Hazardous wastes are defined as wastes that pose a potential hazard to living organisms for one or more of the following reasons: a) wastes are nondegradable, b) effects can be magnified by the environment, c) can be lethal, d) cause detrimental cumulative effects. Hazardous wasted can be in Liquid, sludge or solid form. Numerous treatments, methods of modifying the chemical and/or physical characteristics or composition of a waste are available. Solidification and stabilization technology is used to treat a wide variety of wastes. Solidification is the process of producing a monolithic structure by adding some sort of additive. Stabilization is the introduction of additives to cause a chemical reaction to make the waste less leachable. Encapsulation is the isolation of waste by coating the waste particles with an additive. The stabilization, solidification, encapsulation and/or neutralization of hazardous waste material requires accurate proportioning of the various additives with the contaminated material. Plant configuration, accuracy and reliability in conjunction with trained, qualified personnel are basic to satisfying the stringent requirements of this work.
Gears, Inc. and Pyramid Environmental Inc. utilize the Aran continuous mixing plant that has proven to be very effective due to the plant’s mobility, self-containment and high degree of accuracy. The Aran plant is a continuous feed, volumetric, computer recorded plant. During calibration, a relationship between belt speed and throughput, in tons per hour, is established.
This relationship is linear and is calculated and recorded by the Contrec model 405 flow computer. This microprocessor-based instrument is fully programmable. All calculation constants are set via the front panel switches and stored permanently in a non-volatile memory. The flow computer records the number of pulses coming from the transducer in total tons. The plant’s transducer is a proximate detector located on the wheel’s shaft of the additive feed belt.
The Aran plant is used to blend contaminated soil and the selected additive. Pre-screened soil is loaded into the plant’s aggregate hopper with either a front end loader or a conveyor. The soil is fed to the twin shaft mixing chamber on a belt. The soil flow rate is controlled hydraulically by the operator. The additive is stored in the plant’s 1,180 cubic foot silo and fed to the mixing chamber via a cleated belt which is hydraulic driven via a chain reduction. The Aran ABFC Series additive metering feeders are recognized throughout the industry for their excellent uniformity. Water, if required, is stored in the 2,250 gallon on board storage tank and metered by means of hydraulically driven constant displacement pumps which have speed variation via a flow control valve.
The Aran plant is the only mixing plant which is fast enough for big projects, compact enough for confined spaces, quiet enough for urban areas and powerful enough for cohesive materials. It is versatile enough to handle unusual materials, highly accurate and consistent in metering- thereby minimizing additive costs and mixes with superior homogeneity.