Water and the Circular Economy
Project Round
Project Number
62M - 2025
Research Organisation
RMIT University

Removing Effluent Colour by Advanced Treatment

The Challenge

Investigation of the sources of colour to Eastern Treatment Plant (ETP) by South East Water showed that a relatively small number of industrial plants contribute a large proportion of the brownish colour to the secondary effluent.

The objective of this project was to investigate the feasibility of and to compare coagulation, ozonation and UV/H2O2 treatment, separately or in sequence, for the removal of colour from wastewater before and after anaerobic treatment.

The Project

Examination of the major sources of colour to the ETP indicated that one industrial plant contributes approximately 20 per cent of the total colour load which is most likely due to the use of melanoidins.

Samples of wastewater and anaerobically treated wastewater were collected from the target industry and delivered to RMIT University for analysis. The raw and anaerobically treated wastewater was characterised in terms of pH, colour, DOC, COD, UVA254.  A number of physico-chemical treatment processes were then tried and their performance evaluated.

The Outcome

The effectiveness of physico-chemical treatment on colour removal from the raw and anaerobically treated wastewater from an industrial plant was investigated. As there was a large variation in the chromophoric properties of the water between samples, the efficiency and optimum treatment conditions varied. This would need to be taken into account when implementing a treatment process at the industrial plant.

The results obtained from this work demonstrated that anaerobic treatment followed by ozonation may be suitable for the treatment of wastewater from the targeted industry. However, this is dependent on the consistency of the chromophoric properties of the wastewater and further trials need to be undertaken to determine a range of characteristics of the wastewater and anaerobically treated wastewater, whether coagulation is necessary, and the ozone dosages required for consistent colour removal.


Supporting documents