The experimental project herein undertaken endeavors to explore grey-water reuse by way of setting up a circulation system where the water undergoes a process of filtration before it is pumped back to the house for use in toilet flushing. It is hypothesized that such an innovation will go a long way to reduce the municipal water demand and consequently the household water bill.
The flip side of this study focuses on assessing the suitability and impact of using greywater in small scale subsistence farming. Agriculture being regarded as the largest consumer of water in South Africa and the world at large, consuming up to about 70%, of the total amount of water extracted from fresh water resources (Gago et al, 2015; NWRS2, 2013), there remains a dire need to innovatively use water in the production of food to mitigate the water scarcity challenge without compromising food security. Food production at household level presents one of the strategies for increasing food security and nutrition (Selepe, Mtyingizane & Masuku 2015). The extreme lack of rainfall in the country has led to water scarcity for food production and has tremendously impacted on quality of lives as water affects human livelihood in a number of ways.
As an extension of the afore mentioned engineering design where grey water is circulated to the house for toilet flushing, excess grey water shall be directed to a drip irrigation system that will be installed for a 10m by 10m plot in the backyard for cropping activities. The use of grey water is envisaged to be one of the ways that can be employed to alleviate pressure on the scarce water resources. There are however some concerns on the use of grey water regarding possible adverse effects on human health, plant growth and yield on the environment especially on the continued support of soil to support plant growth (Nicola, Carden & Armitage 2010). It is therefore imperative that a thorough filtration process be pursued for the betterment of water quality. The filtration system shall be comprised of sand, gravel and biochar as filtration media. The experiment aims to provide insights into the efficacy of the filtration media (biochar in particular) to filter water to an acceptable water quality standard. A series of water quality tests will be conducted with various combinations of sand, gravel and biochar of different sizes juxtaposed with flow volumes and duration of stay of media in the system. The Irrigation water quality guidelines shall be the yard stick against which water quality will be measured.
The study is being conducted from Fort Cox Agriculture and Forestry Training Institute (in the Eastern Cape Province) as a student experimental project. The project forms part of the curriculum innovation work which was prompted by the Amanzi for Food projected rolled out by Rhodes University and other stakeholders.
By Chamunorwa Matambo