Innovative sponge-based moving bed-osmotic membrane bioreactor hybrid system using a new class of draw solution for municipal wastewater treatment

© 2016 Elsevier Ltd. For the first time, an innovative concept of combining sponge-based moving bed (SMB) and an osmotic membrane bioreactor (OsMBR), known as the SMB-OsMBR hybrid system, were investigated using Triton X-114 surfactant coupled with MgCl2 salt as the draw solution. Compared to traditional activated sludge OsMBR, the SMB-OsMBR system was able to remove more nutrients due to the thick-biofilm layer on sponge carriers. Subsequently less membrane fouling was observed during the wastewater treatment process. A water flux of 11.38 L/(m2 h) and a negligible reverse salt flux were documented when deionized water served as the feed solution and a mixture of 1.5 M MgCl2 and 1.5 mM Triton X-114 was used as the draw solution. The SMB-OsMBR hybrid system indicated that a stable water flux of 10.5 L/(m2 h) and low salt accumulation were achieved in a 90-day operation. Moreover, the nutrient removal efficiency of the proposed system was close to 100%, confirming the effectiveness of simultaneous nitrification and denitrification in the biofilm layer on sponge carriers. The overall performance of the SMB-OsMBR hybrid system using MgCl2 coupled with Triton X-114 as the draw solution demonstrates its potential application in wastewater treatment

Shared-aperture dual-band dual-polarization array using sandwiched stacked patch

An L/C dual-band dual-polarized (DBDP) shared aperture microstrip array is proposed in the paper. In the array, the sandwiched stacked patch is employed for the L-band element to exploit the bandwidth for given element thickness. Several key issues regarding the proposed structure are discussed, including: 1) benefit of proposed L band sandwiched stacked patch; 2) C-band feeding method; 3) radiation performance in both bands. A prototype array of L/C DBDP sandwiched stacked patch is designed and fabricated to verify the feasibility of the proposed structure, where the measured data are presented in the paper. © 2010 EMW Publishing. All Rights Reserved

A novel osmosis membrane bioreactor-membrane distillation hybrid system for wastewater treatment and reuse

© 2016 . A novel approach was designed to simultaneously enhance nutrient removal and reduce membrane fouling for wastewater treatment using an attached growth biofilm (AGB) integrated with an osmosis membrane bioreactor (OsMBR) system for the first time. In this study, a highly charged organic compound (HEDTA3-) was employed as a novel draw solution in the AGB-OsMBR system to obtain a low reverse salt flux, maintain a healthy environment for the microorganisms. The AGB-OsMBR system achieved a stable water flux of 3.62 L/m2 h, high nutrient removal of 99% and less fouling during a 60-day operation. Furthermore, the high salinity of diluted draw solution could be effectively recovered by membrane distillation (MD) process with salt rejection of 99.7%. The diluted draw solution was re-concentrated to its initial status (56.1 mS/cm) at recovery of 9.8% after 6 h. The work demonstrated that novel multi-barrier systems could produce high quality potable water from impaired streams

Applicability of an integrated moving sponge biocarrier-osmotic membrane bioreactor MD system for saline wastewater treatment using highly salt-tolerant microorganisms

© 2017 Elsevier B.V. Osmotic membrane bioreactors (OsMBRs) are a recent breakthrough technology designed to treat wastewater. Nevertheless, their application in high-salinity wastewater treatment is not widespread because of the effects of saline conditions on microbial community activity. In response, this study developed an integrated sponge biocarrier-OsMBR system using highly salt-tolerant microorganisms for treating saline wastewater. Results showed that the sponge biocarrier-OsMBR obtained an average water flux of 2 L/m2 h during a 92-day operation when 1 M MgCl2 was used as the draw solution. The efficiency in removing dissolved organic compounds from the proposed system was more than 99%, and nutrient rejection was close to 100%, indicating excellent performance in simultaneous nitrification and denitrification processes in the biofilm layer on the carriers. Moreover, salt-tolerant microorganisms in the sponge biocarrier-OsMBR system worked efficiently in salt concentrations of 2.4%. A polytetrafluoroethylene MD membrane (pores = 0.45 μm) served to regenerate the diluted draw solution in the closed-loop system and produce high-quality water. The moving sponge biocarrier-OsMBR/MD hybrid system demonstrated its potential to treat salinity wastewater treatment, with 100% nutrient removal and 99.9% conductivity rejection

Online support vector machine application for model based fault detection and isolation of HVAC system

Abstract—Preventive maintenance plays an important role in Heating, Ventilation and Air Conditioning (HVAC) system. One cost effective strategy is the development of analytic fault detection and isolation (FDI) module by online monitoring the key variables of HAVC systems. This paper investigates realtime FDI for HAVC system by using online Support Vector Machine (SVM), by which we are able to train a FDI system with manageable complexity under real time working conditions. It is also proposed a new approach which allows us to detect unknown faults and updating the classifier by using these previously unknown faults. Based on the proposed approach, a semi unsupervised fault detection methodology has been developed for HVAC system

Typical lignocellulosic wastes and by-products for biosorption process in water and wastewater treatment: A critical review

