Decrease In Total Organic Carbon Research Articles

The urgent need to reduce phosphorus discharges for sustainable mangrove wetland management

Phosphorus affects microbial metabolic activity, nitrogen and carbon cycling in mangrove sediment, but its influence on carbon stability and greenhouse gases emission remains unclear. This study compared greenhouse gases (CO2, N2O, and CH4) emissions from mangrove sediment receiving wastewater containing various phosphorus concentrations, and evaluated its long term effect on sediment carbon flux when phosphorus pollution is eliminated. Significant increases in greenhouse gases flux and decrease of total organic carbon and readily oxidizable organic carbon in the sediment were observed after phosphorus discharge. Specifically, the N2O flux was reduced significantly at high phosphorus levels while the CO2 flux and the microbial biomass organic carbon was increased. The copy numbers of ammonia oxidation (AOA-amoA, AOB-amoA) gene, denitrification (narG, nirK) gene and methanogenesis (mcrA) gene increased with the increasing phosphorus concentration. During the wastewater discharge period for 70 days, the global warming potential of sediment flux at high phosphorus discharge condition was more than 4 times that of the control group, and the loss of total organic carbon and readily oxidizable organic carbon was 4.66 % and 7.1 %, respectively. During the remediation period (71–101 days), the greenhouse gases flux decreased rapidly, ends up with a similar level of the control group. Our results indicate that using mangrove wetland for pollution minimization in the coastal aquaculture industry could increase greenhouse gases emisison significantly, it is therefore essential to reduce phosphorus discharges from various anthropogenic activities, and local authorities must set up more stringent discharge standards in the future.

Influence of the TiO2 crystalline phase on the performance of UVA/brookite/persulfate and UVA/anatase/persulfate systems for the degradation of isothiazolinones in aqueous matrices

The activation of persulfate (PS) under UVA irradiation by two TiO2 polymorphs (brookite and anatase) and titanate photocatalysts was evaluated for the simultaneous removal of the biocides methylisothiazolinone (MIT) and chloromethylisothiazolinone (CMIT), in ultrapure water and real sewage treatment plant water (SW). Titania and titanate samples were synthesized by a hydrothermal method and characterized by XRD, SEM, N2 adsorption-desorption isotherms and UV-Vis DR. The reactions were performed in individual (brookite, anatase, titanate and PS) and hybrid (titania/PS and titanate/PS) systems and compared to those with TiO2-P25 as reference. In ultrapure water, the combined brookite/PS system showed a higher performance for MIT and CMIT abatement and a stronger synergistic effect between titania and PS than found in anatase/PS and titanate/PS systems, indicating the higher effectiveness of the brookite phase for PS activation under UVA. The use of SW water revealed the strong inhibitory effect of matrix constituents in the individual brookite, anatase and PS systems, which exhibited a low performance. However, the kinetics of MIT/CMIT in SW were greatly enhanced in the hybrid TiO2/PS systems, especially with brookite, leading to an efficient degradation of both pollutants and the decrease of total organic carbon (TOC). The addition of chemical scavengers showed a similar reactivity of HO• towards both isothiazolinones whereas a preferential attack of SO4•− to MIT was observed, demonstrating the selective nature of SO4•−.

The impact of ammonifying microorganisms on the stabilization and carbon conversion of cow manure and wheat husk co-composting

Ammonifying microorganisms (Amm) play a crucial role in the global utilization of agricultural solid residue, but the mechanism of their action in the stabilization and carbon transformation of agricultural solid residue composting remains unclear. In this work, different treatments, including Control, Amm-1, Amm-2, Amm-3, and Amm-4, were established for co-composting of cow manure and wheat husk to investigate the action mechanism of Amm in composting stabilization and carbon conversion. The findings indicated that the Amm inoculation facilitated the decrease of total organic carbon, dissolved organic carbon, CO2 productions, and CH4 emissions by 35.13 ∼ 37.28 %, 15.61 ∼ 16.78 %, 1.75 % ∼ 32.38 %, and 10.30 %∼ 18.01 %, respectively. Among the treatments. The inoculation of Amm-4 immensely showed the highest improvement effect on the organic solid residue humification and carbon transformation process, with the final compost product showed high stability and favorable performance on improving crop growth. Further mechanism analysis suggested that the Amm inoculation optimized humification-related enzyme activity and fungal community structure, enhanced the humus formation, increased the humification index, and promoted the stabilization of final product. In conclusion, this investigation verified the Amm inoculation can improve compost carbon conversion and promote the green application of agricultural solid residue as resource.

