Sustainable waste management

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Recently, Kathmandu Metropolitan City (KMC) issued a public notice asking people to separate biodegradable and non-degradable waste before handing it over to collectors. Several people support this idea and believe that it will miraculously solve the waste management situation in Kathmandu. There is an ongoing discussion about producing compost from biodegradable waste, recycling what can be reused, and incinerating the rest. All of these ideas seem suitable for waste management, but the million dollar question is whether these waste management ideas are feasible and practical for Kathmandu.

Waste separation means we need more containers to store different types of waste and more trips to landfills to dispose of it, which increases management costs. Control of sorted household waste is complex and not always pure, so biodegradable waste always requires separation of impurities, which can be costly. Composting is a slow process and requires a lot of space and time. Many composting plants in Kathmandu have failed for lack of a compost market. Similarly, waste incineration is expensive and consumes a significant amount of energy. The heat from the incineration plants can be sold to large industries such as cement works, but it is necessary to lay a good network of pipes which is expensive and unwieldy.

In addition to sorting waste at home, KMC should consider alternative waste management procedures suitable for Kathmandu. Waste management experts have proposed a simple and well-known principle for sustainable waste management, namely reduce, recover and recycle. These principles will help to solve the problem of waste management in Kathmandu to a large extent.

Waste reduction

First, we need to understand the waste stream scenario to reduce waste generation. Most of the food waste generated by KMC comes from raw or unprocessed food transported from outside the Kathmandu Valley. Encouraging the transport of ready-to-cook or ready-to-eat foods (e.g. peeled and chopped potatoes), vegetables, meat and other produce will prevent a significant amount of food waste from entering the city . For example, 15% of a potato is turned into waste after being peeled and prepared for cooking. Kathmandu consumes around 92,000 tons of potatoes annually, producing 14,000 tons of potato skins in the process.

Similarly, Kathmandu consumes 34,000 tons of meat products per year, which means that 20,000 tons of animal waste are produced annually. This can be reduced by bringing in processed meat instead of live animals from outside. Many other products come with possible waste, which can be reduced by bringing in the processed product. Transporting ready-to-cook meat instead of live animals reduces the waste load and makes the product cheaper. The promotion of organic waste consumption at home through rooftop farming should be further encouraged. It is also essential to support window farming in Kathmandu as a significant number of people live in rented rooms or apartments that do not have access to the roof.

Recovery and recycling

Nepal imports 985 tons of charcoal per year, spending 1 billion rupees in 2020. But recycling our organic waste could help us replace charcoal with briquettes. There are several ways to produce briquettes from municipal solid waste, but one simple method is to mechanically dehydrate the organic waste mixed with a binder and press it into a mold and dry it. This briquette can be used as energy by different industries such as brickyards and cement factories. In this model, only a few companies can consume the entire production of briquettes. KMC produces approximately 73,000 tons of municipal waste per year or 40,000 tons of organic waste. Organic waste contains approximately 90% moisture, which must be screw-pressed to dehydrate it and reduce 80% of its weight and 50% of its volume. Based on this calculation, 8,000 tonnes of briquettes can be produced annually from Kathmandu’s organic waste, offsetting the charcoal needed in Nepal and reducing imports.

Kathmandu produces 550 tons of plastic waste per year. Briquettes of plastic waste have already been tested in Nepal on a small scale. The plastic briquette is a great solution for eliminating non-recyclable plastic, but cleaning up harmful combustion gases can be expensive. Additionally, it requires multiple processes and thermal energy which can be expensive. Changing the policy to produce recyclable plastic and recycle it into new plastic would be a better solution. However, if the furnace or boiler can accommodate the combustion of raw plastic materials, this could be advantageous as plastic has a high calorific value: 10,000 Kcal/kg.

Significant debris pollution is caused by the empty plastic bottles commonly found along the riverbanks. About 400,000 plastic bottles are thrown away every day in Kathmandu. Pollution from plastic bottles can be controlled by making the companies that use them, such as mineral water and beverage companies, responsible for the management of empty plastic bottles. Maybe they can pay for the empty bottles (eg 5 rupees each) so that the consumer collects them and sells them instead of throwing them in the street. The production of valuable/salable bottles by any company using plastic bottles is a common practice to reduce plastic bottle pollution in many developed countries, including Finland.

It is well known that there are many possibilities for the recovery of different waste streams, but only a tiny part of these is recycled and a large part is landfilled without recovering its value. Many factors must work together to turn to waste processing, and one of the most critical factors is to develop the concept of the waste recycling business. A quick example of a functional waste management business is waste collection from households, as it is simple and profitable for the entrepreneur. Waste contractors receive a fee from households, so they collect their waste and send it to landfill. Dealing with a larger amount of accumulated waste is complicated, expensive and requires considerable effort from the local government. Public-private partnership is a very successful model for municipal waste management. For this model, the local government needs an excellent policy such as economic support, subsidies, low interest loans, investment guarantees and market guarantees for their products (biogas, electricity, compost , animal feed, protein) to attract entrepreneurs. And, of course, it is necessary to work closely with other stakeholders.

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