Dilatometric measurement of bound water in wastewater sludge

The dilatometric technique is used to measure bound water in aerobically digested sludge. It is found that air liberated from the sludge sample during the freezing of the sludge water affects the quantity of unfrozen water (interpreted as bound water) determined by dilatometry. Both the freezing temperature and the solids concentration affect the measured bound water content. It is also found that the precision of dilatometry decreases with decreasing solids concentration and that the accuracy of dilatometry cannot be determined since there is no independent measure of unfrozen water.