bluuebunny/crossref_metadata_2025 huggingface dataset:
Automated equipment for anaerobic sludge parameters determination
Authors: Fdz-Polanco F. , Nieto P. , Pérez Elvira S. , van der Zee F.P. , Fdz-Polanc M. , García P.A.
Published: May 2018

Methanogenic activity, anaerobic biodegradability and toxicity are key parameters in the design and operation of anaerobic bioreactors. A large variety of methods exist for the determination of these parameters but a normalized method has not been established so far. This paper presents the development of an automated manometric system for the determination of these anaerobic sludge parameters. The system is based on monitoring the production of methane by using a pressure transducer that measures the pressure in a gas-collecting chamber of known adjustable volume, which is independent of the space where biogas production takes place. The evolution of pressure generated by the accumulation of methane relates to the conversion of COD. In this way, the methanogenic activity of the sludge can be determined, as well as the biodegradability of solids and liquid, as well as the methanogenic toxicity of compounds. The equipment permits gas sampling, as well as extraction and introduction of liquid, without losing the anaerobic conditions. Various assays have been conducted to test the reliability and reproducibility of the obtained results, showing a high level of both. The methanogenic activities obtained in the assays ranged between 0.1 and 1.8 g COD g−1 VSS d−1, and the biodegradability of the organic compounds tested ranged between 20 and 90%.
Thermophilic anaerobic digester with ultrafilter for solids stabilization
Authors: Zitomer D.H. , Bachman T.C. , Vogel D.S.
Published: May 2018

A thermophilic anaerobic digester with ultrafilter (TADU) for solids separation offers potential advantages of higher VS destruction, biomass retention, and pathogen removal. However, potential disadvantages include ultrafilter fouling, decreasing flux, and high VFA concentrations. In this study, a thermophilic anaerobic digester coupled to a sintered titanium, cross-flow ultrafilter was operated for over five months. Dairy manure was digested (HRT of 23 days). The filtrate VFA concentration was low (220 mg/L as HAc), average VS destruction was 49%, and a low average effluent fecal coliform concentration of 102 MPN/100 mL was observed. The low coliform value may be beneficial if dewatered biosolids are used for livestock bedding since low pathogen counts help prevent mastitis. Ultrafilter fluxes of 40–80 L/m2-hr were maintained by cleaning using caustic (3.5% NaOH) followed by water and acid (3% phosphoric acid). Sand from livestock bedding was found to damage the pump and ultrafilter. If TADU were implemented at full scale, then replacing sand bedding with dewatered biosolids should be considered.
Flow pattern visualization in a mimic anaerobic digester: experimental and computational studies
Authors: Vesvikar M.S. , Varma R. , Karim K. , Al-Dahhan M.
Published: May 2018

Advanced non-invasive experiments like computer automated radioactive particle tracking and computed tomography along with computational fluid dynamics (CFD) simulations were performed in mimic anaerobic digesters to visualize their flow pattern and obtain hydrodynamic parameters. The mixing in the digester was provided by sparging gas at three different flow rates. The simulation results in terms of overall flow pattern, location of circulation cells and stagnant regions, trends of liquid velocity profiles, and volume of dead zones agree reasonably well with the experimental data. CFD simulations were also performed on different digester configurations. The effects of changing draft tube size, clearance, and shape of the tank bottoms were calculated to evaluate the effect of digester design on its flow pattern. Changing the draft tube clearance and height had no influence on the flow pattern or dead regions volume. However increasing the draft tube diameter or incorporating a conical bottom design helped in reducing the volume of the dead zones as compared to a flat bottom digester. The simulations showed that the gas flow rate sparged by a single point (0.5 cm diameter) sparger does not have appreciable effect on the flow pattern of the digesters.
Assessing the environmental burdens of anaerobic digestion in comparison to alternative options for managing the biodegradable fraction of municipal solid wastes
Authors: Haight M.
Published: May 2018

Biological treatment processes including anaerobic digestion (biogasification) and composting are increasingly being considered by waste management officials and planners as alternatives for managing the mainly organic residues of municipal solid wastes (MSW). The integrated waste management model which is based upon the application of life-cycle analysis was employed to compare the environmental burdens of landfilling, composting and anaerobic digestion of MSW at a mid-sized Canadian community. Energy consumption (or recovery), residue recoveries and emissions to air and water were quantified. Scenario comparisons were analyzed to demonstrate that the environmental burdens associated with anaerobic digestion are reduced in comparison with the alternative options. The major benefit occurs as a result of the electricity produced from burning the biogas and then supplying the ‘green power’ to the local electrical grid.
Estimation of diffuse and point source microbial pollution in the Ribble catchment discharging to bathing waters in the north west of England
Authors: Wither A. , Greaves J. , Dunhill I. , Wyer M. , Stapleton C. , Kay D. , Humphrey N. , Watkins J. , Francis C. , McDonald A. , Crowther J.
Published: May 2018

