bluuebunny/crossref_metadata_2025 huggingface dataset:
Concentration of nutrients from urine and reject water from anaerobically digested sludge
Authors: Ek M. , Bergström R. , Bjurhem J.-E. , Björlenius B. , Hellström D.
Published: February 2016

Experiments with concentration of nutrients from source separated urine and reject water from digestion of sludge in sewage treatment plants (STP) have been performed in laboratory and pilot scale. The methods tested were membrane filtration with reverse osmosis (RO), evaporation, and precipitation of phosphorus and distillation of ammonia. In membrane filtration, pre-filtration with particle separation at 5–10 μm was enough to avoid clogging of the membranes. Separation of phosphorus (P), potassium (K) and sulphur (S) was almost 100%, while separation of nitrogen (N) was dependent on pH. The capacity of flux increased with temperature and pressure. In evaporation, all P, K and S were still in the concentrate, while pH had to be decreased to 4.5 to avoid significant loss of N. In precipitation and distillation, about 90% of P could be recovered from urine as magnesium ammonium phosphate (MAP) just by adding MgO. For the reject water pH was first increased by aeration to remove CO2. Ammonium can be distilled from the water phase after precipitation of MAP, without further increase of pH. At least 80–90% of N can be distilled in 5–10% of the total volume. The article also discusses the quality of different products, cost of separation, and energy and chemical demand.
Fluxes of 13 selected pharmaceuticals in the water cycle of Stockholm, Sweden
Authors: Wahlberg C. , Björlenius B. , Paxéus N.
Published: February 2016

Mass flows of 13 pharmaceutical active ingredients (APIs) found in drinking water were studied in the water cycle of Stockholm. Data were collected by analyzing samples of surface water, raw water and drinking water as well as influents, effluents and sludges from waste water treatment plants (WWTPs) in Stockholm area. A mass balance was performed, based on sold amounts of pharmaceuticals and the measured concentrations in water and sludge. The selected APIs were all present in WWTP effluents and the removal rates for many of them were poor. Mass balance calculations showed that the three studied WWTPs in Stockholm release considerable amounts of the selected APIs into the Baltic Sea while the portions ending up in WWTP sludge were significantly lower. The levels of APIs found in drinking water are low at present, but may increase in the future unless the releases from WWTPs in the catchment of Lake MÃ¤laren are mitigated.
Ecofriendly decolorisation of Cr-complex dye Acid Black 172 by a newly isolated Pseudomonas sp. strain DY1
Authors: Du Lin-Na , Wang Sheng , Li Gang , Yang Yu-Yi , Jia Xiao-Ming , Zhao Yu-Hua
Published: February 2016

Pseudomonas sp. strain DY1 was newly isolated from soil with rotten wood and identified as a member of the genus Pseudomonas based on 16S rDNA and biochemical tests. Acid Black 172, a water soluble Cr-complex dye, was then selected as a model dye to investigate the decolorisation ability of the strain. It was observed that the growth of the strain was not inhibited by high dose of metal ions (10 mM), and efficient decolorisation was still observed when high concentrations of Fe2+, Fe3+ and Ca2+ existed. The optimal decolorising conditions obtained from Taguchi design were as follows: temperature 37˚C, pH 7.0, Fe3+ and proline concentrations of 7 mM and 3.0 g/L, respectively. Under the optimal conditions, 94.5% of Acid Black 172 (100 mg/L) could be decolorised by the strain in 24 h. The kinetics of the decolorisation best fitted the first order kinetic model (R2=0.981). Besides, the phytotoxicity study demonstrated a good detoxification by the strain. This work has a certain practical value in microbial decolorisation of textile wastewater.
Model-based evaluation of mechanisms and benefits of mainstream shortcut nitrogen removal processes
Authors: Al-Omari Ahmed , Wett Bernhard , Nopens Ingmar , De Clippeleir Haydee , Han Mofei , Regmi Pusker , Bott Charles , Murthy Sudhir
Published: February 2016

The main challenge in implementing shortcut nitrogen removal processes for mainstream wastewater treatment is the out-selection of nitrite oxidizing bacteria (NOB) to limit nitrate production. A model-based approach was utilized to simulate the impact of individual features of process control strategies to achieve NO−2-N shunt via NOB out-selection. Simulations were conducted using a two-step nitrogen removal model from the literature. Nitrogen shortcut removal processes from two case studies were modeled to illustrate the contribution of NOB out-selection mechanisms. The paper highlights a comparison between two control schemes; one was based on online measured ammonia and the other was based on a target ratio of 1 for ammonia vs. NOx (nitrate + nitrite) (AVN). Results indicated that the AVN controller possesses unique features to nitrify only that amount of nitrogen that can be denitrified, which promotes better management of incoming organics and bicarbonate for a more efficient NOB out-selection. Finally, the model was used in a scenario analysis, simulating hypothetical optimized performance of the pilot process. An estimated potential saving of 60% in carbon addition for nitrogen removal by implementing full-scale mainstream deammonification was predicted.
Microbial fuel cell-based biosensors for environmental monitoring: a review
Authors: Sun Jian-Zhong , Peter Kingori Gakai , Si Rong-Wei , Zhai Dan-Dan , Liao Zhi-Hong , Sun De-Zhen , Zheng Tao , Yong Yang-Chun
Published: February 2016

