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Shi-Peng Wang, Xiao-Zhong Zhong, Ting-Ting Wang, Zhao-Yong Sun, Yue-Qin Tang, Kenji Kida
Aerobic composting of distilled grain waste (DGW) at different initial pH values adjusted by CaO addition was investigated. Three pH-adjusted treatments with initial pH values of 4 (R1), 5 (R2) and 6 (R3) and a control treatment (R0) with a pH value of 3.5 were conducted simultaneously. The results showed that R0 had an unsuccessful start-up of composting. However, the pH-adjusted treatments produced remarkable results, with a relatively high initial pH being beneficial for the start-up. Within 65days of composting, the degradation of volatile solids (VS) and the physicochemical properties of R2 and R3 displayed similar tendencies, and both produced a mature end-product, while R1 exhibited a lower VS degradation rate, and some of its physicochemical properties indicated the end-product was immature...
September 8, 2017: Bioresource Technology
Yu Yang, Zhifei Ma, Yonghai Jiang, Xinying Lian, Beidou Xi, Yu Pei
The multi-layer enhanced groundwater remediation technology (MET) is an innovative platform that integrates physical chemistry, bioremediation, and phytoremediation technology to safely and effectively remediate ammonia nitrogen in groundwater. A nitrogen transformation model was established to study the mechanism of nitrogen transformation within ammonia nitrogen removal in the MET. The model considered organic nitrogen, ammonia nitrogen, and nitrate nitrogen as the variables, and ammonification, nitrification, denitrification, microbial assimilation, plant absorption, adsorption-desorption, and volatilization as the influencing factors...
September 19, 2017: Environmental Technology
Miaomiao Cheng, Anan Wang, Caixian Tang
Nitrogen fertilization has been shown to improve Cd uptake by plants but there is little information on the effect of N form. This study examined the effects of N form on Cd bioavailability and phytoextraction in two soils differing in pH. Plants of halophytic species Carpobrotus rossii were grown in an acidic Sodosol [pH (CaCl2) 4.9] and a neutral Vertosol (pH 7.2) spiked with 20 mg kg(-1) Cd as CdCl2. Three N forms, KNO3, (NH4)2SO4 and (NH2)2CO at a rate of 24 mg N kg(-1) were applied at weekly intervals, together with nitrification inhibitor dicyanodiamide...
September 11, 2017: Chemosphere
Subrat Kumar Mallick, Saswati Chakraborty
Objective of the present study was to simultaneously biodegrade synthetic petroleum refinery wastewater containing phenol (750 mg/L), sulphide (750 mg/L), hydrocarbon (as emulsified diesel of 300 mg/L), ammonia-nitrogen (350 mg/L) at pH >9 in anoxic-aerobic sequential moving bed reactors. The optimum mixing speed of anoxic reactor was observed at 20 rpm and beyond that, removal rate remained constant. In anoxic reactor the minimum hydraulic retention time was observed to be 2 days for complete removal of sulphide, 40-50% removal of phenol and total hydrocarbons and 52% of sulphur recovery...
September 18, 2017: Journal of Environmental Science and Health. Part A, Toxic/hazardous Substances & Environmental Engineering
Zhenzhen Li, Ling Zhang, Bangliang Deng, Yuanqiu Liu, Fanqian Kong, Guoxian Huang, Qin Zou, Qian Liu, Xiaomin Guo, Yanqiu Fu, Dekui Niu, Evan Siemann
Plant invasions may alter soil nutrient cycling due to differences in physiological traits between the invader and species they displace as well as differences in responses to anthropogenic factors such as nitrogen deposition and warming. Moso bamboo is expanding its range rapidly around the world, displacing diverse forests. In addition, near expansion fronts where invasions are patchy, moso bamboo and other species each contribute soil inputs. Nitrogen transformations and greenhouse gas (GHG) emissions are important processes associated with nutrient availability and climate change that may be impacted by bamboo invasions...
