SOLID WASTE MANAGEMENT

By

Jean Faullimmel, Ph.D.

Background

On a recent environmental mission to the central region of the Visayas in the Philippines, via the German organization “Senior Experten Service” (SES), I had the opportunity to visit the islands of Cebu, Bohol, Negros Oriental and Siquijor. During the one-month exploratory mission, I witnessed the damaging effect of large open solid waste dumps on the environment and human health. The non-segregated biodegradable and non-biodegradable municipal solid waste was dumped there over the years, exposing surrounding communities and people working at the site to bad and toxic smells.

Source: Jean Faullimmel, Tagbilaran landfill, Bohol island, Philippines

The “open dump” approach is the primitive stage of landfill development and remains the predominant waste disposal option in most developing countries. It is the oldest form of waste treatment. A default strategy for municipal solid waste management, open dumps involve indiscriminate disposal of waste and limited measures to control operations.

As towns grow and produce more waste, and with insufficient and/or inefficient solid waste collection systems, the environmental impact from open dumps becomes increasingly intolerable. In many developing countries such dumps are still the primary method of waste disposal as it is the cheapest and the most convenient. Yet such type of waste disposal can degrade water, soil and air quality, and can thereby affect human health and causing ecological harm.

1

Leachates and landfill gases

Solid waste dumps create new types of waste or pollution. As garbage decomposes, moisture and rainwater produce a toxic liquid known as leachates. Water passes through the solid waste dump and extracts dissolved and suspended matter from it, and then slowly migrate down in the form of leachate to contaminate the groundwater.

Once the contaminant reaches the environment, it is acted on by chemical reactions and processes that tend to cause it to move within that medium or to move it to another medium. Chemicals may migrate from the site either by evaporation and then dispersed by winds, and in the form of leachates that can reach groundwater. Usually groundwater is the main source of drinking water for the population. If contaminated, less fresh water is available for the communities. Without remedial measures, open dump sites act as a continuing source of pollution as illustrated in the picture below:

Source: Council of Europe 2007

Landfills also generate gas that is composed of a mixture of hundreds of different gases. Aerobic and anaerobic bacterial decomposition, volatilization, and chemical reactions are responsible for the formation of landfill gas. The major and typical gas composition found in a mature landfill is the following:

2

Gases % (dry volume)-------------------------------------------------------------------------------------------Methane 45-60Carbon dioxide 40-60Nitrogen 2.0-5.0Oxygen 0.1-1.0Sulfides, disulfides, mercaptans 0.0-1.0Ammonia 0.1-1.0Hydrogen 0.0-0.2Carbon monoxide 0.0-0.2Trace constituents (volatile organic compounds) 0.01-0.06

Carbon dioxide and methane are the most potent greenhouse gases responsible for global warming and climate change.

Odors and health symptoms

People in communities living near or working at landfills are often concerned about odors. They wonder whether these odors are a source of undesirable health effects, such as headaches and nausea. At low-level concentrations, as in the case of landfills, it is unclear whether it is the chemical odors that trigger a response. However, the continued exposure to landfill odors may result in chronic diseases. They develop slowly over a long period of time. The symptoms of chronic poisoning occur at low level of contaminants and are usually not apparent over a long period of time. For example, workers in the asbestos and coal mines, or people who drink and smoke a lot, develop chronic illnesses, such a respiratory and cardio-vascular diseases, and different types of cancer. The same diseases can develop from landfill long-term gas exposure.

Source: Jean Faullimmel, Dumaguete landfill, Negros Oriental, Philippines

Potential landfill gases are sulfides, ammonia and volatile organic compounds (VOCs). These gases can migrate to surrounding communities. Among sulfides, hydrogen sulfide, dimethyl sulfide and mercaptans are the three most common sulfides responsible for

3

landfill odors. These gases produce a strong rotten-egg smell, even at very low concentrations. The human olfactory system is extremely sensitive to hydrogen sulfide and can smell such gas at a concentration as low as 5 part per billion (ppb).

Ammonia is another odorous landfill gas that is produced by the decomposition of organic matter. Ammonia is common in the environment and is an important chemical for maintaining plant and animal life. People are exposed daily to low levels of ammonia coming from the natural breakdown of manure and dead plants. Humans are much less sensitive to the odor of ammonia than they are to sulfide odors. The olfactory threshold for ammonia is between 28,000 and 50,000 ppb. Hydrocarbons or VOCs, may also cause odors, but they are usually emitted at very low concentration and may not pose severe odors problem and health effects.

