Dealing with Industrial Waste

processed-galiguGalligu: The North-West of England has been left with significant contamination liabilities from historic chemical processes. One such example was the Le Blanc chemical process, which converted common salt into soda ash using sulphuric acid, limestone and coal. The most significant waste product from this process was the highly toxic, caustic Galligu, principally calcium sulphate, but containing numerous other heavy metals.

Large areas of Widnes, Runcorn, and St Helens are blighted by this waste, which places a significant constraint on potential redevelopment because of its unique physical properties. Depending on its state of oxidation and water content, Galligu when dry has a silty sand texture, but when wet the waste rapidly softens and becomes thixotropic. These properties lead to ground instability and as a result much of the area impacted by Galligu is left undeveloped. However, when this material was treated with the material may be chemically stabilized and strengthened, so that it can be used in any location on a development.

Following a typical treatment, independent testing has historically demonstrated: (1) Soaked CBR strengths ranged from 50-85%, (2) Permeability of the treated Galigu soil varied from 0.13 x 10-9 to 0.86 x 10-9, and (3) Leachate values for arsenic (<1µg/l), cadmium (<1µg/l), chromium (10µg/l), lead (<10µg/l), zinc (19 - 250µg/l), Copper (20 - 200µg/l), Selenium (<8µg/l) and Nickel (<30µg/l) --- All contaminant values were less than the maximum concentration values stipulated in the Water Supply (Water Quality) Regulations 1989 of England and Wales. Get in touch for more information