WASTE WATER TREATMENT, MEDIA THEREFOR AND ITS MANUFACTURE

摘要

A loose particulate material for use in waste water treatment comprises granules of plastics material carrying weighting material so that the granules have an average density of approximately 1.0g/cc. At least a portion of the weighting material is carried within the granules and the surfaces of the granules are provided with concavities to provide a habitat for organisms effective in waste water treatment. The particles are manufactured by incorporating a weighting material into the granules, contacting the granules with grains of a soluble substance at an elevated temperature to coat the granules with the soluble substance grains and subsequently dissolving the soluble substance grains. The weighting material may be sand, the soluble substance may be sodium chloride.