Recovery of nutrients (N-P-K) from potassium-rich sludge anaerobic digestion side-streams by integration of a hybrid sorption-membrane ultrafiltration process: Use of powder reactive sorbents as nutrient carriers.

Here, an alternative nutrient (N-P-K) recovery route from potassium-rich sludge anaerobic digestion side-streams using powder reactive sorbents (PRSs) is presented. In the first step, the optimum PRS system was determined in batch experiments with mixtures of: a) a sodium zeolite (NaP1) to facilitate the NH and K sorption; b) a Ca-zeolite (CaP1) to facilitate the removal of P by formation of Ca-phosphates (e.g.