Waste Management Sunny Mistry Rensselaer Polytechnic Institute Solid and Hazardous Waste Prevention and Control Engineering Spring 2014 MANE-6960
Introduction: Modern waste management strategies have been influenced by the significant increase of waste generated by humans. 1 Federal, state and local governments have developed regulations in order to reduce the total amount of solid waste and increase recyclable waste. There are an estimated 136,000 garbage trucks, 12,000 transfer vehicles and 31,000 dedicated recycling vehicles to haul away America s garbage. These vehicles travel approximately 25,000 miles every year, and consume less than 3 miles per gallon. This consumption rate yields 8,600 gallons of gas per year. Furthermore, these vehicles are over 10 years old, and account for approximately 40% of the total amount of garbage trucks out there. 2 This research paper will go into the methods of transportation of solid waste from the household to the disposal site, methods that increase the efficiencies of the trucks, and a discussion of the transportation problems and solutions. Background: Based on the graph shown below in Figure 1, it can be inferred that the total municipal solid waste generation has been increasing over the past 45 years. The last 5 years have shown a slight drop in the total municipal waste generation. Also shown in Figure 1 is the per capita generation rate, which also has been increasing since 1960 to 2005, and since has declined slightly. This shows that humans are taking more caution before throwing waste out. 1 "Municipal Solid Waste." EPA. Environmental Protection Agency, 28 Feb. 2014. Web. Apr. 2014. 2 "INFORM - Fact Sheet - Greening Garbage Trucks Fact Sheet." INFORM - Fact Sheet - Greening Garbage Trucks Fact Sheet. N.p., 2009. Web. Apr. 2014. 2
Figure 1: Municipal Waste Generation Rates From 1960 to 2012 3 Figure 2: Total Municipal Waste Generation Broken Down By Material 4 3 "Municipal Solid Waste." EPA. Environmental Protection Agency, 28 Feb. 2014. Web. Apr. 2014. 3
The average person produces approximately 4.5 lbs of solid waste per day in the United States based on data gathered from 2008. 5 Figure 2 shows the breakdown of total municipal solid waste generation by material. The waste generated is collected in containers, rolled out to the street every week in most residential households and in most cases, forgotten about. The solid waste collected from households is transported to landfills, waste transfer stations or disposal sites. In some instances, the solid waste is transported via barge to another landfill. Transportation efficiency plays a big role in transferring the solid waste from the household curb to the disposal site and from landfill to landfill. Transporting heavy compacted solid waste can be inefficient for the vehicles. Transportation Problems: Inefficiencies in transportation from trucks are significant. Refuse trucks are one of the most inefficient vehicles on the roads today with fuel consumption of approximately 2.8 miles per gallon of gas. 6 Diesel trucks also emit over 40 toxic substances in exhaust fumes and fine particulates, many of which are known carcinogens and can also induce asthma attacks. 7 Finally, most refuse trucks have been on the road for more than 10 years. Due to the old age of the trucks, pollution controls have been degrading which in turn allows smaller particles to be emitted into the air creating a hazardous condition for the public. 8 Additionally, traffic is another contender that plays a role in impacting the environment. In most cases, refuse trucks are routed through less congested areas that allow the truck to be as efficient as possible. 4 "Municipal Solid Waste." EPA. Environmental Protection Agency, 28 Feb. 2014. Web. Apr. 2014. 5 "Waste and Recycling Facts." Clean Air Council. Waste and Recycling Facts, n.d. Web. Apr. 2014. 6 Mandell, Stephanie. "Natural Gas Refuse Trucks: Driving Change in New York City." Informinc.org. INFORM Strategies for a Better Environment, Apr. 2006. Web. 7 Mandell, Stephanie. "Natural Gas Refuse Trucks: Driving Change in New York City." Informinc.org. INFORM Strategies for a Better Environment, Apr. 2006. Web. 8 Mandell, Stephanie. "Natural Gas Refuse Trucks: Driving Change in New York City." Informinc.org. INFORM Strategies for a Better Environment, Apr. 2006. Web. 4
In many cases, this is an effective way to increase efficiency, although in some cases local roads and bridges restrict gross vehicle weight or restrict individual axle weights. In addition, public health also plays a part in refuse truck travel. Refuse trucks traveling through residential areas have to be mindful with truck noise (backup alarms, compactors, engine noise, hydraulic arm noise, etc.). 9 Table 1: Natural Gas vs Diesel Garage Trucks Table 1, above, shows the reduction of pollutants with the use of natural gas in lieu of diesel garbage trucks. Natural gas trucks also run quieter and require less overall maintenance when compared diesel garbage trucks. 10 Another factor is the locations of transfer stations in relation to the trucking routes. Transfer stations need to be located appropriately to minimize unnecessary travel of the refuse trucks to reduce inefficiencies in the truck. Furthermore, transfer stations aid by being able to consolidate smaller loads from smaller trucks into larger vehicles and transporting them off site. On the other hand, bottlenecks 9 "Waste Transfer Stations: A Manual for Decision-Making." United States Environmental Protection Agency. EPA, June 2002. Web. 10 "INFORM - Fact Sheet - Greening Garbage Trucks Fact Sheet." INFORM - Fact Sheet - Greening Garbage Trucks Fact Sheet. N.p., 2009. Web. Apr. 2014. 5
