Abstract
Two selected waste building sludges (WBS) were used in this study: (i) sludge from the production and processing of prestressed concrete pillars (B) and (ii) sludge from the production of technical stone (TS). The materials were used in their original and Fe-modified forms (B(Fe)/TS(Fe)) for the adsorption of NH(4)(+) and PO(4)(3-) from contaminated waters. The experiments were performed on a model solution simulating real wastewater with a concentration of 1.7 mmol·L(-1) (NH(4)(+)) and 0.2 mmol·L(-1) (PO(4)(3-)). The adsorption of PO(4)(3-) had a high efficiency (>99%) on B, B(Fe) and TS(Fe), while for TS, the adsorption of PO(4)(3-) was futile due to the high content of available P in the raw TS. The adsorption of NH(4)(+) on all sorbents (B/B(Fe), TS/TS(Fe)) had a lower efficiency (<60%), while TS proved to be the most effective. Leaching tests were performed according to the CSN EN 12457 standard for B/B(Fe) and TS/TS(Fe) before and after NH(4)(+) and PO(4)(3-) sorption when the contents of these ions in the leachates were affected by adsorption experiments in the cases of B and TS. For B(Fe) and TS(Fe), the ion content in the leachates before and after the adsorption experiments was similar.