Biostimulation potentials of spent milled maize and cowblood on a crude oil polluted soil

This study was carried out to investigate the biostimulation effect of the application of spent milled maize and cow blood to crude oil polluted soil. The treatment groups were; Control (0 L crude oil (CO) + 0 kg spent milled maize (SMM)), group 1 (1 L CO + 1 kg SMM + 1 L cow blood), group 2 (2 L CO + 2 kg SMM) and group 3 (5 L CO + 5 kg SMM). The experiment was laid out in a completely randomized design A total of four treatment combinations were applied and replicated 3 times giving a total of 48 plots.The physicochemical properties and bacterial load of the soil were determined before pollution, two weeks after pollution, four weeks and eight weeks after remediation. The results for physicochemical properties of soil indicates a decrease in total organic carbon and nitrogen while there was an increase in the levels of cation exchange capacity, phosphorus and electrical conductivity after crude oil pollution. The mean levels of total petroleum hydrocarbon and polycyclic aromatic hydrocarbon reduced after the pollution. The application of the spent milled maize and cow bloodwere observed to improve the physicochemical properties of soil. There was also an increased bacterial count for the treated groups compared to the control; the values ranged from 1.3 x 103cfu/g to 1.24 x 108cfu/g. The identified bacteria were Flavobacterium, Pseudomonas, Bacillus, Micrococcus, Proteus, Clostridium and Nocardia species.Generally, this study has revealed that spent milled maize and cow blood are effective in the restoration of crude oil polluted soil.

Photocatalytic Removal of Metronidazole Antibiotics from Water Using Novel Ag-N-SnO2 Nanohybrid Material.

In this study, we employed a straightforward synthetic approach using the sol-gel method to fabricate a novel photocatalyst, Ag and N co-doped SnO2 (Ag-N-SnO2). The synthesized photocatalysts underwent characterization through various techniques including XRD, FTIR, FESEM-EDS, TEM, UV-vis DRS, BET, and XPS. The UV-vis DRS results confirmed a reduction in the bandgap energy of Ag-N-SnO2, leading to enhanced absorption of visible light. Additionally, TEM data demonstrated a smaller particle size for Ag-N-SnO2, and BET analysis revealed a significant increase in surface area compared to SnO2.The efficiency of the Ag-N-SnO2 photocatalyst in degrading metronidazole (MNZ) under natural sunlight surpassed that of SnO2. Under optimal conditions (Ag-N-SnO2 concentration of 0.4 g/L, MNZ concentration of 10 mg/L, pH 9, and 120 min of operation), the highest MNZ photocatalytic removal reached 97.03%. The reaction kinetics followed pseudo-first-order kinetics with a rate constant of 0.026 min-1. Investigation into the mineralization of MNZ indicated a substantial decrease in total organic carbon (TOC) values, reaching around 56% in 3 h of sunlight exposure. To elucidate the photocatalytic degradation mechanism of MNZ with Ag-N-SnO2, a scavenger test was employed which revealed the dominant role of •O2-. The results demonstrated the reusability of Ag-N-SnO2 for up to four cycles, highlighting its cost-effectiveness and environmental friendliness as a photocatalyst.

