Solid Waste Management Systems
Waste management systems cover processes of collection, temporal storage, internal transportation, treating, and finally the goal of garbage disposal or remains generated from garbage management procedures (Douncet & Gilyeat 1).
Other common terms related to waste management systems include; waste handling, waste storage, waste processing and waste treatment. Waste handling comprises all the processes concerned with the transportation from the point of generation. Waste handling systems and equipment generally include chutes, transportation vehicles and carts.
Waste storage comprises all the processes of containing generated waste in controlled places, after collection and transport, before handling, recycling, treatment or final disposal.
Waste storage systems vary based on the type of waste, constituents, properties, mode of collection and transportation. Bulky wastes can be stored in pits o silos, while bags, drums or containers are used for containing smaller wastes. Waste processing refers to processes that alter physical properties, shape, size or consistency.
Common systems and equipment used in waste processing comprise compactors, shredders, escapsulators, extruders, crushers, pulpers, pulverizers, baggers and dewatering equipment.
Solid waste management deals with all types of refuse ranging from municipal waste management, recycling programs, composts, and incinerators.
The type of waste management systems applied differs based on several factors, including kinds of wastes generated, components, forms, characteristics, amount, and the rate at which they are generated. Waste management systems can range from simple to complex.
Different processes and equipment exist for the management of industrial garbage. The applied devices vary depending on the kinds, amounts, forms, and hazardous components of the garbage.
Solid industrial wastes management varies from simple to complex systems. There are systems for storage, handling and storage. Systems and equipment for handling trash include chutes, carts, elevators, conveyors, vehicles for transportation.
Solid wastes can be classified into any of the following classes namely; putrescibles ( these are wastes generated from houses, animal wastes or agricultural wastes etc), bulky combustibles-wood, cloth and wastes found on streets; bulky noncombustible wastes like metallic items and minerals;
small combustible material (same as bulky combustible, the only difference is the size); non empty cans and bottles; powder and dusts e.g. explosives; sludge; pathological wastes; abandoned automobiles; wastes from construction and demolition; and radiological wastes (Douncet & Gilyeat 12).
Waste Chutes and Handling Systems
A waste chute is generally a system that is fixed for moving garbage from where it is produced or temporarily stored to a central point so that it can be collected, processed, treated or finally disposed.
The National Fire Protection Association (NFPA) regulates construction of waste chutes and their maintenance (Drake 1). NFPA 82, called the “Standard on Incinerators and Waste and Linen Handling Systems and Equipment,” stipulates the minimum requirements for waste chutes that all landlords must adhere to, however other codes also must be taken into account.
Five categories of chutes can be identified namely; general access, gravity types systems; limited access, gravity types systems; pneumatic system; gravity –pneumatic system; and multi-pneumatic loading system. General access, gravity types systems have a vertical passage enclosed inside that allows garbage to flow by gravitational force.
Citizens residing in apartments with this kind of chute cannot access this system. Limited access, gravity types systems are more or less the same as general access, gravity types systems, the only difference is that in the latter entry is limited. Access can be through chute entry doors that are locked or maybe closed service opening space doors.
These types of chutes are mainly found in health facilities. Pneumatic systems make use of air-circulation to move trash from chute openings to a centralized point for collection. They can be installed horizontally, vertically or diagonally, based on blow and the characteristic of making them. They are mostly found in hospitals.
Nonetheless, these chutes can be utilized everywhere-apartments clubs, or restaurants. Gravity-pneumatic system employs gravitational force to connect a receiving compartment that connects to pneumatic chute system.
Multiloading pneumatic system is the same as pneumatic; the difference is that access in the latter uses automatic doors to close. Safety officers should pay great attention in designing and building chute systems. In order to contain fires in buildings, we cannot afford to ignore waste handling systems and chute design.
In case of a fire outbreak, waste chutes can easily act as conduits of fueling fires or conveying smokes in residential apartments or work premises. Moreover, chutes are believed to be garbage storage locations as they can be blocked anytime when in use, hence pose a threat of smoke and fire outbreak.
NFPA has developed standards which are supposed to be followed with respect to constructing chutes, the systems of enclosures, fire dampers, sprinklers, and service openings. All these standards are geared towards one major goal-reducing the chances of fire outbreaks and control of the same.