Achieving compliance with the mandatory standards of the 1976 Bathing Water Directive (76/160/EEC) is required at all UK identified bathing waters. In recent years, the Fylde coast has been an area of significant investments in ‘point source’ control, which have not proven, in isolation, to satisfactorily achieve compliance with the mandatory, let alone the guide, levels of water quality in the Directive. The potential impact of riverine sources of pollution was first confirmed after a study in 1997. The completion of sewerage system enhancements offered the potential for the study of faecal indicator delivery from upstream sources comprising both point sources and diffuse agricultural sources. A research project to define these elements commenced in 2001. Initially, a desk study reported here, estimated the principal infrastructure contributions within the Ribble catchment. A second phase of this investigation has involved acquisition of empirical water quality and hydrological data from the catchment during the 2002 bathing season. These data have been used further to calibrate the ‘budgets’ and ‘delivery’ modelling and these data are still being analysed. This paper reports the initial desk study approach to faecal indicator budget estimation using available data from the sewerage infrastructure and catchment sources of faecal indicators.
Nutrient load estimation in nonpoint source pollution of Hong Kong region
Authors: Li H.E. , Lee J.H.W. , Koenig A. , Jayawardena A.W.
Published: May 2018

Red tides and eutrophication have been frequently observed over the past two decades in coastal waters around Hong Kong, which are caused by many factors and one of them is the nutrient from nonpoint source pollution (NSP). This paper concentrates on the nutrients carried by river flow from watersheds. Since there are no systematical data sets of nonpoint source pollution in Hong Kong, monthly river water quality measurements, rainfall and river flow data, land uses, and other related information are used to analyze the characteristics of NSP and estimate the nutrient loads for Hong Kong region. Main achievements are as follows: firstly, besides mean concentration for single land use, the concept of integrated mean concentration for mixed land uses was proposed and applied. Secondly, mean concentrations were carried out for different land uses (agriculture, town, grassland, shrubland and woodland), each Water Control Zone, and Hong Kong region. Thirdly, the annual nutrient loads were estimated, for the first time in this paper, with various methods for the whole area of Hong Kong, and about 8,000 tons of TN and 1,500 tons TP are transported into coastal waters from Hong Kong's land in 1998.
Results of 10 years of monitoring nitrogen in the sandy regions in The Netherlands
Authors: Fraters D. , Boumans L.J.M. , van Leeuwen T.C. , de Hoop W.D.
Published: May 2018

The effect of policy measures on agriculture and water quality with respect to nitrogen have been monitored on farms in the sandy regions since the early 1990s. Nitrogen surplus on dairy farms decreased by 100 kg/ha (30%) in the 1991–1999 period due to demonstration projects and the implementation of MINAS, limiting farm gate balance surplus. Nitrogen surplus on arable farms has slightly decreased (30 kg/ha, i.e. 20%), probably because MINAS became mandatory for arable farms from 2001 onwards. About 25% of the farm-gate balance N surplus leached as nitrate into the upper metre of the groundwater. The NO3-N concentration decreased in the 1992–2001 period, but the decrease was larger for dairy farms (16 mg/l, 46%) than for arable farms (7.7 mg/l, 30%). Of the decrease in NO3-N concentration on dairy farms, 23% is caused by a decrease in N surplus, and 27% by environmental factors, such as a higher precipitation surplus, more wet soils and more peat soils in the second part of the monitoring period. However, unknown factors are responsible for 50% of the decrease.
Statistical modelling of riverine nutrient sources and retention in the Lake Peipsi drainage basin
Authors: Vassiljev A. , Stålnacke P.
Published: May 2018

Implementation of the Water Framework Directive calls for methodologies and tools to quantify nutrient losses from diffuse sources at a river basin district scale. Here, we examine the possibility of using a statistical model for source apportionment and retention of nutrients in a large transboundary drainage basin (44,000 km2). The model approach uses non-linear regression for simultaneous estimation of e.g. source strength, i.e. export coefficients to surface waters, for the different specified land-use or soil categories and retention coefficients for pollutants in a drainage basin. The model was tested on data from 26 water quality stations with corresponding sub-basin data, i.e., land cover, point sources and atmospheric deposition, from the Estonian part of the Lake Peipsi drainage basin. The model showed that it was statistically possible to derive reliable export coefficients (i.e. unit-area loads) for nitrogen on agricultural land and forests. Moreover, it was shown with simple empirical functions that lake retention was approximately 30-35% for both nitrogen and phosphorus and that the riverine retention was low for both nitrogen and phosphorus (approx. 10%). Results show that the MESAW model is a simple and powerful tool for simultaneous estimation of sources and retention of nutrient loads in a river basin.
Effect of pre-coagulation on mitigating irreversible fouling during ultrafiltration of a surface water
Authors: Kimura K. , Hane Y. , Watanabe Y.
Published: May 2018

Membrane fouling can be divided into two types: reversible fouling and irreversible fouling. The former can be easily canceled by physical cleaning (e.g., backwashing) while the latter needs chemical cleaning to be mitigated. For more efficient use of membranes, the control of irreversible membrane fouling is of importance. In this study, the effectiveness of pre-coagulation/sedimentation on irreversible membrane fouling was investigated, based on the pilot-scale operation of the membrane unit installed at an existing water purification plant. The membrane employed was a low-pressure ultrafiltration (UF) membrane made of polysulfone and having a molecular weight cut-off of 750,000 daltons. Although pre-coagulation/sedimentation significantly mitigated membrane fouling mainly through the reduction of reversible membrane fouling, the degree of irreversible fouling was not reduced by the pre-treatment. This was because the irreversible fouling observed during this study was mainly attributed to polysaccharides/protein like fractions of organic substances that cannot be efficiently removed by coagulation/sedimentation. Aluminium used as coagulant was thought to cause irreversible fouling to some extent but did not in the pilot operation, which could probable be explained by the fact that coagulation was conducted at relatively high pH (7.0) in this study.
Function of dynamic membrane in self-forming dynamic membrane coupled bioreactor
Authors: Wu Y. , Huang X. , Wen X. , Chen F.
Published: May 2018