A 1000-year record of paleoclimate and paleoenvironment change inferred from sedimentary organic matter in Lake Azuei, Haiti

We studied sediment organic matter (OM) to reconstruct the environment over the last millennium using a sediment core from Lake Azuei, Haiti, also known as “Etang Saumatre.” Chronology for the 84-cm-long core was established with 11 14C dates and 210Pb analysis. Total organic carbon (TOC) concentrations in the sediment were low (0.58 ‐ 4.89%), as were total nitrogen (TN) values (0.06 ‐ 0.40%). Carbon isotopic ratio (δ13C) values were relatively negative and C/N ratios were low, suggesting that algae and terrestrial C3 plants were the primary sources of OM in the lake sediment. The inverse relationship between the nitrogen isotopic ratio (δ15N) and TOC is related to denitrification in the sediment. We identified five stratigraphic zones using a δ13C vs. C/N cross diagram: 1) Medieval Climate Anomaly 1 (MCA1) (1000–1050 CE), 2) Medieval Climate Anomaly 2 (MCA2) (1050–1100 CE), 3) Transition period between Medieval Climate Anomaly and Little Ice Age (MCA-LIA) (1150–1400 CE) 4) Little Ice Age (LIA) (1400–1800 CE), 5) Current Warm Period (CWP) (1800–2000 CE). These stratigraphic zones correspond to three climate episodes. The first was applied MCA1 and LIA periods, when there was a decrease in TOC and TN as well as in plankton-derived OM. This was accompanied by an increase in δ15N, which suggests denitrification due to suboxic conditions, likely caused by an increase in lake water temperature and dry conditions. The second climate episode was the MCA-LIA transition period and was characterized by high variability of TOC, δ13C and δ15N. The organic matter deposited during this period appeared to be a mixture of material originating from both autochthonous phytoplankton and allochthonous C3 plants. There was climate instability during this period, with alternations between wet and dry conditions, and thus likely variations in lake level. The third climate episode, the MCA2 and CWP periods, was characterized by an increase in TOC and TN values, and decrease in δ13C and δ15N values. This was chiefly attributable to more organic material input which was derived from C3 terrestrial vegetation growing around the lake. A decrease in δ15N indicated a reduction in denitrification, further suggesting an increase in the input of organic matter. Sedimentation during these periods occurred when there was more transport related to wet conditions.

Mechanism of organic fouling in the reverse osmosis process of coal chemical wastewater

With the development and utilization of coal on a large scale, the treatment of coal chemical wastewater (CCW) had received extensive attention. This study utilized CCW from a coal liquefaction wastewater treatment plant to investigate the mechanism of organic fouling in the reverse osmosis (RO) process. CCW, which possessed high levels of organic matter, underwent RO process and resulted in significantly improved water quality, with a decrease in total organic carbon from 173.70 mg/L to 2.36 mg/L. However, the membrane surface was fouled by organic matter after continuous filtration for 14 h, causing a substantial reduction in the membrane flux, which decreased to 69.0 % normalized membrane flux. High molecular weight humic acid, the primary organic matter present in CCW, was found to be responsible for the organic fouling on the membrane surface, consistent with the main organic component of CCW. Moreover, organic foulants, including nitrogen heterocyclic compounds, alcohols, and lipids, were detected on the membrane surface. The study presented herein provides a comprehensive understanding and analysis of organic fouling in a RO system, offering crucial data support for the development of effective strategies to prevent and control RO membrane fouling in water treatment processes.

Use of Wastewater from Legume Cooking in Bioremediation of Crude-Oil Polluted Soil

Wastewaters generated from the cooking of foods contain nutrients. Such wastewaters may have the potential to be used as nutrients in bioremediation of hydrocarbon polluted environments. In this study, use of wastewaters generated from the cooking of two legumes as nutrient source during bioremediation of hydrocarbon polluted soil was investigated. Crudeoil polluted soils were treated with wastewater from cooking of cowpea (setup B), wastewater from cooking of groundnut-pods (setup G), a mixture of the wastewaters (setup B+G), and tap-water (control setup: setup C). Selected microbial group and physicochemical parameters were determined at seven days interval. The results obtained showed that the extent of hydrocarbon degradation in setup B, G, B+G, and C were 45.5, 23.2, 1.3, and 37.9 % respectively. There was decrease in total organic carbon (TOC), phosphorus, and nitrogen in the setups. However, in setup G there was increase in TOC. Setup C and B had the highest decrease in phosphorus, and setup B had the highest decrease in nitrogen. There was decrease and subsequent increase in percent hydrocarbon-utilizing bacteria in all the setups; the subsequent increase was highest in setup B. There was generally a decrease in percent hydrocarbon-utilizing fungi, except in setup C. The hydrocarbon utilizing microorganisms isolated from the treated soils include Bacillus, Micrococcus, Acinetobacter, Staphylococcus, Pseudomonas, Penicillium, Aspergillus, Candida and Fusarium. Their presence indicates that hydrocarbon degradation was due to biodegradation. It is concluded that wastewater from cooking of cowpeas can be applied in bioremediation of crude-oil polluted soil.