Biosorption on lignocellulosic wastes and by-products has been identified as a proper alternative to the existing technologies applied for toxic metal ion and dye removal from wastewater streams. This paper deals with utilization of typical low cost wastes and by-products produced in different food agricultural and agro-industries as biosorbent and reviews the current state of studies on a wide variety of cheap biosorbents in natural and modified forms. The efficiency of each biosorbent has been also discussed with respect to the operating conditions (e.g. temperature, hydraulic residence time, initial metal concentration, biosorbent particle size and its dosage), chemical modification on sorption capacity and preparation methods, as well as thermodynamics and kinetics. © 2013 Elsevier Ltd

Analysis and attribution of total column ozone changes over the Tibetan Plateau during 1979–2017

Various observation-based datasets have confirmed positive zonal mean column ozone trends at midlatitudes as a result of the successful implementation of the Montreal Protocol. However, there is still uncertainty about the longitudinal variation of these trends and the direction and magnitude of ozone changes at low latitudes. Here, we use the extended Copernicus Climate Change Service (C3S) dataset (1979–2017) to investigate the long-term variations in total column ozone (TCO) over the Tibetan Plateau (TP) for different seasons. We use piecewise linear trend (PWLT) and equivalent effective stratospheric chlorine loading (EESC)-based multivariate regression models with various proxies to attribute the influence of dynamical and chemical processes on the TCO variability. We also compare the seasonal behaviour of the relative total ozone low (TOL) over the TP with the zonal mean at the same latitude. Both regression models show that the TP column ozone trends change from negative trends from 1979 to 1996 to small positive trends from 1997 to 2017, although the later positive trend based on PWLT is not statistically significant. The wintertime positive trend starting from 1997 is larger than that in summer, but both seasonal TP recovery rates are smaller than the zonal means over the same latitude band. For TP column ozone, both regression models suggest that the geopotential height at 150 hPa (GH150) is a more suitable and realistic dynamical proxy compared to a surface temperature proxy used in some previous studies. Our analysis also shows that the wintertime GH150 plays an important role in determining summertime TCO over the TP through persistence of the ozone signal. For the zonal mean column ozone at this latitude, the quasi-biennial oscillation (QBO) is nonetheless the dominant dynamical proxy. We also use a 3-D chemical transport model to diagnose the contributions of different proxies for the TP region. The role of GH150 variability is illustrated by using two sensitivity experiments with repeating dynamics of 2004 and 2008. The simulated ozone profiles clearly show that wintertime TP ozone concentrations are largely controlled by tropics to midlatitude pathways, whereas in summer variations associated with tropical processes play an important role. These model results confirm that the long-term trends of TCO over the TP are dominated by different processes in winter and summer. The different TP recovery rates relative to the zonal means at the same latitude band are largely determined by wintertime dynamical processes

Influences of operational parameters on phosphorus removal in batch and continuous electrocoagulation process performance

© 2017, Springer-Verlag GmbH Germany. Performance of an electrocoagulation (EC) process in batch and continuous operating modes was thoroughly investigated and evaluated for enhancing wastewater phosphorus removal under various operating conditions, individually or combined with initial phosphorus concentration, wastewater conductivity, current density, and electrolysis times. The results revealed excellent phosphorus removal (72.7–100%) for both processes within 3–6 min of electrolysis, with relatively low energy requirements, i.e., less than 0.5 kWh/m3 for treated wastewater. However, the removal efficiency of phosphorus in the continuous EC operation mode was better than that in batch mode within the scope of the study. Additionally, the rate and efficiency of phosphorus removal strongly depended on operational parameters, including wastewater conductivity, initial phosphorus concentration, current density, and electrolysis time. Based on experimental data, statistical model verification of the response surface methodology (RSM) (multiple factor optimization) was also established to provide further insights and accurately describe the interactive relationship between the process variables, thus optimizing the EC process performance. The EC process using iron electrodes is promising for improving wastewater phosphorus removal efficiency, and RSM can be a sustainable tool for predicting the performance of the EC process and explaining the influence of the process variables

New sealing material for drainage operations

A new sealing material for the drainage operations from pulverized coal was investigated. Its microstructure and strength characteristics are determined. Evaluation of the quality of the test material for hermetic sealing of holes was verified in a coal mine. Experiments have shown that the concentration of drainage gas in the wellbore, which is sealed with sealing material from the pulverized-hole, is higher than when using an expensive cement material (82.50% vs. 69.65%)

A comparative study on different metal loaded soybean milk by-product 'okara' for biosorption of phosphorus from aqueous solution

Cationization of agricultural by-products using metal salts is widely used to activate their phosphorous capture ability. This study developed three kinds of new metal loaded soybean milk by-product 'okara' for phosphorus biosorption. A comparative study among these biosorbents was carried out with respect to their performances in terms of affinity, stability and reusability. Zirconium loaded okara (ZLO) was found to have the highest affinity towards PO43- anions (47.88mg/g), followed by iron/zirconium loaded okara - IZLO (40.96mg/g) and iron loaded okara - ILO (16.39mg/g). ZLO was successfully desorbed with 0.2M NaOH and activated with 0.1 HCl prior to the next cycle. After five consecutive cycles, the efficiency of both adsorption and desorption of ZLO remained about 85% whilst no Zr(IV) leakage was observed. Conversely, IZLO and ILO suffered from vital short comings such as high metal release and/or sharp reduction in PO43- sequestering capability after multi operation cycles. © 2014 Elsevier Ltd