In this study, a bio-composite (IBWS700) was prepared using inorganic phosphate-solubilizing bacteria (iPSB), which were immobilized on biochar produced from wheat straw (WS700). Further, the bio-remediation effects of the composite for lead (Pb) in soil were also investigated. The presence of different Pb species, physicochemical properties, enzyme activities, and immobilization mechanisms of Pb in soil were also evaluated. Compared to free iPSB and biochar, IBWS700 significantly decreased the lead bio-availability whereas increased the residual fraction, also affected available phosphorus (AP), cation exchange capacity (CEC), organic matter (OM) and activity of urease, alkaline phosphatase, sucrase and catalase. Interestingly, the changes in the enzyme activity, AP and OM performed twice increases with increasing Pb concentration, which was rarely reported. The reason might be attributed to the reconstruction of bacteria communities with high Pb load. Further, the immobilization mechanisms mainly included bio-adsorption and bio-precipitation. SEM revealed that the surface of IBWS700 covered with a large number of heterogeneous colonization of iPSB and white stack after Pb2+ adsorption. FTIR spectra showed that O-H, C-O-P, CO, and C =C could play important roles in bio-adsorption. Moreover, XRD analysis indicated that bio-precipitates were mainly Pb5(PO4)3Cl. In general, the use of IBWS700 could effectively immobilize Pb2+ and improve soil quality.

A pilot-scale anaerobic membrane bioreactor (AnMBR) was operated for 435 days in this study, aiming to treat pharmaceutical solvent wastewater containing m-Cresol (MC), isopropanol (IPA) and N,N-Dimethylformamide (DMF) pollutants at different temperatures of 35 +/- 3 degrees C, 25 +/- 3 degrees C, 15 +/- 3 degrees C and 25 +/- 3 degrees C, respectively. The reactor reached average total removal efficiencies of about 96%, 97.2% and 98% of MC, IPA and DMF at psychrophilic condition (15 +/- 3 degrees C). Higher physical removal rate was obtained at 15 +/- 3 degrees C due to the important contribution of membrane filtration. At this stage, the biogas production, methane content and specific methanogenic activity and extracellular polymeric substances of suspended sludge were observed with the lowest level. Moreover, the kinetic models for solvent degradation were established at different temperatures, results showed the smaller maximum specific substrate degradation rate of MC and IPA, besides, the lowest degradation rate of three solvents were obtained at 15 +/- 3 degrees C.

In this study, a pilot scale anaerobic membrane bioreactor (AnMBR) was operated for 80 days to treat pharmaceutical wastewater containing m-cresol (MC) and iso-propyl alcohol (IPA). The aim of the study is to investigate the performance and methane fermentation characteristics of AnMBR at different hydraulic retention time (HRT) (48, 36, 24, 18 and 12 h). The average total removal efficiencies of MC and IPA were 95%, 96% during the 80 days, which demonstrated that the AnMBR system performed well in the MC and IPA removal. The major volatile fatty acid (VFA) was found to be acetic acid, propionic acid, butyric acid, besides, the VFA accumulated apparently when HRT decreased to 12 h. The decrease of HRT led to an increase of relative abundance of methanosarcina from 13 to 33% and a decrease in biogas yield from 0.19 to 0.05 L/gCODremoval. The biogas production was found to increase dramatically at HRT of 36 h. The trend of methane content kept stable at this stage with the average value of 78.5% which higher than other HRTs. The investigation of methanogen community showed that methanosarcinaceae was always dominant acetoclastic methanogens and methanomicrobiales was the dominant hydrogen utilizers throughout the operational period. When the HRT dropped to 12 h, the growth of the methanosarcinaceae and methanomicrobiales was observed, the amount of the methanosarcinaceae and methanomicrobiales sharply increased. After the overall research, HRT of 36 h was chosen as the most suitable operating condition due to the comprehensively preferable performance and more economical.

