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Approximately 20% of concentrate will be produced from coal gasification wastewater after reverse osmosis treatment. The organic matter contained in the concentrate affects its evaporation crystallisation; therefore, the refractory organics must be removed. In this study, Cu-Co-Mn/AC catalytic ozonation was used to treat reverse osmosis concentrate (ROC). With the addition of the Cu-Co-Mn/AC catalyst, the production of ·OH increased by 82 μmol/L, thereby enhancing the ozonation performance. The pH, ozone dosage, and catalyst dosage all affected the catalytic ozonation performance. By constructing a response surface model, it was found that the catalyst dosage had the most significant effect on the catalytic ozonation performance. The predicted optimal reaction conditions were pH = 9.02, ozone dosage = 1.08 g/L, and catalyst dosage = 1.33 g/L, under which the chemical oxygen demand (COD) removal reached a maximum of 81.49%.

The cultivation of Chlorella vulgaris in sludge extract (SE) from municipal excess sludge diluted with BG11 medium was investigated to achieve sludge reduction and microalgae cultivation. A maximum biomass of 1.404 ± 0.101 g/L was achieved at 15 days in a mixture of 25% BG11 and 75% sludge extract under 10,000-lx light. In early culture periods, heterotrophy dominated the process in the group with a high proportion of sludge extract of excess sludge extract containing relatively high amounts of organic material, which led to enhanced citrate synthase enzyme activities and reduced rubisco enzyme activities. Moreover, increasing the light intensity did not significantly improve biomass production due to its inhibitory effects on respiration in the early culture stages. The response surface model showed that organic matter was the main factor influencing biomass production from 0 to 2 days. The influence of light intensity on biomass production became more noticeable only after depleting the organic matter in sludge extract.

The low temperature of sewage in north China results in low performance of biological treatment at municipal wastewater treatment plants (MWTPs), especially in biological nitrogen removal. A modified two-stage A/O process with an embedded biofilm was proposed to enhance nitrogen removal. The operation performance of a pilot test was compared with an A2/O and SBR process at existing MWTPs to investigate the resistance to low temperature. The microbial communities for the three processes were compared based on the metagenomics results of 16sDNA high-throughput sequencing from activated sludge. The modified A/O resulted in a higher average removal of COD (90.12%) than A2/O (85.23%) and SBR (83.03%), especially of small-molecule organic compounds ( 5 k Da); the TN removal rate of A2/O, SBR and the modified A/O was also increased from 74.47%, 70.63% and 78.46%, respectively. High-throughput sequencing revealed increased microbial diversity and an abundance of denitrifying functional bacteria was observed in the modified A/O process at low temperatures. The abundance of nitrite oxidation bacteria (NOB) including Nitrosomonas and Nitrospira, the amount was 1.76% and 2.34% in modified A/O, respectively, whereas NOB only accounted for 1.82% in A2/O and 1.35% in SBR.

As a common pretreatment process for coal chemical wastewater, the conventional one-stage coagulation process has the problem of poor removal of small size oil, which will inhibit the subsequent biological treatment. Measures to improve oil removal efficiency based on the development of new coagulants and the addition of composite processes are common in the literature, but two-stage coagulation to improve coagulation efficiency has not been reported to date. Here, we optimized coagulation parameters and compared the oil removal efficiency of two-stage coagulation and one-stage coagulation. Under the same total dosage of coagulant (PAC), the optimum removal of oil in two-stage coagulation was achieved 90% which increased by 11% compared to one-stage process. P10 and P 1 μm were proposed to evaluate the oil removing effect of two-stage coagulation. In addition, SEM scanning was used to conduct flocs analysis and two-stage coagulation process simulation, revealing the principle of the excellent oil removal performance of two-stage coagulation. Finally, coagulant in filter residue was recovered by acidification method and the recovered coagulant was used again in the two-stage coagulation process of coal chemical wastewater. These results suggest that two-stage coagulation is a cost-effective alternative oil removal technique with high energy efficiency and environmental benign. This research may offer helpful insights to develop an advanced oil removal process.

