Problems, perceptions and perfection-the role of the drinking water inspectorate in water quality incidents and emergencies

Thompson, K. Clive; Gray, Jon; Jackson, Claire

doi:10.1039/9781847552358-00038

Cited by 1 publication

(1 citation statement)

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“…England has started to implement first draw sampling for bacteria in public buildings, and the initial results do not indicate a significant problem relative to the levels of bacteria detected after flushing (Jackson et al, 2004). This might indicate that the high levels of bacteria cited in this work are extraordinarily rare, occurring only under unusual circumstances of higher temperature, infrequent water use and distance from the treatment plant.…”

Section: Slyme (Cfu/ml)mentioning

confidence: 93%

Unintended Consequences of Chloramine Hit Home

Edwards¹,

Marshall²,

Zhang³

et al. 2005

proc water environ fed

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The known drawbacks of chloramination include nitrification, elastomer decay, and required pretreatment steps for fish culture and dialysis patients. To date, there has been no explicit consideration of adverse consequences of chloramination on property and water quality in buildings. Specifically, the effect of chloramine on re-growth of bacteria during stagnation, plumbing failures and lead leaching are poorly understood.Potential problems with bacterial re-growth can arise in building plumbing systems after chloramines decay and form free ammonia. Autotrophic nitrifying bacteria convert the free ammonia to nitrite and nitrate while creating organic carbon in the form of biomass and soluble microbial products. The levels of organic carbon created by nitrifiers are sufficient to support the growth of heterotrophic (HPC) bacteria. In one water tested with long stagnation times, HPC reached 10 6 -10 7 cfu/ml using chloramines, whereas HPC was 1000x less when chlorine disinfectant was used. The decay of chlorine does not release nutrients for bacterial growth-a significant advantage relative to chloramine in situations with low flow and long detention times. Because the water within home plumbing is rarely sampled for bacteria, the true extent of the problem is not detected by routine distribution system monitoring using flushed samples.A switch to chloramine may increase lead leaching, brass failures and pinhole leaks under at least some circumstances. Of these problems, pinhole leaks and brass failures have the largest potential economic consequence. For instance, a single re-plumb can cost an individual consumer 500x more than the median annual projected cost of the Stage 2 regulation. The adverse public health impacts of mold growth from pinhole leaks, lead leaching and bacterial re-growth deserve consideration. While these problems may eventually prove to be rare events, they have significant consequences for the unfortunate consumers who are impacted. If these events prove to be widespread, alternatives to chloramine will become more attractive despite higher initial cost to utilities.

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Section: Slyme (Cfu/ml)mentioning

confidence: 93%