Powering the Mekong with rice husks

As the search for alternate sources of fuel continues in earnest, Vietnamese scientists have found great potential for a source of power in the scourge of the Cuu Long (Mekong) Delta rivers – water hyacinths and rice husks. Hoang Vu and Van Dat report.


Big rod of power: Nguyen Van Vu explains the working of a rice-husk-firewood machine. — VNS Photos Le Hoang Vu


Price is right with rice fuel: Cui trau or rice husk wood is easy to burn, releases almost no smoke and causes no pollution.


Husky: Farmers pack rice husks into bags before selling. — VNS Photo Vu Huyen


Basket-case: A farmer carries rice husk from a rice husking factory in Co Do District, Can Tho City to a boat. The husk is being turned into a fuel-rod in the delta.


Useful weed: Water hyacinth being collected in Hau Giang Province. The weed is now used to make handicraft items and generate biogas in the southern provinces.

Flour mill owner Le Minh Truong was struggling with the dramatic increase in coal prices.

The Can Tho City entrepreneur was beginning to wonder if his business would survive when word reached him about scientists in his own neighbourhood producing a new kind of fuel – cui trau (rice husk firewood).

Truong needed no second introduction. "I knew exactly that I needed this material for my business."

Every day now, he makes his way to Hau Giang Province’s Phung Hiep District to buy five or six tonnes of cui trau at VND1,000 per kilogramme for drying flour produced in his factory.

Truong has plenty of company.

Other flour mills, pottery and brick kilns in nearby provinces and HCM City are also sold on the newly invented fuel. Most of them say it is easy to fire, releases almost no smoke and causes no pollution. Fire from the fuel lasts even longer than from coal.

The story of how a waste product from rice farming – that was a headache for rice mills, fishermen and fish breeders in the Cuu Long (Mekong) Delta – was transformed into a much-sought after fuel, begins with an unknown farmer in Tien Giang Province.

It is known that this used to be a popular source of fuel in South Korea and China before the unknown farmer reinvented the machine that made the "husk firewood".

And like the reinventor, the machine would have languished in relative obscurity were it not for engineers from Can Tho University who bought it and used biogas instead of electricity to operate it.

The waste and weed

With the world plunging from one energy crisis to another, people and governments the world over are seized by the need to source fuel by alternate means.

The Vietnamese government got into the act as well, encouraging projects to exploit biological combustibles to replace traditional firing methods in order to achieve energy security and ensure environmental protection.

Nguyen Phu Cuong, deputy head of Science and Technology department under the Ministry of Industry and Trade, says the Government approved a scheme to develop biofuels through 2025.

As a result, biogas generated from animal waste, bio-diesel produced from rice, maize, manioc and sugar cane, or ethanol from tra catfish grease were researched and began to be applied around the country.

However, rice husk and water hyacinth, the waste and the weed found every where in Mekong Delta, fell below the radar.

The delta’s waterways continued to be polluted by the illegal dumping of rice husk and clogged by the floating weed, water hyacinth.

A recent investigation found that rice mills in Hau Giang Province annually release 220,000 tonnes of husk into the water. While farmers in rural areas have known how to use rice husk to cook their meals, they had been discouraged by the time, effort and money needed to carry and store it.

Nguyen Van Don, owner of a rice mill in Dong Thap Province says that before 2004, when ceramic, brick making business used rice husk for firing their kilns, farmers also used it to cook their meals.

Then he did not have to release the husk into the rivers, and was actually able to sell the waste to traders at VND350 a kilogramme. In one season, he could earn VND150 million ($9,375) from the sales.

With the rising popularity of coal, gas and other advanced fuels, rice husk fell out of favour, and he had no choice but to dump them in the water despite knowing that it was illegal, because he had no space to store it.

In An Giang Province, where there are around 1,000 rice mills, the situation is similar. One mill owner, Tran Thanh Hon, recalls that in the past, rice husk traders had to plead to get the waste at VND70,000 ($4.4) per tonne, but now, factory owners cannot find takers even though they are willing to pay people to move it out.

Fish breeders are among the victims of this dumping practice, claiming that the resultant water pollution is killing their fish.

For several years, water hyacinth on Mekong Delta waterways was used to feed livestock or poultry, or making handicraft items, but there was still too much of the floating weed.

Now, with this rediscovery, rice husk and water hyacinth are enjoying a renaissance.

Timely innovation

Nguyen Huu Phong, an engineer from the Hoa An Biological Research Centre under Can Tho University, is one of the team of scientists behind the new machine that makes cui trau from rice husk and water hyacinth.

The machine, costing VND15 million ($937), uses a three horse-power engine to make 80 kilogrammes of the new firewood an hour. Around 105 kilogrammes of rice husk will yield one kilogramme of firewood.

The cylindrical firewood pieces are about 73mm in diameter and 0.5 to one metre long each. One kilogramme of this firewood can be used to cook meals for four people for a whole day. The product is being sold to farmers at VND1,000 per kilogramme. Many people say the price is too expensive for farmers.

But Phong says heat from the new fuel will last longer than that of coal, adding that since the factory opened, many people from central provinces, Tay Nguyen (Central Highlands) and HCM City are buying the firewood daily.

Most businesses that used to burn coal to heat their boilers now use cui trau thanks to its reasonable price and higher capacity, not to mention it causes less pollution.

Phong says the centre is not able to meet the demand of enterprises. Many business owners from HCM City consume between seven and eight tonnes a day.

Phong says the plan is to make the prices even lower and increase capacity by transferring the technology to every household in the delta and encourage rice mills to put to good use their waste. Most importantly, the new fuel will help many families save money and reduce the negative impacts of using coal.

Local authorities estimate that the Mekong Delta annually produces some 3.6 million tonnes of rice husk. The need is obvious, therefore, for more machines to process it and present residents and businesses with a cheaper, more environmentally friendly fuel. — VNS

(21-09-2008)

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