Waste is Energy
When life gives you rubbish, use it wisely.
People in low-income countries, including those in Asia, have been conditioned to accept the presence of waste dumped in their surroundings, whether it’s on open land or in the streets. As long as it is not literally in one’s own backyard, waste dumps are tolerated. Many people, decision makers included, are not aware of the harmful impacts to human health, to groundwater resources and to the environment in general. Moreover, few realise that waste is energy – a product that can generate electricity and income.
The World Bank estimates that about 2.01 billion tonnes of solid waste is being generated worldwide annually, with at least one-third of that not managed in an environmentally safe manner. By 2050, global waste is expected to grow to 3.4 billion tonnes, more than double the rate of population growth. In lowand middle-income countries, food and green waste comprise more than half of the waste generated, while in high-income countries, the proportion of organic waste is about one-third due to the larger amounts of packaging and other nonorganic waste.
What is Waste-to-Energy?
Anaerobic digestion is a biological process that produces a gas principally composed of methane (CH₄) and carbon dioxide (CO₂), otherwise known as biogas. These gases are produced from organic wastes such as livestock manure, green waste, food processing waste, and so on. Biogas feeds an enginegenerator (i.e., a combustion engine), where the resulting mechanWical energy powers an electric generator to produce electricity. Most anaerobic digestion technologies are commercially available, and those that generate electricity are also widely available;
“As long as it is not literally in one’s own backyard, waste dumps are tolerated. Many people, decision makers included, are not aware of the harmful impacts to human health,to groundwater resources and to the environment in general”
it is no longer an “experimental technology”. There are millions of small, medium and large (> 0.5 megawatt) biogas power plants around the world, including Asia.
Using biomass to produce electricity reduces our reliance on fossil fuels, the primary energy sources for electricity and the largest contributors to the air pollution and greenhouse gases responsible for unpredictable changes in our climate. We will eventually run out of fossil fuels, so we have no choice but to find alternatives, sooner or later.
Biomass electricity offers an alternative with many benefits:
∙ Our supply of biomass is renewable, meaning it will not run out, provided that we have organic waste materials being produced and available.
∙ The electricity produced by biomass reduces the threat of further global warming.
∙ Making use of biomass waste eliminates the need to place it in landfills.
∙ Using by-product methane gases to produce electricity eliminates the associated odour and reduces air pollution in surrounding areas.
Waste-to-Energy (WtE) can be realised via the following principal technological systems: landfill gas capture, incineration, refuse-derived fuel production, and biogas production from anaerobic digestion.
Waste in Asia and its value
According to the World Bank, the East Asia and Pacific region generates the most waste globally, an average of 0.56 kilograms per person per day. Just over half of the region’s waste is composed of food and green waste, while dry recyclables comprise about one-third of the waste. On average, roughly half goes into landfill, around a quarter is incinerated, and less than 10 percent is recycled.
In many low-income countries, the waste produced contributes to the emission of greenhouse gases (GHGs), which in turn contributes to global warming. In these countries, waste management has not been able to reach a certain level of maturity due to the lack of, or poor development of, logistics systems, processing, leadership and management capacity, and awareness and education in general.
In South Asia, about 57 percent of waste can be characterised as organic. Open dumping is common practice, with a staggering threequarters of waste dumped in the open and only a few percent going into landfills. While WtE incineration potential has gained interest, substantial results have not yet been proven.
In Singapore, about 7.70 million tonnes of solid waste was generated in 2017 (down from 7.81 million tonnes the previous year), and approximately 61 percent was recycled. Solid waste that cannot be recycled is incinerated in four WTE power plants, the largest of which – the 1,600-megawatt-hour Tuas South Incineration Plant – produces enough electricity to power 125,000 four-room HDB flats. Singapore’s policy is geared towards the principles of sustainable development, as the country has no space to waste and no nature to destroy. Its RRR (Reduce-Reuse-Recycle) programme has become well known among its citizens and serves as an inspiration to leaders of Asian and African countries.
Moving forward
Land-scarce Singapore can’t afford to rest on its laurels: With the current rates of solid waste and incineration ash generation, its current landfill capacity could be exhausted within 15 years. Three mega-projects are in the works – the Deep Tunnel Sewerage System (DTSS), the Integrated Waste Management Facility (IWMF), and the Tuas Water Reclamation Plant (TWRP) – and the island nation is hoping that they will provide the definitive
“Solid waste that cannot be recycled is incinerated in four WTE power plants, the largest of which – the 1,600-megawatthour Tuas South Incineration Plant – produces enough electricity to power 125,000 four-room HDB flats”
answer to the mounting problem of waste.
While the trifecta of projects isn’t expected to be completed until 2027, a great deal of progress has already been made. At a cost of some S$3 billion, the IWMF solid-waste
management facility will incinerate trash and sludge (a by-product of used water treatment), treat food waste, and sort recyclables – all at one site.
Sludge from sewage treatment has long been processed using machines called digesters, which break down the organic matter into biogas. But Singapore has also begun turning food waste into fuel in a similar way, with the recently completed Ulu Pandan Water Reclamation Plant now processing a few tonnes of food waste daily. With the technology that will be installed in the Tuas plant, tests are being conducted to increase energy production by mixing combining sludge with the fats, carbohydrates and proteins that are in the food waste. As well as a biogas energy capability, the facility will have a large incineration capacity, enough to run its operations and ensure long-term sustainability.
Countries such as China, India, the Philippines and Thailand are embarking on WtE projects. Hong Kong authorities have awarded Singaporean WtE company Keppel Seghers and its Chinese partner, Zhen
Hu, a contract worth US$4 billion for the territory’s first integrated waste management facility. China is also preparing for a large increase in WtE projects, aiming to convert 30 percent of its municipal waste into energy by 2030.
With the right policies, public participation, incentive schemes, and political and professional leadership, countries can acquire the right “clean” technologies to convert organic waste into electricity. Stakeholders and investors need to understand that waste has a profitable future – and that managing it sustainably serves the interest of all living beings.
Atem S Ramsundersingh is the CEO and Member of the Board of Directors of WEnergy Global Pte. Ltd., Singapore. He was formerly a senior professional with the World Bank in Washington, DC (USA) and Program Director with the UNESCO-IHE Institute for Water in Delft (Netherlands).