Introduction:
As major nations like China, the US, and India continue to experience increased economic development and urbanization, our increased consumption of earth's natural resources and increased production of consumer-base waste is becoming more and more a critical issue. The essence of this issue lies in the population dynamics of our exponential growth, as shown by this chart by the Population Reference Bureau in Washington:
Interestingly, this shows a peak and suggests an eventual downfall. Humans have been changing, using, and disposing of earth’s natural resources for centuries.
This map, based on data from the Laboratory for Anthropogenic Landscape Ecology, shows changes in ‘Anthromes’ or anthropogenic biomes modeled from 1700-2000. The vast orange areas illustrate the increased development of the natural world:
Through our development we have not only altered our natural environment but we have disrupted, destroyed, and disposed of much of it. This map shows the progression of our development from the 1700s on the right to 2000 on the left and the overall change again above:
As a world leader with rapid urbanization and economic development, China’s growing population is creating serious urban waste issues. Municipal Solid Waste (MSW) grows by more than 10% each year and is totals more than 1000 pounds per person each year. This graph shows the rapid development of China over the last three centuries leading to it present condition of vast villages and settlements and numerous large urban centers:
Before the 1990s, formal collection and treatment of municipal solid waste in China was at a rate of less than 5%. Since then China has been making significant efforts in improving its standards and performance. Now over 80% of waste generated in China is landfilled, but less than 10% conform to US standards, and almost 50% are open dumps.
Collected waste is often mixed, making recycling and treatment efficiency difficult. Also, large amounts of waste generated outside of the urban centers often fails to reach the proper landfills and ultimately ends in uncontrolled local dumps or elsewhere on the way.
While countries like the US, Australia, and South Korea capture and store over half of their waste in controlled landfills, over half of the waste in other countries like China, Turkey, and other developing countries ends up in uncontrolled landfills or is dumped illegally. This map shows some of the top annual producers of waste including the US, Mexico, Australia, Brazil, Argentina, China, and others:
However, waste collection, transfer, and treatment standards and efficiency has been rapidly improving in recent times. Statistics show that municipal solid waste treatment plants increased their total average capacities from 193,000 tons/year to 257,000 tons/year within just the first 5 years of the past decade.
Gases emitted from landfills can have a serious impact on local environments as well as global climate change. Methane accounts for about 60% of this landfill gas and CO2 about 40%. Although CO2 remains in the atmosphere much longer than methane, methane contributes much more to the greenhouse effect.
Improving landfill technologies and standards is especially important for reducing greenhouse emissions and improving air quality, but also important for reducing the mounting problems of waste scattering, toxic wastewater seepage and runoff, groundwater contamination, odors, and many other environmental hazards. Our populations are not going to get any smaller and neither are our mounting trash problems.
As I became aware of these underlying issues in consumption and waste that have been developing over the centuries and will continue to plague us in the future led, I started to look into solutions, to at least prolong the inevitable. Coupled with China’s recent development and consumption has been efforts in reducing their impact and increasing their sustainability. I had done research on the technologies they are developing and am convinced that there is promising hope, but needed to determine more about by whom and where the effort should be made. I decided to focus on Xi'an in the Shaanxi Province of Chine:
Methods:
To do this, I gathered extensive data and performed spatial analysis on my findings. I used raster reclassifications and map algebra for the first few anthrome maps. I reclassified all of the anthrome cells based on the following impacts or levels of development:
Urban: 5
Mixed Settlements: 4
Villages: 3
Crop Land: 2
Rangelands: 1
Barren and Woodlands: 0
With this newly reclassified data, I used the raster calculator with the command of ‘reclass2000’ – ‘reclass1700’. I took the resulting values of -4 to 5 and reclassified them based on the following:
Became Less Developed: (-4) – (-1)
Remained the Same: (-.99) – 0
Became More Developed: 0 – 3
Became Much More Developed: 3.01 – 5
To make the MSW map I used data from a LFGTE company called Veolia Environmental Services and created a simple xcel spreadsheet, joined it with a world countries layer from the UCLA GIS data share, and created the appropriate symbology.