The microbial fuel cell (MFC) is an innovative technology that was initially designed to harness energy from organic waste using microorganisms. It is striking how many promising applications beyond energy production have been explored in recent decades. In particular, MFC-based biosensors are considered to be the next generation biosensing technology for environmental monitoring. This review describes recent advances in this emerging technology of MFC-based biosensors, with a special emphasis on monitoring of biochemical oxygen demand and toxicity in the environment. The progress confirms that MFC-based biosensors could be used as self-powered portable biosensing devices with great potential in long-term and remote environmental monitoring.
Inhibitory mechanisms of Acacia mearnsii extracts on the growth of Microcystis aeruginosa
Authors: Liu Zhibin , Zhou Lirong , Liu Dandan , Zhu Qiyu , Chen Wenqing
Published: February 2016

Our previous work revealed that Acacia mearnsii extract can inhibit the growth of Microcystis aeruginosa, the common species forming toxic cyanobacterial blooms in eutrophic freshwater. In the present study, we demonstrated that this plant extract can significantly increase cell membrane permeability and Ca2+/Mg2+-ATPase activity on the membrane. Long-term exposure to concentrations of 20 ppm A. mearnsii extract led to algal cell membrane leakage or even lysis. Comparison of expression of three photosynthesis-related genes (rbcL, psaB and psbD) in M. aeruginosa with and without plant extract treatment revealed that their expression was remarkably reduced in the presence of the extract. Down-regulation of photosynthesis-related genes could indicate the inhibition of the photosynthetic process. Thus, our results suggested that both photosynthetic systems and membranes of M. aeruginosa are potentially damaged by A. mearnsii extract.
Water use efficiency and productivity of habanero pepper (Capsicum chinense Jacq.) based on two transplanting dates
Authors: López-López Rutilo , Inzunza-Ibarra Marco Antonio , Sánchez-Cohen Ignacio , Fierro-Álvarez Andrés , Sifuentes-Ibarra Ernesto
Published: February 2016

Habanero pepper production was assessed with drip irrigation and plastic mulch, based on two transplanting dates. The objectives of the study were: (i) to evaluate the effect of two transplanting dates and the use of plastic mulch on water productivity and habanero pepper fruit yield under drip irrigation conditions; and (ii) to determine the profitability and economic viability of the product in the regional market. The work was conducted in the municipality of Huimanguillo, state of Tabasco, Mexico, in loam soils classified as Eutric Fluvisol. The Jaguar variety of habanero pepper, developed by INIFAP and possessing better genetic and productive characteristics, was used. Two transplanting dates were studied, (i) 30 January 2013 and (ii) 15 February 2013, with and without plastic mulch. The conclusions were: (i) application of irrigation depths based on crop evapotranspiration (ETc) and plastic mulch transplanted on 30 January increased the fruit yield of the crop and improved the benefit–cost ratio of the production system; and (ii) water use efficiency based on the 30 January transplanting date was 8.68 kg m−3 of water applied with plastic mulch, 6.51 kg m−3 without plastic mulch, and 3.65 kg m−3 for the 15 February transplanting date with plastic mulch.
Struvite precipitation in raw and co-digested swine slurries for nutrients recovery in batch reactors
Authors: Taddeo Raffaele , Lepistö Raghida
Published: February 2016

The release of nitrogen (N) and phosphorus (P) from agro-industrial sources is a major environmental concern. Furthermore, the scarcity of mineable P and the growing demand for food worldwide necessitate that we find an alternative P source. This study applied struvite precipitation for N-P recovery to slurries with high levels of organics and ammonia to achieve environmental protection from excessive nutrients diffusion and to generate a sustainable P source. Batch tests were carried out on raw and co-digested swine slurries to study the feasibility of struvite precipitation and the effect of several parameters, including pH, reaction time, competing ions (Ca2+, K+), total solids (TS), and alkalinity. The batch assays with raw swine slurries showed high N-P removals (up to 80%), while the anaerobic liquor returned lower recovery efficiency due to the high solids and alkali content. Struvite crystallization was detected at pH values as low as 6, and the characteristics of the recovered struvite matched those of the theoretical. Slight co-precipitation of calcium–phosphates occurred and was dependent on the Ca2+/Mg2+ ratio rather than on varying pH values. Struvite precipitation was shown to be feasible in complex matrices as agro-industrial effluents, characterized by high NH4+, alkalinity, solids and organic content, and interfering ions such as Ca2+ and K+.
Characteristics of nitrogen and phosphorus removal by a surface-flow constructed wetland for polluted river water treatment
Authors: Dzakpasu Mawuli , Wang Xiaochang , Zheng Yucong , Ge Yuan , Xiong Jiaqing , Zhao Yaqian
Published: February 2016

The characteristics of nitrogen (N) and phosphorus (P) removal were studied during the 2-year operation of a free water surface flow wetland of 900 m2 with hydraulic loading of 0.1 m/d to evaluate its potential to treat water from an urban stream polluted with municipal and industrial wastewater. Attention was focused on the removal of dissolved N and P by harvesting plants (local Phragmites australis and Typha orientalis) at the end of each growing season. According to findings, the removals of N and P increased from 47.1% and 17.6%, respectively, in the 1st year to 52.3% and 32.4%, respectively, in the 2nd year. Increments of N and P removal were largely attributable to plant biomass, which increased from an average dry weight of 1.77 kg/m2 in the 1st year to 3.41 kg/m2 in the 2nd year. The amount of nutrients assimilated by plants in the 2nd year was almost double that of the 1st year. Increasing biomass in the 2nd year also improved redox conditions in the substrate layer, which contributed to increasing the efficiency of N removal. Compared with T. orientalis, P. australis was more competitive and adapted to conditions in the wetland better; it regenerated more vigorously and contributed more to nutrient removal.
Submerged macrophyte Ceratophyllum demersum affects phosphorus exchange at the sediment–water interface
Authors: Dai Yanran , Cheng Shuiping , Liang Wei , Wu Zhenbin
Published: February 2016