The Self-Forming Dynamic Membrane Coupled Bioreactor (SFDMBR), which uses coarse pore-sized material to separate solid and liquid in bioreactors, has some advantages compared with MBR using micro-/ultra-filtration membranes, for example, low module cost and high flux. The cake layer and gel layer formed on the surface and in the pores of the material during filtration played an important role, called self-forming dynamic membrane (DM), which mainly consisted of activated sludge. In this study, the function of DM in pollutant removal was investigated. It was found that DM could remove some organic matter (12.6 mg L−_rm;1 on average) and total nitrogen (3.01 mg L−_rm;1 on average) in the supernatant. Colloids and organic nitrogen were partly removed by DM while DOC, ammonia nitrogen and nitrate nitrogen removal by DM varied from negative to positive, which resulted from the combination of various biological activities, e.g. nitrification, biological utilization and so on. DO concentration in DM decreased with the depth and reached zero at about 1.5–2.5 mm depth. The organic degradation activity and nitrification activity of the biomass suspended in the bioreactor were higher than those of the biomass in the cake layer, which might be caused by the low DO concentration and low organic pollutant content in DM.
Performance of individual fibers in a submerged hollow fiber bundle
Authors: Yeo A. , Fane A.G.
Published: May 2018

Hollow fiber membranes are popular as they have a high specific membrane area. To take advantage of this, it is necessary to pack the fibers into closely packed bundles. The fibers in different positions in the bundle behave differently as they are exposed to different hydrodynamic conditions. In this paper, a ‘model’ bundle of 9 fibers was tested in a setup which provides flow measurement from individual fibers and the same suction pressure in each fiber. The parameters studied were packing density, cross flow velocity, feed concentration and bubbling. It was found that a low cross flow velocities, high pressures and high feed concentrations, the surrounded (center) fiber performed very poorly compared to the fibers at the corner and the sides. Under these conditions, the overall performance of the bundle was much worse that of a single fiber.
Microbial community in biofilm on membrane surface of submerged MBR: effect of in-line cleaning chemical agent
Authors: Lim B.-R. , Ahn K.-H. , Song K.-G. , Cho J.W.
Published: May 2018

The objective of this study was to investigate the change in microbial community pattern with the effect of cleaning agent using a quinone profile that is used for membrane in-line chemical cleaning in SMBR. The dominant quinone types of biofilm were ubiquinone (UQs)-8, -10, followed by menaquinone (MKs)-8(H4), -7 and UQ-9, but those of suspended microorganisms were UQ-8, UQ-10 followed by MKs-8(H4), -7 and -11. Both UQ and MK contents decreased with increasing NaClO dosage and it seems that there is more resistance from UQ compared to MK. In addition, COD and DOC concentrations increased with increasing NaClO dosage up to 0.05 g-NaClO/g-SS. The organic degradation performance of the microbial community in the presence of NaClO was impaired. The present study suggested that larger added amounts of NaClO caused an inhibition of organic degradation and cell lysis.
Hybrid membrane operations in water desalination and industrial process rationalisation
Authors: Drioli E. , Di Profio G. , Curcio E.
Published: May 2018

Membrane science and technology are recognized today as powerful tools in resolving some important global problems, and developing newer industrial processes, needed from the imperative of sustainable industrial growth. In seawater desalination, for resolving the dramatic increase of freshwater demand in many regions of the world, membrane unitary operations or the combination of some of them in integrated systems are already a real means for producing water from the sea, at lower costs and minimum environmental impact, with a very interesting prospective in particular for poor economy countries. However, membranes are used or are becoming used in some important industrial fields, for developing more efficient productive cycles, with reduced waste of raw-material, reducing the polluting charge by controlling byproduct generation, and reducing overall costs. In the present paper, other than for seawater desalination applications, some industrial applications where membrane technology has led already to match the goal of process intensification are discussed.
Elimination of aromatic surfactants from municipal wastewaters: comparison of conventional activated sludge treatment and membrane biological reactor
Authors: Terzic S. , Matosic M. , Ahel M. , Mijatovic I.
Published: May 2018

Behaviour of anionic surfactants of linear alkylbenzene sulphonates (LAS) type and non-ionic surfactants of nonylphenol polyethoxylate (NPnEO) type was studied in the conventional mechanical/biological sewage treatment plant (STP) as well as using a membrane biological reactor (MBR). LAS and NPnEO were determined using high performance liquid chromatography (HPLC) equipped with spectrofluorimetric detection. Liquid chromatography/tandem mass spectrometry (LC/MS/MS) was used for identification and quantification of stable metabolites, including nonylphenol (NP), nonylphenol monoethoxylate (NP1EO), nonylphenol diethoxylate (NP2EO) and nonylphenoxy carboxylic acids (NPnEC). The study showed that aromatic surfactants belong to the most prominent constituents in the examined municipal wastewaters with typical LAS and NPnEO concentrations of 2–10 mg/L and 0.1–0.5 mg/L, respectively. The removal of aromatic surfactants in conventional STP showed well-known features reported in the literature, including an efficient microbial transformation of the parent molecules and formation of stable metabolic products. The elimination efficiency of aromatic surfactants using the MBR unit was higher than that in the conventional STP, while the composition of recalcitrant nonylphenolic residues in the effluent seems to be ecotoxicologically more favourable due to the lower contributions of the lipophilic metabolites.
A pilot-scale photocatalyst-membrane hybrid reactor: performance and characterization
Authors: Ryu J. , Choi W. , Choo K.-H.
Published: May 2018

