Graduate Thesis Or Dissertation
 

Effects of pressure and deposit thickness on the stabilization rate of benthic marine sludge deposits

Public Deposited

Downloadable Content

Download PDF
Request Accessible Version
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/sq87bw799

Descriptions

Attribute NameValues
Creator
Abstract
  • The biochemical degradation of domestic sludge deposits exposed to benthic marine conditions was investigated using a laboratory Deep Sea Simulator. The rate and extent of deposit stabilization were determined for select hydrostatic pressures and hydrogen acceptor conditions by monitoring depletion of particulate organic carbon in 2.0 and 3.0 centimeter deposits. The extent of aerobic and anaerobic-exogenous zones in a 33 centimeter deep deposit was determined by measuring dissolved oxygen, sulfate and hydrogen sulfide concentrations as a function of distance from the deposit surface. Marine deposit stabilization processes and a set of mathematical expressions for temporal particulate organic carbon changes were formulated based on studies of fresh water organic matter stabilization and characteristics of the benthic marine environment. Aerobic depletion of particulate organic carbon amounted to between 14 and 19 percent in 20 days. After 120 days, depletion reached 30.6 percent ([superscript k]avg = 0.042 day ⁻¹ ) and the remaining refractory component was 0.21 mg-C/mg solid. Thereafter, degradation proceeded slowly. Comparable anaerobic decreases were 2.5 to 4.0 percent in 20 days and 7.0 percent in 130 days ([superscript k]avg = 0.024 day ⁻¹ ). Calculated anaerobic particulate organic carbon residuals ranged from 0.25 to 0.28 mg-C/mg solid. Differences in the aerobic and anaerobic biochemical depletion rates resulted in a 30 percent higher particulate organic carbon concentration in the anaerobic zone than in the near-surface aerobic zone in 120 days. Variance analyses confirmed the significance of degradation rate differences as a function of hydrogen acceptor zone, but indicated that differences were not significant for hydrostatic pressures of one and 34 atmospheres. Interactive hydrostatic pressure/hydrogen-acceptor-type effects were also found to be insignificant. The sludge deposit aerobic zone extended from the sea water/ sludge interface to approximately two millimeters. The anaerobicexogenous zone (defined by a ten-fold reduction in the surface dissolved sulfate concentration) extended from the dissolved oxygen diffusion limit to approximately 16 centimeters deep in a 33 centimeter deposit, 180 days after deposit formation. Hydrogen sulfide concentrations in excess of 500 mg/1 were measured at the 16 centimeter depth in the 33 centimeter deposit, whereas the maximum hydrogen sulfide concentration measured in 2.0 and 3.0 centimeter deposits was 20 mg/l. Although aerobic particulate organic carbon degradation rates were larger than anaerobic rates, overall depletion of particulate organic carbon occurred principally in the anaerobic zone which was 15 times greater than the aerobic zone in a 3.0 centimeter deposit. Study findings indicate that the formation of marine sludge deposits which are greater than a few millimeters in depth enhances material preservation. When deposits become deeper than a few centimeters, dissolved hydrogen sulfide may accumulate to levels known to be toxic to marine organisms.
Resource Type
Date Available
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Publisher
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome, 8-bit Grayscale) using ScandAll PRO 1.8.1 on a Fi-6670 in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
Replaces
Accessibility Feature

Relationships

Parents:

This work has no parents.

In Collection:

Items

Thumbnail Title Date Uploaded Visibility Actions
file details MuellenhoffWilliamP1977.pdf 2017-08-07 Public Download