Coagulation/flocculation-based removal of algal–bacterial biomass from piggery wastewater treatment

• Published in: Bioresource technology 2011, Vol.102 (2), p.923-927
• Main Authors: de Godos, Ignacio, Guzman, Héctor O., Soto, Roberto, García-Encina, Pedro A., Becares, Eloy, Muñoz, Raúl, Vargas, Virginia A.
• Format: Article
• Language: English
• Subjects: Animal Husbandry; Animal productions; Animals; Applied sciences; Bacteria; Bacteria - isolation & purification; Biodegradation, Environmental; Biological and medical sciences; Biomass; Bioreactors - microbiology; Chitosan; Chlorella; Chlorella - isolation & purification; Chlorella sorokiniana; Chlorococcum; Coagulation; Exact sciences and technology; Flocculating; Flocculation; Fundamental and applied biological sciences. Psychology; Harvesting; Microalgae; Oxygenated; Piggery wastewater; Pollution; Scenedesmus - isolation & purification; Scenedesmus obliquus; Sus scrofa; Symbiosis; Terrestrial animal productions; Vertebrates; Waste Disposal, Fluid - methods; Waste water; Wastewaters; Water Purification - methods; Water treatment and pollution
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2010.09.036

Two conventional chemical coagulants (FeCl 3 and Fe 2(SO 4) 3) and five commercial polymeric flocculants (Drewfloc 447, Flocudex CS/5000, Flocusol CM/78, Chemifloc CV/300 and Chitosan) were comparatively evaluated for their ability to remove algal–bacterial biomass from the effluent of a photosynthetically oxygenated piggery wastewater biodegradation process. Chlorella sorokiniana, Scenedesmus obliquus, Chlorococcum sp. and a wild type Chlorella, in symbiosis with a bacterial consortium, were used as model algal–bacterial consortia. While the highest biomass removals (66–98%) for the ferric salts were achieved at concentrations of 150–250 mg L −1, dosages of 25–50 mg L −1 were required for the polymer flocculants to support comparable removal efficiencies. Process efficiency declined when the polymer flocculant was overdosed. Biomass concentration did not show a significant impact on flocculation within the concentration range tested. The high flocculant requirements herein recorded might be due to the competition of colloidal organic for the flocculants and the stationary phase conditions of biomass.