September 17, 2017: Environmental Science and Pollution Research International
Shanshan Li, Shijiang Gao, Sen Wang, Bingrui Ma, Liang Guo, Zhiwei Li, Qiaoyan Xu, Zonglian She, Mengchun Gao, Yangguo Zhao, Feng Gao, Chunji Jin
The performance, microbial community and enzymatic activity of a sequencing batch reactor (SBR) were evaluated at different silica nanoparticles (SiO2 NPs) concentrations. SiO2 NPs concentration at 5-30mg/L had a slight inhibitory impact on the nitrogen and COD removals, whereas the phosphorus removal was obviously inhibited at 30mg/L SiO2 NPs. The rates of nitrification, nitrite reduction and phosphorus removal decreased with the increase of SiO2 NPs concentration. The nitrate reduction rate decreased at less than 5mg/L SiO2 NPs and subsequently showed an increase at 10-30mg/L SiO2 NPs...
September 6, 2017: Bioresource Technology
María J Torres, Emilio Bueno, Andrea Jiménez-Leiva, Juan J Cabrera, Eulogio J Bedmar, Socorro Mesa, María J Delgado
The powerful greenhouse gas, nitrous oxide (N2O) has a strong potential to drive climate change. Soils are the major source of N2O and microbial nitrification and denitrification the main processes involved. The soybean endosymbiont Bradyrhizobium diazoefficiens is considered a model to study rhizobial denitrification, which depends on the napEDABC, nirK, norCBQD, and nosRZDYFLX genes. In this bacterium, the role of the regulatory cascade FixLJ-FixK2-NnrR in the expression of napEDABC, nirK, and norCBQD genes involved in N2O synthesis has been previously unraveled...
2017: Frontiers in Microbiology
Haolong Wang, Mingu Kim, Kai Li, Yuanyuan Shao, Jesse Zhu, George Nakhla
A lab-scale fluidized bed bioreactor with high-density polyethylene as biofilm carrier media was operated to study partial nitrification performance with high ammonia concentrations. The system was run at nitrogen loading rates (NLR) from 1.2 to 4.8 kg N/(m(3)·d) with empty bed contact time (EBCT) of 2.0 hrs and 2.7 hrs and four different influent ammonia concentrations of 100, 200, 300 and 400 mg/L. Dissolved oxygen concentration and temperature were maintained around 1.3 mg/L and 35˚C, respectively. Stable partial nitrification was successfully achieved during the whole period with low effluent NO3-N concentration at less than 15 mg/L, due to effective suppression of nitrite-oxidizing bacteria activity (NOB) at high concentrations of free ammonia (5...
September 15, 2017: Environmental Technology
Eugenio Marín, Jorge I Pérez, Miguel A Gómez
This study was undertaken to analyse the activated sludge of a membrane bioreactor (MBR), the behaviour of extracellular polymeric substances (EPS) and soluble microbial products (SMP) as well as their biopolymers composition, in the activated sludge of a membrane bioreactor (MBR) and their influence on membrane fouling were analysed. For the experiment an experimental fullscale MBR working with real urban wastewater at high hydraulic retention time with a variable sludge-retention time (SRT) was used. The MBR system worked in denitrification/nitrification conformation at a constant flow rate (Q = 0...
September 14, 2017: Journal of Environmental Science and Health. Part A, Toxic/hazardous Substances & Environmental Engineering
Xiaoliang Jiang, Yujing Wu, Guihua Liu, Wenzhi Liu, Bei Lu
Ammonia-oxidizing archaea (AOA) and bacteria (AOB) play important roles in regulating the nitrification process in lake ecosystems. However, the relative effects of climate, catchment land use and local conditions on the sediment ammonia-oxidizing communities in lakes remain unclear. In this study, the diversity and abundance of AOA and AOB communities were investigated in ten Yangtze lakes by polymerase chain reaction (PCR), clone library and quantitative PCR techniques. The results showed that the abundances of both AOA and AOB in bare sediments were considerably but not significantly higher than those in vegetated sediments...
