WASTE STREAMS FROM TRANSPORTABLE TREATMENT SYSTEMS

Waste Streams from Transportable Treatment Systems... 

WASTE STREAMS FROM TRANSPORTABLE TREATMENT SYSTEMS... 

This report supplements an earlier report (NRC, 2001a) that evaluated eight alternative technologies for destruction of the liquid waste streams from two of the U.S. Army s transportable treatment systems for nonstockpile chemical materiel the rapid response system (RRS) and the munitions management device (MMD)This report evaluates the same technologies for the destruction of liquid waste streams produced by a third transportable treatment system, the explosive destruction system (EDS). 

Inclined plate clarification is a traditional separation technology that has been used for decades to remove suspended solids from a liquid stream in various types of systems including traditional precipitation [12]. In the semiconductor industry, the clarifier is commonly used in fluoride waste treatment systems where calcium fluoride precipitate is concentrated prior to dewatering in a press, or in assembly/test operations to separate silicon fines from backgrind operations. The clarifier will concentrate the solid phase of slurry like a UF, but unlike the UF or MF, the clarifier may require the addition of a chemical polymer to facilitate the agglomeration of the suspended solids so that they settle and concentrate. Polymer addition adds another level of complexity to the waste treatment system. The clarifier does not provide a physical barrier to prevent the transport of solids to downstream equipment, so it may be necessary to install a UF or MF downstream of the clarifier to capture extraneous particles or to protect the downstream equipment from clarifier upsets. 

The most important aspect that must be considered when reviewing EDI and RO technologies is that these unit operations never remove the trace metals from the liquid stream [17,18]. Unlike ion-exchange resin, both EDI and RO employ reject streams to transport the now-concentrated contaminants out of the equipment and to another location for treatment or disposition, requiring yet more treatment equipments. This is much different from ion-exchange technology that physically removes the trace metals from the liquid stream. Even with their downside, RO and EDI may be able to play an important role in the waste treatment system if there are water reclamation targets that must be met. 

Membranes, selective to either cation or anion transport, are employed in many of the electrochemical treatment systems already discussed in this chapter. For example, in the cathodic recovery of metals from waste streams, a cation-permeable membrane can prevent the migration of anions such as Cl- from the catholyte to anolyte, where oxidation to CI2 can occur with... 

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