AbstractThis thesis evaluates the Oxidation Ditch as a form of domestic effluent treatment. It uses as its basis a survey of the performance of existing plants in operation and reflective site trials of an existing plant in operation.
Based on the survey of existing plants, the design elements of the Oxidation Ditch are considered with the view to concluding scope for improving the design factors and the process.
The ditch was found to be extremely process efficient, with little scope for improvement. However the ditch was also proven to be generally over designed with opportunities to make significant savings in capital and running costs without deterioration in the quality of the final effluent.
In particular, an excessive use of oxygen was proven, which was found to have no process advantage, but a financial disadvantage when considered in relation to the cost of energy for operating the mechanical plant.
A series of tests were undertaken on an existing plant in operation, with the view to testing the conclusions emanating from the survey. These tests reaffirmed the scope for making savings both in the capital and running costs of the Oxidation Ditch. The excessive use of oxygen was further proven unnecessary, for although the effluent nitrified and denitrified, there was still evidence of oxidised nitrogen in the final effluent, with the resultant discharge of some pollutants to the receiving water course.
The design parameters of the guiding Technical Memorandum have also been considered in depth and alternatives are presented based on experience for use by the practising engineer.
This thesis contributes to current knowledge and practice by highlighting those areas where substantial opportunities exist to effect savings in both the capital and running costs of the Oxidation Ditch plant. These savings could also lead to an improvement in the final effluent and impact on the receiving water course.
|Date of Award||Aug 1991|