Article | August 23, 2013

Tightening NPDES Guidelines: Industrial Plants Beware

CoalFiredPowerPlant

By Brad Buecker, process specialist, Kiewit Power Engineers

Multiple methods of dealing with waste stream discharges are examined in light of the recent clampdown on industrial processes.

I began my career in the power industry in 1981 at a coal-fired plant in the Midwest. At that time, U.S. EPA National Pollutant Discharge Elimination System (NPDES) guidelines focused upon a small core of primary impurities in wastewater discharge streams. These included total suspended solids (TSS), oil and grease (O&G), pH, and free chlorine (or other oxidizing biocide). A common guideline is shown below in abbreviated form.

My former plant, like many other plants then, utilized once-through cooling, so these limits were often easy to achieve. The majority of problems arose at coal-fired power plants from the discharge of coal-pile runoff ponds and wet-ash disposal ponds. The constituents in these streams that required the most oversight tended to be TSS and pH, but straightforward methods were available to control this chemistry.

Image credit: "Coal-Fired Power Plant at Sunset, Turceni," © 2012 Emilian Robert Vicol, used under an Attribution-ShareAlike 2.0 Generic license: http://creativecommons.org/licenses/by-sa/2.0/deed.en