Wastes from industries are customarily classifiedas liquid wastes, solid wastes, or air pollutants,and often the three are managed by different people or departments.The three separate categories are regulated by separate and distinct bodies of laws and regulations, and historically, public and governmental emphasis has moved from one category to another fromone time period to another. The fact is, however,that the three categories of wastes areclosely interrelated, both as they impact on theenvironment and as they are generated andmanaged by individual industrial facilities.
Solid wastes disposed of in the ground can influence the quality of groundwater and surface waters by way of leachate entering the groundwater and traveling with it through the ground, then entering a surface water bodywith groundwater recharge. Volatile organics in that recharge water can contaminate the air. Air pollutants can fall out to become surface water or groundwater pollutants, and water pollutants can infiltrate into the ground or volatilize into the air.
Waste treatment processes can also transfersubstances from one of the three waste categoriesto one or both of the others. Air pollutantscan be removed from an air discharge by meansof a water solution scrubber. The waste scrubbersolution must then be managed to enable itto be discarded within compliance with applicablewater regulations. Airborne particulatescan be removed from an air discharge using abag house, thus creating a solid waste to bemanaged. On still a third level, waste treatmentor disposal systems themselves can directlyimpact on the quality of air, water, or ground.Activated sludge aeration tanks are very effectivein causing volatilization of substancesfrom wastewater. Failed landfills can be potentpolluters of both groundwater and surfacewater.
The total spectrum of industrial wastes, then,must be managed as substances resulting froma system of interrelated activities. Materialsbalances must be tracked, and overall costeffectiveness must be kept in focus.