bluuebunny/crossref_metadata_2025 huggingface dataset:
An optimal magnetite immobilized Pseudomonas- putida 5-x cellsystem for Cu2+ removal from industrial waste effluent
Authors: Wang L. , Chua H. , Wong P. K. , Lo W. H. , Yu P. H. F. , Zhao Y. G.
Published: May 2018

An optimal magnetite immobilized Pseudomonas putida 5-x cell system was developed to remove Cu2+ from industrial waste effluent. Cu2+ adsorption capacity of P. putida 5-x cultured in sulphate-limiting medium (SLM) was minimum in early log growth phase, and reached maximum in late stationary growth phase or early death phase. Pretreated cells by 0.6 N HCl could greatly enhance the adsorption capacity of biomass up to 85.6 mg/g and had no significant effect for the loss of P. putida 5-x cells during the pretreatment. In a semi-continuous biosorption system, the removal efficiency of Cu2+ from wastewater reached 96%, and recovery efficiency of Cu2+ was 95%, and the concentration in the recovery solution was 1.4 g/L using 0.6 N HCl as eluant. The mechanism of Cu2+ adsorption by this type of biomass was studied by using the technique of transmission electron microscopy (TEM). Degradation of a peptidoglycan layer on the cell surface was observed after acidic pretreatment, but no further degradation appeared after the adsorption-desorption cycle. TEM and X-ray analysis also showed that Cu2+ was mainly accumulated on the cell surface, so it was effectively desorpted by acidic treatment in the desorption process. The process of adsorption obeyed the Freundlich isotherm.
Assessment of fish culture water improvement through the integration of hydroponically grown lettuce
Authors: Chaves P.A. , Laird L.M. , Sutherland R. , Beltrão J.
Published: May 2018

Water quality improvement through the integration of hydroponically grown lettuce into fish culture systems was assessed and nutrient concentration monitored throughout the production cycle. The experimental work consisted of two fish culture systems. One integrated with lettuce and a conventional fish culture system (without lettuce), was replicated two times. Fish were fed four times daily 1.2% of total biomass with a high protein (45%) feed content. Systems water renewal were calculated based on a mass balance approach for nitrates which is likely to accumulate beyond recommended levels for fish culture. Apart from iron, as iron chelate which was weekly supplemented to concentration levels of 2mg/l, all the other nutrients resulted from the fish culture water. Water samples were taken on a regular basis throughout the production cycle and results compared. Results suggest that through the incorporation of lettuce into the system, considerable water savings can be achieved where nitrates concentration was 20–27% less in the integrated system.
Taste and odour removal from an urban groundwater establishment – a case study
Authors: Ortenberg E. , Groisman L. , Rav-Acha C.
Published: May 2018

A deep groundwater well was established in a village near Tel-Aviv, in order to supply drinking water for its 30,000 inhabitants. Although all water characteristics were within the range permitted by the Israeli regulations, operators received complaints about a funny taste and a rotten-egg odour in the water. This was attributed to the presence of 0.38 mgL–1 hydrogen sulfide. Removing the odour by the usual method of aeration was impossible because of the populated surroundings. Therefore it was decided to examine chemical oxidants for taste and odour removal. A treatment with 8 mgL–1 of chlorine successfully oxidized hydrogen sulfide but the complaints continued. This was attributed to the formation of elemental sulfur, whichis converted into polysulfide that may hydrolyze to regenerate the odourous hydrogen sulfide. Treatment with 2 mgL–1 of chlorine dioxide successfully eliminates odour completely, but produces chlorite and chlorate which are above the permitted levels. A partial solution to this problem was found by a consequential treatment with 2 mgL–1 of ClO2 for 10 min. followed by 1.5 mgL–1 of chlorine (30 min.). In this case the chlorite is reduced substantially to be within the permitted level. In addition, such treatment regenerates some of the chlorine dioxide thereby increasing its residual. The odourous H2S can also be eliminated with 3 mgL–1 of ozone. Advantages and disadvantages of the above treatments are discussed.
Biomonitoring marine environmental quality at the level of gene-expression – testing the feasibility of a new approach
Authors: Sultan A. , Abelson A. , Bresler V. , Fishelson L. , Mokady O.
Published: May 2018

Differential-display PCR (DD-PCR), a comparative method for detecting alterations in the expression pattern of unknown genes, was applied to identify markers for environmental pollution of the coastal marine environment, in Donax trunculus (Mollusca: Bivalvia). Bivalves collected from a site typified by industrial pollution were compared with bivalves collected from an unpolluted site. Additionally, bivalves from the unpolluted site were exposed in the laboratory to increasing levels of pollution. Multiple responsive fragments, including qualitative and quantitative differentials, were observed in both experimental designs. Fragment-specific primers may be designed for use in diagnostic amplifications, according to the sequence of selected differential fragments. This study is a first step toward the establishment of a marine warning and monitoring system based on the most basic level of biological response.
Ecological incidents in Northern Adriatic Karst (Croatia)
Authors: Gereš D. , Rubinič J. , Ožanić N.
Published: May 2018

