Wastewaters containing phosphorus and nitric acid are produced during biological treatment processes. In this study, a material for treating such wastewaters was developed. Foamed glass was produced from waste glass and then heated with iron sulfate to prepare an adsorbent for phosphorus and carrier for reducing nitric acid. The adsorbent performance was evaluated in batch and continuous experiments. The saturated adsorption amount of phosphate was 6.23 mg/g for the product obtained from glass of size 3 to 12 mm; the amount adsorbed was relatively high, in spite of the large glass size. The denitrification by reduction of nitrate was around 25%.