Characterization of Anaerobic Membrane Bioreactors (AnMBR) Treating Municipal Wastewater

The study investigated the impact of solids retention time (SRT), hydraulic retention time (HRT) and the addition of FeCl3 on bioprocess and membrane performance of anaerobic membrane bioreactor (AnMBR) treating authentic municipal wastewater. The impact of SRT (40~100 days) and HRT (8.5~12.5 hours) on bioprocess performance was assessed using one pilot and one bench scale AnMBRs. The results revealed superior permeate quality with respect to concentrations of chemical oxygen demand (COD) (<40mg/L) and 5-day biochemical oxygen demand (BOD5) (<10mg/L) can be achieved in all tests. SRT and HRT did not significantly influence on the COD and BOD5 removal efficiencies. Extended SRTs had reduced sludge production and enhanced methane production. Oversaturation of dissolved methane in permeate was assumed to be responsible for a consistent lack of mass balance closure in all tests. After calibration of biokinetic coefficients, PetWin 4 (EnviroSim Canada) was found to effectively simulate particulate COD, readily biodegradable COD and acetic acid concentrations over a range of SRTs and HRTs. The long term membrane performance was evaluated when pilot AnMBR operated with varied SRT (100~40 days) and recovery cleaning. The results revealed reduced SRTs had reduced the fouling propensity of mixed liquor characteristic in terms of TSS concentration and dewaterability as indicated by colloidal COD (cCOD) concentration and capillary suction time (CST). The effect of these parameters corresponded to the short term fouling (i.e. cake accumulation) that was tested by critical flux tests. The recovery cleaning obtained efficient fouling resistance removal on both pilot plant operation and clean water flux tests. However, the long-term fouling rate was observed significantly higher on cleaned membrane than virgin membrane and appeared to be higher after each recovery cleaning regardless the varied mixed liquor characteristics. The mitigated membrane fouling with virgin membrane suggested initial membrane condition might contributed to the lack of consistency between mixed liquor and fouling as the membrane properties might be modified by residual foulants. The study on long-term (90 days) impact of dosing FeCl3 on the bioprocess performance and membrane performance was evaluated in the pilot AnMBR fed with non-Fe dosed sewage and fed with 26.0 mgFeCl3/L to the sewage.The results showed the addition FeCl3 enhanced the treatment performance of the pilot AnMBR regarding to the removal efficiencies of COD and BOD5, but did not generate significant influence on the removal efficiencies of total Kjeldahl nitrogen(TKN) and total phosphorus(TP) and the methane yield. The membrane performance was significantly improved by dosing FeCl3 which demonstrated by irreversible fouling lower than 5kPa and no reversible fouling for the first 75 days. The superior membrane performance can be correlated to the shift of particle size distribution to the particulate fraction and the reduced colloidal and soluble substances in the sludge, especially the soluble protein, carbohydrate, Ca and S. The confocal laser scanning microscopy (CLSM) tests showed with the addition of FeCl3 a thicker foulant layer was developed and the deposition of protein and carbohydrate on the membrane surface was significantly prevented. Therefore a more porous foulant layer was formed and prevented the development of strongly-attached cake layer and pore blocking. The recovery cleaning study indicated FeCl3 dosing enhanced the efficiency of current recovery cleaning protocol and the foulants formed in the Fe-dosed sludge was more of inorganic origin, as 75% of the foulant resistance was removed by citric acid. The superior membrane performance during the operation combined with enhanced cleaning efficiency by FeCl3 dosing would significantly improve the sustainability of AnMBR in municipal wastewater treatment. A transient study was conducted at pilot scale to assess the impact of Fe dosage on the dynamics of biological and membrane performance of the AnMBR. A transient model of the AnMBR system was employed to assist with interpretation of the measured responses in the mixed liquor under different FeCl3 dosages. A high dosage (43mg/L) of FeCl3 resulted in a significant accumulation of fixed suspended solids (FSS) and volatile suspended solids (VSS) and reduction of colloidal COD in the mixed liquor. The elevated dosages appeared to reduce the biodegradability of VSS that was present in the raw wastewater. Intermediate dosages of FeCl3 (21-12 mg/L), had less effect on these responses and did not appear to affect VSS biodegradation. Membrane performance was significantly affected by FeCl3 dosage as indicated by reversible and irreversible resistances. Reversible resistance was closely related to the colloidal COD in the mixed liquor, thus responded quickly to Fe dosage. Irreversible resistance had a delayed response to changes in the colloidal COD concentrations in the mixed liquor and this was attributed to the effect of slow mass transfer of colloidal matter between the mixed liquor and the membrane

Effects of the root extract of Dipsacus asperoides (Caprifoliaceae) on locomotor function and inflammation following spinal cord injury in rats

