Nitritation of real sewage: start-up and maintenance by the side-stream heat-shock treatment

2019 ◽  
Vol 79 (4) ◽  
pp. 753-758 ◽  
Author(s):  
Jianfei Chen ◽  
Shujun Zhang ◽  
Xiaoyu Han ◽  
Liang Zhang ◽  
Yongzhen Peng
Keyword(s):  
Heat Shock ◽  
Accumulation Rate ◽  
Batch Reactor ◽  
Shock Treatment ◽  
Nitrite Accumulation ◽  
Heat Shock Treatment ◽  
Term Operation ◽  
Side Stream ◽  
Start Up

Abstract In this study, the side-stream heat-shock treatment was used to start up and maintain the nitritation of real sewage. Complete nitrification was obtained when the real sewage was treated in a sequencing batch reactor (SBR). Then, about 50% of the mixed sludge was collected from the SBR and treated with the heat-shock treatment at 60 °C for 40 min in another reactor every 2 weeks. After providing the heat-shock treatment for four times, the effluent nitrate in the SBR gradually decreased from 22.5 to 3.2 mg/L, while the nitrite accumulation rate increased from 4.4% to 81.8%, indicating a successful start-up of nitritation. Further, the sewage nitritation was stable with the regular side-steam heat-shock treatment for 91 days, and the ammonium removal efficiency of 80.6% and nitrite accumulation rate of 91.2% were achieved. This study suggests that the side-stream heat-shock treatment could be used to start up sewage nitritation and maintain stability for a long-term operation.

Study on Achievement and Temperature Influence of Shortcut Nitrification in Sequencing Biofilm Batch Reactor

2014 ◽  
Vol 955-959 ◽  
pp. 3389-3392
Author(s):  
Li Cheng Zhang ◽  
Wei Dang ◽  
Jie Li ◽  
Jun Sui
Keyword(s):  
Accumulation Rate ◽  
Batch Reactor ◽  
Biofilm Reactor ◽  
Nitrite Accumulation ◽  
Ammonia Oxidizing Bacteria ◽  
Temperature Influence ◽  
Intermittent Aeration ◽  
Urban Sewage ◽  
Sequencing Batch Biofilm Reactor ◽  
Start Up

The intermittent aeration strategy was applied to the sequencing batch biofilm reactor (SBBR) for the enhanced treatment of urban sewage. Ammonia oxidizing bacteria was cultivated by inoculation. After 25 days cultivation shortcut nitrification was successfully achieved and nitrite accumulation rate could be up to 93%. In the start-up phase of shortcut nitrification, intermittent aeration could increase production of nitrite and promote the enrichment of ammonia oxidizing bacteria. It was concluded that temperature could affect nitrite accumulation. When temperature is in 25~35°C, the nitrite accumulation rate could be up to 90%.

Partial Nitrification to Nitrite with Real-Time Aeration Duration Control in an SBR Treating Domestic Wastewater

2011 ◽  
Vol 356-360 ◽  
pp. 1046-1049 ◽  
Author(s):  
Yu Chen ◽  
Jun Li ◽  
C .W Wang ◽  
X.F Zhao ◽  
B.H Zhao
Keyword(s):  
Real Time ◽  
Batch Reactor ◽  
Domestic Wastewater ◽  
Partial Nitrification ◽  
Nitrite Accumulation ◽  
Ammonia Oxidizing Bacteria ◽  
Term Operation ◽  
Nitrite Oxidizing Bacteria ◽  
Low Strength

Sustainable partial nitrification to nitrite has been proven difficult in treating low strength nitrogenous wastewater. Real-time aeration duration control was used to achieve efficient partial nitrification to nitrite in a sequencing batch reactor (SBR) to treat low strength domestic wastewater. Above 95% nitrite accumulation ratio was maintained for long-term operation at normal condition. Partial nitrification established by controlling aeration duration showed good performance and robustness even though some time encountering long-term extended aeration. Process control enhanced the successful accumulation of ammonia oxidizing bacteria (AOB) and washout of nitrite oxidizing bacteria (NOB).

