Search

The purpose of this study was to research the differences and connection between examination-oriented education and quality education which are two significant educational systems nowadays. Based on the concrete phenomenon in China, British and United States, offering some proposals on Chinese educational system, and combine advanced educational concepts and guaranteed accountability system in British and US to lead a new way for Chinese quality education. Psychological method is also a valid method for Chinese high schools so that the students can feel the advantages of quality education.

Pyrolysis carbonization of sewage sludge is employed to achieve carbon sequestration and access carbon resources, while the quality of the obtained sludge-based carbon (SBC) is poor due to high ash contents and volatile organic matter. Here, carbonization in KOH/Na

Forced aeration is one of the promising ways to accelerate landfill reclamation, and understanding the relation between aeration rates and waste properties is the prerequisite to implementing forced aeration under the target of energy saving and carbon reduction. In this work, landfill reclamation processes with forced aeration were simulated using aged refuses (ARs) of 1, 4, 7, 10, and 13 disposal years, and the potential of field application was also investigated based on a field project, to identify the degradation rate of organic components, the O2 consumption efficiency and their correlations to microbes. It was found that the removal rate of organic matters declined from 20.3% (AR1) to 12.6% (AR13), and that biodegradable matter (BDM) decreased from 5.2–2.4% at the set aeration rate of 0.12 L O2/kg DM/day, respectively. A linear relationship between degradation rate constant (K) of BDM and disposal ages (x) was established: K=-0.0002193x + 0.0091 (R2 = 0.854), suggesting that BDM might be a suitable indicator to reflect the stabilization of ARs. The cellulose/ lignin ratio decrease rate for AR1 (18.3%) was much higher than AR13 (3.1%), while the corresponding humic-acid/ fulvic-acid ratio increased from 1.44 to 2.16. The dominant bacteria shift from Corynebacterium (9.2%), Acinetobacter (6.6%), and Fermentimonas (6.5%), genes related to the decompose of biodegradable organics, to Stenotrophomonas (10.2%) and Clostridiales (3.7%), which were associated with the humification. The aeration efficiencies of lab-scale tests were at the range of 5.4–11.8 g BDM/ L O2 for ARs with disposal ages of 1–13 years, and in situ landfill reclamation, ARs with disposal age of 10–18 years were around 1.9–8.8 g BDM/ L O2, as the disposal age decreased. The increased discrepancy was observed in ARs of lab-scale and field scale, indicating that the forced aeration rate should be adjusted based on aged refuses and the unit compartment combined, to reduce the operation cost.

Influent loading determines the performance of leachate treatment plant (LTP) facing the dynamic conditions, but enzyme expression in microbial community is unclear. Here, six nitrogen-metabolizing enzymes were detected during nitrification failures (NF), high loading (HL), low loading (LL), and low carbon/nitrogen (LCN) in a 500 m

Microplastics are generated from plastic waste in landfills due to physical, chemical, and biological effects, and eventually enter into the leachate. Leachate is a potential source of environmental microplastics which has not been emphasized. Here, we summarized the investigation of microplastics in leachate in 9 countries from 28 papers, provided a comprehensive review of the sampling, detection, and separation of microplastics in leachate, and elaborated on the quality control in each process. There are more than forty types of microplastics in leachate, with diverse shapes, wide size distribution, and concentrations of 0–25 items/L. Commonly used techniques are FTIR, Raman, SEM, and py-GC–MS for characterizing microplastics, while standardization of micro- or nanoplastics for leachate with a complex composition should be further studied. We also discussed in depth the degradation mechanism of microplastics in advanced oxidation processes (AOPs). Microplastics can be decomposed into small molecules such as aldehydes and ketones, and some can even eventually be degraded into CO2 and H2O in AOPs, which may be further implemented in leachate treatment plants. This review provides the scientific fundamentals for understanding the microplastics in landfill leachate and proposes removal strategies for future research.