Substantial research efforts were made to assess the effects of submerged macrophytes on water quality improvement, but information on the mechanism of submerged macrophytes relative to the exchange of phosphorus (P) at the sediment–water interface is very limited. To help fill the void, a popular species, Ceratophyllum demersum L. was chosen to address the effects and mechanisms of submerged macrophyte growth on the processes of P exchange across the sediment­–water interface. In treatment mesocosms (planted), equilibrium phosphorus concentration (EPC0) value falls from 68.4 to 36.0 µg/L, with a mean value of 52.5 µg/L. Conversely, the distribution coefficient (Kd) value has a predominantly increasing trend. But they are both significantly higher than an unplanted control (p < 0.05). Also, in the planted mesocosm, maximum phosphate sorption capacity (Qmax) was significantly reduced (4,721–3,845 mg/kg), and most of the linear correlations between different forms of phosphorus and sediment P adsorption parameters were affected (p < 0.05). The EPC0 Percentage Saturation percentages (EPCsat) in planted groups were 325% higher than that in control (p < 0.05). We conclude that C. demersum could promote the release of P from sediments, and soluble reactive phosphorus concentration in overlying water is probably the driving force for P exchange at the sediment–water interface.
About the interest of a zooplankton compartment in pond systems: methodology to study the growth kinetic of Daphnia pulex on Scenedesmus sp.
Authors: Liady M. N. D. , Tangou T. T. , Fiogbe E. D. , Cauchie H.-M. , Vasel J.-L.
Published: February 2016

A reliable characterization of cladocerans’ growth kinetic on their substrates is crucial for the estimation of their biochemical conversion rate in pond models. Although many studies reported cladocerans’ growth inhibitions by high chlorophyceae contents, their growth kinetics had continued to be described in many pond system models by Monod-type kinetic, which describes growth saturation by high substrate contents, but fails to explain the disappearance of cladocerans observed during chlorophyceae's bloom periods. This study aimed to develop a methodology and assess whether growth-inhibition-type models used to describe microbial growth kinetics can be applicable to cladocerans. Experiments were carried out using Daphnia pulex populations and Scenedesmus sp. First, biomass of D. pulex was measured through digital image processing (DIP) during growth experiments. Then, three candidate models (i.e., Andrews, Edward and Haldane models), along with the Monod model, were fitted to the observed data and compared. The results showed that the DIP technique provided reliable results for estimating the biomass of D.pulex. Our findings show that the candidate growth inhibition-type models satisfactorily described D. pulex's growth kinetic (86% variance accounted for). Scenesdemus sp. were not strong inhibitors of the growth of D. pulex (high inhibition constant and low half-saturation constant found).
French vertical-flow constructed wetland design: adaptations for tropical climates
Authors: Molle P. , Lombard Latune R. , Riegel C. , Lacombe G. , Esser D. , Mangeot L.
Published: February 2016

The French Outermost Regions are under tropical climate yet still have to comply with both French and EU regulations. French vertical-flow constructed wetland systems appear well adapted to the technical specifics of these regions but their adaptation to tropical climate requires new design guidelines to be defined (area needed, number of filters, type of plants, material to be used, etc.). A study was started in 2008, with backing from the national water authorities, to implement full-scale experimental sites and assess the impacts of local context on design and performances. This paper reports the monitoring results on three vertical-flow constructed wetlands fed directly with raw wastewater (known as the ‘French system’) in Mayotte and French Guiana. The plants, now in operation for between 1 and 6 years, range from 160 to 480 population equivalent (p.e.). Monitoring consisted of 28 daily composite flow samples in different seasons (dry season, rainy season) at the inlet and outlet of each filter. Performances are benchmarked against French mainland area standards from Irstea's database. Results show that performances are improved by warmer temperature for chemical oxygen demand (COD), suspended solids (SS) and total Kjeldahl nitrogen (TKN) and satisfy national quality objectives with a single stage of filters. Treatment plant footprint can thus be reduced as only two parallel filters are needed. Indeed, warm temperatures allow faster mineralization of the sludge deposit, making it possible to operate at similar rest and feeding period durations. Systems operated using one twin-filter stage can achieve over 90% COD, SS and TKN removal for a total surface of 0.8 m²/p.e.
Preparation of cationic starch microspheres and study on their absorption to anionic-type substance
Authors: Zheng Jie , Wang YaNan , Feng ZuoShan , Kuang ZeMin , Zhao DeZhou , Jiao XueMin
Published: February 2016