We developed and tested a pilot-scale photocatalyst-membrane hybrid reactor for water treatment. The performance of the pilot-scale reactor was evaluated by monitoring the degradation efficiency of several organic pollutants and the membrane suction pressure at different operating conditions. The concentration of humic acids rather increased in the initial period of UV illumination and then decreased gradually, which could be ascribed to the photoinduced desorption of humic acids from the TiO2 surface. The decoloring rate of methylene blue was faster than that of rhodamine B, whereas the order of mineralization rates of the dyes was reversed. 4-chlorophenol of 100 ppb was fully degraded under UV irradiation in 2 hours, which suggests that this hybrid reactor would be more suitable in removing micropollutants in water. The reactor was operated with either continuous or intermittent suction mode. In a continuous suction mode, the formation of TiO2 cake layers on the membrane surface occurred and caused a substantial increase in suction pressure. However, no further fouling (or suction pressure build-up) took place with an intermittent suction mode with the 9-min suction and 3-min pause period. The photocatalyst-membrane hybrid reactor system developed in this study could be an attractive option for controlling micropollutants in water.
Anaerobic bio-hydrogen production using pre-heated river sediments as seed sludge
Authors: Zuo J. , Zuo Y. , Zhang W. , Chen J.
Published: May 2018

Anaerobic bio-hydrogen production is the focus in the field of bio-energy resources. In this paper, a series of batch experiments were conducted to investigate the effects of several factors on anaerobic bio-hydrogen producing process carried out by pre-heated river sediments. The results showed that several factors such as substrate and its concentration, temperature and the initial pH value could affect the anaerobic bio-hydrogen production in different levels. At 35°C and the initial pH of 6.5, using glucose of 20,000mg COD/L as substrate, the highest hydrogen production of 323.8ml-H2/g TVS in a 100ml batch reactor was reached, the specific hydrogen production rate was 37.7ml-H2/g TVSh, and the hydrogen content was 51.2%. Thereafter using the same pre-heated river sediments as seed sludge, continuous anaerobic bio-hydrogen production was achieved successfully in a lab-scale CSTR with gas-separator. At the organic loading rate of 36kg COD/m3d, the highest hydrogen production was 6.3–6.7l-H2/l-reactord, the specific hydrogen production was 1.3–1.4mol-H2/mol-glucose, and the hydrogen content in the gas was 52.3%. The effluent of the bio-reactor contained some small molecular organics, mainly including ethanol, acetate, butyrate and their molar proportion is 1 : 1 : 0.6.
Anaerobic treatment of Hong Kong leachate followed by chemical oxidation
Authors: Fang H.H.P. , Lau I.W.C. , Wang P.
Published: May 2018

Landfill leachate of Hong Kong was first treated by the upflow anaerobic sludge blanket (UASB) process. At 37°C, pH 7.1–8.5 and a HRT of 5.1–6.6 days, the process removed 66–90% of COD in the leachate for loading rates of 1–2.4g-COD/lday depending on the strength of landfill leachate. The final effluent contained 1440–1910mg-COD/l and 70–91mg-BOD/l. About 92.5% of the total COD removed was converted to methane and the rest was converted to biomass with an average net growth yield of 0.053g-VSS/g-COD-removed. The granules developed in the UASB reactor were 0.5–1.5mm in size and exhibited good settleability. The UASB effluent was then further polished by two oxidation processes. The UASB-ozonation process removed 93.0% of the 12900mg/l of COD from the raw leachate. The UASB-Fenton-ozonation process improved the COD removal efficiency to 99.3%. The final effluent had only 85mg/l of COD and 10mg/l of BOD5. Ozonation was most effectively conducted at pH 7–8 with the addition of 300mg/l of H2O2 and for the duration of 30min. Ozonation also significantly improved the biodegradability of the organic residues. Nearly 50% of these residues could be used as carbon source in denitrification.
Emission of greenhouse gases from constructed wetlands for wastewater treatment and from riparian buffer zones
Authors: Mander Ü. , Teiter S. , Augustin J.
Published: May 2018

