scholarly journals Start-up Strategies for Anaerobic Ammonia Oxidation (Anammox) in In-Situ Nitrogen Removal from Polluted Groundwater in Rare Earth Mining Areas

2021 ◽  
Vol 13 (8) ◽  
pp. 4591
Author(s):  
Shuanglei Huang ◽  
Daishe Wu
Keyword(s):  
Rare Earth ◽  
Low Temperature ◽  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Ex Situ ◽  
High Concentration ◽  
Low Concentration ◽  
Start Up ◽  
Anammox Activity

The tremendous input of ammonium and rare earth element (REE) ions released by the enormous consumption of (NH4)2SO4 in in situ leaching for ion-adsorption RE mining caused serious ground and surface water contamination. Anaerobic ammonium oxidation (anammox) was a sustainable in situ technology that can reduce this nitrogen pollution. In this research, in situ, semi in situ, and ex situ method of inoculation that included low-concentration (0.02 mg·L−1) and high-concentration (0.10 mg·L−1) lanthanum (La)(III) were adopted to explore effective start-up strategies for starting up anammox reactors seeded with activated sludge and anammox sludge. The reactors were refrigerated for 30 days at 4 °C to investigate the effects of La(III) during a period of low-temperature. The results showed that the in situ and semi in situ enrichment strategies with the addition of La(III) at a low-concentration La(III) addition (0.02 mg·L−1) reduced the length of time required to reactivate the sludge until it reached a state of stable anammox activity and high nitrogen removal efficiency by 60–71 days. The addition of La(III) promoted the formation of sludge floc with a compact structure that enabled it to resist the adverse effects of low temperature and so to maintain a high abundance of AnAOB and microbacterial community diversity of sludge during refrigeration period. The addition of La(III) at a high concentration caused the cellular percentage of AnAOB to decrease from 54.60 ± 6.19% to 17.35 ± 6.69% during the enrichment and reduced nitrogen removal efficiency to an unrecoverable level to post-refrigeration.

scholarly journals Nitrogen removal using an anammox membrane bioreactor at low temperature

2015 ◽  
Vol 72 (12) ◽  
pp. 2148-2153 ◽  
Author(s):  
Takanori Awata ◽  
Yumiko Goto ◽  
Tomonori Kindaichi ◽  
Noriatsu Ozaki ◽  
Akiyoshi Ohashi
Keyword(s):  
Low Temperature ◽  
Nitrogen Removal ◽  
Membrane Bioreactor ◽  
Membrane Bioreactors ◽  
Distinct Advantage ◽  
Anammox Bacteria ◽  
Short Term ◽  
Term Operation ◽  
Anammox Activity

Membrane bioreactors (MBRs) have the ability to completely retain biomass and are thus suitable for slowly growing anammox bacteria. In the present study, an anammox MBR was operated to investigate whether the anammox activity would remain stable at low temperature, without anammox biomass washout. The maximum nitrogen removal rates were 6.7 and 1.1 g-N L−1 day−1 at 35 °C and 15 °C, respectively. Fluorescence in situ hybridization and 16S rRNA-based phylogenetic analysis revealed no change in the predominant anammox species with temperature because of the complete retention of anammox biomass in the MBR. These results indicate that the predominant anammox bacteria in the MBR cannot adapt to a low temperature during short-term operation. Conversely, anammox activity recovered rapidly after restoring the temperature from the lower value to the optimal temperature (35 °C). The rapid recovery of anammox activity is a distinct advantage of using an MBR anammox reactor.

scholarly journals Micro-pressure swirl reactor (MPSR) for efficient COD and nitrogen removal of high-concentration wastewater

2020 ◽  
Vol 82 (9) ◽  
pp. 1795-1807 ◽  
Author(s):  
Dejun Bian ◽  
Zebing Nie ◽  
Fan Wang ◽  
Shengshu Ai ◽  
Suiyi Zhu ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Lower Cost ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Swirl Flow ◽  
High Concentration ◽  
Internal Circulation ◽  
Carbon And Nitrogen ◽  
Pressure Swirl

