Article
Microbiology
Xiafei Zheng, Zhongneng Yan, Chenxi Zhao, Lin He, Zhihua Lin, Minhai Liu
Summary: This study investigated the diversity, dynamics, drivers, and assembly mechanisms of total bacteria, napA, and nosZ denitrifiers in intensive shrimp aquaculture ponds. The results showed that the diversity of the total bacterial community increased over time, while the diversity of napA and nosZ bacteria remained stable. The community structure changed significantly over the culture period and multiple factors were identified as drivers of the denitrifying bacterial communities. Network analysis revealed complex co-occurrence patterns between total, napA, and nosZ bacteria, which fluctuated over time. The null model approach showed that napA and nosZ bacteria were primarily governed by deterministic processes. The findings provide important ecological insights for optimizing microbial community structure and function.
FRONTIERS IN MICROBIOLOGY
(2023)
Article
Fisheries
Hua Li, Yafei Duan, Hongbiao Dong, Jiasong Zhang
Summary: In order to solve the nitrate accumulation in recirculating aquaculture system (RAS), this study aimed to provide organic carbon source, denitrifying bacteria, and microenvironment for denitrification. Denitrifying capsules were prepared and their morphology, microbial community, and nitrogen removal efficiency were investigated. The denitrifying capsules had a porous structure and showed good adaptability to environmental conditions. They exhibited high nitrate removal rates even at low solid-to-liquid ratios or low temperatures. The denitrification process of the capsules followed a zero-order reaction and the denitrification rate was calculated to be 109.0 mg N/L-capsule dot h. The capsules showed a high nitrate removal rate until the litchi powder was exhausted.
Article
Agricultural Engineering
Wilasinee Kotcharoen, Takahiro Watari, Nur Adlin, P. Thao Tran, Penpicha Satanwat, Wiboonluk Pungrasmi, Sorawit Powtongsook, Yutaka Takeuchi, Masashi Hatamoto, Shinichi Yamazaki, Takashi Yamaguchi
Summary: This study evaluated the performance of a laboratory-scale anaerobic baffled reactor (ABR) - downflow hanging sponge (DHS) system for treating black wastewater from a closed recirculating aquaculture system (RAS) with a salinity of 15 parts per thousand. The results showed that the ABR achieved a nitrate removal efficiency of 95-99 % at TOC/TN ratios higher than 1.8, but significantly decreased to 12 % when the ratio decreased to 0.3. The highest removal efficiency for total nitrogen and suspended solids was achieved with a TOC/TN ratio of 3.0.
AQUACULTURAL ENGINEERING
(2023)
Article
Agricultural Engineering
Shuohui Shi, Lei He, Ying Zhou, Xing Fan, Ziyuan Lin, Xuejie He, Jian Zhou
Summary: This study investigated the response of a thermophilic denitrification system (50 degrees C) to a wide range of pH (3-11) and found that it could adapt to pH 5-11 but suffered from nitrite and ammonia accumulation at pH 3. The enrichment of specific functional thermophiles contributed to the tolerance towards unfavorable pH, and the selection advantage of nitrate reducing bacteria and the enrichment of DNRA bacteria were responsible for the nitrite and ammonia accumulation at pH 3. Functional gene prediction denoted higher narG/(nirK + nirS) and nrfA at pH 3, facilitating partial denitrification and DNRA.
BIORESOURCE TECHNOLOGY
(2022)
Article
Fisheries
Prasannan Geetha Preena, Vattiringal Jayadradhan Rejish Kumar, Isaac Sarojini Bright Singh
Summary: One of the major challenges in sustainable aquaculture production systems is the accumulation of nitrogenous waste. By establishing in situ nitrification and denitrification through biofilters/bioreactors activated with nitrifying/denitrifying bioaugmentors, total nitrogen removal can be achieved without external carbon supplements or additional anaerobic compartment. The structure and population dynamics of nitrifying/denitrifying consortia in recirculating aquaculture systems are influenced by environmental factors, which are crucial for the success of the processes.
REVIEWS IN AQUACULTURE
(2021)
Article
Biotechnology & Applied Microbiology
Kittikoon Sucunthowong, Jay H. Lee, Sorawit Powtongsook, Kasidit Nootong
Summary: By cultivating tilapia in an air-tight tank of a recirculating aquaculture system, CO2 is produced for the growth of Scenedesmus armatus in photobioreactors. It was found that the CO2 concentrations in the tank were higher than in the atmosphere, and using the captured CO2 and nitrate from tilapia farm effluent enhanced algal biomass production. This study demonstrates the potential of repurposing CO2 from aquaculture systems to enhance algal cultivation.
ALGAL RESEARCH-BIOMASS BIOFUELS AND BIOPRODUCTS
(2023)
Article
Engineering, Environmental
Jianxiong Jian, Xiaojian Liao, Shoupeng Li, Shaojin Chen, Zhenhua Huang, Junhao Chen, Xingfan Zhou, Yumin Zhang, Baixuan Yin, Shuiyu Sun, Zhijie Guan
Summary: The simultaneous anammox and denitrification (SAD) process was applied to treat industrial recirculating aquaculture systems wastewater, resulting in high nitrogen removal rates. The optimal working parameters were determined to achieve efficient removal of ammonium, nitrite, and total nitrogen. Changes in granular sludge properties and bacterial community structure were observed.