Concentrated leachate (CL), characterized with high content salts and compositional complexity of dissolved organic matter (DOM), is difficult to degrade. Understanding the CL from molecular insight level is the requirement for further disposal based on their components. Here, typical CL samples were collected from the multi-stage membrane separation process in a large-scale leachate plant, including nanofiltration (NF), primary ultrafiltration (PUF), secondary nanofiltration (SNF), and reverse osmosis (RO). More than 95% of DOM was removed from raw CL, of which about 3/4 flowed into PUFCL and 1/5 flowed into SNFCL. DOM with macro-molecular weight (500 Da, 30.46%) and highly unsaturated compounds (double-bond equivalents15) were detected in PUFCL. Nearly half of DOM was CHO-only compounds (42.04%) in SNFCL. PUFCL was abundant in heteroatom species with higher-order oxygen (O ≥ 10), which was coincident with the trend of humic substance distribution (humic substance1/2). Based on these properties results, advanced oxidation processes, such as ozonation, might be the right process for SNFCL rich in heteroatom species with low-order oxygen (O 10). Abundant disulfides (S

To utilize carbon source and decompose the petroleum hydrocarbon substances simultaneously, adding the electrolysis to ozonation (E

The explosive increase of construction and demolition waste (CDW) caused the insufficient source separation and emergency disposal at domestic waste landfills in many developing countries. Some organic fractions were introduced to the CDW landfill process and resulted in serious odor pollution. To comprehensively explore the impacts of organic matters on odor emission patterns, five CDW landfills (OIL), with organic matters/ inert CDW components (O/I) from 5% to 30%, and the control group only with inert components (IL) or organics (OL) were simulated at the laboratory. The chemical and olfactive characters of odors were evaluated using the emission rate of 94 odorants content (ERtotal), theory odor concentration (TOCtotal), and e-nose concentration (ERENC), and their correlations with waste properties were also analyzed. It was found that the main contributors to ERtotal (IL: 93.0% NH3; OIL: 41.6% sulfides, 31.0% NH3, 25.9% oxygenated compounds) and TOCtotal (IL: 64.1% CH3SH, 28.2% NH3; OIL: 71.7% CH3SH, 24.8% H2S) changed significantly. With the rise of O/I, ERtotal, TOCtotal, and ERENC increased by 10.9, 20.6, and 2.1 times, respectively. And the organics content in CDW should be less than 10% (i.e., DOC ER ENC − (r=0.86, 0.86, -0.88, p TOC total − (r=0.82, 0.79, -0.82, p ER ENC − vs. TOC total − , r=0.96, p ER total − , r=0.86, p

The performance of electricity generation and organic wastewater degradation are two important indicators to evaluate photocatalytic fuel cell (PFC). However, data related to the impact of sulfite, especially few sulfite replenishment on PFC properties are scare. In this paper, a porous sheet-like BiVO4 photoanode was first prepared and then a self-biasing BiVO4-Au/BJS (BJS: buried junction silicon) PFC is constructed. The results show that the BiVO4 film exhibited an optimal water splitting photocurrent density of 1.15 mA cm-2 at 1.23 V vs. RHE. The PFC system can be operated without any external bias and showed high converting performance of organic into electricity. With the total addition of only 2 mM sulfite, a short-circuit current density of 0.61 mA cm−2, which is obviously higher than the BiVO4-Au/BJS system without sulfite, was obtained with maximum power output of 6.5 × 10−4 W cm−2 in 10 mg L−1 methyl orange. Furthermore, a removal ratio of 93.78% after 2 h was achieved with stable current output in the degradation process, compared with the removal ratio of 40.63% without sulfite. More importantly, TOC removal ratio also increased sharply from 30.2% to 85.4%. EPR test demonstrates that radicals including •OH and •SO4− cogenerated in system.

