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Focus Water & waste treatment Global water solutions

The expertise and support of Festo project engineers, plus the efficiency of Festo products and equipment, have proved invaluable in two water treatment applications - one in St. Petersburg, Russia, and the other in León, Mexico


aint Petersburg, the most northerly city in the world with a popula- tion of a million or more has resolved to implement a pro- gramme to increase the energy effi- ciency of the drinking water supply for its southern areas. For this purpose, the city has invested 2.6 billion roubles (around €65 million) over a period of three years. In addition to the moderni- sation of 34 pumping stations, Vodokanal, the St. Petersburg water utility company, has set itself the target of reducing the electricity consumption of the drinking water supply system by more than a third. Pneumatic automa- tion technology from Festo is helping by providing energy efficient solutions for the new treatment plants. Until now, electric drives were the first choice for Russia's water treatment plants – for opening and closing the inlets and outlets of sand-bed filters or in pumping stations. In St. Petersburg, the use of only electric drives would have meant an installed load of 75 kW. The plant could not have provided this without extending the electrical infra- structure. “In order to achieve the energy-saving targets which we had set ourselves, we therefore needed to find new solutions,” explained Maksim Pirschin, manager of the plant's block K-6 at Vodokanal. Vodokanal engineers sought an alter- native solution, and chose a pneumatic system with actuators DAPS, including two air compressors, which required an installed load of only 10 kW. “Simply by replacing the electric drives with 120 pneumatic actuators, we were able to save at least an additional €65,000,” said Pirschin.

The new block K-6 of the Surface

Water Treatment Plant South in St. Petersburg includes 20 new sand-bed filters. Each filter basin is assigned six butterfly valves with actuators and shut-off valves to open and close the inlets and outlets.

In addition to valve assemblies con- sisting of butterfly valves with actua- tors, shut-off valves and sensor boxes, which Festo supplied in ready-to- install form, Vodokanal has chosen ready-to-install control cabinets with VTSA valve terminals, pressure and flow sensors and service units from Festo's MS series. “If we source all the pneumatic automation equipment which we need from the same supplier,


we simply have fewer problems during operation and maintenance,” said Pirschin, “because Festo's experts are always there when we need them.” Block K-6 is equipped with a central control system at the process manage- ment level which allows monitoring of the water treatment process. The con- trol system gathers current data and compares this continuously with defined setpoints. The Festo automa- tion technology is fully integrated into this monitoring process and uses sensor signals to supply up-to-date informa- tion on the operating status of individ- ual plant sections.

In another international application, this time for the treatment of tannery wastewater in León, Mexico, Festo pro- ject engineers have ensured the effi- ciency and reliability of the plant, which operates over several levels of the automation pyramid.

Léon, an industrial city 400km north of Mexico City, is considered to be the world capital of leather and shoes. Brands such as Adidas, Nike and Caterpillar have their products made in 600 tanneries and 1,000 shoe and leather factories, generating tons of wastewater. Tannery wastewater requires special treatment: beside organic tanning agents, the wastewater from the factories may also contain salts and metals such as chrome, zirco- nium, aluminium, titanium and iron, together with synthetic tanning agents such as formaldehyde and phenols. The wastewater treatment plant, which was built by Fypasa in 2009, supplements a treatment plant for household wastewater. The latter was previously also used for tannery waste- water but in the long term proved insuf- ficient for the needs of the developing industrial city. Fypasa has been build- ing and operating wastewater treatment plants throughout Mexico since 1969 and treats 40% of all the wastewater in Mexico. “But as we are not specialists in plant automation, we rely on the experience of Festo's project engi- neers,” explained Mauricio Plascencia, operations manager of the Fypasa treat- ment plant in León.

Festo developed a complete solution covering everything from the sensor/actuator level through to the field level, the individual control level and the process control level, including a SCADA process visualization system.

Festo has been able to supply efficiency and relia- bility over several levels of the automation plat- form for plants treating tannery wastewater in León

“Starting with the engineering phase, we supplied Fypasa with a suitable automation concept, including circuit diagrams, CAD data and 3D models of the process valves and control cabinets, the central components of the sensor/actuator and field levels, so that they could be included in the designs as ready-to-install units,” said Eduardo Poupard, project engineer with Festo Mexico.

The purchasing phase was com- pleted efficiently thanks to the project management provided by Festo engi- neers, and the installation phase was simplified with simulation tests of the process valves and the control cabinets in the Festo Test Centre, the product documentation which Festo supplied and the installation of subsystems throughout the plant. During the com- missioning phase, the Festo project engineers conducted process tests for each unit within the plant.

At the individual control and process control level, the master controller PLC CECX-X-C1 from Festo feeds data to the SCADA software VipWin to allow process visualization. CPX/MPA valve terminals gather the input and output signals, feed these to the master PLC and activate the pneumatic actuators. These are installed in seven control cabinets for protection. The automation platform CPX also provides functions for remote maintenance, remote diag- nostics, a web server, text messages and an e-mail alarm.

The two fermentation towers are equipped with two types of process valves: gate valves for the sludge inlet and butterfly valves for the fermenta- tion gas discharge.

This holistic system approach, including process visualization, offers the plant operator greater transparency and thus more simplicity in the operat- ing phase. This means the system is easier to maintain, saves costs and increases efficiency as staff require little training to work with the pneu- matic system.

Festo T: 01604 667000

Enter 223 NOVEMBER 2013 Process & Control

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