Pipe Scales and Biofilms in Drinking-Water Distribution Systems: Undermining Finished Water Quality

Makris, Konstantinos C.; Andra, Syam S.; Botsaris, George

doi:10.1080/10643389.2013.790746

Cited by 103 publications

(45 citation statements)

References 191 publications

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“…Pipe scales and biofilms coexist in UDWDS serving as sources of chemical release to finished water through poorly understood mechanisms, posing an unaccounted so far risk to consumer health. Pipe-anchored biofilms may also act as sources of microbial release to finished water or as scavengers of added disinfectant chlorine (Edwards et al, 2009;Makris et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…As a result, residual chlorine levels within the pipe network of an urban center may not be homogeneously distributed across all network points. We hypothesized that spatially resolved, geocoded pipe characteristics and leaking incidences linked with biofilm-induced corrosion events (Makris et al, 2013) and an enhanced DBP formation (Wang et al, 2013b) could improve our understanding of chlorine consumption dynamics. Studies have already demonstrated the influence of water residence time on chlorine demand and the subsequent increase in planktonic microbial counts within the UDWDS (Mahto and Goel, 2008;Srinivasan et al, 2008;Shamsaei et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

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Variability of Tap Water Residual Chlorine and Microbial Counts at Spatially Resolved Points of Use

PieriPanayiota

Andra

Charisiadis

et al. 2014

Environmental Engineering Science

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Balancing the risk between microbial and disinfection by-product exposures in potable water through optimization of disinfectant (chlorine) dosing often proves a difficult task in aging urban drinking-water distribution systems (UDWDS). We hypothesized that geocoded pipe characteristics could improve our understanding of chlorine consumption in a city of a geographic region (Eastern Mediterranean) that has been poorly studied. The main objectives of this study were to (1) determine the UDWDS characteristics (household distance from chlorination tank and pipe leaks) that could explain the spatial variability of residual free chlorine, and (2) investigate the association between water microbial counts and residual chlorine in two areas with contrasting pipe network characteristics (low-risk and high-risk; LRA and HRA). We collected water samples from 150 households in two areas of Nicosia, Cyprus, during winter (air temperatures 0-15°C). Household addresses were linked with geocoded pipe network data, on-site residual chlorine levels, trihalomethanes (THM), and microbiological measurements. No significant difference (p > 0.05) in the average free residual chlorine levels was observed between the two areas, despite their documented differences in water age. However, the mean THM concentration in HRA (76 lg/L) was significantly (p < 0.001) higher than that in LRA (56 lg/L). Each household's distance from the chlorination tank could explain up to 29% of the variability in free residual chlorine levels for LRA, after adjusting for confounders, such as, total bacterial count (TBC) 22°C/37°C, THM, and pipe leaking incidences; this strength of association did not hold for HRA. Pooling data from both areas, a significant (p < 0.05) multivariate model of residual chlorine was constructed, with TBC 37°C being the only significant predictor. Water boards with historically low water microbial counts could apply area-specific residual chlorine monitoring and management schemes within their UDWDS to ensure minimization of total THM formation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Variability of Tap Water Residual Chlorine and Microbial Counts at Spatially Resolved Points of Use

PieriPanayiota

Andra

Charisiadis

et al. 2014

Environmental Engineering Science

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“…This may be particular important for regulatory agencies dealing with the huge number of contaminants present in the 98/83 EU directive for drinking water. In light of recent reports emphasizing on the episodic release of inorganic contaminants into water from pipe scales Schock 2005;Makris et al 2013), it is warranted that chemical mixture approaches are developed. From this study, it appeared that trace elements with belonging to the same group in the periodic chart such as As and Sb (p<0.0001), and toxic metals with similar properties such as Zn and Cd (p<0.0001) and Cu and Ni (p<0.0001) exhibited significant positive correlations as distinct pairs (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Meanwhile, incidences of drinking water quality compromise in the aged pipe distribution systems and associated reflections on human health occurred (Edwards et al 2009) and continue worldwide. Hence, an emerging focus on the fate of trace inorganic contaminants referred hereby as trace elements within UDWDS is urgently needed to better understand related processes, mechanisms, and factors that influence contaminant accumulation and release from pipe scales/biofilm conglomerates Makris et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Co-occurrence profiles of trace elements in potable water systems: a case study

Andra

Makris

Charisiadis

et al. 2014

Environ Monit Assess

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Potable water samples (N = 74) from 19 zip code locations in a region of Greece were profiled for 13 trace elements composition using inductively coupled plasma mass spectrometry. The primary objective was to monitor the drinking water quality, while the primary focus was to find novel associations in trace elements occurrence that may further shed light on common links in their occurrence and fate in the pipe scales and corrosion products observed in urban drinking water distribution systems. Except for arsenic at two locations and in six samples, rest of the analyzed elements was below maximum contaminant levels, for which regulatory values are available. Further, we attempted to hierarchically cluster trace elements based on their covariances resulting in two groups; one with arsenic, antimony, zinc, cadmium, and copper and the second with the rest of the elements. The grouping trends were partially explained by elements' similar chemical activities in water, underscoring their potential for co-accumulation and co-mobilization phenomena from pipe scales into finished water. Profiling patterns of trace elements in finished water could be indicative of their load on pipe scales and corrosion products, with a corresponding risk of episodic contaminant release. Speculation was made on the role of disinfectants and disinfection byproducts in mobilizing chemically similar trace elements of human health interest from pipe scales to tap water. It is warranted that further studies may eventually prove useful to water regulators from incorporating the acquired knowledge in the drinking water safety plans.

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“…While the hydraulic mobilisation of iron and manganese deposits has been long known to result in discoloured water, the presence of discoloured water can also be due to other processes such as biofilm mobilisation or chemical interactions between pipe materials and water acidity [7][8][9][10][11]. Discolouration has been shown to significantly vary even between different parts of the same water distribution network and yet is still similarly experienced throughout different countries regardless of widely-varying factors between their Water Distribution Systems (WDS) [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Data-Driven Study of Discolouration Material Mobilisation in Trunk Mains

Meyers

Kapelan

Keedwell

2017

Water

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Abstract:It has been shown that sufficiently high velocities can cause the mobilisation of discolouration material in water distribution systems. However, how much typical hydraulic conditions affect the mobilisation of discolouration material has yet to be thoroughly investigated. In this paper, results are presented from real turbidity and flow observations collected from three U.K. trunk main networks over a period of two years and 11 months. A methodology is presented that determines whether discolouration material has been mobilised by hydraulic forces and the origin of that material. The methodology found that the majority of turbidity observations over 1 Nephelometric Turbidity Units (NTU) could be linked to a preceding hydraulic force that exceeded an upstream pipe's hydraulically preconditioned state. The findings presented in this paper show the potential in proactively managing the hydraulic profile to reduce discolouration risk and improve customer service.

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Pipe Scales and Biofilms in Drinking-Water Distribution Systems: Undermining Finished Water Quality

Cited by 103 publications

References 191 publications

Variability of Tap Water Residual Chlorine and Microbial Counts at Spatially Resolved Points of Use

Variability of Tap Water Residual Chlorine and Microbial Counts at Spatially Resolved Points of Use

Co-occurrence profiles of trace elements in potable water systems: a case study

Data-Driven Study of Discolouration Material Mobilisation in Trunk Mains

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