Sewers, discharge limits

As discussed in Chapter 17, legislative controls including stringent consent conditions are applied in the UK to all discharges to specified sewers. (Discharge of effluent to surface water drains is prohibited.) Limits, or even total prohibitions, are placed upon certain chemicals to avoid... 

Waste disposal and treatment facilities have their own requirements for acceptance of waste. For example, wastewater may be discharged into sanitary sewer if it meets the requirements of the POTW batch discharge permit. This permit will list the analytes, methods, and discharge limitation concentrations (action levels). Disposal facilities (e.g. landfills) have lists of analyses that must be performed as a condition of waste acceptance by the facility. 

The permeate could be treated on-site with additional treatment equipment to reduce contaminant levels for either surface water body discharge or sewer discharge. Treatment, such as with activated carbon, may be necessary to reduce contamination to acceptable limits. The use of additional treatment equipment will increase remediation costs and may necessitate additional disposal requirements. 

Rinsing is a process technology that needs particular attention because of the multiple needs of uncontaminated panels, conservation of rinse waters, and environmental discharge limitations. It is no longer sufficient to flood the panel with large amounts of water that are then discharged to sewers. The capability of technical analysis of this process has been published. ... 

Protection of the environment from uncontroHed radioactive release is also a consideration in the use of radiotracers. The quantity and concentration of radionucHdes that may be discharged into sewer systems is limited by regulations of the Nuclear Regulatory Commission (NRC). 

Waste water rules have pH limits, a common range being between 6 and 10. There are also limits for fats and oils, solvents, heavy metals, and a variety of other compounds and ions. The fact that a compound with possible toxic or otherwise undesirable properties is not on the list does not mean it is permissible. Such a matter should be discussed with the proper authorities. The discharged water may also have to pass a test for toxicity to aquatic animals. As one frustrated manager of a chemical plant put it We can no longer put anything but pure tap water into the sewer Of course, it is not really that bad, but some of the requirements often come as a surprise. 

Both urban and industrial wastewater often contains high concentrations of surfactants. Cationic (like alkylbenzene sulphonates) and non-ionic surfactants (like alcohol ethoxylates) are among the most-used surfactants and are discharged into sewers in widely varying concentrations. Two on-line methods have been designed for the monitoring of cationic surfactants with UV spectrophotometry [46] and non-ionic surfactants by on-line titration [47]. The detection limits are around 10 mg L. ... 

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. 

These requirements recently replaced earlier legislation dating from 1984 [3.157], Lower limits might be set by local or regional authorities, even for nondirect discharges into municipal sewer systems. 

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. 

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. 

Perhaps the most common disposal method for RO reject is simply sending it down the drain to sewer or waste treatment. However, discharging in this manner may actually not be a simple as it sounds. There are regulations and permits that may be required that limit discharge of specific contaminants. 

Where waste water is discharged into the sewers with the agreement of the local water authorities, a charge will normally be made according to the BOD value, and any treatment required. Where treated effluent is discharged to water courses, with the agreement of the appropriate regulatory authority, the BODS limit will typically be set at 20 ppm. 

In the manufecture of vinyl acetate, there is some unreacted acetic acid and other compounds that are discharged to the sewer. Your company has been cited as discharging more than the specified limit of several pollutants. It is not possible to measure the discharge directly because no flow measuring devices are in place, but you can take samples of liquid at different places in the sewer line, and measure the concentration of potassium chloride. At one manhole, the concentration is 0.105%. You introduce a solution of 400 g of KCI in IL at a steady rate of 1 L per minute over 5 hr at a manhole 500 ft downstream, and at 1200 ft downstream measure the average steady-state concentration of KCI as 0,281%. What is the flow rate of fluid in the sewer in kg/min ... 

Direct discharges from point source limitations. Point sources include sewers, pipes, drainage ditches, etc. Any facility that intends to discharge into a lake or stream or river must obtain a permit prior to initiating the discharge. The discharge must meet conditions and effluent limitations set by the state and/or EPA. 

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. 

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