The mechanism of bio-regeneration process of natural zeolite

Pilot-scale zeolite bed was constructed to discuss the influence upon the regeneration efficiency of zeolite by aeration, heterotrophic bacteria and nitrifying bacteria. The regeneration efficiency of zeolite was enhanced by 0.5%~1.0%, 20.9%~31.1% and 120%~180% with the present of aeration, heterotrophic bacteria and nitrifying bacteria, respectively. Nitrifying bacteria played a major role in the regeneration process of ammonia-saturated zeolite, followed by heterotrophic bacteria and aeration. When heterotrophic bacteria and nitrifying bacteria coexisted in a reactor, a synergistic effect had been observed, which could not only improve the regeneration efficiency up to 100%, but also increase the regeneration rate about 10%. The influence of ion-exchange, aeration and heterotrophic bacteria alone or in combination on the regeneration efficiency of zeolite fitted the first order kinetic reaction. And the curves of regeneration efficiency with nitrifying bacteria was described by y=kx and the Monod equation(R20.99). Through investigation on the change of SEM on zeolite surface before and after zeolite biological regeneration, the mechanism of bio-regeneration process of ammonia-saturated zeolite was revealed.