We measured N2O, CH4 and CO2 fluxes in horizontal and vertical flow constructed wetlands (CW) and in a riparian alder stand in southern Estonia using the closed chamber method in the period from October 2001 to November 2003. The average rates of N2O, CH4 and CO2 emission from the riparian gray alder stand were from −0.4 to 58μg N2O-N m−2h−1 and 0.1–265μg CH4-C m−2h−1, 55–61mg CO2-C m−2h−1, respectively. The average N2O-N emission from the microsites above the inflow pipes of horizontal subsurface flow (HSSF) CWs was 6.4–31μg N2O-N m−2h−1, whereas the outflow microsites emitted 2.4–8μg N2O-N m−2h−1. In vertical subsurface flow (VSSF) beds the same value was 35.6–44.7μg N2O-N m−2h−1. The average CH4 emission from the inflow and outflow microsites in the HSSF CWs differed significantly ranging from 640 to 9715 and from 30 to 770μg CH4-C m−2h−1, respectively. The average CO2 emission was somewhat higher in VSSF beds (140–291mg CO2-C m−2h−1) and at inflow microsites of HSSF beds (61–140mg CO2-C m−2h−1). The global warming potential (GWP) from N2O and CH4 was comparatively high in both types of CWs (4.8±9.8 and 6.8±16.2 t CO2 eq ha−1 a−1 in the HSSF CW 6.5±13.0 and 5.3±24.7 t CO2 eq ha−1 a−1 in the hybrid CW, respectively). The GWP of riparian alder forest from both N2O and CH4 was relatively low (0.4±1.0 and 0.1±0.30 t CO2 eq ha−1 a−1, respectively), whereas the CO2-C flux was remarkable (3.5±3.7 tha−1 a−1). The global influence of CWs is not significant. Even if all the global domestic wastewater were treated by wetlands, their share in the trace gas emission budget would be less than 1%.
Rethinking sewage treatment by enhancing primary settling with low-dosage lime
Authors: Ramadori R. , Marani D. , Renzi V. , Passino R. , DiPinto A.C.
Published: May 2018

This work presents a thorough fractionation of COD in raw sewage, followed by pilot plant coagulation tests with low-dosage lime (pH 9). Through a physical separation (sieving and crossflow filtration) total COD in the raw sewage was partitioned among eight size fractions in the range of 150–0.02μm. In addition, respirometric tests were performed to measure the biodegradability of the different size fractions. More than 60% of COD was associated with settleable and supracolloidal particles (size >1μm), which are characterised by slow biodegradability. Coagulation with lime increased COD removal efficiencies in the primary treatment from typical 30–35%, up to 65–70%, suggesting that lime may induce the almost complete removal of the slowly settling, slowly biodegradable supracolloidal particles in the primary treatment. On the basis of these results a non-conventional sewage treatment scheme is proposed, considering that there is plenty of space for improving primary treatment efficiency through sewage coagulation. Higher primary treatment efficiency may present several advantages, including lower aeration energy in the subsequent biological unit and higher energy recovery from sludge digestion.
Activated sludge image analysis system: monitoring settleability and effluent clarity
Authors: Jenné R. , Banadda E.N. , Smets I.Y. , Bamelis A. , Verdickt L. , Impe J.F. Van
Published: May 2018

A fully automized image analysis procedure is presented for fast and reliable characterization of the activated sludge composition. In previous research, relations between filament abundance and floc shape on the one hand, and the Sludge Volume Index on the other hand were sought. This work aims at demonstrating the use of the image analysis information as an indication for the amount of suspended solids in the effluent.
Understanding the mechanisms of thermal disintegrating treatment in the reduction of sludge production
Authors: Camacho P. , Ginestet P. , Audic J.-M.
Published: May 2018

Among the technologies aimed at reducing sludge production, the combination of thermal treatment at 95°C of sludge and the activated sludge process is a promising route. The feasibility of such a combined process is demonstrated (up to 60% sludge reduction) and the impacts of operating conditions on its efficiency are presented. Major emphasis was put on understanding the complex phenomena occurring within the thermal treatment: release and biodegradability of sludge organic matter, impact on the biological activity (decay, maintenance requirements, etc.). These effects were taken into account for the development of an ASM1-based model. Comparison between the modeling approach and experimental data (continuous and batch) showed that thermal treatment had three major issues partly explaining the reduction of sludge production: (i) a low release of organics; (ii) an immediate and reversible biological inactivation associated with additional maintenance energy requirements; and (iii) a potential inert production.
Treatment of nanosized TiO2-containing wastewater by simultaneous electrocoagulation/electrofiltration
Authors: Yang G.C.C. , Chuang C.C.
Published: May 2018

In this work, a simultaneous electrocoagulation/electrofiltration (EC/EF) treatment module was employed to treat nanosized TiO2-containing wastewater. Nanosized TiO2-containing wastewater was obtained and treated by a self-designed EC/EF treatment module. To evaluate the performance of this novel treatment module, the effects of electric field strength (EFS), transmembrane pressure (TMP), and crossflow velocity (CV) on permeate qualities were investigated. Permeate qualities of concern included pH, turbidity, conductivity, chemical oxygen demand (COD), and total organic carbon (TOC). A full factorial design of experiments was adopted in this work. First, by keeping TMP and CV constant the effects of EFS on permeate qualities were studied. In this set of testing, it was noticed that an application of electric field greatly increased the filtration rate, which was further influenced by the magnitude of EFS. In all cases, the filtration rate decreased as the treatment time elapsed due mainly to fouling of the membrane. Further tests were conducted to study the effects of TMP on permeate qualities by keeping EFS and CV constant. Finally, the effects of CV on permeate qualities were studied by keeping EFS and TMP constant. It was found that the optimal operating conditions would be electric field strength of 166.7V/cm, transmembrane pressure of 1kgf/cm2, and crossflow velocity of 0.22cm/s. Under such conditions, permeate would have the following qualities: (1) pH, 6.32; (2) turbidity, 2.41NTU; (3) conductivity, 15.11μS/cm; (4) COD, 100.0mg/L; and (5) TOC, 512.6mg/L.
Performance improvement of hybrid membrane bioreactor with PAC addition for water reuse
Authors: Liu Y. , Wang L. , Wang B. , Cui H. , Zhang J.
Published: May 2018

