Metal finishing effluent discharges

Monitoring Requirements of Metal Finishing Effluent Discharges. 380... 

U.S. CODE OF FEDERAL REGULATIONS FOR METAL FINISHING EFFLUENT DISCHARGE MANAGEMENT... 

This section introduces the U.S. Code of Federal Regulations (CFR) Title 40, Part 433 (40 CFR part 433) for effluent discharge management of metal finishing point source category. 

In some cases, effluent limitations and standards for the following industrial categories may be effective and applicable to wastewater discharges from the metal finishing operations listed above. In such cases, the 40 CFR part 433 limits shall not apply and the following regulations shall apply ... 

Historically, refinery cyanide control was not a concern because cyanide levels in refinery effluent were usually much lower than those in wastewaters from metal finishing and plating industries. Regulatory agencies have now established new and more stringent cyanide effluent limits for most wastewater discharges. One example is the cyanide effluent limit of 0.025 mg/L (as total cyanide) in the San Francisco Bay imposed by the California Water Resources Control Board [60]. 

Conventional chemical treatment of metal finishing wastes will usually produce clarified effluent acceptable for discharge however, in those applications where it is desirable or necessary to recover the clarified rinse water for re-use, the technologies are utilized to purify or "desalt" the effluent for re-use. 

Nickel-free environment-friendly seals are fast becoming the seal of choice where clear or electrolytically colored parts are concerned. Because there is nothing to leach, these mid-temperature seals accomplish hydration of the oxide without the use of the heavy metal ions. When the seals become contaminated or are no longer effective, they can be discharged to the sewer without subsequent treatment (except possible pH adjustment). This offers the finisher a safer alternative to the effluent treating necessary with heavy metal containing seals. 

Industrial effluent. Authorized discharges from chemical, concrete, food, forest, gravel washing, metal fabricating and finishing, port industries, and other industrial sectors in the Lower Fraser River Basin total almost 300,000 m /day, 90... 

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