Treatment System Components

The basic premise of CMP waste treatment is to remove the target trace metals (Cu, W, Ta, etc.). The primary challenges that add complexity to the CMP waste treatment systems is the presence of the suspended solids, organics added to stabilize metal ions that may be counteractive to some of the treatment chemistries, and oxidizers in the slurry waste. 

The basic components of a CMP waste treatment system are as follows  

Depending on the characteristics of the CMP waste and the environmental discharge permits negotiated with the local authorities, some steps (such as control of suspended solids removal) may not be required, but every CMP waste treatment system requires a method for removing the trace metals. The rest of this chapter will discuss each aspect of the waste treatment system and the pros and cons of combining the unit operations to create a functional treatment system. 

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The ozone molecule can react with incompatible materials, such as treatment system components. 

Network Distributed Process Control System (links treatment system components to central monitor station)... 

Coal Slurries - Two component treatments prove to be effective on a commercial scale for coal slurry flocculation. The use of encapsulated floccuiant suspended in a counter charged floccuiant provides the robusmess of traditional dual component systems, but with additional performance advantages, which include reduction in filter cake moisture content and an increased throughput rate. Figure 5 illustrates the typical filter cake moisture content obtained by a conventional treatment system compared to the encapsulated treatment system using coal tailings as the substrate. 

Microparticulate Systems - Although dual combination treatment systems comprising microparticles and flocculants have been used in the paper industry since the 1980s, it is only recently that there has been a general trend for paper mills to switch from conventional single component systems to dual systems. 

About 100 gal of process wastewater is typically generated from 1 t of coke produced.15 These wastewaters from byproduct coke making contain high levels of oil and grease, ammonia nitrogen, sulfides, cyanides, thiocyanates, phenols, benzenes, toluene, xylene, other aromatic volatile components, and polynuclear aromatic compounds. They may also contain toxic metals such as antimony, arsenic, selenium, and zinc. Water-to-air transfer of pollutants may take place due to the escape of volatile pollutants from open equalization and storage tanks and other wastewater treatment systems in the plant. 

These factors may influence the specific aboveground treatment technology that is selected, the possible need for multiple aboveground treatment processes (treatment trains), and the need for pretreatment of groundwater or posttreatment of off-gas. Also, as with the extraction component, the presence of an active source area may result in the need for long-term operation of aboveground treatment systems. 

The technology uses patented equipment to directly inject treatment compounds into sediments. The equipment can be mounted on boats, barges, or floats and can be propelled by boat, tug, or a winch from shore. A key system component is a specially designed boom arm that is dragged behind the vessel. The boom arm contains a series of nozzles, tines, and injection ports. 

Capital costs of gas treatment system include purchase cost of system components and fabrication costs. 

While minimizing blowdown volumes can be quite effective in reducing waste, removing the hazardous metals component of the waste stream can have a more dramatic effect on reducing the impact of the blowdown on the environment. Chromate based corrosion inhibitors have historically been the mainstay of cooling water treatment systems. But in recent years, some plants have elected to use nonchromate inhibitors in order to reduce the potential environmental problems associated with chromates. Types of nonchromate inhibitors that have proved useful and that have in some situations performed as well as chromates include (Roti 1985) ... 

The entire system is based on a tiered approach where three layers of technology are integrated into the overall treatment system, as illustrated in Chart 2. First, a distributed process control system is network linked to the various component subunits of the waste management system such as pH control, ion-exchange control, tank level control, etc. Next, are the recovery/treatment processes themselves. The final tier is a monitoring system which controls both the performance of the treatment systems and the discharge assurance of the plant effluent... 

Water filters are used in various locations in water treatment systems for two basic purposes removal of undissolved solids, some of which are added to the water by various components of the water treatment system, and removal of... 

Conclusions and recommendations is the next section. Here, a statement is made regarding the validation status of the water or air treatment system and the possible need for additional validation studies focusing on some aspect or component of the system. 

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