Research projects
Research area D: Process chain
Research area D is at the center of WERA and interacts with the other research areas. Research area D investigates the influences on P recovery in a real, dynamic system (project D1). To this end, the adsorber materials synthesized in research area A are tested for their suitability for selective P separation and enrichment in increasingly complex, different wastewater matrices. The basic principles of precipitation and crystallization developed in research area B will be incorporated into the design of processes and experiments for P recovery from sewage sludge. The measurement techniques and separation methods developed in research areas B and C will be tested on real wastewater systems. Based on the results of the experiments, process chains are developed in research area D. The results of the experiments will be used to calibrate and verify the simulation results in research area B. In research area D, the adsorber materials developed in research area A are agglomerated into larger porous particles and the mechanical stability of the adsorber particles within the process chain is investigated (project D2).
Supervisor: Prof. Heidrun Steinmetz
The effort for phosphorus (P) recovery from sewage sludge is high, because phosphorus is transferred within the wastewater treatment into the sewage sludge mostly by precipitation with iron or aluminum salts to protect the receiving water and needs to be recovered subsequently from the sewage sludge in a multi-stage process. This process starts with the dissolution of phosphorus bound in the sewage sludge, subsequent complexation or precipitation of interfering ions like iron and renewed precipitation and crystallisation of the phosphorus in form of plant-available fertilizer.
Influences on these phosphorus precipitation and recovery steps are manifold. Technologies used for P-elimination as well as the type and composition of the sewage sludge have a significant influence on the P-recovery steps. The precipitation and crystallisation of struvite as a possible product of P-recovery depends on numerous factors, such as the pH value of the solution, the saturation, the molar ratios of various ions, the stirring speed, the temperature and the presence of foreign ions. Yet these influences are not clearly understood.