Journal ArticleDOI
Aeration optimization through operation at low dissolved oxygen concentrations: Evaluation of oxygen mass transfer dynamics in different activated sludge systems.
TLDR
Results showed that the activated sludge system could meet effluent criteria when DO was as low as 0.3mg/L, and that nitrifier communities cultivated under low DO conditions had higher oxygen affinity than those cultivated under high DO conditions, as indicated by the oxygen half-saturation constant and nitrification ability.Abstract:
In wastewater treatment plants (WWTPs) using the activated sludge process, two methods are widely used to improve aeration efficiency - use of high-efficiency aeration devices and optimizing the aeration control strategy. Aeration efficiency is closely linked to sludge characteristics (such as concentrations of mixed liquor suspended solids (MLSS) and microbial communities) and operating conditions (such as air flow rate and operational dissolved oxygen (DO) concentrations). Moreover, operational DO is closely linked to effluent quality. This study, which is in reference to WWTP discharge class A Chinese standard effluent criteria, determined the growth kinetics parameters of nitrifiers at different DO levels in small-scale tests. Results showed that the activated sludge system could meet effluent criteria when DO was as low as 0.3mg/L, and that nitrifier communities cultivated under low DO conditions had higher oxygen affinity than those cultivated under high DO conditions, as indicated by the oxygen half-saturation constant and nitrification ability. Based on nitrifier growth kinetics and on the oxygen mass transfer dynamic model (determined using different air flow rate (Q'air) and mixed liquor volatile suspended solids (MLVSS) values), theoretical analysis indicated limited potential for energy saving by improving aeration diffuser performance when the activated sludge system had low oxygen consumption; however, operating at low DO and low MLVSS could significantly reduce energy consumption. Finally, a control strategy coupling sludge retention time and MLVSS to minimize the DO level was discussed, which is critical to appropriate setting of the oxygen point and to the operation of low DO treatment technology.read more
Citations
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Measurement of Oxygen Transfer in Clean Water
TL;DR: The International Measurement of Oxygen Transfer in Clean Water (IMeasurement of Clean Water N) as discussed by the authors was developed to calculate the rate of oxygen transfer from diffused gas and mechanical oxygenation devices to water.
Journal ArticleDOI
Electric field induces electron flow to simultaneously enhance the maturity of aerobic composting and mitigate greenhouse gas emissions.
Jiahuan Tang,Li Xiang,Wenqi Zhao,Yajun Wang,Peng Cui,Raymond Jianxiong Zeng,Linpeng Yu,Shungui Zhou +7 more
TL;DR: It is suggested that the electric field is an effective and environmentally friendly strategy for enhancing compost maturity and mitigating GHG emissions during aerobic composting.
Journal ArticleDOI
Enhanced biological nitrogen removal under low dissolved oxygen in an anaerobic-anoxic-oxic system: Kinetics, stoichiometry and microbial community
TL;DR: Improved simultaneous nitrification and denitrification under low DO conditions contributed to the enhanced nitrogen removal.
Journal ArticleDOI
Ammonium removal mechanisms in a microalgal-bacterial sequencing-batch photobioreactor at different solids retention times
TL;DR: It is shown that the SRT is a key operational parameter that allows controlling the nutrient removal processes and growth of microalgal-bacterial consortia.
Journal ArticleDOI
Nitrification kinetics and microbial communities of activated sludge as a full-scale membrane bioreactor plant transitioned to low dissolved oxygen operation
TL;DR: In this article, a Water Recycling Plant successfully transitioned its aeration tank dissolved oxygen from moderate (0.8 mg/L) to low ( 0.3mg/L), achieving an energy efficient and environment friendly facility for producing reclaimed water.
References
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Standard methods for the examination of water and wastewater
TL;DR: The most widely read reference in the water industry, Water Industry Reference as discussed by the authors, is a comprehensive reference tool for water analysis methods that covers all aspects of USEPA-approved water analysis.
Book
Wastewater engineering : treatment and reuse
TL;DR: In this article, the authors present an overview of wastewater engineering and its application in the field of wastewater treatment, including conversion factors, physical properties of selected gases and the composition of air, and water properties.
Book
Environmental Biotechnology: Principles and Applications
TL;DR: This paper describes the development of biofilm Kinetics and its applications in water treatment, as well as some of the systems used for detoxification of Hazardous Chemicals.
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