Untreated low methane (CH4) content (less than 10%) landfill gas within the post-methanogenic stage is currently vented into the atmosphere, constituting an important source of anthropogenic greenhouse gas (GHG). Development of a proper mitigation process for low CH4 gas is therefore necessary for landfills. In this study a special photocatalyst, Y2O3:Er3+-TiO2-0.05% graphene (GR), was synthesized by sol-gel method and then characterized; it showed a good response to visible-near-infrared (Vis–NIR) sunlight. The corresponding absorption edge was 354 nm, and upconversion fluorescence peaks of ultraviolet (364 nm) and violet (408 nm) emissions were acquired under 980 nm excitation. Y2O3:Er3+-TiO2-GR was developed and tested for removal of low CH4 landfill gas under Vis–NIR light irradiation, and a maximum photodegradation rate of 45.1% for CH4 was obtained using the photocatalyst Y2O3:Er3+-TiO2-0.05% GR with a light intensity of 2050 mW m−2. The corresponding CH4 content decreased from 10% to 5.5%, mitigating almost half of GHG during the post-methanogenic stage. The intermediate products of CH4 degradation were CO, OH, O−, CO2 and H2O traced by in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). This research proposes a new approach for reducing the GHG effect of low CH4 content landfill gas.

The re-utilization or recycling of waste completely was a big task to build the zero-waste city, and refuse derived fuel (RDF) preparation might be a potential way to recycle those variations organic wastes from industry and municipal sector, while the chemical binder was usually employed to match the mechanical property of RDF. In this work, a green-RDF was developed using wastes with different sources directly. Resin-like industrial solid waste, i.e., automotive stamping gaskets and electronic packing wastes (AE = 56%), anaerobic digestion sludge (ADS = 24%) and industrial desiccant residue (IDR = 20%), were selected and optimized to prepare green-RDF based on the previous market survey and characteristics analysis. The extending rate (ER), impact resistance index (IRI), and lower heating value (LHV) was 17.51%, 116.67% and 6.84 MJ/kg. The combustion performance of RDF was operated through TG/DSC-MS and combustion simulator with on-line FTIR gas analyzer simultaneously. The releasing temperature range for SO2 and NOx was narrowed to 211–401 °C and 212–803 °C, with the SO2 and NOx reduction of 63% and 26%, respectively, since IDR additives contributed to fixation of them in the residues through the chemical adsorption and oxidation reduction reaction. Green-RDF might be a promising method for the energy recovery from solid waste with different sources.

The development of highly efficient and separation-free, low-cost photocatalysts have crucial prospect for sustainable wastewater treatment, because it is able to eliminate the hazards of organic pollutant with facile operation. However, the relatively high cost of previous photocatalysts highly obstructs the application of these materials. Herein, we report a cost-effective and distinct konjac/graphitic carbon nitride (KCN) aerogel, which has superior performance for advanced oxidation water treatment. The abundant porous structure of the ultralight aerogel ensures the rapid adsorption of pollutants, which is much helpful for the further photodegradation process. During the working process, the aerogel is half submerged in pollutant solution and half exposed in air, forming a distinctive gas-solid-liquid triphase system, where oxygen can be rapidly delivered into the solution via the porous channels, boosting the generation of hydroxyl and superoxide radicals. Meanwhile, the aerogel structure can separate the g-C3N4, obstruct its stacking, as well as improve the light absorption rate. The synthesis, utilization and readily biodegradable treatment of the KCN aerogels are all green and eco-friendly, which is extremely constructive for strategies to develop novel highly efficient photocatalytic materials.

The reduction in the fouling is an important way to maintain the steady operation for the nanofiltration (NF) process in leachate treatment. The fouling components from the real leachate treatment process were identified using a scanning electron microscope equipped with X-ray microanalysis (SEM-EDS), infrared spectroscopy (FTIR), atomic analysis and three-dimensional fluorescence (EEM) analysis, and the coagulation of Fe/Al/PAC was selected to reduce the potential pollutants in the leachate, to reduce the potential fouling. It was found that organic humic acid and calcium-magnesium precipitates were the main pollutants in NF fouling. The foulant layer was the result of the combination of organic matter, inorganic precipitation, colloids and microorganisms, and the colloids precipitation is more important, and should be removed in advance. PAC was found to be more efficiency to reduce the colloids and the inorganic matter, among the coagulants selection, with the chemical oxygen demand (COD) removal rate of 55.1%. The commercially available coagulant-poly aluminum chloride (PAC) was chosen as a coagulant. The removal rate of leachate reached 55.1%, and the flow rate through the membrane was increased by 35.8% under the optimum condition (pH was 5.0, PAC dosage was 100 mg/L, and the membrane pressure was 0.4 MPa). Through the pilot scale test, the effluent was connected to the microfiltration membrane and then to the nanofiltration membrane and the practical engineering application is feasible.

