应用在线传感器实现前置反硝化工艺生物脱氮的过程控制

为了实现前置反硝化工艺硝化反硝化反应的过程控制,系统地研究了硝化反硝化过程中DO、pH和ORP的变化规律,并考察了它们作为硝化反硝化过程控制参数的可行性.结果表明,pH值在缺氧区的变化分为下降型和上升型,从而指示系统反硝化反应进行的程度以及内循环回流量是否充足;缺氧区末端ORP值和硝酸氮浓度具有较好的相关性;好氧区第1格室的DO浓度可以指示进水氨氮负荷高低;pH值在好氧区的变化也可分为下降型和上升型,可指示系统硝化反应进行的程度、曝气量和碱度是否充足;好氧区末端ORP值与出水氨氮、硝酸氮浓度具有很好的相关性.在此基础上建立了硝化反硝化反应在线控制系统,从而实现曝气量、内循环回流量和外碳源投加量的在线控制,提高系统出水水质、降低运行费用.图7表1参8

Pre-denitrification Process Control of Nitrogen Removal Using On-line Sensors

In order to control pre-denitrification process, variation rules of DO, ORP and pH in the process of nitrification and denitrification were systematically studied. Feasibility of controlling nitrification and denitrification in pre-denitrified plants using DO, pH and ORP sensors was also investigated. Results showed that the variation of pH in anoxic zones could be classified into "descending type" and "rising type", which indicated if the denitrification extent and nitrate recirculation flow were sufficient. The ORP value and nitrate concentration at the end of anoxic zone also had good correlation. The DO concentration in the first aerobic zone could indicate the influent ammonia load. The variation of pH in aerobic zones could also be classified into "descending type" and "rising type", well indicating the extent of nitrification, aeration and alkalinity were sufficient. The experimental results also showed a good correlation of ORP values in the last aerobic zone with effluent ammonia and nitrate concentrations. An on-line system to make an integrated use of these signals for on-line control of aeration, nitrate recirculation flow and external carbon dosage was presented and demonstrated with promising results. Fig 7, Tab 1, Ref 8