Aqueous Based Cleaners and the Potential Impacts on Industrial Wastewater

摘要

A common Pollution Prevention (P2) strategy in electroplating and metal finishing operations is the replacement of ozone depleting compounds (ODCs) that are typically found in solvent degreasers with aqueous-based products. Although aqueous-based cleaning alternatives eliminate ODCs, they generate new wastewater streams and raise new environmental and facility management issues. For example, wastewater from alkaline cleaning operations typically contains one or more cleaning agents with a pH in the range of 10-12 significant units. From an environmental standpoint, spent cleaning baths may require pH neutralization prior to their discharge to a municipal system. Spent cleaning baths may also contain elevated levels of metals, depending on the substrate being cleaned. From a facility maintenance standpoint, wastewater pumping stations may be necessary to transfer wastewater from the cleaning operation to a facility sewer system. Due to the presence of surface-activating agents (surfactants), spent cleaners may also cause foaming in the facility piping, open tanks, or floor drains thereby causing a nuisance and possibly a safety (slipping) hazard. This paper will present P2 strategies for managing the wastewater pH, TPH, and VOCs associated with new process waste streams. It will also explain the permitting of alternative degreasing and cleaning operations. In addition, facility management issues, such as foaming, the handling of ultra-pure water discharges, and the need for wastewater treatment equipment will be addressed.