Tannic acid enhanced the removal of Phaeocystis globosa from seawater by Fe (II) activated persulfate

The frequent outbreaks of Phaeocystis globosa (P. globosa) blooms in coastal areas have seriously threatened nuclear power safety. In this study, tannic acid (TA) was used to accelerate the removal of P. globosa from seawater by Fe (Ⅱ) activated persulfate (PS). In comparison with the Fe (Ⅱ)-PS system, the higher removal efficiency of P. globosa was obtained in the TA-Fe (Ⅱ)-PS system (91.2% vs 67.5%). The removal efficiency of fluorescence value, chlorophyll a, turbidity and total organic carbon (TOC) reached up to 90.1%, 91.2%, 61.8% and 51.6% with the addition of 10 mg L−1 of TA, 100 mg L−1 of Fe (Ⅱ) and 240 mg L−1 of PS in 420 min. The flocs images confirmed that TA played a dual role in regulating Fe (Ⅱ) concentration and activating PS, which facilitated the pre-oxidation of algae cells. Finally, the inactivated P. globosa settled to the bottom with the iron mineral flocs. In addition, positive environmental impacts were also validated due to the decrease in total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP) and chemical oxygen demand (COD). The findings demonstrated that TA-Fe (Ⅱ)-PS system is a promising candidate for the removal of P. globosa from seawater.

Ketoprofen and diclofenac removal and toxicity abatement in a real scale sewage treatment Plant by photo-Fenton Process with design of experiments

The disposal of effluent and sludge containing emerging contaminants (ECs) are the main problems associated with most traditional treatment methods. Non-steroidal anti- inflammatory drugs (NSAIDs) require more complete treatments integrated with conventional processes to enable circular economy and the water-energy-food (WEF) nexus. Different options to traditional technologies have been employed in the treatment of effluents, such as advanced oxidation processes (AOPs). However, few studies use real scales integrated with existing technologies. This work evaluated the use of AOPs for the degradation of ketoprofen (KET), diclofenac (DCF), and the DCF+KET mixture in an anaerobic effluent matrix, post-treated by an Upflow Anaerobic Sludge Blanket Reactor (UASB) in a real-scale Sewage Treatment Plant (STP). A Factorial Experimental Design was proposed and after 2 h of treatment the efficiency was evaluated by the decrease in total organic carbon (TOC), decrease of drugs concentration, physicochemical and ecotoxicity parameters. As a result, the photo-Fenton process showed greater efficiency in the degradation of KET (97.2% ± 1.6), DCF (72.7% ± 4.9), and the mixture of the two drugs DCF+KET (66.0% ± 2.5), improved the quality of the effluent in the removal of COD, BOD, and turbidity, and reduced toxicity in tests performed with Artemia sp. and Lactuca sativa. The integration between AOPs and UASB as a sewage treatment technology widely used as primary and secondary treatment, allowed to optimize the sewage treatment system for an ideal arrangement. As a consequence, it possesses the capacity to eliminate conventional organic matter and efficiently degrade emerging pollutants.

Optimization of iron-ZIF-8 catalysts for degradation of tartrazine in water by Fenton-like reaction