September 13, 2017: AMB Express
I Santín, M Barbu, C Pedret, R Vilanova
The present paper focused on reducing greenhouse gases emissions in wastewater treatment plants operation by application of suitable control strategies. Specifically, the objective is to reduce nitrous oxide emissions during the nitrification process. Incomplete nitrification in the aerobic tanks can lead to an accumulation of nitrite that triggers the nitrous oxide emissions. In order to avoid the peaks of nitrous oxide emissions, this paper proposes a cascade control configuration by manipulating the dissolved oxygen set-points in the aerobic tanks...
August 28, 2017: Water Research
Xinbo Zhang, Zi Song, Wenshan Guo, Yanmin Lu, Li Qi, Haitao Wen, Huu Hao Ngo
This study aims to investigate the behavior of nitrogen removal in an aerobic sponge based moving bed biofilm reactor by evaluating nitrification and denitrification rates of sponge biocarriers from three aerobic moving bed biofilm reactors (MBBRs) with filling ratios of 10% (R-10), 20% (R-20) and 30% (R-30). Results showed that the highest removal efficiencies of total nitrogen in three reactors were 84.5% (R-10), 93.6% (R-20) and 95.3% (R-30). Correspondingly, simultaneous nitrification and denitrification rate (SND) was 90...
August 19, 2017: Bioresource Technology
Co Thi Kinh, Shohei Riya, Masaaki Hosomi, Akihiko Terada
A membrane-aerated biofilm reactor (MABR) provides a counter-current substrate diffusion geometry in which oxygen is supplied from a gas-permeable membrane on which a biofilm is grown. This study hypothesized that an MABR would mitigate NO and N2O emissions compared with those from a conventional biofilm reactor (CBR). Two laboratory-scale reactors, representing an MABR and CBR, were operated by feeding synthetic industrial wastewater. The surficial nitrogen removal rate for the MABR [4.51±0.52g-N/(m(2)day)] was higher than that for the CBR [3...
August 12, 2017: Bioresource Technology
A M Rada-Ariza, C M Lopez-Vazquez, N P van der Steen, P N L Lens
Ammonium removal from artificial wastewater by microalgal-bacterial consortia in a flat-panel reactor (FPR1) was compared with a microalgae-only flat-panel reactor (FPR2). The microalgal-bacterial consortia removed ammonium at higher rates (100±18mgNH4(+)-NL(-1)d(-1)) than the microalgae (44±16mgNH4(+)-NL(-1)d(-1)), after the system achieved a stable performance at a 2days hydraulic retention time. Nitrifiers present in the microalgae-bacteria consortia increased the ammonium removal: the ammonium removal rate by nitrifiers and by algae in FPR1 was, respectively, 50(±18) and 49(±22)mgNH4(+)-NL(-1)d(-1)...
August 13, 2017: Bioresource Technology
Brett L Mellbye, Eva Spieck, Peter J Bottomley, Luis A Sayavedra-Soto
The genomes of many bacteria that participate in nitrogen cycling through the process of nitrification contain putative genes associated with acyl-homoserine lactone (AHL) quorum sensing (QS). AHL QS or bacterial cell-cell signaling is a method of bacterial communication and gene regulation and may be involved in nitrogen oxide fluxes or other important phenotypes in nitrifying bacteria. Here, we carried out a broad survey of AHL production in nitrifying bacteria in three steps. First, we analyzed the evolutionary history of AHL synthase and AHL receptor homologs in sequenced genomes and metagenomes of nitrifying bacteria to identify AHL synthase homologs in ammonia-oxidizing bacteria (AOB) of the genera Nitrosospira and nitrite-oxidizing bacteria (NOB) of the genera Nitrococcus, Nitrobacter, and Nitrospira Next, we screened cultures of both AOB and NOB cultures with uncharacterized AHL synthase genes and AHL synthase-negative nitrifiers by bioassay...
