Discharges, multimedia

Pohution prevention techniques must be evaluated through a thorough consideration of ah media, hence the term multimedia. This approach is a clear departure from previous pollution treatment or control techniques where it was acceptable to transfer a pollutant from one source to another in order to solve a waste problem. Such strategies merely provide short-term solutions to an ever increasing problem. As an example, air pollution control equipment prevents or reduces the discharge of waste into the air but at the same time can produce a solid (hazardous) waste problem. 

The BAT level of treatment consists of all components of BPT except segregation and recirculation of quench wastewater. The combined wastewater after sedimentation is treated in multimedia filters and then discharged. 

The Level II calculation simulates a situation in which a chemical is continuously discharged into the multimedia environment and achieves a steady-state and equilibrium condition, at which input and output rates are equal. The task is to deduce the rates of loss by reaction and advection and the prevailing concentrations and masses. 

A direct assessment of multimedia behavior is thus possible by examining the proportions of chemical found at steady state in the source medium and in other media. For example, when discharged to water, an appreciable fraction of the benzene is found in air, whereas for atrazine, only a negligible fraction of atrazine reaches air. 

In this multimedia discharge scenario the overall residence time is 59 hours, which can be viewed as 60% of the air residence time of 19.7 h, 30% of the water residence time of 140 h and 10% of the overall soil residence time of 53 h. The overall amount in the environment of 59,000 kg is thus largely controlled by the discharges to water, which account for (0.3 x 133863) or 40,000 kg. 

A Phased Approach for Characterization of Multimedia Discharges from Processes... 

A multimedia concept that reduces or eliminates pollutant discharges to air, water, or land and includes the development of more environmentally acceptable products, changes in processes and practices, source reduction, beneficial use, and environmentally sound recycling. ... 

Loganathan BG, Irvine KN, Kaiman K, et al. 1997. Distribution of selected PCB congeners in the Babcock Street sewer district a multimedia approach to identify PCB sources in combined sewer overflows (CSOS) discharging to the Buffalo River, New York. Arch Environ Contam Toxicol 33(2) 130-140. 

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