scholarly journals Rapid cultivation and stability of autotrophic nitrifying granular sludge

2020 ◽  
Vol 81 (2) ◽  
pp. 309-320 ◽  
Author(s):  
Linan Zhang ◽  
Bei Long ◽  
Yuanyuan Cheng ◽  
Junfeng Wu ◽  
Binchao Zhang ◽  
...  
Keyword(s):  
Heterotrophic Bacteria ◽  
Accumulation Rate ◽  
Removal Rate ◽  
Granular Sludge ◽  
Ammonia Nitrogen ◽  
Nitrifying Bacteria ◽  
Structure Stability ◽  
Nitrite Accumulation ◽  
Term Operation

Abstract Autotrophic nitrifying granular sludge (ANGS) was cultivated by gradually decreasing the influent organics and adding exogenous nitrifying bacteria. Under the strategy, ANGS was domesticated within 36 days. Stability of the seed heterotrophic granules decreased significantly during conversion of organic wastewater to inorganic ammonia wastewater. Obvious granular breakage was observed during these days. However, the granular debris still had good settlement performance. With microbes gradually acclimated to the new environment, the debris provided a large number of carriers for the attached growth of the exogenous nitrifying bacteria, and they replaced the heterotrophic bacteria and became the dominant species. The domesticated ANGS showed good nitrification performance during the 37th to the 183rd day (ammonia nitrogen load between 0.28 and 0.29 kg/m3 · d). The removal rate of ammonia nitrogen was usually more than 95%, and nitrite accumulation rate was always larger than 50%. However, nitrification ability was gradually lost with the increase of the ammonia nitrogen load (0.3–0.64 kg/m3 · d) from the 184th day, and it almost approached the influent ammonia nitrogen at the 269th day. Interestingly, good structure stability of the ANGS was maintained during long-term operation, and the ANGS became smoother and denser at the end of the experiment.

Abstract 19822: Arterial Calcification Can Be Inhibited via Stress Protein Induction Through a PPAR-dependent Pathway

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Kenneth Lim ◽  
Jen Xu ◽  
E-Jay Kao ◽  
Tianqing Kong ◽  
Tzongshi Lu
Keyword(s):  
Heat Shock ◽  
Shock Treatment ◽  
Arterial Calcification ◽  
Protective Effects ◽  
Heat Shock Treatment ◽  
Fatty Acid Binding ◽  
Human Arteries ◽  
Molecular Chaperon

Introduction: Cardiovascular disease occurs prematurely in chronic inflammatory conditions such as Chronic Kidney Disease (CKD) and unfortunately, remains the leading cause of death in these patients. Vascular calcification (VC) is a significant contributor to cardiovascular mortality in CKD patients with the sequela of arterial hardening, congestive heart failure and sudden cardiac death. We recently reported that heat shock protein 72 (HSP72) when inducted, can inhibit the development of VC. Hypothesis: We hypothesize that HSP72 exerts its vasculo-protective effects by functioning as a molecular chaperon for peroxisome proliferator-activated receptor γ (PPARγ). Methods: We developed an in vitro long-term calcification model using HA-SMCs treated with calcification medium (CM) containing 5mM CaCl2 and 5mM β-glycerophosphate for 21 days. Cells were subjected to heat shock treatment at 43°C for 30 minutes daily to induce HSP72. Calcification was assessed qualitatively by alizarin red staining and quantitatively by the arsenazo III method. Results: Our results show that inducible HSP72 is significantly expressed following heat shock treatment in HA-SMCs. Induction of HSP72 inhibited the development of VC in our long-term calcification model and these effects were abolished by HSP72 siRNA, in vitro. We next showed that HSP72 formed a protein-protein complex with PPARγ by co-immunoprecipitation. Expression of both these proteins was down-regulated in calcific HA-SMCs and their gene expression was down regulated in atherosclerotic human arteries. Furthermore, we found that the PPARγ inhibitor, FABP4 (fatty acid binding protein-4) which function as an atherosclerosis promoter was up-regulated in calcified human arteries. Lastly, induction of HSP72 restored expression of the HSP72-PPARγ complex and inhibited upregulation of FABP4 with reduction in calcification in our in vitro calcification model. These vasculo-protective effects were abolished by HSP72 siRNA. Conclusion: HSP72 is a powerful inhibitor of VC and exerts its vasculo-protective effects by functioning as a molecular chaperon to stabilize PPARγ and regulate the PPARγ-FABP4 pathway. We suggest treatment strategies involving induction of HSP72 as a new approach to inhibit VC.

