This research investigated sustainable and effective ways of managing the growing water and wastewater problem by research to represent reclamation and use of grey water from baths, showers, hand basins and washing machines for plant irrigation. A detailed review on grey water characterisation from past research, showed that grey water is polluted, and the quality is not like domestic wastewater and therefore the traditional design criteria, guidelines and standards used for wastewater cannot necessarily be used for grey water reclamation.
The review from past research shows grey water with detergent characteristics was cloudy, coloured and had excessive bubble formation, that could reduce the willingness to use the water, especially for in-house uses. Grey water has harmful chemicals that may cause harmful effects to the growth of plants and could degrade soil structure.
Globally there are standards for potable water quality, that are widely employed, whereas only a few countries have non-potable water quality or grey water reuse standards. Therefore, standards such as WHO guidelines, UK/EU bathing water standard and EPA water standard for WC flushing were used as guidelines in this research.
Possible natural and waste materials were used to remove the pollutants. Initially bench top stirred batch reactors were used to study the removal efficiencies of the materials in the removal of pollutants. Then, these were followed by meso-flow column adsorption experiments, that were carried out using single adsorbing materials. The materials that had better removal efficiencies were used for a material combination experiment. The material combination experiments were carried out at bench top level, and the final best combination was selected, for the final adsorption treatment system. Prior to the final treatment experiment, an initial plant trial was carried out to study the effects of grey water, tap water and roof harvested water on plant growth and health and roof harvested water as a nutrient rich irrigation source of water. The roof harvested water plant showed the highest growth compared to tap water and grey water irrigated plants. There was not much difference between the final growth (final mean height) of tap water and grey water plants. The fruits from grey water plants were delayed by two weeks compared to the fruits from tap water plants and roof harvested water plants.
The final treatment system was proposed, designed and constructed to incorporate the final material combination. The final treatment system was combined with a plant experiment, to study the effects of grey water and treated water on plant growth, productivity and soil condition. The final adsorption treatment not only removed the sodium from water source (grey water) but were also capable of enhancing the resulting irrigation water quality, by increasing the magnesium and calcium in the treated water, benefitting the plants as well as the soil. The treated water irrigated plants and tap water irrigated plants showed higher growth compared to grey water irrigated plants.
|Date of Award||10 Oct 2022|
|Supervisor||Alan Newman (Supervisor), Steve Coupe (Supervisor) & Fredrick Mbanaso (Supervisor)|
- roof harvested water,
- waste materials,
- natural material,
- treatment system