In spite of growing efforts to preserve the quality of groundwater resources, accidental pollution is becoming increasingly frequent, resulting in long-lasting impact on the groundwater status. The consequences of ecological accidents are particularly expressed in karst regions, which are caused by the geological properties of the area where the groundwater aquifers are situated, as well as by hydrological circumstances which also influence the dynamic mechanisms of water flow and transportation of pollution in the karst environment. The paper stresses the hydrological component of karst aquifer function and the related role of hydrology in assessment of the hazards caused by accidental pollution and, once the accident has happened, in monitoring the situation and forecasting the possible impact on water resources. The analysis of ecological accidents in the karst has been made, based on the actual examples of accidents involving fuel substances recorded in the Northern Adriatic karst area in Croatia in the period from 1990 to 1998. The basic characteristics of the mechanism of water movement in the karst are presented from the hydrological standpoint, as well as the related risk of rapid transportation of pollutants into the parts of the aquifers used for water supply. The paper also contains proposals for possible approaches to protection of particularly valuable water resources in the karst from accidental pollution occurring in road transport.
The efficacy of long-lasting residual drinking water disinfectants based on hydrogen peroxide and silver
Authors: Pedahzur R. , Katzenelson D. , Barnea N. , Lev O. , Shuval H.I. , Fattal B. , Ulitzur S.
Published: May 2018

The aim of the present work was to evaluate the disinfectant capacity and the possible fields of application of a combined silver and hydrogen peroxide (HP) water disinfectant. The findings demonstrated the high bactericidal action of silver (on E. coli) and its relatively ineffective virucidal effect (on MS-2 phage).

HP was found to have a small bactericidal effect and a mild virucidal one. When combined, silver and HP usually exhibited a synergistic action on the viability of E. coli and on the luminescence of recombinant luminescent E. coli. In some instances, the combined bactericidal effects were 1000-fold higher than the sum of the separate ones. No increased virucidal action was observed. The biocidal action of the combination generally increased with increasing temperature and pH, and decreased in secondary and tertiary effluents. The physiological effects and mechanisms of toxicity of HP, silver and their combinations, were assessed by monitoring the induction of stress promoters upon exposure to the active agents, and by assessing the sensitivity of E. coli mutated in major stress responses to HP, silver and their combinations. The results showed that HP induced a wide array of stress responses, that both silver and HP induced promoters regulated by the heat shock response, and that the dnaK promoter (regulated by the heat shock response) was synergistically induced. The mutant sensitivity tests showed that bacteria deficient in the ability to activate central cellular stress responses (SOS, heat shock, stationary phase, oxidative) were hypersensitive to both HP and silver. These results imply that cellular proteins, and possibly the DNA, are the cellular moieties chiefly affected. The above findings suggest that the potentiated effect of HP and silver is a metabolically dependant/related process that stems from a combination and/or accumulation of physiological effects exerted by the active ingredients.

The physico-chemical properties of the combined disinfectant, and its disinfection capacity, points to its potential application as a long-term secondary residual disinfectant for water of relatively high quality.
Study and monitoring of mucilage in the adriatic sea
Authors: Penna N. , Berluti S. , Penna A. , Ridolfi F.
Published: May 2018

The presence of large mucilaginous masses, referred to as mucilage or with the traditional term “dirty sea”, has led to serious problems for the tourism and fishing industries along the coast of the northern Adriatic Sea. Using a cable-guided telecamera, these masses were observed in situ from the water surface along the water column to the sea bottom, with the aim of better understanding the appearance of the mucilage, its formation and dispersion and the processes originated by phytoplankton involved in this phenomenon. Furthermore, we sought information to help explain the fact that the appearance of mucilage does not tend to lead to anoxia in the surrounding water and that the mucilage seemed to containhuge amounts of iron. The chemical-physical characteristics of mucilage samples and samples of the surrounding water were studied. Further studies of their composition were carried out to determine the levels of organic matter, organic carbon, carbohydrates and heavy metals.
Optical fiber bioluminescent whole-cell microbial biosensors to genotoxicants
Authors: Polyak B. , Bassis E. , Novodvorets A. , Belkin S. , Marks R.S.
Published: May 2018

Conservation of water resources calls for ever stricter regulatory measures and better monitoring systems. Whole-cell bacterial sensors have been genetically engineered to react to target toxicants by the induction of a selected promoter and the subsequent production of bioluminescent light through a recombinant lux reporter. In order to create a one-step assay, we have designed a new, self-contained, disposable optical fiber sensor module and a customized photodetector system that integrates these microorganisms. A photon-counting photomultiplier tube-based instrument was constructed. Optical fiber tip cores were covered with adlayer films consisting of calcium alginate containing bioluminescent bacterial sensors of genotoxicants. Multiplying these steps thickened the adlayer in increments, increasing the number of bacterial reporters attached to the optical fiber transducer. These whole cell optrodes are responsive to external traces of DNA damaging agents such as mitomycin C. Light production was shown to be dose-dependent and proportional to the number of bacterial layers.
Evaluation of surfactant efficiency in remediation on non aqueous phase liquid (NAPL) contaminated soils
Authors: Rubin H. , Zoller U. , Dveyrin D.
Published: May 2018

