Automation is a central issue when it comes to wastewater treatment, especially in terms of control and monitoring, increasing capacity, improving effluent quality, and meeting environmental compliance standards. Sean Ottewell reports
According to consultants Helmut Kaiser, the world market for water and wastewater treatment is currently worth over US$500 billion (€384 billion). With control and compliance such important issues, investment in wastewater treatment technology always includes the latest in automation technology (Fig. 1).
Utilities Kingston (UK), owned by the City of Kingston, Ontario, is an international leader in the wastewater treatment field. The company has just completed a US$103 million (€79 million) expansion of the Ravensview wastewater treatment plant, located on the shores of the St. Lawrence River.
The company’s goals for the Ravensview plant were to increase effluent capacity; to improve effluent, air and water quality; to reduce noise; and to provide superior bio-solids handling, energy savings and efficiency.
To achieve this, UK chose a Rockwell Automation PlantPAx Process Automation System solution which included programmable automation controllers (PACs), intelligent motor control centres (MCCs) and variable frequency drives (VFDs), as well as field services including Protection Plus start-up services, factory acceptance testing and TechConnect phone and online support.
The Ravensview primary effluent pumps, centrifuges, sludge pumps, chain and flight sludge collectors, blowers, compactors and HVAC equipment are now controlled using Allen-Bradley MCCs and VFDs from Rockwell Automation. Allen-Bradley CENTERLINE 2100 MCCs with IntelliCENTER technology package Allen-Bradley soft starters to control process applications. IntelliCENTER software provides site operators remote access, real-time diagnostics such as incoming power, pump performance and efficiency and electronic MCC documentation. Access to this type of information helps UK minimise MCC downtime and improve equipment performance.
The Allen-Bradley SMC Flex solid-state motor control soft starter installed on the blowers provides intelligence, advanced protection, unmatched performance, diagnostics, and communication. It integrates a bypass to minimise heat generation during run time, which automatically closes when the motor reaches its nominal speed, resulting in a cooler running component and compact enclosure. Also integrated into the plant’s system are the Allen-Bradley PowerFlex 70 and 700 AC drives that provide improved process control. These PowerFlex drives provide additional process information from the drive level and automatically disperse it to any part of the plant through the architecture.
To measure and provide power-quality reports, UK installed an Allen-Bradley Powermonitor 3000 on each MCC, each service entrance and each generator. It performs real-time power monitoring, data and event logs, harmonics analysis, sag and surge detection and load factor calculation. The compact power quality and sub-metering monitor helps UK leverage the DeviceNet networks without the need for cumbersome serial interface bridges.
Integration was also key to the project’s success. According to Louis Fournier, assistant chief electrical engineer at JL Richards, the engineering company who worked with UK, project milestones missed due to unexpected technology integration and start-up issues can cause delays that are calculated at approximately US$80,000 (€62,000) per day.
The system integrator who assisted in start-up and commissioning of the complex network was trained on the PlantPAx Process Automation System. Using one plant-wide control system simplifies training, saves time and facilitates troubleshooting.
“The week that the integrator spent at Rockwell Automation would have easily taken four weeks on site,” says Fournier. “Trying to sort out communication issues on site typically slows down the process.”
UK, JL Richards and the system integrator attended the factory acceptance testing, which took less than two days. They reviewed the EtherNet/IP network redundancy and the communication of all the PACs and DeviceNet networks, including the operations of the valve actuators. The contractor and system integrator were able to focus on the installation and commissioning of the process rather than the communication of the networks, notes Fournier. [Page Break]
Wireless options
At a French treatment facility designed by Veolia Water Solutions, an innovative method has been implemented for a common wastewater treatment application involving sludge drying. The sludge drying process is a residual element of the application that takes place once water has been cleaned and decanted.
In the SOLIA solar sludge drying process developed by Veolia subsidiary MSE, sludge is treated by a centrifuge and laid out in windrows in a greenhouse heated by solar radiation. An automated robotic turner is used to aerate the sludge and accelerate water evaporation. The robots are radio-controlled, which provides a more robust solution than the traditional wired approach. With wireless control of the robots, the entire operation is automated, and there is no further need for operators to enter the greenhouse.