Cationic starch microspheres (CSMs) were prepared from lab-made neutral starch-based microspheres using a cationic adsorbent, namely 3-chloro-2-hydroxypropyltrimethyl ammonium chloride, as the cationic etherifying agent. Detection by scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), and laser diffraction techniques revealed that CSMs had coarse surfaces with good sphericity and dispersibility. Differential thermal analysis showed the lower thermostability of the CSMs’ main chains. Furthermore, scores of experiments confirmed that CSMs are capable of absorption to N-(phosphonomethyl) iminodiacetic acid (PMIDA), a type of anionic substance, which is the intermediate to the preparation of glyphosate, maximally up to 95.24 mg/g. Compared with the Freundlich isotherm model, the Langmuir isotherm model can better describe the absorption process. The kinetic study showed that the pseudo-second-order model demonstrated a better correlation of the experimental data in contrast with the pseudo-first-order model. It can be therefore concluded that the rate-limiting step was the chemical absorption rather than the mass transport.
Removal of dyes from aqueous solutions using activated carbon prepared from rice husk residue
Authors: Li Yaxin , Zhang Xian , Yang Ruiguang , Li Guiying , Hu Changwei
Published: February 2016

The treatment of dye wastewater by activated carbon (AC) prepared from rice husk residue wastes was studied. Batch adsorption studies were conducted to investigate the effects of contact time, initial concentration (50–450 mg/L), pH (3–11) and temperature (30–70 °C) on the removal of methylene blue (MB), neutral red, and methyl orange. Kinetic investigation revealed that the adsorption of dyes followed pseudo-second-order kinetics. The results suggested that AC was effective to remove dyes, especially MB, from aqueous solutions. Desorption studies found that chemisorption by the adsorbent might be the major mode of dye removal. Fourier transform infrared results suggested that dye molecules were likely to combine with the O–H and P=OOH groups of AC.
Start-up of two moving bed membrane bioreactors treating saline wastewater contaminated by hydrocarbons
Authors: Campo R. , Di Prima N. , Freni G. , Giustra M. G. , Di Bella G.
Published: February 2016

This work aims to assess the acclimation of microorganisms to a gradual increase of salinity and hydrocarbons, during the start-up of two moving bed membrane bioreactors (MB-MBRs) fed with saline oily wastewater. In both systems an ultrafiltration membrane was used and two types of carriers were employed: polyurethane sponge cubes (MB-MBRI) and polyethylene cylindrical carriers (MB-MBRII). A decreasing dilution factor of slops has been adopted in order to allow biomass acclimation. The simultaneous effect of salinity and hydrocarbons played an inhibitory role in biomass growth and this resulted in a decrease of the biological removal efficiencies. A reduction of bound extracellular polymeric substances and a simultaneous release of soluble microbial products (SMPs) were observed, particularly in the MB-MBRII system, probably due to the occurrence of a greater suspended biomass stress as response to the recalcitrance of substrate. On the one hand, a clear attachment of biomass occurred only in MB-MBRI and this affected the fouling deposition on the membrane surface. The processes of detachment and entrapment of biomass, from and into the carriers, significantly influenced the superficial cake deposition and its reversibility. On the other hand, in MB-MBRII, the higher production of SMPs implied a predominance of the pore blocking.
Valuation of OSA process and folic acid addition as excess sludge minimization alternatives applied in the activated sludge process
Authors: Martins C. L. , Velho V. F. , Ramos S. R. A. , Pires A. S. C. D. , Duarte E. C. N. F. A. , Costa R. H. R.
Published: February 2016

The aim of this study was to investigate the ability of the oxic-settling-anaerobic (OSA)-process and the folic acid addition applied in the activated sludge process to reduce the excess sludge production. The study was monitored during two distinct periods: activated sludge system with OSA-process, and activated sludge system with folic acid addition. The observed sludge yields (Yobs) were 0.30 and 0.08 kgTSS kg–1 chemical oxygen demand (COD), control phase and OSA-process (period 1); 0.33 and 0.18 kgTSS kg–1 COD, control phase and folic acid addition (period 2). The Yobs decreased by 73 and 45% in phases with the OSA-process and folic acid addition, respectively, compared with the control phases. The sludge minimization alternatives result in a decrease in excess sludge production, without negatively affecting the performance of the effluent treatment.
Potential of nitrous oxide recovery from an aerobic/oxic/anoxic SBR process
Authors: Zhao Jianqiang , Huang Nan , Hu Bo , Jia Luwei , Ge Guanghuan
Published: February 2016

A single sequencing batch reactor (SBR) with an operating mode of anaerobic/oxic/anoxic (A/O/A) was developed to determine a simpler process to recover nitrous oxide (N2O) from synthetic wastewater containing ammonia and glucose. This SBR system was initiated in A/O mode to implement nitritation (ammonia to nitrite) and then switched to A/O/A mode. Using measurements of the dissolved N2O concentration and release rate, the total production and conversion rate of N2O were calculated to reveal the potential of producing and recovering N2O in the extended anoxic phase. Results showed that the A/O/A SBR could convert the majority of the nitrite available in the system into N2O by heterotrophic denitritation over longer anoxic periods, and a conversion rate of 77% could be achieved. As a consequence, the A/O/A SBR presents potential ability to produce and recover N2O from wastewater containing ammonia and organic carbon.
Levels of six antibiotics used in China estimated by means of wastewater-based epidemiology
Authors: Yuan Su-Fen , Liu Ze-Hua , Huang Ri-Ping , Yin Hua , Dang Zhi
Published: February 2016

