Anaerobic co-digestion of food waste and brown water

Anaerobic digestion technology is one of the sustainable approaches to convert wastes into a biogas that provides a renewable energy source to replace the diminishing non-renewable natural resources. This research was mainly to study the performance of anaerobic co-digestion of food waste and brown...

Full description

Saved in:
Bibliographic Details
Main Author: Leong, Yuan Shan.
Other Authors: School of Civil and Environmental Engineering
Format: Research Report
Language:English
Published: 2011
Subjects:
Online Access:http://hdl.handle.net/10356/45737
Tags: Add Tag
No Tags, Be the first to tag this record!
Institution: Nanyang Technological University
Language: English
id sg-ntu-dr.10356-45737
record_format dspace
spelling sg-ntu-dr.10356-457372023-03-03T16:43:40Z Anaerobic co-digestion of food waste and brown water Leong, Yuan Shan. School of Civil and Environmental Engineering DRNTU::Engineering::Environmental engineering::Waste management Anaerobic digestion technology is one of the sustainable approaches to convert wastes into a biogas that provides a renewable energy source to replace the diminishing non-renewable natural resources. This research was mainly to study the performance of anaerobic co-digestion of food waste and brown water at different organic loading ratios. Monitoring parameters include the measurement of pH, volatile solids reduction, chemical oxygen demand (COD), alkalinity, volatile fatty acids (VFA) concentration, biogas composition, methane yield, and methane production rate. The experiments were conducted at a temperature of 35°C. The organic loadings for the anaerobic digestion of food waste and brown water were 0.3gVS/L, 0.5gVS/L, 1.0gVS/L and 2.5gVS/L. Both digestions had shown decreased pH and increased VFA concentration in the initial phase of the digestion. Smaller organic loadings yielded higher methane gas for every gram of VS added to the both systems, while higher organic loadings had higher methane yield per gram of VS or COD removed. 80% of methane yield per VSadded for both digestions had been achieved in the first 10 days, with methane contents in the range of 50-80%. Low pH and VFA accumulation may be the result of inhibition of the methanogens, affecting the methane yield. Food waste yielded lesser methane than brown water, with likelihood of inhibition effects due to high oil content in the food waste. Based on the digestion of food waste and brown water, co-digestion was conducted with the organic loading ratios of 0.5:0.5, 0.3:0.7, 0.7:0.3 and 1:1 brown water versus food waste. Either combinations of 0.3gVS/L of food waste and 0.7 gVS/L of brown water or 0.7gVS/L of food waste and 0.3 gVS/L of brown water yielded halved as much as the digestion of the substrates individually. As for the 0.5gVS/L and 1.0gVS/L loadings, co-digestion also yielded lesser methane than individual digestion. The results suggest that co-digestion failed to improve methane production rates and that the anaerobic digestion of food waste and brown water are incompatible. It could be due to microbial interactions of the microorganisms from both substrates when they were mixed such as amensalism where either one microbial population caused inhibitory effects to the other population, or due to chemical reactions of fermentation by-products of food waste and brown water digestion. Further studies recommended include the explicit study on the microbial interactions of food waste and brown water in municipal sewage sludge, and the chemical reactions pathway of co-digestion of food waste and brown water. 2011-06-16T08:32:38Z 2011-06-16T08:32:38Z 2011 2011 Research Report http://hdl.handle.net/10356/45737 en 48 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Engineering::Environmental engineering::Waste management
spellingShingle DRNTU::Engineering::Environmental engineering::Waste management
Leong, Yuan Shan.
Anaerobic co-digestion of food waste and brown water
description Anaerobic digestion technology is one of the sustainable approaches to convert wastes into a biogas that provides a renewable energy source to replace the diminishing non-renewable natural resources. This research was mainly to study the performance of anaerobic co-digestion of food waste and brown water at different organic loading ratios. Monitoring parameters include the measurement of pH, volatile solids reduction, chemical oxygen demand (COD), alkalinity, volatile fatty acids (VFA) concentration, biogas composition, methane yield, and methane production rate. The experiments were conducted at a temperature of 35°C. The organic loadings for the anaerobic digestion of food waste and brown water were 0.3gVS/L, 0.5gVS/L, 1.0gVS/L and 2.5gVS/L. Both digestions had shown decreased pH and increased VFA concentration in the initial phase of the digestion. Smaller organic loadings yielded higher methane gas for every gram of VS added to the both systems, while higher organic loadings had higher methane yield per gram of VS or COD removed. 80% of methane yield per VSadded for both digestions had been achieved in the first 10 days, with methane contents in the range of 50-80%. Low pH and VFA accumulation may be the result of inhibition of the methanogens, affecting the methane yield. Food waste yielded lesser methane than brown water, with likelihood of inhibition effects due to high oil content in the food waste. Based on the digestion of food waste and brown water, co-digestion was conducted with the organic loading ratios of 0.5:0.5, 0.3:0.7, 0.7:0.3 and 1:1 brown water versus food waste. Either combinations of 0.3gVS/L of food waste and 0.7 gVS/L of brown water or 0.7gVS/L of food waste and 0.3 gVS/L of brown water yielded halved as much as the digestion of the substrates individually. As for the 0.5gVS/L and 1.0gVS/L loadings, co-digestion also yielded lesser methane than individual digestion. The results suggest that co-digestion failed to improve methane production rates and that the anaerobic digestion of food waste and brown water are incompatible. It could be due to microbial interactions of the microorganisms from both substrates when they were mixed such as amensalism where either one microbial population caused inhibitory effects to the other population, or due to chemical reactions of fermentation by-products of food waste and brown water digestion. Further studies recommended include the explicit study on the microbial interactions of food waste and brown water in municipal sewage sludge, and the chemical reactions pathway of co-digestion of food waste and brown water.
author2 School of Civil and Environmental Engineering
author_facet School of Civil and Environmental Engineering
Leong, Yuan Shan.
format Research Report
author Leong, Yuan Shan.
author_sort Leong, Yuan Shan.
title Anaerobic co-digestion of food waste and brown water
title_short Anaerobic co-digestion of food waste and brown water
title_full Anaerobic co-digestion of food waste and brown water
title_fullStr Anaerobic co-digestion of food waste and brown water
title_full_unstemmed Anaerobic co-digestion of food waste and brown water
title_sort anaerobic co-digestion of food waste and brown water
publishDate 2011
url http://hdl.handle.net/10356/45737
_version_ 1759852931890282496