Article
Engineering, Environmental
Yasuyuki Takemura, Wilasinee Yoochatchaval, Tsuyoshi Danshita, Yuma Miyaoka, Masataka Aoki, Thao P. Tran, Noriko Tomioka, Yoshitaka Ebie, Kazuaki Syutsubo
Summary: This study introduces a novel post-treatment process for sewage treatment systems, the down-flow hanging sponge (DHS) reactor. Through a pilot-scale experiment, it is demonstrated that the DHS reactor can effectively remove suspended solids, biochemical oxygen demand, and ammonium nitrogen in sewage, as well as reduce the concentration of fecal indicator bacterium Escherichia coli and potentially pathogenic bacterial group Arcobacter spp. under relatively short hydraulic retention times (HRT).
JOURNAL OF WATER PROCESS ENGINEERING
(2022)
Review
Biotechnology & Applied Microbiology
Vinay Kumar Tyagi, Muntjeer Ali, Ahmed Tawfik, Namita Maharjan, A. A. Kazmi, Tsutomu Okubo, Hideki Harada
Summary: The down-flow hanging sponge (DHS) process is a cost-effective wastewater treatment technology with advantages of simple control, low cost, and energy efficiency. Through extensive testing under different operational conditions, the DHS module has been successfully scaled up to full-size demonstration plants.
REVIEWS IN ENVIRONMENTAL SCIENCE AND BIO-TECHNOLOGY
(2021)
Article
Biotechnology & Applied Microbiology
Takahiro Watari, Osamu Wakisaka, Yuya Sakai, Yuga Hirakata, Daisuke Tanikawa, Masashi Hatamoto, Fuminori Yoneyama, Takashi Yamaguchi
Summary: A combination of UASB and DHS systems was used to treat water-soluble copolymer wastewater, achieving a COD removal efficiency of 86%. The UASB reactor enhanced biodegradability of the wastewater, while the DHS reactor primarily reduced the molecular weight of the wastewater.
ENVIRONMENTAL TECHNOLOGY & INNOVATION
(2021)
Article
Fisheries
Takahiro Watari, Yoshinobu Nakamura, Wilasinee Kotcharoen, Yuga Hirakata, Penpicha Satanwat, Wiboonluk Pungrasmi, Sorawit Powtongsook, Yutaka Takeuchi, Masashi Hatamoto, Takashi Yamaguchi
Summary: The combined pilot-scale system of DHS reactors and USB reactors effectively removed nitrogen and maintained water quality in a recirculating aquaculture system for longtooth groupers. The high survival rate and growth rate of fish in the study suggest that the DHS-USB system is a novel and applicable method for nitrogen removal in aquaculture systems, recommending further large-scale studies.
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
Biochemical Research Methods
Hiroyuki Imachi, Masaru K. Nobu, Masayuki Miyazaki, Eiji Tasumi, Yumi Saito, Sanae Sakai, Miyuki Ogawara, Akiyoshi Ohashi, Ken Takai
Summary: This article describes a two-stage bioreactor-mediated approach for culturing previously uncultured microorganisms, involving enrichment and subsequent selective batch cultivation. The method allows for the isolation of pure syntrophic co-cultures, overcoming the limitations of conventional methods for uncovering uncultured microorganisms in nature.
Article
Biotechnology & Applied Microbiology
Shehani Sharadha Maheepala, Masashi Hatamoto, Yuki Mitsuishi, Takahiro Watari, Takashi Yamaguchi
Summary: The study aims to enhance denitrification by developing a low-cost down-flow hanging sponge (DHS). The DHS reactor was modified to maintain aerobic and anaerobic conditions by connecting with a syphon tube. This method allows simultaneous nitrification and denitrification without the need for extra pumping energy.
ENVIRONMENTAL TECHNOLOGY & INNOVATION
(2023)
Article
Environmental Sciences
Nga T Dinh, T Hiep Nguyen, Arvind Kumar Mungray, La Duc Duong, Nguyen-Tri Phuong, D Duc Nguyen, W. Jin Chung, S. W. Chang, Phan D Tuan
Summary: This study investigated the effect of salinity on the removal of organic matter and nitrogen concentrations in a bioreactor using a hybrid bench scale DHS system. Results showed that as salinity increased, the removal efficiency of COD, BOD5, NH4+-N, and TN gradually decreased, with corresponding changes in biofilm characteristics.
