Contents 0 TECHNOLOGY WASTE WATER

Many site-specific characteristics have an impact on vitrification technologies. One critical aspect of any thermal technology is the water content of the waste. Water dilutes feed material, requires energy to drive off, and physically limits the feed rate of waste. Feed preparation is another variable, which differs with the technology and with site-specific characteristics. Many estimates do not take into account site preparation and waste disposal costs. Only complete treatment life-cycle assessments can provide reliable comparison data, and such studies are, by definition, highly site and waste specific (D18248T, p. 55). 

Many site-specific characteristics have an impact on vitrification technologies. One critical aspect of any thermal technology is the water content of the waste. Water dilutes feed material. 

Because water can be considered as one of the most benign solvents available, together with its solvation powers at high temperature, its applicability for a variety of wastes is tremendous. However, based on the current developments of the process, its applicability remains limited to pumpable waste streams. In addition, it is generally understood that the waste streams with organic content in the 1-20 wt.% range is most suitable for this technology. Waste streams with 100 wt.% can be treated with appropriate dilution. However, the cost for the dilution may add prohibitively to the total cost. 

Conductometry. This rather unspecific method is used most frequently in the control of industrial chemical processes the output controls of particular technological processes are important in the pollution control, mainly of flowing waters and the atmosphere. The very low conductivity of pure water permits this method to be used to track the total content of pollutants, which is frequently sufficient. A typical example of the use of conductometric methods for environmental protection are analyzers of detergents in waste waters, of concentration of synthetic fertilizers in irrigation waters, of the quality of potable waters, etc. In addition to classical conductometric methods, high frequency methods (oscillometry) are also used, in which the electrode system is not in direct contact with the sample. 

Inorganic dissolved substances, i. e. salts, are measured as increased conductivity. Salts are also detrimental to the process performance and potentially for the paper properties. Electrolytes reduce the swelHng potential of fibers and chloride especially leads to corrosion of machine parts [4]. The content of detrimental substances in paper miU water circuit systems depends on the input of raw materials, on the output by bleeding through waste water disposal as well as by the degree of transfer to the final paper, on the loop design, and on the presence of kidney technologies in the miU. 

Waste treatment technologies for incineration and landfill of PVC are present in the ecoinvent database. The material specific burdens for the waste treatment are calculated by a supporting spreadsheet. Necessary data for the calculation of the burden are, e.g. element composition, water content, energy content, degradability in landfill, etc. Note that the Ecoinvent waste management model estimates emissions based on the element composition and some general characteristics of the materials (like degradability). Detailed characteristics, like the mobility of DEHP from PVC, are not taken into account. Therefore additional assumptions have been made for the emission of DEHP from landfill of PVC. 

Wastes with water content greater than 85% increase the energy costs of the process. Some problems have been noted with phase separations in the final waste form. The technology cannot treat gases or iodine. Mercury is difficult to incorporate. There are concentration limits for some elements in a silicate glass final waste form. Phosphate glass final waste forms can incorporate greater concentrations of some metal oxides, chlorine salts, and mercury in some cases. 

The Terrazyme phase segregation technology was developed to be a volume reduction system for use on wastes with high water contents. It is a chemically enhanced, mechanical separation process for segregating waste into a liquid and a solid phase. 

The vegetation used to extract toxic metals may pose a risk to animals that consume these plants. Animal consumption of process plants could also result in harmful metals working their way up the food chain. Hyperaccumulation is a much slower process than most chemical and physical technologies, and its performance is typically measured in months or years. Technology effectiveness is limited by root growth thus, wastes must be relatively close to the surface. In addition, the toxicity of the targeted contaminants and other site-specific characteristics such as pH, soil characteristics, nutrient content, and water availability can impact technology performance. 

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