A low-temperature heat pump sludge drying system was constructed and experimentally studied in the present study. The initial and final moisture contents on dry basis of sludge are 1.53 and 0.2, and the drying duration is 5 h. Theoretical models for heat pump circulation and moist air circulation are established and validated with the experimental results. Based on the validated theoretical models, sensitivity analysis of evaporating temperature, condensing temperature, and air mass flow rate on the temperature and humidity of moist air at the outlet of drying closet, drying rate and specific power consumption (SPC) are carried out. The temperature of moist air at the outlet of drying closet increases with increasing evaporating temperature and condensing temperature, while decreases with increasing air mass flow rate. The drying rate decreases with increasing evaporating temperature while increases with increasing condensing temperature, and first increases and then decreases with increasing air mass flow rate. The appreciated air mass flow rate ranges between 0.8 and 1.0 kg/s, and the drying rate around 6.0 kg/10min can be achieved under these conditions. The relative humidity of moist air at the outlet of drying closet shares a similar trend with the drying rate while SPC shows a contrary trend.

Effects of peroxymonosulfate (PMS) oxidation on disintegration degree (DD) and extracellular polymeric substances (EPS) properties of waste activated sludge were investigated. A combined approach of fractionation procedure and parallel factor (PARAFAC) analysis was applied to characterize EPS of sludge. Results indicated that PMS oxidation effectively broke sludge particles, resulting in DD in total nitrogen of 39.8% at 10 mg PMS (g SS) −1 . After PMS treatment, EPS increased significantly and mostly transferred to slime layer rather than loosely bound EPS (LB-EPS), and the ratio of slime to tightly bound EPS was correlated significantly with PMS dosage. With increasing PMS dosage, polysaccharides in EPS increased, while proteins in EPS and DNA in slime EPS increased firstly and then decreased. PARAFAC analysis of excitation-emission matrix spectra showed that tryptophan-like substances in both slime and LB-EPS were greatly influenced by PMS oxidation, and humic-like fluorophores in slime EPS were positively correlated with PMS dosage.

Humic substances (HS) are a major fraction of dissolved organic matters in wastewater. The effect of HS on phosphorus removal by struvite precipitation was investigated using synthetic wastewater under different initial pH values, Mg/P molar ratios and HS concentrations. The composition, morphology and thermal properties of harvested precipitates were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM) and thermo-gravimetric analysis (TGA), respectively. It showed that inhibition effect of HS reached its maximum value of 48.9% at pH 8.0, and decreased to below 10% at pH > 9.0. The increase of Mg/P ratio enhanced phosphorus removal efficiency, and thus reduced the influence of HS on struvite precipitation. At pH 9.0, the inhibitory effect of initial HS concentration matched the modified Monod model with half maximum inhibition concentration of 356 mg L −1 , and 29% HS was removed in conjunction with struvite crystallisation. XRD analysis revealed that the crystal form of struvite precipitates was changed in the presence of HS. The morphology of harvested struvite was transformed from prismatic to pyramid owing to the coprecipitation of HS on crystal surface. TGA results revealed that the presence of HS could compromise struvite purity.

