AWWA ACE63151

Laboratory, pilot, and field data collected support the theoretical "cupric hydroxide" coppersolubility model. For the short time frames inherent in laboratory and pilot studies of coppersolubility and in initial field monitoring for the LCR from Tier 1 soldered copper sites, cuprichydroxide or a very microcrystalline tenorite should be the dominant solid phase, whereas overtime, the pipe will "age" and tenorite or malachite will form and predominate as the surfacephase. Orthophosphate treatment will initially lower copper levels, when applied in the properpH range. Unlike systems optimizing pH and DIC adjustment, the orthophosphate-treatedsystems tend to see stable copper levels, rather than the "aging" phenomenon. Given enoughtime (years to decades), in similar systems without orthophosphate, the copper levels willprobably eventually drop below what would be achieved with orthophosphate. Systemsemploying orthophosphate see rapid reductions initially, but the stabilization long-term could bedifficult to overcome if there are later issues with more stringent limits on phosphate or copperlevels in wastewater.Compliance monitoring required for the LCR is biased towards sites that may exhibit elevatedlead levels rather than elevated copper levels. Current targeting will likely show that Cu levelswill continue to decline, so the discrepancy between the copper levels covered under LCRmonitoring and that in the locations with potential for highest exposure to copper will increaseover time. Includes 7 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

06/01/2006

Number of Pages:

26

File Size:

1 file , 530 KB