Document Type

Journal Article

Department/Unit

Department of Biology

Title

Influence of different mixing ratios on in-vessel co-composting of sewage sludge with horse stable straw bedding waste: maturity and process evaluation

Language

English

Abstract

Composting sewage sludge alone would reduce the decomposition efficiency due to free limited porosity in sludge. To alleviate this, the use of horse stable straw bedding waste (HSB) was evaluated as a co-composting material with sewage sludge in a 10 tonnes day -1 in-vessel composter for a period of 7 days before curing in a static aeration pile. Sludge was mixed with HSB at 1: 1.5 (HSL) and 1: 2.9 (LSL) on a fresh weight basis. After a composting period of 56 days, both mixing ratios demonstrated to be feasible with LSL having a better organic decomposition and a shorter time to reach maturity. The overall decomposition rates were 52.0 and 58.9% (dry weight basis) for HSL and LSL, respectively. In both treatments, temperature in the in-vessel composters could reach 65°C, which was sufficient to remove the pathogens. Although both products were free of pathogens, HSL exhibited a higher ammoniacal nitrogen contents but a lower seed germination index than that of LSL indicating a higher phytotoxicity and a longer curing period would be required. It can be concluded that HSB provided a better composting conditions at a mixing ratio of 1: 2.9 © 2011 International Solid Waste Association.

Keywords

Co-composting, horse bedding waste, in-vessel, maturity, sewage sludge

Publication Date

2011

Source Publication Title

Waste Management and Research

Volume

29

Issue

11

Start Page

1164

End Page

1170

Publisher

SAGE Publications

DOI

10.1177/0734242X11420600

Link to Publisher's Edition

http://dx.doi.org/10.1177/0734242X11420600

ISSN (print)

0734242X

ISSN (electronic)

10963669

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