VACB Model

Later during the morning of the 18th, after visiting the rice noodle business, the boat drove us further down the river for another fifteen minutes or so to a pig farmer’s house.  The farm was run according to a VACB model, which is short for Garden – Pond – Livestock – Biodigester System.  This model basically provides a waste management protocol for farmers living in the Mekong Delta.  

Behind his house, the farmer had three concrete pig pens.  One held a huge pregnant pig and another pen had about eight three month old pigs.  Each pen had a small hole, about three inches in diameter, in the corner so the manure could be washed out.  The waste is then collected in the biodigester where it is broken down and composted.  The biodigester looked like a big white plastic tube that’s about two feet wide and more than ten feet long.  His biodigester was installed nearly 16 years ago and he hasn’t had to replace anything, besides the outer plastic covering.

Feeding the pigs.

Biodigester at the first farm.

 As the waste breaks down, some of the organic matter is fed into a pond for the farmer’s  fish to eat.  The rest of the solid compost is used as fertilizer.  The family also collects the methane gas that the biodigester produces and uses that gas for cooking.  Families that don’t have methane gas to cook have to buy or collect wood every day.  It saves the women a lot of time and they don’t have to breathe burning wood every day.  They use huge bags to hold the methane gas and have tubes to carry the gas into the kitchen.  I was wondering why they didn’t explode and the farmer explained that the bags have a system which measures and regulates the amount of gas.  If there gets to be too much methane, the bag will gradually disperse some, preventing an explosion.  Another advantage of having a biodigester is that the pig pens don’t smell since the waste is removed frequently throughout the day.  I was surprised that the biodigester itself didn’t smell either.

The bags that collect the methane gas used for cooking.

The farmer's cooking stove using the methane from the biodigester.

The biodigester seemed like a great system for all small farms to have, but not every farmer supports the VACB model.  Before installation, each farmer needs to have the initial capital of $200.  That might not seem like a lot, but for a country where the average yearly income is $1,100, this payment is almost impossible.  Also, the price of pigs fluctuates a lot in the market so many farmer think it is too risky.  

The farmer we visited said he could sell his pigs once they reached 120 kilos, which would take about six months.  He estimated he would receive 36,000 dong per kilo (about $1.00 = 20,000 dong), so the farmer would earn about $216 per pig.  But out of the farmer’s total pig profits he earns only 15 – 20% because he has to subtract the price of pig feed.  Besides raising pigs, many farmers also have other means of income.  The farmer also raised fish and earned about 60% of his total profits, making around $2,000 per year.  He also had fruit trees and he received 100 % of the profit from the produce, receiving about $750 per year.  But keep in mind this farm was an upper income level farm and many farms in Vietnam do not share the same profits.

After lunch, the farmer took a classmate and me around to visit two other nearby farms while everyone else took a nap.  One had a biodigester installed five years ago by past SIT students.  They built it in a day and it is still working fine.  Then the farmer took us to a farm without a biodigester to see the difference.  The farm also had concrete pig pens, but no pond.  The backyard was extremely muddy and smelled of feces.  The women working explained that they try to wash the pig manure out into a nearby stream that connects to the river, but instead of reaching the river, the waste usually backs up onto the lawn.  

Backyard of the farm without the biodigester.

This way of farming is environmentally harmful and very unsanitary for the humans and animals and results in more diseases.  They were aware of the benefits of having a biodigester, but those farmers didn’t have enough money for the initial payment.  Without the biodigester and methane gas, they still had to collect and burn wood to fuel their cooking stove.  

 SIT has built over 15 biodigestors in that village and 3 in Hoa An.  Next week, my class will get to build one at a farm in Hoa An, so that should be fun!

Anna and I with the first farmer who showed us around.