Abstract

In recent times, municipalities have turned to yard waste composting in an effort to comply with mandated recycling and reduction laws aimed at extending existing landfill capacity. Composting is a biological process whereby decomposition of organic matter occurs under aerobic conditions, producing a stabilized humified material. The objective of the research was to analyze data gathered during pilot yard waste composting operations utilizing the windrow method. The following tasks were accomplished: temperature and oxygen profiles from daily monitoring data were examined and the effect these parameters had on stabilization was determined; stabilization time of varying yard waste matrices was compared and related to compost physical-chemical characteristics; oxygen uptake and aeration mechanisms as a function of waste type were determined, and based upon the preceding items, recommendations were provided on process optimization. The research determined that yard waste composition did not have a significant effect on stabilization time, with the exception of extremely woody wastes. Stabilization occurred in approximately 90 days. Biological activity significantly declined between 40 and 60 days as indicated by the decrease in average windrow temperature and oxygen uptake rate {OUR). Aeration rates within the windrow were estimated using a convection rate model. Convection rates increased with increasing particle size and temperature. As compost age increased, convection rates decreased as particle size and temperature decreased. A comparison of convection and oxygen uptake rates as a function of composting conditions suggested four phases of the composting process. The highest convection rates were found in the early stages of composting of yard wastes with large particle size. Anaerobic conditions were only prevalent in the early stages of composting in windrows containing mostly grass and having the smallest particle radius. At this time oxygen uptake rates were high but lower convection rates resulted due to smaller particle size. As composting progressed and stabilization occurred, OUR declined due to decreased biological activity and oxygen levels increased. Furthermore, convection rates declined as a result of smaller particle size and lower temperatures.

Notes

This item is only available in print in the UCF Libraries. If this is your thesis or dissertation, you can help us make it available online for use by researchers around the world by STARS for more information.

Graduation Date

1991

Semester

Spring

Advisor

Reinhart, Debra R.

Degree

Master of Science (M.S.)

College

College of Engineering

Department

Civil and Environmental Engineering

Format

PDF

Pages

121 p.

Language

English

Length of Campus-only Access

None

Access Status

Masters Thesis (Open Access)

Identifier

DP0028044

Subjects

Dissertations, Academic -- Engineering; Engineering -- Dissertations, Academic

Accessibility Status

PDF accessibility verified using Adobe Acrobat Pro Accessibility Checker.

Share

COinS