Solid waste consists of everything we throw away. This can be a dumpster behind a grocery store, your own household garbage can, an office waste bin, or construction waste transferred to a nearby county landfill. This waste can be organic, chemical, or simple materials like plastics or textiles. The RCRA (Resource Conservation and Recovery Act), defines solid waste as “any garbage or refuse, sludge from a wastewater treatment plant, water supply treatment plant, or air pollution control facility and other discarded material, resulting from industrial, commercial, mining, and agricultural operations, and from community activities.”
The RCRA is the public law that creates the framework for the proper management of hazardous and non-hazardous solid waste. These guidelines are used in order to write local regulations for how we manage, store, and dispose of our disposables. For example, 40 CFR 243.200 1(a), in consideration of garbage cans, states: “All solid wastes (or materials which have been separated for the purpose of recycling) shall be stored in such a manner that they do not constitute a fire, health, or safety hazard or provide food or harborage for vectors, and shall be contained or bundled so as not to result in spillage. …Containers shall be maintained in a clean condition so that they do not constitute a nuisance, and to retard the harborage, feeding, and breeding of vectors. When serviced, storage containers should be emptied completely of all solid waste.”
The RCRA also defines how landfills will be located, in order to reduce hazards, and protect the surrounding environment. According to the RCRA, solid waste landfills cannot be located within or near fault lines, wetlands, seismic impact zones, floodplains, or other considerably ‘unstable’ locations. Solid waste landfills are required to be covered with a ‘daily cover’, as described in 40 CFR 258.21. “The owners or operators of all (sanitary landfills) must cover disposed solid waste with six inches of earthen material at the end of each operating day, or at more frequent intervals, if necessary, to control disease vectors, fires, odors, blowing litter, and scavenging.”
Solid waste landfills must also consider the accumulation of leachate and methane gas, both formed within the breakdown of organic and other solid wastes. Leachate and methane can be valuable when collected and reused, but hazardous if allowed to escape into the environment. Leachate can be funneled and collected via filtering materials and a series of pumps and piping connected into the leachate management system. Oftentimes, the next step is to collect it in a leachate pond, which is also lined with an impermeable geotextile to prevent seepage into the environment. Since leachate is so heavily concentrated with toxins and chemicals, a corrosion and chemically resistant liner is required in order to successfully contain the liquid and not degrade over time.
Methane is produced by decaying organic matter and is also the primary component of natural gas. If methane collected from the landfill is recaptured, it can be used or sold in order to generate electricity. Sanitary landfills utilize gas extraction wells to isolate the methane before transporting it to further treatment.
Some solid wastes are sent to incinerators in order to be thermally transformed. The resulting ash and smoke from the waste can have negative impacts on our air and environment, but the process is extremely effective in essentially destroying the physical waste. The RCRA includes specific criteria when considering the design of a waste incinerator in section 40 CFR 240.203 2:
- The types, amounts (by weight and volume), and characteristics of all solid wastes expected to be processed should be determined by survey and analysis. The gross calorific value of the solid wastes to be processed should be determined to serve as a basis for design.
- Resource recovery in the form of heat utilization or direct recovery of materials should be considered in the design.
- The facility should be designed to be compatible with the surrounding area, easy to maintain, and consistent with the land use of the area.
- Employee convenience facilities and plant maintenance facilities should be provided. Adequate lighting should be provided throughout the facility.
- The corrosive and erosive action of once-through and recirculated process waters should be controlled either by treating them or by using materials capable of withstanding the adverse effects of the waters.
- Facility design capacity should consider such items as waste quantity and characteristics, variations in waste generation, equipment downtime, and availability of alternate storage, processing, or disposal capability.
- Facility systems and subsystems should be designed to assure standby capability in the event of breakdown. Provision for standby water and power should also be considered.
