Lined Surface Impoundments

The DEP recently issued a general permit authorizing the discharge of wastewater to lined surface impoundments. The Lined Surface Impoundment General Permit (LSI - NJ0142051) was developed to encourage the elimination of ground water discharges from unlined surface impoundments, basins or infiltration/percolation lagoons, and to simplify the regulatory requirements for permittees.

A surface impoundment is a natural topographic depression, man-made excavation, or diked area formed primarily of earthen materials, designed to hold an accumulation of liquid or solid wastes or wastes containing free liquids, excluding injection wells. Settling pits, aeration pits, ponds, and lagoons are all examples of surface impoundments. A lined surface impoundment has a continuous layer of soil or synthetic material that restricts the downward or lateral escape of any waste, waste constituents, or leachate. Eligible dischargers must have or install a liner with a hydraulic conductivity of 1 x 10-7 cm/sec or less. The impoundment must also have a permitted outfall, such as a discharge to surface water or a sanitary sewer, or incorporate a closed-loop recycling system that allows for reuse of accumulated pollutants.

For new construction, a lined surface impoundment authorized under this general permit must be completely constructed prior to commencing operation. Facilities that are regulated by another industry specific general permit are not eligible for this permit, but a facility with an individual NJPDES-Discharge to Ground Water permit for an unlined basin may choose to apply for the LSI general permit. This requires unlined basins be modified to include an impermeable liner as described above. In such cases, the liner is required to be installed within 18 months of authorization. The LSI general permit does not require discharge or ground water monitoring, nor does it include any Sludge Quality Assurance requirements.

The general permit was issued final on January 30, 2004 and became effective on March 1, 2004. Additional information on the LSI general permit can be obtained by contacting the Bureau of Nonpoint Pollution Control at (609) 292-0407. The permit can also be viewed on the Web at: www.state.nj.us/dep/dwq/nonpoint.htm.

Hot Mix Asphalt Producers Issued

The DEP developed a new NJPDES industry-specific stormwater general permit for stormwater discharges to surface and ground waters from Hot Mix Asphalt Producing (HMAP) facilities. After performing many site visits to HMAP facilities, the DEP determined a general permit would be the most efficient way to regulate these discharges, which have similar operations and discharges.

Currently, HMAP facilities have been operating under the Basic Stormwater General Permit or Individual Stormwater Permits. To consolidate permitting, the DEP worked with industry representatives to develop a general permit that covers all activities at these facilities. The HMAP General Permit includes Best Management Practices (BMPs) and monitoring requirements to prevent adverse environmental impacts. It also allows facilities the flexibility to create their own Stormwater Pollution Prevention Plans (SPPP) to meet their own individual conditions.

This permit authorizes new and existing discharges to the waters of the State with activities defined by SIC code: 2951, or NAICS code: 324121 (Asphalt Paving Mixtures and Blocks). The facilities eligible for the HMAP General Permit produce asphalt concrete (hot mix asphalt) as their industrial activity.

Permittees authorized under the HMAP General Permit will prepare, submit and maintain a SPPP which details facility operations, potential sources of pollutants, and BMPs the permittee will be implementing. The BMPs will be designed to meet numeric limits and benchmark concentrations for pollutants of concern at HMAP facilities. The permittee is also required to design and submit a Drainage Control Plan, demonstrating that all the stormwater from areas of industrial activity is captured and reused, diverted to regulated outfalls and/or has no exposure to source materials.

For more information about the HMAP Industry-Specific Stormwater General Permit, contact the Bureau of Nonpoint Pollution Control at (609) 633-7021 or visit the following web site: www.nj.gov/dep/dwq/gps.htm#stormwater.