Waste minimization process operations

Process operation for waste minimization. Many of the problems associated with waste from process operations can be mitigated if the... 

Process operation for clean process technology. Many of the problems associated with waste from process operations can be mitigated if the process is designed for low inventories of material in the process. This is also compatible with design for inherent safety. Other ways to minimize waste from process operation are7 ... 

Thermal desorption treatment is generally considered to be an alternative to incineration. Thermal desorption operates at much lower temperatures than incineration and keeps the heating systems independent of the wastes, which minimizes off-gas production. The technology can be used as a waste minimization process, isolating and concentrating waste constituents, or as a product recovery process. Thermal desorption can also be used to separate contaminants in mixed waste streams by removing volatile constituents. 

The catalytic vapor-phase oxidation of propylene is generally carried out in a fixed-bed multitube reactor at near atmospheric pressures and elevated temperatures (ca 350°C) molten salt is used for temperature control. Air is commonly used as the oxygen source and steam is added to suppress the formation of flammable gas mixtures. Operation can be single pass or a recycle stream may be employed. Recent interest has focused on improving process efficiency and minimizing process wastes by defining process improvements that use recycle of process gas streams and/or use of new reaction diluents (20-24). 

You should use the material balance information to identify the major sources of waste and pollution, to look for deviations from the norm in waste production, to identify areas of unexplained losses, and to pinpoint operations that contribute to flows that exceed national-, local-, or site-discharge regulations. Also, a good thing to remember is that, from a practical standpoint, process ciency is synonymous with waste minimization. 

California Steel Industries, Inc., located in Fontana, CA, reclaimed wastes to increase profits and address water use issues. The facility, a steel mill, is situated in an area that does not have a ready supply of process water. Also, the offsite recycling facility used to dispose of spent process pickle liquor was soon to become unavailable. As a result of these concerns, the company constructed an onsite recycling facility designed to recover ferrous chloride for resale and to reuse water and hydrogen chloride for use in steel processing operations. Environmental benefits include the recovery and resale of 20 to 25 t/d of ferrous chloride, 13,440 L/d of hydrogen chloride, and 49,200 L/d of water. In addition, corporate liability was minimized because spent liquor was no longer sent to a disposal facility. 

The CAA compliance deadline may cause companies to install simple end-of-pipe emissions controls, instead of pollution prevention process changes. In order to limit this practice and encourage waste minimization, U.S. EPA allows owners and operators of combustion facilities to request a one-year extension to the compliance period in cases where additional time is needed to install pollution prevention and waste minimization measures that reduce the amount of hazardous waste entering combustion feedstreams.16 Requests for a one-year extension must reasonably document that the waste minimization measures could not be installed in time to meet the three-year compliance period. Decisions to grant the extensions will be made by U.S. EPA or authorized state programs. 

Smith R and Petela EA (1992) Waste Minimization in the Process Industries Part 4 Process Operations, Chem Eng, 517 9. 

Assessment of a company s waste minimization needs includes examining the content of and volume of hazardous waste streams it generates, and the processes or operations that generate them. The object of this step is to prioritize the needs of the company, based on environmental risk, liability, and economic criteria. 

Electrolytic treatment technologies have definite advantages over these more common treatment processes. The primary benefit is that chemical change in an electrochemical process is brought about by the ability to add or remove electrons from species to be treated. This eliminates the use of redox agents to treat wastes and also removes the need to treat spent redox streams. Other, equally important, benefits of electrochemical processes include close control of reactions through control of the applied potential or current lower operating temperatures and hence lower costs increased possibility of on-site treatment, especially in small-scale use possible simultaneous use of the anode and cathode for waste minimization and the ability to... 

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