Did you know that a 2007 Kapiti Coast study found that 50-60% of all household water was used in the laundry and bathroom for washing? This equates to 106,000 litres of water per year in a typical home. Recycling grey water for garden irrigation could reduce both the demands for mains water and wastewater treatment
Grey water is the name given to the wastewater that we generate when we bathe, shower or do the laundry. This is very different from black water or sewage that flows from our toilets. For a time all wastewater in Whanganui was discharged directly into the Awa. Now, after separation of the storm water, the wastewater generated in the city is processed through the Airport Road waste treatment plant (or soon will be again) and discharged into the ocean, 1.8km offshore.
One of the things that struck us as a group was why do we mix our toilet waste with our bath water and increase the amount of black wastewater that has to be processed? Grey water might not be the highest quality water but what if it can be cleaned enough to use it again for other purposes like watering gardens or even recycling it to flush the toilets? This is what our Y10 STEM (Science, Technology, Engineering and Mathematics) students will be investigating over the course of the year.