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INFORMATION SHEET <br /> 9 <br /> GENERAL ORDER FOR DISCHARGE OF <br /> GROUND WATER FROM CLEANUP OF <br /> PETROLEUM FUEL' POLLUTION <br /> TO SURFACE WATERS <br /> This- Order serves as a ,'�general NPDES Permit for the discharge to surface water <br /> of ground water from the investigation and cleanup of ground water polluted with <br /> petroleum fuels, such as gasoline, diesel , and heavier fuel oils. The wastewater <br /> will, be discharged to surface water and surface water drainage courses. The <br /> treatment and discharge', of ground waters polluted with other chemicals, such as <br /> industrial solvents or , pesticides,] are not: covered by this Order. Also not <br /> covered by this Orderijare I) Treated waste waters discharged to'municipal <br /> wastewater collections systems (which do not need waste discharge requirements <br /> from the Board) , and 2) discharges to ponds, infiltration basins, spray disposal <br /> areas,: subsurface .infiltration, or;jother methods not involving discharge to C <br /> surface waters and surface water drainage courses (which are covered by general <br /> waste discharge requirements for land disposal adopted by the Board). <br /> The presence of fuel constituents in,l-the ground water poses a 'threat to existing <br /> and potential beneficial uses of the ground water. The number of proposed and <br /> ongoing ground water cleanups of fuel constituents is increasing. The primary j <br /> constituents of concern with fuels are: Total Petroleum Hydrocarbons in the <br /> gasoline, diesel and heavier. ranges;I�Benene; Toluene; Xylene; Ethylbenzene; and <br /> Tetraethyl lead. Existing wastewater treatment technology, primarily utilizing <br /> air stripping and/or activated carbon, 'is capable of dependably removing these <br /> constituents to concentrations which are generally non-detectable by current <br /> analytical technology. ij ? Wastewater., from a ground water cleanup may include: <br /> treated ground water which had been polluted with fuel constituents; unpolluted <br /> ground water pumped -fromin beneath a layer of free product in order to establish <br /> a cone of depression to aid in the containment and extraction of the free <br /> product; extracted water from short- and long-term pump tests; well development <br /> water; purge water prior to well sampling. These wastewaters may be produced and i <br /> treated on a continuousj,or batch bas'is. ,. Treated wastewater will be disposed of } <br /> to surface water and -surface water drainage courses. <br /> al The monitoring program. enclosed within this general permit has been set up for <br /> a typical ground water extraction/treatment facility. The monitoring program can <br /> be changed to address site-specific,irconcerns (sensitivity of- receiving waters, <br /> reliability of treatment unit, etd. ) ;by issuing a separate Monitoring and <br /> Reporting Program which either increases or decreases the monitoring frequency. <br /> If the monitoring frequency is: decreased the monitoring program may need to be <br /> re-noticed and sent out�for comments`. <br /> Effluent limits have been established as follows: <br /> i <br /> r <br /> a. 30-Day Median Concentrations for TPH, Benzene, Ethylbenzene, Toluene, and <br /> Xylene are established ' as ''non detectable' , that is, less than the <br /> detection concentrations for -specified, commonly available analytical <br /> technology. A 'median' is used rather than an 'average' or 'arithmetic , <br /> mean' to allow for the detection of a constituent in individual samples l <br /> without automatically causing-! violation of the monthly limitation, as <br /> i <br />