Exploring the role of hydrogen peroxide in the microwave advanced oxidation process: solubilization of ammonia and phosphates. Issue 6 (1st November 2006)

• Record Type: Journal Article
• Authors: Wong, W T; Chan, W I; Liao, P H; Lo, K V; Mavinic, D S
• Is Part Of: Journal of environmental engineering and science. Volume 5:Issue 6(2006)
• Page Start: 459
• Page End: 465
• Publication Date: 2006-11-01
• Subjects: environment; Environmental engineering -- Periodicals; Sanitary engineering -- Periodicals; Environmental engineering -- Canada -- Periodicals; Environnement, Technique de l' -- Périodiques; Technique sanitaire -- Périodiques; Environnement, Technique de l' -- Canada -- Périodiques; Environmental engineering; Sanitary engineering; Canada; Electronic journals; Computer network resources; Periodicals; 628.05
• DOI: 10.1139/s06-020
• Languages: English
• ISSNs: 1496-2551

Abstract

Abstract : The focus of this study was to investigate the combined effects of hydrogen peroxide concentration and acid hydrolysis on ammonia and ortho-phosphate solubilization for subsequent struvite formation. A lower microwave temperature regime between 60 and 120 °C was of interest in this study because of the greater amount of polyphosphates found in the treated secondary sludge at these temperatures. At microwave-heating temperatures of 100 °C and 120 °C, it was found that increasing the hydrogen peroxide concentration resulted in an increased phosphorus and ammonia solubilization. At a reaction time of only 5 min, the combination of hydrogen peroxide and acid hydrolysis resulted in up to 61% of total phosphorus and 36% of TKN released into solution, as soluble ortho-phosphate and ammonia, respectively. The amount of soluble nitrogen in solution after microwave treatment was found to increase with the hydrogen peroxide concentration. Up to 39% of the total soluble nitrogen could be released into solution. Furthermore, the addition of hydrogen peroxide resulted in a dramatic decrease in the PO4 :NH3 molar ratio, an important factor controlling struvite formation. In terms of facilitating poly-P breakdown into ortho-phosphate in the acid hydrolysis process, hydrogen peroxide was found to be the most effective at 80 °C and at a concentration of 1.5 wt% H2 O2 . At temperatures of 100 and 120 °C, the amount of soluble ortho-phosphate increased with the hydrogen peroxide concentration. Key words : advanced oxidation process, ammonia nitrogen, hydrogen peroxide, microwave, phosphorus release, sludge, struvite.