GREEN ENERGY FROM WASTE
A STAGGERING 30,000 tonnes is the amount of waste Malaysians produce daily on average – this figure was disclosed at the National Waste Management Conference 2018 in July.
Worse, only 5% of the 30,000 tonnes are recycled.
That means the remaining 95% of waste or 10.4mil tonnes a year make its way to landfills across the country.
Selangor alone contributes 7,000 tonnes daily to these saturated disposal areas that are quickly piling up as sources of land and air pollution.
Enter the proposal for a Waste-To-Energy (WTE) treatment system by Worldwide Holdings Berhad, a subsidiary of the Selangor government.
For this RM500mil WTE project, Worldwide Holdings is partnering with Western Power Clean Energy Sdn Bhd, a subsidiary of China Western Power Industrial Co.
A joint development agreement was signed on Dec 10 for a WTE facility to be built adjacent to the Jeram sanitary landfill in Kapar, Selangor.
Operational by 2022
“The Waste-To-Energy concept is a waste management technology that is able to convert solid waste into energy in the form of electrical power,” explained Worldwide Group chief executive officer Datin Paduka Norazlina Zakaria.
There are two phases to the project with an estimated cost of RM1bil in total. The first phase with Western Power Clean Energy is expected to be operational by 2022.
“The first phase will have waste capacity of 1,000 tonnes per day, which will produce between 20MW to 25MW of green energy enough to power 25,000 households within the vicinity of the plant,” she said.
According to Worldwide Holdings chief operating officer (environment) Zamri Abdul Rahman, the amount of waste in Selangor increases at a higher yearly rate of 4-5%, compared to 2.5% national increase. He pegs this on urbanisation and population hikes.
“About 20ha of land is used up as landfill in a year,” he said, adding Worldwide Holdings embarked on plans for the development to save land consumption in Selangor.
Feasibility studies comparing landfills and WTE were done, with results showing that WTEs have a longer lifespan than landfills.
“95% of WTE in the world uses the type of technology we are planning to use which complies with EU standards of regulation,” said Zamri.
However, Worldwide Holdings has yet to decide if it will continue with the second phase, set to be completed by 2024, with Western Power Clean Energy.
How it works
Four major components form the WTE’s functions.
It works as an indoor storage facility for solid waste, enclosed incinerator, steam-powered energy generator and a gas filtration system.
Dealing specifically with municipal solid waste or domestic rubbish, the waste will be deposited in a lined bunker.
As domestic waste is high in moisture content, it will be stored for three to seven days and rotated repeatedly to ensure it is evenly scattered as microorganisms facilitate the fermentation of organic waste so it can be burned easily.
Leachate from moisture produced by the stored waste will then be filtered out to the Jeram sanitary landfill’s leachate treatment plant.
Waste will then be carried to the negative pressure incinerator using a bucket crane, said Zamri.
“Negative pressure means instead of air going out, air from the bunker where we store waste will be pumped into the burner and used for combustion to reduce the discharge of bad odours,” he added, stressing that no air will be released from the incinerator during the combustion process.
The burner reaches high temperatures of more than 850°C to incinerate the waste entirely.
Meanwhile water is heated using the high temperatures of the incinerator to produce steam, which is then transferred to steam turbines that generate thermal energy.
Ashes to ashes
“Two types of ashes form during the burning process. The first is bottom ash which is non-toxic ash usually created by wood and such materials. The harmless bottom ash will be sent to the landfill. Some countries use bottom ash for road construction or making low quality bricks, a possibility we will look into.
“The harder part to treat is fly ash. It contains hazardous materials and particles such as sulphur dioxide and nitrogen oxide. We’ll use activated carbon and slake lime to neutralise these acidic components,” said Zamri.
The process also involves a scrubbing system and burning at the highest temperature so that all toxins and pollutants are destroyed.
“Like other parts of the world, we will neutralise the fly ash then encapsulate it in cement and carry out leaching tests before it is deposited in the landfill,” he said.
Perhaps the most important step is how gas from the combustion unit is treated.
“There is also the matter of the toxic fumes dioxin and furan, normally associated with the burning of plastic.
“These will also be taken care of using an activated carbon injection system into the gas before it enters a bag filter, which captures the dioxin, furan and mercury,” he said.
Zamri said Worldwide Holdings will secure skills-based training through their partnership with Western Power Clean Energy.
Essentially the transfer of technology and knowledge will provide Worldwide Holdings with the tools to carry out their duties consistently.
Worldwide Holdings has also assured the state government and Department of Environment (DoE) that it will have an online display for the public to monitor emission levels in real-time and ensure that the operator meets the standards set.
The bic picture
The WTE project is part of a broader and more complete approach, namely Worldwide Holdings’ Integrated Solid Waste Management Centre in Jeram.
The centre is touted as a multi-faceted approach that includes everything from an anaerobic digester, to a research and development centre.
Consistent with the holistic plan, Zamri said waste separation has a key function as the WTE plant works in tandem with the centre.
Non-combustible material such as metal and concrete recovered from the incinerator will be sent to the centre’s material recovery facility for construction and demolition waste, while organic waste from restaurants and hotels will be directed to the centre’s composting plant.
However, despite technological advancement, old-fashioned recycling and waste separation is still a necessary practice, with the public playing a vital role, said Zamri.
Once the first and second phases are up and running, the centre is expected to generate 60MW of electricity daily, which can power up to 60,000 households a day.
The Integrated Solid Waste Management Centre now handles waste from six municipalities in central areas of Selangor, and Zamri said future plans would involve setting up at least two more of such centre, believing that three WTE facilities would be required to sufficiently cope with Selangor’s waste.
“We are also planning a centre at our other landfill in Tanjung Dua Belas in Kuala Langat that caters to waste from the Kuala Langat, Sepang, Kajang and Putrajaya areas.
“We also proposed another in the north, near the Selayang and Hulu Selangor – our target is to achieve all this by 2025.
“I think it is doable with the federal government’s manifesto to bring renewable energy from currently around 3% to 20% by year 2025.
“With these, we hope Selangor will no longer have giant landfills that handle a few thousand tonnes of waste, with all the waste instead going to integrated centres,” said Zamri.
He cited Singapore which does not have landfills on the island, only WTE plants.
Whether WTE is the solution to our problems or just a temporary patch, time alone can tell.
The only certainty is a need for change and the urgency of handling the problem before it gets out of hand.
And right now a holistic strategy at least sounds like a possible step in the right direction.