Solid waste disposal : Sanitary landfill the best option
By Prof. O. A. Ileperuma-May 24, 2016, 8:00 pm
The Colombo city generates around 1200 tons of garbage daily requiring disposal by the municipal council. The standard practice adopted for disposing solid waste is the open dumping method, where garbage is dumped in low-lying marshlands such as those in Orugodawatte, Wanathamulla and Kolonnawa. Earlier Wanthamulla was a favourite dumping ground, but now it is the site of a housing complex built on the reclaimed land from the earlier dumping site. There is tremendous pressure against disposing garbage in their localities from the people living close to these open dumping sites at Orugodawatte and Kolonnawa. Rapid urbanisation, population growth and increase in non-biodegradable waste, comprising plastics and polythenes, are responsible for this trend. People living close to Kolonnawa garbage have already sought relief from the Supreme Court to prohibit the Colombo Municipal Council (CMC) from dumping garbage in their area.
Open dumping of garbage is not at all satisfactory for dumping municipality garbage for the following reasons.
Polythene content of garbage is increasing and the area required for dumping also increases
Promotes breeding grounds for mosquitoes, rats, flies and various other microorganisms
Aesthetically repelling mountains of garbage with unbearable smell has indirect effects on the social behaviour of people. People become agitated and irritable and may even develop violent behaviour.
During the dry season, fires created accidentally or deliberately produce massive fires which are difficult to distinguish. Since the fires spread through the mountain of garbage, extinguishing the fire at one point does not solve the problem.
Since there is no separation of garbage, toxic elements such as cadmium which leach out from batteries end up in their leachate contaminating water bodies. The leachate is also rich in various pathogenic bacteria and viruses causing illnesses to people.
During the hot summer months when there are fires in the open dumps, a lot of people, particularly children, get sick and admitted to hospitals for treatment. Major air pollutants generated during these fires are: fine particles (PM10), sulphur dioxide, nitrogen dioxide and carbon monoxide. Out of these fine particles are perhaps the most toxic pollutants producing various respiratory problems such as asthma, bronchitis, pneumonia and long term health problems like lung cancer and emphysema. In addition, these dumps provide ideal breeding grounds for mosquitoes resulting in dengue fever, typhoid and various other vector borne diseases.
Blocking of low lying marshland is detrimental to the proper control of rainwater discharge. Low lying wetlands also provide scenic areas for recreation and provide sanctuary to various migratory birds. They also serve to preserve the rich biodiversity with mangroves, fish and birds characteristic of these areas.
Sanitary landfills- A healthier option?
Most developed countries dispose their solid waste in sanitary landfills. These are usually waste lands such as abandoned mines, rock quarries and located away from populated areas and ecologically important sites. They have an impervious clay layer to reduce water seepage. The area varies, but at least of the size of 3-4 soccer grounds. The bottom is dug up, flattened and sometimes lined with heavy duty polythene and a thick rubber mat to prevent seepage of the leachate. Garbage brought by trucks is dumped and compressed after placing a thin layer of soil using a bulldozer. The advantages are that there is no smell and does not breed any pathogens. It is called a sanitary landfill because of its sanitary condition compared to an open landfill. The leachate which is the liquid flowing out of a sanitary landfill is subjected to disinfection to kill all bacteria and viruses and monitored for other water quality parameters such as heavy metals, suspended solids etc. before it is discharged to waterways.
Nearly 20 years ago, the Government saw the need to tackle the ever increasing solid waste in the Colombo city. Government sought the support of the World Bank, which undertook a feasibility study for constructing a sanitary landfill for the entire Western Province. They identified a land at Alupotha close to Hanwella, located between two hillocks and having a clayey soil with no ecologically sensitive areas in the near vicinity and sparsely populated. The proposal was to dispose garbage generated from all municipalities from Negombo down to Panadaura including Colombo city. World Bank was willing to provide full funding for this proposal. Unfortunately, this programme never got off the ground due to lack of a commitment from a strong political leadership. Environmental NGO’s are quick to capitalize on issues of this nature to organise protests and incite villagers into protests to satisfy their own self interests. They can show what they have done to their foreign masters and get more funding. In the above case, these NGO’s not only got a few villagers , mostly illegal squatters in these lands, to protest but also local politicians to protest with the slogan "We do not want Colombo garbage". In this instance tenders were called and there were a lot of discussions held for eight long years from 1991-1999 but the project was cancelled for unknown reasons.