can occur at the transfer station further creating inefficiencies in the refuse trucks. Correctly routing and timing can reduce the overall total wastefulness from the refuse truck. 11 Transportation Solutions: Companies like Waste Management recognized concerns with truck routing. From this, the company invested in development of its IT infrastructure and created a web based solution that can manage routes for the trucks. Waste Management provided the software development company, Institute of Information Technology, Inc. (IIT), three objectives. 12 The objectives are listed below. 1. Route reduction yielding a cost savings 2. Workload balance across days of the week (Reducing/optimizing routing) 3. Adherence to business constraints IIT took the objectives one step further. The software also included: 1. Turn restriction 2. Penalties 3. Speed limits 4. Adherence to side of street for residential routes 5. Four hour processing time restriction 11 "Waste Transfer Stations: A Manual for Decision-Making." United States Environmental Protection Agency. EPA, June 2002. Web. 12 Sahoo, Surya, Seongbae Kim, Byung-In Kim, Bob Kraas, and Alexander Popov, Jr. "Routing Optimization for Waste Management." Interfaces. INFORMs, Jan.-Feb. 2005. Web. 6
Figure 2: Shows a Before (a) and After (b) Software Implementation 13 The software WasteRoute was developed and deployed across the United States in March in 2003. 14 Figure 2, above, shows the benefits of using the software. The software modified the existing route (Figure 2a) by removing one route (represented in the figure via a polygon) and developed the after (Figure 2b) which increased the productivity of the area from 57.06 yards per hour to 63.10 yards per hours. This reduction helps save cost and time. 15. Utilizing this software Waste Management saved approximately $18 million at the end of the first year (March December 2003). For 2004, Waste Management saved approximately $44 million, due to additional software deployment and further reduction in routes. 16 13 Kim, Byung-In, Seongbae Kim, and Surya Sahoo. "Waste Collection Vehicle Routing Problem With Time Windows." Www.sciencedirect.com. Science Direct, 21 Nov. 2005. Web. 14 Kim, Byung-In, Seongbae Kim, and Surya Sahoo. "Waste Collection Vehicle Routing Problem With Time Windows." Www.sciencedirect.com. Science Direct, 21 Nov. 2005. Web. 15 Sahoo, Surya, Seongbae Kim, Byung-In Kim, Bob Kraas, and Alexander Popov, Jr. "Routing Optimization for Waste Management." Interfaces. INFORMs, Jan.-Feb. 2005. Web. 16 Kim, Byung-In, Seongbae Kim, and Surya Sahoo. "Waste Collection Vehicle Routing Problem With Time Windows." Www.sciencedirect.com. Science Direct, 21 Nov. 2005. Web. 7
Table 1: Waste Benchmark Problem Set Table 2 was based on existing tabulated data for current processes and routes. This table provides vehicle capacity, total yards allowed per vehicle per day, total number of stops allowed for a vehicle per day, lunch break time in seconds, default speed (MPH) and stop data. The data was used to aid in the development the waste management software. The government could further help the reduction in pollutants by providing incentives to corporations in the following ways: 1. Economic incentives for vehicle procurement 2. Infrastructure development 3. Alternative fuel usage Furthermore, the government can implement stronger regulatory measure, which will force companies into moving away from the traditional diesel garbage trucks, and moving toward natural gas fueled trucks. 17 17 "INFORM - Fact Sheet - Greening Garbage Trucks Fact Sheet." INFORM - Fact Sheet - Greening Garbage Trucks Fact Sheet. N.p., 2009. Web. Apr. 2014. 8
Other Potential Solutions: Future methods of increasing the efficiency of garbage trucks can include incorporation of hybrid vehicles as listed below. Additionally, development of trucks that meet the requirements of the industry and provide added benefits compared to the gas fueled garbage trucks. The continued development of these alternative fuel sources will allow waste management companies to further increase profits. Depending on the fuel source used 80 million, Americans will be breathing cleaner air everyday as a result from the reduction in emissions such as particulate matter and nitrogen oxide from the garbage truck. 18 1. Fuel cell 2. Landfill gas 3. Biodiesel 4. Propane 5. Hydrogen In conclusion, with the increase of total municipal solid waste increasing, the transportation problem has been evaluated and methods have been put into place to reduce the overall impacts. Transportation creates other problems, like for example, the addition of toxic exhaust substances into the atmosphere furthering the health risk for the public. Companies like ITT have developed intricate algorithms that increase the overall efficiency of the trucking routes, which produces a lot of financial savings. Furthermore, corporations can look at adding more efficient vehicles into the fleet, which will have an upfront cost but provide benefits in the long run. In the end, waste management corporations 18 "INFORM - Fact Sheet - Greening Garbage Trucks Fact Sheet." INFORM - Fact Sheet - Greening Garbage Trucks Fact Sheet. N.p., 2009. Web. Apr. 2014. 9
are going in the right directions by looking at new methods to increase efficiency of trucks. The implantation of these new methods can significantly benefit waste management corporations. 10
Works Cited "INFORM - Fact Sheet - Greening Garbage Trucks Fact Sheet." INFORM - Fact Sheet - Greening Garbage Trucks Fact Sheet. N.p., 2009. Web. Apr. 2014 Kim, Byung-In, Seongbae Kim, and Surya Sahoo. "Waste Collection Vehicle Routing Problem With Time Windows." Www.sciencedirect.com. Science Direct, 21 Nov. 2005. Web. Mandell, Stephanie. "Natural Gas Refuse Trucks: Driving Change in New York City." Informinc.org. INFORM Strategies for a Better Environment, Apr. 2006. Web. "Municipal Solid Waste." EPA. Environmental Protection Agency, 28 Feb. 2014. Web. Apr. 2014. Sahoo, Surya, Seongbae Kim, Byung-In Kim, Bob Kraas, and Alexander Popov, Jr. "Routing Optimization for Waste Management." Interfaces. INFORMs, Jan.-Feb. 2005. Web. "Waste and Recycling Facts." Clean Air Council. Waste and Recycling Facts, n.d. Web. Apr. 2014. "Waste Transfer Stations: A Manual for Decision-Making." United States Environmental Protection Agency. EPA, June 2002. Web. 11