Waste Management: Solutions and Services for Businesses

Incineration 

Incineration entails a controlled thermal procedure to reduce combustible solid waste to yield water vapor, carbon dioxide, sulphur oxide, oxides of nitrogen and noncombustible residues that can be land-filled sustainably or processed further. It involves burning solid waste at high temperatures (over 1000 o C) in oxygen presence to eradicate odors and to facilitate complete combustion. Incineration occurs through a series of stages in the main process (Worrell, Vesilind & Ludwig, 2017). 

Advantages 

Solid waste weight and volume is reduced to a portion of the original size, no need for lasting residence due to immediate waste reduction, no need to transport waste as incineration can occur on site, effective air discharge management leads to a reduced environmental effect, produces sterile or putrescible ash residue, can be enhanced to eliminate more harmful waste products effectively and completely, a small area for disposal is required as opposed to land burial, and energy utilization or sale can be used to offset operational costs through heat recovery methods. 

Disadvantages 

High capital cost, requires skilled operators, some waste products like demolition and construction wastes cannot be incinerated, the incineration process requires supplemental fuel for process initiation and maintenance, concerns regarding the production of harmful emissions such as furan and dioxin, the final solid residue after incineration is disposed of on land, which can adversely affect the environment due to the presence of metals such as cadmium and lead; dioxins are emitted when substances with chloride such as polyvinyl chloride are incinerated, and the incineration process can lead to adverse health effects such as damaged immune system, thyroid problems and damage to the nervous system. 

Incineration is uneconomical due to high costs of related equipment to control air pollution and to treat solid ash before disposal to land. 

The Process 

Incineration entails an oxidation procedure in which organic products react with oxygen to release heat. Four steps are involved in the main process to ensure thermal destruction of solid waste. They include drying, volatilization, fixed carbon combustion, and solids’ char burnout. These steps are followed by the secondary process (Worrell, Vesilind & Ludwig, 2017). Drying involves the initial heating to drive off moisture from the solid waste in which the products are heated past the evaporation temperature of water. Volatilization entails diffusion of gases and vapors out of the waste as the temperature rises. Fixed carbon combustion involves the in-place oxidation of combustible solids left following volatilization. Burnout of solid char entails the final combustion of char left after the fixed carbon combustion, and the cooling and consolidation of the bottom ass, which is the final product of the primary process. 

The secondary process is the final process to destroy solid waste under high temperature to ensure that all the unburned particulates, vapors and gases from the main process are destroyed. 

Pyrolysis 

Pyrolysis involves the endothermic thermochemical decomposition of organic substances in the absence of oxygen or with a limited oxygen supply (Worrell, Vesilind & Ludwig, 2017). The process entails the irreversible and simultaneous conversion of physical phase and chemical composition of waste products. The restricted oxygen supply offers the combustion energy that the pyrolysis process requires at the expense of end products, which include solid char, liquids and syngas. Pyrolysis occurs at temperatures lower than 700 o C (Reddy, 2018). 

Advantages 

The thermal distress of the process is less intense than in incineration due to low decomposition temperature, fewer air emissions as decomposition occur in a reduced environment with limited oxygen supply, metals in the final waste product are retained better and are valuable since they are not oxidized during pyrolysis, it is simple to clean the resulting gas since no ash emerges from the burning of the pyrolysis gas, the original waste weight and volume is highly decreased compared to incineration, does not form furans and dioxins, suited for waste products with high volatile content like plastic wastes, produces carbon dioxide neutral energy, and it is possible to retain or distill hydrochloric acid from the solid residue. 

Disadvantages 

Solid waste must be separated or shredded before starting the process to ensure that the feed and the transport systems are not blocked, which increase the cost of installing and operating the process; the produced liquids contain carcinogenic and toxic substances, requires further treatment before disposal of final products, require cost-intensive facilities to clean wastewater and gases, presence of heavy metals in char, and requires supply of backup fuel. 

Pyrolysis is an economically efficient solid waste disposal technique as it converts waste disposal and recycling into electrical and heat energy. The technique leads to substantial reductions of harmful emissions, which are higher in the traditional incineration technique. 

The Process 

The pyrolysis process involves four stages, which include pre-processing, drying, the pyrolysis process, and gasification. During the pre-processing stage, solid waste is mixed and shredded before being moved into a pyrolysis reactor for the drying stage. The reactor dries the waste to a specific moisture level. Then, the pyrolysis process decomposes substances from the reactor into simple components under high temperature without oxygen. During this stage, carbon dioxide, H2O, and H2S are decomposed. Then, CH4 is separated from aliphatic substances, which leads to the formation of pyrolysis coke or solid residue. Then, the gasification stage converts the solid residue into gas under steam or oxygen influence (Reddy, 2018). 

The Laws or Standards that Factor into the Decision 

The applicable federal regulations and standards to municipal solid waste management include the Clean Air Act that establishes national emission standards for solid waste management plants and the Maximum Achievable Control Technology (MACT) principles that limits air toxic emissions. The Resource Conservation and Recovery Act require states and local jurisdictions to adopt strict laws as those required by the municipal solid waste incinerator performance guidelines and standards. 

How the Decision will affect the Community Population 

Disposing of solid waste in regular landfills is dangerous and leads to the seepage of unfavorable volumes of harmful substances into the ground, which will eventually enter into the natural hydrological cycle and harm the environment and people. The decision to treat solid waste using the latest technologies is beneficial because these technologies will stabilize solid waste and dispose of them safely. These technologies also produce recyclable products that can be reclaimed or made into other products. Pyrolysis, for example, reduces the volume of solid waste while also generating energy. Toxic air emissions can be controlled using air pollution technologies. The decision to select a solid waste management technology will ensure that people live in a clean environment. 

Recommendation and Rationale to the City 

The city can use the pyrolysis technique to manage its municipal solid waste. Pyrolysis is valuable because it converts solid waste into different energy forms. The syngas that pyrolysis produces can be converted into valuable products such as fertilizers, chemicals and transportation fuels. Pyrolysis is also cleaner compared to incineration. For example, the produced syngas can be cleaned and processed before being used further (Reddy, 2018). Pyrolysis does not form furans and dioxins as it does not use oxygen. Solid ash from pyrolysis is also valuable as it can be converted into usable products. 

References 

Reddy, P. J. (2018).  Energy Recovery from Municipal Solid Waste by Thermal Conversion Technologies . S.l.: CRC Press. 

Worrell, W. A., Vesilind, P. A., & Ludwig, C. (2017).  Solid waste engineering: A global perspective . Boston (MA): Cengage Learning