The system consisted of a collection basin and a batch treatment unit in which the pH value was elevated using lime milk and chromate decontamination was carried out using sodium dithionite. The solids were separated using a chamber filtering press. The disadvantages of this solution included high personnel costs and large amounts of hazardous waste in the form of unusable sludge.
This is why JUMO decided to acquire a vacuum distillation plant for the general sanitation of this area. In this process, the wastewater is firstly vaporized under negative pressure at approximately 85 degrees Celsius. Next, a vapor compressor compresses the water vapor to normal pressure (at approx. 120 degrees Celsius). The water vapor can then provide the surplus energy for the vaporization of the wastewater again. The distillate is returned to the production areas as industrial water of pure water quality.
The new solution also makes use of JUMO measurement technology. An important key parameter is the pH value. Cyclical temperature and pressure changes, and an operating temperature of 95 degrees Celsius at the pH installation measuring point, place particularly high demands on the pH electrode. That is why the high-quality JUMO tecLine HY with a zirconium dioxide diaphragm is used. The particular design on the inside as well as a special hightemperature and high-pressure gel electrolyte ensure that the measurements are reliable.
The JUMO tecLine pH electrode is operated using a new JUMO digiLine digital transmitter. It is screwed directly on the head of the electrode so that it digitizes the measured values close to the measuring point itself. The sensor and measuring head form a unit for as long as the pH electrode wearing part is in a functioning condition. If it reaches the end of its natural life the electronic head can continue to be used with a new electrode. Other measurands in this type of plant include pressure and temperature. This is where the resilient JUMO dTRANS p30 pressure transmitter and the JUMO Pt100 RTD temperature probe come into play.
The choice of a vacuum distillation unit has paid off for JUMO. It conserves around 95 percent of energy compared with atmospheric distillation. Since JUMO generates excess energy through solar power and its own cogeneration plants, the implemented water energy process also makes sense from an energy point of view. We were able to construct the new plant so that it was considerably more compact. Virtually no pollutants exist and only one IBC container to collect the condensate is included. Since the distillate is returned to the production areas as industrial water of
pure water quality, valuable resources are saved and our environment is protected.