On Why Less Is More in Climate Fiction Ismail, Sherif H
Interdisciplinary studies in literature and environment,
05/2024, Letnik:
31, Številka:
2
Journal Article
•Anammox baffled reactor (AnBR) revealed moderate start-up period of 53 days.•Anammox sludge characteristics have statistically robust relationships.•ANN effectively simulated AnBR with R2 and MSE of ...0.99 and 0.002, respectively.•AnBR at NLR of 4.04 kg-N/m3/day exhibited net present value of $48100.9.
Anammox baffled reactor (AnBR) had a moderate start-up period of 53 days. Interestingly, tangled relationships between key parameters affecting anammox performance were observed, i.e., polynomial function for nitrogen loading rate (NLR) with extracellular polymeric substances (EPS), linear relationships between EPS with granules diameter, granules diameter with settling velocity, and settling velocity with biomass concentration. The correlation coefficients (R2) were 0.97, 0.84, 0.86, and 0.88, respectively. Furthermore, a multi-layered feed forward artificial neural network (ANN) was utilized for simulating and predicting the performance of AnBR. An ANN structure of two hidden layers with four neurons at 1st layer and eight neurons at 2nd layer achieved the best goodness of fit with the minimum mean squared error (MSE) and maximum R2 of 0.002 and 0.99, respectively. Additionally, economic assessment stated that using AnBR at NLR of 4.04 ± 0.10 kg-N/m3/day achieved the maximum net present value of $48100.9.
With the publication of The Death of Jesus (2019), following The Childhood of Jesus (2013) and The Schooldays of Jesus (2016), J. M. Coetzee's Jesus novels are a completed trilogy. Baffling to ...reviewers and critics, attempts have been made to situate the Jesus novels in Coetzee's previous oeuvre, and to establish continuity in the author's literary thinking and style. This essay highlights Coetzee's identification with Jesus in Summertime (2009), the last instalment in the author's autobiographical trilogy, where an author named John Coetzee is already dead. The essay reads Summertime as an elaborate 'posthumous' confessional design meant by Coetzee to evade the obstacles of secular confession and to enable (fictional) redemption and absolution. Coetzee's invocation of Jesus as 'a guide' in turn serves to code authorial death and resurrection as a final act of sacrifice and taking responsibility. Thus providing a sense of finality to Coetzee's autobiographical trilogy, the confessional design of Summertime prepares for a new phase in the author's writing, in the name of Jesus.
Direct sewage discharge could cause copious numbers of serious and irreversible harm to the environment. This study investigated the impacts of treated and raw sewage on the river ecosystem. Through ...our analysis, sewage carried various nutrients into the river, leading to changes in the microbial community in the river and reducing the diversity and richness of bacteria. The relative abundances of Hydrogenophaga, Thauera, Planctomyces, Zoogloea, and Pseudomonas boosted from 0.25, 0.01, 0.00, 0.05, and 0.08% to 3.33, 3.43, 0.02, 6.28, and 2.69%, before and after raw sewage discharge, respectively. The gene abundance of pathogenic bacteria significantly increased after raw sewage discharge. For instance, the gene abundance of Vibrio, Helicobacter, Tuberculosis, and Staphylococcus augmented from 4055, 3797, 13,545, 33 reads at Site-1 to 23,556, 13,163, 19,887, 734 reads at Site-2, respectively. In addition, according to the redundancy analysis (RDA), the infectious pathogens were positively related to the environmental parameters, in which COD showed the highest positive correlation with Mycobacterium tuberculosis. Additionally, river self-purification may contribute to improving water quality and reducing pathogenicity. The outcomes of this study showed that direct discharge brought pathogens and changed microbial community structure of the river.
