Study On Modified Integrated Oxidation Ditch Wastewater Treatment Process

The Modified Integrated Oxidation Ditch process (MIOD), which is based on Integrated Oxidation Ditch (IOD) and developed from it, is a highly efficient, energy saving, simplely-running wastewater treatment process. Based on the model experiment, flow performances of the main ditch and operation styles of MIOD are experimented and furthermore, energy efficiency is analyzed in the article.Based on the test of velocity in the main ditch, the trend of its velocity and easy deposition areas are analyzed, and measures to make its flow performances are taken. It is put forward that setting up flow guide boards properly in front and at the back of the aeration equipment is a simple and efficient means to make flow performances better. The results show that flow guide boards make full use of high energy at the back of the aeration equipment, which improve the average velocity of the main ditch and lessen the easy deposition areas.Given specific hydraulic retention time, proper distribution rate of raw water and specific sludge retention time, the styles of two operations (continuous flow continuous aeration and intermittent aeration) are studied in the article. The results show that MIOD can achieve good results and run steadily. Based on the determination of aeration-pausing time and the analysis of oxygen demand and supply, it is put forward that the style, aerating for 2 hours and aeration-pausing for 2 hours, is a proper operation. Under the given condition of this operation style, the effect is superior to that of continuous aeration. It has better removal effect of Nitrogen and Phosphorus.Materials and energy balance in MIOD are studied to analyze its energy efficiency. Because mixing liquid and sludge circulate without pump, it saves these two circulations. The results show that MIOD is an energy saving process, saving 0.155 kw.h per m3 compared to the traditional activated sludge system. Under the condition of intermittent aeration operation, MIOD can save energy 48.4 per cent compared to continuous aeration. Through the analysis of energy flow, MIOD, as a whole, is of high efficiency. The main solution of saving energy for MIOD depends on the aeration equipment.