Transforming garbage for common good

Wednesday, 23 December 2015 00:02 -     - {{hitsCtrl.values.hits}}

 dfh

 

During the forum on the Western Region Megapolis Planning Project on 30 November, the Minister for Megapolis and Western Development Patali Champika Ranawaka stated: “We will call for proposals to solve Colombo city’s waste problem and intend to make the Western Province, generating almost half the island’s economic output, more liveable.” He continued that previous proposals to transport Colombo garbage to remote dumping sites or generate power by incinerating solid waste had been unsuccessful and Colombo now has three ‘garbage mountains’ with the biggest dump located at Bloemendhal Road.

 



Garbage problem6

Colombo is the biggest polluter in the country and the CMC’s collected refuse are dumped at different locations, while the former Bloemendahl garbage dump has been abandoned and shifted to Meethotamulla. In addition, Kesbewa Urban Council maintains a garbage mountain at Karadiyana near Boralesgomuwa. Practically every town has this problem as highlighted by protesting locals and reported over the media.

According to a survey conducted in 2005, cities collecting garbage exceeding 100 tons per day are Colombo (1,257 tonnes), Gampaha (313), Kandy (145), Batticaloa (119) and Galle (103 tonnes). Total collection of garbage per day in Sri Lanka is estimated to be 2,840 tonnes with 58% originating from the Western Province. Today, collection would be much higher.

The collection of garbage is only the basic problem; meanwhile, few local government councils have addressed the issue, with the Balangoda Urban Council in Ratnapura District leading the way, where garbage is recycled in an eco-friendly manner.

 



Garbage transport to Puttalam

The Mayor of Colombo has proposed to transfer 200 tonnes of garbage per day to Puttalam. Then, how about the balance garbage of over 1,000 tonnes per day? The garbage is to be transported by train from a transfer station at Meethotamulla to the proposed landfill at Aruakkalu, north of Puttalam. The Railway has completed the designs and the specifications for locomotives and rolling stocks for the transportation of garbage. The total cost of the project is expected to be $ 107 million (Rs. 14 billion).

Above is only the capital cost of the basic proposal; transport from the collecting towns to the loading point, from Aruakkalu station to dumping location and the running cost of the system would be substantial.

 



Disposal in Puttalam

The garbage transported to Puttalam is expected to be buried in voids created by the excavation of limestone for the cement factory and covered with soil. Establishing the garbage transport system would require three to four years. The dumping of garbage in Puttalam is opposed by environmentalists, who claim that the soil in the limestone voids located in the buffer zone of Wilpattu sanctuary would be degenerated by the leachate resulting from decomposing garbage. Meanwhile, this does not provide a solution to the garbage mountains building up at Meetotamulla, Grandpass and Karadiyana.

 



Landfill gas for power generation

Garbage when left alone decomposes and generates gases, typically containing around 45% methane among others, which could be burned. In some countries “wells” are drilled into garbage landfills and the gas is collected through a network of pipes. The gas is processed, combined with natural gas to fuel conventional combustion turbines or fuel small combustion or combined cycle turbines.

 



American experience

According to the Wall Street Journal, 12% of municipal solid waste in the US is burnt for energy. Supporters of waste-to-energy plants say such facilities reduce the need for land for dumps. But opponents claim that burning waste to produce energy is the least desirable way to deal with garbage. Such plants pollute the air, and their high capital costs divert resources from waste-reduction and recycling efforts. The average production of electricity from all US landfills is only 50 kilowatt-hours per ton of solids landfilled.

 

Sweden imports garbage

Swedes recycle almost half of their waste and use 52% to generate heat, with less than 1% of garbage being dumped. A network of 32 district heating plants burn garbage and transfer heat to 950,000 consumers’ homes through a network of underground pipes. Sweden imported 800,000 tonnes of well-sorted garbage in 2014, where all recyclable bits have been taken out.

 



Composting garbage

In simplest form, the process of composting involves heaping wetted organic matter such as leaves and food waste, and allowing the materials to break down into humus over a period. Worms, bacteria and fungi further break up the material. The decomposition process is aided by shredding the plant matter, adding water and ensuring proper aeration by regularly turning the mixture. Modern, methodical composting is a multi-step, closely monitored process with measured inputs of water, air, and carbon and nitrogen-rich materials. 

