The Pennsylvania Environmental Quality Board recently passed an amended version of new regulations aimed at controlling the discharge of total dissolved solids (TDS) into Pennsylvania waters. TDS is the measure of all solids found in a dissolved state in water, but is comprised mainly of salts such as chlorides and sulfates. The proposed Pennsylvania regulations will limit oil and gas industry related wastewater to 500 mg/l and all other wastewater to 2000 mg/l. Secretary John Hanger of the Pennsylvania Department of Environmental Protection explained that the reason for the disparate application of the discharge rule was the extremely high levels of TDS in oil and gas industry process water and the potential for its re-use and alternative means of disposal, such as underground injection.
Following Pennsylvania?s lead, the West Virginia Department of Environmental Protection (WVDEP) announced a new standard for TDS through proposed amendments to the state's water quality standards. Unlike Pennsylvania, the proposed WVDEP rule would apply the 500 mg/l standard to all in-stream discharges across all industries. The Ohio River Valley Sanitation Commission (ORSANCO), an interstate commission representing eight states and the federal government, has commenced rule-making to propose the standard of 500 mg/l on all discharges into the Ohio River.
These proposed rules come after instances in the past two years where the Monongahela River has shown levels of TDS above 500 mg/l at drinking water intakes during very low flow periods, resulting in general complaints regarding the taste of the water. The rules also follow an incident in Dunkard Creek, which travels along the West Virginia-Pennsylvania border, where an extremely high TDS content water entering from an underground source resulted in an unprecedented golden algae bloom and a subsequent fish kill.
TDS is already regulated as a secondary drinking water pollutant under the Safe Drinking Water Act (SWDA). TDS is generally not considered a threat to public health or aquatic life, and the SWDA's 500 mg/l standard for drinking water relates to the aesthetics of the water, not public health. Wastewater treatment facilities, particularly publicly owned treatment works, are generally not designed to treat for TDS, and treatment of water to remove TDS would necessitate the installation of substantial capital improvements for sanitary sewer services. Treatment to levels below the proposed standard is extremely expensive, and many question what, if any, environmental benefits are gained from treatment of TDS to such low levels.
The Pennsylvania rule now moves to the Environmental Resources and Energy committees in both houses of the state legislature and to the Independent Regulation Review Committee for final consideration. The proposed West Virginia rule must proceed through the legislative rule-making process. Approval of the West Virginia rule will require passage by both houses of the legislature, approval of the Governor, and final approval by the United States Environmental Protection Agency.