Next I used data from the WWF biomes to create a map displaying the local biomes around Xi’an in the Shaanxi area. I created some additions to the map with the drawing tool, included a symbol based on the location of Xi’an, and performed basic clip functions.
Similar methods were used to create the map on the Xi’an focus area but data from the UCLA GIS data share was used.
I created the map locating existing power generating landfills in China by performing select by attribute queries using data from an online Global Administrative Areas forum and matching cities with the cities in the names of found LFGTE sites.
For the suitability maps I used the same GAA data as well as a DEM and population grid from ESRI. I first converted the DEM to a grid of slope. Then reclassified the slope and population grids. I classified the flat areas and most populated areas as the highest. This allowed me to add them using single output math algebra. I reclassified the results again and then converted it to a shapefile. I clipped the final combined shapefile with the Xi’an city limit polygon.
I used the same data and layers for the Shaanxi region site suitability but selected by attributes for values > 3 which were areas of high population and low slope.
Results:
Through my methods and research I came to realize that there is great potential within China to develop and implement successful treatment technologies. I focused on the feasibility of the Xi’an area within the Shaanxi province.
Xi’an is a leader in innovation and on the forefront of China’s economic and urban development. It has also made significant efforts to do so sustainably and environmentally consciously. Based on carbon emissions and urban development, Xi’an was as the ranked by the National Bureau of Economic Research as the 44th ‘most green’ city out of 74 major Chinese cites in 2006.
The Sanitation Bureau in Xi’an collects about 1,500 tons/day of domestic, commercial, industrial, and construction waste. About 80% of this waste is taken to the Jian Cun Gao landfill. In addition to Xi’an’s Sanmincun Waste Transfer Station, 100 small-scale waste transfer stations have been built around the city to improve collection measures. In 2009, coverage of waste collection increased to 99% in some areas of the city.
These measures were part of Xi’an’s efforts to obtain the status of a “National Hygienic City”, which it did in 2008. The rest of China’s is facing similar issues with waste accumulation and national policies and efforts are also aimed at increasing the capture amounts and efficiency.
However, while these large scale and rapidly growing urban centers do need to increase their amount of waste capture and treatment, it is important what is done with this increasing volume of waste. There are many different types of treatment processes and procedures, but those that reuse the incoming waste are the most efficient.
The following collected data summarizes some of the existing landfill gas-to-energy (LFGTE) plants and technology in China:
Guangzhou Xingfeng LFGTE Plant:
Energy Capacity: 9 MW
Energy Production: 200 MWh/day
Future Capacity: 13 MW
Treats 5000 cubic meters/hour of landfill gas
Largest landfill gas-to-energy plant in China.
Hangzhou Tianziling LFGTE Plant:
Energy Production: 15,700 KWh/year
Gas treated to date: 116.5 million cubic meters
Xi’an Jiang Cun Gao LFGTE Plant:
Energy Capacity: 7,500 KW
Energy Production: 40,000 KWh/year
CO2 Reductions: 108,000 tons/year
The only operating landfill in Xi’an city and has the second largest energy capacity in
China.
Shanghai Laogang LFGTE Plant:
Energy Capacity: 15 MW
Energy Production: 22,700 MWh/year
Gas Treated To Date: 19.42 million cubic meters
Guangzhou Datianshan LFGTE Plant:
Energy Capacity: 1 1,060 KWh unit
Energy Production: 6,900 MWh/year
Foshan Gaoming LFGTE Plant:
Capacity: 1,936 tons/day
Area: 23,980,000 cubic meters
Average Depth: 100 meters
Future Energy Capacity: 6.5 MW
Horizontal and vertical gas extraction pipes optimize gas-to-energy efficiency allowing its 8 generators to efficiently supply the local electricity grid.
Hong Kong S.E.N.T. LFGTE Plant:
Energy Production: 12,203 MWh
Capacity: 49,000,000 cubic meters
Internal Thermal Energy Production: 38,430 MWh
Close to the urban center of Hong Kong, it receives 39% of the Hong Kong’s waste.