Review
Environmental Sciences
Jose A. Contreras, Edgardo I. Valenzuela, Guillermo Quijano
Summary: This study provides an overview of the recent developments in nitrate/nitrite-dependent anaerobic oxidation of methane (N-AOM), including the fundamental principles, microbiology, reactor configurations, and operational conditions. The potential advantages of the N-AOM process over aerobic methanotrophic biotechnologies are discussed, as well as the challenges of implementing this biotechnology at full scale.
JOURNAL OF ENVIRONMENTAL MANAGEMENT
(2022)
Article
Engineering, Environmental
Xin Tan, Yang Lu, Wen-Bo Nie, Guo-Jun Xie, Paul Evans, Xiao-Wei Wang, Cheng-Cheng Dang, Zhi-Cheng Zhao, Sheng-Qiang Fan, Nanqi Ren
Summary: This study demonstrates that excessive nitrite is an important driver of N2O production by n-DAMO bacteria. Higher initial nitrite concentrations lead to increased quantities of N2O being formed. Metatranscriptomic analyses reveal that nitrite reductase (nirS) and nitric oxide reductase (norZ) genes from n-DAMO bacteria are responsible for N2O production. Proper monitoring and control of nitrite levels in wastewater treatment plants would be an effective strategy for mitigating N2O emissions.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Environmental Sciences
Renata Gruca-Rokosz, Dorota Szal
Summary: This research demonstrates the presence of anaerobic oxidation of methane (AOM) in reservoir sediments, with variations observed among different reservoirs and sediment layers. Factors affecting AOM include sediment pH, organic matter quality, pore water salinity, and the presence of AOM microorganisms.
Review
Biotechnology & Applied Microbiology
R. B. Costa, P. N. L. Lens, E. Foresti
Summary: Anaerobic technologies play a crucial role in sewage treatment and recovering marketable products from waste, but they often lead to methane oversaturation and lack of nitrogen removal. However, combining methane oxidation with denitrification processes can address both issues simultaneously.
CRITICAL REVIEWS IN BIOTECHNOLOGY
(2022)
Article
Engineering, Environmental
Choerudin Choerudin, Fauziyah Istiqomah Arrahmah, Jonatan Kevin Daniel, Takahiro Watari, Takashi Yamaguchi, Tjandra Setiadi
Summary: The study evaluated the performance of textile wastewater treatment using an AnMBR-DHS combination, with the microbial community in AnMBR reportedly capable of reducing azo dyes and the microbial community in DHS reportedly able to degrade sulfonated aromatic amines.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2021)
Article
Environmental Sciences
Daisuke Tanikawa, Daisuke Motokawa, Yuya Itoiri, Zen-Ichiro Kimura, Masahiro Ito, Akihiro Nagano
Summary: This study uses a TSDHS reactor as a biotrickling filter for biogas desulfurization, achieving efficient removal of hydrogen sulfide and nitrogen in the sewage sludge.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Engineering, Environmental
Takahiro Watari, Yoshihiro Kirishima, Pairaya Choeisai, Hideki Harada, Wilasinee Kotcharon, Takashi Matsueda, Nobuhiro Tanaka, Shuji Kawakami, Masashi Hatamoto, Takashi Yamaguchi
Summary: In this study, a compact package-type down-flow hanging sponge (DHS) operating system was designed and installed. The DHS system achieved the discharge standard quickly and showed high efficiencies in removing organics and nitrogen. The study also found that the DHS sponge media effectively retained slow-growth nitrifying bacteria.
JOURNAL OF WATER PROCESS ENGINEERING
(2022)
Article
Environmental Sciences
Chiho Murakami, Koshi Machida, Yoichi Nakao, Tomonori Kindaichi, Akiyoshi Ohashi, Yoshiteru Aoi
Summary: The study found that there is a mutualistic symbiotic relationship between Nitrospira and heterotrophs, where some heterotrophs can promote the growth of Nitrospira and provide growth-promoting factors to them.
ENVIRONMENTAL MICROBIOLOGY REPORTS
(2022)
Article
Water Resources
Takashi Onodera, Tsutomu Okubo, Daisuke Takayama, Kazuaki Syutsubo, Takashi Yamaguchi, Shigeki Uemura, Akiyoshi Ohashi, Hideki Harada
Summary: The study evaluated the impact of shock-loading on the performance of a full-scale DHS reactor treating municipal sewage with up-flow anaerobic sludge blanket. The results demonstrated that the reactor is resilient to organic shock-loadings, maintaining stable operation and quickly returning to steady state after restart.