Due to lack of proper regulation, information about antibiotics consumption in many countries such as China is difficult to obtain. In this study, a simple method based on wastewater-based epidemiology was adopted to estimate their usage in four megacities of China. Six antibiotics (norfloxacin, ofloxacin, sulfamethoxazole, trimethoprim, erythromycin and roxithromycin), which are the most frequently consumed antibiotics in China, were selected as the targets. Based on our results, Chongqing had the largest total annual consumption of the selected six antibiotics among the four megacities, followed by Guangzhou, then Hong Kong, with Beijing having the least, with values of 4.4 g/y/P, 4.0 g/y/P, 1.6 g/y/P, and 1.3 g/y/P, respectively. Compared with the daily consumption per capita in Italy, the estimated consumption levels of the selected six antibiotics in four cities of China were 12–41 times those of Italy. Our results suggested that the consumption of antibiotics in China was excessive.
Study of novel mechano-chemical activation process of red mud to optimize nitrate removal from water
Authors: Alighardashi A. , Gharibi H. R. , Raygan Sh. , Akbarzadeh A.
Published: February 2016

Red mud (RM) is the industrial waste of alumina production and causes serious environmental risks. In this paper, a novel activation procedure for RM (mechano-chemical processing) is proposed in order to improve the nitrate adsorption from water. High-energy milling and acidification were selected as mechanical and chemical activation methods, respectively. Synthesized samples of adsorbent were produced considering two parameters of activation: acid concentrations and acidification time in two selected milling times. Optimization of the activation process was based on nitrate removal from a stock solution. Experimental data were analyzed with two-way analysis of variance and Kruskal–Wallis methods to verify and discover the accuracy and probable errors. Best conditions (acceptable removal percentage > 75) were 17.6% w/w for acid concentrate and 19.9 minutes for acidification time in 8 hours for milling time. A direct relationship between increase in nitrate removal and increasing the acid concentration and acidification time was observed. The adsorption isotherms were studied and compared with other nitrate adsorbents. Characterization tests (X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectrophotometry, dynamic light scattering, surface area analysis and scanning electron microscopy) were conducted for both raw and activated adsorbents. Results showed noticeable superiority in characteristics after activation: higher specific area and porosity, lower particle size and lower agglomeration in structure.
Research on the stability of heavy metals (Cu, Zn) in excess sludge with the pretreatment of thermal hydrolysis
Authors: Wu Huimin , Li Meng , Zhang Lei , Sheng Chao
Published: February 2016

Thermal hydrolysis (TH) has been used to improve anaerobic digestion performance as well as the stability of heavy metals in sludge. Because the toxicity of heavy metals is closely related to both the concentration and the chemical speciation, more exhaustive studies on speciation distribution are urgently needed. This research aimed to investigate the effects of TH treatment (especially the time and temperature) on the concentration and stability of heavy metals in sludge, and to define the optimal TH conditions. The TH experiment indicated that the content of the stable form of Cu and Zn reached 83% and 47.4%, respectively, with TH at 210°C and 30 min. Compared with the raw sludge, the proportion of Cu and Zn increased by 11.88% and 7.3%, respectively. Results indicated that the heavy metals were combined with sludge in a more stable form with the pretreatment of TH, which improved the stability of heavy metals.
A controlled wet-spinning and dip-coating process for preparation of high-permeable TiO2 hollow fiber membranes
Authors: Zhang Qi , Wang Hua , Fan Xinfei , Chen Shuo , Yu Hongtao , Quan Xie
Published: February 2016

In order to improve the permeate flux of photocatalytic membranes, we present an approach for coupling TiO2 with ceramic hollow fiber membranes. The ceramic hollow fiber membranes with high permeate flux were fabricated by a controlled wet-spinning process using polyethersulfone (PESf) and ceramic powder as precursors and 1-methyl-2-pyrrolidinone as solvent, and the subsequent TiO2 coating was performed by a dip-coating process using tetra-n-butyl titanate as precursor. It has been found that the PESf/ceramic powder ratio could influence the structure of the membranes. Here the as-prepared TiO2 hollow fiber membranes had a pure water flux of 4,450 L/(m2·h). The performance of the TiO2 hollow fiber membrane was evaluated using humic acid (HA) as a test substance. The results demonstrated that this membrane exhibited a higher permeate flux under UV irradiation than in the dark and the HA removal efficiency was enhanced. The approach described here provides an operable route to the development of high-permeable photocatalytic membranes for water treatment.
Mineralization of sulfamethizole in photo-Fenton and photo-Fenton-like systems
Authors: Wu C. H. , Wu J. T. , Lin Y. H.
Published: February 2016

In this investigation, UV/H2O2, UV/H2O2/Fe2+ (photo-Fenton) and UV/H2O2/Fe3+ (photo-Fenton-like) systems were used to mineralize sulfamethizole (SFZ). The optimal doses of H2O2 (1–20 mM) in UV/H2O2 and iron (0.1–1 mM) in photo-Fenton and photo-Fenton-like systems were determined. Direct photolysis by UV irradiation and direct oxidation by added H2O2, Fe2+ and Fe3+ did not mineralize SFZ. The optimal dose of H2O2 was 10 mM in UV/H2O2 and that of iron (Fe2+ or Fe3+) was 0.2 mM in both UV/H2O2/Fe2+ and UV/H2O2/Fe3+ systems. Under the best experimental conditions and after 60 min of reaction, the SFZ mineralization percentages in UV/H2O2, UV/H2O2/Fe2+ and UV/H2O2/Fe3+ systems were 16, 90 and 88%, respectively. The UV/H2O2/Fe2+ and UV/H2O2/Fe3+ systems effectively mineralized SFZ.
Contaminant removal in septage treatment with vertical flow constructed wetlands operated under batch flow conditions
Authors: Jong Valerie Siaw Wee , Tang Fu Ee
Published: February 2016

