Feasibility of using a novel algal-bacterial biofilm reactor for efficient domestic wastewater treatment. Issue 4 (10th February 2020)

• Record Type: Journal Article
• Authors: Gou, Yao; Yang, Jixiang; Fang, Fang; Guo, Jinsong; Ma, Hua
• Is Part Of: Environmental technology. Volume 41:Issue 4(2020)
• Page Start: 400
• Page End: 410
• Publication Date: 2020-02-10
• Subjects: Algal-bacterial -- biofilm -- wastewater -- algae -- inorganic carbon; Environmental engineering -- Periodicals; Environmental protection -- Periodicals; 628.05
• DOI: 10.1080/09593330.2018.1499812
• Languages: English
• ISSNs: 0959-3330

Abstract

ABSTRACT: Current algal-bacterial consortia require high hydraulic retention times (HRTs, 2–10 days) to efficiently remove pollutants from domestic wastewaters. A novel algal-bacterial biofilm reactor was developed for a much lower HRT. The results showed that an HRT of 12 h ensured 90% removal of organic matter and ammonium, and phosphate removal was approximately 30%. Decreasing the HRT to 8 h significantly deteriorated the reactor's pollutant removal efficiencies and increasing the HRT to 24 h did not improve these efficiencies. Illumination, which was light source for algae, was provided by a LED light. Activity tests showed that organic matter and ammonium removal rates resulting from illumination were 70% and 50%, respectively, of the rates when dissolved oxygen concentration was maintained at 2 mg/L. Chemical oxygen demand (COD) removal rates resulted from illumination and aeration were 18.63 and 25.38 mg COD/L.h, respectively. The phosphate removal rate was 0.26 and 0.43 mg/L.h when illumination and aeration were applied, respectively. The ammonium removal rates were approximately 10, 390 and 5000 mg NH 4 + − N / m 2 . d when the reactor was aerated or illuminated, respectively. These two rates were significantly higher than reported nitrification rates. Moreover, the percentage of Oscillatoria sp. increased from below 10% to over 90% under the applied organic load and temperature, while the percentage of fast growing algae, Chlorella, chroococcus sp and Scenedesmus sp., decreased from over 90% to below 10%. These results showed that an algal-bacterial biofilm reactor with a low reactor footprint was developed. GRAPHICAL ABSTRACT: