Nitrogen removal performance of ANAMMOX-PVA granules immobilized by different preparation methods

摘要

PVA (Polyvinyl Alcohol) was used to encapsulate ANAMMOX (ammonia oxidation bacteria) in order to decrease microbial loss in ANAMMOX and its related process for wastewater treatment. Different types of granules with ANAMMOX sludge immobilized in PVA gel of different mass concentrations 6%, 10%, 15%, and 20%, were prepared by cross-linking in calcium chloride solution and deep-freezing method with 10% PVA solution. The results of nitrogen removal experiments showed that 10% was the best concentration for ANAMMOX sludge to be immobilized in PVA gel when better nitrogen removal performance and longer life could be achieved; the granules prepared by chemical cross-linking method had better performance than those prepared by freezing cross-linking method. The granules prepared using the former method removed nitrite in a shorter time period (after 24 h), whereas those prepared using the latter method reacted in 7 days.