Chlorella vulgaris (C. vulgaris) and Scenedesmus obliquus (S. obliquus) were compared to remove toxicity under conditions of sludge extract cultivation for 30 days. The toxicity of sludge extract, the growth characteristics, photosynthetic pigment, superoxide dismutase (SOD) enzyme and catalase (CAT) enzyme activities of the two microalgae were studied by contrast. The results showed that small molecular organic matter (500 Da) was more easily utilized by microalgae. The toxicity in the toxic group of C. vulgaris and S. obliquus on the 30

Large amounts of toxic excess sludge as well as high concentrations of carbon dioxide can be produced in coal-gasification industry. Microalgae has huge potential in the use of nutrients, the removal of toxic organic matter in excess sludge and CO

The correlation between sludge reduction induced by 2,4,6-trichlorophenol (2,4,6-TCP) as an uncoupler and sludge toxicity was investigated in sequence batch reactors over a 100-d operation period. The influent concentrations of 2,4,6-TCP tested were 10 mg/L, 30 mg/L, and 50 mg/L. Sludge reduction, chemical oxygen demand (COD) removal rate, and sludge toxicity were measured. The results showed that from 30 to 80 d, when the COD removal rate was at an acceptable level, the sludge reduction levels for the 10 mg/L, 30 mg/L, and 50 mg/L groups were 9.7%, 31.6%, and 41.5%, respectively, and the average sludge toxicity values were 24.2%, 38.0%, and 53.0%, respectively. Sludge reduction was positively correlated with sludge toxicity. The two-dimensional polyacrylamide gel electrophoresis/results showed that extracellular and intracellular proteins secreted by the activated sludge during uncoupling metabolism were positively correlated with sludge toxicity. Taking the COD removal rate, sludge reduction, and sludge toxicity into consideration, the optimal influent concentration of the uncoupler 2,4,6-TCP was 30 mg/L when the initial mixed liquid suspended solids of sludge was 2,500 mg/L.

High concentration of nitrogen and phosphorus (above 20 and 1.5 mg/L, respectively, for TN and TP) and low ratio of nitrogen to phosphorus (10–15 for N/P) in secondary effluent of cities in China a...

High concentration of nitrogen and phosphorus and imbalance of N/P can lead to the formation of water and the malignant proliferation of toxic microalgae. This study put forward the advanced nutrient removal with the regulation of effluent N/P as the core in order to restrain the eutrophication and growth of poisonous algae. According to the preliminary study and review, the optimal N/P for non-toxic green algae was 50:1. The horizontal sub-surface flow constructed wetland was filled with steel slag and ceramsite to achieve the regulation of effluent N/P. The results showed that steel slag had the stable P removal capacity when treating synthetic solution with low P concentration and the average removal rate for 1.5, 1.0, and 0.5 mg/L synthetic P solution was 2.98 ± 0.20 mg kg−1/h, 2.26 ± 0.15 mg kg−1/h, and 1.11 ± 0.10 mg kg−1/h, respectively. Combined with P removal rate and P removal task, the filling amount of steel slag along the SSFCW (sub-surface flow constructed wetland) was 3.22 kg, 4.24 kg, and 4.31 kg. In order to ensure the stability of dephosphorization of steel slag, the regeneration of P removal capacity was investigated by switching operation of two parallel SSFCW in 20 days for cycle. The N removal was limited for the deficiency of carbon source (COD (chemical oxygen demand)/TN = 3–4), and was stable at 18.5–31.9% which was less affected by temperature. Therefore, by controlling the process of quantitative P removal of steel slag, the effluent N/P in SSFCW can be stable at 40–60:1 in the whole year, so as to inhibit the malignant proliferation of toxic algae.

