Servicio de Información Comunitario sobre Investigación y Desarrollo - CORDIS

Experimental tests of the piwamas prototype

Further optimisation is still needed regarding the flow in the lamella separator. The simulation has shown that the velocity in the second chamber is only routed to another direction but an equal distribution of the flow could not be reached.

The angle of the lamella has not been changed as we had the highest angle. If the angle would be smaller, the slipping of the particles, settled down on the lamellas, could be prevented. For the further optimisation of the separator, different lamella types and the modification of the distance between the lamellas could be performed. Due to time limitations, this could not be done during the project.

The activated carbon prototype was built to test the efficiency of absorption of TBT, PCB and heavy metals from shipyard wastewater. The prototype consisted of three columns, two of which were packed with KAC in different configurations (1 rolled KAC, 1 stacked KAC). The third column was packed with GAC. Wastewater was pumped through the 3 columns at similar flow rates. Outlet samples were collected for analysis and results were compared.

The GAC column and the stacked KAC configuration gave the most favourable results under real conditions at the shipyard. Some problems were experienced with the stacked KAC configuration: the wastewater did not flow through through the KAC layers with ease, a fact supported by the high back pressure observed at the base of this column. Some design changes, which improved performance for a short period, were made

The Reverse Osmosis was supplied to remove the salt concentrations of the waste water that will be re-utilized in cleaning operations of the shipyards. Samples were collected in the inlet and outlet water in order to determine the efficiency of the system. The outlet streams from the three separate AC columns were combined to form one single wastewater stream, which was pumped to the desalination system. The pump (P6) feeding the desalination system requires continuous operation, while the pumps (P3, P4, P5) feeding the activated carbon columns operates on a discontinuous basis. Therefore, the flow-rate to the desalination unit was not as effective as had been hoped. In addition, the hydraulic pressure is higher than 0.5 bar and the system is now mere operation to protect the reverse osmosis membranes rejecting water directly through a bypass system.

Regarding the wastewater quality a continuous monitoring at the outlet of each individual treatment step must be installed. A PLC (SIMATIC S7-300) was used to program the control system. With appropriate sensors such as conductivity, pH value and turbidity the individual treatment steps (lamella separator, activated carbon unit and desalination) are switched on or off in dependence of the measured degree of water quality. The treated water from a certain treatment step is recycled via a valve into a storage basin if a parameter is above a certain limit value. If the water quality at the end of a treatment step requires further treatment, the next treatment unit is activated and the water treatment is hence improved.

For the process control and visualization application the WinCC (Windows Control Centre) system software was used. WinCC is a Human Machine Interface means controlling the process, keeping machines and plant operating on standard PCs running Windows NT and Windows 2000. It enables individually configured user interfaces to be created for every application - for more reliable process control and optimisation of production in general.

Reported by

An der Karlstadt 10
See on map
Síganos en: RSS Facebook Twitter YouTube Gestionado por la Oficina de Publicaciones de la UE Arriba