Optimization of iron zeolitic imidazole framework-8 (FeZIF-8) nanoparticles, as heterogeneous catalysts, were synthesized and evaluated by the Fenton-like reaction for to degrade tartrazine (Tar) in aqueous environment. To achieve this, ZIF-8 nanoparticles were modified with different iron species (Fe2+ or Fe3O4), and subsequently assessed through the Fenton-like oxidation. The effect of different parameters such as the concentration of hydrogen peroxide, the mass of catalyst and the contact time of reaction on the degradation of Tar by Fenton-like oxidation was studied by using the Box-Behnken design (BBD). The BBD model indicated that the optimum catalytic conditions for Fenton-like reaction with an initial pollutant concentration of 30 ppm at pH 3.0 were T = 40 °C and 12 mM of H2O2, 2 g/L of catalyst and 4 h of reaction. The maximum Tar conversion value achieved with the best catalyst, Fe1ZIF-8, was 66.5% with high mineralization (in terms of decrease of total organic carbon – TOC), 44.2%. To assess phytotoxicity, the germination success of corn kernels was used as an indicator in the laboratory. The results show that the catalytic oxidation by Fenton-like reaction using heterogeneous iron ZIF-8 catalysts is a viable alternative for treating contaminated effluents with organic pollutants and highlighted the importance of the validation of the optimized experimental conditions by mathematical models.

Pore Structure Characterizations of Shale Oil Reservoirs with Heat Treatment: A Case Study from Dongying Sag, Bohai Bay Basin, China.

Heat treatment plays a significant role in determining the petrophysical properties of shale reservoirs; however, the existing studies on the evolution of pore structures are still insufficient. This study conducts a series of tests, including Rock-Eval, low-temperature nitrogen adsorption-desorption, nuclear magnetic resonance (NMR) T2, and T1-T2 tests on samples from Shahejie Formation, Dongying Sag, Bohai Bay Basin. The tests aim to determine the changes in the shale pore structures under increasing heat treatments (ranging from 110 to 500 °C) and identify the factors that control pore structures. The results show that the gradual decomposition of organic matter leads to an eventual decrease in the total organic carbon (TOC) content. The decrease in TOC is more prominent when the temperature exceeds 300 °C. For shales with lower TOC contents (<2%), the Brunauer-Emmett-Teller specific surface area (BET SSA) first decreases, then increases, but eventually decreases again. However, the average pore diameter demonstrates an opposite trend when the temperature increases. In contrast, for organic-rich shales (TOC > 2%), the BET SSA increases at temperatures above 200 °C. The similarity between the D1 values implies that the complexity and heterogeneity of shale pore surface only undergo minor changes during heat treatment. Porosity shows an increasing trend, and the higher the contents of clay minerals and organic matter in shales are, the greater the change in porosity is. The NMR T2 spectra suggest that micropores (<0.1 μm) in shales first decrease and then increase, whereas the contents of meso- (0.1-1 μm) and macropores (>1 μm) increase, corresponding to the increase in free shale oil. Moreover, shale pore structures are primarily controlled by clay minerals and organic matter contents during heat treatments, with higher contents resulting in better pore structures. Overall, this study contributes to detailing the shale pore structure characteristics during the in situ conversion process (ICP).

Miscanthus x giganteus stress tolerance and phytoremediation capacities in highly diesel contaminated soils

Second generation biofuel crop Miscanthus x giganteus (Mxg) was studied as a candidate for petroleum hydrocarbons (PHs) contaminated soil phytomanagement. The soil was polluted by diesel in wide concentration gradient up to 50 g⋅kg−1 in an ex-situ pot experiment. The contaminated soil/plant interactions were investigated using plant biometric and physiological parameters, soil physico-chemical and microbial community's characteristics. The plant parameters and chlorophyll fluorescence indicators showed an inhibitory effect of diesel contamination; however much lower than expected from previously published results. Moreover, lower PHs concentrations (5 and 10 g⋅kg−1) resulted in positive reinforcement of electron transport as a result of hormesis effect. The soil pH did not change significantly during the vegetation season. The decrease of total organic carbon was significantly lower in planted pots. Soil respiration and dehydrogenases activity increased with the increasing contamination indicating ongoing PHs biodegradation. In addition, microbial biomass estimated by phospholipid fatty acids increased only at higher PHs concentrations. Higher dehydrogenases values were obtained in planted pots compared to unplanted. PHs degradation followed the first-order kinetics and for the middle range of contamination (10–40 g⋅kg−1) significantly lower PHs half-lives were determined in planted than unplanted soil pointing on phytoremediation. Diesel degradation was in range 35–70 % according to pot variant. Results confirmed the potential of Mxg for diesel contaminated soils phytomanagement mainly in PHs concentrations up to 20 g⋅kg−1 where phytoremediation was proved, and biomass yield was reduced only by 29 %.

