Concrete washout: the silent polluter...

For years, the construction sector has claimed to take a responsible approach to its activities, placing strong emphasis on environmental best practice. In most respects, this approach has been widely adapted, for which the construction sector should be applauded. There is, however, one area where best practice is frequently overlooked; concrete washout and the resulting high pH water. As Dr Richard Coulton, managing director of Siltbuster notes, it is a critical issue and one that the industry is, in the main, still ignoring...

“The pH of concrete washwater is incredibly high - typically 12 to 13 on a scale which runs from 1 (acid) to 14 (highly alkaline). Only domestic oven cleaner has a higher pH and think of the health warnings that come with that. Yet, across the country, the sight of skips lined with plastic liners and full of concrete is a common occurrence. This is a limp attempt to deal with ‘waste’ concrete and leaves the high pH washwater free to seep into the ground water or run off into surface water courses.

“The Environment Agency (EA) officiates regulation in this area and, like all other forms of waterborne pollution, legislation is in place to penalise the organisation responsible. Even the EA itself has fallen foul of the legislation, with a case brought against them by an angry group of fishermen. Furthermore, high pH water is extremely corrosive potentially inflicting second degree burns.

“It is therefore imperative that the construction industry understands its obligations from an environmental legislation perspective and what this means in the context of dealing with alkaline and acidic waste water.

“Current processes for disposing of waste water are not best practice. High pH water from concrete washout is the silent polluter. It is vital to address the lack of awareness surrounding the issue if we, as an industry, are to further strengthen our environmental track record. We wouldn’t dream of pouring oven cleaner into our local rivers – and we should have the same level of consideration for dealing with high pH water.”