Politicians in Sri Lanka act only in the interest of safeguarding their vote bank and not on the national needs. They simply do not have the courage nor the leadership to take decisions which will benefit the majority. They are surrounded by their cronies as advisors, who will act as stonewalls between the President or the minister concerned and independent professionals, to prevent the implementation of any worthwhile proposals of national significance. This was the reason why this excellent proposal was doomed. The World Bank merely folded up their funds and probably funded a similar project in some other country.
The silver lining on this problem is the construction of a small scale sanitary landfill at Kirindiwela to dispose garbage from the Dompe Pradeshiya Sabha. This was built with support from the Korean Government at a cost of US$ 6 million and able to accept around 90 tons of garbage per day. The expected lifetime of the landfill is around 25 years, but could last longer since this Pradeshiya Sabha produces only around 10-15 tons of garbage a day. The leachate from the this landfill is collected in a storage tank where it is treated before disposal to the environment. This is a positive step, but a much larger sanitary landfill is required for disposing garbage from the entire Western Province. Those who are opposed to disposing garbage at landfills should visit this landfill and convince themselves of the ideal option to dispose municipality garbage.
Colombo garbage to Puttalam?
Now there is a proposal to dump garbage from Colombo in abandoned limestone quarries at Aruwakkalu located north of Puttalam. It is here that limestone is quarried for the manufacture of cement at the Holcim cement factory at Puttalam. While there are some objections based on biodiversity and archaeological importance, the major reason against this option is the high cost involved in transporting garbage over a distance of around 150 km by train. Alupotha, on the other hand, is located in close proximity to the Kelani valley railway line and located only about 40 km by train. Garbage can be transported in open freight cars from Kolonanawa to Alupotha in a more economical manner. Again, this entails collection of garbage from the entire western province and eases problems local government bodies face in finding suitable locations to dispose their garbage, and avoids conflicts with people who are angry about dumping garbage in their own backyards. Our megapolis minister should seriously consider this option of a centralised solution in the form of a sanitary landfill to solve the problem of garbage disposal in the entire Western Province.
Garbage as a resource
Arthur C Clarke once said "Garbage is only raw material which people are stupid not to use". Most developed countries have a scientific approach to managing their solid waste. Producing energy from waste is an attractive option. There are two basic approaches: incineration and bio-gas generation. In countries like Japan, non-biodegradable and burnable waste are sorted out and incinerated. The resultant energy can be used to turn turbines and produce electricity. In tropical countries like ours, garbage is more than 75% organic and also it is too wet to burn directly. This leads to some problems in incineration. However, such wastes can be conveniently used in bio-gas generation. The resulting bio-gas can be used in power plants to produce electricity. In addition, electronic waste dumped in landfills represent wastage of several important metals such as cadmium, gold, silver, mercury and lead going down the drain. With appropriate technology, these can be recovered and there are established methods to extract such metals. Otherwise, these toxic metals may find their way into waterways and cause heavy metal pollution detrimental to our health. Similarly, plastics can be recycled to produce other products such as water pots, garden furniture and plastic containers. Water bottles we throw away after use can be directly recycled to produce new pet bottles. Other metals such as iron, aluminium and tin too can be recycled.
Conclusion
We should have an entirely new way of thinking on the disposal of garbage. It should not be considered as a nuisance, but a resource by itself. Many people can find gainful employment in a new industry which uses electronic wastes to extract expensive metals like gold and other metals. There is definitely a lot of science involved here to make this a profitable venture. The development of the Western Province as a megapolis will definitely benefit from a modern system to dispose its garbage, and this will help to attract investors. There is also a need for disposing special kinds of wastes such as toxic chemicals and separate specialised sanitary landfills should be constructed to dispose such types of garbage.
