Biological nutrients eradication employing Aerobic Granulation
Creators: name: Not Available, Anrish
Publisher: name: Graduate Studies
Year: 2018
Subjects: subject: Aerobic Granulation
subject: Nutrients removal
subject: Phosphorus removal
subject: Engineering
subject: Engineering--Civil
subject: Engineering--Environmental

description: Nutrients (nitrogen and phosphorus), since mid-20th century, have been a rising matter of concern- impacting the quality of natural water bodies and stressing the wastewater treatment facilities. The increased availability of nitrogen and phosphorus are known to cause the excessive aging of lakes, eutrophication, thus depriving these bodies of oxygen, leading to various ecological, human health and socio-economic impacts. The phosphorus discharged from untreated or under treated municipal wastewater considerably adds to eutrophication. Although the conventional processes for wastewater treatment are able to remove the organics yet contains residual nutrients in the effluent. These residual amounts exceed the desired effluent limitations, which are getting stringent. The following research provides an insight of an emerging biotechnology: Aerobic Granulation, for its suitability to remove phosphorus (growth limiting nutrient) and nitrogen existing in domestic wastewater. The research focuses on investigation of different mechanisms supporting domestic level phosphorus removal in aerobic granular system. Granulation is a novel biotechnology based on self-immobilization of diverse microbes into a packed and dense structure giving it a unique ability to retain higher biomass, exceptional settleability, and resistance to toxicity and fluctuating organic loadings. In comparison to the conventional treatment processes, granulation technology also offers smaller footprint and low operational cost. A characteristic property of the granules is that these can be tailored as per the treatment requirements. The stratified structure of the granules due to mass transfer diffusion provides favorable conditions for phosphorus removal. The co-existence of aerobic zone and anaerobic zone in the granules, as documented in the literature, supports the simultaneous removal of nitrogen and phosphorus. The lab-scale bioreactor was setup in Hydraulics lab at University of Calgary from February 2016- August 2016. Synthetic wastewater was used for the experiments with variation in COD and phosphorus concentration in the reactor for evaluating the significance of the operational factors. The major phenomenon responsible for phosphorus removal at low C:P was biological assimilation. At a high C:P ratio, biological accumulation and biologically induced phosphorus precipitation were identified as the phosphorus removal phenomena. Microbiological analysis through Polymerase chain reaction of extracted 16r RNA genes indicated the presence of Rhodocyclaceae; phosphorus removing bacteria with a low temperature based biological phosphorus removal rate. Data analysis illustrated a significance of C:P on aerobic granular phosphorus removal process. The results reflect the suitability of aerobic granulation for municipal level phosphorus removal provided optimum operational conditions are maintained. A scale up version of this technology could be used for deeper insight into real domestic wastewater for advanced wastewater treatment processes.