SEQUENCING BATCH AND FLOW THROUGH ACTIVATED SLUDGE SYSTEMS - A FAIR COMPARISON

摘要

While many benefits shave been claimed for the Sequencing Batch Reactor (SBR)rntechnology, one of the main advantages is that it can fit into awkward sites. Onernexcellent example is the proposal for the new Dublin Bay Ringsend plant put forwardrnby a consortium for achieving partial nitrification and denitrification. In evaluating thisrntechnology for this 1.8-m population equivalent plant, the available footprint made itrnimpossible to fit a conventional flow-through plant on the site. The selection of SBRrntechnology required a detailed analysis of the other advantages claimed for thisrnprocess. While there are many applications in which the SBR system is highly suited,rnmany of the benefits claimed seem to lack substance. This paper points out some of thernmost popular misconceptions and selective interpretation of data found in the literature.rnThe Biowin SBR simulator as well as the spreadsheet simulator developed by Barnardrn& Sears (1977) was used to show the nitrification and denitrification behavior of variousrnsystems. The SBR model of the Biowin simulator was tested and calibrated against fullscalernresults from the Brandon, Manitoba plant. This was compared with some fullscalernresults from the other processes. It was found that the SBR system respondedrnmuch like the step-feed process in terms of the response to a diurnal TKN loading whenrnusing the same volume of reactors and final clarifiers. With a large safety factor andrnthus a long SRT both processes had the ability to produce low overall total nitrogen inrnthe effluent. Process selection should thus focus on other issues such asrnconstructability, need for balancing the flows for downstream processes, pumpingrnrequirements and back up for computerized systems.