The performance of a pilot-scale anaerobic membrane bioreactor (AnMBR) for treating antibiotic solvent wastewater under different cross flow velocities (CFV) was investigated. Effects of mixed liquid suspended solids (MLSS), colloid total organic carbon (TOC) and CFV on membrane fouling rate (R-MF ) were also explored in this paper. Throughout 341 days of experiment, the average total removal rate of N, N-Dimethylformamide (DMF) was 98.5% which hardly affected by the variation of CFV, and the compliance rate of DMF was 92% according to the Chinese standard (<25 mg/L). However, the relevant high total removal rate of M-cresol (MC) was achieved as 97.5%, the content of effluent failed to meet the national level emission standard (<0.1 mg/L). The biogas yield and the methane content of the biogas increased gradually with the increase of CFV, and the average methane content were over 70%. There were four kinds of methanogens in AnMBR, Methanosaeta spp was the largest methanogenic community, with an area of 45-70% of the archae. There was a linear relationship between colloid TOC and R-MF at different MLSS concentrations. Then a universal mathematical model for the changes of R-MF with influence factors was established. The result showed that model well fitted the laboratory data. It is suggested that the model proposed could reflect and manage the membrane fouling of AnMBR treating antibiotic solvent wastewater. (C) 2018 Elsevier Ltd. All rights reserved.

This study focuses on the effects of organic loading rate (OLR) on the removal of N,N-Dimethylformamide(DMF), m-Cresol (MC) and isopropyl alcohol (IPA) by a pilot-scale anaerobic membrane bioreactor (AnMBR) for treating chemical synthesis-based antibiotic solvent wastewater at period of improved influent COD concentration with decreased HRT. The whole process was divided into five stages in terms of the variation of OLR ranging from 3.9 to 12.7 kg COD/(m3·d). During 249 days of operating time, the average DMF, MC, IPA removal efficiency were 96.9%,98.2% and 96.4%, respectively. Cake layer was accumulated on the membrane surface acted as a dynamic secondary biofilm which lead to the increase of physical removal rate. In addition, mathematical statistical models was built on the linear regression techniques for exploring the inner relationship between EPS and the performance of the AnMBR.

This study aims at evaluating the performance and microbial community dynamics of anaerobic membrane bioreactor (AnMBR) treating antibiotic solvent wastewater at improved influent quality period. The whole process was divided into five phases according to the influent COD concentration with a fluctuated volume loading rate (VLR) ranging from 3.9 to 12.7kgCOD/(m3·d). After 249days of operation, the average COD and THF removal efficiency were 93.6% and 98.7%, respectively. The accumulation of VFA, relatively low pH, decline of biogas production and methane content were discovered at higher VLR (>10kgCOD/(m3·d)). Methanomicrobiales are the major population throughout the whole running period. Methanosaetaceae showed a minor relative abundance compared both of them, while Methanobacteriales remained a minimum value. Results showed that the reactor performed an excellent pollutants removal effect because of the function of membranes even at high VLR conditions.

The performance of a new pilot split-type anaerobic membrane bioreactor (AnMBR) configuration for treating antibiotics solvent wastewater at low temperatures was evaluated in this study. The AnMBR system comprised an internal circulation (IC) and ultrafiltration membrane modules, working as the biological removal and physical retention, respectively. The whole process was divided into four stages in terms of the variation of temperatures (35±3°C, 25±3°C, 15±3°C, 25±3°C). Total chemical oxygen demand (CODtotal) and tetrahydrofuran (THFtotal) removal efficiency at temperatures as low as 15±3°C were similar to mesophilic conditions (35±3°C, 25±3°C), which achieved over 95% and 96%, respectively. While different mechanism of removal was obtained at different temperatures. The excellent removal efficiency was maintained via the combination of biological and physical removal, biological removal was the major reason of removal efficiency (>83.3%) at mesophilic temperatures and physical removal (>38.6%) dominated the effect at lower temperatures. As temperature decreased, permeate volatile fatty acids (VFA) in the bioreactor accumulated suggesting a reduction of methanogens activity and pH had a minimum value of 6.5. However, neither of them showed significant sign of water degradation towards the end of experiment. The examination of alkalinity, α value, and end-products of anaerobic fermentation, MLSS, MLVSS and MLVSS/MLSS suggested a negative effect slightly on microbial activity and no negative effect on the effluent quality at low temperatures due to the retention of membrane.

Tetrahydrofuran (THF) is one of the most representative characteristics of pollutant in pharmaceutical industry usually has high biological toxicity, making it difficult to treat. In this study, a pilot scale anaerobic membrane bioreactor (AnMBR) was employed to treat THF pharmaceutical wastewater under different hydraulic retention time (HRT). During the 80-day operating time, chemical oxygen demand (COD) and THF removal efficiencies reached 95.3% and 98.5% when HRT was above 24h. Mixed liquid suspended solids (MLSS) and mixed liquor volatile suspended solids (MLVSS) in the attached sludge on membrane surface showed a trend of rising on first 28days (48h-36h) and then decreasing. Protein is the major component of extracellular polymeric substances (EPS) independent of changes in HRT. The study concludes that THF pharmaceutical wastewater can be effectively remedied in the AnMBR system at low HRT.

