The Septic System

Human waste to crops

The nutrient rich effluent produced through a septic treatment system is used on the fields to enhance the crops, and also provides some financial relief from having to buy expensive fertilisers.

The septic tank system works by:

• collecting human waste through the toilet pan which is dip flushed using less than one litre of water 
• waste passes through the first chamber of the septic tank where solid waste is treated
• only liquid passes through to the second chamber where further settlement of remaining solids occurs 
• nutrient rich effluent is piped underground from the second chamber to the surrounding crops and is a valuable fertiliser.

Approximately every ten years the accumulated sludge from the first chamber needs to be removed, which also provides valuable additional fertiliser.

The animation above was developed to show construction teams and villagers in Nepal how a septic tank works. Less than a year after releasing the animation it has had over 70,000 visits on YouTube.

The toilet building

Collecting rainwater

The biogas system