WATER PRACTICE AND TECHNOLOGY
(2022)
Article
Biotechnology & Applied Microbiology
Nor Asyikin Ismail, Norhafezah Kasmuri, Nurhidayah Hamzah, Jurina Jaafar, Amin Mojiri, Tomonori Kindaichi
Summary: The bioremediation of benzo[a]pyrene was studied using Sphingobacterium spiritivorum and Aspergillus brasiliensis. Batch culture experiments were conducted to determine the optimum conditions for bacterial and fungal growth. The results showed that the fungi exhibited a higher removal percentage of benzo[a]pyrene than the bacteria in wastewater.
ENVIRONMENTAL TECHNOLOGY & INNOVATION
(2023)
Article
Environmental Sciences
Hiromi Kambara, Ha T. T. Dinh, Shuji Matsushita, Yoshiteru Aoi, Tomonori Kindaichi, Noriatsu Ozaki, Akiyoshi Ohashi
Summary: Microbial electrosynthesis system (MES) is a promising method for methane production from carbon dioxide. This study demonstrates the possibility of electrotrophic methane production coupled with HS oxidation at a low applied voltage. Microbial community analysis reveals the probable pathways for methane production in the bioanode and biocathode.
JOURNAL OF ENVIRONMENTAL SCIENCES
(2023)
Article
Engineering, Chemical
Federico Micolucci, Jonathan A. C. Roques, Geoffrey S. Ziccardi, Naoki Fujii, Kristina Sundell, Tomonori Kindaichi
Summary: Recirculating aquaculture systems (RAS) are a promising solution for sustainable aquaculture development. However, a limitation of RAS is the accumulation of nitrogenous wastes, which can have negative impacts on fish health. In this study, we investigated the potential of marine anammox bacteria to treat RAS wastewater. The results showed that the bacteria can successfully treat marine RAS wastewater.
Article
Environmental Sciences
Amin Mojiri, John L. Zhou, Noriatsu Ozaki, Bahareh KarimiDermani, Elham Razmi, Norhafezah Kasmuri
Summary: This study explains the accumulation of different PFAS in water bodies, showing a wide range of PFAS concentrations and varying levels of bioaccumulation in fish and water biota. Recent research has focused on removing PFAS from aqueous solutions, with advanced oxidation processes (AOPs) being a promising technique. Developing novel, efficient, cost-effective, and sustainable AOPs for PFAS degradation in water treatment systems is critical.
Article
Engineering, Environmental
Noriatsu Ozaki, Makoto Funaki, Tomonori Kindaichi, Akiyoshi Ohashi
Summary: The decrepitude of infrastructure in developed countries, including Japan, poses a threat to their stability. Therefore, it is crucial to develop efficient management and maintenance techniques. In urban areas, poor maintenance has led to the worsening leakage and destruction of separate domestic sewer pipelines that have been in existence for over 60 years, resulting in potential subsurface and surface water pollution. A study was conducted to examine urban stormwater pollution caused by domestic sewer leakages, measuring the concentrations of domestic-use chemicals and polycyclic aromatic hydrocarbons (PAHs) in storm drains on no-rain days. The results showed higher concentrations of domestic-use chemicals at the final outlet of the storm drain compared to rainfall and puddle waters, while PAH concentrations were similar or higher in rainfall and puddle waters. The study identified two hot spots in the storm drain networks, indicating the possibility of leakages from household discharges and misconnections to old sewer pipelines. The study emphasized the importance of proper maintenance in old domestic sewer networks to mitigate risks to public health and highlighted the effectiveness of fragrance compounds as tracers for leakages.
ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY
(2023)
Article
Biotechnology & Applied Microbiology
Hiromi Kambara, Takahiro Shinno, Norihisa Matsuura, Shuji Matsushita, Yoshiteru Aoi, Tomonori Kindaichi, Noriatsu Ozaki, Akiyoshi Ohashi
Summary: Methane-oxidizing bacteria (MOB) are divided into Type I and Type II, which have different environmental preferences. The pH value was found to be a crucial factor influencing the MOB types. Type II thrived at low pH conditions, while Type I dominated at neutral pH conditions. Additionally, unknown bacterial groups with methane oxidation capability were discovered.
MICROBES AND ENVIRONMENTS
(2022)
Article
Biotechnology & Applied Microbiology
Naoki Fujii, Kyohei Kuroda, Takashi Narihiro, Yoshiteru Aoi, Noriatsu Ozaki, Akiyoshi Ohashi, Tomonori Kindaichi
Summary: In this study, the interactions between Patescibacteria and Chitinophagales in activated sludge were investigated using correlation analysis and metagenomic analysis. The results showed that these interactions are important for the survival of Patescibacteria in activated sludge ecosystems.