This study aims to ameliorate effects of packing carriers, filling ratio, temperature and limited aeration on hydrolysis performance in a chemical industrial park wastewater treatment plant. Illumina-MiSeq sequencing was applied to compare microbial community structure between biofilm attached on carriers and activated sludge in a full-scale hydrolysis tank. Packing carriers intensified the plentifulness of microbial community, enriched hydrolytic bacteria (Betaproteobacteria, Gammaproteobacteria, Sphingobacteria, Clostridia, Bacteroidia), and enhanced biodegradability of organics in the wastewater. Rising carriers filling ratio increased first-order kinetic constant of hydrolysis from 0.015 to 0.080 h−1, and decreased fractions inert to hydrolysis. Rising temperature stimulated enzymatic activity for hydrolysis with activation energy of 80.22 kJ/mol. Limited aeration further enriched hydrolytic bacteria, inhibited sulfate-reducing bacteria and intensified biodegradability of organic substances. Variations of fluorescent organic substances and ammonia nitrogen release during hydrolysis confirmed that hydrolysis was strengthened by packing carriers, increasing filling ratio, enhancing temperature and introducing limited aeration. Packing carriers and limited aeration were techno-economic methods for enhancing hydrolysis performance in the chemical industrial park wastewater treatment plant by enriching hydrolytic bacteria and stimulating their activities.

Evaporation has been widely applied to deal with the hazardous waste of waste lubricant oil, and around 90% distillate obtained should be further treated for the final discharge or reuse as recycled water. Waste lubricant oil distillate contained amounts of pollutants of alkanes, aliphatic amines, etc., with chemical oxygen demand of 2042–2153 mg/L. To improve the ozonation efficiency, microbubble-ozonation with elevated temperature and stable pH was employed to deal with waste lubricant oil distillate in this work. The removal rates of chemical oxygen demand and total organic carbon increased from 53.07% and 25.08% to 87.45% and 72.75%, respectively, under the condition of 45 °C and stable pH 11. Active-ozone concentration increased from 26.41 to 41.76 mg/L, and the corresponding hydroxyl radical concentration increased from 29.78 to 49.28 μg/L with and without temperature and pH control. Ozone reaction rate (k) increased by 0.019 min−1. The reduced molecular weight after treatment also increased the biodegradability of the waste lubricant oil distillate due to the enhanced degradation of alkanes, aromatics and many other organic compounds. With the elevated temperature and stable pH, microbubble ozonation efficiency increase greatly, and it could be the promising processes for the further treatment of waste lubricant oil distillate in an efficiency way.

Chemical precipitation using magnesium salt is an effective technology for recovering phosphorus and ammonium nitrogen from wastewater. Effects of pH, Mg/P ratio, stirring rate, and seed crystal (SC) dosage on phosphate removal efficiency (PRE) and average particle diameter (APD) of precipitates were investigated for reject water from sludge thickening and dewatering process in municipal wastewater treatment. Response surface methodology was applied to understand the significance and the interactive effects of reaction factors. The increases in Mg/P ratio, stirring rate, and SC dosage were in favor of phosphate removal from reject water. pH is the dominant factor for phosphate removal by magnesium, followed by Mg/P and stirring rate, while SC dosage has the least effect on PRE and APD. Kinetic analysis showed that both pH regulation and SC addition could accelerate the reaction rate. The optimum conditions were obtained at pH 10.4, Mg/P of 2.0, stirring rate of 150 rpm, and SC dosage of 26.7 mg/L,...

This paper describes a cost-effective method for phosphorus removal from reject water of sludge dewatering process by using supernatant from sludge lime stabilization (SLS) processes, which are extensively used in China. Supernatant from SLS processes contains high concentration of calcium and high alkalinity hindering COD and ammonium nitrogen removal but favoring phosphate precipitation. Effects of pH and dosing ratio between supernatant and reject water on simultaneous removal of phosphorus and organic substances were evaluated. Both pH and Ca/P ratio increased with increasing dosing ratio of supernatant and reject water. The phosphorus removal achieved 90% when dosing ratio maintained above 15%. COD and humic substances were also effectively removed from reject water by adding SLS supernatant. X-ray diffraction analysis and morphology of harvested precipitates revealed that when pH increased from 7.49 to 9.77, the crystallinity increased, and hydroxyapatite converted to tri-calcium phosphate simultaneously. This method not only saves costs for chemical precipitants, but also favors nutrient removal by increasing alkalinity for nitrification and adding carbon source for denitrification, meanwhile reduces risks of pipeline blockage in wastewater treatment plants.

