Clean water supply and wastewater disposal systems are essential to public health. In the Brazilian federal state of Santa Catarina, the main water & wastewater plant operator is the semi-public company Casan: They supply 194 municipalities, treat over 260 million m³ of water per year, and thus serve 66% of the federal state’s population. ABB is an ideal partner for water & wastewater operators when it comes to reliable and cost-effective applications.
Securing the flow of water and wastewater
In order to handle this enormous volume and properly treat wastewater, Casan requires a complex control system which is able to monitor key process factors, such as water flow velocity and chemicals. For water & wastewater plant operators, flow velocity is a major concern: During pre-treatment, particles like rock and sand are removed from the wastewater. In order for these particles to settle on the ground of the basin and be removed, the water flow rate must not be higher than the particle settling rate.
It is really critical to get the speed right – otherwise, downstream pumps might be damaged, thus leading to interruptions in operation. ABB equips Casan not only with highly reliable, energy-efficient drives which move the water, but also with programmable logic controllers (PLCs) which precisely control the drives’ speed and energy consumption.
“We started working with ABB’s AC500 PLC last year and were positively surprised by how quickly and comfortably the drives could be programmed using the Drives Library with ready-made function blocks. We can now set the drives to precisely the right speed for optimum water flow rate while keeping energy consumption low. High compatibility and reliability were key factors for us when choosing ABB as our new automation technology supplier”, says Roberto Oenning, Control and Automation Engineer with CASAN.
Uninterrupted remote control for lower costs and higher quality
In addition to flow speed, the AC500 PLC can control further elements of the wastewater treatment plant such as the air blowers in the aeration basin or the dosing pumps which regulate the addition of disinfectants. For Casan, the PLC receives data from numerous sensors distributed throughout the plants, processes it and sends it to the SCADA system where operators can take action. The new PLCs were effortlessly integrated into Casan’s existing SCADA system which is not by ABB.
“Our water & wastewater treatment plants are distributed over an area of almost 15 000 km². We therefore regarded it as essential to be able to control our processes remotely. Our operators can now monitor the data collected by the PLCs and sent to the SCADA system from far away by simply looking at a tablet. We have 400 simultaneous access points for our staff so that all plants can be properly controlled. This saves us time and travel costs and is ultimately more sustainable”, adds Roberto.
Source © Casan Brazil 
Source © Casan Brazil 
Source © Casan Brazil 
PLC Automation product family
This way, Casan knows at all times about the levels of certain chemicals contained in a plant’s effluent, among them salts, metals, pesticides, pharmaceuticals, plastics and many more. Making this data available via a PLC and being able to react to it improves water quality and, with this, public health. “With ABB we have found a partner who provides a comprehensive and reliable solution for controlling our vast network of water & wastewater plants. This allows us to monitor water quality at all times and provide the best possible service to the 2.7 million people depending on us”, Roberto concludes.
More efficiency with easy integration into existing environment
ABB can both integrate automation technology such as PLCs and drives into existing, third-party solutions, as has been the case here, or provide a tailor-made comprehensive solution comprising the SCADA system ABB zenon, PLCs, Drives, HMIs, and more.
