Profibus-enabled actuators support advanced water treatment plants

Jon Lawson

Profibus is a standardised open digital communication system for process automation that has been widely adopted for the automation of water and waste treatment plants around the world. Profibus DP is used to operate actuators and sensors via a centralised controller in these automated applications.

Conforming to the international open standard IEC61158/EN50170, the Rotork Profibus DP module is fitted inside the actuator electrical housing and interfaces directly with the actuator electronics. Once fitted, all the normal commands associated with moving the actuator, together with feedback and historical data, are available on the Profibus DP RS-485 highway. Up to 126 field units can be connected on a single two-wire communication network, provided suitable repeaters are included.

When installed in Rotork non-intrusive IQ intelligent electric valve actuators, in addition to providing full digital and analogue control, the Rotork Profibus DP interface card delivers comprehensive control and feedback data about the valve and actuator using DP-VO cyclic communication. Extensive actuator diagnostics and configuration information is included in the DP-V1 acyclic data supported by the card, enabling valve profiling and diagnostic data collected by the IQ actuator to minimise maintenance and be incorporated in asset management systems.

These benefits, combined with the company’s reputation for all-weather reliability and the local availability of technical support, make important contributions to the utilisation of IQ Profibus actuation technology in the global water and wastewater treatment industries, as illustrated by two recent examples.

Water case study

The upgrade and expansion of the Rio Manso Water Treatment Plant at Brumadinho in the south east of Brazil involves the building of additional filter plant, the replacement of obsolete actuators on existing plant and the introduction of a Profibus digital control network.

The majority of the 136 Profibus DP enabled Rotork non-intrusive IQ intelligent electric valve actuators involved are being installed to control the inlet, outlet and backwashing functions on the new and existing filters. The remainder of the actuators are installed on the sludge collectors, sludge thickeners and secondary collectors from which the raw water is extracted for treatment.

The upgrade is the first P3 (public private partnership) project to be performed by COPASA, a Brazilian company specialising in the design and implementation of solutions for water supply, sewage and solid waste management.

Wastewater application

The Viseu Sul WWTP in Portugal’s Viseu County is the first in the country to adopt advanced membrane filtration (MBR) wastewater treatment technology. The highly automated treatment facility, serving a population of 90,000, was inaugurated by the President of Portugal, Marcelo Rebelo de Sousa, and is named as a national environmental benchmark for future developments.

MBR treatment plants work without the addition of chemicals and with relatively low energy consumption, combining secondary and tertiary treatment and eliminating traditional sand and carbon filtration. Centralised process control and automation at Viseu Sul is facilitated using Profibus DP network technology, using Rotork’s latest multi-turn and part-turn non-intrusive IQ intelligent electric actuators (IQ and IQT respectively) to operate penstocks and butterfly valves for flow control throughout the wastewater treatment process.

In addition to being the most advanced WWTP in Portugal, the new Viseu Sul plant will enable the closure of other treatment plants in the area that do not meet the latest environmental regulations.

Sarah Kellett is with Rotork

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