Fenton process for pre-treatment of hazardous landfill leachate (HLL) was investigated. Total, particulate and soluble chemical oxygen demand (CODt, CODp and CODs) removal efficiency amounted to 67%, ...47% and 64%, respectively, at pH value of 3.5, molar ratio (H2O2/Fe(2+)) of 5, H2O2 dosage of 25 ml/L and contact time of 15 min. Various treatment scenarios were attempted and focused on studying the effect of pre-catalytic oxidation process on the performance of up-flow anaerobic sludge blanket (UASB), UASB/down-flow hanging sponge (DHS) and DHS system. The results obtained indicated that pre-catalytic oxidation process improved the CODt removal efficiency in the UASB reactor by a value of 51.4%. Overall removal efficiencies of CODt, CODs and CODp were 80 ± 6%, 80 ± 7% and 78 ± 16% for UASB/DHS treating pre-catalytic oxidation effluent, respectively. The removal efficiencies of CODt, CODs and CODp were, respectively, decreased to 54 ± 2%, 49 ± 2% and 71 ± 16% for UASB/DHS system without pre-treatment. However, the results for the combined process (UASB/DHS) system is almost similar to those obtained for UASB reactor treating pre-catalytic oxidation effluent. The DHS system achieved average removal efficiencies of 52 ± 4% for CODt, 51 ± 4% for CODs and 52 ± 15% for CODp. A higher COD fractions removal was obtained when HLL was pre-treated by Fenton reagent. The combined processes provided a removal efficiency of 85 ± 1% for CODt, 85 ± 1% for CODs and 83 ± 8% for CODp. The DHS system is not only effective for organics degradation but also for ammonia oxidation. Almost complete ammonia (NH4-N) removal (92 ± 3.6%) was occurred and the nitrate production amounted to 37 ± 6 mg/L in the treated effluent. This study strongly recommends applying Fenton process followed by DHS system for treatment of HLL.
Eukaryotic 60S ribosomal subunits are comprised of three rRNAs and ∼50 ribosomal proteins. The initial steps of their formation take place in the nucleolus, but, owing to a lack of structural ...information, this process is poorly understood. Using cryo-EM, we solved structures of early 60S biogenesis intermediates at 3.3 Å to 4.5 Å resolution, thereby providing insights into their sequential folding and assembly pathway. Besides revealing distinct immature rRNA conformations, we map 25 assembly factors in six different assembly states. Notably, the Nsa1-Rrp1-Rpf1-Mak16 module stabilizes the solvent side of the 60S subunit, and the Erb1-Ytm1-Nop7 complex organizes and connects through Erb1’s meandering N-terminal extension, eight assembly factors, three ribosomal proteins, and three 25S rRNA domains. Our structural snapshots reveal the order of integration and compaction of the six major 60S domains within early nucleolar 60S particles developing stepwise from the solvent side around the exit tunnel to the central protuberance.
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•Structures of five nucleolar pre-60S intermediates by cryo-EM•Assembly factors Nsa1, Mak16, Rpf1, and Rrp1 form a module at the solvent side•Erb1 acts as a central coordinator at the intersubunit side•A sequential assembly pathway follows after the 5′ to 3′ circular formation of pre-rRNA
Cryo-EM analysis of the architecture of pre-60S ribosomes provides insights into the sequential events and intermediate states critical for ribosome assembly, as well as the functions of many associated factors.
Long-term exposure of anammox process to 1,4-dioxane was investigated using periodic anammox baffled reactor (PABR) under different 1,4-dioxane concentrations. The results generally indicated that ...PABR (composed of 4 compartments) has robust resistance to 10 mg-dioxane/L. The 1st compartment acted as a shield to protect subsequent compartments from 1,4-dioxane toxicity through secretion of high extracellular polymeric substance (EPS) of 152.9 mg/gVSS at 10 mg-dioxane/L. However, increasing 1,4-dioxane to 50 mg/L significantly inhibited anammox bacteria; e.g., ~ 93% of total nitrogen removal was lost within 14 days. The inhibition of anammox process at this dosage was most likely due to bacterial cell lysis, resulting in the decrease of EPS secretion and specific anammox activity (SAA) to 105.9 mg/gVSS and 0.04 mg N/gVSS/h, respectively, in the 1st compartment. However, anammox bacteria were successfully self-recovered within 41 days after the cease of 1,4-dioxane exposure. The identification of microbial compositions further emphasized the negative impacts of 1,4-dioxane on abundance of C. Brocadia among samples. Furthermore, the development of genus Planococcus in the 1st compartment, where removal of 1,4-dioxane was consistently observed, highlights its potential role as anoxic 1,4-dioxane degrader. Overall, long-term exposure to 1,4-dioxane should be controlled not exceeding 10 mg/L for a successful application.