MICROBES AND ENVIRONMENTS
(2022)
Article
Engineering, Environmental
Rong-Gui Zhu, Chang-Gui Pan, Feng-Jiao Peng, Chao-Yang Zhou, Jun-Jie Hu, Kefu Yu
Summary: This comprehensive survey investigated the occurrence, bioaccumulation, and trophic magnification of parabens and their metabolite 4-HB in a marine food web. Results showed that parabens were the predominant pollutants in marine organisms, with significant bioaccumulation from sediments. The estimated trophic magnification factor indicated biomagnification for MeP and trophic dilution for 4-HB. Overall, the risks for humans consuming marine organisms were found to be low.
Article
Engineering, Environmental
Andres F. Torres-Franco, Deborah Leroy-Freitas, Cristina Martinez-Fraile, Elisa Rodriguez, Pedro A. Garcia-Encina, Raul Munoz
Summary: Anaerobic and microalgae-based technologies have emerged as sustainable alternatives for municipal wastewater treatment. However, the presence of viruses in the treated wastewater is a major concern for reuse applications. This study assessed the ability of these technologies to reduce viruses during secondary wastewater treatment. The results showed that all technologies were effective in reducing the concentration of viruses, with microalgae-based treatment exhibiting the highest potential for reducing the disinfection requirements of treated wastewater.
Article
Engineering, Environmental
Young Gwang Kim, Sae Yun Kwon, Spencer J. Washburn, Scott C. Brooks, Ji Won Yoon, Lucien Besnard
Summary: The study uses Hg isotope ratios to identify the sources and exposure pathways of mercury in bivalves, finding that dissolved Hg phases in the water column are the primary source and exposure pathway to bivalves. This provides new insights into using bivalves as bioindicators for sediment quality monitoring.
Article
Engineering, Environmental
Hui Geng, Ying Xu, Rui Liu, Dianhai Yang, Xiaohu Dai
Summary: This study investigates the effect of cation exchange resin (CER) on the sequential recovery of hydrogen and methane from anaerobic digestion (AD) and the corresponding mechanisms. The results show that CER can simultaneously enhance the production of hydrogen and methane by promoting the solubilisation, hydrolysis, and acidification of organic matter. Additionally, CER facilitates effective contact between bacteria and organic particulates and reduces the energy barrier for mass transfer during methane production. The study also reveals changes in the microbial community structure and metagenomics during the AD process.
Article
Engineering, Environmental
Xiaojing Lin, Zhan Jin, Shunfeng Jiang, Zhiquan Wang, Suqing Wu, Ke Bei, Min Zhao, Xiangyong Zheng
Summary: Dehumidification combined with addition of absorbent resin supplement (ARS) was used to achieve rapid evaporation of non-pretreated urine, resulting in high water evaporation efficiency and nutrient recovery.
Article
Engineering, Environmental
Yangli Che, Chaoran Lin, Shen Li, Jiao Liu, Longhai Zhu, Shilei Yu, Nan Wang, Haoshuai Li, Mutai Bao, Yang Zhou, Tonghao Si, Rui Bao
Summary: Hydrodynamic processes play a crucial role in the transmission of sediments, microbial assembly, and organic carbon redistribution in the ocean. Through experiments and analysis, we found that hydrodynamics shape the assembly of microbial communities and control the redistribution of different sourced organic carbon, thereby influencing microbial-mediated biogeochemical transformation.
Article
Engineering, Environmental
Chao Chen, Yu Yang, Nigel J. D. Graham, Zhenyu Li, Xingtao Yang, Zhining Wang, Nadia Farhat, Johannes S. Vrouwenvelder, Li -an Hou
Summary: The fouling of seawater reverse osmosis membranes is a persistent challenge in desalination. This study monitored the operational performance of a desalination plant for 7 years and the fouling development in different areas of membrane modules. The findings showed that operational performance declined over time and fouling mainly occurred at the feed side of the modules, with the highest microbial diversity. Keystone species like Chloroflexi and Planctomycetes played an important role in maintaining community structure and biofilm maturation. Polysaccharides, soluble microbial products, marine humic acid-like substances, and inorganic substances contributed to fouling. Overall, biofouling had a significant impact on membrane fouling after 7 years of operation.