Synthesis and characterization of rGO/Fe0/Fe3O4/TiO2 nanocomposite and application of photocatalytic process in the decomposition of penicillin G from aqueous

In this study, we synthesized rGO/Fe0/Fe3O4/TiO2 nanocomposite according to Hummer's, and straightforward sol-gel method. The FESEM, EDX, TEM, FT-IR, XRD, BET, UV spectra, and VSM analysis were applied to determine the catalyst properties. Optimization of influence parameters on photocatalytic process performance to penicillin G degradation in aqueous media. pH (4–8), nanocomposite dose (10–20 mg/L), reaction time (30–60 min), and penicillin G concentration (50–100 mg/L) were optimized via central composite design. In the optimum condition of PCP, supplementary studies were done. As a result of the analysis, the nanocomposite was well synthesized and displayed superior photocatalytic properties for degrading organic pollutants. In addition to being magnetically separable, the synthesized rGO/Fe0/Fe3O4/TiO2 nanocomposite exhibits high recyclability up to 5 times. The quadratic model of optimization is based on the adjusted R2(0.99), and predicated R2(0.97) suggested. According to the analysis of variance test, the model was significant (F-Value = 162.95, P-Value = 0.0001). Photocatalytic process is most efficiently decomposed at pH = 6.5, catalyst dose = 18.5 mg/L, reaction time = 59.1 min, and penicillin G concentration = 52 mg/L (efficiency = 96%). The chemical oxygen demand and total organic carbon decrease were 78, and 65%. The photolysis and adsorption mechanism as a single mechanism had lower performance in penicillin G degradation. Benzocaine had the greatest effect on reducing the efficiency of the process as a radical scavenger. The °OH, h+, and O2●– were the main reactive oxidant species in penicillin G removal. Phenoxyacetaldehyde, Acetanilide, Diacetamate, Phenylalanylglycine, N-Acetyl-l-phenylalanine, Diformyldapsone, and Succisulfone were the main intermediates in penicillin G degradation. The results indicated the photocatalytic process with rGO/Fe0/Fe3O4/TiO2 nanocomposite on a laboratory scale has good efficiency in removing penicillin G antibiotic. The application of real media requires further studies.

Transformation of organic carbon through medium pressure (polychromatic) UV disinfection of wastewater effluent during wet weather events

An observed decrease in total organic carbon (TOC) and dissolved organic carbon (DOC) concentrations following wastewater disinfection with medium pressure (MP, polychromatic) ultraviolet (UV) irradiation during wet weather flows is investigated. When antecedent rainfall in the previous 7-days was >2 in (5 cm), TOC and DOC concentrations decreased dramatically following MP-UV disinfection. Organic carbon surrogate measurements of biological oxygen demand (BOD), TOC, DOC, turbidity, UVA – 254 nm, SUVA (specific UVA), scanning UV–Visible spectra (200–600 nm), fluorescence excitation-emission matrix (EEM) spectra, and light scattering data are presented for wastewater resource recovery facility (WRRF) influent, secondary effluent (pre-UV-disinfection), and MP-UV-disinfected (final effluent) samples. TOC and DOC in wastewater influent and secondary effluent (i.e., pre-UV disinfection) correlated with antecedent rainfall conditions. The percent TOC and DOC removal through secondary treatment (i.e., from influent to effluent pre-UV) and the percent TOC and DOC removal through MP-UV disinfection (i.e., from effluent pre-UV to effluent post-UV) were compared and the latter approached 90 % through MP-UV disinfection during high antecedent rainfall conditions. Spectroscopy (UV, visible, or fluorescence) was performed on samples after filtration through 0.45 μm filters, i.e., the operationally defined DOC fraction of aquatic carbon. Scanning UV–visible spectra indicated transformation of an unidentified wastewater component into light-scattering entities regardless of antecedent rainfall conditions. The types of organic carbon (diagenetic, biogenic, or anthropogenic) and the significance of wet weather are discussed. An organic carbon contribution via infiltration and inflow was attributed as a source-of-interest in this research.

