‘Segregation’ at source is the first step in disposal of waste. The wastes should be segregated at source as different types of waste need to be disposed of in different manner. It is more profitable and economical to segregate the waste at the source. In residential areas, the waste can be separated by using different coloured bins in which the residents can throw the waste accordingly. For example, blue coloured bins can be used for non-biodegradable waste and green coloured for biodegradable waste.
The segregation of different types of solid waste at the location where they are generated. The number and types of categories into which wastes are divided usually depends on the collection system used and the final destination of the wastes. The most common reason for separating wastes at the source is for recycling. Recyclables that are segregated from other trash are usually cleaner and easier to process. Yard wastes are often separated so they may be composted or used as mulch. Some experimental municipal recycling projects also require homeowners to separate household compostable such as food scraps, coffee grounds, bones, and disposable diapers. Some studies suggest that as much as 30% of household waste may be compostable; another 40% may be recyclable.
Separate collection of household trash, recyclables, and yard waste is gaining popularity in the United States. In some communities source separation is mandated, while in others it is voluntary. Many cities provide residents with recycling bins to be filled with recyclables and placed next to garbage cans on collection day. Source-separated yard waste is usually placed in plastic bags or bundled if it is bulky, like tree trimmings. In areas where curbside collection of recyclables and yard waste is not available, residents often take these source-separated wastes to drop-off centers, or sell recyclables to buy-back facilities. For source-separated recycling programs to be successful, citizen participation is essential. Incentives to increase participation, such as reduced trash collection charges for recyclers, are sometimes implemented.
Household recyclables that are source separated from trash can either be commingled or segregated into individual containers for each material. Commingled recyclables are eventually separated manually, mechanically, or by some combination of both at transfer stations or materials recovery facilities. In some cases, commingled recyclables are manually separated at the curbside by the collection crew. Recyclables that residents have separated into individual containers are usually collected in trucks with compartments for each material. The collected materials are then processed further at materials-recovery facilities or other types of recycling plants.
Many businesses also separate their solid wastes. This can be as simple as placing recycling bins next to soda-vending machines in employee cafeterias or more complex separation systems on assembly lines. One of the most prevalent wastes from the commercial sector is corrugated cardboard (13% of municipal solid waste generated). Once it becomes contaminated by other wastes, it may not be suitable for recycling. Some businesses find it easier and more economical to separate and bale corrugated cardboard for recycling because this can reduce their waste-disposal costs.
Source-separation programs can reduce the undesirable effects of landfills or incinerators. For instance, batteries and household chemicals can increase the toxicity of landfill leachate, air emissions from incinerators, and incinerator ash. In addition, some potentially noncombustible wastes, such as glass, can reduce the efficiency of incinerators. Reducing the volume of residual ash is another incentive for diverting wastes from incineration.
Recyclables and special wastes can be retrieve from the waste stream without source separation programs. Many communities find it more convenient or economical to separate wastes after collection. In these programs, recyclables and special wastes are manually or mechanically separated at transfer stations or materials-recovery facilities. Separating recyclables in this way may require more labor and higher energy costs, but it’s more convenient for residents since it requires no extra effort beyond regular trash disposal procedures.
Source separation may be only one part of an overall community recycling program. These, in turn, are components of more comprehensive waste-management strategies. To reduce the environmental impact of waste disposal, the Environmental Protection Agency (EPA) encourages communities to develop strategies to decrease landfill use and lower the risks and inefficiencies of incineration. Waste reduction and recycling are considered to be the most environmentally beneficial methods to manage waste.