We make and provide biogas systems that local farmers handle, which in principle is a sewage treatment system, similar to a septic tank. According to data provided by the Indonesian government, 30% of households in Indonesia lived without toilets as recently as 2015, just seven years ago. Even when they did have toilets, only 10% were equipped with a proper treatment system such as a septic tank.
When I first came to Indonesia 30 years ago, I went surfing on Nias Island off the coast of Sumatra. I got up with no electricity or running water. When the sun rose, I surfed and went to bed when the sun set. We slept in huts made of woven bamboo without toilets. We had to dig a hole behind the hut to do our business.
A little more advanced would be a toilet without a disposal system, as shown in this photo, with no concrete surface underneath to catch the faeces and urine, which would then seep into the ground and pollute the groundwater. In the centre of Bali, there are not many toilets like this anymore, but the standard toilet is just a concrete box underneath the toilet. Most of the villas and hotels in Canggu, where I live and where there are many hotels and residences for foreigners, have only this concrete box under the toilet to store the sewage that comes in.
For example, one of my staff, who used to work for me and is a bit older than me, said, "Since I built my house ten years ago, I have never had to pump sewage out". The reason why they have never pumped is that the sewage seeps through the concrete and flows underground. Concrete is not waterproof unless it has been treated so that liquids will seep into the ground. Furthermore, most buildings in Bali are made of concrete that has been kneaded by hand at the construction site, and because construction is often lax and earthquakes are common, many of these buildings likely have cracks. Some of the domed concrete biogas digesters have cracks in them. Sewage is flowing underground from the cracked concrete tanks. This is the current situation of sewage treatment in Bali.
We are now thinking of a project to improve this situation.
One more thing is SDG 6, Clean Water and Sanitation. In developed countries, water treatment is already a thing of the past, and we don't hear much about liquid waste from factories, either. So people in developed countries may not know why clean water and sanitation are in the same goal in SDGs.