The world’s largest composting facility is in Edmonton, Canada which turns 220,000 tonnes of residential solid waste and 22,500 tonnes of bio solids (sewage sludge) per year into 80,000 tonnes of compost and occupies nearly 10 acres. The facility is heavily mechanised, mostly under cover and the compost is issued to farmers, landscapers, nurseries etc.

Another large facility in Lahore, Pakistan has a capacity to convert 1,000 tonnes of municipal solid waste per day into refuse-derived fuel (RDF) and the material is used as a fuel in the cement manufacture. Some claim that RDF could be used to generate power by burning.

 



Relevance to Sri Lanka

Consultants from western countries propose burning of garbage for power generation, as practiced in their countries. The garbage in developed countries consist only 20% vegetable matter and 80% paper and plastic, which are burnt at high temperature to generate heat and power. The garbage in Sri Lanka contains 70-80% vegetable matter and is considered unsuitable for power generation due to high moisture content.

Gases from garbage dumps can be collected, when garbage is dumped into large holes in the ground, trapping the gases which are then collected through a network of pipes over long periods of time. Our garbage is in mountains with the gases escaping into the air and collecting is not easy; also our people demand clearing of garbage mountains. Sweden’s handling of sorted garbage, though impressive, has no relevance to Sri Lanka as our homes do not require heating.

As shown above, the experiences in foreign countries is of no relevance to Sri Lanka; Canadian experience is useful, but their plant is highly mechanised and under cover due to cold conditions in their country. In Pakistan, compost is used as a fuel in cement manufacture, we could use produced compost to replace imported fertiliser.

 



Local experience in garbage conversion

Local garbage contains a high percentage (70-80%) of vegetable matter and is easily converted into compost. Of the local government units, the Solid Waste Management Unit run by the Balangoda Urban Council has been the torchbearer in the field, operating since 2003. They have been successful in the sale of their final product – compost as well as by-products. The council was awarded the National Productivity Award in 2005.

Their way of making compost fertiliser is the open window method.

 

  •  The graded waste is heaped into piles  
  •     On dry days, the pile is kept moist and the resulting bacteria action causes decomposition and the temperature rises
  •     The piles start distilling waste water (leachate) which is acidic and is guided to a separate tank
  •     The leachate is mixed with clean water and added back to the waste pile
  •     These piles are left alone for about six weeks
  •     Afterwards, the piles are turned over for airing
  •     Waste water is sprayed over the turned piles
  •     After a further two weeks the decayed waste is turned over and mixed
  •     After the second turning, the compost pile is left to dry to reduce moisture to 8%
  •     The decomposed product is graded by separating non-decayed materials from compost

The produced compost is enriched by mixing with paddy husk charcoal, obtained by controlled burning of paddy husk, a rich source of potassium.

 



Compost nutritional value

The NPK (Nitrogen, Phosphorous and Potassium) values for typical compost are around 0.5-0.5-0.5 which compares very poorly against the imported fertilisers currently used by the farmers. At the user level, compost contains adequate levels of the various mineral nutrients but can be low in trace elements.

NPK values are not the only consideration for plant nutrition, but involve processing of minerals and other nutrients by the soil organisms. The compost is the best, all around source of organic material as a nutrient for soil organisms. Most garden soils are low in organic content and the soil organisms in compost is an excellent source of these nutrients. Compost improves soil structure and drainage; organic materials cause slow-draining clayey soils to drain faster and fast-draining sandy soils to drain slower, thus reducing loss of soil moisture.

 



Disposal of compost

The Balangoda Urban Council has been lucky as they are able to dispose their products amongst the neighbouring farming community who were used to purchasing cow-dung. If all the garbage collected in Colombo region be converted into compost, the result would be a mountain of compost, the usage needs to be kept with quantum of composting. As such, revolutionary ways of usage of compost need to be found.

Organic farming commands premium prices and require compost. The Colombo and Gampaha Districts, where most garbage originates, possess large acreages under paddy fields, of which nearly 80% are uncultivated. Cultivation of idling lands with compost would consume large quantities of compost. Cultivation of indigenous varieties of rice, although low in yields, would command higher market prices. A better possibility lies in the cultivation of grass as cattle fodder for milk production.