Hydroquinone is one of the main pollutants in coal-gasification wastewater, which is biologically toxic and difficult to remove. The aerobic biodegradation rate, organic toxicity, and microbial community structure at different acclimation stages of degradation of hydroquinone by activated sludge were investigated. In each acclimation cycle, the removal of hydroquinone reached 100% after 5 days, indicating that high-concentration hydroquinone in the activated sludge could be completely biodegraded. When the microbial flora was inhibited by the influent hydroquinone, the enzyme system experienced stress conditions and led to the secretion of secondary metabolites, extracellular protein of 5-10 kDa mainly contributing to the sludge organic toxicity. Microbial diversity analysis showed that with the increase of the concentration of hydroquinone, β-Proteus bacteria such as Azoarcus and Dechloromonas gradually accumulated, which improved the removal of hydroquinone with aerobic activated sludge in the sequencing batch reactor (SBR) system. As the inhibition degree exceeded the appropriate tolerance range of microorganisms, bacteria would secrete much more secondary metabolites, and the organic toxicity of sludge would reach a relatively high level.

The aerobic biodegradation rate, organic toxicity and microbial community structure of activated sludge acclimated by catechol, resorcinol and hydroquinone were investigated, to study the relationship between microbial structure and sludge organic toxicity caused by phenolic compounds. At the stable operation stage, the degradation rates of the dihydroxy benzenes in a single sequencing batch reactor (SBR) cycle were followed the order: resorcinol (89.71%) > hydroquinone (85.64%) > catechol (59.62%). Sludge toxicity bioassay indicated that the toxicity of sludge was catechol (45.63%) > hydroquinone (40.28%) > resorcinol (38.15%). The accumulation of secondary metabolites such as 5–10 kDa tryptophan and tyrosine protein substances caused the differential sludge toxicity. Microbial metagenomic analysis showed that the toxicity of sludge was significantly related to the microbial community structure. Thauera, Azoarcus, Pseudomonas and other Proteobacteria formed in the sludge during acclimation. Catechol group had the least dominant bacteria and loop ring opening enzyme genes (catA, dmpB, dxnF, hapD) numbers. Therefore, the degradation of catechol was the most difficult than resorcinol and hydroquinone, resulting the highest sludge toxicity.

In order to utilize the excess sludge and reduce the cost of algal cultivation, Chlorella vulgaris was cultivated in increasing proportions of sludge extracts for simultaneous nutrients removal and algal utilization. Results showed that C. vulgaris cultivated in the 100% sludge extract gained the highest total biomass (33.98 ± 0.30 × 106 cells/mL) and showed good results in TOC (absolute value 175 mg/L) and nutrients (TN: 77.1%; TP: 95.0%) removals. According to the Excitation-emission matrix spectra (EEMs) analysis, the 8th day was suggested as the optimal time for biomass harvesting. Although the lipid contents showed a negative correlation with the proportion of sludge extract, the FAME analysis showed that the saturated fatty acids (SFA) contents decreased and the unsaturated fatty acids (UFA) content increased as the concentration of sludge extract increased. The 100% sludge extract could be a desirable alternative medium for the algae cultivation.

BACKGROUND: The cultivation of Chlorella vulgaris present in toxic sludge extract from resorcinol‐rich wastewater was investigated to simultaneously determine the biomass production and toxicity removal. RESULTS: A comparison of the blank and the toxic sludge extract revealed that the sludge toxicity originating from the degradation of resorcinol was highly correlated to the mass fraction at 5000–10000 Da (R = 0.987, P = 0.013) and led to a decline in biomass (1.49 g L⁻¹ to 1.36 g L⁻¹ in 30 days) along with a reduced utilization rate of organics in the sludge extract, especially in the early stage (0–5 days) of culture. The effects of sludge toxicity were characterized by the downregulation of proteins associated with carbon (C) metabolism and the upregulation of proteins involved in photoreaction by proteomics. CONCLUSION: The sludge toxicity directly caused a decline in biomass production of C. vulgaris resulting from the downregulation of C metabolism. However, the promotion of biomass for heterotrophism was more significant than the inhibitory effect in the toxic sludge extract when compared with BG11 medium. © 2018 Society of Chemical Industry

This paper is based on the papers published in recent 10 years (2001-2022) from The British Journal of Aesthetics and The Journal of Aesthetics and Art Criticism, both of which enjoy high reputation in the aesthetic field. This paper uses scientific knowledge mapping and draws the knowledge mapping by using CiteSpace. Guided by visualization of conclusions, it outlines some development trends of aesthetics discipline and presents the research hot spots and changes of international aesthetics from a new perspective. Then this paper discusses the characteristics of aesthetics itself.