Individual septic tanks are the most common means of on-site sanitation in Malaysia, but they result in a significant volume of septage. A two-staged vertical flow constructed wetlands (VFCWs) system for the treatment of septage was constructed and studied in Sarawak, Malaysia. Raw septage was treated in the first stage wetlands, and the resulting percolate was fed onto the second stage wetlands for further treatment. Here, the effects of a batch loading regime on the contaminant removal efficiency at the second stage wetlands, which included palm kernel shell within their filter substrate, are presented. The batch loading regime with pond:rest (P:R) period of 1:1, 2:2 and 3:3 (day:day) was studied. The improvement of the effluent redox condition was evident with P:R = 3:3, resulting in excellent organic matters (chemical oxygen demand and biochemical oxygen demand) and nitrogen reduction. The bed operated with P:R = 1:1 experienced constant clogging, with a water layer observed on the bed surface. For the P:R = 3:3 regime, the dissolved oxygen profile was not found to decay drastically after 24 hours of ponding, suggesting that the biodegradation mainly occurred during the first day. The study results indicate that a suitable application regime with an adequate rest period is important in VFCWs to ensure efficient operation.
Evaluating new processes and concepts for energy and resource recovery from municipal wastewater with life cycle assessment
Authors: Remy C. , Boulestreau M. , Warneke J. , Jossa P. , Kabbe C. , Lesjean B.
Published: February 2016

Energy and resource recovery from municipal wastewater is a pre-requisite for an efficient and sustainable water management in cities of the future. However, a sound evaluation of available processes and pathways is required to identify opportunities and short-comings of the different options and reveal synergies and potentials for optimization. For evaluating environmental impacts in a holistic view, the tool of life cycle assessment (LCA, ISO 14040/44) is suitable to characterize and quantify the direct and indirect effects of new processes and concepts. This paper gives an overview of four new processes and concepts for upgrading existing wastewater treatment plants towards energy positive and resource efficient wastewater treatment, based upon an evaluation of their environmental impacts with LCA using data from pilot and full-scale assessments of the considered processes.
Effect of cathode electron acceptors on simultaneous anaerobic sulfide and nitrate removal in microbial fuel cell
Authors: Cai Jing , Zheng Ping , Mahmood Qaisar
Published: February 2016

The current investigation reports the effect of cathode electron acceptors on simultaneous sulfide and nitrate removal in two-chamber microbial fuel cells (MFCs). Potassium permanganate and potassium ferricyanide were common cathode electron acceptors and evaluated for substrate removal and electricity generation. The abiotic MFCs produced electricity through spontaneous electrochemical oxidation of sulfide. In comparison with abiotic MFC, the biotic MFC showed better ability for simultaneous nitrate and sulfide removal along with electricity generation. Keeping external resistance of 1,000 Ω, both MFCs showed good capacities for substrate removal where nitrogen and sulfate were the main end products. The steady voltage with potassium permanganate electrodes was nearly twice that of with potassium ferricyanide. Cyclic voltammetry curves confirmed that the potassium permanganate had higher catalytic activity than potassium ferricyanide. The potassium permanganate may be a suitable choice as cathode electron acceptor for enhanced electricity generation during simultaneous treatment of sulfide and nitrate in MFCs.
Optimization of the synthesis process of an iron oxide nanocatalyst supported on activated carbon for the inactivation of Ascaris eggs in water using the heterogeneous Fenton-like reaction
Authors: Morales-Pérez Ariadna A. , Maravilla Pablo , Solís-López Myriam , Schouwenaars Rafael , Durán-Moreno Alfonso , Ramírez-Zamora Rosa-María
Published: February 2016

An experimental design methodology was used to optimize the synthesis of an iron-supported nanocatalyst as well as the inactivation process of Ascaris eggs (Ae) using this material. A factor screening design was used for identifying the significant experimental factors for nanocatalyst support (supported %Fe, (w/w), temperature and time of calcination) and for the inactivation process called the heterogeneous Fenton-like reaction (H2O2 dose, mass ratio Fe/H2O2, pH and reaction time). The optimization of the significant factors was carried out using a face-centered central composite design. The optimal operating conditions for both processes were estimated with a statistical model and implemented experimentally with five replicates. The predicted value of the Ae inactivation rate was close to the laboratory results. At the optimal operating conditions of the nanocatalyst production and Ae inactivation process, the Ascaris ova showed genomic damage to the point that no cell reparation was possible showing that this advanced oxidation process was highly efficient for inactivating this pathogen.
Comprehensive scenario management of sustainable spatial planning and urban water services
Authors: Baron Silja , Hoek Jannis , Kaufmann Alves Inka , Herz Sabine
Published: February 2016