Abstract A micro-pressure swirl reactor (MPSR) was developed for carbon and nitrogen removal of wastewater, in which dissolved oxygen (DO) gradient and internal circulation could be created by setting the aerators along one side of the reactor, and micro-pressure could be realized by sealing most of the top cap and increasing the outlet water level. In this study, velocity and DO distribution in the reactor was measured, removal performance treating high-concentration wastewater was investigated, and the main functional microorganisms were analyzed. The experiment results indicated that there was stable swirl flow and spatial DO gradient in MPSR. Operated in sequencing batch reactor mode, distinct biological environments spatially and temporally were created. Under the average influent condition of chemical oxygen demand (COD) concentration of 2,884 mg/L and total nitrogen (TN) of 184 mg/L, COD removal efficiency and removal loading was 98% and 1.8 kgCOD/(m3·d) respectively, and TN removal efficiency and removal loading reached up to 90% and 0.11 kgTN/(m3·d) respectively. With efficient utilization of DO and simpler configuration for simultaneous nitrification and denitrification, the MPSR has the potential of treating high-concentration wastewater at lower cost.

scholarly journals Nitrogen removal from recycled landfill leachate by ex situ nitrification and in situ denitrification

2006 ◽  
Vol 26 (8) ◽  
pp. 838-845 ◽  
Author(s):  
P.J. He ◽  
L.M. Shao ◽  
H.D. Guo ◽  
G.J. Li ◽  
D.J. Lee
Keyword(s):  
Nitrogen Removal ◽  
Landfill Leachate ◽  
Ex Situ

scholarly journals Evaluation of a novel low-carbon to nitrogen- and temperature-tolerant simultaneously nitrifying–denitrifying bacterium and its use in the treatment of river water

RSC Advances ◽  
2018 ◽  
Vol 8 (48) ◽  
pp. 27417-27422 ◽  
Author(s):  
Peng Jin ◽  
Yinyan Chen ◽  
Zhanwang Zheng ◽  
Qizhen Du
Keyword(s):  
Low Temperature ◽  
River Water ◽  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Simultaneous Nitrification And Denitrification ◽  
Low Carbon ◽  
High Nitrogen ◽  
Denitrifying Bacterium ◽  
Nitrification And Denitrification

A novel simultaneous nitrification and denitrification Klebsiella sp. exhibits high nitrogen removal efficiency under low-temperature and low C/N wastewater.

scholarly journals Start-Up and Aeration Strategies for a Completely Autotrophic Nitrogen Removal Process in an SBR

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaoling Zhang ◽  
Fan Zhang ◽  
Yanhong Zhao ◽  
Zhengqun Li
Keyword(s):  
Removal Efficiency ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Tap Water ◽  
Granular Sludge ◽  
Anammox Bacteria ◽  
Intermittent Aeration ◽  
Start Up ◽  
Canon Process ◽  
Autotrophic Nitrogen Removal

The start-up and performance of the completely autotrophic nitrogen removal via nitrite (CANON) process were examined in a sequencing batch reactor (SBR) with intermittent aeration. Initially, partial nitrification was established, and then the DO concentration was lowered further, surplus water in the SBR with high nitrite was replaced with tap water, and continuous aeration mode was turned into intermittent aeration mode, while the removal of total nitrogen was still weak. However, the total nitrogen (TN) removal efficiency and nitrogen removal loading reached 83.07% and 0.422 kgN/(m3·d), respectively, 14 days after inoculating 0.15 g of CANON biofilm biomass into the SBR. The aggregates formed in SBR were the mixture of activated sludge and granular sludge; the volume ratio of floc and granular sludge was 7 : 3. DNA analysis showed that Planctomycetes-like anammox bacteria and Nitrosomonas-like aerobic ammonium oxidization bacteria were dominant bacteria in the reactor. The influence of aeration strategies on CANON process was investigated using batch tests. The result showed that the strategy of alternating aeration (1 h) and nonaeration (1 h) was optimum, which can obtain almost the same TN removal efficiency as continuous aeration while reducing the energy consumption, inhibiting the activity of NOB, and enhancing the activity of AAOB.

Start-Up and Cultivation of A2N Denitrifying Phosphorus and Nitrogen Removal System

2012 ◽  
Vol 610-613 ◽  
pp. 1454-1458
Author(s):  
Ming Fen Niu ◽  
Hong Jing Jiao ◽  
Li Xu ◽  
Yan Yu ◽  
Jian Wei
Keyword(s):  
Activated Sludge ◽  
Removal Efficiency ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Nitrogen And Phosphorus ◽  
Start Up ◽  
Two Phases ◽  
Removal System

A2N is two-sludge system, by using the method that first bringing up the cultivation of denitrifying phosphorus removing bacteria (DPB) and nitrification biofilm separately then connecting them, which can start up A2N system successfully. Nitrification biofilm was cultivated in a sequencing batch reactor (SBR). After 30 days, NH4+-N effluent concentration steadily stayed below 0.5mg·L-1.In another SBR, the activated sludge for the enrichment of DPB is from the anaerobic tank, which was firstly operated under anaerobic/aerobic (A/O) condition. After 20 days, PAOs was successfully enriched. Then, the activated sludge was conducted under anaerobic/anoxic/aerobic (A/A/O) condition, maintaining the anaerobic time, gradually increased anoxic time and induced aerobic time. After 30 days DPB was successfully enriched, two phases totally take 50 days. The removal efficiency of total nitrogen and phosphorus are above 85 % and 95 %, so that A2N system was started up successfully.