Due to the higher uncertainty of environmental risk for pollutants’ treatment by activated sludge, 10 mg/L influent 4‐chlorophenol (4‐CP) treated via a sequencing batch reactor (SBR) was used as acclimated SBR. Another SBR was used as control SBR without 4‐CP. The effects of hydraulic retention time (HRT) and proteins on sludge toxicity for 4‐CP treatment were analysed, and compared to the control SBR. Results showed that the sludge toxicity in acclimated SBR was significantly higher than that of the control SBR. Shortening HRT from 12 to 8 hours was beneficial to degrade 4‐CP and lower sludge toxicity. The identified highly expressed protein of ABC transporter co‐existed in control and acclimated SBRs, while other proteins of TonB‐dependent receptor, heat shock 70 kDa protein and superoxide dismutase in acclimated sludge were overexpressed relative to the control sludge, which played an important function in degrading 4‐CP, resisting 4‐CP toxicity and eliminating sludge toxicity.

Chlorella vulgaris was cultivated in different proportions of activated sludge extracts, which was from the treatment of synthetic wastewater containing tetrachlorophenol. The growth period of C. vulgaris could be shortened for about 10 days when sludge extract was mixed into BG11 culture substrate, and the growth of C. vulgaris was promoted during the period of adaptation and logarithmic period. In the stable and decay period, when the proportion of sludge extract increased to 50%, cell proliferation was inhibited. There was an evident positive correlation between the total and average amount of starch polysaccharide with sludge concentration. When C. vulgaris was cultivated with pure sludge extracts, the total amount of starch and polysaccharide was up to 103 and 125 mg/L. Therefore, the low-toxic sludge extracts were more beneficial to the accumulation of carbohydrates. In the 100% sludge extracts culture medium, chlorophyll-a in C. vulgaris was accumulated to 30.2 mg/L on the 25th day. Through the analysis of algal cells' ultrastructures, it was shown that the photosynthesis was strengthened greatly with low-toxic sludge extracts. The results show that the rich heterotrophic carbon source in the sludge extract can be used as an excellent medium for Chlorella. It provides new ideas for the harmless utilization of surplus sludge as a resource. At the same time, the use of nutrients in the sludge extract to cultivate Chlorella is of great significance to low-cost algae cultivation.

This study presents financial network indicators that can be applied to inspect the financial contagion on real economy, as well as the spatial spillover and industry aggregation effects. We propose to design both a directed and undirected networks of financial sectors of top 20 countries in GDP based on symbolized transfer entropy and Pearson correlation coefficients. We examine the effect and usefulness of the network indicators by newly using them instead of the original Dow Jones financial sector as explanatory variables to construct the higher-order information spatial econometric models. The results demonstrate that the estimated accuracies obtained from both the two networks are improved significantly compared with the spatial econometric model using the original data. It indicates that the network indictors are more effective to capture the dynamic information of financial systems. And meanwhile, the accuracy based on the directed network is a little higher than the undirected network, which indicates the symbolized transfer entropy, i.e. the directed and weighted network, is more suitable and effective to reflect relationships in the financial field. In addition, the results also show that under the global financial crisis, the co-movement between financial sectors of a country/region and the global financial sector as well as between financial sectors and real economy sectors is increased. However, some sectors in particular Utilities and Healthcare are impacted slightly. This study tries to use the financial network indicators in modeling to study contagion channels on the real economy and the industry aggregation effects and suggest how network indicators can be practically used in financial fields.