Adaptations of existing central water supply and wastewater disposal systems to demographic, climatic and socioeconomic changes require a profound knowledge about changing influencing factors. The paper presents a scenario management approach for the identification of future developments of drivers influencing water infrastructures. This method is designed within a research project with the objective of developing an innovative software-based optimisation and decision support system for long-term transformations of existing infrastructures of water supply, wastewater and energy in rural areas. Drivers of water infrastructures comprise engineering and spatial factors and these are predicted by different methods and techniques. The calculated developments of the drivers are illustrated for a model municipality. The developed scenario-manager enables the generation of comprehensive scenarios by combining different drivers. The scenarios are integrated into the optimisation model as input parameters. Furthermore, the result of the optimisation process – an optimal transformation strategy for water infrastructures – can have impacts on the existing fee system. General adaptation possibilities of the present fee system are presented.
Adsorption of Pb2+ from aqueous solution using spinel ferrite prepared from steel pickling sludge
Authors: Fang Binbin , Yan Yubo , Yang Yang , Wang Fenglian , Chu Zhen , Sun Xiuyun , Li Jiansheng , Wang Lianjun
Published: February 2016

In this paper, spinel ferrite with high crystallinity and high saturation magnetization was successfully prepared from steel pickling sludge by adding iron source and precipitator in the hydrothermal condition. The obtained spinel ferrite was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), vibrating sample magnetometer (VSM), and Zeta potential methods and investigated as an adsorbent for removal of Pb2+ from aqueous solution. Batch experiments were performed by varying the pH values, contact time, temperature and initial metal concentration. The result of pH impact showed that the adsorption of Pb2+ was a pH dependent process, and the pH 5.8 ± 0.2 was found to be the optimum condition. The achieved experimental data were analyzed with various kinetic and isotherm models. The kinetic studies revealed that Pb2+ adsorption onto spinel ferrite followed a pseudo-second order model, and the Langmuir isotherm model provided the perfect fit to the equilibrium experimental data. At different temperatures, the maximum Pb2+ adsorption capacities calculated from the Langmuir equation were in the range of 126.5–175.4 mg/g, which can be in competition with other adsorbents. The thermodynamic results showed that the spinel ferrite could spontaneously and endothermically adsorb Pb2+ from aqueous solution. The regeneration studies showed that spinel ferrite could be used five times (removal efficiency (%) >90%) by desorption with HNO3 reagent.
Removal of sodium and chloride ions from aqueous solutions using fique fibers (Furcraea spp.)
Authors: Agudelo Nikolay , Hinestroza Juan P. , Husserl Johana
Published: February 2016

Fique fibers obtained from the leaves of Furcraea spp., a highly abundant plant in the mountains of South America, may offer an alternative as biosorbents in desalination processes as they exhibit high removal capacities (13.26 meq/g for chloride ions and 15.52 meq/g for sodium ions) up to four times higher than exchange capacities commonly observed in synthetic resins. The ion removal capacity of the fibers was also found to be a function of the pH of the solution with the maximum removal of ions obtained at pH 8. Unlike most commercial ion exchange resins, our results suggest that fique fibers allow simultaneous removal of chloride and sodium ions.
Kinetic studies of nitrate removal from aqueous solution using granular chitosan-Fe(III) complex
Authors: Hu Qili , Chen Nan , Feng Chuanping , Zhang Jing , Hu Weiwu , Lv Long
Published: February 2016

In the present study, a granular chitosan-Fe(III) complex was prepared as a feasible adsorbent for the removal of nitrate from an aqueous solution. There was no significant change in terms of nitrate removal efficiency over a wide pH range of 3–11. Nitrate adsorption on the chitosan-Fe(III) complex followed the Langmuir–Freundlich isotherm model. In order to more accurately reflect adsorption and desorption behaviors at the solid/solution interface, kinetic model I and kinetic model II were proposed to simulate the interfacial process in a batch system. Nitrate adsorption on the chitosan-Fe(III) complex followed the pseudo-first-order kinetic model and kinetic model I. The proposed half-time could provide useful information for optimizing process design. Adsorption and desorption rate constants obtained from kinetic model I and kinetic model II were beneficial to understanding the interfacial process and the extent of adsorption reaction. Kinetic model I and kinetic model II implied that nitrate uptake exponentially approaches a limiting value.
HIL evaluation of control unit in grid-tied coverters
Authors: Porobic Vlado , Adzic Evgenije , Rapaic Milan
Published: February 2016

Hardware-in-the-Loop (HIL) emulation is poised to become unsurpassed design
tool for development, testing, and optimization of real-time control
algorithms for grid connected power electronics converters for distributed
generation, active filters and smart grid applications. It is strongly
important to examine and test how grid connected converters perform under
different operating conditions including grid disturbances and faults. In
that sense, converter?s controller is a key component responsible for
ensuring safe and high-performance operation. This paper demonstrates an
example how ultra-low latency and high fidelity HIL emulator is used to
easily, rapidly and exhaustively test and validate standard control strategy
for grid connected power electronics converters, without need for expensive
hardware prototyping and laboratory test equipment.
Energy efficiency cart modeling of solar energy collectors by genetic programming
Authors: Kovac Pavel , Petrovic Vladan , Pucovsky Vladimir , Bircanin Bojan , Savkovic Borislav , Gostimirovic Marin
Published: February 2016

Uniquely constructed technical solution of solar energy collector is
presented in this paper. It presents a great breakthrough in the field of
energy efficiency and successful exploitation of renewable energy sources.
Principle of this high-temperature energy storage enables the energy
accumulated from the sun to be yielded when necessary and continuously, 24
hours a day and 365 days a year. Furthermore this paper is containing a
modeling of sun irradiance, generated energy intensity for flat solar panel
and for Prof. Petrovic concentrator. Modeling is made with genetic
programming and it is found out that genetic programming is suitable method
for modeling of energy intensity. It offers results which are within
acceptable tolerances while maintaining ease of use and short computational
time. Genetic programming yielded results of 12,97%, 14,6% and 9,25% average
percent error for irradiance, flat solar panel and Prof. Petrovic solar
concentrator respectively.
Hybrid motion control of humanoid robot for leader-follower cooperative tasks
Authors: Savic Srdjan , Rakovic Mirko , Borovac Branislav , Nikolic Milutin
Published: February 2016

