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Developing effluent limitations for hardness‐based metals considering dynamic variability of effluent and receiving water hardness
Author(s) -
Laputz Adam,
Saiz Steve
Publication year - 2009
Publication title -
journal ‐ american water works association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.466
H-Index - 74
eISSN - 1551-8833
pISSN - 0003-150X
DOI - 10.1002/j.1551-8833.2009.tb09843.x
Subject(s) - effluent , environmental science , water quality , hard water , zinc , chromium , environmental engineering , metallurgy , materials science , chemistry , ecology , organic chemistry , biology
Effluent hardness and flow data from two publicly owned treatment plants were superimposed onto 15 receiving water data sets to investigate the effect of hardness variability on implementation of the US Environmental Protection Agency—s (2000) hardness‐dependent water quality criteria (e.g., metals). A mass balance model was used to compute metals water quality criteria for the hardness variability in effluent and receiving water mixtures. Random subsets of the observations were used to estimate the sample size required to develop protective metals criteria and effluent limitations. For the 30 effluent and receiving water scenarios, protective chronic cadmium, copper, chromium, nickel, and zinc limitations can be developed using the minimum observed effluent hardness value; however, large hardness sample sizes (n > 24) were required in many cases. More sophisticated methods and comprehensive data sets are required to develop protective lead and silver limitations, although some simplified relationships are described. Criteria developed using the mass balance model are compared with criteria developed using methods proposed by Emerick et al (2006).