Start-up of demoplant for optimization of chemical precipitation
|Flocell AB - Flocell
|Funding from Vinnova
|SEK 300 000
|March 2017 - March 2018
Purpose and goal
Flocell has run a pilot-plant for in situ polymerization of aluminum-based coagulants at Karlskrona waterworks. The raw water is taken from Lyckebyån - one of Sweden´s most contaminated and hard-treated surface waters. The test run has given continuous data through on-line analyses of turbidity and colour in raw and trested water. The data show that Al-dose and basicity must be dynamically regulated to achieve optimal purification results and lowest operating costs. The data also forms the basis for the development of an adaptive control system.
Expected results and effects
The project has verified that dynamic control of both Al dose and basicity results in better purification results and lower operating costs. Dynamic control is possible by adjusting basicity in situ. Two controllable parameters are obtained instead of conventional control where only the Al dose is regulated. The process control developed during the project includes e.g. an adaptive system where the critical contamination parameters, flow, temperature and pH of the work are measured online and stored.
Planned approach and implementation
Flocell used, in the tests. a container-based facility for in situ polymerization of Al-coagulant For the experiments, Karlskrona waterworks were chosen, where the raw water source (Lyckebyån) is one of Sweden´s most contaminated surface waters. On-line measurement of turbidity and absorbance at 254 nanometres in raw and treated water was used for data logging and control of Al dose and basicity. Measurements as the basis for the development of an adaptive control system. Al-sulfate and AlCl3 have been combined with Ca-Mg hydroxide during polymerization.