Beijing Asuwei LFGTE Plant:
Energy Capacity: 2,700 KW
Energy Production: 20 Mil KWh/year
CO2 Reductions: 100,000 tons/year
Energy Supply: 17,000 homes/year
Methane Reductions: 13 million cubic meters/year
Suzhou LFGTE Plant:
Energy Capacity: 1.25 MW/unit with 4 units
Directly into the Suzhou City local power grid.
Each of these and more are marked in green on this map.
Accessing the energy in the landfill gas is the best way to do this. As waste decomposes large amounts of heat is given off. Energy from this heat can be stored and used to produce power. Fuel can also be generated by processing certain components of municipal waste that are highly petroleum based. This not only accesses the energy stored in the waste but also diverts it from ending up in the ground or on the street for years and years to come. The following table from the Coral Reef Alliance puts some perspective on what ends up in landfills:
| Waste | Time To Decompose |
| Notebook paper | 3 months |
| Comic book | 6 months |
| Wool mitten | 1 year |
| Cardboard milk carton | 5 years |
| Wooden baseball bat | 20 years |
| Leather baseball glove | 40 years |
| Steel can | 100 years |
| Aluminum soda can | 350 years |
| Plastic sandwich bag | 400 years |
| Plastic six-pack ring | 450 years |
| Polystyrene foam cup | Maybe never |
| Car tire | Maybe never |
| Glass bottle | Maybe never |
Conclusion:
Estimates account landfills for 12% of global methane emissions, coal for 6%, and oil and gas for another 18%. In developing countries, landfills can contribute up to 40% of their methane emissions. Using LFGTE technologies will reduce each of these three sources of emissions. However, as previously mentioned, although these methane emissions have the potential to influence climate change, landfills pose a plethora of other serious environmental hazards as well. As inputs to landfills increase, solutions to these issues need to also. Converting landfill gas to energy, recycling and gasifying rubbers and plastics and other petroleum based waste, and properly incinerating waste are essential techniques. Based on its population quality and quantity, as well as topography, Xi’an is a prime place to increase the momentum of such practices.
This map displays that based on population density and slope, within Shaanxi the Xi'an city limits is near many suitable sites.
References:
Xi’an power demand: http://www.cbw.com/business/invest/xian/index.htm
U.S. EPA, Global Anthropogenic Emissions of Non-CO2
Greenhouse Gases: 1990-2020 (EPA Report 430-R-06-003)
‘A Winning Combination of Renewable Clean Power with Greenhouse Gas (GHG) Reduction’. Hong Sima, Jan C. Hutwelker, Samuel A. Dean, David R. Horvath
Landfill Gas to Energy (LFGTE) Project
Landfill Gas to Energy (LFGTE) Project
‘Putting People in the Map: Anthropogenic
Biomes of the World’. E Errllee CC Ellis and Naavviinn Ramankuty
Front Ecol Environ 2008; 6(8): 439–447.
‘Our Presence & Future’. Joe A. Zorn. Veolia Environmental Services In China.
Landfill Gas to Energy Conversion Project, China South Pole Carbon Asset Management Ltd http://www.southpolecarbon.com/_marketing/259LFG_China.pdf
‘How Biodegradable is Your Trash?’ Coral Reef Alliance http://www.coral.org/node/3916
‘Summary Evaluation’ conducted by: Foundation for Advanced Studies on International Development (FASID) Report date: June 2009
‘Brief Introduction to Shaanxi Province and its Environment Protection’
Shaanxi environment protection 2004
http://www.snepb.gov.cn/en/menu.html
Shaanxi environment protection 2004
http://www.snepb.gov.cn/en/menu.html
The Greenness of China: Household Carbon Dioxide Emissions and Urban Development
Siqi Zheng, Rui Wang, Edward L. Glaeser, and Matthew E. Kahn
NBER Working Paper No. 15621
December 2009
JEL No. Q5
China ShapeFiles extracted from GADM version 1.0, March 2009
Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License
http://www.gadm.org
Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License
http://www.gadm.org
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