Three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy and gel permeation chromatography (GPC) analysis were employed to investigate the distribution and transformation of dissolved organic matter (DOM) in the anoxic–oxic-settling-anaerobic (A + OSA) process for sludge reduction. The A + OSA process showed a good performance in nitrogen and organic pollutants removal efficiency, and reduced sludge yield by 32% under a sludge retention time of 6 h in the anaerobic sludge holding tank (SHT). Parallel factor analysis was used to assess DOM composition from EEM spectra and three fluorescent components were identified: two humic-like components and one protein-like component. In the A + OSA process, the humic-like components were difficult to degraded, while the protein-like component was easily hydrolyzed and adsorbed under anoxic conditions. The fluorescence intensities of the humic-like and protein-like components were both strengthened in the SHT owing to sludge decay under the anaerobic condition. GPC analysis of the A + OSA system showed that the majority of molecules in the influent wastewater with molecular weight (MW) in the range of >250 and 30–50 kDa were mainly transformed into small molecules with MW in the range of 30–250 and

A modified sludge process reduction activated sludge (SPRAS) technology was developed by inserting a sludge process reduction (SPR) module, composed of an aeration tank and a settler, before the activated sludge system was proposed in this study. Compared with the anaerobic/anoxic/aerobic (AAO) process, the SPRAS resulted in a remarkable decrease in sludge production by 76.6%; sludge decay owing to lengthy solids retention time (about 121.5 d) could be the major cause. During the 217-day operation, the oxidation-reduction potential (ORP) (from 54 to −198 mV) and pH (from 7.8 to 5.0) at the bottom of the SPR settler gradually decreased, and low ORP and pH were in favor of sludge reduction in the SPRAS system. The insertion of the SPR module improved the removal efficiencies of suspended solids, chemical oxygen demand and ammonium nitrogen, and total nitrogen concentration in the effluent was reduced from 23.89 ± 4.82 to 14.16 ± 3.98 mg/L by 50% influent bypassing the SPR module. These results indicated that the SPRAS process could produce much less excess sludge and guarantee better effluent quality than the AAO process.

BACKGROUND Long pipeline transportation of wastewater usually generates high concentration of sulfide; however, information on nitrification inhibition by sulfide in the anaerobic–anoxic–aerobic (AAO) process is still scarce. This study focused on how sulfide could inhibit nitrification activity in the AAO process, and the inhibitory effect of initial sulfide concentration and anaerobic exposure time on the behavior of nitrifying biomass. RESULTS The net maximum specific growth rate (μAUT-bAUT) was, respectively, 0.06 ± 0.01 and 0.31 ± 0.03 d−1 at 15 and 20°C in a full-scale AAO wastewater treatment plant for long-pipeline transported wastewater. The μAUT-bAUT was not affected by 6.2 mg L−1 sulfide under aerated condition, but reduced by 75.9% after unaerated exposure for 0.5 h. The first-order kinetic constant of sulfide inhibition under anaerobic conditions was 0.658 h−1, and half maximal inhibition concentration of sulfide on nitrification was 36.0 and 10.0 mg L−1 after 1.0 h and 1.5 h anaerobic exposure, respectively. CONCLUSION Nitrifying biomass was sensitive to the presence of sulfide under anaerobic conditions. The inhibitory reaction of sulfide on nitrifying biomass under anaerobic conditions conformed to the first-order kinetic reaction, while the effect of initial sulfide concentration on nitrification inhibition matched the modified Monod model. © 2013 Society of Chemical Industry

Odorants from municipal solid waste (MSW) were complex variable, and the screening of key offensive odorants was the prerequisite for odor control process. In this study, spatial odor emissions and environmental impacts were investigated based on a large-scale working waste transfer station (LSWTS) using waste container system, and a comprehensive odor characterization method was developed and applied in terms of the odor concentration (OC), theory odor concentration (TOC), total chemical concentration (TCC), and electric nose (EN). The detected odor concentration ranged from 14 to 28 (dimensionless), and MSW container showed the highest OC value of 28, EN of 78, and TCC of 35 (ppm) due to the accumulation of leachate and residual MSW. Ninety-two species odorants were identified, and H2S, NH3, benzene, styrene, ethyl acetate, and dichloromethane were the main contributors in the container, while benzene, m,p,x-xylene, butanone, acetone, isopropanol, and ethyl acetate were predominant in the compression surface (CS) and compression plant (CP). Side of roads (SR) and unload hall (UH) showed low odorous impact. Based on this odor list, 20 species of odor substances were screened for the priority control through the synthetic evaluation method, considering the odorants concentrations, toxicity, threshold values, detection frequency, saturated vapor pressure, and appeared frequency. Graphical abstract.

