AWWA WQTC62528

The impact of nutrients on growth of nitrifying bacteria is investigated under extremecircumstances encountered in premise plumbing. Growth of nitrifying bacteria used inthis study could not be maintained long-term on glass pipes during days of stagnationbetween introduction of freshwater. However, if pieces of concrete were present,growth was greatly stimulated. With continuous inoculation, nitrifying bacteria couldnot oxidize ammonia in stainless steel and pure lead pipes for a month of exposure, butcould do so thereafter. Similar effects were observed after three months for galvanizediron but not in copper pipe after five months. Studies of nitrification in glass piperevealed that zinc levels above 150 ppb and copper levels above 500 ppb inhibitednitrification. Phosphorus levels below 1 ppm, calcium below 0.27 ppm and potassiumbelow 3.89 ppm were associated with lower levels of nitrification. Other elementsincluding magnesium, molybdenum, cobalt, manganese, chelated iron, iron, nickel,chromium, tin, lead, aluminum did not have a strong effect on nitrification at levelsencountered in drinking water. Control of nutrients including phosphate could be animportant strategy to prevention of nitrification. Includes 22 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2005

Number of Pages:

16

File Size:

1 file , 400 KB