Towards water security: How to set up a greywater treatment system

This summer, Bengalureans faced another gruelling water crisis. So much so that residents even in core areas of the city had to start buying water from private tankers. And in outer areas, even private tanker supply was inadequate.

We had earlier published a guide on building recharge wells to capture rainwater this monsoon. Another way to meet your water requirement is by treating and reusing the greywater generated in your household, especially if you live in an independent house.

What is greywater?

Greywater is simply soap water; it's the wastewater from bathrooms, washing machines etc. Greywater does not contain much organic matter, and the major contaminant in it is phosphates from soap. In contrast, blackwater – which is mainly wastewater from the toilet and kitchen – contains organic matter and pathogens.

Since greywater has fewer pathogens, it is easier to treat and reuse, especially at a domestic scale. On average, a four-member household generates 360 litres of greywater daily.

Why treat greywater?

How to set up a greywater treatment facility?

There are different methods to treat greywater. The one discussed here is a natural treatment system that uses a reed bed. You can set it up either on the rooftop or in the plot around your house. Consult a professional to decide on the specifications and location of the system.

The main components of the system are:

How is water purified in the system?

Here's a video explaining the treatment system in a plot. If you install the system on the rooftop, the treated water can be used for terrace gardening. Here is an example of a rooftop system that is used to grow rice on the terrace.

How much do they cost?

Setting up the system in a plot cost Rs 50,000 – Rs 1,75,000, as of early 2017.

Keep in mind

Find more details on setting up the system here.

[This guide is based on material originally published by Biome at the Urban Waters website]