DEVELOPMENT OF SEWAGE SLUDGE SETTLEMENT TANK AUTOMATIC DISCHARGE SYSTEMS.

First steps were made towards automation by using the operator experience - on larger sites multiple tanks were monitored using closed circuit TV systems. Various sensor techniques were tested for measurement of sludge density, to replace the operator in the automation loop. The ultrasonic equipment developed was applied to the pipework of the sludge discharge line, since this allowed the simplest installation on tanks with rotating bridges or moving scrapers. Using Mobrey sensors for the signalling of light sludge is just an input to a control system for the sludge discharge. With microprocessors now involved in most instrumentation, the sludge discharge control system could obviously benefit from the sensible application of this technology.