dc.contributor.author	Jia, Huijun
dc.contributor.examiningcommittee	Oleszkiewicz, Jan (Civil Engineering) Sparling, Richard (Microbiology)	en_US
dc.contributor.supervisor	Yuan, Qiuyan (Civil Engineering)	en_US
dc.date.accessioned	2018-06-06T19:02:11Z
dc.date.available	2018-06-06T19:02:11Z
dc.date.issued	2018	en_US
dc.date.submitted	2018-05-28T21:49:17Z	en
dc.date.submitted	2018-06-05T22:18:52Z	en
dc.degree.discipline	Civil Engineering	en_US
dc.degree.level	Master of Science (M.Sc.)	en_US
dc.description.abstract	Exceeding nitrogen discharge into natural water bodies can lead to eutrophication in natural aquatic environments, as well as the decline in shellfish habitat and aquatic plant life. Currently, bacterial biological treatment process is the most common process employed in wastewater treatment plants, which requires extensive oxygen. The large demand for oxygen provided by mechanical aeration is costly and can strip out volatile compounds. Microalgae are photosynthetic micro-organisms can be a good source of oxygen in the wastewater treatment process. The effect of using microalgae, either solo or in consortia systems along with other micro-organisms (mainly bacteria) have been studied by researchers to improve their contaminant removal efficiency. In a consortia system, microalgae generate oxygen through photosynthesis to satisfy the oxygen requirement of bacteria. Simultaneously, they also remove contaminating nutrients, nitrogen and phosphorus, throughout their growth cycle. Various factors affect the performance of the consortia systems such as lighting, pH, and species of microalgae and bacteria. Since microalgae are typically suspended and dispersed in the media, harvesting is crucial to achieving a high-quality effluent. The effects of ammonium nitrogen concentration, algae biomass concentration, and light conditions (wavelength and intensity) on the ammonium removal efficiency of algae-bacteria consortia from wastewater were investigated in initial short term small scale experiments. The results indicated that ammonium concentration and light intensity had a significant impact on nitrification. It was found that the highest NH4+-N concentration (430 mg N/L) in the influent resulted in the highest ammonia removal rate of 108 ± 3.6 mg N/L/days, which was two times higher than for the influent with low NH4+-N concentration (40 mg N/L). At the lowest light intensity of 1000 Lux, algae biomass concentration, light wavelength, and light cycle did not showa significant effect on the performance of algal–bacterial consortium. Furthermore, the NH4+-N removal rate was approximately 83 ± 1.0 mg N/L/days, which was up to 40% faster than at the light intensity of 2500 Lux. It was concluded that the algae-bacteria consortia can effectively remove nitrogen from wastewater and the removal performance can be stabilized and enhanced using the low light intensity of 1000 Lux that is also a cost-effective strategy. To evaluate the effect of photoperiod on consortium performance in long-term low-light intensity, a photo batch sequence reactor was operated under 24 hours’ illumination and 16h/8h light-dark cycle alternately. After the stabilization phase, a constant NH4+-N removal rate of 60 mgN/L/d was achieved for both photoperiods. Without loading organic carbon in the wastewater, maximum denitrification efficiency of 28% was achieved in photoperiod of 16h/8h, which was 36% higher compared to that achieved under continuous lighting condition. Less biomass was produced with photoperiod of 16h/8h L/D even though similar NH4+-N removal rate and higher denitrification rate were achieved. Biomass settled within half an hour of the start of the experiment with a sludge volume index (SVI) of 109 ml/g. The results indicate a sustainable way for reduced energy consumption and provide a way to reduce bio-waste production by treating wastewater with algae-bacteria consortia.	en_US
dc.description.note	October 2018	en_US
dc.identifier.citation	Jia, H.J., Yuan, Q.Y. (2016). Removal of nitrogen from wastewater using microalgae and microalgae–bacteria consortia. Cogent Environmental Science 2 (1), 1-15.	en_US
dc.identifier.citation	Jia, H.J., Yuan, Q.Y. (2018). Ammonium removal using algae–bacteria consortia: the effect of ammonium concentration, algae biomass, and light. Biodegradation 29 (2), 105-115.	en_US
dc.identifier.uri	http://hdl.handle.net/1993/33049
dc.language.iso	eng	en_US
dc.publisher	Removal of nitrogen from wastewater using microalgae and microalgae–bacteria consortia.	en_US
dc.publisher	Ammonium removal using algae-bacteria consortia: the effect of ammonium concentration, algae biomass, and light.	en_US
dc.rights	open access	en_US
dc.subject	Nitrogen removal, Algae-bacteria consortia, Photoperiod, Low light intensity	en_US
dc.title	Nitrogen removal by algae-bacteria consortia: batch tests and photo sequence batch reactor	en_US
dc.type	master thesis	en_US

Nitrogen removal by algae-bacteria consortia: batch tests and photo sequence batch reactor

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