Enhancing microalgae growth and landfill leachate treatment through ozonization

Phycoremediation of landfill leachate (LL) with microalgae is a promising approach but the performances are usually inhibited by complex macromolecular organics and high chromaticity of the LL. To realize high-efficiency LL remediation and microalgae biomass production, a technique integrating ozonization and microalgae bioremediation was proposed, in which the LL was first pretreated with ozone to degrade most macromolecular organics and reduce chromaticity. Then the oxidized LL was remediated with microalgae biofilm to reclaim nutrients and produce biomass. Results showed that chromaticity was sharply reduced from 1400 to 45 Pt-Co and macromolecular organics were significantly reduced from 93.3% in the untreated LL to 54.8% in the oxidized LL via ozonization under 45 mg O-3/L for 45 min. The oxidized LL effectively enhanced microalgae growth and nitrogen removal. Then a phosphorus-feeding strategy was adopted to obtain different nitrogen/phosphorus (N/P) molar ratio of 33:1, 16:1; 7:1 and 3:1 for further enhancement of microalgae growth and nitrogen removal. As results, the maximum biofilm density of 28.0 g/m(2) and the highest nitrogen removal efficiency of 81.6% under N/P molar ratio of 16:1 were achieved. (c) 2019 Elsevier Ltd. All rights reserved.