Sewer systems, disposal

Transportation and Disposal. Only highly alkaline forms of soluble sihcates are regulated by the U.S. Department of Transportation (DOT) as hazardous materials for transportation. When discarded, these ate classified as hazardous waste under the Resource Conservation and Recovery Act (RCRA). Typical members of this class are sodium sihcate solutions having sihca-to-alkah ratios of less than 1.6 and sodium sihcate powders with ratios of less than 1.0. In the recommended treatment and disposal method, the soluble sihcates are neutralized with aqueous acid (6 Af or equivalent), and the resulting sihca gel is disposed of according to local, state, and federal regulations. The neutral hquid, a salt solution, can be flushed iato sewer systems (86). 

The presence of mineral oils and wastes from dry cleaning establishments makes sludge filtration difficult. Such wastes should, therefore, be kept out of the sewer system and disposed of separately. 

No liquid waste can be disposed of directly into the environment or into a storm sewer system. Unless collected and handed over to a waste disposal company, it goes into the sanitary sewer. There are specific rules concerning the quality of what may be disposed of in this manner. Materials that are routinely sent to the sewer from a home may not be permissible from a commercial source. Normally accepted waste water rules are often made more restrictive by local ordinance. 

Another pathway by which targeted pollutants enter the wastewater stream is through the disposal of spent batch process solutions into the sewer system. Spent solutions consist of aqueous wastes and may contain accumulated solids as well. Spent solutions are typically bled at a controlled rate into the wastewater stream. Other sources of pollutants in wastewater streams include cleanup of spills and washdown of fugitive aerosols from spray operations. 

Concentrated metal hydroxide sludge is pumped from the clarifier to a polypropylene plate filter press [T-102], The plate filter press56 is of sufficient capacity without any buildup in the lamellar portion of the unit. This also prevents any overflow of precipitate to the sewer system. The metal hydroxides form a dense sludge cake suitable for disposal in an approved landfill. The liquid effluent from the plate filter is returned to the surge tank [T-99],... 

An adequate drainage system should be provided for all locations where a large amount of hydrocarbon liquids has the possibility of release and may accumulate within the terms of the risk analysis frequency levels. Normal practice is to ensure adequate drainage capability exists at all pumps, tanks, vessels, columns, etc., supplemented by area surface runoff or general area catch basins. Sewer systems are normally gravity flow for either sanitary requirements or oily surface water disposal. Where insufficient elevation is available for the main header, lift stations are installed with a forced pressure outlet header to a disposal or treatment system. 

When water suppression systems are provided, due concern should be made for the disposal of the released water. Of primary importance are the capacity and location of surface drainage systems. Fire water usage usually places greater demands on a facility gravity sewer system than rainfall or incidental petroleum spillage effects. 

Be sure to consider the possibility of mixing materials in your waste disposal or sewer system. 

In addition to a system for disposing of rain, fire, and wash-down water, many process units require special dedicated sewer systems (i.e., chemical and oily water sewers) for routine nonemergency drainage of process waste due to environmental, waste disposal, cross-contamination, or reactivity reasons. Chemical, process, or oily water sewers are usually not appropriate in capacity or purpose for use in drainage of large uncontrolled process spills, rain water, or fire water. 

The generator must meet the concentration limits of the local sewer authority if discharging the waste to a sewer system is intended, or obtain a groundwater discharge permit from the State Division of Water Pollution Control if the generator discharges to a septic system or other groundwater disposal. If the waste or its pretreated effluent meets silver concentration limits of less than 5 mg/L of silver, the waste or the effluent is not classified as a hazardous waste. 

Established Exemption Levels. NRC s radiation protection standards in 10 CFR Part 20 (NRC, 1991) include limits on concentrations or annual releases of radionuclides for unrestricted discharge into sanitary sewer systems, except any excreta from individuals undergoing medical treatment with radioactive material are exempt from the limits. These regulations also include an exemption for land disposal of liquid scintillation materials and animal carcasses that contain 2 kBq g 1 (0.05 pCi g-1) or less of 3H or 14C, although the exempted scintillation materials must be managed in accordance with RCRA requirements due to the presence of toluene. 

KENNEDY, W.E., JR., PARKHURST, M.A., AABERG, R.L., RHOADS, K.C., HILL, R.L. and MARTIN, J.B. (1992). Evaluation of Exposure Pathways to Man from Disposal of Radioactive Materials into Sanitary Sewer Systems, U.S. Nuclear Regulatory Commission Report NUREG/CR-5814 (National Technical Information Service, Springfield, Virginia). 

It is illegal to dispose of cyanide solutions in municipal sewer systems (POTW — publicly owned treatment works). The cyanide ion must be destroyed prior to disposal. This is easily done using an aqueous solution of chlorine ... 

Limited quantities of some wastes can be disposed of in sanitary sewer systems but never in storm-sewer systems. A sanitary sewer is one that is connected directly to a waste-treatment plant, whereas a storm sewer usually discharges into a stream, river, or lake. 

The process of adsorption on carbon is applicable to wastewaters and polluted air. Treated waters may be suitable for reuse in industrial processes and can be discharged safely to the sewer system if removal efficiencies are high enough. Hazardous constituents of no commercial value that are removed may be disposed in burial sites after they have been stabilized. The high capacity of activated carbon for many compounds is attributable to the large surface area of the carbon (500-1500 m2 g-1). 

Methods and materials for containment and cleaning up Eliminate all ignition sources. Runoff may create fire or explosion hazard in sewer system. Absorb on fire retardant liquid-absorbing material (treated sawdust, diatomaceous earth, sand). Shovel up and dispose of at an appropriate waste disposal facility in accordance with current applicable laws and regulations, and product characteristics at time of disposal (see also Section 13). 

The primary remediation activity should be control of atmospheric releases or spills or run-off within the defined containment area, and to make certain that hazardous materials do not enter the sewer system, porous soil, or surface or ground water. This section of the plan should address not only the initial containment activity, but also post-incident clean-up, waste disposal, and environmental restoration. Safe clean-up methods should be outlined in the plan. 

Solutions of ammonia can be highly diluted with water, or alternatively, diluted with water and neutralized with HCl and then routed to the sewer system. The amount released to the receiving stream should not exceed the established limits for ammonia. Limited amounts of gaseous ammonia may be discharged to the atmosphere. Federal, state, and local guidelines should be consulted before disposal. 

DISPOSAL AND STORAGE METHODS dissolve in more flammable solvent and bum in incinerator equipped with effluent gas cleaning device dilute eoncentrations may be adequately treated by sewage organisms but should bot be allowed to enter sewers systems because of possibility of explosion store in a eool, dry location separate from oxidizers, peroxides or other initiators. 

SPILL CLEAN-UP ventilate area of leak or spill if possible use water spray to cool and reduce vapors in case of spill, soak up with dry earth, sand, or other non-combustible absorbent material and place into chemical waste container for proper disposal flush area with water, preventing entrance into drains, sewer systems, or natural water supplies remove all sources of ignition. 

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