Process measuring and control systems in sewage treatment plants

Sewage treatment plants are dealt with presenting two papers which discuss process measuring and control concepts for sewage and sewage sludge treatment, biogas utilization and energy management. Models which provide the basis of the management of sewage treatment plants in the future are discussed as one of the points of main effort of the current development activities. Problem solutions remain to be found for process models which are prerequisite for control engineering applied on a larger scale. Experiences gained in the operation of a sewage treatment plant wich a very sophisticated process measuring and control system are discussed. On-line measuring techniques are dealt wich placing emphasis on the parameters BOD, COD, nitrogen, phosphorus, throughput and solid matter content. A survey of the present state of on-line measurements is followed by details about different available measuring techniques and about experiences gained in their application. (orig.)