Insight into the microbial mechanisms for the improvement of spent mushroom substrate composting efficiency driven by phosphate-solubilizing Bacillus subtilis

The objective of this study was to investigate the microbial mechanisms for the improvement of composting efficiency after Bacillus subtilis inoculation with soluble phosphorus function in the spent mushroom substrate (SMS) aerobic composting. The methods in this study, including redundant analysis (RDA), co-occurrence network analyze and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt 2) were carried out studying the dynamic changes of phosphorus (P) components, microbial interactions and metabolic characteristics in the SMS aerobic composting inoculated with phosphorus-solubilizing B. subtilis (PSB). An increase in germination index (GI) (up to 88.4%), total nitrogen (TN) (16.6 g kg−1), available P content (0.34 g kg−1) and total P (TP) content (3.20 g kg−1) and a decrease in total organic carbon (TOC), C/N and electrical conductivity (EC) in final composting stage indicated B. subtilis inoculation could further improve maturity quality of the composting product compared with CK. Other results also demonstrated that PSB inoculation increased the stability of compost, humification degree and bacterial diversity, contributing to P fractions transformation in the composting process. Co-occurrence analysis suggested that PSB strengthened microbial interactions. Metabolic function of bacterial community analysis showed pathways such as carbohydrate metabolism, and amino acid metabolism in the composting were increased by effects of PSB inoculation. In summary, this study reveals a useful basis for better regulating the P nutrient level of the SMS composting and reducing environmental risks by inoculating B. subtilis with P solubilizing function.

Petrological and chemical characterizations of pristine and reworked phosphorites from Negev, Israel: Insights into industrial usage

Phosphorites are an essential natural resource for producing phosphoric acid, phosphate fertilizers, and phosphate-based products. Detailed characterization and an appropriate assortment of phosphate resources are necessary to identify rocks that are chemically suitable for the phosphate industry. In the present study, we investigated the chemical composition and petrographic characteristics of phosphorites from three phosphate fields located in the same syncline, Zin Negev, Israel. At each site, the succession of pristine and reworked phosphorite layers along 10 m of the section was observed. Based on the chemical and petrographic analysis of phosphorites, it can be concluded that even though all the studied phosphorites were deposited in the same basin under suboxic conditions, the sedimentary settings are varied at each site. These variations resulted in differences in sedimentary structures and chemical composition, including the concentrations of major and trace elements and the abundance of the organic matter fractions. In all studied samples, a decrease in total organic carbon and redox-sensitive trace elements was observed upon the transition from a pristine to a reworked phosphorite phase, while the relative abundance of organic matter fractions remained nearly constant. The results of the present study indicate that, in addition to high-quality phosphorites at anticlinal heights, phosphorites with low organic matter contents in synclines can also be suitable for industrial applications. However, in phosphates, where humic substances represent the main fraction of OM that is located inside carbonate-fluorapatite grains, difficulties in the separation of OM from carbonate-fluorapatite grains during the production process cannot be excluded.

Bioconversion of fruit waste and sewage sludge mixtures by black soldier fly (Diptera: Stratiomyidae) larvae

Bioconversion of fruit waste (FW) and sewage sludge (SS) sludge mixtures into valuable products was investigated using black soldier fly (Hermetia illucens) larvae (BSFL) under a lab-scale trial. For that, five different setups of FW and SS mixtures (100FW; 100SS; 70SS+30FW; 50SS+50FW; 70FW+30SS) were prepared and changes in larval biomass, feed loss, and residual waste physicochemical properties were estimated until the emergence of fly in all waste mixtures. BSFL caused a significant decrease in total organic carbon (11.71–34.79%) and carbon-to-nitrogen ratio (C/N ratio) while the increase in total nitrogen (8.35–123.30%), total phosphorus (17.02–143.36%), and total potassium (19.40–48.87%) contents in the feedstock. The germination index and C/N ratio of frass were below the standards decided for manure quality in a few setups suggesting the non-stability of frass for agronomic applications due to the short duration (20 d) of composting. Larval biomass yield, feed conversion ratio and nutrient mineralization were found to be higher in 50SS+50FW and 70FW+30SS feedstock combinations suggesting their suitability as ideal feedstock for optimal BSFL cultivation. The impact of toxic substances in sewage on BSFL survival, growth and waste stabilization processes, and frass metal enrichment could be investigated in future studies.

