For people living in some remote villages in Indonesia, heating houses and fueling stoves can be a real challenge. The resources required, like gas and wood, have to get shipped in and distributed to individual households, and not only does this process take a lot of time - some families wait weeks for new gas to arrive - it also produces a ton of emissions that contribute to global warming.

The good news is that this antiquated system is now on its way out, thanks to an unlikely source: tofu.

In Indonesia, tofu isn't just a snack - it's a livelihood, with hundreds of small, family-run shops producing tofu in massive quantities every day.

Now, thanks to a government-run program, the waste water from all that tofu production is getting transformed into biogas that can be pumped directly to houses.

Tofu has been made the same way for generations, and it's a rather simple, yet time-consuming process.

Basically, producers start by soaking and grinding soybeans to separate the soy milk from the soy pulp. This step takes the longest because the beans have to soak for hours before they are ready for separation.

After the separated parts go through a filtration system, the protein and oil are separated from the soy milk. A chemical coagulant is added to firm everything up. Once formed, you have tofu ready for cutting.

Though simple in practice, an enormous amount of water is required to make tofu - roughly 33 liters for every kilo of spongy bean curd.

Researchers found that this waste water could be turned into biogas if a certain type of bacteria is added to it.

Every day, the waste water is collected from various shops and treated with bacteria. Once transformed, the gas is pumped directly to local homes.

Besides creating a green energy source for locals, using all that waste water has significantly helped the local environment. Thousands of liters of waste water drained from raw tofu was once pumped daily from factories around the village into nearby rivers, befouling waterways and contaminating rice fields downstream.

Words to Learn 相关词汇

排放

páifàng

emission

a substance, fluid, etc., that is emitted, discharge

污染

wūrǎn

contaminate

make impure by contact or mixture with something unclean, bad, etc.

豆腐为印尼提供清洁能源

在印度尼西亚的一些偏远小村庄中，房屋取暖和锅炉燃料是个大问题。像天然气、木头之类的资源需要从外面运输进来，然后再送到每个家庭。这个过程很漫长，许多家庭要等好几周，而且运输会产生大量的二氧化碳，加剧全球变暖。

好消息是，这种陈旧的方式将被取代，这多亏了一种不同寻常的来源：豆腐。

在印尼，豆腐不只是一种食物，更是一种营生，成千上万的家庭式小作坊每天要生产大量的豆腐。

如今，当地政府主导了一项工程：将所有做豆腐剩下的水用来生产沼气，然后供应给各家各户。

少年来，豆腐都是相同的做法，过程简单但是耗时。

简单来说，就是要浸泡然后研磨大豆，把豆浆和豆渣分离。这个步骤耗时最长，因为需要将大豆浸泡数小时才能实现分离。

分离出来的豆浆经过过滤，蛋白质和油脂就分离出来，然后加入混凝剂就形成豆腐了。豆腐成形就可以切块了。

尽管操作过程简单，但制作过程中需要大量的水，大概每公斤豆腐需要使用33升水。

研究人员发现，如果在这些废水中加入某种细菌就可以将废水转化为沼气。

每天从各个作坊收集的废水被集中到一起，然后在里面加入细菌，随后就能产生沼气，即时供应给当地住户。

这个方法不仅为当地提供了绿色能源，而且合理地处理废水保护了环境。此前，每天制造生豆腐产生的成千上万升废水从村中各处的作坊排放到附近的河流中，污染了河流和下游的稻田。