Design and management of composting systems

Hewings, Guy 2007. Design and management of composting systems. PhD Thesis, Cardiff University.

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Abstract

Composting is an effective method of removing a large proportion of biodegradable waste from landfill. The CO2 produced by microbial activity demonstrates the rate of decomposition, and was measured in green waste composting in windrows, a forced aerated bay, an aerated test rig and related to the volatile solid content. The peak respiration rates were 35gC02kgVS',day'1 in windrows, and 290gCO2kgVS'1day'1 in the test rig. Knowing the rate of microbial activity, allows the volume of air required to supply sufficient oxygen to a composting matrix to be determined. Recently introduced treatment regulations require 100% of the waste in a composting system to be maintained above 60 or 70 C for minimum periods. Aeration management methods were evaluated that maximise the rate of temperature increase and distribute the heat generated by microbial activity. Managing re-circulated gases between set CO2 limits was demonstrated to an effective method of encouraging rapid temperature increase. Whilst the lowest recirculation rate of 40m3hr l per m3 of compost was required to ensure 100% of the compost matrix in the test rig was greater than 60 C. The research presented in this thesis demonstrates methods that will aid the design and management of any composting system, especially those treating catering waste.

Item Type:	Thesis (PhD)
Status:	Unpublished
Schools:	Engineering
Subjects:	T Technology > TD Environmental technology. Sanitary engineering
ISBN:	9781303224454
Funders:	Landfill Tax Credit Scheme
Date of First Compliant Deposit:	30 March 2016
Last Modified:	10 Jan 2018 02:52
URI:	https://orca.cardiff.ac.uk/id/eprint/55167

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