Applying real-time control for realization and stabilization of shortcut nitrification-denitrification in domestic water treatment

2009 ◽  
Vol 59 (4) ◽  
pp. 787-796 ◽  
Author(s):  
Tao Ma ◽  
Chaocheng Zhao ◽  
Yongzhen Peng ◽  
Xiuhong Liu ◽  
Li Zhou
Keyword(s):  
Real Time ◽  
Accumulation Rate ◽  
Batch Reactor ◽  
Operation Mode ◽  
Domestic Wastewater ◽  
Nitrite Accumulation ◽  
Real Time Control ◽  
Domestic Water ◽  
Time Control

A sequencing batch reactor (SBR) was used to treat real domestic wastewater focusing on the achievement, maintenance and the feasibility of nitrite accumulation under real-time control. Keeping temperature, MLSS and dissolved oxygen (DO) in reactor at 28±1°C, 2,400 mg/L and higher than 2.0 mg/L respectively, shortcut nitrification-denitrification was successfully achieved after about two months. But the sudden raise of ammonia loading rate (ALR) caused deterioration of nitrite accumulation and occurrence of filamentous sludge bulking. These undesirable situations could be solved by pre-anaerobic operation mode. If applying long-term real-time control strategy to supervise the nitrification course, the sludge population optimization and high nitrite accumulation rate at different DO levels could be achieved. The strategy taking pH and aeration quantity as control parameters for nitrification in SBR was put forward under invariable DO conditions in this paper. By maintaining low DO level (below 1.0 mg/L), the shortcut nitrification-denitrification could be achieved in the same reactor with simultaneous nitrification and denitrification (SND), through which the removed nitrogen accounted for 49.12% to 66.81% of total nitrogen (TN) in influent at the end of shortcut nitrification.

scholarly journals Rapid Start-Up of the Aerobic Granular Reactor under Low Temperature and the Nutriment Removal Performance of Granules with Different Particle Sizes

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3590
Author(s):  
Dongbo Liang ◽  
Jun Li ◽  
Zhaoming Zheng ◽  
Jing Zhang ◽  
Yaodong Wu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Accumulation Rate ◽  
Removal Rate ◽  
Batch Reactor ◽  
Synthetic Wastewater ◽  
Aerobic Granular Sludge ◽  
Nitrite Accumulation ◽  
Stable Operation ◽  
N Removal ◽  
Start Up

The start-up of the aerobic granular sludge (AGS) process under low temperature is challenging. In this study, the sequencing batch reactor (SBR) was fed with synthetic wastewater and the temperature was controlled at 15 ℃. The main components in the synthetic wastewater were sodium acetate and ammonium chloride. The influent chemical oxygen demand (COD) and NH4+-N concentrations were 300 and 60 mg/L, respectively. The AGS was successfully cultivated in 60 days by gradually shortening the settling time. During the stable operation stage (61–100 d), the average effluent COD, NH4+-N, NO2−-N, and NO3−-N concentrations were 47.2, 1.0, 47.2, and 5.1 mg/L, respectively. Meanwhile, the nitrite accumulation rate (NAR) reached 90.6%. Batch test showed that the smaller AGS had higher NH4+-N removal rate while the larger AGS performed higher NAR. The NH4+-N removal rates of R1 (1.0–2.0 mm), R2 (2.0–3.0 mm), and R3 (>3 mm) granules were 0.85, 0.61, and 0.45 g N/(kg VSS·h), respectively. Meanwhile, the NAR of R1, R2, and R3 were 36.2%, 77.2%, and 94.9%, respectively. The obtained results could provide important guidance for the cultivation of AGS in low-temperature wastewater treatment.