The advanced oxidation technology, ferrous ion (Fe(II)) activated persulfate (PS) producing sulfate radicals, was used for the advanced treatment of effluent from an integrated wastewater treatment plant in a papermaking industrial park. Separate and interactive effects of PS dosage, Fe(II)/PS ratio and initial pH on chemical oxygen demand (COD) removal were analyzed by the response surface methodology (RSM). The results showed that Fe(II)-PS system was effective in COD removal from the secondary effluent. PS dosage was the most dominant factor with positive influence on COD removal, followed by initial pH value. The optimum conditions with COD removal of 54.4% were obtained at PS/COD of 2.2, initial pH of 6.47 and Fe(II)/PS of 1.89. UV-visible spectrum analysis showed that after RSM optimization, Fe(II)-PS system effectively degraded large organic molecules into small ones, and decreased humification degree of the effluent. Three-dimensional fluorescence analysis demonstrated that aromatic protein and fulvic substances were fully decomposed by the Fe(II)-PS treatment.

As a modified configuration of the conventional anaerobic/anoxic/aerobic (AAO) process, a novel anoxic/anaerobic/aerobic (Reversed AAO, RAAO) process has been extensively applied in domestic wastewater treatment plants (WWTP). In this study, the Activated Sludge Model No. 2d (ASM2d) and a secondary clarifier model were calibrated and applied to simulate a pilot-scale RAAO test and evaluate the operational performance of the RAAO process. For calibration of the biological model ASM2d, only four kinetic parameters were adjusted to accurately simulate in-process variations of ammonium, nitrate and phosphate. Simulation results by the calibrated model demonstrated that phosphorus accumulating organisms (PAO) in the RAAO process (0.243 gP·(gCOD)−1) contains less poly-phosphate than the AAO process (0.266 gP·(gCOD)−1). With the increasing mixed liquor recirculation ratio in the RAAO process, the fraction of heterotrophic biomass and autotrophic biomass both increased, whereas the PAO decreased owing to adverse effects of electron acceptors on phosphorus release and poly-hydroxy-alkanoates synthesis.

A sludge process reduction activated sludge (SPRAS) system by inserting a sludge process reduction (SPR) module, composed of a micro-aerobic tank and a settler, before activated sludge process was operated for sludge in situ reduction. The average removal efficiencies of COD and ammonium nitrogen were 86.6% and 87.9%, respectively. Compared to anoxic/aerobic (AO) process, SPRAS process reduced sludge production by 57.9% with observed sludge yield of 0.076 gVSS/gCOD. Pyrosequencing analyses revealed that the relative abundance and stability of microbial communities in SPRAS system were higher than AO system. Fermentative acidogenic classes Anaerolineae, Actinobacteria, Cytophagia and Caldilineae were enriched in the SPR module and responsible for sludge reduction. Specific comparison down to the genus level identified the enrichment of oxyanion-reducing bacteria (Sulfuritalea; Azospira; Ramlibacter), fermentative acidogenic bacteria (Propionivibrio; Opitutus; Caldilinea), slow growers (Ramlibacter) and predatory bacteria (Myxobacteria) in SPRAS system. Nitrifiers were also more abundant in SPRAS system than AO system.