Fire prevention can minimize the damage to properties, injury, health, and ecological risks of landfill fires. The cost of prevention is generally low compared to the cost of fighting and cleaning up a fire.
In most cases, especially for bigger landfills, fire prevention efforts and measures are mandatory. Proper landfill management is crucial for effective landfill fire prevention methods.
Management procedures comprise of restricting all types of calculated fire, carefully examining and controlling the influx of wastes, compressing wastes buried to thwart hot spots from forming, banning cigarette smoking near or onsite, and finally tightening security measures onsite. Methane gas must be detected and managed at a Landfill site (World Bank).
The emission of methane gas is dangerous not only to the environment but also poses a great health risk to the residents living close to the landfill sites. Methane gas, a highly inflammable gas, can be disaster in waiting.
According Federal Regulations all MSW landfill workers are mandated by law to carefully monitor the levels of methane gas after every four month per year.
In instance where methane gas levels in or near the landfill build up to an explosive state, the landfill worker should take precautionary measures to curb any impeding hazard. They must also put into action a mitigation measures to avert risks of landfill fires (Boulevard 20).
Incineration is a waste management process which uses high temperatures for garbage treatment and disposal. Incinerators that are well constructed and maintained can go a long way in reducing the quantities of solid wastes generated from different sources by over 85 percent, thus huge sums of money could be saved-especially costs of transport and disposal.
Incinerators are commonly used to dispose medical and pathological trash in hospitals, higher institutions of learning, and research centers. A part from destroying biomedical and pathological wastes, they are used to destroy potent and obnoxious wastes. Designing incinerators with heat recovery mechanism can help to cut costs on energy.
For fire prevention, incinerators ensure total garbage treatment, which ultimately minimizes on the costs of storage and risks of fire. In that were designed in the olden days had few enclosures, one compartment where combustion occurred. This reduced the effectiveness and efficiency of incinerators, fueled smoke and contributed to bad smell.
Present day incinerators have systems that are able to meet ever increasing demand for incineration thanks to advances in technology. Adhering to fire safety procedures in designing, construction, operation and maintenance of incinerators is paramount. Incinerators are hazardous.
The safety risks of incinerators comes as a result of handling inflammable wastes, high temperatures in the chambers, highly inflammable gases, hot ashes and availability of fuel and combustion chambers. Therefore incineration safety procedures must be strictly adhered to like setting fire alarm, and having sprinklers.
In addition, fire safety rules like planning the location of incinerators, layout, equipment, wastes flow, operations of the system, and proper maintenance must be strictly followed.
There are various types of technologies used in designing of incinerators. The kind of wastes destroyed by incinerator to some extent determines the type of technology to be used and how the incinerator is designed. Nearly all categories of incinerators are supposed to include design details, the quality of construction, and control parameters, to reduce fire incidences.
Typical solid waste incinerators commonly used in institutions, factories and business premises include; multiple-chamber incinerators; controlled chamber incinerators; and rotary kiln incinerators.
Multiple-chamber incinerators are made of a prime fire chamber and a single or many secondary chambers. This type of incinerator is meant to be operated at extreme incineration air levels-ranging from 200 to 300 percent. Wastes are put in the primary incineration chamber most inflammables found in the gases that escape the first chamber is totally burned in the second chamber.
Multiple chamber incinerators are constructed in line with standards adopted in the 18th century. Today these incinerators are entirely used for combustion of pathological wastes –dead animals. Controlled air incinerators are built based on two combustion stages.
Wastes are loaded in the first combustion chamber-anaerobic combustion. Next, smoke and hot gases from first chamber are burned in the second chamber with excess oxygen. Controlled air incinerators are also known as modular combustors and pyrolytic incinerators.
It believed that majority of the incinerators constructed in the 19th century are controlled air incinerators. The last type of incinerator is the rotary kiln type. It consists of an incineration chamber which is cylindrical, inclined at an angle and revolves on its axis.
Waste is put from one end, and the rotation of the chamber creates turbulent situation for complete waste combustion and allowing the elimination of ash remains on the other end. Fire hazards occur during the process of wastes charging.
This is because process of loading wastes in an incinerator creates an interface between high-temperature burning flames and nearby buildings.
Thus, as aforementioned construction, design system, operation procedures and maintenance must be strictly followed to curb the escape of stray flames and burning material in the process of waste charging or loading. The potential environmental risk of manual loading has led to many countries to ban it.
