Best practical technology

Best practical technology (BPT) refers to any of the categories of technology-based effluent limitations pursuant to Section 301(b) and Sections 304(b) of the Clean Water Act as amended. These categories are the best practicable control technology currently available (BPT); the best available control technology (BAT) economically feasible (BAT); and the best conventional pollutant control technology (BCT).

Section 301(b) of the Clean Water Act specifies that "in order to carry out the objective of this Act there shall be achieved—(1)(A) not later than July 1, 1977, effluent limitations for point sources, other than publicly owned treatment works (i) which shall require the application of the best practicable control technology currently available as defined by the Administrator pursuant to Section 304(b) of this Act, or (ii) in the case of discharge into a publicly owned treatment works which meets the requirements of subparagraph (B) of this paragraph, which shall require compliance with any applicable pretreatment requirements and any requirements under Section 307 of this Act;..."

The BPT identifies the current level of treatment and is the basis of the current level of control for direct discharges. BACT improves on the BPT, and it may include operations or processes not in common use in industry. BCT replaces BACT for the control of conventional pollutants, such as biochemical oxygen demand (BOD), total suspended solids (TSS), fecal coliform, and pH . Details such as the amount of constituents, and the chemical, physical, and biological characteristics of pollutants, as well as the degree of effluent reduction attainable through the application of the selected technology can be found in the development documents published by the Environmental Protection Agency (EPA). These development documents cover different industrial categories such as diary products processing, soap and detergents manufacturing, meat products, grain mills, canned and preserved fruits and vegetables processing, and asbestos manufacturing.

In accordance with Section 304(b) of the Clean Water Act, the factors to be taken into account in assessing the BPT include the total cost of applying the technology in relation to the effluent reductions to the results achieved from such an application, the age of the equipment and facilities involved, the process employed, the engineering aspects of applying various types of control technologies and process changes, and calculations of environmental impacts other than water quality (including energy requirements). As far as evaluating the BCT is concerned, the factors are mostly the same. By they include consideration of the reasonableness of the relationship between the costs of attaining a reduction in effluents and the benefits derived from that reduction, and the comparison of the cost and level of reduction of such pollutants from the discharge from publicly owned treatment works to the cost and level of reduction of such pollutants from a class or category of industrial sources. Control technologies may include in-plant control and preliminary treatment, and end-of-pipe treatment, examples of which are water conservation and reuse , raw materials substitution, screening, multimedia filtration , and activated carbon absorption .

[James W. Patterson ]