Control system of disposal facility used for neutralization of alkali-acid, chromium and cyanide waste-water

MEP Postrelmov, a.s. is one of the oldest plants with electro technical production in North Moravia. In 1931 the company began production of low voltage devices, starting circuit-breakers, resistors and signal lightings for airports and railways. During World War II it produced low voltage devices for the German army. In 1948, three years after World War II, the MEP Company was nationalized and joined to the MEZ Postrelmov national enterprise.

Today, MEP Postrelmov produces electric devices and electric switchboards which are used in electric transportation, power supply, and in engineering. In addition, the company produces parts and kits for devices used in the engineering industry and cast products from aluminum. MEP Postrelmov also provides surface finishing of metals.

Control system

The company has its own electrotype department with disposal facility where chemicals from galvanization are neutralized. In 2007, the management of the MEP Postrelmov company decided to install a new control system of disposal facility used for neutralization of alkali-acid, chromium and cyanide waste-water. The main reasons for implementation of the new control system were the optimization of the production processes and minimization of human errors. Complete reconstruction, including the implementation of the new SCADA-based control system, was provided by AITEC s.r.o. Thanks to installation of the new control system, the disposal facility provides 24 hour operation and its output has been increased to 16m³ per hour.

All the pipelines were equipped with servo-operated valves. Reaction and sedimentation tanks were equipped with the system providing continuous measurement of the tank levels. The disposal facility was also equipped with the system used for automatic dosing of the chemicals. Brand new devices for automatic measurement of the pH and redox were installed in the chemical reactors as well. Thanks to the installation of the new pH Adjustment System and ion exchanger it was possible to increase the flow performance of the entire disposal facility.

The SCADA-based control system consists of one distribution box which is fitted with a Tecomat TC 700 PLC device. Communication is provided over the RS232 bus and over the Ethernet. The new control system also enables control of all systems and cleaning procedures of the disposal facility.

Control of the disposal facility is provided by the Reliance SCADA/HMI system. The visualization windows run on two computers – on the operator panel in the neutralization station and on the computer in the technicians lab. The operator panel provides display and control of neutralization station systems and displays important data from the cleaning processes.

The visualization on the second computer (in the lab) only provides supervision of the cleaning processes. This computer communicates with and obtains data from the operator panel over the local network (LAN).The control system also provides log and archive changes of the cleaning process to the database. This is a very good feature for further analysis or supervision.

By implementation of the new SCADA-based control system with Reliance facilitates better quality of processed water flowing to the sewer system. According the BAT and BREF guidelines the disposal facility meets the requirements for the current technology.

Examples of visualization windows

Visualization of the electrotype department - picture 1

Visualization of the electrotype department - picture 2

Visualization of the electrotype department - picture 3

Visualization of the electrotype department - picture 4