Thesis Details

Thesis Title: Some parameters affecting the utilization of an overland flow textile wastewater treatment system
Thesis Author: Warren Owens
Abstract: The use of overland flow is currently being studied as a way to treat textile wastewater more cost-effectively " The response of this system to treating textile waste during cold weather and modified operating times is not fully understood. It is also not known whether treated effluent is amenable to polishing by sand filtration, or if operation of the system poses a ground water contamination problem. By measuring the performance of the system while operating in cold weather conditions and by modifying the application rate, ways of optimizing the system can be determined. By assessing the response. of the treated effluent to sand filtration, the potential for post-treatment by this method can be indicated. By evaluating the results of soil and soil moisture tests, the potential for ground water contamination can be assessed. Therefore, the objectives of this thesis investigation were to measure the performance of the overland flow system at Gordonsville Industries, Gordonsville, Virginia during cold weather operation, to measure the performance of the system with an operational change, to assess the response of the treated effluent to sand filtration, and to study the results of soil moisture and soil tests. Samples of the runoff were taken frequently during cold weather operation of the raw waste and the runoff effluent, and were measured for chemical oxygen demand, turbidity, percent transmission, conductivity, pH, and temperature. Soil temperatures were measured , and daily weather records were acquired through the state climatology office, to correlate with the results from the sample tests. Runoff flow, in gallons per minute, during normal and split loading operation was measured, and the treatea effluent was subjected to a series of tests for alum precipitation, laboratory scale sand filtration, industrial scale mechanized sand filtration and sand filtration by a sand strip near the bottom of the terrace slope. Soil and soil moisture test results were collated and reviewed. Re.sults from sample tests indicated that cold weather has a significant effect on treatment performance, and that operation of the system can be maintained during the winter, with a restriction for a low average air temperature cutoff point of about 34 degrees Fahrenheit with a freezing soil temperature. At these low temperatures the microorganisms perform aerobic oxidation at a very restricted rate and evapotranspiration and percolation are also reduced. Results of the operation modification indicated that peak flow and peak flow waste strengths can be reduced. Split loading gives the wastewater longer time on the slope and increases the opportunity for oxidation by microorganisms, filtration, adsorption, percolation, and evapotranspiration " Excluding the mechanized filter, test results indicated that there is good potential for sand filtration post-treatment of the runoff 1 because, the remaining color is mostly "apparent" as a result of colloids in suspension. Test results of soil and soil moisture do not indicate a ground water contamination problem. Year-round textile wastewater treatment by overland flow is technically feasible and can be enhanced by operation modifications and sand filtration post-treatment without posing a ground water contamination problem.