A study was carried out on a hybrid (AS-SBF) membrane bioreactor (HMBR) for the municipal wastewater reclamation and reuse at Chengfengzhuang WWTP in Daqing City, Heilongjiang Province. It was found that the effects of DO and water temperature on performance of the HMBR was significant. Under the conditions of water temperature in range of 10–14°C, pH of 6.6–7.0, DO of 4–6mg/l and HRT of 7h, the HMBR exhibited removal efficiencies for CODcr, BOD5, NH3-N and TN of 96.7%, 98.9%, 93.7% and 60.5% respectively. The turbidity of effluent from HMBR was below 1NTU. The effluent of HMBR meets the standard of wastewater reclamation for oil exploitation. PAC was added into the bioreactor at the second operating stage, in order to further research parameters variation. The flux was improved by 53.2%, compared to the membrane without PAC-addition, due to formation of a PAC pre-coat layer on the membrane surface, with lots of advantages such as larger granules, higher porosity, non-compressibility, higher filterability and easy removal, compared with pure biomass layer. In addition, the performance of HMBR was further improved, due to adsorption and degradation of SMPs, the average removal of CODcr and TN was further improved by 5.1% and 13.5% respectively. Biomass in the HMBR was quantitatively measured, of which the biofilm played a major role in pollutants removal.
Optimization of operational factors of a membrance bioreactor with gravity drain
Authors: Zheng X. , Liu J.X.
Published: May 2018

A new membrane bioreactor with gravity drain for municipal wastewater treatment was tested and its operational factors were investigated in this study. These factors include pressure head, MLSS, aeration intensity (an air flow rate per unit floor area) and temperature. Results of batch experiments showed that a critical pressure head of the MBR was 0.85–1.5m-H2O. At a pressure head of 0.85m-H2O, statistical analysis of batch experiments showed that aeration intensity significantly affected membrane flux, and the MLSS had no impact on membrane flux under a temperature of 22.0±1.0°C. Results of the long-term continuous experiment showed that temperature significantly affected membrane flux. The impact of temperature on membrane flux in this case was about 4–10 times of that analyzed by using a classical cake layer model. During this experiment, the average removal efficiencies of COD, BOD5 and NH4+-N were over 85%, 97% and 94%, respectively.
Denitrification with polycaprolactone as solid substrate in a laboratory-scale recirculated aquaculture system
Authors: Boley A. , Müller W.-R.
Published: May 2018

A denitrification system based on the biodegradable polymer Poly-ɛ-Caprolactone (PCL) was tested in a laboratory-scale recirculated aquaculture system with eels in comparison to a reference system without denitrification. The experiments were conducted with fluidized bed reactors in two parallel systems to examine the feasibility and performance of the process and to observe the condition of fishes by measuring weight gain during the test-period. The most evident effect of the system with denitrification was the low nitrate concen-tration compared with the untreated reference system. A further advantage was the stability of the pH in the systems with denitrification whereas pH of the untreated water decreased due to nitrification. All over the test-period the eels showed a similar weight gain in both systems.
Chemical phosphorus removal model based on equilibrium chemistry
Authors: Takács I. , Murthy S. , Fairlamb P.M.
Published: May 2018

Regulations in many regions of the world require total phosphorus (TP) levels lower than 0.10mgP/L (100μgP/L) in effluents, resulting in the need to achieve very low ortho-phosphate (OP) concentrations. Chemical precipitation is a widely used technology for controlling effluent OP discharge, either on its own or supplementing biological methods. The various chemical and physico-chemical mechanisms that result in extremely low residual OP levels are complex and depend on pH. In practice, engineering calculations frequently use an empirical precipitation model. This model requires pH as input and predicts the lowest achievable OP residual of 35μgP/L at a narrow optimum pH of 6.9 – 7.0, when an excess of ferric is added. The model has been combined with a biokinetic and weak acid/base chemistry based pH model, to allow accurate prediction of pH, OP residuals and chemical sludge production. Analysis of effluent data from the Blue Plains plant shows that residuals as low as 10μgP/L OP can be achieved regularly, over a wider pH range. The precipitation model was recalibrated to match the newly available data. Subsequently it was compared with a new, mechanistic precipitation model based on solubility and dissociation constants for actual chemical compounds. The need for more accurate measurement of extremely low OP concentrations and considering the role of organics, adsorption and coagulation in chemical phosphorus removal is demonstrated.
Kinetic, isotherm, and thermodynamic studies of the adsorption of dyes from aqueous solution by cellulose-based adsorbents
Authors: Wang Yixi , Zhao Linyan , Hou Juan , Peng Huili , Wu Jianning , Liu Zhiyong , Guo Xuhong
Published: May 2018

