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theses

The goal of this research is to develop effective maintenance procedures and quantifying maintenance schedules for stormwater treatment systems, known as Hydrodynamic Separators (HDS). The HDS has started to be widely used with the purpose of removing pollutants from stormwater runoff and its use is expected to continue in the foreseeable future. Therefore, determining optimum maintenance procedures, intervals and costs is vital for their successful utilization. Information on the characteristics and location of each installed HDS is collected and identified through a field monitoring and maintenance study. Based on this information, twelve (12) HDS were selected and three (3) data forms are developed: asset data form, inspection data form, and maintenance data form to help level the playing field, properly track the devices, and inspect and maintain the devices in a timely fashion and in a cost-effective way. For analysis of quantity and quality of floatables, stormwater, and sediment, the quantities of bottom sediment, oil, and buoyant debris were measured and the samples of trapped water and bottom sediment were taken for the quality analysis. Measured quantity and quality of the trapped stormwater solids varied widely from site to site. Total depth of the bottom sediment ranged from 2.7 feet (exceeding the maintenance limit of 2 feet) to 0.5 feet. On average, about 90 percent of the solids trapped at the bottom had a mean particle size larger than 75 microns: coarse sediment. Organic content of the bottom sediment ranged from 3 to 34 percent. Concentrations of all the measured heavy metals (copper, zinc, lead, cadmium, and arsenic) in the bottom sediment were much lower than the New Jersey residential soil contamination limits indicating that the bottom solids can be disposed of at standard sanitary landfills. Concentrations of phosphorus and nitrogen in the bottom sediment were much lower than those in typical sewage sludge. The units were frequently (every two to three months) and continuously monitored across a full spectrum of storms. After three years of monitoring, six (6) devices had reached capacity, and they were cleaned out and restarted for monitoring. As a result of the monitoring and evaluation, an ideal and efficient maintenance procedure and interval are determined. For the general sites, the maintenance intervals were measured to be from three to four and one half years. For planning future maintenance/cleanout activities, it is recommended that the predictive model be used with the number of vehicles on the road(s) and the impervious drainage area as inputs.

ETD_5991

Ph.D.

Includes bibliographical references

by Jung-Hoon Kim

doi:10.7282/T3862DXG

ETD doctoral

The author owns the copyright to this work.