Phosphonate is a commonly used corrosion and scale inhibitor for a circulating cooling water (CCW) system. Its discharge could cause eutrophication of receiving waters. The iron–carbon (Fe/C) micro-electrolysis technology was used to degrade and remove phosphonate from discharged CCW. The influences of initial pH, Fe/C ratio (FCR) and temperature on phosphonate removal were investigated in a series of batch tests and optimized by response surface methodology. The quadratic model of phosphonate removal was obtained with satisfactory degrees of fitness. The optimum conditions with total phosphorus removal efficiency of 95% were obtained at pH 7.0, FCR of 1.25, and temperature of 45 °C. The phosphonate removal mechanisms were also studied. Phosphonate removal occurred predominantly via two consecutive reactive phases: the degradation of phosphonate complexes (Ca–phosphonate) and the precipitation of Fe/C micro-electrolysis products (PO43−, Ca2+ and Fe3+).

Etanercept, a TNF receptor 2-Fc fusion protein, is currently being used for the treatment of rheumatoid arthritis (RA). However, 25% to 38% of patients show no response which is suspected to be partially due to insufficient affinity of this protein to TNFα. By using computational protein design, we found that residue W89 and E92 of TNFR2 were critical for ligand binding. Among several mutants tested, W89Y/E92N displayed 1.49-fold higher neutralizing activity to TNFα, as compared to that of Etanercept. Surface plasmon resonance (SPR) based binding assay revealed that the equilibrium dissociation constant of W89Y/E92N to TNFα was 3.65-fold higher than that of Etanercept. In a rat model of collagen-induced arthritis (CIA), W89Y/E92N showed a significantly better ability than Etanercept in reducing paw swelling and improvement of arthritic joint histopathologically. These data demonstrate that W89Y/E92N is potentially a better candidate with improved efficacy in treating RA and other autoimmune diseases., Author Summary Rheumatoid arthritis (RA) is a frequently occurring, chronic, debilitating disease. TNFα plays a pivotal role in regulating its inflammatory response. TNFα inhibition with TNF receptor 2-Fc fusion protein (TNFR2-Fc) was effective in the treatment of RA. However, quite a few patients may not achieve good clinical outcomes after TNFR2-Fc therapy, and the high dosage of TNFR2-Fc in clinical treatment usually causes some side effects, such as injection site reactions. Enhancing the affinity of TNFR2-Fc to TNFα would be of benefit to its therapeutic effect on RA, and may reduce the clinical dosage. We modeled the interactions of TNFα and TNFR2, and figured out the sites that may be critical for ligand-receptor binding. A high affinity TNFR2-Fc variant (E92N/W89Y) was obtained by rational mutagenesis at residue 89 and 92. It shows significant improvements compared with wild type TNFR2-Fc in suppressing rat arthritis induced by collagen. This variant is more potent in neutralizing TNFα, and thereafter may offer a higher degree of RA symptom relief, and be in a much lower dosage.

Lymphotoxin alpha (LTalpha) was first identified as a direct anti-tumor factor, whereas increasing evidence has recently shown that in most cases the growth inhibition mediated by LTalpha requires the synergistic action of other factors, such as RNA transcription or protein synthesis inhibitor. In this study, we evaluated the combined effects of LTalpha and ten chemotherapeutic drugs on cell growth in a panel of human epithelial tumor cells, and explored the molecular mechanism of their mutual action. The results showed that platinums (cisplatin, carboplatin, oxaliplatin) are more universally effective than other chemotherapeutic drugs (doxorubicin, epi-doxorubicin, 5-flourouracil, mitomycin, cyclophosphamide, vincristine and vinorelbine) to enhance the response of six human epithelial tumor cell lines (A375, Bcap37, NCI-H157, SW480, BGC-823 and HeLa) to LTalpha. A systemic treatment with a combination of LTalpha and cisplatin in a human Bcap37 breast cancer xenograft nude mice model dramatically improved the therapeutic efficacy of LTalpha. Further analysis revealed that the sensitization of platinums was associated with platinums-induced suppression of nuclear factor-kappaB (NFkappaB) and subsequent downregulation of X-linked inhibitor of apoptosis protein (XIAP), which rescued caspase-3 from inhibition. Our results suggested that a proper combination of bio-agents such as LTalpha and conventional chemotherapeutic drugs such as platinums may be an efficient treatment strategy for human epithelial cancers.