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Tuesday June 21, 2011

From waste to energy

Cow pats, chicken droppings, mill effluent and even household trash – all can yield energy.

ON a small hilltop with sweeping views of farmland dotted with trees and tin-roofed structures, a herd of cows are grazing. In a shed nearby, more cows are lined up along a trough full of grain, seemingly enjoying the scenic view as they chew their food.

A few months ago, this idyllic spot was marred by the overwhelming stench of decomposing cow manure. When farm hands hosed down the cow shed, rivulets of manure ran out and spread across the grass. That attracted an army of flies – unhygienic and unwelcome company for those operating the small dairy farm in Semenyih, Selangor.

The government-owned plot was designated as part of the state’s Permanent Food Production Park under the 3rd National Agricultural Policy. Last October, the Veterinary Services Department decided to use it for a pilot project. They commissioned the installation of a small biogas plant there to ensure proper waste disposal. The department also wanted to look at how green technology might be used to pursue the “zero waste” concept. The result has not only been a drastic improvement in hygiene, but ample power generation for the farm’s electricity demands.

Source of energy: A typical poultry farm with 1,000 chickens can generate up to 100 tonnes of droppings a day. That much waste can produce enough gas to generate 1MW of electricity.

William Tan and his partner Lim Kuang Yong are both directors of SP Multitech Renewable Energy. They built the biogas facility at Semenyih at a concessionary price – RM60,000 instead of RM100,000.

It seems that after decades of non-governmental groups pushing for a greener approach to the world’s energy needs, market conditions are finally falling in favour of the alternative energy sector. Up until recently, it had economic odds stacked against it.

“There was an attempt to push for biogas technology about six years ago,” Tan says. “However that was largely unsuccessful. It was just too expensive and local farms didn’t see any sense in investing.”

Part of the reason for the high cost was because parts had to be sourced from foreign companies. Due to a lack of demand and local expertise, there were no local suppliers.

Inside this chamber built underneath the dairy farm in Semenyih, bacteria digest sludge, generating gases that can be used directly for energy or converted to electricity through a power generator.

Over the years, however, the biogas sector abroad has matured and technologies have gotten cheaper and more efficient.

At the same time, dwindling fossil fuels, the rising cost of non-renewable energies and feedstocks, climate change, and a shift in national policies have led to a proliferation of green-tech entrepreneurs. The push and pull factors are making renewable energy solutions such as biogas look like logical next steps.

Know your technology

Tan, who has taken me on a short drive from his office in Puchong through a bumpy road to the farm in Semenyih, leads us to a small concrete room adjacent to the cow shed. He opens the door to reveal an inflated balloon about half-metre wide and over a metre high. It sways from side to side as gases, produced by a constant series of microbe-driven chemical reactions taking place in a large vat underground, are pumped in.

William Tan

In the vat, various colonies of bacteria are anaerobically digesting a large pool of sludge, fed by a drainage system that allows fresh manure to be hosed straight down from the cow shed into the digester. According to Tan, these microscopic single-celled organisms are key – they are the core of the technology. Tan has partnered with German company Bio-H2 Energy to develop the biogas sector here.

“Biogas is very established in countries like Germany,” he says, referring to the 6,000 biogas plants that dot that country’s landscape. “Their technology is really advanced.”

Government policies and incentives have helped the German biogas sector grow. No livestock slurry or crop goes to waste. Instead, they get converted into energy that is used to power farms and any excess is fed into the national grid. Meanwhile, the well-digested slurry makes high-grade fertiliser.

Tan explains that botched past attempts (because of the backyard technologies used) have scared people away from biogas production. He says getting the technology right is important for success. This includes having the correct method to extract and treat hydrogen sulphide to prevent corrosion of machinery.

It is also important to know your substrate – failure to extract sand out of chicken droppings (sand is part of the bird’s diet as it contains calcium carbonate that is needed to produce egg shells) for example, will clog up the biogas digester.

“The key is having the right substrate-specific bacteria, and these must be sourced locally. We had to invest in research to identify the most optimal local microbe strains and culture them,” says Tan. His team took two and a half years to identify the perfect combination of bacteria.

In the digesters, these carefully selected bacteria excrete enzymes that break down the sludge into soluble organic constituents which they absorb as food. During this process gases are generated.

Hydrogen sulphide (one of the things that makes rotting manure stink), nitrogen, hydrogen, methane and carbon dioxide therefore get trapped in the airtight digester along with any unpleasant odours, constantly filling up the balloon.

Free energy

At the Semenyih farm, the biogas is put to good use. Farm hands take hot showers under a gas-powered water heater. A series of pipes channel the gas from the balloon to a gas-powered cooking stove, a rice cooker and water boiler. There is also a generator which converts the gas into electricity for lighting and vacuum pumps used for extracting milk from the cows.

The digesters produce enough gas to generate 5kW, but because the energy requirements of the farm are low, a good deal of the gas is actually burned off. There is potential for all that extra energy to be channelled back to the grid but only if the facility is located sufficiently close to an electrical substation, which this farm is not.

When empty fruit bunches and palm oil mill effluent decompose, they generate methane. The gas can be harnessed to produce energy.

In this particular situation, the main advantage is the proper management of cow manure to create healthy and hygienic working conditions, with good quality fertiliser and electrical self-sufficiency as the end products.

For the Veterinary Services Department, this is more of an experimental venture. Deputy director-general (development) Datuk Dr Ibrahim Che Embong says they are monitoring the progress of the plant, particularly on how much energy it produces.

There are no plans laid out for the future yet, but the potential is undeniable. Considering that there are over 20,000 cows, 77,000 chickens, 8,700 ducks and 880 pigs currently being reared in the country, there are a lot of places where biogas plants can be put to good use.

And with the biogas technology soon to be available at local prices – SP Multitech Renewable Energy plans to locally manufacture the components early next year – there is even more reason for companies to adopt the system.

Green eggs

Within the private sector, one of the first to test the water is QL Poultry. Churning out about three million eggs a day, it is one of Malaysia’s leading poultry egg producers and a subsidiary of Bursa-listed QL Resources.

SP Multitech is currently building a 500kW capacity biogas plant at its poultry farm in Pajam, Negri Sembilan. The targeted completion date is by year-end.

Motivating factors for building the facility, according to QL Resources executive director Chia Mak Hooi, include turning around expenses for chicken waste disposal into a source of revenue through biogas energy production and organic fertiliser sales.

He estimates savings of up to RM100,000 per month. He says turning his plant into a zero waste operation will also allow the company to do their bit for the environment, which they can market by stamping their eggs with a “green label”.

“There will be high initial capital investment and there is the worry of failure seeing we are the first company to venture into this,” admits Chia.

However, he also sees this as a chance for his company to take the lead in greening their business. If they are successful, he hopes more private companies will be encouraged to adopt the technology.

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