The effect of high cross flow velocity (CFV) on the operational efficiency of a pilot-scale anaerobic membrane bioreactor (AnMBR) treating antibiotic solvent effluents was explored. The average of total Chemical Oxygen Demand (COD) and tetrahydrofuran (THF) removal efficiencies during four Runs were 96.5% and 98.7%. Meanwhile, biological removal contributions were 74.3% and 78%, the rest part was attributed by the physical removal process of the membrane block, VFA (Volatile Fatty Acids) and alpha value (VFA/alkalinity) increased with the increase of CFV, resulted alkalinity decreased. Biomass concentration mixed liquid suspended solids (MLSS) and mixed liquor volatile suspended solids (MLVSS) as well as the polysaccharide increased smoothly in the suspended sludge with the CFV increasing, and the protein content decreased gradually. However, the concentration of biomass, polysaccharide and protein presented opposite trends in the attached sludge of the membrane. The results indicated that AnMBR can effectively treat the antibiotic solvent wastewater under high CFV.

In this study, wheat straw (WS) and dairy manure (DM) were ultrasonically pretreated to optimize the time for ultrasonic pretreatment (UP), identify the most appropriate optimization method, clarify whether UP is a high efficiency method for application, and explain why UP improves total methane production (TMP). The pretreatment conditions were designed using orthogonal experiment design (OED) and central composite design (CCD) and were optimized using the direct measurement method and response surface method, the relationships among the initial digestion characteristics and TMP were subsequently analyzed, the net energy, and energy benefit were calculated. The OEM results showed that mixed DM pretreated for 30 minutes (min) and WS pretreated for 20 min (DM30WS20) produced the maximum TMP, net energy, and energy benefit of 186 mL/g TS (total solid), 6.04 kJ/g TS, and 2.88 kJ/g TS, respectively. For CCD, the maximum TMP, net energy, and energy benefit were 146.61 mL/g TS, 4.91 kJ/g TS, and 1.75 kJ/g TS, respectively, and were obtained with DM9WS25. The maximum TMP, net energy, and energy benefit of OED were greater than those of CCD, indicating that OED is more suitable for UP in anaerobic digestion (AD). When pretreated with UP, the surface of DM showed an increasingly uniform distribution and WS became increasingly rough and displayed fractures of different degrees. Cellulose activity contributed the maximum (0.3856) direct decision influence to TMP, and the comprehensive decision influence at a pH of 0.328 was the highest in TMP. This study concluded that the direct measurement, method in OED was best suited for the design and optimization of pretreatment conditions by UP in AD. UP improved TMP, net energy, and energy benefit by changing the initial environment of AD. Therefore, UP is a high-energy benefit method and worth popularizing for AD. (C) 2016 Elsevier Ltd. All rights reserved.

To solve the problem of core fracture and loose during casting process,tests were carried out,and the effects of pouring temperature,mold shell temperature,casting speed,pouring system and casting grain size on casting core fracture was studied.A kind of gating system has been designed,which can effectively prevent the molten steel impact on the core.The result shows that increasing the shell temperature and reducing the pouring velocity are beneficial to grain refinement and preventing the molten steel impact breakage.It is effective to reduce the casting core fracture by bottom gating system and intersection type feeding system.It has proved that the casting process can effectively improve the qualified rate of the casts.

In this paper,through design and research on gating system for production of directional solidified low pressure turbine blade,the factors of gating system,which have a great influence on the quality of directional solidified casting,have been confirmed and studied,and process with a higher cast yield has been determined.The results show that,in the design of gating system,the blades distribution mode and seeding position have a direct influence on the growth of columned grains and compactness of microstructure of the directional solidified blade.Uniform distribution in ring shape of blades benefits the growth of columned grains along direction,however,the sector distribution of blades has negative influence on growth of columned grains.

Self thinning is a phenomenon of the mortality of some individuals caused by intraspecific competition. The researches on self thinning pure stands for 40 years in the world were summarized and evaluated including self thinning rule, allometric model, mean individual weight density trajectory during the course of self thinning, species self thinning line and dynamic thinning line, the relationship between the slope of self thinning line and biomass, the relationship between the self thinning and competition density effect, and self thinning mechanism.