 



Reduced subsidy in fertiliser

In towns outside the Western Province too garbage is a problem; in some locations such as Polonnaruwa the garbage dumps have attracted elephants. The current Budget proposes a cash subsidy instead of imported fertiliser for the farmers, which would create a heavy demand for compost, especially for paddy cultivation. In Colombo and Gampaha Districts, even the fertiliser subsidy failed to attract paddy cultivation.

 



Milk production

The country’s population consume large quantity of imported powdered milk. A litre packet of fresh milk sells around Rs. 200, while the milk farmer receives only Rs.65 per litre. If dairy farming is popularised, with the cattle fed on fodder cultivated in abandoned paddy lands, the populace in Western Province could be offered fresh milk at a lower price.

Until the 1970s the low-lying lands around Nawala and Pitakotte were grasslands that fed a large number of small dairy farms, who fulfilled the milk requirements of the city residents. With local governments discouraging cattle rearing, farms were forced to close down. Today, some small dairy farmers continue outside city limits, without grasslands of their own. Dairy farming could be popularized outside city centres; however, moving forward would require a well coordinated program.

 



Program

Large percentages of paddy fields in the Colombo and Gampaha Districts remain uncultivated, although the country’s legislation allows takeover of such lands. The landowners need to be encouraged to re-cultivate their idling paddy lands, with indigenous varieties of rice, vegetables or grasslands as fodder, all using compost supplied at a nominal price.

Consumers avoid milk from small farmers due to hygienic concerns; farms with few milking cows, living on muddy floors, milked by hand and using unclean containers comes to mind. For fresh milk to be acceptable to the consumer, farm quality should be improved by converting to mechanised milking. According to the Internet, mechanised milking machine prices start from $ 400 or Rs. 60,000 duty free, and small farmers would require financial assistance.



The proposed dairies would be;

1. Current large milk producers starting pilot units in each district

2. Farmers who already have a few cattle

3. Current land owners wishing to commence dairying

4. New ventures

Large dairies need grasslands on their own, for food security of their cattle. The small farmers could supply grass to large dairies on a contract basis, using small machinery for land preparation and harvesting.

 



Large milk producers

The Government could acquire uncultivated paddy fields in Kesbewa, Homagama, Kaduwela, Gampaha and Ja-ela electorates and offer them to large companies already engaged in milk related business to commence large dairies. They could purchase lands from high-grounds for cattle sheds and for milk processing centres; also import their cattle requirements.

 



Small farmers

The Government could offer farmers possessing a few head of cattle, paddy lands for grass  cultivation and high land for a cattle shed and a residence. They could be financially supported for purchase of equipment, and helped under Samurdhi scheme to put up a house.

 



New ventures

Companies wishing to venture into cattle farming could be helped by offering paddy lands based on capital raised. They too could buy own lands for factories.

 



Land owners wishing to start farms 

Paddy land owners wishing to commence cattle farming could learn farming in Government farms and given cattle at subsidised prices, based on the extent of paddy lands. Successful farmers could receive priority in getting adjacent lands for expansion.

 



The way forward

The proposal for Megapolis for the Western Province would convert the region to an industrial and financial base, multi-storied housing accommodating slum dwellers and the influx of middle class employees. Low lying regions would be excavated for flood retention and excavated material used for raising grounds for recreation purposes. These developments would confine around newly improved cities. But away from the development centres lay large extents of abandoned paddy fields which require utilization in an economically viable manner.

When the Government accepts the policy of converting garbage to compost and offer subsidised compost to cultivators, incentives for cattle rearing, reduced duty on related machinery and equipment, along with the possibility of paddy lands being taken over, land owners would be sure to respond positively.

Karadiyana garbage dump currently producing compost could meet the immediate demand and farmers can be issued with compost. The produced compost could be offered on nominal terms covering only packing and transport costs.

Lands uncultivated for long periods can be acquired and the existing small cattle owners be helped first by allocating lands for fodder cultivation, which would be an eye opener for others. Progress of small time investors would depend on the supply of cattle, while larger organisations require only Government policy and tax incentives.

Proper implementation of proposals would convert garbage from a liability into an asset. Utilisation of abandoned paddy fields would create employment, supplying organic rice and vegetables, greens and lower cost fresh milk, ensuring Western Province becoming self-sufficient in milk. Providing subsidised compost would be cheaper than building infrastructure and transporting garbage to burying locations. The cost of transport of garbage would be a waste, whereas encouraging cattle rearing would create self-sustaining farmers and a healthy nation.

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