Contamination potential of drinking water distribution network biofilms

2004 ◽  
Vol 49 (11-12) ◽  
pp. 277-286 ◽  
Author(s):  
J. Wingender ◽  
H.-C. Flemming
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution Network ◽  
Galvanized Steel ◽  
Detection Methods ◽  
Coliform Bacteria ◽  
Plate Count ◽  
Drinking Water Distribution ◽  
Biofilm Development

Drinking water distribution system biofilms were investigated for the presence of hygienically relevant microorganisms. Early biofilm formation was evaluated in biofilm reactors on stainless steel, copper, polyvinyl chloride (PVC) and polyethylene coupons exposed to unchlorinated drinking water. After 12 to 18 months, a plateau phase of biofilm development was reached. Surface colonization on the materials ranged between 4 × 106 and 3 × 107 cells/cm2, with heterotrophic plate count (HPC) bacteria between 9 × 103 and 7 × 105 colony-forming units (cfu)/cm2. Established biofilms were investigated in 18 pipe sections (2 to 99 years old) cut out from distribution pipelines. Materials included cast iron, galvanized steel, cement and PVC. Colonization ranged from 4 × 105 to 2 × 108 cells/cm2, HPC levels varied between 101 and 2 × 105 cfu/cm2. No correlation was found between extent of colonization and age of the pipes. Using cultural detection methods, coliform bacteria were rarely found, while Escherichia coli, Pseudomonas aeruginosa and Legionella spp. were not detected in the biofilms. In regular operation, distribution system biofilms do not seem to be common habitats for pathogens. However, nutrient-leaching materials like rubber-coated valves were observed with massive biofilms which harboured coliform bacteria contaminating drinking water.

Assessment of Lisbon drinking water distribution network biofilm colonization and associated hazards

2008 ◽  
Vol 8 (4) ◽  
pp. 421-426
Author(s):  
J. Menaia ◽  
M. Benoliel ◽  
A. Lopes ◽  
C. Neto ◽  
E. Ferreira ◽  
...  
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Water Distribution Network ◽  
Storage Tanks ◽  
Water Pipe ◽  
Cultural Methods ◽  
Drinking Water Distribution ◽  
And Storage

Concerns arise from the possible occurrence of pathogens in drinking water pipe biofilms and storage tank sediments. In these studies, biofilm samples from pipes and sediments from storage tanks of the Lisbon drinking water distribution system were analyzed. Protein determinations and heterotrophic counts on pipe biofilm samples were used to assess the Lisbon network sessile colonization intensity and distribution. Indicator and pathogenic microorganisms were analyzed in pipe biofilm samples, as well as in storage tanks biofilm and sediments, by using cultural methods and PCR, to assess risks. Results have shown that the Lisbon network sessile colonization is relatively weak in intensity. In addition, no meaningful hazards were apparent for both the network biofilm and the storage tanks biofilm and sediments.

scholarly journals Hydraulic optimization of the physical parameters of a drinking water distribution system

2021 ◽  
Vol 2139 (1) ◽  
pp. 012013
Author(s):  
C A Bonilla-Granados ◽  
N J Cely-Calixto ◽  
G A Carrillo Soto
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution System ◽  
Water Distribution Network ◽  
Hydraulic Modeling ◽  
Physical Parameters ◽  
Drinking Water Distribution System ◽  
Drinking Water Distribution

Abstract Drinking-water distribution systems are generally designed with methodologies based on trial-and-error tests, which generate feasible results. However, these trials are not the most economical and reliable solution since they do not consider the optimization of the network. For the present work, the hydraulic model of the drinking water distribution network of San José de Cúcuta, Colombia, was optimized by applying the concept of resilience rate and minimum cost. The development of the work consisted of the hydraulic modeling of the physical components of the network in EPANET software, as well as the application of calculations of the connectivity coefficient and the unitary power of each section. With the data obtained from the modeling and calculations, the physical parameters were optimized, and the cost-benefit ratio was estimated. It was found that the current drinking water distribution system does not have a power surplus to overcome a system failure. The optimization increased the total energy surplus of the network (261%) and the resilience rate (585%). Also, the connectivity coefficient was improved with an average value of 0.95. The hydraulic optimization methodology applied resulted in a network resilient to system failures.

