Data Research and Literature Review
The research to date can be split into two main categories, data samples and journal articles. Data samples we have researched have presented the current aims and objectives provided the by the national waste strategy for Scotland and information on the current waste flow data for each council within Scotland.
Researching journal articles has presented useful acadmic information on various topics within the project, two sample articles will be reviewed here.
Data
National Waste Strategy
The latest national waste strategy publication is a plan designed to improve upon the current waste strategy for 11 areas within Scotland. The specific aims of the strategy are:
· Halt the growth of municipal waste by 2010
· 55% recycling and composting by 2020
· Energy recovery from 14% municipal waste
· Landfill reduction of 90 to 30%
The improvements proposed by the strategy are to be implemented following an investigation into the BPEO and Life Cycle Assessment of each area. The publication promtps the governement to work closely with the local governement executives, waste industry, NGOs and stakeholders.
Waste Data Flow
The Scottish Enviornmental Protection Agency (SEPA) publish a spreadsheet of waste flow data for each local authoriy every three months. The document presents values (in tonnes) for the following data for each authority:
· MSWArising · MSW Landfilled
· MSW Incinerated
· Treated Otherwise
· MSW Recycled/Composted
· BMW Landfilled
The regular collection of data and presentation of the reusls allows the progress towards targets for the reduction of landfill to be closely monitored within each area. Improvements or otherwise can be easily observed when comparing results from one term to another.
Literature Review
Bioconvesion of MSW to Glucose for Bio-Ethanol Production
Li, A; Antizar-Ladislao, B; Khuaisheh, M
This report concerns an investigation into the effectiveness of various pre-hydrolosis treatments to obtain the greatest glucose yield for bio-ethanol production. The treatments under investigation are dilute acid, steam treatment and microwave treatment. The experiment involved typical biodegradable MSW fraction (carrot peelings, potato peelings, grass and newspaper).
The report describes in detail the processes involved within each treatment and allows a comparison of the cellulose yield through each process and from which fraction of MSW.
The report concludes that the potential of producing glucose from waste biomass which can then be used to produce bio-ethanol is great. The best form of pre-treatment is stated as dilute acid hydrolosis followed by steam treatment. Single and multi substrates produced the highest glucose yields with newspaper producing the least. The article suggests that the conversion of MSW to bio-ethanol is a practical and sustainable approach to waste disposal however further research into optimization of the process is required.
Landfill-Gas-to-Energy Projects: Analysis of net Private and Social Benefits
Jaramillo, P; Matthews, S
This report was written regarding a programme designed to promote landfill methane capture within the US. The objectives of the article is to evaluate the private and social benefits of landfill gas to energy projects.
The current situation within the US is outlined in the introduction presenting information regarding the environmental methane emissions and corresponding guidelines for landfill emissions. The number of landfills and the current gas to energy products are provided with a value for the possible capacity of the total number of landfills.
A topic providing a description of the technologies that are most widely used for methane capture and production of energy allows the comparison of the various technologies. The article compares the cost between different electricity generation types with the use of an internal engine appearing most cost effective over a long period of time.
The article describes software created by the outreach programme which estimates the opportunities for gas recovery systems. The software operates by estimating gas production, economic cost-benefit analysis and an estimation of emissions of CO2 and SO2 from coal electricity production. The software allows the user to discover whether a certain project is economically viable or not.
Experimental study on effects of moisture content on combustion characteristics of simulated municipal solid wastes in a fixed bed
Kui, D et al
This article investigates the effects on gas production and temperature of a variable moisture content of MSW within an experimental combustion reactor. The authors consider the application of the findings to China where there is an increasing requirement for a solution to waste disposal and where there is also issues concerning pollutive emissions. The experiment found that emissions of carbon monoxide and carbon dioxide varied inversely with the moisture content of the feedstock with the overall temperature decreasing as the moisture content increased. The highest emissions of CO and CO2 were observed at around the middle value for feedstock moisture content. It was also observed that the concentration of nitrous oxide decreased with an increased moisture content.
The results obtained from the experimental analysis prove that higher moisture contents within a waste incineration feedstock can affect the emissions created from the incineeration process. Controlling the moisture content may allow for a reduction in the adverse gas emissions and an overall increase in process efficiency.
References
1) The National Waste Plan (2003) Scottish Executive; Scottish Environmental Protection Agency
2) Landfill Allowance Scheme data (2007/2008) Scottish Environmental Protection Agency
3) Li, Aiduan; Antizar-Ladislao, B; Khraisheh, M (2007) Bioconversion of Municipal Solids Waste to Glucose for Bio-Ethanol Production; Bioprocess Biosyst Eng; 30:189-196
4) Jaramillo, P; Scott Matthews, H (2005) Landfill-Gas-to-Energy Projects: Analysis of Net Private and Social Benefits; Environmental Science and Technology 39:19
5) Dai, K; Fei, J; Liang, L et al (2008) Experimental Study on Effects of Moisture Content on Combustion Characteristics of Simulated Municipal Solid Wastes in a Fixed Bed; Harbin Institute of Technology
Pictures courtesy of
1) National Waste Strategy Scotland - http://www.sepa.org.uk/nws/guidance/nws_1999.htm
2) SEPA Logo - http://www.sepa.org.uk/