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•Anammox bacteria revealed robust resistance for long-term exposure to 10 mg-dioxane/L•Most of N-removal was achieved in the first compartment of PABR•Process failure was noticed after 14 days of exposure to 50 mg-dioxane/L•Anammox process was self-recovered after 41 days of 1,4-dioxane non-exposure condition.•Planococcus shared microbial community with C. Brocadia due to 1,4-dioxane exposure
In this study, compartment-wise investigation of an anammox baffled reactor (AnBR) was performed. The AnBR achieved steady-state conditions after a start-up period of ∼50 days and achieved NH4 and ...NO2 conversion percentages of 88.5 and 99.3%, respectively. Examination of the nitrogen mass balance revealed that an AnBR with a two-compartment configuration was sufficient for nitrogen loading rates (NLRs) ranging from 0.125 to 1.975 kg N/m3/d and resulted in a nitrogen removal efficiency (NRE) of 86.7–93.7%. Higher NLRs (4.04–5.05 kg N/m3/d) required four compartments to achieve an NRE of 82.2–87.1%. Further, an overall NLR increase of up to 5.93 ± 0.23 kg N/m3/d resulted in complete AnBR failure. The maximum nitrogen removal rate was consistently recorded in the 1st compartment for all NLRs examined; as a result, this compartment exhibited the highest bacterial activity. Biomass concentration, specific anammox activity, extracellular polymeric substances, and average granule diameter in the 1st compartment with an overall NLR of 0.05 kg N/m3/d were estimated to be 11.2 gVSS/L, 0.03 mg N/gVSS/h, 84.3 mg/gVSS, and 0.65 mm, respectively. These values increased to 26.1 gVSS/L, 11.80 mg N/gVSS/h, 242.1 mg/gVSS, and 2.31 mm, respectively, when the overall NLR was incremented to 4.04 kg N/m3/d. However, a gradual reduction in bacterial activity was observed from the 1st to the 5th compartment. The microbial community analysis indicated that the dominant phyla in the 1st compartment (NLR of 0.252 kg N/m3/d) with the highest nitrogen removal were Chloroflexi (38.13%), Planctomycetes (22.62%), and Proteobacteria (14.75%).
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•Sufficient number of AnBR compartments for nitrogen removal varied depending on NLR.•High EPS and low PN/PS enhanced Anammox activity in the first compartment.•AnBR adapted-microbes dominated by Chloroflexi, Planctomycetes and Proteobacteria.•Behavior of nitrogen fractions in AnBR compartments was mathematically modeled.
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•Anammox bacteria revealed robust resistance to the toxicity to 200 mg/L 1,4-dioxane.•1,4-Dioxane inhibition to anammox process was found to be substrate dependent.•Inactivation of ...HDH enzyme is the main anammox inhibition mechanism by 1,4-dioxane.•Candidatus Brocadia was adversely affected by increasing 1,4-dioxane concentration.
Anammox process contaminated by 1,4-dioxane was evaluated using sets of batch experiments under different nitrogen loads and 1,4-dioxane concentrations. Toxicity of 1,4-dioxane to anammox consortia was negligible till the level of 200 mg-dioxane/L with a reduction in the total nitrogen (TN) removal efficiency, less than 8% at initial loads of <200 mgTN/L. However, 1,4-dioxane inhibition was also found to be substrate-dependent, where TN removal efficiency was declined by 19.3% at 500 mgTN/L and 200 mg-dioxane/L. The negative synergistic effect was exacerbated in the case of 500 mgTN/L and 2000 mg-dioxane/L, with the minimum TN removal efficiency of 24.1 ± 1.2%. Moreover, the impact of 1,4-dioxane on anammox activity was evaluated in terms of specific anammox activity (SAA), hydrazine dehydrogenase (HDH) activity, and extracellular polymeric substances (EPS). These parameters revealed a significant reduction when 1,4-dioxane surpassed 200 mg/L. Their lowest values of 0.90 ± 0.02 mgTN/gVSS/h (54.7% lower than control), 0.45 ± 0.03 µmol cytochrome-c reduced/min/mg protein (45.1% lower than control), and 74.8 ± 8.5 mg/gVSS (32.6% lower than control) were recorded when anammox bacteria were subjected to initial TN and 1,4-dioxane loads of 200 and 2000 mg/L, respectively. The inhibition mechanism of 1,4-dioxane on the anammox process was expected owing to HDH enzyme inactivation that led to a reduction in SAA and EPS secretion ability. Further, the 16S rRNA analysis revealed that the exposure to 1,4-dioxane caused a significant drop in the dominant anammox genus Candidatus Brocadia, along with a progression of denitrifying bacteria, particularly genus Limnobacter.
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