Evaluating the potential of biofilm control in water supply systems by removal of phosphorus from drinking water

2007 ◽  
Vol 55 (8-9) ◽  
pp. 211-217 ◽  
Author(s):  
Jānis Rubulis ◽  
Tālis Juhna
Keyword(s):  
Drinking Water ◽  
Water Supply ◽  
Correlation Coefficient ◽  
Water Distribution ◽  
Water Distribution Network ◽  
Plate Count ◽  
Available Phosphorus ◽  
Water Supply Systems ◽  
Biofilm Development ◽  
Supply Systems

Effect of microbially available phosphorus (MAP) on biofilm development in drinking water systems was investigated at the pilot-scale experiments over 3 years. Completely mixed biofilm reactors Propella® (water detention time 24 h, flow rate 0.25 m s−1, PVC pipe coupons) were used as water distribution network models. Four experimental runs were carried out with water containing different levels of phosphorus which was limiting nutrient for bacterial growth. Positive correlation between MAP in the inlet water and heterotrophic plate count (correlation coefficient 0.95) in biofilm, as well as for the total bacteria number (correlation coefficient 0.71), was observed. However, our experiments showed that removal of phosphorus down to very low levels (below detection limits of chemical method and MAP < 1 μg L−1) was not an efficient strategy to eliminate bacterial regrowth and biofilm formation (<51,00,000 cells/cm2) in drinking water supply systems.

Microbiology, chemistry and biofilm development in a pilot drinking water distribution system with copper and plastic pipes

2004 ◽  
Vol 38 (17) ◽  
pp. 3769-3779 ◽  
Author(s):  
Markku J. Lehtola ◽  
Ilkka T. Miettinen ◽  
Minna M. Keinänen ◽  
Tomi K. Kekki ◽  
Olli Laine ◽  
...  
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Drinking Water Distribution System ◽  
Plastic Pipes ◽  
Drinking Water Distribution ◽  
Biofilm Development

scholarly journals Biofilm bacterial communities and abundance in a full-scale drinking water distribution system in Shanghai

2010 ◽  
Vol 8 (3) ◽  
pp. 593-600 ◽  
Author(s):  
Xiaohui Bai ◽  
Fan Wu ◽  
Binhui Zhou ◽  
Xinghua Zhi
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Bacterial Communities ◽  
Water Distribution ◽  
Water Distribution System ◽  
Full Scale ◽  
Community Diversity ◽  
Plate Count ◽  
Drinking Water Distribution System ◽  
Drinking Water Distribution

Community diversity and abundance of biofilms from a full-scale drinking water distribution system in Shanghai were characterized by denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA sequences and heterotrophic plate count (HPC), respectively. Bacteria affiliated to the Beta- and Gamma-Proteobacteria were dominating in both in-situ and HPC-culturable bacterial communities. Other bacteria present included members of Alphaproteobacteria, Bacteroides, Actinobacteria, Nitrospirae and Firmicutes. Acidovorax, Ralstonia and Acinetobacter were common species in biofilms. Klebsiella pneumoniae and Enterobacter sp. were detected in the local distribution system. Dissolved organic carbon (DOC), residual disinfectant and temperature were the most important factors influencing both bacterial abundance and composition. HPC for biofilm sample was not correlated with its community diversity.

Characteristics of pipe-scale in the pipes of an urban drinking water distribution system in eastern China

2015 ◽  
Vol 16 (3) ◽  
pp. 715-726 ◽  
Author(s):  
Jingqing Liu ◽  
Huanyu Chen ◽  
Qian Huang ◽  
Liping Lou ◽  
Baolan Hu ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Drinking Water ◽  
Cast Iron ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Eastern China ◽  
Galvanized Steel ◽  
Drinking Water Distribution System ◽  
Drinking Water Distribution

Pipes that carry drinking water have gradually aged. Events occurring with increasing frequency, such as substandard water quality in residential taps, red water, and black water, reveal the deterioration of the chemical stability of a drinking water distribution system (DWDS). Pipes in the DWDS serving City S, located in eastern China, were sampled to analyze the concentration and distribution of pollutants in pipe-scale of pipes of different materials, ages and diameters, and the factors (such as materials, age, and diameter) influencing the accumulation of pollutants were also investigated. The quantity of pipe-scale in the most commonly used gray cast iron pipe and ductile cast iron pipe (DN150) was 151.5–195.0 g·m−1 and 7.1–29.4 g·m−1, respectively. The concentration of heavy metals in pipe-scale was positively correlated with the quantity of pipe-scale (R2 = 0.874); the sequence of concentration of metals was Fe > Al > Mn, Zn > Pb, Cu > Cr, Cd. Galvanized steel pipe, with the highest degree of corrosion, had the highest concentration of heavy metals in pipe-scale. The morphology and composition of pipe-scale were substantially influenced by pipe material and age. For example, in the oldest galvanized steel pipe-scale, there was not only a large number of iron compounds but also some zinc composite oxides. In addition to hydrocarbons produced by microbial metabolism, there were microalgae metabolites and exogenous contaminants such as polycyclic aromatic hydrocarbons (PAHs). The concentrations of microbial metabolites increased with increasing service time.

Persistence and decontamination of surrogate radioisotopes in a model drinking water distribution system

2009 ◽  
Vol 43 (20) ◽  
pp. 5005-5014 ◽  
Author(s):  
Jeffrey G. Szabo ◽  
Christopher A. Impellitteri ◽  
Shekar Govindaswamy ◽  
John S. Hall
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Drinking Water Distribution System ◽  
Drinking Water Distribution
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