Waste compactors are the machines that make use of electromechanical hydraulics to minimize the wastes generated and package it in smaller amounts. There are two types of Waste compactors-domestic compacters and industrial compactors.
The two are governed by regulation of NFPA 82. Domestic compactors also referred to as kitchen compactor are designed for residential areas for compacting residential household wastes.
Examples of domestic compactor include under -the counter and movable and can be purchased from convenient stores. This type minimizes fire risk of stored waste by trapping it in a metallic chamber under compaction. In spite of this, they should have the capacity for manual opening to enable waste to easily discard due to a mishap of power in the appliance.
One the other hand, commercial-industrial compactors are mainly used by many household residences as a primary system for treating wastes, and aid in waste handling.
Apart from being used inside houses or put outside, they can be fed to a chute or just hand-fed. Four types of commercial compactors include; bulkhead, extrude, carousel bag packer and container packer. Bulkhead type compacter is mounted on plate.
Once the compacted waste is ready, it can be removed and then a bag placed at the same location and stuffed with a compacted block. But for the extruder compactor, waste is inserted via a cylindrical opening.
Driving force forces the waste to be compressed as passes through the cylinder. In a Carousel bag packer, waste is compressed step by step in containers that are contains bag linings.
The bag rotates enabling each bag to be filled. Lastly, for container packer, waste is compressed in a litter bin. This can be done either manually or by the use of machines. Apart from incinerators, compactors, shredders are also used in managing solid wastes.
Codes, Regulations, and Standards
In order to manage, and dispose industrial wastes properly, an in-depth knowledge and understanding of the characteristics of wastes, different types of technologies and processes, state regulations, codes and standards must be studied carefully.
Important Federal Regulations providing guidelines for waste management and disposal include: Resource Conservation and Recovery Act of 1976 (RCRA), Subtitle C, Hazardous wastes Regulations, 40 CFR, parts 260-265 and 122-124; Toxic Substances Control Act of 1976, 10 CFR; clear Air Act of 1963 (CAA) and Clean Air Act Amendments of 1970 and 1990; Oil Pollution Act of 1961; Federal Water Pollution Control act of 1948; occupational safety and Health Act of 1970 including National Institute of Occupational Safety and Health (NIOSH) and Federal Pesticide Control Act of 1972 (FIFRA Act) (.(Adapted from the handbook on Waste handling and control by Lawrence and Sharon).
The general standards for waste materials and how to manage waste include; NFPA 241 Standard for Safeguarding Construction, Alteration, and Demolition Operations; NFPA 251 Standard Methods of Tests of Fire Resistance of Building Construction and Materials NFPA 252 Standard Methods of Fire Tests of Door Assemblies; NFPA 253 Standard Method of Test for Critical Radiant Flux of Floor Covering Systems Using a Radiant Heat Energy Source; NFPA 255 Standard Method of Test of Surface Burning Characteristics of Building Materials; NFPA 256 Standard Methods of Fire Tests of Roof Coverings; NFPA 257 Standard on Fire Test for Window and Glass Block Assemblies; NFPA 258 Recommended Practice for Determining Smoke Generation of Solid Materials; NFPA 259 Standard Test Method for Potential Heat of Building Materials; NFPA 260 Standard Methods of Tests and Classification System for Cigarette Ignition Resistance of Components of Upholstered Furniture; NFPA 261 Standard Method of Test for Determining Resistance of Mock-Up Upholstered Furniture Material Assemblies to Ignition by Smoldering Cigarettes; NFPA 262 Standard Method of Test for Flame Travel and Smoke of Wires and Cables for Use in Air-Handling Spaces; NFPA 265 Standard Methods of Fire Tests for Evaluating Room Fire Growth Contribution of Textile Coverings on Full Height Panels and Walls; NFPA 266 Standard Method of Test for Fire Characteristics of Upholstered Furniture Exposed to Flaming Ignition Source; NFPA 267 Standard Method of Test for Fire Characteristics of Mattresses and Bedding Assemblies Exposed to Flaming Ignition Source; NFPA 268 Standard Test Method for Determining Ignitibility of Exterior Wall Assemblies Using a Radiant Heat Energy Source; NFPA 269 Standard Test Method for Developing Toxic Potency Data for Use in Fire Hazard Modeling; NFPA 270 Standard Test Method for Measurement of Smoke Obscuration Using a Conical Radiant Source in a Single Closed Chamber; NFPA 271 Standard Method of Test for Heat and Visible Smoke Release Rates for Materials and Products Using an Oxygen Consumption Calorimeter; NFPA 272 Standard Method of Test for Heat and Visible Smoke Release Rates for Upholstered Furniture Components or Composites and Mattresses Using an Oxygen Consumption Calorimeter; NFPA 274 Standard Test Method to Evaluate Fire Performance Characteristics of Pipe Insulation; NFPA 69, Standard on Explosion Prevention Systems; NFPA 430, Code for the storage of liquid and solid oxidizer; NFPA 484, Standard for Combustible Metals; NFPA 654, Standard for the Prevention of Fire and Dust Explosions from the manufacturing, Processing, and Handling of Combustible Particulate Solids; NFPA 13 , Standard for the installation of Sprinkler systems; NFPA 30, flammable and combustible liquid code; NFPA 31, standard or the installation of burning equipments; NFPA 54, National Fuel Gas code; NFPA 58, Liquefied Petroleum Gas Code; NFPA 68, and Standard on Explosion Protection by deflagration Venting (Adapted from NFPA).
