NUK - logo
E-viri
Celotno besedilo
Recenzirano Odprti dostop
  • Recovery of ammonia from do...
    Sancho, I.; Licon, E.; Valderrama, C.; de Arespacochaga, N.; López-Palau, S.; Cortina, J.L.

    The Science of the total environment, 04/2017, Letnik: 584-585
    Journal Article, Publication

    The integration of up-concentration processes to increase the efficiency of primary sedimentation, as a solution to achieve energy neutral wastewater treatment plants, requires further post-treatment due to the missing ammonium removal stage. This study evaluated the use of zeolites as a post-treatment step, an alternative to the biological removal process. A natural granular clinoptilolite zeolite was evaluated as a sorbent media to remove low levels (up to 100mg-N/L) of ammonium from treated wastewater using batch and fixed bed columns. After being activated to the Na-form (Z-Na), the granular zeolite shown an ammonium exchange capacity of 29±0.8mgN-NH4+/g in single ammonium solutions and 23±0.8mgN-NH4+/g in treated wastewater simulating up-concentration effluent at pH=8. The equilibrium removal data were well described by the Langmuir isotherm. The ammonium adsorption into zeolites is a very fast process when compared with polymeric materials (zeolite particle diffusion coefficient around 3×10−12m2/s). Column experiments with solutions containing 100mgN-NH4+/L provide effective sorption and elution rates with concentration factors between 20 and 30 in consecutive operation cycles. The loaded zeolite was regenerated using 2g NaOH/L solution and the rich ammonium/ammonia concentrates 2–3g/L in NaOH 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%. Ammonia nitrate and di-ammonium phosphate concentrated solutions reached up to 2–5% wt. of N. Display omitted •A natural zeolite was evaluated to recover ammonium in column experiments.•Loaded zeolite was regenerated and rich concentrates were used in a LLMC system.•Hollow fibre liquid-liquid membrane contactors were used to produce liquid fertilizers.•The closed-loop configuration allowed recovery ratios of ammonia higher that 98%.•Concentrated solutions reached up to 2–5% wt. of N.