Impact of natural weathering on source rocks: Organic and inorganic geochemical evidence from the Triassic Chang 7 outcrop profile in Tongchuan of the Southern Ordos Basin (China)

Exposure of buried source rocks at or near the surface causes organic matter (OM) to be subjected to loss through weathering impacts. A detailed organic and inorganic investigation of the natural weathering of the Triassic Chang 7 Yishicun Profile in Tongchuan City of the Ordos Basin revealed pronounced changes in bulk, molecular, mineral, and elemental compositions. In this study, systematic and visible variations caused by natural weathering were shown in the amount and composition of both organic (kerogen and extractable organic matter [EOM]) and inorganic matter (minerals and elements). The results indicate that natural weathering could substantially affect the characteristics of source rocks at a depth of 2 m from the surface, resulting in a 41% decrease in total organic carbon (TOC) and a 75% loss of EOM. Furthermore, changes were noted in kerogen elemental compositions, fractional compositions of EOM, and some geochemical parameters from Rock-Eval pyrolysis. The mineral and major, trace, and rare earth element (REE) compositions of the outcrop samples were also analysed and compared. The weathering of source rocks was mainly due to the influence of surface water leaching and biodegradation of the OM. This resulted in the oxidation of kerogen and the preferential depletion of low-carbon-number n-alkanes and low-molecular-weight high-water-solubility biomarkers. This has led to bias in petroleum geochemical interpretation based on these organic geochemical parameters. The major elemental composition indicated that the outcrop profile was moderately weathered. Moreover, some commonly used palaeoenvironmental geochemical proxies, including U/Th, AU, Mo, Sr/Ba, Sr/Cu, and P/Ti, display varying degrees of weathering-related alteration. However, other palaeoenvironmental proxies such as V/(V + Ni), Ni/Co, V/Cr, δU, and Ceanom experienced little variation and remained reliable for environmental interpretation. Thus, petroleum resource evaluation and sedimentary environmental analysis of source rocks based on outcrop samples should consider the effects of natural weathering.

Siliceous termite hill supported ZnO-TiO2 as a solar light responsive photocatalyst: Synthesis, characterization and performance in degradation of methylene blue dye

Colored contaminants in wastewater need to be removed prior to discharge due to their negative impacts on public health and the environment. Herein, immobilized TiO2 on termite hill (TiO2/TH) and ZnO-promoted TiO2/TH (ZnO-TiO2/TH) were synthesized, evaluated by different characterization techniques (XRF, XRD, FTIR, UV-Vis DRS, N2 adsorption-desorption analysis and SEM), and the possibility of using them as photocatalysts for methylene blue (MB) degradation under solar irradiation investigated. The influence of photocatalytic reaction parameters (initial MB concentration, photocatalyst dosage and solution pH) was studied at fixed irradiation time. XRD and SEM results, among other analyses revealed successful incorporation of ZnO and TiO2 on structured support (TH), while UV-Vis analysis affirmed reduction in band gap energy due to immobilizing effect. The optimized photocatalytic degradation variables were 50 mg/L dye concentration, 1.2 g/L photocatalyst dosage and 6.0 pH. The ZnO-TiO2/TH showed better photoactivity for MB degradation than TiO2/TH under the same conditions which could be attributed to a reduction in band gap energy from 2.94 eV to 2.85 eV upon addition of ZnO. More than 80% degradation efficiency was achieved after the 7th cycle, depicting better stability. A pseudo-first-order Langmuir-Hinshelwood model with a rate constant of 0.0774 min−1 and R2 of 0.9971 at optimum dye concentration (50 mg/L) appeared to best describe the photocatalytic degradation kinetic data. The UV-Vis spectra changes and decrease in total organic carbon indicated that ZnO-TiO2/TH photocatalyst has the prospect to degrade organic pollutants in industrial effluent completely.