Article
Engineering, Environmental
Dan Li, Jieyi Sun, Yibo Fu, Wentao Hong, Heli Wang, Qian Yang, Junhong Wu, Sen Yang, Jianhui Xu, Yunfei Zhang, Yirong Deng, Yin Zhong, Ping'an Peng
Summary: Sulfidation-oxidation treatment of magnetite (Fe3O4) enhances the production of dark center dot OH, which can efficiently degrade dissolved organic matter (DOM) and accelerate carbon cycling.
Article
Engineering, Environmental
Cheng Yu, Kaijun Wang, Kaiyuan Zhang, Ruiyang Liu, Pingping Zheng
Summary: This study implemented a microaerobic-aerobic configuration in a full-scale municipal wastewater treatment facility and investigated the effects on sludge characteristics, pollutant removal, microbial community, and granulation mechanisms. The results showed successful transition from flocculent-activated sludge to well-defined AGS after two months of operation. The primary pathways for pollutant removal were simultaneous nitrification, denitrification, and phosphorus removal. Moreover, the incorporation of internal separators induced shifts in the flow pattern, which promoted granulation.
Article
Engineering, Environmental
Zhe Zhang, Shaoyang Hu, Guangrong Sun, Wei Wang
Summary: Halogenated aromatic disinfection byproducts (DBPs), such as halogenated phenols, have garnered widespread attention due to their high toxicity and prevalence. This study reports on the analysis, occurrence, and cytotoxicity of a group of emerging halogenated aromatic DBPs, known as halogenated polyhydroxyphenols (HPPs), in drinking water.
Article
Engineering, Environmental
Shengyue Chen, Jinliang Huang, Peng Wang, Xi Tang, Zhenyu Zhang
Summary: Accurate prediction of river water quality is crucial for sustainable water management. This study introduces wavelet analysis and transfer learning techniques to assist LSTM modeling, proposing a newly coupled modeling approach that improves short-term prediction of river water quality.
Article
Engineering, Environmental
Bang Du, Xinmin Zhan, Piet N. L. Lens, Yifeng Zhang, Guangxue Wu
Summary: Efficient anaerobic digestion relies on the cooperation of different microorganisms with different metabolic pathways. This study investigated the effects of different operational modes and the addition of powdered activated carbon (PAC) on ethanol metabolic pathways. The results showed that the SBR mode and the presence of CO2 facilitated ethanol metabolism towards propionate production, while the CFR mode with extended solids retention time enriched Geobacter. Adjusting operational modes and PAC addition can modulate anaerobic ethanol metabolism and enrich Geobacter.
Article
Engineering, Environmental
Wanfa Wang, Si-Liang Li, Jun Zhong, Yuanbi Yi, Fujun Yue, Zenglei Han, Qixin Wu, Ding He, Cong-Qiang Liu
Summary: This study compares the carbon biogeochemical processes in karst and non-karst regions within large thermal stratified river-reservoir systems. The results demonstrate that karst reservoirs have a reduced potential for carbon emissions and highlight the importance of considering geologic settings to improve accuracy in regional and global CO2 emission estimates.
Article
Engineering, Environmental
Chunxia Jiang, Zelong Zhao, Dong Zhu, Xiong Pan, Yuyi Yang
Summary: This study analyzed the occurrence and distribution of antibiotic resistance genes (ARGs) in different environmental media of the Yangtze River using metagenomics. Core resistome dominated by multidrug resistance genes was found in all samples, while rare resistome dominated by various resistance genes was more prevalent in plasmids. Specific bacteria were identified as hosts for both core and rare resistomes, with high clinical concern ARGs found in the rare resistome. Particle-associated environment provided the most ideal conditions for resistome hosts. This study provided insights into the genetic locations of ARGs and the community assembly mechanisms of ARG hosts in freshwater environments.
Article
Engineering, Environmental
Yu Zhang, Yongtao He, Linchun Jia, Lei Xu, Zheng Wang, Yueling He, Ling Xiong, Xumeng Lin, Hong Chen, Gang Xue
Summary: By synergizing organic carbon source, thiosulfate, and zero-valent iron, efficient mixotrophic denitrification of oligotrophic secondary effluent can be achieved. Thiosulfate plays a vital role in promoting TN removal efficiency, while corrosion of Fe0 releases OH- to neutralize H+ from thiosulfate-driven denitrification, creating a suitable environment for denitrification. The coordination of thiosulfate and Fe0 maintains the dominance of Thiobacillus for denitrification.