| Abstract: | In previous reports from this laboratory it has been shown that the extended aeration process for biological treatment of organically laden municipal and/or industrial waste could be successfully employed for concurrent purification and sludge disposal. Also results using a modified process in which autodigestion was aided and controlled by periodic partial hydrolysis of small portions of the recycle sludge showed that operational control was feasible. There was some question regarding the success of such a process if the original waste contained a large portion of inorganic solids. Accordingly, a 1½ year pilot plant study was made using a waste (hydrolyzed trickling filter sludge) of exceptionally high ash content (50–60%). It was found that the ash content of activated sludge grown on this substrate did not continually increase nor did the high ash content of the waste interfere in any way with the efficiency of removal of organic matter. In general it exceeded 90 percent. Also a highly nitrified effluent was produced. A variety of analyses were performed: COD, BOD, TOC, suspended solids, NH3-N, organic-N, NO3-N, etc. Interrelationships between these important monitoring parameters for assessing plant performance offered useful insight into operational control for hydrolytically assisted extended aeration processes. |
