Recovery of ammonia from domestic wastewater effluents as liquid fertilizers by integration of natural zeolites and hollow fibre membrane contactors
The research presents a study on the use of zeolites, a type of mineral, as a post-treatment step for the removal of ammonium from treated wastewater. The researchers used a natural granular clinoptilolite zeolite to remove low levels of ammonium from treated wastewater. The zeolite was activated to the Na-form and showed an ammonium exchange capacity of 29 ± 0.8 mg N-NH4+/g in treated wastewater. The ammonium adsorption into zeolites is a very fast process when compared with polymeric materials. The loaded zeolite was regenerated using a 2 g NaOH/L solution and the rich ammonium/ammonia concentrates were used in a liquid-liquid membrane contactor system in a closed-loop configuration with nitric and phosphoric acid as stripping solutions. The ammonia recovery ratio exceeded 98%.
The study is significant as it presents a potential solution for the removal of ammonium from wastewater, which is a major environmental concern. The use of zeolites for this purpose is a novel approach and could contribute to ongoing discussions on wastewater treatment methods. The study also offers benefits to readers by providing a detailed methodology and results of the experiment, which could be useful for further research or practical applications.