Detergent is everywhere and used every day in life. Bath, dish and clothes washing, toilet flushing. But detergent providers care less about how to use the post detergent water after washing. To design a collection of detergents formula, adjusting the formula along with other factor changes can help us get other benefits besides washing; for instance, compound fertilizer. I take the home washing water as an example.

Object 1
From washing sewage, it is easy to separate pure water and impurity.
Process:
Based on washing target, affirm one pair of certain washing detergent and its filter method. Requirement, in many washing cases, we have to repeat washing with water, so we can filter the sewage into clean water. A lot of water can be saved.
Scenario:
Wash one target once more (cloth). Wash many similar targets (dish).

Object 2
Washing sewage is used to flush toilet and at the same time wash the toilet.
Process:
Washing sewage dissolves urine with one flush.
For defecation, washing sewage not water deal with it.
And then store some washing sewage as a usual resource.
Requirement:
2.1 the washing sewage can keep chemical stabilization for some weeks, little smell and simple color
2,2 one unit washing sewage can dissolve urine with many units. After dissolving the mix solution does not have a heavy smell and has acceptable color.
2.3 the washing sewage can dissolve defecate particles from toilet inner wall alone with little smell. 

Stakeholder:
Somewhere with flush toilet can produce washing sewage constantly, such as a house or hotel.

Object 3
A compound fertilizer from mix of washing sewage and urine. The compound fertilizer can help to create soil of one location.
Process:
Based on soil creation process, select the recipe of fertilizer. From fertilizer recipe, we can calculate the detergent recipe and washing chemical process.
Requirement:
A simple and small scale chemical process in washing process and post process.

Stakeholder:
House, sewage treatment plant, farm.

Potential benefit
No large investment, easy to deploy.
If the compound fertilizer cost is lower than now, many poor can own toilet freely.
Water and sewage quantity reduced significantly. Water crisis relieved.
A city house decrease the dependency of the upper and lower water pipeline system.
Alone with the distributed energy technology, we can construct and deconstruct a building and community anywhere.

Market
House, hotel, farm. Anywhere washing sewage is produced.

How to produce
For every single scenario, we design the detergent recipe with simulation and experiment.
Similar to other detergents, it can be produced in a factory.
For consumers, we build the supply and recovery chain to form close circle more and more.