Electrical Evaluation of the Epi/Substrate Interface Quality after Different In-Situ and Ex-Situ Low-Temperature Pre-Epi Cleaning Methods

1998 ◽  
Vol 65-66 ◽  
pp. 237-240 ◽  
Author(s):  
Matty Caymax ◽  
S. Decoutere ◽  
Erika Röhr ◽  
W. Vandervorst ◽  
Marc M. Heyns ◽  
...  
Keyword(s):  
Low Temperature ◽  
Ex Situ ◽  
Interface Quality ◽  
Substrate Interface ◽  
Cleaning Methods

Nitrogen removal from landfill leachate via ex situ nitrification and sequential in situ denitrification

2009 ◽  
Vol 29 (4) ◽  
pp. 1347-1353 ◽  
Author(s):  
Qi Zhong ◽  
Daping Li ◽  
Yong Tao ◽  
Xiaomei Wang ◽  
Xiaohong He ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Landfill Leachate ◽  
Ex Situ

scholarly journals In Situ Persulfate Oxidation of 1,2,3-Trichloropropane in Groundwater of North China Plain

2019 ◽  
Vol 16 (15) ◽  
pp. 2752 ◽  
Author(s):  
Hui Li ◽  
Zhantao Han ◽  
Yong Qian ◽  
Xiangke Kong ◽  
Ping Wang
Keyword(s):  
Removal Efficiency ◽  
North China Plain ◽  
North China ◽  
Removal Rate ◽  
Chlorinated Hydrocarbons ◽  
Contaminated Site ◽  
High Concentration ◽  
Chlorinated Hydrocarbon ◽  
Persulfate Oxidation

In situ injection of Fe(II)-activated persulfate was carried out to oxidize chlorinated hydrocarbons and benzene, toluene, ethylbenzene, and xylene (BTEX) in groundwater in a contaminated site in North China Plain. To confirm the degradation of contaminants, an oxidant mixture of persulfate, ferrous sulfate, and citric acid was mixed with the main contaminants including 1,2,3-trichloropropane (TCP) and benzene before field demonstration. Then the mixed oxidant solution of 6 m3 was injected into an aquifer with two different depths of 8 and 15 m to oxidize a high concentration of TCP, other kinds of chlorinated hydrocarbons, and BTEX. In laboratory tests, the removal efficiency of TCP reached 61.4% in 24 h without other contaminants but the removal rate was decreased by the presence of benzene. Organic matter also reduced the TCP degradation rate and the removal efficiency was only 8.3% in 24 h. In the field test, as the solution was injected, the oxidation reaction occurred immediately, accompanied by a sharp increase of oxidation–reduction potential (ORP) and a decrease in pH. Though the concentration of pollutants increased due to the dissolution of non-aqueous phase liquid (NAPL) at the initial stage, BTEX could still be effectively degraded in subsequent time by persulfate in both aquifers, and their removal efficiency approached 100%. However, chlorinated hydrocarbon was relatively difficult to degrade, especially TCP, which had a relatively higher initial concentration, only had a removal efficiency of 30%–45% at different aquifers and monitoring wells. These finding are important for the development of injection technology for chlorinated hydrocarbon and BTEX contaminated site remediation.

Cleanroom Mats: An Investigation of Particle Removal

1996 ◽  
Vol 39 (4) ◽  
pp. 19-27
Author(s):  
W. Whyte ◽  
T. Shields ◽  
T. Prvan
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Removal Efficiency ◽  
Adhesive Strength ◽  
Particle Removal ◽  
High Concentration ◽  
Low Concentration

The variables that influence the particle removal efficiency of cleanroom mats were investigated. The removal efficiency was generally found to be greater if the mat was of a softer type, the particles smaller, the particle size distribution more homogeneous, the distance between the particles greater, and the adhesive strength of the mat surface greater. One application of a mat surface was sufficient to remove a low concentration of similarly sized particles from a surface but it could require up to four mat surfaces to remove a high concentration of heterogeneously sized particles. It was found with heterogeneously sized particles that larger particles were removed first, thus allowing access to the smaller particles which could then be removed. If the mat was soft, it allowed larger particles to sink into it and smaller particles than normal to be picked up.

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