Treatment of rainwater runoff in recovery and recycling companies: Lab and pilot-scale testing

Abstract

Wastewater released from the storage and/or processing of recycling and materials recovery can be characterised as rainwater runoff. Recuperation and recycling companies are confronted with wastewater that has a very fluctuating flow rate and composition. The flow rate mainly depends on the amount of rainfall while the composition additionally depends on what is currently stored on site. An analysis of possible physical-chemical treatment (coagulation/flocculation, sand filtration, activated carbon filtration and sedimentation) methods was performed at two different recycling companies in order to find a robust and economical feasible water treatment system that meets the discharge limits at all times. A violation of some measurement values (Cd, Cr, Ni and acenaphthene) after coagulation/flocculation occurred, which could be further reduced by using sand filtration. Good removal is achieved for common parameters as for mono- and poly-aromatic hydrocarbons (MAH and PAH) and polychlorinated biphenyls (PCB). Applying a coupled sand- and activated carbon filtration on runoff resulted in a removal of over 80% of several measurement values (suspended solids, heavy metals). This clearly indicates the applicability of the physical-chemical treatment techniques.

Keywords:

• Pilot installations
• (waste-) water treatment
• water reuse
• rainwater
• waste recycling
• sand filtration
• activated carbon filtration
• coagulation/flocculation

Acknowledgments

The authors wish to thank the European Regional Development Fund (ERDF) for the financial support within the ERDF Cleantech program (Mobile pilot installations for water treatment, project number 463). The collaboration with Boudewijn Meesschaert and Dominique Huits within this ERDF framework is greatly appreciated.

This project fits within the IWT-Tetra project REWARE (120118) and the LED H₂O project. The LED H₂O belongs to the LED network (www.lednetwerk.be) and is financially supported by The Flanders Knowledge Centre Water (Vlakwa vzw). The authors would also like to thanks the companies for the assistance with the experiments.