Handling

The proper handling of solid waste is important to minimize its negative effects on the environment and public health. Handling wastes makes resource recovery and disposal processes easy and convenient. It ensures that the environment and its species can thrive. Safe and appropriate handling techniques also ensure that the health of workers who collect and handle solid wastes is protected. The handling of solid wastes involves processes such as collection, segregation and separation, containment, treatment, and disposal. Each type of waste has a different and unique way of being handled. Let’s now look at each type of waste and its appropriate handling technique.

Hazardous waste

Hazardous waste is handled through the use of the following 5 processes:

1. Waste determination

Hazardous waste must first be identified and separated from all other types of waste. This is a complex but important task.

2. Waste containment

After the hazardous waste has been identified, it must be collected in appropriate containers. The containers must be labelled and marked clearly. They must be kept closed when they are not in use. It is also extremely important that a waste log is maintained. The log should ideally contain information about how much hazardous waste is and the type of hazardous waste collected in containers. A container should never be over-packed with hazardous wastes.

3. Regular site inspection

The areas where hazardous waste is stored must be inspected at least once a week. Any type of leaks or spills should be recorded and fixed immediately. The containers in which waste is stored should be properly maintained.

4. Tracking of wastes

Hazardous waste must be tracked from its source to the site of the management and handling facility. This will ensure that vehicles transporting the wastes travel on well-maintained roads to minimize spillage. It can also later help in reversing public and environmental damage that may have occurred due to exposure to the wastes.

5. Preparation of plans and reports

A plan must be in place in case of an emergency such as a leak. All workers that manage hazardous waste should be properly and annually trained in procedures. It is also a good practice to maintain a report of the waste analyzed.

Bio-medical waste

Bio-medical waste is any waste that is generated from the diagnosis and treatment of human beings and animals. It also includes wastes produced from activities that involve biological research or tests. The handling of bio-medical wastes takes the form of the following steps:

1. Segregation

As with hazardous wastes, bio-medical wastes too must be carefully separated at the source itself. This allows the health risk of workers handling the waste to be reduced. Biomedical waste should also be segregated according to the type of treatment they need to undergo. Treatments include incineration, disinfection, chemical treatment, and disposal in a secured landfill.

2. Colour coding the containers used for disposal

Bio-medical wastes should be collected in containers that are colour-coded according to the hazard potential of the wastes. This helps in selecting the most appropriate disposal method.

3. Labeling of containers

Along with colour-coding, containers should also be labelled with the appropriate symbol. Symbols signify how dangerous the wastes are and the type of safety equipment that needs to be worn while handling it.

Radioactive waste

Radioactive wastes are wastes that contain radioactive material. It is a type of hazardous waste formed by nuclear activities like nuclear fission, nuclear power generation, and radiation treatment in hospitals.

All radioactive waste must first be separated according to its isotopic and physical state.

A particular area must be designated as the storage place for radioactive wastes. No other type of waste must be stored in the same area.

A radioactive hazard tag must be attached to each container containing the wastes.

The containers must remain closed at all times. They should be opened only when more waste is to be added.

Workers handling the wastes must be provided with proper shielding and safety equipment.

E-waste

E-waste is waste generated by the disposal, recycling, or resale of old electronic items like mobile phones, televisions, laptops, etc.

Firstly, electronic wastes should always be checked for labels that indicate how the item should be disposed of.

E-waste should only be handled by recycling agents that are authorized to do so.

Batteries should always be disposed of separately from the main product.

E-waste should never be disposed of in garbage bins along with municipal wastes.

Storage: Movable Bins, Fixed Bins

Wastes need to be stored in containers or bins before they can be collected. The size, type, and location of bins play an important role in the effective management of waste. The bins or containers can be of various sizes. Small sizes are mostly used in households and can be handled manually. On the other hand, large bins need to be handled by machines and are usually placed at locations that experience large crowds, such as railway and bus stations. Generally, storage bins fall into two categories:

1. Movable bins:

These are often used to transport wastes to the site of collection or transfer. The wastes in them are emptied into a collection vehicle or a bigger container for transfer to a disposal facility. After the waste has been emptied, the bins are returned back to the site of storage.

2. Fixed or stationary bins:

These bins cannot be moved. They are fixed in place. They are mainly used to collect wastes at the site of generation itself and are later picked up by collection vehicles.

Collection Services

A collection service is a waste management service offered that includes the gathering and hauling of wastes to collection vehicles. It usually has a high cost due to the cost of fuel and labour associated with it. The different types of collection services are:

1. Curb service:

This service is common in high-income countries. In this service, the house owner places the waste containers at the curb on a day scheduled for waste collection. The collection works empty these containers in a collection vehicle and place the container back on the curb.

2. Alley service:

Here, waste containers are placed in an alleyway. Workers empty these containers into the collection vehicle and place the containers back in the alley.

3. Set out-set back service:

In this service, collection workers visit each house. They collect the waste bins and empty them in vehicles. A new set of workers then collects the empty bins and returns them to the house.

Types of Collection Systems

There are two main collection systems that municipal bodies use. They are:

1. Primary collection:

In the primary collection systems, waste is collected at the same place of its generation. From here, it is picked by vehicles and transported to the site of disposal.

2. Secondary collection:

Here, waste is collected in communal bins. The wastes people generate are dropped off at large communal storage bins in public places. Collection vehicles later transport the wastes from these bins to a disposal facility.

3. Communal system:

This type of system is common in low-income countries. The communal system saves costs as it reduces the number of stops a collection vehicle would have to make. In this system, people bring their waste to a common point of collection or a common bin. The communal aspect of this system means that its effectiveness depends on the cooperation of the community. A major disadvantage, however, is that due to the collection point/bin being located in a public space, people tend to indiscriminately dispose of waste outside the bins.

4. Door-to-door system:

This system is more popular in industrialized and wealthier countries. In this method of collection, people place their waste bins at the back gates of their houses or in their vicinity. This is done on a specific day designated for collection. The collection workers visit each house and empty the waste into the collection vehicle. The empty bin is then set back on the property, and the workers move on to the next house. This system has a high cost associated with it since each property needs to be entered into by a worker.

Collection Routes

The proper planning of collection routes for vehicles is important in the effective management of waste. Collection routes must be optimized so that the time spent on loading, unloading, and driving can be reduced. The selection of collection routes depends on factors such as knowledge of local roads and their construction and design. The number of turns in a road, speed limits, and height restrictions also play an important factor in determining the routes for waste collection. The number of stops on a route must also be taken into account. In rural areas, there will be fewer stops for collection as compared to urban cities since, in rural areas, villages are far apart. A common waste industry ‘thumb rule’ is that there should be no more than 1,000 stops in an eight-hour collection shift.

GIS (Geographic Information System) has proven to be an effective means of planning and selecting optimized collection routes. GIS enables a user to spatially analyze the area and determine routes that would hinder the effective collection of wastes.

Route Optimization Strategies:

Below are some steps that can be followed to ensure an optimized waste collection route.

• Two collection routes should never overlap. Each route must be compacted and restricted to a specific geographical area.
• If waste is to be collected from heavily crowded streets, it should never be done during rush hours.
• If waste needs to be collected on a one-way street, it is best to start from the upstream end of the street.
• To conserve fuel, waste collection from high elevations should be placed at the start of the route.

The below diagram is an extremely simple model used to optimize waste collection routes.

Source: Researchgate.net

Also Read: Role of Various Organizations in Solid Waste Management