Tofu waste powers Indonesian homes

tofu vats
CC BY-NC 2.0 candice and jarrett

In the village of Kalisari on the island of Java in Indonesia, about 150 tofu producers have begun turning their wastewater into clean energy for their village.

To make tofu, a lot of water is used to turn soybean into the humble beancurd that is a staple of Indonesian diets -- about eight gallons for every two pounds of curd. Acetic acid is added to the water to help make the tofu clump together. After being stirred in boiling hot cauldrons until turning into the right consistency, the water is drained and the tofu is sliced into cubes. Until recently, that water was just waste that was dumped out, but now the tofu producers of Kalisari have joined a project that puts that wastewater to much better use.

After it is drained, the water is treated with bacteria in digester tanks to create biogas. That gas is then piped directly to household stoves in the village that have been modified for the fuel where it is then used as clean-burning cooking gas.

Before using the biogas, villagers had to wait for deliveries of tanked gas or use wood for their stoves. The gas deliveries are sporadic, with villagers often having to wait weeks or go an entire month without it. Now, they have a consistent fuel source for cooking and it's also three times cheaper to pay for the unlimited biogas than the refillable liquid propane gas tanks.

"One month you had it, another one you didn't. Thanks to this biogas, things are a lot easier for people here," Waroh, one of the tofu producers, told AFP.

The local government hopes that the gas will soon power lights in the village too as bigger digester tanks are being built to serve more residents and produce more biogas.

The other major benefit is that this project keeps the wastewater from tofu production from polluting the environment. The wastewater used to be pumped into nearby rivers which contaminated the waterways and the rice fields downstream. Now that the waste is being sent to digester tanks and converted into biogas, the villagers have already seen an improvement in water quality and rice yields.

This renewable energy project is one of many small scale initiatives taking place in Indonesian to cut down on the nation's heavy fossil fuel use. The government has committed to getting 25 percent of their energy from renewable sources by 2025. It's currently one of the world's greatest greenhouse gas emitters.

There are many thousands of tofu producers throughout the island nation. The government says that if this project was rolled out nation-wide, more than 56,000 tons of fossil fuels could be replaced with biogas every year.

Tofu waste powers Indonesian homes
The wastewater from tofu production is now being used as a biogas in a Javan village.

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