Removal of Organics and Nutrients from Urban Wastewater by Galdieria Sulphuraria

Download or read book Removal of Organics and Nutrients from Urban Wastewater by Galdieria Sulphuraria written by Shanka M. Henkanatte Gedara and published by . This book was released on 2015 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: Currently, urban wastewaters (UWW) laden with organic carbon (BOD) and nutrients (ammoniacal nitrogen, N, and phosphates, P) are treated in multi-stage, energy-intensive process trains to meet the mandated discharge standards. With current recognition of UWWs as a renewable resource from which water, energy, nutrients, and useful chemicals could be reclaimed for beneficial use, publically owned treatment works (POTW) are searching for energy efficient, sustainable approaches to treat urban wastewaters. This study was developed and undertaken as part of the multi-disciplinary algal research effort at New Mexico State University to validate the fundamentals of a Photosynthetically Oxygenated Waste to Energy Recovery (Power) system as a sustainable, energy-positive approach to treat urban wastewater. The stoichiometric analysis of algal processes conducted in first phase of the study demonstrated the energy advantage and positive CO2 abatement potentials of mixed algal/bacterial system and mixotrophic algal system compared to the traditional activated sludge process. Evaluation of the C:N:P ratios validated the premise that algal-based systems are capable of single-step treatment of wastewater due to their C:N ratio being closer to that of the wastewaters and due to photosynthetic carbon fixation. In second phase of study, laboratory experiments conducted to validate the feasibility of acidophilic, thermotolerant algal species, Galdieria sulphuraria as a preferred strain for POWER system demonstrated high removal rates of BOD, N, and P (of 14.93, 7.23, and 1.38 mg L−1 day−1 respectively) which are comparable to literature reports. The growth capability of G. sulphuraria in raw primary effluent in comparison to growth in synthetic growth medium validated the fact that this particular strain is preferred for algal based watewater treatment; higher biomass yield observed with wastewater media demonstrated the energy advantage of G. sulphuraria due to its mixotrophic metabolism. These results confirm the premise of the POWER system as a sustainable technology for wastewater treatment, with potential for higher recovery of energy and nutrient than by current practice and validate the feasibility of G. sulphuraria as a preferred strain for use in the POWER system for urban wastewater treatment.