This paper presents a framework for leader-follower type cooperative
transportation of an object by multiple humanoid robots or a single robot and
a human. The emphasis in this paper is on the hybrid control algorithm and
motion generation of the follower robot, while the influence of the leader
has been simulated as external force acting on the follower?s hands. The
presented approach uses impedance controller to provide compliant behavior of
robot arms and it is an extension of our previous work on dual-mode impedance
controller for safe human-robot interaction. Synthesis of the follower?s legs
and trunk motion is based on the reconfigurable adaptive motion primitives,
which are defined as simple, parameterized motion building blocks that can be
combined in a sequence or in parallel to generate complex motion. It has been
already proven that motion generation, based on reconfigurable adaptive
primitives enables the robot to modify gait parameters online, at any time
instant, and to synthesize dynamically balanced walk. Motion of the follower
is based on the reactive approach, where the gait parameters (walking
velocity, direction and step length) depend on the intensity and the
direction of the external force vector. Robot end-effectors are compliant in
the horizontal plain, adapting to the physical guidance of the leader, while
being stiff in the vertical direction in order to compensate the external
force in negative Z direction. The proposed framework has been tested by
numerical simulations involving a dynamic robot model.
Speed-sensorless control strategy for multi-phase induction generator in wind energy conversion systems
Authors: Dumnic Boris , Milicevic Dragan , Popadic Bane , Katic Vladimir , Corba Zoltan
Published: February 2016

Renewable energy sources, especially wind energy conversion systems (WECS),
exhibit constant growth. Increase in power and installed capacity led to
advances in WECS topologies. Multi-phase approach presents a new development
direction, with several key advantages over three-phase systems. Paired with
a sensorless control strategy, multi-phase machines are expected to take
primacy over standard solutions. This paper presents speed sensorless vector
control of an asymmetrical six-phase induction generator based on a model
reference adaptive system (MRAS). Suggested topology and developed control
algorithm show that sensorless control can yield appropriate dynamic
characteristics for the use in WECS with increase in reliability and
robustness.
The Interplay of Client Management and the Audit Committee on Auditor Performance
Authors: Brown J. Owen , Popova Velina K.
Published: February 2016

This article summarizes “The Interplay of Management Incentives and Audit Committee Communication on Auditor Judgment” (Brown and Popova 2016), which investigates the influence that client management and the audit committee have on auditor judgments and behavior. We find that additional, informal audit committee communication with the auditor, as directed under the recently issued Auditing Standard No. 16, Communications with Audit Committees, has a significant and positive impact on auditors' evidence evaluation and related judgments under certain conditions. Specifically, when client management has greater incentives to try to unduly influence the auditor, this additional communication has a significant, positive impact on auditors' evidence evaluation and related judgments. However, when client management is perceived as having lower incentives, management becomes more persuasive than the audit committee and is able to influence the auditors into accepting an aggressive, management-preferred accounting outcome. We discuss the implications of our findings for auditors, companies, and regulators who are interested in the role of corporate governance and, more specifically, the interrelationships required among management, the auditor, and the audit committee for enhancing financial reporting quality.
Interaction between deglutition, tongue posture, and malocclusion: A comparison of intraoral compartment formation in subjects with neutral occlusion or different types of malocclusion
Authors: Knösel Michael , Nüser Carolin , Jung Klaus , Helms Hans-Joachim , Engelke Wilfried , Sandoval Paulo
Published: February 2016

Objective: 

To test the null hypothesis of no significant difference in terms of intraoral pressure curve characteristics assessed simultaneously at the subpalatal space (SPS) and the vestibular space (VS), during different oral postures, between four groups with either an Angle Class II/1 (II1), Angle Class II/2 (II2), anterior open bite (O) malocclusion, or a neutral occlusion control group (I).

Materials and Methods: 

Intraoral pressure recordings were performed simultaneously in the VS and SPS of 69 consecutive subjects (nII1  =  15; nII2  =  17; nO  =  17; nI  =  20; mean age/standard deviation 18.43/6.60 years). Assessments included defined sections of open mouth posture (OMP, 30 seconds), anteriorly closed mouth condition (60 seconds), dynamics by a tongue-repositioning maneuver (TRM, 60 seconds), swallowing, and positive pressure generation (PP, 10 seconds). Interactions of malocclusion, compartment location, and posture on pressure curve characteristics were analyzed by Kruskal-Wallis and Mann-Whitney U-tests, adopting an α level of 5%.

Results: 

Globally significant group differences were detected at the VS (plateau duration and median peak heights during TRM; area under pressure curve [AUC] during PP) and SPS (AUC during TRM and PP). Subjects with anteriorly nonopen dental configurations (groups I and II2) were able to keep negative pressure levels at the VS for longer time periods during TRM, compared to groups O and II1.

Conclusions: 

The null hypothesis was rejected for mean VS plateau durations and peak heights and for SPS AUC. Negative pressures at the VS may stabilize outer soft tissues passively and may explain the dental arch form shaping effect by mimic muscles.