In this study, a highly efficient and eco-friendly porous cellulose-based aerogel was synthesized by grafting polyethyleneimine onto quaternized cellulose (PQC) to remove the anionic dye Congo Red (CR). The prepared aerogel had a good flexibility and formability. The adsorbents were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and elemental analysis. The results showed that there were many amino groups on CE/PQC aerogel and the structure was porous, which increased the adsorption capacity. The effects of initial concentration, adsorbent dose, contact time, temperature, and pH on the dye sorption were all investigated. The adsorption mechanism was also explored, including adsorption kinetics, adsorption isotherms and thermodynamic studies of adsorption. The results showed that the adsorption kinetics and isotherms fitted the pseudo-second-order kinetic model and Langmuir isotherm, respectively. The Langmuir isotherm revealed that the maximum theoretical adsorption capacity of the aerogels for CR was 518.403 mg g−1. The thermodynamic parameters including Gibbs free energy change (ΔG0), enthalpy change (ΔH0) and entropy change (ΔS0), showed the adsorption process was exothermic and spontaneous. These results imply that this new absorbent can be universally and effectively used for the removal of dyes from industrial textile wastewater.
Ecodesign: um caminho para a sustentabilidade ambiental na indústria moveleira
Authors: Bezerra Mirna Andrade , Silva Elaine Aparecida da , Moita Neto José Machado
Published: May 2018

O ecodesign é um processo que objetiva reduzir e/ou mitigar os impactos ambientais de produtos durante todo o seu ciclo de vida. Este trabalho teve o objetivo de identificar a viabilidade de implantação do ecodesign em uma indústria do setor moveleiro localizada na cidade de Teresina-PI. A pesquisa foi realizada com base na norma da ABNT NBR ISO 14006:2011 que trata sobre as diretrizes para incorporar o ecodesign, sendo dividida em três fases: 1-Diagnóstico, 2-Definição de móveis, 3-Identificação de possibilidades de implantação do ecodesign. Foram selecionadas e analisadas as etapas de fabricação de três modelos de cadeiras pertencentes ao mobiliário escolar do tipo adulto. As etapas do ciclo de vida dos produtos envolvem: aquisição de matérias-primas, planejamento dos produtos, design, produção e transporte. A indústria não possui Sistema de Gestão Ambiental (SGA), representando a realidade da maioria das indústrias moveleiras dessa cidade. Verificou-se uma quantidade maior de processos (nove etapas), matérias-primas, resíduos e componentes para a fabricação do modelo 3. O modelo 1 possui menos etapas de produção (total de seis), aquisição de matéria-prima no próprio estado, para este produto não foram utilizadas embalagens e após a fabricação direcionadas ao cliente. Nesta indústria, há possibilidades de implantação do ecodesign com adoção de melhorias na economia de matéria-prima, escolha de fornecedores que fabriquem materiais mais sustentáveis e duráveis. A indústria necessita desenvolver ações voltadas ao atendimento dos requisitos mínimos dispostos na ABNT NBR ISO 14001, a fim de conectar a gestão dos processos aos impactos ambientais negativos causados por esta atividade.
Crystal Engineering: Upcoming Paradigm for Efficacious Pulmonary Drug Delivery
Authors: Desai Preshita P. , Mapara Sanyat S. , Patravale Vandana B.
Published: May 2018

Background and objective: Pulmonary drug delivery has transformed over a past few decades from
being a platform for local pulmonary disease treatment to systemic drug delivery opportunities. In case of pulmonary
delivery systems, particle properties are critical as they affect inhalation efficacy, pulmonary deposition,
drug delivery and overall performance. With this in view, particle engineering has emerged as an advanced science
that helps in designing of efficacious pulmonary delivery systems. Among various particle engineering
branches, crystal engineering is being extensively explored as it provides an opportunity to optimize particles at
morphological, physicochemical and molecular levels which are essential to understand the role of crystal engineering
in pulmonary drug delivery.

Methods:

A thorough literature survey in the field of crystal engineering approaches explored for pulmonary drug
delivery was conducted and the collected data was meticulously studied and summarized.

Results:

In the review, pulmonary system is discussed with respect to various sites for drug deposition in respiratory
tract, mechanism of drug deposition and clearance. Further, critical crystal parameters are discussed in-depth
and various crystal engineering methods are summarized with emphasis on their impact on pulmonary delivery.
Also, inhalation devices are overviewed to understand their performance in relation to crystal based pulmonary
formulations.

Conclusion:

The review enabled a detailed insight on crystal engineering approaches for design of pulmonary
delivery systems.
Development of Novel Therapeutics Targeting Isocitrate Dehydrogenase Mutations in Cancer
Authors: Sharma Horrick
Published: May 2018

Isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2) are key metabolic enzymes that catalyze
the conversion of isocitrate to α-ketoglutarate (αKG). IDH1 and IDH2 regulate several cellular processes,
including oxidative respiration, glutamine metabolism, lipogenesis, and cellular defense against
oxidative damage. Mutations in IDH1 and IDH2 have recently been observed in multiple tumors, including
gliomas, acute myeloid leukemia, myelodysplastic syndromes, and chondrosarcoma. IDH1 and
IDH2 mutations involve a gain in neomorphic activity that catalyzes αKG conversion to (R)-2-
hydroxyglutarate ((R)-2HG). IDH mutation-mediated accumulation of (R)-2HG results in epigenetic
dysregulation, altered gene expression, and a block in cellular differentiation. Targeting mutant IDH by
development of small molecule inhibitors is a rapidly emerging therapeutic approach as evidenced by
the recent approval of the first selective mutant IDH2 inhibitor AG-221 (enasidenib) for the treatment of
IDH2-mutated AML. This review will focus on mutant isocitrate dehydrogenase as a therapeutic drug
target and provides an update on selective and pan-mutant IDH1/2 inhibitors in clinical trials and other
mutant IDH inhibitors that are under development.
Backbone-Cyclized Peptides: A Critical Review
Authors: Rubin Samuel J.S. , Qvit Nir
Published: May 2018

