On August 21, 2010, new wastewater management regulations governing total dissolved solids (TDS) discharges became effective upon publication in the Pennsylvania Bulletin by the Department of Environmental Protection (DEP or Department). The new regulatory limit for discharges of wastewater from natural gas drilling operations is a concentration of 500 milligrams per liter (mg/l) of total dissolved solids and 250 mg/l for chlorides. All new and expanding facilities that treat wastewater from natural gas wells must now meet these discharge limits. The wastewater cannot be discharged directly from the wells but must be sent to a treatment facility prior to discharge.  

The new rule also imposes an effluent standard for all other discharges of 2,000 mg/l of TDS on a monthly average, unless a variance is approved by the Department or the discharge is otherwise expressly exempt. Although much of the debate has focused on the impact to the developing Marcellus Shale in the oil and gas industry, the rule also applies to new or expanded discharges exceeding a 2,000 mg/l TDS threshold in the mining, electric power generation, petroleum refining, chemical manufacturing, and steel manufacturing industries. The Department has sought to limit the impact of the final rule by providing certain express exemptions, including those for existing surface mining activities, and certain existing publicly-owned treatment works (POTW) and discharges from industrial categories for TDS, chlorides or sulfates established as best available technology economically achievable (BAT), best conventional pollution control technology (BCT) or new source standards of performance by EPA. For oil and gas operations, a limited variance provision is available only in situations where a watershed analysis is conducted by the Department demonstrating that an approved variance will not result in a reduction of the assimilation capacity for TDS to less than 25 percent of the total available assimilation capacity of the downstream point, and when the resulting in-stream concentrations at the point of discharge from the new or expanded loading to the receiving stream will not otherwise violate water quality standards in Chapter 93 of the Department's regulations.  

DEP is developing guidance documents to address compliance issues. On August 21, DEP released its first guidance document in an effort to provide clarification of the key term "authorization by the Department." Any maximum daily discharge loads of TDS that were authorized by the Department prior to the effected date (August 21, 2010) are not considered new and expanded mass loadings of TDS, and are therefore exempt from treatment requirements. Under this guidance, the Department applies a broad interpretation of "authorization" that includes those permitted levels registered, approved, certified or otherwise granted permission by DEP prior to August 21, 2010. (See DEP Guidance Chapter 95 — Total Dissolved Solids, Statement of Policy Defining the Term "Authorization," Document no. 385-0810-001).

The impact of this regulation is significant and immediate for large volume waste water discharges. First, all industrial waste dischargers must carefully evaluate the volume and constituencies of their wastewater and potential increases. A review of the exemptions and forthcoming guidance documents is prudent for business planning. Second, those regulated TDS dischargers must conduct extensive due diligence to identify a reliable treatment technology and permitted treatment facility, as available treatment technologies are limited and wastewater composition varies among industrial sectors. Therefore, the application of reverse osmosis and evaporation/crystallization, or a combination, may be required. These operational and compliance issues must be periodically reviewed to avoid unwanted administrative action and potential penalties.