Ultimate sludge disposal

The equipment is well known and so only a few of its features for refining industry use will be pointed out. 

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Sludge or solid waste is unavoidably produced in the treatment of water containing suspended solids. There are, however different technologies that we can select among that will indeed concentrate these solids, and thereby reduce the volumes that we ultimately must dispose of. In addition, some sludge can be stabilized and treated, which can impart a low, but none-the-less marketable value to this waste. These technologies and practices do indeed constitute pollution prevention and waste minimization programs within water treatment plant operations, and they can... 

The solids that result from wastewater treatment may contain concentrated levels of contaminants that were originally contained in the wastewater. A great deal of concern must be directed to the proper disposal of these solids to protect environmental considerations. Failure to do this may result in a mere shifting of the original pollutants in the waste stream to the fmal disposal site where they may again become free to contaminate the environment and possibly place the public at risk. A more reasonable approach to ultimate solids disposal is to view the sludge... 

Settled sludge is a by-product of wastewater treatment. It usually contains 95-99.5% water as well as solids and dissolved substances that were present in the wastewater or were added during wastewater treatment processing. Usually these wastewater solids are further dewatered to improve their characteristics prior to ultimate use/disposal. 

Ultimately, disposal of the sludge is lequireATwo of the main alternatives for sludge disposal are land spreading and incineration. 

Sludge Management. Sludge management represents about half of wastewater treatment operation and maintenance (O M) costs. The ultimate disposal of sludges produced by either pretreatment or joint treatment operations is an important consideration. The POTW must be aware of effects on the environment that may result from sludge disposal. Pretreatment facilities normally... 

Sludge Stabilization. Organic sludges need to be stabilized before ultimate disposal except in the case of incineration. This is usually achieved by either aerobic or anaerobic digestion. In aerobic digestion, the degradable volatile soHds are Hquefted and oxidized to CO2 and H2O. In anaerobic digestion the soHds are Hquefted and fermented to CH and CO2. 

Because of the wide variability in sludge characteristics and the variation in acceptability of treated sludges for ultimate disposal (this is a function of the location and characteristics of the ultimate disposal site), it is impossible to prescribe any particular sludge-management plan. In the sections below, general performance of individual sludge-treatment processes and operations is presented. 

Disposal The final func tional element in the sohd-waste-management system is disposal. Disposal is the ultimate fate of all solid wastes, whether they are wastes collected and transported direc tly to a landfQl site, semisolid wastes (sludge) from industrial treatment plants and air-pollution-control devices, incinerator residue, compost, or other substances from various solid-waste processing plants that are of no further use. 

Table 28-2 lists some of the currently used pretreatments and ultimate disposal methods for hazardous wastes (6). Pretreatment refers almost entirely to thickening or dewatering processes for liquids or sludges. This process not only reduces the volume of the waste but also allows easier handling and transport. 

What would be the ultimate disposal of dry material collected by an ESP at a cement plant kiln outlet What would be the ultimate disposal of wet sludge from a scrubber on a cement plant kiln outlet ... 

Corrective Action Application In Massachusetts, a municipal wastewater treatment plant receives a number of wastestreams containing heavy metals from local industries. When tested, the dewatered sludge failed the EP toxicity test. In order to permit landfill disposal of the sludge, solidification processes were examined. A soluble, silicate-based system, developed by Chemfix, was ultimately selected which produced a product whose leachate passed the EP toxicity test (Sullivan, 1984). 

Ultimately, the sludge must all be disposed of. The way in which this is done depends on the quality of the sludge, and determines how it needs to be treated. The most desirable final fate for these solids would be for beneficial use in agriculture, since the material has organic matter to act as a soil... 

Ultimate analysis-an analysis to determine the amounts of basic feed constituents. These constituents are moisture, oxygen, carbon, hydro- gen, sulfur, nitrogen, and ash. In addition, it is typical to determine chloride and other elements that may contribute to air emissions or ash- disposal problems. Once the ultimate analysis has been completed, Dulong s formula can be used to estimate the heating value of the sludge, Dulong s formula is ... 

As already noted, all the sludge produced at a treatment plant (whether it be sewage or industrial in origin) must be disposed of ultimately. Treatment processes such as have been described may reduce its volume or so change its character as to facilitate its disposal, but still leave a residue which in most cases must be removed from the plant site. Like the liquid effluent from the treatment plant, there are two broad methods for the disposal of sludge ... 

These methods are used when the organic concentration of the feed exceeds 1% of the total32 and sometimes when it is less. This may occur in the preparation of the sludge for ultimate disposal or in various food-processing industries. The reaction rates are lower and the systems are more sensitive to toxic material than for aerobic systems. The total detention time ranges from 4 to 60 days. 

Industrial treatment plants may not be able to use their biological sludges as fertilizer or spread them on nearby fields if certain substances are present. They may be forced to dry and bum them instead. In some cases, as when heavy metals are present, they may have no recourse but to recover them or use deep-well or ocean-dumping methods. Often anaerobic digestors are used to reduce the amount of sludge and hence the size of subsequent equipment or the cost of ultimate disposal. 

Page AL. 1974. Fate and effects of trace elements in sewage sludge when applied to agricultural lands. A literature review study. Ultimate Disposal Research Program. Cincinnati, OH US Environmental Protection Agency, Office of Research and Development. NTIS PB-231 171. 

Solid wastes represent the ultimate in mill residues and include the accumulated refuse of the mill and the sludges from primary and secondary effluent treatment. There is difficulty in removing water from the secondary sludge the primary and secondary sludges often are mixed to aid in water removal, which is important if the sludge is to be incinerated for disposal. The sludges from pulp and paper mills are handled mostly as landfill, and sometimes, if not toxic, they are spread for agricultural purposes. 

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