Pollution control in the fatty acid industry

Operations of the fatty acid industry create waste‐waters, emissions to the air, and solid wastes which have the potential of insulting the quality of the environment in a number of wasy. Some of the controversy and the problems that are current in the national environmental effort are discussed. As to the fatty acid industry prospects, some attention may come to the industry if toxics are found to be in the industry's wastewaters. New air emissions permit will be difficult if not impossible to obtain. Long delays and expensive data gathering will be involved. Disposal of solid waste classified as hazardous materials will become extremely costly and involve much paperwork. Wastewaters can originate from any of the process steps: spills and tank bottoms from receiving and storage, foots from alkaline extraction pretreatment, condensate from pressure reduction after fat splitting, condensing water and condensate from fatty acid distillation, and condensing water from glycerine evaporation and distillation. The organic matter in the wastes is biologically degradable so one pollutional effect is reduction of the oxygen level in receiving streams. Oil not in soluble or finely dispersed state is objectionable for the additional reason that it forms slicks or films in the water surface. Fatty acids in soluble forms are toxic to fish in fairly low concentrations. Heavy metal catalysts used for fat splitting or hydrogenation such as zinc are objectionable at trace levels. Source control methods include good operator attention to minimize avoidable losses, optimum recovery of fatty acids and oil in recovery steps, mist eliminators and entrainment separators in distillation and evaporator vapor conduits, and use of indirect condensers in place of direct spray condensers. Treatment of wastewaters includes removal of floatable fat and fatty acids by gravity settling. The residual wastewaters so pretreated are susceptible to treatment processes using bacteria for their degradation. Most fatty acid producers discharge the wastewater to municipal systems in which they receive biological treatment along with residential sewage. Air emissions are minimal for the standard criteria of particulates, organics, etc., because of the low vapor pressure of the materials involved. Odor is not subject to federal legislation, and local regulations and circumstances of concern vary. Odors originate from storage tank vents, from noncondensables vented to the atmosphere from condensers on pressure‐relief operations, and from stills. Cooling tower recirculating systems may release odors condensed in the condensing sprays, or odors may be generated from bacteria growth in the system. Odors are controlled by wet scrubbers on off gases and by conveying the gases (air) to the boiler as air supply. This practice incinerates the odor‐producing compounds. Solid wastes include spent clay used in pretreatment and foots from glycerine stills. Deposit in sanitary landfills is the usual disposal. If solid wastes contain much metal catalysts, their disposal must be to special sites approved for hazardous waste materials.