September 8, 2017: Applied and Environmental Microbiology
J Tolksdorf, P Cornel
The infrastructure approach SEMIZENTRAL has been developed for fast growing cities, to meet their challenges regarding water supply as well as biowaste and wastewater treatment. The world's first full-scale SEMIZENTRAL Resource Recovery Center (RRC) has been implemented in Qingdao (PR China). Greywater (GW) and blackwater (BW) are collected and treated separately. Measurement of influent concentrations differ significantly from the design values. Thus, the operation strategy for the RRC had to be adapted. Amongst other reasons, the changed influent characteristic was caused by misconnections of GW and BW sewers...
September 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Jinjin Liu, Yue Yuan, Baikun Li, Qiong Zhang, Lei Wu, Xiyao Li, Yongzhen Peng
An anaerobic-aerobic-anoxic sequencing batch reactor (AOA-SBR) using sludge fermentation products as carbon source was developed to enhance nitrogen and phosphorus removal in municipal wastewater with low C/N ratio (<4) and reduce sludge production. The AOA-SBR achieved simultaneous partial nitrification and denitrification (SND), aerobic phosphorus uptake and anoxic denitrification through the real-time control and the addition of sludge fermentation products. The average removal efficiencies of total nitrogen (TN), phosphorus (PO4(3-)-P) and chemical oxygen demand (COD) after 145-day operation were 88...
November 2017: Bioresource Technology
Changhua Fan, Bo Li, Zhengqin Xiong
Nitrification inhibitors, a promising tool for reducing nitrous oxide (N2O) losses and promoting nitrogen use efficiency by slowing nitrification, have gained extensive attention worldwide. However, there have been few attempts to explore the broad responses of multiple reactive gaseous nitrogen emissions of N2O, nitric oxide (NO) and ammonia (NH3) and vegetable yield to nitrification inhibitor applications across intensive vegetable soils in China. A greenhouse pot experiment with five consecutive vegetable crops was performed to assess the efficacies of two nitrification inhibitors, namely, nitrapyrin and dicyandiamide on reactive gaseous nitrogen emissions, vegetable yield and reactive gaseous nitrogen intensity in four typical vegetable soils representing the intensive vegetable cropping systems across mainland China: an Acrisol from Hunan Province, an Anthrosol from Shanxi Province, a Cambisol from Shandong Province and a Phaeozem from Heilongjiang Province...
August 30, 2017: Science of the Total Environment
Xu Yan, Jiaxi Zheng, Yunping Han, Jianwei Liu, Jianhui Sun
The problem of producing strong greenhouse gas of nitrous oxide (N2O) from biological nitrogen removal (BNR) process in wastewater treatment plants (WWTP) has elicited great concern from various sectors. In this study, three laboratory-scale wastewater treatment systems, with influent C/N ratios of 3.4, 5.4, and 7.5, were set up to study the effect of influent C/N ratio on N2O generation in anaerobic/anoxic/oxic (A(2)O) process. Results showed, with the increased influent C/N ratio, N2O generation from both nitrification and denitrification process was decreased, and the N2O-N conversion ratio of the process was obviously reduced from 2...
September 1, 2017: Environmental Science and Pollution Research International
Féline L Assémien, Thomas Pommier, Jean T Gonnety, Jonathan Gervaix, Xavier Le Roux
The moist savanna zone covers 0.5 × 10(6) km(2) in West Africa and is characterized by very low soil N levels limiting primary production, but the ecology of nitrifiers in these (agro)ecosystems is largely unknown. We compared the effects of six agricultural practices on nitrifier activity, abundance and diversity at nine sites in central Ivory Coast. Treatments, including repeated fertilization with ammonium and urea, had no effect on nitrification and crop N status after 3 to 5 crop cycles. Nitrification was actually higher at low than medium ammonium level...
August 31, 2017: Scientific Reports
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