Crumbed rubbers

Crude tall oil Crude tall oil (CTO) Cruformate [299-86-5] Cruise missiles Crumb rubber Crushing... 

The opening between the wires of a screen, commonly used to describe particle size, e.g., of crumb rubber. The finer the mesh the more openings it will have per unit of width, i.e., 30 mesh describes 30 holes/inch. 

A term which generally applies to vulcanised rubber unfit for any other use than reclaiming or grinding to crumb rubber. In the rubber factory scrap may also refer to unvulcanised trimmings which can be reprocessed. 

More than 2 billion tires are disposed of annually in the USA. Before being recycled and/or reused, scrap tires or crumb rubber are first processed to remove any loose steel and fibers and then finely ground. Research has been conducted on the use of crumb rubber in highway construction such as in lightweight fill, subgrade insulation, and channel slope protection, as well as an additive to Portland cement concrete pavement [66,67,259,260]. 

North Carolina Department of Transportation Materials and Tests Unit (NC-DOT-MAT) (1993) A laboratory evaluation on crumb rubber on strength performance of concrete. Symposium proceedings Recovery and Effective Reuse of Discarded Materials and By-products for Construction of Highway Facilities. Federal Highway Administration, FHA, 34... 

Wet digestion, although not a paragraph 8 exclusion, was not studied because of the lack of plant-specific data. Emulsion and solution crumb rubber, although candidates for exclusion, were studied, because data were available. Source. USEPA. 

Toxic pollutants (kg/Mg) Emulsion crumb rubber manufacturing ... 

Organic toxic pollutants found at emulsion crumb rubber plants come from the raw materials, impurities in the raw materials, and additives to noncontact cooling water. BOD, COD, and TSS levels may also reach high loadings. 

Table 6 lists potential wastewater sources and general wastewater contaminants for the emulsion crumb rubber industry. 

Table 6 Summary of Wastewater Sources from Emulsion Crumb Rubber Production Facilities...

Crumb dewatering Crumb rinse water overflow Dissolved organics, and suspended and dissolved solids. Source of highest wastewater volume from emulsion crumb rubber production... 

Table 7 Summary of Wastewater Sources from Solution Crumb Rubber Production...

Plant 000012 produces 3.9 x 10" kkg/year (8.7 x lO lb/year) of emulsion crumb rubber, primarily neoprene. The contact wastewater flow rate is approximately 8.45 m /day (2.25 X 10 gpd) and includes all air pollution control equipment, sanitary waste, maintenance and equipment cleanup, and direct contact wastewater. The treatment process consists of activated sludge, secondary clarification, sludge thickening, and aerobic sludge digestion. Noncontact wastewater, with a flow rate of approximately 1.31 x 10 m /day (3.46 x 10 gpd), is used on a once-through basis and is remrned directly to the river source. Contact wastewater is also returned to the surface stream after treatment. 

Plant 000033 produces three types of emulsion crumb rubber in varying quantities. Styrene butadiene rubber (SBR) forms the bulk of production, at nearly 3.7 X lO kkg/year (8.2 X lO lb/year), with nitrile butadiene rubber (NBR) and polybutadiene rubber (PBR) making up the remainder of production [4.5 x 10 kkg/year (1.0 x lO lb/year) and... 

Plant 000027 produces polyisoprene crumb rubber [4.5 x 10" kkg/year (1.0 x 10 lb/ year)] polybutadiene crumb rubber, and ethylene-propylene-diene-terpolymer rubber [EPDM ... 

Table 10 Plant-Specific Verification Data for Emulsion Crumb Rubber Production Plant 000033...

Table 11 Plant-Specific Classical Pollutant Data for Selected Emulsion Crumb Rubber Production Plants, Verification Data...

At emulsion crumb rubber facilities, a well-operated biological treatment facility permits compliance with BPT limitations and reduces organic toxic pollutant levels. Toxic metals that may not be reduced include chromium, cadmium, copper, selenium, and mercury. Tables 16 and 17 show pollutant removal efficiencies at two emulsion cmmb plants. 

There are 13 solution crumb rubber plants in the United States. Twelve of these plants discharge treated wastewater to surface streams the other plant discharges its treated wastewater into a neighboring oil refinery s noncontact cooling water system. 

Tables 18 and 19 show pollutant removal efficiencies at two selected solution crumb rubber plants.

Table 16 Toxic Pollutant Removal Efficiency at Emulsion Crumb Rubber Plant 000012, Verification Data (Treatment Technology Activated Sludge, Discharge Point Surface Stream)...

Table 18 Toxic Pollutant Removal Efficiency at Solution Crumb Rubber Plant 000005...

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