Purpose: The study was performed to determine the effect of Dipsacus asperoides (roots), commonly known as Xu Duan, on rats with spinal cord injury (SCI).Methods: All the animals were separated into 3 groups: normal control; a group that received Dipsacus asperoides treatment after spinal injury, and a group that received phosphate-buffered saline after SCI. These groups allowed for determination of the effect of Dipsacus asperoides treatment on SCI-injured rats. Evaluation of locomotor function restoration based on Basso–Beattie–Bresnahan score was carried out while expressions of I-kBα and NF-kB p65 were estimated. Evaluation of pro-apoptotic protein Bax and anti-apoptotic protein Bcl-2 levels was also carried by Western blotting and densitometry.Results: The results showed that 10-mg/kg/day dose of Dipsacus asperoides restored locomotor function in rats after a period of 4 weeks. The treatment also decreased expressions of I-kBα, NF-kB p65 and Bax, but significantly increased expression of Bcl-2 (p &lt; 0.01) in treated rats, compared to untreated rats.Conclusion: The results indicate that treatment with Dipsacus asperoides extract effectively mitigates spinal cord injury by attenuating inflammation and apoptosis in SCI rats.Keywords: Spinal cord injury, IKK-NFkB pathway, Bax, Bcl-2, Xu Duan, Apoptosi

Optimized properties of innovative ElectroChromic Device using ITO / Ag / ITO electrodes

The “Dielectric/Metal/Dielectric” (DMD) stacked films being used as transparent and conductive (TC) electrodes, have demonstrated excellent application in the ElectroChromic (EC) process and devices. In this work, multilayers (IAI) made of 50 nm of Indium Tin Oxide (ITO)/5 nm of metallic silver (Ag)/30 nm of ITO that exhibit band-gap, low resistance of 7.4 Ω and the high figure of merit of 9.9 × 10−3 Ω−1 were introduced in a complete five-layer Glass/IAI/NiOx/LiClO4-PC-PMMA/WO3/IAI/Glass ElectroChromic Device (ECD). The single IAI electrode as well as the two actives EC layers Glass/IAI/NiOx and Glass/IAI/WO3 were firstly characterized for their TC and EC properties respectively. Then, the EC properties of the complete five-layer ECD were analyzed. Fast response time (2.02 s for the bleaching and 2.25 s for complete coloration), wide optical modulation in the visible light region (∼55% at 550 nm), long lifetime (more than 6000 s), large capacity and good stability as well as high coloration efficiency (31.7 cm2 C−1) were obtained. The improved EC performance of ECD were related to the good electrical and optical properties of IAI electrode

Proximal femoral nail antirotation (PFNA) and Hemiarthroplasty in the treatment of elderly intertrochanteric fractures

Objective: To investigate reasonable treatment of intertrochanteric fractures with proximal femoral nail antirotation (PFNA) or Hemiarthroplasty (HA) in elderly patients.Methods: In January 2009 to June 2013 367 patients were admitted in our hospital. Comparison between the two methods (PFNA and Hemiarthroplasty) was done with the time duration of the surgery, intra-operative blood loss, and postoperative weight bearing time, implant complications and The Harris hip score.Results:  Results were analyzed after 50 months of follow up. In comparison of the surgical time duration between the PFNA group the Hemiarthroplasty group, Hemiarthroplasty had shorter duration of surgical time.  The intra operative blood loss of PFNA was significantly less than Hemiarthroplasty. Post operative weight bearing time was significantly shorter in Hemiarthroplasty than PFNA.  Conclusion:  For elderly patients with unstable fractures, severe osteoporosis and preoperative mobility can be preferred to Hemiarthroplasty.  The proximal femoral nail Antirotation (PFNA) for the treatment of intertrochanteric fractures has been increasingly accepted and widely used

Flexible Power Supply System of AC Electric Arc Furnace

The AC electric arc furnace (EAF) is becoming a core apparatus of the modern steel industry. Nevertheless, it used to be a major threat of power quality in the traditional power supply system. In this paper, a flexible power supply system of the AC EAF is proposed, which is expected to completely alter its inherent cognition of impact load in the power grid. The basics of the power supply for EAF are first reviewed and the novel techniques to enhance the operation flexibility of EAF are introduced. The power circuit and the control structure are then presented, followed by the detailed strategies of various operations fully considering the features of EAF. A large disturbance stability criterion based on the mixed potential theory is also established for the practical application. Both electromagnetic transient simulations using PSCAD and benefit analyses verify the feasibility of the proposed system

Tunable smart digital structure (SDS) to modularly assemble soft actuators with layered adhesive bonding

Many shape memory alloy (SMA)-based soft actuators have specific composite structures and manufacture processes, and are therefore unique. However, these exclusive characteristics limit their capabilities and applications, so in this article a soft and smart digital structure (SDS) is proposed that acts like a modular unit to assemble soft actuators by a layered adhesive bonding process. The SDS is a fully soft structure that encapsulates a digital skeleton consisting of four groups of parallel and independently actuated SMA wires capable of outputting a four-channel tunable force. The layered adhesive bonding process modularly bonds several SDSs with an elastic backbone to fabricate a layered soft actuator where the elastic backbone is used to recover the SDSs in a cooling process using the SMA wires. Two kinds of SDS-based soft actuators were modularly assembled, an actuator, SDS-I, with a two-dimensional reciprocal motion, and an actuator, SDS-II, capable of bi-directional reciprocal motion. The thermodynamics and phase transformation modeling of the SDS-based actuator were analyzed. Several extensional soft actuators were also assembled by bonding the SDS with an anomalous elastic backbone or modularly assembling the SDS-Is and SDS-IIs. These modularly assembled soft actuators delivered more output channels and a complicated motion, e.g., an actinomorphic soft actuator with four SDS-Is jumps in a series of hierarchical heights and directional movement by tuning the input channels of the SDSs. This result showed that the SDS can modularly assemble multifarious soft actuators with diverse capabilities, steerability and tunable outputs