Nitrification in Drinking Water Systems

Nitrification in Premise Plumbing: Role of Phosphate, pH and Pipe Corrosion

“…Copper and brass plumbing materials invariably leach copper to water supplies at concentrations dependent on numerous factors including pipe age and water chemistry. In the range of copper known to occur in water of premise plumbing systems (0-5000 ppb), slight increases in copper (≈ 1-10 ppb) from corrosion could stimulate nitrification, whereas higher levels of copper (above about 100 ppb) could inhibit nitrification (11). Corrosion of copper and brass plumbing used in many buildings may therefore be preventing degradation of water quality from nitrification in at least some instances, and well-intentioned actions to minimize copper leaching to water (increasing pH, adding orthophosphate corrosion inhibitors or using only plastic pipes) might increase the likelihood of establishing nitrifiers.…”

“…A recent literature review predicted that the incidence of nitrification in premise plumbing systems would be at least partly controlled by water chemistry and materials usage (11). Copper and brass plumbing materials invariably leach copper to water supplies at concentrations dependent on numerous factors including pipe age and water chemistry.…”

“…Zinc in galvanized pipe has also been reported to convert nitrite to ammonia under drinking water conditions (16). It is, therefore, possible that nitrifier growth on lead and zinc alloy surfaces would be favored relative to more inert surfaces such as polyvinyl chloride (PVC), exacerbating nitrification occurrence and undermining efforts to mitigate lead contamination of water supplies from pH adjustment (9,11).…”

“…The ammonia formed via chloramine decay can support autotrophic microbial nitrification. Organic carbon and acid produced via nitrification can stimulate growth of heterotrophic bacteria, contribute to loss of disinfectant, and also create problems with lead and copper contamination from corrosion of premise plumbing systems (5)(6)(7)(8)(9)(10)(11)(12). Nitrification also creates nitrite which has a relatively low maximum contaminant level (MCL) of 1 mg/L-N. Prevention of nitrification is therefore deemed to have desirable public health consequences.…”

Conventional Media Filtration with Biological Activities

“…The effectiveness of biological ammonia oxidation treatment to reduce source water ammonia levels is dependent on a number of source water and engineering design factors including temperature, dissolved oxygen, TOC, pH, biomass quantity and population, media type, and surface area, as well as hydraulic loading rate and contact time (Zhang et al 2009). Factors affecting nitrification occurrence, nitrification impacts on water quality and corrosion, and nitrification monitoring and control methods were reviewed previously (Zhang et al 2009). Arrhenius coefficient was 1.12 without acclimation and 1.06 with acclimation (Andersson et al 2001).…”