Considering carbon sources are often supplied to satisfy the removal of high nitrogen and refractory pollutants in industrial wastewater, two sequencing batch reactors (SBRs) were used in this study to treat 1.5 ± 0.5 mg/L 4-chlorophenol (4-CP) wastewater containing ammonium nitrogen and phosphate with different carbon sources. The favorable removal efficiencies of influent COD, NH4+-N, PO43−-P, and 4-CP suggested that the both SBRs were not influenced by supplying dissolved starch and sodium acetate, respectively. The phyla Proteobacteria and Bacteroidetes were dominant in both SBRs, while the dominant phylum Candidatus Saccharibacteria was only existed in SBR with carbon source of dissolved starch. The relative abundance of bacterial communities had significant differences at class, family, and order level in both SBRs. And the mutually dominant genus in both SBRs was only Gemmobacter, which was first found in 4-CP wastewater treatment. The changed extracellular polymeric substances (EPS) were related with microbial communities.

Chlorella vulgaris was cultivated in varying proportions of toxic sludge extracts obtained from a sequencing batch reactor for treating synthetic wastewater containing chlorophenols. C. vulgaris could reduce the ecotoxicity from sludge extracts, and a positive correlation was noted between ecotoxicity removal and total organic carbon removal. In terms of cell density, the optimal proportion of sludge extracts required for the cultivation of C. vulgaris was lower than 50%. The correlation between protein content in per 106 algae and inhibition extent of ecotoxicity of the 5 groups on the day of inoculation (0.9182, p

In this study, the effects of elevated influent 4-chlorophenol (4-CP) loads on components of polysaccharides and proteins and toxicity as well as their correlation in an activated sludge process were investigated. The toxicity in sludge was evaluated via a luminescent bacterium acute toxicity bioassay. Activated sludge, which was gradually acclimated via elevating influent 4-CP loads in a sequencing batch bioreactor (SBR), was used as the acclimated SBR. Another operated SBR without influent 4-CP was used as the control SBR. Results showed that after activated sludge was successfully acclimated with 10 mg/L influent 4-CP, the influence of gradually elevated 4-CP loads on acclimated SBR was insignificant and the influent 4-CP was quickly degraded. However, the main components of polysaccharides and proteins in activated sludge had a significant change and the sludge toxicity basically increased with the elevated influent 4-CP loads. The correlation between the proteins and toxicity in activated sludge was significantly higher than that of the correlation between the polysaccharides and toxicity at different influent 4-CP loads. Proteomics analysis indicated that the up-regulated proteins in acclimated SBR directly or indirectly played a significant role in degrading 4-CP, resisting 4-CP toxicity and reducing sludge toxicity.

Nonradical-based advanced oxidation processes are a promising method for pollutant removal due to their inherent superior characteristics. In this study, carbon nitride-based cuprous catalysts (CuCN) synthesized through a one-pot method were discovered as effective peroxydisulfate (PDS) activators for the degradation of Tetrabromobisphenol A (TBBPA). Specifically, TBBPA (2 mg L−1) was completely removed in 20 min under optimized conditions (2 mM PDS, 0.2 g L −1 1-CuCN, and initial pH = 7). The degradation efficiency of TBBPA was hardly inhibited by free radical scavengers and typical background water constituents. The results of XPS, FTIR, and DFT confirmed that Cu(I) atoms in CuCN not only act as active sites, but also form the specific Cu(I) − N bonds that increases the charge density of positively charged carbon atoms of the tri-s-triazine structure, which enhances the ability of CuCN to activate PDS. A comprehensive study was conducted by using radical scavengers, electron paramagnetic resonance and different dissolved oxygen conditions to identify the reactive oxygen species (ROS). Singlet oxygen (1O2) was unveiled to be the primary ROS in the 1-CuCN/PDS system, which was generated from superoxide anions (36.2%) and dissolved oxygen (63.8%). This study first elucidated the mechanism that carbon nitride-based cuprous catalysts activated PDS and provided an innovative PDS-based catalytic system for in situ chemical oxidation (ISCO).