Type of Document Master's Thesis Author Ijzerman, M. Marian URN etd-03242009-040620 Title Evaluation of shallow-placed low pressure distribution systems in soils marginally suited for on-site waste treatment Degree Master of Science Department Crop and Soil Environmental Sciences Advisory Committee
Advisor Name Title Hagedorn, Charles III Committee Chair Benoit, Robert E. Committee Member Reneau, Raymond B. Jr. Committee Member Keywords
- Sewage disposal in the ground
Date of Defense 1990-06-14 Availability restricted AbstractTwo shallow-placed low pressure distribution (LPD) systems were evaluated in soils that were marginally suited for a conventional on-site wastewater disposal system (OSWDS) because of low hydraulic conductivity and shallow depth of soil to bedrock. The soils used for this study were Edom (fine, illitic, mesic, Typic Hapludult) and Penn-Bucks soil (fine-loamy, mixed, mesic, ultic Hapludult). In the Edam soil, the LPD system was installed with four subsystem designs operating: a narrow trench design with a design loading rate of 17.5 Lpd/m2, and three designs based on Virginia regulations with design loading rates of 9.0 Lpd/m2, 4.5 Lpd/m2, and 5.7 Lpd/m2. In the Penn-Bucks soil, the LPD system was installed with three subsystem designs operating: a narrow trench design with a design loading rate of 30.6 Lpd/m2, and two designs based on Virginia regulations with design loading rates of 14.3 Lpd/m2, and 7.3 Lpd/m2.
The evaluation was conducted under different moisture and temperature conditions (summer of 1989, and the winter of 1990), and focused on the fate and transport below each system of two antibiotic resistant Escherichia coli strains and two host-specific bacteriophage strains. The potential loss of N03"-N through the biological process of denitrification was also examined.
In the Edom soil, a narrow trench design, and designs based on the Virginia regulation all removed >99.9% of the bacterial and viral tracers during the summer of 1989, and >99% during the winter of 1990 throughout a 152 cm depth. The potential loss of N03"-N in the Edom soil by denitrification was estimated to be 38%.
In the Penn-Bucks soil, the narrow trench design failed within six months of installation because the effluent loading rate was too high to permit infiltration through the silty clay loam soil, once biological clogging developed with the subsequent decrease in infiltrative capacity. The lower Virginia loading rate was nlore effective at microbial retention with >99.9% removal throughout a 114 cm depth in both the summer of 1989 and the winter of 1990. The normal Virginia loading rate removed> 99% of the bacterial and viral tracers throughout a 102 cm depth in both the summer of 1989 and the winter of 1990. The overall loss of N03"-N in the Penn-Bucks soil through denitrification was estimated at 67%.
Filename Size Approximate Download Time (Hours:Minutes:Seconds)
28.8 Modem 56K Modem ISDN (64 Kb) ISDN (128 Kb) Higher-speed Access LD5655.V855_1990.I493.pdf 80.12 Mb 06:10:54 03:10:45 02:46:54 01:23:27 00:07:07next to an author's name indicates that all files or directories associated with their ETD are accessible from the Virginia Tech campus network only.
If you have questions or technical problems, please Contact DLA.