7 Del. Admin. Code § 7103-40.0
Current through Register Vol. 28, No. 4, October 1, 2024
Section 7103-40.0 - Introduction40.1 (Subsection 101) Purpose 40.1.1 This document provides regulations for the planning, design, and operation of slow rate land treatment systems for wastewaters in Delaware. These guidelines and regulations do not apply to overland flow or rapid infiltration systems. Furthermore, these regulations supersede Section 9 - Effluent Limitations for Land Disposal of Liquid Waste - Part I regarding Spray Irrigation of Liquid Waste as set forth in the Department's Regulations Governing the Control of Water Pollution, adopted March 15, 1974 and amended on June 23, 1983.40.1.2 The Delaware Department of Natural Resources and Environmental Control encourages slow rate land treatment as an alternative to advanced wastewater treatment, particularly in environmentally sensitive areas of the State. In addition, slow rate land treatment, or wastewater irrigation, is encouraged for wastewater treatment in small to medium sized communities and industries where appropriate.40.1.3 The term slow rate land treatment as used in these regulations refers to the advanced treatment of wastewater by irrigation onto land to support vegetative growth. These systems are designed and operated so there is no direct discharge to surface waters. The irrigated wastewater evaporates and transpires to the atmosphere or enters the groundwater through percolation. Organic constituents in the wastewater are stored in the soil or stabilized by soil bacteria. Organic and ammonia nitrogen are taken up by plants, nitrified by soil bacteria, lost to the atmosphere through denitrification, and leached groundwater. Phosphorus and other constituents are adsorbed in the soil profile and/or taken up by plants. Properly designed and operated wastewater irrigation systems produce a percolate water of high quality and thus protect ground and surface water resources.40.1.4 The regulations outlined herein apply to wastewaters with and without domestic wastes. A distinction is made between the two types of wastewaters because of the public health issues associated with domestic wastes. Wastewater irrigation systems for industrial and animal wastes may depart somewhat from these regulations and, if so, will be evaluated by the Department on an individual basis.40.1.4 The design and operation of wastewater irrigation systems is very site specific. This document is intended to provide regulations and general guidelines for design and operation of slow rate land treatment systems in Delaware. However, hydrogeologic and soil conditions vary widely throughout the State and site assessment and monitoring requirements may vary not only from region to region but even from site to site within the same region.7 Del. Admin. Code § 7103-40.0