Upgrading open landfills

An operated or semi-controlled dump is often the first stage in a country’s efforts to upgrade landfills. Controlled dumps operate with some form of inspection and recording of incoming wastes and practice extensive compaction of waste. Operated dumps, however, implement only limited measures to mitigate other environmental impacts. In developing countries, most operated dumps still practice unmanaged contaminant release and do not take into account environmental cautionary measures such as leachate and landfill gas management. This is especially relevant where leachate is produced and is unconstrained by permeable underlying rock or fissured geology. This issue may be less critical in semi-arid and arid climates, where dumps do not generate leachate in measurable quantities.

The conversion of open or operated dumps to engineered landfills or sanitary landfills is an essential step to avoid continuous air and water pollution and future costs from present mismanagement.

Sanitary landfill

Sanitary Landfills are solid waste dumping sites where waste is isolated from the environment to prevent air pollution and contamination of land and groundwater. The Figure below illustrates such type of landfill:

4

Source: “Environment” by S. Brennan and J. Withgott, 2004.

Basic conditions should be met before a site can be regarded as a sanitary landfill:

1. If a site cannot be isolated on land, additional lining materials should be brought to the site to reduce leakage of leachate from the base of the site and help reduce damage to the ecosystem.

2. If a liner - soil or synthetic - is provided without a system of leachate collection, all leachate will eventually reach the surrounding environment. Leachate collection and treatment must be stressed as a basic requirement.

3. A groundwater monitoring system is necessary to prevent contamination of drinking water.

4. A methane recovering well to use the gas as household fuel or to use it to generate electricity.

5. A permanent control waste management: training of staff should be based at the landfill to supervise the handling of incoming waste, that is, waste location, segregation of it, covering and the regular maintenance.

The goal of waste management

The goal of waste management is to dispose of solid waste safely and effectively and to reduce the amount of waste generated. Waste is a sign of inefficiency, so reducing or preventing it makes economic sense. Waste treatment has a cost, the less waste is

5

generated by industries and households, the less costs of disposal.

A successful solid waste management policy supports a resource-conserving hierarchy. The United States Environmental Protection Agency (EPA) has ranked the most environmentally sound strategies for municipal solid waste: (1) Source reduction is the most preferred method, followed by (2) reuse, (3) recycling, (4) composting, (5) incineration, and finally (6) landfills. It can be summarized in the figure below:

Source: European Commission, Environment

There are different approaches that industries and consumers can take to achieve source reduction or waste minimization.

Source reduction involves:

1. Improving manufacturing processes,2. Minimizing packaging,3. Purchasing “green product,”4. Composting household organic matters,5. Reuse items whenever possible.

Waste that needs to be managed:

1. Recovering items for recycling and reuse,2. Recovering material for composting,

Waste disposal involves:

1. Incineration of waste to energy,2. Waste disposal in landfill.

Classification of waste

For management purposes, solid waste is classified into different categories depending on their sources:

1) Household waste or municipal waste.2) Industrial waste as hazardous waste,

6

3) Biomedical waste or hospital waste as infectious waste.

Basically there is biodegradable and non-biodegradable solid waste. Biodegradable refers to any organic waste that is easily biodegraded by bacteria, either in aerobic or anaerobic conditions (with or without oxygen). The chemical industry deals also with hazardous waste that has even a more toxic effect on the environment and human health.

All this waste can be classified in four different broad categories: (1) Organic waste (kitchen waste, vegetables, flowers, leaves, fruits, etc.); (2) toxic waste (old medicines, paints, chemicals, bulbs, spray cans, fertilizer and pesticide containers, batteries, etc.); (3) recyclable or reuse waste (paper, glass, metals, plastics, electronics, etc.); and (4) hospital solid waste. Among all types of solid waste, packaging represents about 50% by volume.

Incineration waste to energy

When waste that cannot be recycled or reused, it can be safely incinerated, with landfill disposal only used as a last resort. Both these methods need close monitoring of air emission and possible groundwater contamination because of their potential for causing severe environmental damage.

Incineration reduces the stress on landfills, but they create other environmental side-effects. The ashes must be disposed of, either at a landfill, or if they are toxic, at a hazardous waste facility. The waste to energy process is illustrated below: Incinerating waste generates heat, which then transformed water into steam that will turn turbines to generate electricity.

