Long-Term Objectives:

1. To determine the capability and the potential use of various soils and saprolites of North Carolina for on-site treatment and disposal of wastewater.

2. To evaluate various on-site wastewater disposal systems (septic systems) and improve their performance through development and/or modification of their design, installation, and management.

3. To develop methodologies for evaluation of soil physical and hydrological properties that are important in soil/site evaluation for selection, design, and installation of land-based waste disposal systems.

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Short-Term Objectives:

1. To assess the impact of wastewater quality on the performance of septic systems through evaluation of the effects of various constituents of wastewater on soil/saprolite hydraulic properties.

2.. To evaluate the use of lime or other sources of calcium for restoring the hydraulic capacity of soil/saprolite after receiving wastewater containing a high level of sodium.

3. To assess the potential use of tire chips in place of gravel in the trenches of septic systems.

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Accomplishments:

1. Evaluated the performance of a number of low-pressure pipe and drip septic systems for the disposal of wastewater and made recommendations regarding their design and installation.

2. Evaluated movement of water and solutes through different soils and saprolites and determined that, in general, the parent rock features and closed fractures of saprolite do not contribute to preferential flow.

3. Designed a portable device for in situ evaluation of soil hydraulic conductivity. The device is used by USDA-NRCS, consultants, and researchers interested in water movement and/or waste management.

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Significance of Accomplishments:

The results of various research programs were used to assist the staff of On-Site Wastewater Section, Division of Environmental Health, NCDEHNR, to develop new regulation to expand the use of saprolite for wastewater disposal. Based on these regulations, more land can be developed for housing with septic systems.

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Future Plans:

1. To work with the state regulatory agencies and provide technical support through field and laboratory research projects to design, install, and manage land-based waste disposal systems that do not pollute surface and ground water resources.

2. To study a number of soil and saprolite sequences in the Piedmont region from the land surface to bedrock and asses their role in the transport of pollutants from land-based waste disposal systems.

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