Today, solid waste management is a lucrative business accounting for billions of dollars or pounds in most developed countries. Waste collection companies collect tons of refuse per annum and sort it for reprocessing or final disposal.
Many cities across the world demand residents to pay for garbage collection, while those in the countryside have dumpsites and recycling facilities for people to take their rubbish. The main aim is to cut down the amount of garbage blocking the lanes and degrading the environment, overlooking the possibility of waste recycling into important products or just discarded.
Solid waste management systems are centered on designing ecologically friendly methods of disposing wastes. There are various categories of solid waste which are handled by waste management agencies.
First and foremost we have recyclable garbage. These are items that are valuable. Solid waste management consists constructing to use scrap metals and other materials like glass, cans, paper, plastics, and wood.
Second is toxic waste; this kind of garbage poses great risk to the environment; hence it should be disposed carefully. In most first world nations there are stringent guidelines on the management of such wastes.
Some land lords can turn green waste into compost manure and use on their farms. This can improve soil fertility and hence boost food production. Green waste is productive than industrial wastes.
Solid waste is collected in containers of varying sizes -household garbage bins, industrial dumpsites which are filled by persons or companies. Municipal Lorries transport the collected solid waste from streets on a regular basis.
In some countries, Local governments have contracted private waste management companies to recycle, collect and treat the garbage generated from cities and industrial facilities.
Most solid waste management facilities operate, maintain bigger dumpsite, while others burn their waste, using the energy produced by the incinerator to power a recycling plant or sell the electricity to companies that generate power. Waste management must take into consideration to avert possible fire outbreaks.
Fire hazards can start during waste transportation, where it is generated, handling of waste, where it is temporarily stored, treatment and finally disposal.
Therefore, fire safety measures must be taken into account in the design, building, and use of waste handling and treatment systems and equipment, like chutes, incinerators, compactors and shredders, as well as a stricter adherence to all Federal codes, standards and regulations.
Wastes generated from industrial areas differ greatly from the domestic type; hence measures must be taken in the design of such incinerators for proper, safe, and efficient treatment and disposal in conformity with the set standards and complex regulations.
Wastes generated from residences can be turned to useful products. Installing incinerators that are effective and efficient can convert wastes into energy to power cities across the world. Sustainable waste management is the responsibility of each and every stakeholder.
Boulevard, Wilson. Landfill Fires: Their magnitude, characteristics, and mitigation. Virginia: United States Fire Administration National Fire Data Center, 2002. Print
Douncet, Lawrence George, and Gilyeat Sharon. Fire protection handbook Vol 1. 20th Ed. Massachusetts: National Fire Protection Association, 2005.Print.
Drake, Byrne. Trash Chute Requirements. n.d. Web.
NFPA. List of NFPA codes & standards. 2011. Web. <https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards>
World Bank. Urban Solid Waste Management. 2011.Web. <http://web.worldbank.org/WBSITE/EXTERNAL/TOPICS/EXTURBANDEVELOPMENT/EXTUSWM/0,menuPK:463847~pagePK:149018~piPK:149093~theSitePK:463841,00.html>