Assessing the Performance of Small Scale Greywater Treatment Systems under Controlled Laboratory Conditions

A comparison of chemical versus biological package greywater treatment systems was undertaken using a new laboratory based protocol that included a synthetic greywater formulation that mimics average bathroom and laundry greywater in Australia. The results for chemical, nutrient and metals removal showed that the treatment systems behaved very differently under the test conditions. The chemical system was able to remove most of the components of greywater that could be detrimental to the environment and produced high quality product water. The biological system was only able to remove some of the components of the greywater, and did not produce the same quality of product water. However, the product water quality was found to improve continually over the duration of testing. It was concluded that for the current composition of Australian greywater the chemical based technology produced the highest quality product but that other environmental costs, such as chemical use and energy also need to be assessed. If greywater compositions change with the use of more biodegradable, low environmental impact personal care and cleaning products, biological treatment systems may be better suited to treating greywater in the future.