Backbone-cyclized peptides and peptidomimetics integrate the biological activity and pharmacological
features necessary for successful research tools and therapeutics. In general, these structures
demonstrate improved maintenance of bioactive conformation, stability and cell permeability compared
to their linear counterparts, while maintaining support for a variety of side chain chemistries. We explain
how backbone cyclization and cycloscan techniques allow scientists to cyclize linear peptides with retained
or enhanced biological activity and improved drug-like features. We discuss head-to-tail (Cterminus
to N-terminus), building unit-to-tail, building unit-to-side chain, building unit-to-building unit,
and building unit-to-head backbone cyclization, with examples of building blocks, such as Nα-(ω-
thioalkylene), Nα-(ω-aminoalkylene) and Nα-(ω-carboxyalkylene) units. We also present several methods
for recombinant expression of backbone-cyclized peptides, including backbone cyclic peptide synthesis
using recombinant elements (bcPURE), phage display and induced peptidyl-tRNA drop-off.
Moreover, natural backbone-cyclized peptides are also produced by cyanobacteria, plants and other organisms;
several of these compounds have been developed and commercialized for therapeutic applications,
which we review. Backbone-cyclized peptides and peptidomimetics comprise a growing share of
the pharmaceutical industry and will be applied to additional problems in the near future.
Conversion of Protein Active Regions into Peptidomimetic Therapeutic Leads Using Backbone Cyclization and Cycloscan – How to Do it Yourself!
Authors: Rubin Samuel J.S. , Tal-Gan Yftah , Gilon Chaim , Qvit Nir
Published: May 2018

Protein-protein Interactions (PPIs) are particularly important for controlling both physiologic
and pathologic biological processes but are difficult to target due to their large and/or shallow interaction
surfaces unsuitable for small molecules. Linear peptides found in nature interact with some PPIs,
and protein active regions can be used to design synthetic peptide compounds for inhibition of PPIs.
However, linear peptides are limited therapeutically by poor metabolic and conformational stability,
which can compromise their bioactivity and half-life. Cyclic peptidomimetics (modified peptides) can
be used to overcome these challenges because they are more resistant to metabolic degradation and can
be engineered to adopt desired conformations. Backbone cyclization is a strategy that we developed to
improve drug-like properties of linear peptide leads without jeopardizing the integrity of functionally
relevant side-chains. Here, we provide the first description of an entire approach for developing backbone
cyclized peptide compounds, based upon two straightforward ‘ABC’ and ‘DEF’ processes. We
present practical examples throughout our discussion of revealing active regions important for PPIs and
identifying critical pharmacophores, as well as developing backbone cyclized peptide libraries and
screening them using cycloscan. Finally, we review the impact of these advances and provide a summary
of current ongoing work in the field.
The Hydrocarbon Staple & Beyond: Recent Advances Towards Stapled Peptide Therapeutics that Target Protein-Protein Interactions
Authors: Hillman Robert A. , Nadraws Jonathan W. , Bertucci Michael A.
Published: May 2018

Anomalous protein-protein interactions (PPIs) have been correlated to a variety of disease
states, such as cancer, infectious disease, neurological disorders, diabetes, endocrine disorders and cardiovascular
disease. Stapled peptides are an emerging intervention for these PPIs due to their improved
structural rigidity and pharmacokinetic properties relative to unstapled peptides. This review details the
most recent advances in the field of stapled peptide therapeutics, including the increasing variety of PPIs
being targeted and types of peptide staples being employed.
In silico Molecular Docking and ADME Studies of 1,3,4-Thiadiazole Derivatives in Relation to in vitro PON1 Activity
Authors: Sever Belgin , Kucukoglu Kaan , Nadaroglu Hayrunnisa , Altıntop Mehlika Dilek
Published: May 2018

Background: Paraoxonase 1 (PON1) is a paraoxonase, arylesterase and lactonase associated
with protection of lipoproteins and cell membranes against oxidative modification.

Objective:

Based on antioxidative properties of PON1 and significance of 1,3,4-thiadiazoles in
pharmaceutical chemistry, herein we aimed to evaluate the potentials of 1,3,4-thiadiazole derivatives as
PON1 activators.

Methods:

2-[[5-(2,4-Difluoro/dichlorophenylamino)-1,3,4-thiadiazol-2-yl]thio]acetophenone derivatives
(1-18) were in vitro evaluated for their activator effects on PON1 which was purified using
ammonium sulfate precipitation (60-80%) and DEAE-Sephadex anion exchange chromatography.
Molecular docking studies were performed for the detection of affinities of all compounds to the active
site of PON1. Moreover, Absorption, Distribution, Metabolism and Excretion (ADME) properties of all
compounds were also in silico predicted. In silico molecular docking and ADME studies were carried
out according to modules of Schrodinger’s Maestro molecular modeling package.

Results:

All compounds, particularly compounds 10, 13 and 17, were determined as promising PON1
activators and apart from compound 1, all of them were detected in the active site of PON1. Besides,
ADME results indicated that all compounds were potential orally bioavailable drug-like molecules.

Conclusion:

PON1 activators, compounds 10, 13 and 17 stand out as potential drug candidates for
further antioxidant studies and these compounds can be investigated for their therapeutic effects in
many disorders such as atherosclerosis, diabetes mellitus, obesity, chronic liver inflammation and many
more.