the optimal dosages of the products injected and then proposes a program for calculating the optimal dose of coagulant in order to automatically determine the optimal dose of the latter according to the raw water quality. This contribution has the advantage of saving the user from any calculations the latter simply enters the characteristics of the raw effluent using the physical interface of the program in order to obtain the optimum corresponding coagulant concentration. For the determination of the optimal coagulant doses, we performed Jar-Test flocculation tests in the laboratory over a period of three months. The results made it possible to set up a polynomial regression model of the optimal dose of alumina sulfate as a function of the raw water parameters. A program for calculating the optimal dose of coagulant was carried out on Visual Basic. The optimal doses of coagulant obtained vary from 25, 35, 40 and 45 mg/l depending on the characteristics of the raw effluent. The model obtained is: . Finally, verification tests were carried out using this model on the process. The results obtained meet the WHO drinkability standards for all parameters for a settling time of two hours.

A novel low-cost multi-barrier system for drinking water treatment in rural and suburban areas

2019 ◽  
Vol 15 (1) ◽  
pp. 48-65 ◽  
Author(s):  
Stephen Siwila ◽  
Isobel C. Brink
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Granular Media ◽  
Low Cost ◽  
Water System ◽  
Drinking Water Treatment ◽  
Fecal Coliforms ◽  
E Coli ◽  
Suburban Areas ◽  
Novel Concept

Abstract A low-cost multi-barrier drinking water system incorporating geotextile fabric for pre-filtration, silver-coated ceramic granular media (SCCGM) for filtration and disinfection, granular activated carbon (GAC) as an adsorption media and a safe storage compartment for treated water has been developed and tested. The developed system offers a novel concept of point-of-use drinking water treatment in rural and suburban areas of developing countries. The system is primarily aimed at bacterial and aesthetic improvement and has been optimised to produce >99.99% E. coli and fecal coliforms removal. Although particular emphasis was placed on the elimination of bacteria, improvement of the acceptability aspects of water was also given high priority so that users are not motivated to use more appealing but potentially unsafe sources. This paper discusses key system features and contaminant removal performance. A system using SCCGM only was also tested alongside the multi-barrier system. Strengths and weaknesses of the system are also presented. Both the developed and SCCGM-only systems consistently provided >99.99% E. coli and fecal coliforms removal at an optimum flow of 2 L/h. The developed system significantly recorded improvements of aesthetic aspects (turbidity, color, taste and odor). Average turbidity removals were 99.2% and 90.2% by the multi-barrier and SCCGM-only systems respectively.

scholarly journals Simulation of NOM events in pilot plant evaluation of DAF/Ozone/BAC for drinking water treatment

2017 ◽  
Vol 17 (6) ◽  
pp. 1793-1800
Author(s):  
Y. Yan ◽  
M. Carter ◽  
A. Mercer
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Pilot Plant ◽  
Drinking Water Treatment ◽  
Natural Occurrence ◽  
Raw Water ◽  
Humic Materials ◽  
Pilot Investigation ◽  
Brewing Method ◽  
Plant Evaluation

Abstract Pilot plant testing is invaluable for ascertaining the robustness of water treatment processes against raw water quality events such as turbidity and colour spikes, whether it be for stress testing of an existing process or designing of a new process. Unfortunately, the natural occurrence of such events (particularly colour) can be difficult to predict and commercial humic materials generally fail to closely match the indigenous natural organic matter (NOM) present in the raw water. Therefore, it is highly desirable to be able to simulate NOM event conditions. This paper describes a simple brewing method that we developed and used in our recent pilot plant evaluation of a proposed DAF/Ozone/BAC process for drinking water treatment. Using this method we successfully prepared, by using fallen leaves etc. collected from the local catchment area, large quantities of a concentrated NOM stock solution with its specific ultraviolet absorbance (SUVA), when diluted, very close to the median SUVA of historical NOM events. The brewed solution showed broadly similar NOM characteristics to those of the raw water encountered during the pilot investigation period in terms of molecular weight distribution and fractionation. The coagulation behaviour was also examined for the spiked and non-spiked raw water.

scholarly journals PENINGKATAN KUALITAS AIR BAKU DENGAN PROSES BIOFILTER TERCELUP MENGGUNAKAN MEDIA STRUKTUR SARANG TAWON

