Stabilisation of concrete wash water
NOTE: The discussion below describes one application of the DELVO System: overnight / weekend stabilisation of concrete wash water. Additional applications of the DELVO System are outlined in the DELVO System Information Sheet.
Overview
At the end of each day, when a 7.0 cubic metre ready-mix truck returns to the plant with no leftover concrete, that truck will contain approximately 350 kg of cement, fine aggregate and coarse aggregate adhering to the inside of the truck drum. It is a common practice in the ready-mixed concrete industry to wash this residue out using approximately 600 to 2000 litres of water to thoroughly clean the inside of the drum. Conventional methods for the disposal of concrete wash water include dumping:
- At the jobsite
- At a landfill
- Into a reclaimer / recycler unit
- Into a concrete wash water pit
- In the ready-mix plant yard
The removal of hardened residual wash-out can result in expensive labour costs, excessive wear and tear on front-end loaders, and costly hauling charges. Some environmental protection agencies consider concrete wash water to be a hazardous material and regulate its disposal. Ready-mix producers could easily comply with these regulations if they had a cost-effective solution to the problem.