Source: “Environment” by S. Brennan and J. Withgott, 2004

7

Burning waste also produces air contaminants that must be treated with expensive air pollution control equipment to avoid contributing to acid rain, ozone depletion and air pollution.

The construction of an incineration facility not only involves proper treatment of the resulting combustion gases, but also requires adequate air emission legislation. This concerns contaminants such as: VOCs, SO2, NOx (NO+NO2), HCl, HF, methane, dioxins, heavy metals and dust. In Europe the standard limits of these contaminants are very severe in order to mitigate their impact on the environment. If this legislation is not severe enough or incomplete, air pollution continues.

Resources recovery policy

Without a sound and reinforced waste recovery policy, reducing solid waste at the source will not work. Here the government and local authorities have a major role to play in implementing such policy. The policy must integrate appropriate resource-recovery practices in order to minimize the amount of solid waste that requires disposal, and that increases the use of reused and recycled materials.

The goal of the policy must be the following:

1. Incorporate solid waste reduction by resource recovery into waste management activities of industries, citizens and governments.

2. Integrate a waste management hierarchy as follows:

Reduce the amount of solid waste created, Reuse, recycle and compost, Recover landfill gases, Incinerate or dispose of in sanitary landfill.

3. Facilitate the use of recycled material and encourage the development of such markets.

4. Give technical and financial assistance for alternative waste treatment technologies, and promote legislation consistent with resource-recovery policy

.

European solid municipal waste treatment methods

The picture below illustrates the different municipal waste treatment methods used in Europe.

8

Source: Eurostat, 2009

The chart is divided into: recycling, composting, incineration, and landfill disposal. If we look at the two charts concerning the methods used in Poland and Germany, we realize that the former has the least inefficient solid waste management method, that is, most of the solid waste goes to landfills, with little recycling and no incineration. On the other hand, we have Germany, with the most efficient treatment methods, that is, recycling is the most important, followed by incineration, then composting and finally very little going to landfills. The latter meaning that what goes into the landfill, is ultimate waste, that cannot be recycled, reused, composted or incinerated. Efficient solid waste management also means reduction of greenhouse gases.

Conclusion

In the context that the Visayas region of the Philippines wants to promote tourism, sustainable solid waste management must be developed. First, existing local environmental legislation must be reviewed, changed or improved, and reinforced, in the context of the reality on the ground. An inventory and the development of an analytical database of the existing waste practices is necessary. It is important to know (1) how much waste is generated, (2) how it is handled, (3) where it is disposed of, and (4) its impact on the environment and human health. Without a clear idea of what exists, it is difficult to set objectives and targets on how to improved the situation. The current practices are not anymore acceptable as it leads to more water and air pollution. In the long run, pollution has a high cost: long term pollution leads to increasing human health and environmental damaging costs.

Based on the inventory and proper legislation, the questions to be asked is what type of waste management method should be adopted on the islands of Cebu, Bohol, Negros Oriental and Sequijor? It is clear that the open dump practices must be stopped. But replaced with what, sanitary landfills, incineration waste to energy or simply upgrading current waste disposal practices? Which one is feasible in the context of the legislation, investment budget, economics, and the opinion of the surrounding communities, in order to be able to promote a clean island?

9

If the final decision is between a sanitary landfill or incineration, the current waste handling method must first be improved by source reduction, reuse, recycling and composting practices. Waste segregation is very important in order to minimize the amount of waste that should be disposed of in landfill or incinerated. The better the segregation, the more waste can be reuse and recycled. In view that the islands have limited space, the growing cost of land, and a growing population generating more waste, the construction of sanitary landfills may not be the best solution.

Another issue to be considered is the rehabilitation of old landfills. What to do with the open dumps that continue to generate air and water pollution? The best way would be to use the waste to energy method to rehabilitate the land as quickly as possible. In this context, the German approach of prioritizing first reuse and recycling, then incineration and composting, and only landfill disposal as a last resource may seem to be most appropriate.

References:

1. Jean Faullimmel, Environmental mission to Cebu, Philippines, May 2011.2. Rene Burt Llanto, Head of Depart. of Science and Technology, Cebu.3. S. Brennan and J. Withgott, “Environment” Pearson, 2004.4. P.L. Bishop “Pollution Prevention” McGraw-Hill, 2000.5. Agency for toxic substances and disease Registry.6. US Environmental Protection Agency.

JF/20/07/2011

10