scholarly journals The impact of biofilms on water quality in long pipelines

2009 ◽  
Vol 30 (1) ◽  
pp. 16
Author(s):  
Jason Plumb ◽  
Geoffrey Puzon ◽  
Maneesha Ginige

Limited water availability and increased water demand necessitates the use of long pipelines to distribute potable and non-potable water for human consumption or other purposes. The effects of microbial growth and activity on the quality of distributed water have been studied for many years, although in recent years much of this focus has shifted to understanding the effects of biofilms, rather than planktonic microorganisms, on water quality. Recently, it was estimated that 95% of all biomass in water distribution systems is in the form of pipewall biofilms, with only 5% of all biomass in the bulk water phase. Under favourable conditions, biofilms can impact water quality by increasing disinfectant demand, creating taste and odour problems, harbouring opportunistic pathogens and contributing to the potential for discoloured water events. More research is required to inform the development of guidelines for the management of biofilms in long pipelines to ensure the delivery of safe drinking water and to minimise impacts on water quality.

2018 ◽  
Vol 19 (1) ◽  
pp. 303-312
Author(s):  
A. Szuster-Janiaczyk ◽  
J. Bylka

Abstract The paper presents a detailed analysis of the quality of water pumped into a network and sampled from 39 monitoring points located on the network. A difference in the quality of water sampled from two different sources was demonstrated, as well as the impact of the mixing of the two waters in the water distribution system (WDS) on tap water quality. A mathematical model was used to identify the zones of water mixing and the areas of unfavourable hydraulic conditions (low flow rates and long retention times).


2006 ◽  
Vol 6 (5) ◽  
pp. 101-110 ◽  
Author(s):  
Y. Jaeger ◽  
S. Oberti ◽  
L. Guichot ◽  
J. Baron

Soft waters characterised with low alkalinity tend to reduce the lifetime of pipes in drinking water distribution systems. Consequently, the corrosion induced is likely to deteriorate water quality at the consumer's tap. Two different types of treatment methods are commonly used to control the corrosion effects of soft waters: (i) the addition of phosphate corrosion inhibitors, and (ii) the remineralisation process. In order to facilitate the decision making of network operator to use suitable treatment methods, a comparative pilot-scale experiment was performed. The above two treatment strategies were tested using pipes representing both drinking water distribution systems (used materials: cast iron and steel) and household plumbing systems (used material: copper). The impact of the two techniques was assessed by means of water quality monitoring (pH, metal leaching, etc) and of corrosion measurements using electrochemical probes as well as weight-loss coupons. The results obtained after a 15 month long experiment showed that remineralisation method was clearly the most effective way to control soft water corrosion. The implementation of this method resulted in a 50% reduction in metals leaching and about 40% decrease in iron corrosion rates.


2016 ◽  
Vol 2 (4) ◽  
pp. 614-630 ◽  
Author(s):  
Katherine E. Fish ◽  
A. Mark Osborn ◽  
Joby Boxall

Drinking water distribution systems (DWDS) contain complex microbial biofilm communities. Understanding the ecology of these biofilms is critical for effective management of DWDS infrastructure and maintenance of water quality.


1997 ◽  
Vol 35 (11-12) ◽  
pp. 283-287 ◽  
Author(s):  
Ph. Piriou ◽  
S. Dukan ◽  
Y. Levi ◽  
P. A. Jarrige

Of the many causes of drinking water quality deterioration in distribution systems, biological phenomena are undoubtedly the subject of the most study. They are also the most closely monitored because of short-term public health risks. A determinist model was developed to predict bacterial growth in the network and to locate the zones where the risks of biological proliferation are the highest. The model takes into account the growth of suspended and fixed bacteria, the consumption of available nutrients in the bulk water and in the biofilm layer, the influence of chlorine residual on the mortality of suspended and fixed biomass, the deposition of suspended bacteria and the detachment of biofilm cells, the influence of temperature on bacterial activity and chlorine decay. The model is constructed using hydraulic results previously generated by PICCOLO, the SAFEGE hydraulic computer model and a numerical scheme to predict bacterial count at each node and on each link of a network. The model provides an effective and each way to visualise on a computer screen variations in water quality in the network. The first model calibration was done using data obtained from a pipe loop system pilot. A validation of the model has been carried out by means of measurement campaigns on various real networks. This predictive model of bacterial growth in distribution systems is a unique approach for the study, diagnosis and management of distributed water quality. This tool is helpful for proposing strategies for the management of distribution systems and treatment plants and to define conditions and locations of high bacterial counts in relation to hydraulic conditions.


2014 ◽  
Vol 9 (3) ◽  
pp. 386-391 ◽  
Author(s):  
M. N. Dammo ◽  
A. Y. Sangodoyin

Water quality and supply are central to the socio-economic development of any nation. Scarcity of potable water results in the construction of dams and water treatment plants. Unfortunately, provision of potable water through improvement and treatment may prove to be difficult because of the socio-economic activities around a dam. This study is aimed at assessing the socio-economic activities around the Alau Dam Maiduguri, and how they affect the quality of raw water supply to Maiduguri Water Treatment Plant. The data was generated through the administration of questionnaires, and by interview and water quality analysis of dam and irrigation sites. The samples were subjected to physical, chemical and biological analysis to assess the impact of socio economic activities on the dam water, and its suitabilityfor drinking and agricultural uses. Findings reveal pollution with high concentration of nitrate (260–230 mg-NO3/l), phosphate (22–28 mg/l) and Escherichia coli (13–24 n/100 mg). This arose from improper sanitary management, inadequate public education on irrigation,indiscriminate waste disposaland some farming practices. Regular monitoring of socio-economic activities around the dam, and doing away with unhealthy waste disposal practices are recommended to safeguard the raw water supply to the treatment plant.


Water SA ◽  
2018 ◽  
Vol 44 (3 July) ◽  
Author(s):  
Moustafa S Darweesh

Water quality has become a prominent issue in the study of water distribution networks. Variable speed pumps (VSPs) can control and improve the performance of water distribution systems. However, they may have effects on the water quality. The objective of this study was to investigate the impact of VSPs on water quality. The EPANET water quality simulator was applied for modelling water age and chlorine residual in a distribution network. In addition, intrusion of an active contaminant and analysis of leakage effects on residual chlorine concentration were performed through extended period simulations. Results indicate that VSPs may have negative impacts on water quality, including increased water age during low consumption times, and reduced disinfectant residuals at peak hours. In addition, the average rate of chlorine decay for fixed speed pumps (57%) is higher than that for VSPs (54%) when a conservative contaminant (sewage water) is considered.


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