MSE has decided to attach radios to the robots to enable information to be sent back and forth with the control station. This means the operator can control the robot remotely, program its movements and know its current position. The robot has an onboard controller, which interfaces with the radio.
“Implementation proved to be very simple, thanks in particular to ProSoft Technology´s technical support,” explains Xavier Bousquet from Veolia Water Solutions and Technology. “As far as the choice of supplier was concerned, we stuck to the specifications given by RG2I, their local distributor. Our major concern was reliability. We had to have a reliable solution, with none of our users encountering any problems. This is indeed the case with ProSoft Technology´s RadioLinx solution.”
According to ProSoft Technology, its RadioLinx solution brings all the advantages of wireless connection to industrial automation applications, while still offering high levels of reliability. In addition to its ability to withstand harsh operating conditions, it also improves the transmission of Ethernet data packets. The standards set out in IEEE 802.11 (commonly known as Wi-Fi) bring an extremely high level of security (802.11i), flexibility and interoperability to industrial automation applications.
Originally designed for office and home applications, these less robust technologies have limitations when it comes to industrial protocol transfer, resulting in transmission problems for industrial automation systems associated with the radio transmission method used for Ethernet packets. But the RadioLinx range of industrial solutions ensures optimal transfer of data packets.
To improve data packet transfer, RadioLinx uses a specific signal processing algorithm implemented by ProSoft Technology. This allows better use of the full bandwidth and supports the fast data transmission speeds demanded by industrial automation engineers. This is particularly vital for industrial applications (involving protocols such as EtherNet/IP) with a need to transport non-critical messaging data but also critical industrial I/O data.
So far, ProSoft Technology radio systems have been installed at half a dozen of Veolia’s sites. [Page Break]
Rapid adaptation important
In the water and wastewater industry a fast reaction to current and specific requirements is important. System integrators must be able to adapt standard systems rapidly and without great effort to customer-specific requirements.
With its block library, Siemens offers an efficient engineering support tool for the SIMATIC PCS 7 process control system and the SIMATIC WinCC visualisation system. This ‘Industry Library’ is available as a PCS 7 add-on product for PCS 7 V8 onwards and WinCC V7.0 SP3.
Important features include multi control concept with integration of local panels, integration of SIMATIC S7-300 controllers into SIMATIC PCS 7 projects, and integration of package units - also based on SIMATIC S7-300.
Advantages for consultants and system integrators include considerable reduction of time and cost through failure reduction in engineering and commissioning by use of tested function blocks and standardised engineering tools.
According to Siemens, plant operators also reap benefits. For example, there is high security of supply and disposal through the intuitive and uniform operator guidance according to SIMATIC standards. Then there is reduction of operation costs through hardware and software standardisation, such as reduced overhead for familiarisation and training through consistent operator guidance in all operation levels. In addition, projects can be carried out swiftly because of the use of tested function blocks.
Wireless solution for critical data
Text: FreeWave Technologies, manufacturer of high-performance spread spectrum and licensed radios for critical data transmission, has announced that together with its technology solution partner Process Control Dynamics, it has installed wireless data radios for the communication network used by Parker Water and Sanitation District in Colorado, USA.
The radios provide real-time monitoring and transmission of critical data to help ensure high-quality, safe water for more than 17,000 single family equivalents (SFEs) deployed across 43 square miles of the Parker community.
Currently, Parker Water and Sanitation District uses FreeWave’s HTPlus, FGR Serial radios and FGR2-IO radios.
“FreeWave’s radios were easily integrated into our existing supervisory control and data acquisition (SCADA) network and can communicate with all of our programmable logic controllers (PLCs),” said Kirk Magnusson, systems administration manager at Parker Water and Sanitation District. “The result is one cohesive system that sends critical data in real-time. With the configuration and diagnostics tools that FreeWave offers, we also can manage the radios from our desktop. With our old system, if a radio had a communication issue, someone from the team would have to drive out and locally fix it. The advantages of selecting FreeWave radioshave resulted in exceptional reliability and performance, but we also have been especially impressed by FreeWave’s around-the-clock customer support.”
Today, the radios are used for monitoring critical data at its water and wastewater facilities, including tank levels, temperatures, pressures, and pump control.