Hazardous waste reuse, recycle, reclaim

Recycling is the use, reuse or reclamation of wastes after they have been generated. Through recycling and reuse, hazardous wastes are routed into production processes rather than being released to the environment. Reclamation is usually considered to be a part of recycling because it recovers raw material for reuse. The processes used to reclaim useful materials from waste often generate hazardous wastes of their own [16,17,20-23]. 

Spent caustic (3800 tons/year) is sent off-site for recovery of remaining caustic value and naphthenic acids. Most catalysts are recycled for recovery of additional activity or metals. Spent cracking catalyst (6(K) tons/year) is sent to Amoco s Whiting, Indiana, refinery for use as equilibrium catalyst. Spent ultraforming catalyst is returned to metals reclaimers to recover platinum for reuse in new catalyst. Spent desulfurization catalyst and polymer catalyst are nonhazardous and are buried in an on-site landfill. Sludges from the oil/water separator are a listed hazardous waste under RCRA regulations. They are combined with other solid wastes, such... 

One way to minimize hazardous waste is to reuse, recycle, or reclaim materials. For example, there are many processes that require solvents. In some cases the solvent may evaporate. Because regulations prohibit exhausting it to the atmosphere, recovery is necessary. Recovery may involve condensation, adsorption or other means. It must convert to a reusable form. 

The state of Massachusetts has exempted unbroken CRTs from hazardous waste requirements under RCRA. Disposed of broken or crushed CTRs are subject to full hazardous waste requirements. However, intact CRTs that can stiU be reused and those which will be crushed and recycled (i.e., as spent material being reclaimed), will be treated as nonhazardous waste under solid waste regulations. 

Electrolysis is the reaction of either oxidation or reduction taking place at the surface of conductive electrodes immersed in an electrolyte, under the influence of an applied potential. This process is used for reclaiming heavy metals from concentrated aqueous solutions. Application to waste water treatment may be limited because of cost factors. A frequent application is the recovery for recycle or reuse of metals, like copper, from waste streams. Pilot applications include oxidation of cyanide waste and separation of oil-water mixtures. Gaseous emissions may occur and, if they are hazardous and cannot be vented to the atmosphere, further treatment, such as scrubbing, is required. Waste water from the process may also require further treatment. 

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