Feed systems treated

A small water treatment system is generally sized to treat water volumes up to at least 0.044 m /s (1 MGD). For small solution-feed systems treating from 9.5 m /d to 0.044 m /s (2500 gpd to 1 MGD), operating and maintenance costs for gas chlorination systems are approximately the same. About 1630 kWh each year is required to run the booster pump and approx 2560 kWh annually is required for the building housing the system, assuming a 58.1-m (625-ft ) building. Maintenance labor cost and material costs for miscellaneous repair of valves, electrical switches, and other equipment replacement cost will be the extra. 

Equipment, operating, and maintenance costs for calcium hypochlorite solution feed systems are similar to those for sodium hypochlorite feed systems. The equipment needed to mix the solution and inject it into the water being treated is the same. 

Chlorine dosage is the amount of chlorine required to oxidize the target substance to be treated (such as water, wastewater, sludge, or septage) plus the desired chlorine residual. The target substance to be treated is termed chlorine demand. Usually the chlorine dosage is computed as mg/L concentration and the chlorine feed system set at the equivalent Ib/d feed rate. 

For SCWO units treating agent hydrolysate only. For SCWO units treating energetics hydrolysate, this pump is replaced by the high-pressure slurry feed system with 11 gpm throughput requirement. 

Similarly, a 4600 m /d Memcor CMF-S system was installed at a 1200 MW coal-fired power plant in the UK when the well water source that provided feed water to the RO-IX high-purity water system was shut down. The sMF system treats surface water and cooling tower blowdown, providing filtered water to the RO-IX deionisation system with turbidity <0.1 NTU, suspended solids at the detection hmit of 1 ppm and SDI <3. The MF membranes were oxidant-resistant PVDF with a pore size of 0.1 pm. 

Most of the figures in current use are apparent values, but in feeding systems in which metabolic nitrogen loss is treated as part of the maintenance nitrogen demand, true rather than apparent coefficients have to be used. 

Many chemicals used in water treatment are delivered and fed in dry form. Table 5-1 lists some common dry treatment chemicals and their common forms. Chemical feed systems measure these chemicals either by volume (volumetric) or by weight (gravimetric). Dry chemicals are sometimes delivered directly to the water. It is far more common, however, to mix the dry chemical with a small volume of water first. The concentrated solution or slurry is then fed into the water, where it is thoroughly mixed. This method is better at dispersing the chemical into the treated water. 

As indicated above, wild rats do not always select calorically balanced diets, especially under laboratory conditions. In attempting to further understand caloric regulating and feeding systems of rats, Piquard et al. (4 have found that a 25% daily calorie glucose infusion into the rat s circulatory system via intracardiac catheter produced an 80% decrease in intake of glucose-treated food. Amino acid and lipid infusion produced decreases in intake of proteins, lipids, and glucids as well. 

In the laboratory, the SLM system treated the 1-L feed solution containing about 525 ppm cobalt in the recycle mode of operation. The SLM removed the cobalt to 0.7 ppm in the treated feed solution in just 15 min (Ho, 2001b, 2002a, 2003). It also concentrated cobalt to about 30,000 ppm in the aqueous strip solution (from the strip solution of 5 M hydrochloric acid preloaded with about 21,250 ppm cobalt). The cobalt flux at the cobalt concentration of about 380 ppm in the feed solution was about 5 g/m /h, which is very high. 

For concentrating the cobalt in the strip solution from an initial concentration of about 3100 ppm to a final concentration of about 100,000 ppm, a relatively high volume ratio of about 8.6 between the organic solution and the strip solution was used (a very high volume ratio of about 260 between the feed solution and the strip solution). Again, the SLM system treated the 40-L feed solution in the recycle mode of operation. Figure 28.7 shows the results. As shown in this figure, the SLM concentrated the cobalt effectively to about 100,000 ppm in the strip solution in about 7 h in the recycle operation (Ho, 2003). 

In the precoat and body feed mode, filter aids allow appHcation of surface filtration to clarification of Hquids, ie, filtration of very dilute suspensions of less than 0.1% by volume, such as those normally treated by deep bed filters or centrifugal clarifiers. Filter aids are used in this mode with pressure filters. A precoat is first formed by passing a suspension of the filter aid through the filter. This is followed by filtration of the feed Hquid, which may have the filter aid mixed with it as body feed in order to improve the permeabiUty of the resulting cake. The proportion of the filter aid to be added as body feed is of the same order as the amount of contaminant soHds in the feed Hquid this limits the appHcation of such systems to low concentrations. Recovery and regeneration of filter aids from the cakes normally is not practiced except in a few very large installations where it might become economical. 

Trickle bed reaction of diol (12) using amine solvents (41) has been found effective for producing PDCHA, and heavy hydrocarbon codistiUation may be used to enhance diamine purification from contaminant monoamines (42). Continuous flow amination of the cycloaUphatic diol in a Hquid ammonia mixed feed gives >90% yields of cycloaUphatic diamine over reduced Co /Ni/Cu catalyst on phosphoric acid-treated alumina at 220°C with to yield a system pressure of 30 MPa (4350 psi) (43). 

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