Costs wetting rates

The cost of the B.E.S.T. system varies depending on waste composition, product requirements, utility costs, flow rate, and volume. Treatment costs, excluding final disposal costs, range from 90 to 280 per wet ton of waste feed (D13798Y, p. 3). 

It is also important to study the interactions of papermaking additives (4) in the paper machine water system some additives act synergisticaHy, so that the performance of each is enhanced by the presence of the other. However, some additives have a negative impact on the performance of other additives, or on other desirable paper properties. Thus, optimization of the addition points and usage rates of the entire additive system is necessary in order to maximize performance of the chemical additives and the paper sheet properties, and to minimize cost and negative interactions both on the paper machine and in the white-water system. This is especially tme as unanticipated additives enter the wet end of the paper machine from recycled furnishes, including coated broke (5). 

The Catalytic Wet Air Oxidation (CWAO) process is capable of converting all organic contaminants ultimately to carbon dioxide and water, and can also remove oxidizable inorganic components such as cyanides and ammonia. The process uses air as the oxidant, which is mixed with the effluent and passed over a catalyst at elevated temperatures and pressures. If complete COD removal is not required, the air rate, temperature and pressure can be reduced, therefore reducing the operating cost. CWAO is particularly cost-effective for effluents that are highly concentrated... 

When absorption is used for VOC control, packed towers are usually more cost effective than impingement-plate towers. However, in certain cases, the impingement-plate design is preferred over packed-tower columns either when internal cooling is desired or where low liquid flow rates would inadequately wet the packing. 

Any material with moisture content above this level creates too much steam for the system to be able to absorb without reducing the rate of feed of wet contaminated materials. According to the vendor, this limitation is economical rather than technical. Fifty percent moisture does not limit the performance of the process, but it increases the energy costs. 

Flats plant. All of the methods studied eliminated the potential for free liquids and excessive amounts of particulate. The methods included (1) addition of a Portland cement/diatomite mixture, (2) solidification using microwave technology, (3) cementation with Portland cement, and (4) polyethylene solidification. All costs were based on a production rate of 178,840 lb of wet sludge per year. The cost reduction (dollars per pound of sludge) relative to Portland cement/diatomite was 11.68 (1993 dollars) for microwave solidification, 10.45 (1993 dollars) for polyethylene solidification, and 8.07 (1993 dollars) for cementation. Table 1 gives a breakdown of these costs (D1353911, p. 8). 

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