Heat-induced triploids in Brycon amazonicus: a strategic fish species for aquaculture and conservation

Zygote ◽  
2021 ◽  
pp. 1-5
Author(s):  
Nivaldo Ferreira do Nascimento ◽  
Rafaela Manchin Bertolini ◽  
Lucia Soares Lopez ◽  
Laura Satiko Okada Nakaghi ◽  
Paulo Sérgio Monzani ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Heat Shock ◽  
Early Development ◽  
Fish Species ◽  
Survival Rates ◽  
Shock Treatment ◽  
Hatching Rate ◽  
Heat Shock Treatment ◽  
Control Survival ◽  
Ploidy Status

Summary Triploidization plays an important role in aquaculture and surrogate technologies. In this study, we induced triploidy in the matrinxã fish (Brycon amazonicus) using a heat-shock technique. Embryos at 2 min post fertilization (mpf) were heat shocked at 38°C, 40°C, or 42°C for 2 min. Untreated, intact embryos were used as a control. Survival rates during early development were monitored and ploidy status was confirmed using flow cytometry and nuclear diameter analysis of erythrocytes. The hatching rate reduced with heat-shock treatment, and heat-shock treatments at 42°C resulted in no hatching events. Optimal results were obtained at 40°C with 95% of larvae exhibiting triploidy. Therefore, we report that heat-shock treatments of embryos (2 mpf) at 40°C for 2 min is an effective way to induce triploid individuals in B. amazonicus.

scholarly journals Characterization of the thermotolerant cell. I. Effects on protein synthesis activity and the regulation of heat-shock protein 70 expression.

1988 ◽  
Vol 106 (4) ◽  
pp. 1105-1116 ◽  
Author(s):  
L A Mizzen ◽  
W J Welch
Keyword(s):  
Protein Synthesis ◽  
Heat Shock ◽  
Stress Proteins ◽  
Stress Protein ◽  
Shock Treatment ◽  
Heat Shock Treatment ◽  
Normal Medium ◽  
Growth Environment ◽  
Mammalian Cell Lines ◽  
C 30

Exposure of mammalian cells to a nonlethal heat-shock treatment, followed by a recovery period at 37 degrees C, results in increased cell survival after a subsequent and otherwise lethal heat-shock treatment. Here we characterize this phenomenon, termed acquired thermotolerance, at the level of translation. In a number of different mammalian cell lines given a severe 45 degrees C/30-min shock and then returned to 37 degrees C, protein synthesis was completely inhibited for as long as 5 h. Upon resumption of translational activity, there was a marked induction of heat-shock (or stress) protein synthesis, which continued for several hours. In contrast, cells first made thermotolerant (by a pretreatment consisting of a 43 degrees C/1.5-h shock and further recovery at 37 degrees C) and then presented with the 45 degrees C/30-min shock exhibited considerably less translational inhibition and an overall reduction in the amount of subsequent stress protein synthesis. The acquisition and duration of such "translational tolerance" was correlated with the expression, accumulation, and relative half-lives of the major stress proteins of 72 and 73 kD. Other agents that induce the synthesis of the stress proteins, such as sodium arsenite, similarly resulted in the acquisition of translational tolerance. The probable role of the stress proteins in the acquisition of translational tolerance was further indicated by the inability of the amino acid analogue, L-azetidine 2-carboxylic acid, an inducer of nonfunctional stress proteins, to render cells translationally tolerant. If, however, analogue-treated cells were allowed to recover in normal medium, and hence produce functional stress proteins, full translational tolerance was observed. Finally, we present data indicating that the 72- and 73-kD stress proteins, in contrast to the other major stress proteins (of 110, 90, and 28 kD), are subject to strict regulation in the stressed cell. Quantitation of 72- and 73-kD synthesis after heat-shock treatment under a number of conditions revealed that "titration" of 72/73-kD synthesis in response to stress may represent a mechanism by which the cell monitors its local growth environment.