2018 ◽  
Vol 7 (1) ◽  
Author(s):  
Nusa Idaman Said ◽  
Arie Herlambang
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Water Treatment ◽  
River Water ◽  
Residence Time ◽  
Drinking Water Treatment ◽  
Organic Substances ◽  
Raw Water ◽  
Treatment Unit ◽  
High Organic Matter

Contamination of rivers has reached an alarming level, especially in the rivers passing through major cities, agricultural areas and industrial areas. Among the contaminants that often appear dominant and very disturbing is the organic substance. The existence of high organic matter within the river water is often expressed in permanganate number that has passed the quality standard. River that contain high organic matter usually the water smell and the color is black, besides it can also cause disturbances in the water treatment process, which is an increasing use of coagulants, chlorine, activated carbon, and the emergence of substances that are not desired, and the quality of treatment results are unsatisfactory. Many ways to reduce the organic matter in river water, one of them is by using the biofilter honeycomb structure. The target of the reduction of organic substances is that the river water could be used as a raw drinking water quality standards or meet the category B, Regulation of Jakarta Governor Number 582, 1995. Raw water used for this study were taken from Krukut River which is the raw water for Regional Water Company PALYJA, Production Installation III Cilandak, South Jakarta and Cengkareng Drain river water, which is currently used as a source of raw water for PAM Taman Kota, West Jakarta using a biofilter reactor aerobic system, the capacity of 50 - 200 m3, Capasity of Blowers 300 l /min, Residence Time 6 hours up to 1 hour. Test results on the residence time of 1 hour, parameters pH, TSS, turbidity, organic substances, detergents, manganese, ammonia, nitrite, nitrate, can meet the standard, except for iron which still exceeds the standard. To improve the removal  efficiency of organic matter and iron, at the beginning of processing before entering into the drinking water treatment unit need to be added powder active carbon and an oxidizing agent with a sufficient dose. Keywords: Organic substances, biofilter, aerobic, honeycomb plastic media.

scholarly journals Characterization of microbial regrowth potential shaped by advanced drinking water treatment

2021 ◽  
Author(s):  
Ikuro Kasuga ◽  
Hitomi Nakamura ◽  
Futoshi Kurisu ◽  
Hiroaki Furumai
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Organic Carbon ◽  
Microbial Communities ◽  
Drinking Water Treatment ◽  
Raw Water ◽  
Assimilable Organic Carbon ◽  
Water Transportation ◽  
Microbial Regrowth ◽  
Treatment Step

Abstract Microbial regrowth in premise plumbing is a threat to water safety. Disinfectant residuals are often diminished during water transportation and stagnation, leading to the regrowth of opportunistic pathogens. Although microbial regrowth potential is mostly determined by water treatment, little is known about how each treatment step affects two key factors that contribute to microbial regrowth potential: biodegradable organic matter and microbial abundance. In this study, we operated annular reactors to evaluate the microbial regrowth potential of water shaped after each treatment step in a full-scale drinking water treatment plant with ozonation and biological activated carbon filtration. The assimilable organic carbon and total cell count (TCC) were stable at all treatment steps during the sampling period from July to October 2015. The assimilable organic carbon consumption and TCC net increase in the annular reactors indicated that apparent growth yields (cell number base) of microbial communities were different in each reactor. Regrowth potential evaluated by indigenous microbial community in finished water was reduced to 22% of that in raw water, while 75% of assimilable organic carbon in raw water remained in finished water. It suggested that treatment performance evaluated by indigenous microbial communities was better than that evaluated by assimilable organic carbon.

Occurrence of microcystins in raw water sources and treated drinking water of Finnish waterworks

2001 ◽  
Vol 43 (12) ◽  
pp. 225-228 ◽  
Author(s):  
K. Lahti ◽  
J. Rapala ◽  
A-L. Kivimäki ◽  
J. Kukkonen ◽  
M. Niemelä ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Drinking Water Treatment ◽  
Water Sources ◽  
World Health ◽  
Bank Filtration ◽  
Raw Water ◽  
Guide Value ◽  
The World ◽  
Treated Drinking Water