JOURNAL OF WATER PROCESS ENGINEERING
(2022)
Article
Engineering, Environmental
Jianping Xu, Tianlong Qiu, Fudi Chen, Li Zhou, Yishuai Du, Jianming Sun
Summary: In this study, electrocoagulation (EC) technology was used to improve the performance of Litopenaeus vannamei (L. vannamei) recirculating aquaculture system (RAS) and investigate the nitrogen migration law and recovery strategy. The findings showed that EC significantly enhanced nitrogen removal in RAS, and Chlorella vulgaris was effective in recovering waste nitrogen from the system.
JOURNAL OF WATER PROCESS ENGINEERING
(2022)
Article
Environmental Sciences
Julia Clols-Fuentes, Julien A. Nguinkal, Patrick Unger, Bernd Kreikemeyer, Harry W. Palm
Summary: Fish farming in Recirculating Aquaculture Systems (RAS) is a sustainable and efficient practice. This study analyzed the influence of different stocking densities on the water microbiome composition and identified bacterial pathogens associated with common fish farming practices. The results showed that microbiomes differ across systems and sampling points, and fish biomass and water physicochemical properties affect the microbiome.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Biotechnology & Applied Microbiology
Shiyang Zhang, Zhiwei Tang, Shibin Xia, Yinghe Jiang, Meng Li, Bing Wang
Summary: The study investigated the effect of nitrate loading rate (NLR) on the treatment performance of solid-phase denitrification (SPD) systems. Results showed that the denitrification efficiency was high and stable, except at the highest NLR, which lacked available carbon sources. The bacterial community structure was mainly influenced by NLR rather than the filling ratio. Nitrogen metabolism pathways included denitrification, dissimilatory nitrate reduction to ammonium (DNRA), assimilatory nitrate reduction to ammonium (ANRA), and nitrogen fixation. These findings have practical applications.
Article
Fisheries
Wenchang Liu, Bo Xu, Hongxin Tan, Songming Zhu, Guozhi Luo, Abubakar Shitu, Yumei Wan
Summary: In this study, two nitrifying suspended growth bioreactor processes based on biofloc technology were investigated in recirculating aquaculture systems. The conversion of nitrifying bioreactor to denitrifying biofilter via adding carbohydrates was studied. The results showed that the dominant functional microbes in the nitrifying biofilters were ammonia-oxidizing bacteria, denitrifying bacteria, phosphorus/glycogen accumulating organisms, and nitrite-oxidizing bacteria. The addition of carbohydrates significantly improved the removal efficiency of nitrate and soluble reactive phosphate.
Article
Agricultural Engineering
Talvikki Suhonen, Raed A. Al-Juboori, Antonina Kruglova, Jani Pulkkinen, Jouni Vielma, Anna Mikola
Summary: This study evaluates the feasibility of using aerobic granular sludge (AGS) to treat recirculating aquaculture system (RAS) effluent. The AGS process shows promising results for nutrient removal, with the ability to restore performance after acclimating to a change in feed. Illumina sequencing reveals diverse microbial communities in the AGS, indicating its potential for heterotrophic, denitrifying, and phosphorus-accumulating processes. Further development is needed to address energy consumption in aeration and carbon addition.
AQUACULTURAL ENGINEERING
(2023)
Article
Agricultural Engineering
Shiyang Zhang, Longqu Xiao, Zhiwei Tang, Xiangling Zhang, Zhi Wang
Summary: This study investigated the fluctuating profiles of physicochemical and microbial characterizations along different filling heights of continuously up-flow solid-phase denitrification columns packed with PCL. It was found that both the PCL filling area and non-filling area significantly contributed to treatment performance, with denitrification mainly occurring near the bottom of the filling column. Nitrate showed high removal rates, while nitrite and ammonium displayed weak accumulation in final effluents.
BIORESOURCE TECHNOLOGY
(2022)
Article
Fisheries
Zhao Chen, Zhiqiang Chang, Ling Qiao, Jiajia Wang, Yunfeng Liu, Xiefa Song, Jian Li
Summary: The study revealed that hydraulic retention time (HRT) significantly influences the performance of solid-phase denitrification reactors, affecting denitrification efficiency and bacterial community structure. Under optimal HRT conditions, solid-phase denitrification reactors can achieve the best denitrification effect and promote the growth of total bacteria.
Article
Environmental Sciences
Petra Camilla Lindholm-Lehto, Jani Tapio Pulkkinen, Tapio Kiuru, Juha Koskela, Jouni Vielma
Summary: A passive water treatment system was designed for a recirculating aquaculture system to improve water quality, nutrient removal, and water reuse. The denitrification efficiency in the system remained high, reaching a nitrogen removal rate of 15 g NO3-N m(-3) per day. The system also effectively reduced concentrations of harmful substances such as heavy metals and off-flavor-inducing compounds, indicating its suitability for producing high quality fish.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2021)