scholarly journals DNA damage and heat shock dually regulate genes in Saccharomyces cerevisiae.

1986 ◽  
Vol 6 (1) ◽  
pp. 90-96 ◽  
Author(s):  
T McClanahan ◽  
K McEntee
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Damage ◽  
Heat Shock ◽  
Shock Treatment ◽  
Northern Hybridization ◽  
Heat Shock Treatment ◽  
Base Pairs ◽  
S1 Nuclease ◽  
Hsp70 Family ◽  
Transcriptional Start Sites

Two Saccharomyces cerevisiae genes isolated in a differential hybridization screening for DNA damage regulation (DDR genes) were also transcriptionally regulated by heat shock treatment. A 0.45-kilobase transcript homologous to the DDRA2 gene and a 1.25-kilobase transcript homologous to the DDR48 gene accumulated after exposure of cells to 4-nitroquinoline-1-oxide (NQO; 1 to 1.5 microgram/ml) or brief heat shock (20 min at 37 degrees C). The DDRA2 transcript, which was undetectable in untreated cells, was induced to high levels by these treatments, and the DDR48 transcript increased more than 10-fold as demonstrated by Northern hybridization analysis. Two findings argue that dual regulation of stress-responsive genes is not common in S. cerevisiae. First, two members of the heat shock-inducible hsp70 family of S. cerevisiae, YG100 and YG102, were not induced by exposure to NQO. Second, at least one other DNA-damage-inducible gene, DIN1, was not regulated by heat shock treatment. We examined the structure of the induced RNA homologous to DDRA2 after heat shock and NQO treatments by S1 nuclease protection experiments. Our results demonstrated that the DDRA2 transcript initiates equally frequently at two sites separated by 5 base pairs. Both transcriptional start sites were utilized when cells were exposed to either NQO or heat shock treatment. These results indicate that DDRA2 and DDR48 are members of a unique dually regulated stress-responsive family of genes in S. cerevisiae.

Repetitive Dictyostelium heat-shock promotor functions in Saccharomyces cerevisiae

1984 ◽  
Vol 4 (4) ◽  
pp. 591-598
Author(s):  
J Cappello ◽  
C Zuker ◽  
H F Lodish
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Heat Shock ◽  
Nucleotide Sequence ◽  
Dna Sequence ◽  
Base Pair ◽  
Shock Treatment ◽  
Yeast Cells ◽  
Genomic Segment ◽  
Heat Shock Treatment ◽  
Shock Response

The Dictyostelium genome contains 40 copies of a 4.7-kilobase repetitive and apparently transposable DNA sequence (DIRS-1) and about 250 smaller elements that appear to be deletions or rearrangements of DIRS-1. Transcripts of these sequences are induced during differentiation and also by heat shock treatment of growing cells. We showed that one such cloned element, pB41.6 (2.5 kilobases) contains a nucleotide sequence identical to the Drosophila consensus heat shock promotor. To test whether this sequence might indeed control the expression of DIRS-1-related RNAs, we have cloned this genomic segment into yeast cells. In yeast cells, 41.6 directs synthesis of a 1.7-kilobase RNA that is induced at least 10-fold by heat shock. Transcription initiates at about 124 bases 3' of the putative promotor sequence and terminates within the 41.6 insert. A 381-base-pair subclone that contains the putative promotor sequence is sufficient to induce the heat shock response of 41.6 in yeast cells.

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