The effect of initial loading on the removal of ammonium and potassium from source-separated human urine via clinoptilolite

Abstract

Collection of wastewater in segregated streams is one of the new concepts in domestic wastewater management. One such stream is yellow water which is mainly human urine. Direct use of this richest fraction in terms of nutrients on plants as fertilizer is one of the recommendations as the final end use. Indirect use of urine as fertilizer may also be exercised after various modes of processing. One of those is processing with clinoptilolite to transfer plant nutrients onto the zeolite and then to recover them subsequently. One of the significant factors in this process is the initial nutrient loading with which clinoptilolite is charged. This paper aims to investigate the transfer of ammonium and potassium from source-separated urine onto clinoptilolite, concentrating upon surface concentrations attained and removal efficiencies under various initial ammonium loadings. The results have indicated that variations in initial loading have no significant effect in terms of removal efficiencies up to 10 mg NH4+/g clinoptilolite. Highly acceptable efficiencies could be attained up to 15 mg NH4+/g clinoptilolite after which the efficiency goes down as initial loading is increased. Overall, increased initial loadings result in higher final surface concentrations but decreased removal efficiencies.