Problems caused by cyanobacteria are common around the world and also in raw water sources of drinking water treatment plants. Strains belonging to genera Microcystis, Anabaena and Planktothrix produce potent hepatotoxins, the microcystins. Laboratory and pilot scale studies have shown that microcystins dissolved in water may pass the conventional surface water treatment processes. In 1998 the World Health Organization proposed a guide value of 1 μg/L for microcystin-LR (MC-LR) in drinking water. The purpose of this research was to study the occurrence of microcystins in raw water sources of surface waterworks and in bank filtration plants and to evaluate the removal of microcystins in operating waterworks. Four bank filtration plants and nine surface waterworks using different processes for water treatment were monitored. Phytoplankton was identified and quantified, and microcystins analysed with sensitive immunoassay. Microcystin occurrence in selected water samples was verified with HPLC and a protein phosphatase inhibition method. Microcystins were detected sporadically in raw water sources of most of the waterworks. In two raw water supplies toxins were detected for several months. The highest microcystin concentrations in incoming raw water were approximately 10 μg/L MC-LR equivalents. In treated drinking water microcystins were detected occasionally but the concentrations were always below the guide value proposed by WHO.

scholarly journals Preparation of a Zirconia-Based Ceramic Membrane and Its Application for Drinking Water Treatment

Symmetry ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 933
Author(s):  
Mohamed Boussemghoune ◽  
Mustapha Chikhi ◽  
Fouzia Balaska ◽  
Yasin Ozay ◽  
Nadir Dizge ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Ceramic Membrane ◽  
Slip Casting ◽  
Drinking Water Treatment ◽  
Raw Water ◽  
Permeate Flux ◽  
Filtration Time ◽  
X Ray ◽  
Total Coliforms

This work concerns the preparation of a mineral membrane by the slip casting method based on zirconium oxide (ZrO2) and kaolin. The membrane support is produced from a mixture of clay (kaolin) and calcium carbonate (calcite) powders using heat treatment (sintering). Membrane and support characterization were performed by Scanning Electron Microscopy (SEM), X-ray Fluorescence (XRF), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Raman Spectroscopy. The prepared mineral membrane was tested to treat drinking water obtained from different zones of the El Athmania (Algeria) water station (raw, coagulated, decanted, and bio filtered water). Experimental parameters such as permeate flux, turbidity, and total coliforms were monitored. The results showed that the mineral membrane was mainly composed of SiO2 and Al2O3 and the outer surface, which represented the membrane support, was much more porous than the inner surface where the membrane was deposited. The permeate flux of the raw water decreased with filtration time, due to a rejection of the organic matters contained in the raw water. Moreover, the absence of total coliforms in the filtrate and the increase in concentration in the concentrate indicate that the prepared mineral membrane can be used for drinking water treatment.

Speciation and seasonal variation of various disinfection by-products in a full-scale drinking water treatment plant in East China

2019 ◽  
Vol 19 (6) ◽  
pp. 1579-1586 ◽  
Author(s):  
Xiang-Ren Zhou ◽  
Yi-Li Lin ◽  
Tian-Yang Zhang ◽  
Bin Xu ◽  
Wen-Hai Chu ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Water Treatment Plant ◽  
Full Scale ◽  
East China ◽  
Raw Water ◽  
Drinking Water Treatment Plant ◽  
By Products

Abstract The objective of this research was to study the occurrence and seasonal variations of disinfection by-products (DBPs), including traditional carbonaceous and emerging nitrogenous DBPs, in a full-scale drinking water treatment plant (DWTP) for nearly 2 years. The removal efficiencies of each DBP through the treatment processes were also investigated. This DWTP takes raw water from the Yangtze River in East China. The quality of the raw water used in this DWTP varied with different seasons. The results suggested that DBP concentrations of the finished water were higher in spring (82.33 ± 15.12 μg/L) and summer (117.29 ± 9.94 μg/L) with higher dissolved organic carbon (DOC) levels, but lower in autumn (41.10 ± 5.82 μg/L) and winter (78.47 ± 2.74 μg/L) with lower DOC levels. Due to the increase of bromide concentration in spring and winter, more toxic brominated DBPs increased obviously and took up a greater proportion. In this DWTP, DBP concentrations increased dramatically after pre-chlorination, especially in summer. It is noteworthy that the removal of DBPs during the subsequent treatment was more obvious in spring than in the other three seasons because the pH value is more beneficial to coagulation in spring.

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