The main objective of this work consisted on programming PLCs (Programmable Logic Controllers) for monitoring and continuous control of Residual Water Treatment Stations. This work has been made in cooperation with a Technological Centre (“IDIT – Instituto de Desenvolvimento e Inovação Tecnológica”), having as final addressee the company “Extraresi – Criar Ambientes Limpos”, supplier of Residual Water Treatment Stations (RWTS). The research team has automatized units for different industrial sectors, as biodiesel refineries, enterprises of drying of cod, of cattle breeding and also for sanitary embankments and domestic water treatments. At last, the research team has developed a flexible programme that can be applied in any other RWTS supplied by the company Extraresi. The automatization of each station is based on a continuous monitoring of minimum and maximum levels of water in different phases of the treatment process, through the digital inputs of the PLC, and of the values of several physical-chemistry parameters, as pH and salinity, through analogical inputs. In function of the read values, the digital outputs of the PLC are actualized and determine the driving action of engines, valves and signals of alarm.
The research team also contributed for the project of the RWTS electric boards.
The Research Unit intends to continue to carry through this work of automation and to make other studies related with the Residual Water Treatment Stations, such as studies of use of alternative energies, in the direction to become them energetically autonomous, studies of remote monitoring of the process by GSM or Access Point and studies of optimization of the biological process of water treatment.
Carlos Alberto Rego de Oliveira
Pedro Miguel Pinto Reis Gomes