An Urban Waste Management Continuum


Hari Srinivas
Emerging Trends Series E-040. June 2015


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rising quality of life, and high rates of resource consumption patterns have had a unintended and negative impact on the urban environment - generation of wastes far beyond the handling capacities of urban governments and agencies. Cities are now grappling with the problems of high volumes of waste, the costs involved, the disposal technologies and methodologies, and the impact of wastes on the local and global environment.

Most local governments and urban agencies have, time and again, identified waste management as a major problem that has reached proportions requiring drastic measures. We can observe three key trends with respect to solid waste - increase in shear volume of waste generated by urban residents; change in the quality or make-up of waste generated; and the disposal method of waste collected, by land-fill, incineration etc.

But these problems have also provided a window of opportunity for cities to find solutions - involving the community and the private sector; involving innovative technologies and disposal methods; and involving behaviour changes and awareness raising. These issues have been amply demonstrated by good practices from many cities around the world. There is a need, therefore, for a complete rethinking of "waste" - to analyse if waste is indeed a 'waste'.

The current emphasis on waste disposal that is focused on municipalities and uses high energy/high technology, needs to move more towards waste processing and waste recycling that involves public-private partnerships, aiming at eventually waste minimization, driven at the community level, and using low energy/low technology resources. Some of the defining criteria for future waste minimization programmes will include deeper community participation, understanding economic benefits/recovery of waste, focusing on product life cycles (rather than end-of-pipe solutions), decentralized administration of waste, minimizing environmental impacts, and reconciling investment costs with long-term goals.

The above four key aspects of waste management disposal, processing, recycling and minimization is presented here in the form of a dual-axis continuum (see Figure 1), which will help in understanding the actions to be taken, and in building a comprehensive waste management strategy for local governments in cities of developing countries.


Waste Processing
Waste Minimization
Waste Disposal
Waste Recycling

Waste Disposal

Historically, efforts in the management of waste have focused primarily on the disposal part of the waste. Whilst there is now a general move towards the recovery of resources from waste, disposal is still the most common form of managing waste. Dumping, landfilling of waste and incineration are some of the most common methods of waste disposal.


Waste Processing
Waste Minimization
Waste Disposal
Waste Recycling

Waste
Recycling

Recycling is the breaking down of materials from waste streams into raw materials, which are then reprocessed either into the same material (closed loop) or a new product (open loop), generally including waste separation and material reprocessing. There are various materials that are capable of being recycled, and technology is advancing to allow the recycling of more materials.

The benefits of recycling do not lie solely in diversion of waste away from disposal but, even more importantly, in the reduction of the amount of virgin resources that need to be harvested and processed for the manufacture of new products.


Waste Processing
Waste Minimization
Waste Disposal
Waste Recycling

Waste
Processing

Waste processing is the range of activities characterized by the treatment and recovery (use) of materials or energy from waste through thermal, chemical, or biological means. It also covers hazardous waste handling. Generally, there are two main groups of processes to be considered, (1) Biological processes, such as open composting, enclosed composting, anaerobic digestion, and vermiculture, and (2) Thermal processes, such as incineration, and gasification.

Examples of reuse in initiatives include: (1) Product reuse - rethreading tires, recovery of demolition materials, reuse of plastic bags, second hand clothing, reconditioning and repair of furniture and appliances; (2) Materials reuse Liquid-paper board for seedlings planters, bottles, scrap paper for notes/phone messages, mulching; (3) Durable packaging - e.g. milk crates, bread trays, string or calico shopping bags.

Some of the positive effects associated with processed waste include, more effective use of resources, employment opportunities in the service and repair industries, support for charity based stores, better protection of products as durable packaging is more robust, and changes in attitudes towards disposable products.


Waste Processing
Waste Minimization
Waste Disposal
Waste Recycling

Waste
Minimization

Waste minimization is aimed at reducing the production of waste through education and improved production process rather than aiming to increase technology to improve treatment of waste. The idea of minimization is not centered on technological advances, it can be viewed a method of managing existing resources and technology in order to maximise the efficiency of available resource use. Minimizing waste generation has the potential to reduce costs or increase profits by maximizing the use of resources and by reducing the amount of waste to be disposed of the cost of waste management is also decreased.

Waste avoidance for individuals: Buying goods in bulk; reconsidering superfluous purchases; purchasing products in materials/packaging that is readily recycled; use of alternatives, e.g. landscaping that creates mulched gardens in place of lawns; and use of composting and vermiculture practices.

Waste minimization in industry: Change in product design to reduce materials consumption; using crates instead of pallets to avoid the need for shrink wrap; incorporate Eco-Design technology into production processes; adoption of Cleaner Production practices that ensure avoidance through efficiency measures; and conduct regular audits and monitoring of waste reduction/resource recovery practices.

Waste minimization for Local Government: Encourage community 'avoidance' activities, e.g. promote competitions rewarding initiative in this area of resource recovery; lead by example, e.g. display mulched gardens throughout the municipality; and provide facilities and infrastructure to assist industry, business and the community to undertake resource recovery practices, e.g. kerbside recycling and resource exchange registers, initiate greener procurement programmes.


These four issues, disposal, recycling, processing, and minimization, have been put into a dual axis continuum illustrated in Figure 1.

The Waste Management Continuum

The Waste Management Continuum has two axes. One is the horizontal stakeholder scale, ranging from municipalities and local governments to the community. The other is the vertical technology scale ranging from high tech/high energy disposal systems to low tech low energy systems.

Much of current waste management efforts is focused on local government based high tech/high energy disposal systems (the 'NOW" position in the continuum). We need to move towards a waste management system that is community based using low tech/low energy, and focused on waste minimization. In achieving this goal, we also have to pass through the 'gray' areas of waste processing and waste recycling too.

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Contact: Hari Srinivas - hsrinivas@gdrc.org