Disposal of Industrial and Domestic Wastes Land and Sea Alternatives (1984) / Chapter Skim
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5. CASE STUDY A: REPORT OF THE PANEL ON SEWAGE SLUDGE
5. CASE STUDY A: REPORT OF THE PANEL ON SEWAGE SLUDGE
Pages 146-185
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From page 146... ...
Page, University of California, Riverside 5.1 INTRODUCTION 5.1.1 Why Must Wastewater Sludges Be Studied? For every 1000 cubic meters of wastewater received in a wastewater treatment plant there will be of the order of 60 to 320 kilograms dry weight of solids that must be disposed of.
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From page 147... ...
Given this fact, a basic question arises: Is the scientific-technical information now available about sludge disposal sufficient for making decisions within some reasonable risk factor? Similarly, the data a decision maker must deal with in regard to sludge disposal must include public perceptions of what is safe and suitable.
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From page 149... ...
Because of the differences in the characteristics of communities, the composition of sludge can vary considerably from city to city. For example City of Los Angeles wastewaters receive 12 percent industrialcommercial waste, while Los Angeles County Sanitation Districts wastewaters have a 30-35 percent industrial flow.
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From page 150... ...
Section 5.3 outlines available sludge disposal/reuse options. Section 5.4 presents a discussion of site-specific and local considerations that must be recognized in a multimedia assessment.
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From page 154... ...
5.2.3 Sludge Conversion In the past few years, most major cities have experienced considerable difficulty in obtaining new sites for sewage sludge disposal. Consequently, a variety of methods for stabilizing sludge or converting it to other products have been explored.
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From page 155... ...
A variety of thermal conversion processes is also available. These processes, which result in the conversion of sludge to gases and a residual ash, will be considered in a separate section, since air emissions and land disposal of an ash with concentrated trace contaminants introduce other disposal problems.
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From page 156... ...
Poppua and Bolotina (1963) state: "The most essential advantage of this process is the sanitary quality of the TABLE 5.1 Reduction in Bacterial Densities in Mesophili and Thermophilic Anaerobic Digestion (20-Day Detention)
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From page 161... ...
. It is considered improbable that ruminant animals would be at risk when foraging on sludge-treated soils, however, since only a few plant species accumulate Co and the concentration of Co in sludge is low.
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From page 162... ...
The effect of undesirable concentrations of xenobiotic contaminants is considered in Chapter 4 on biological concerns since much of the ongoing work has been carried on by biological scientists. 5.2.5.3 Selection of Disposal/Utilization Sites The same hydrological and geological considerations that apply to land disposal of other contaminant containing wastes must be taken into account in selecting a site for sludge disposal.
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From page 163... ...
5.3.1 Thermal Processes Thermal processing accomplishes volume reduction of sludges and partial disposal to the atmosphere. All processes produce a residual that generally requires land disposal.
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From page 164... ...
The earlier comments about ash disposal and air emission problems caused by incineration also apply to pyrolysis through the gas-oil combustion step. Because pyrolysis is an incineration process, gaseous and particulate effluents from its separation and from use of its products must be reviewed in terms of airquality requirements and land disposal of its ash.
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From page 165... ...
5.3.2 Land-Based Alternatives Land disposal of sludges has been considered in detail in Chapter 3. However, certain features common to all the available land-based options for wastewater sludges should be emphasized.
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From page 166... ...
Suitable land disposal sites are also becoming increasingly scarce, particularly in urban areas, and an assumption that such sites will always be available may no longer be valid. S.3.3 Ocean-Based Alternatives A considerable amount of effort has been devoted to measuring the constituent elements in domestic and industrial wastes, analyzing concentration and dispersion in the marine environment, and assessing the effects of disposal on marine organisms that have direct or indirect contact with wastes.
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From page 167... ...
Enough information now exists about the New York and southern California Bights to allow a reasonable evaluation of the environmental impacts of specific discharges. This in turn allows a comparison with land or air disposal options to determine the disposal procedure most likely to cause the least net negative environmental impact.
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From page 169... ...
The technology is said to be ready for full-scale production, with between a half million and a million bricks already produced. 5.4 LOCAL CONSIDERATIONS Any environmental legislation or regulations to control the disposal of sewage sludge must allow decision makers sufficient flexibility to take local considerations into account.
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From page 175... ...
To be considered truly available, a sludge disposal process must have been either in operation for a number of years or must have recently gone through a procedure of laboratory evaluations, pilot plant operation, and expansion to a full-scale operational unit from which operational data suitable for design decisions are available. Sludge management or disposal systems are substantial public works projects with high capital costs that are designed to operate from 20 to 50 years.
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From page 176... ...
Such an evaluation would include a balancing of the environmental effects of sludge disposal options, utilizing a matrix approach that compares the potential effects of each option in each medium. Some of the comparisons will be quantitative, while others will be semiquantitative or qualitative.
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From page 177... ...
The background data that should be collected should include hydrological or meteorological data; sediment or soil quality data; fisheries or terrestrial population data and associated diseases; benthic or soil community data; and information on plant, animal, and human uptake of constituents of concern. Enough information on uptake has been collected to make reasonable multimedia assessments of potential effects on ecosystems or areas of particular interest such as public beaches.
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From page 178... ...
Using the various kinds of data mentioned above, comparative assessments can be made to determine whether disposal will lead to unreasonable short-term effects, unreasonable chronic effects, or the destruction of unique habitats. Another ecosystem issue that should be addressed is whether changes in the media that are caused by sludge disposal will be temporary or permanent.
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From page 179... ...
5.5.3 Conclusions A combination of quantitative, semiquantitative, and qualitative assessments will make it possible to address the issues raised by sludge disposal in each medium. These evaluations will be based on sludge characteristics, local physical characteristics, and the characteristics of local or regional media.
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From page 183... ...
1982. Health effects of water reuse by groundwater recharge, S5th Annual Conference Water Pollution Control Federation, St.
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From page 184... ...
1982. Pathogenic amoebae in ocean sediments near wastewater sludge disposal sites, J
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