This study represents a possible approach for the determination of the parameters characterizing the efficiency of surfactant mix for the remediation of soil and aquifers contaminated by entrapped non aqueous phase liquid (NAPL). The method incorporates the performance of two sets of experiments and their appropriate analysis. In one set, called the “vessel experiments”, the CMC of the surfactant mix is determined. The second set of experiments is called the “flow experiments”. In this set of experiments soil columns are contaminated by entrapped NAPL. Water flows through these columns with various types of surfactant mix solutions. According to the soil permeabilityvariation and the dissolved NAPL concentration in the water leaving the soil column, the effect of the surfactant mix on the coefficient of mass transfer is determined.
PVA-coated activated carbon for aerobic biological treatment of concentrated refractory organic wastewater
Authors: Lim B.-R. , Hu H.-Y. , Goto N. , Fujie K.
Published: May 2018

The treatment characteristics of concentrated p-phenol sulfonic acid (PSA) wastewater in a submerged bioreactor and a solid phase bioreactor packed with ACP particles (polyvinyl alcohol particles coated with powered activated carbon) were compared experimentally. The changes in biomass and microbial community with the degradation of PSA at both bioreactors were also evaluated using microbial quinones as an index. Greater than 95% of influent PSA was mineralized at the solid phase bioreactor under the volumetric loading of PSA ranging from 0.3 to 1.8 kg-C·m-3·d-1 at the steady state, but less than 10% of the influent PSA was mineralized in the submerged bioreactor. The solid phase aerobic biological treatment process was more effective for the treatment of concentrated refractory chemicals such as PSA than the submerged bioreactor. The dominant quinone species in the solid phase bioreactor were ubiquinone-10 and menaquinone-8(H4), while those in the submerged bioreactor were ubiquinone-8 and menaquinone-8. This suggests hat different microbes had contributed to the degradation in the two bioreactors.
Effects of sludge settling characteristics in the BNR system
Authors: Yun Z. , Yo W. , Yi Y. , Choi S. , Choi E. , Min K.
Published: May 2018

Although the BNR system design assumes no sludge settling problems in the final settling tank, the fluctuation of daily loading and up to 40% of anaerobiosis in the BNR system would be considerable factors in determining the sludge settleability. The sludge volume index (SVI) is a classical parameter to examine the sludge settleability but it has a limited value to evaluate the overall settling characteristics. The extracellular polymer (ECP) content in sludge has long been considered as an indicator of biological flocculation in activated sludge process, but the skepticism on analytical accuracy limits the usage in settling study. This study focused on evaluating the BNR system performance related to the sludge settling characteristics under the controlled laboratory environment. A 5-stage BNR system (anaerobic-anoxic-3 stage oxic) was operated with the HRTs from 3.9 to 7.6 hours. In order to determine the sludge settling properties, both SVI and ECP content were monitored. The ECP contents in the sludge sample were measured by the slime-washing step followed by high-G centrifugation and sonication. The gel-electrophoresis was used to detect the DNA in the sonicated samples to determine the intracellular polymer contamination. It has been found that the anaerobiosis in the anaerobic and anoxic zone that consisted of 37% of reactor volume could not deteriorate the sludge settling properties even at the HRT of 3.9 hours. The SVI values of sludge taken from the reactor with the HRT of 7.2 hours averaged to less than 50 mL/gr. It was postulated that a fast settling sludge in the BNR system could not always ensure production of clear effluent. The sludge with very low SVI might not achieve a complete biological flocculation potential. In addition, the degree of denitrification in the BNR system could be related to the sludge settleability.
Phosphate removal from wastewater using spent alum sludge
Authors: Huang S.-H. , Chiswell B.
Published: May 2018

A small-scale continuous flow system, which allows recycling of effluent, has been set up to study the phosphate adsorption ability of air-dried alum sludge from wastewater effluent, and the variation of nitrogen species in wastewater associated with phosphate removal. Initial phosphate removal was rapid, with phosphate levels being reduced by approx. 55% in the first 20 minute of the experiment. The variation of nitrogen species present in the wastewater showed a negative correlation with the concentration of phosphate. Thus, the concentration of ammonia increased from 0 ppm to 16 ppm, while the concentration of nitrate increased from 0 ppm to 98 ppm in the first 20 minutes; nitrite concentrations were found to be insignificant. Very similar phosphate removal patterns and changes in nitrogen species concentrations were exhibited for different batches of alum substrate; the adsorption capacity of spent alum was found to be approx. 0.30–0.33 mg phosphate per 1 g of air-dried spent alum.
Research on low temperature thermo-chemical conversion to oil process for sewage sludge
Authors: He P. , Gu G. , Shao L. , Zhang Y.
Published: May 2018

The process of low temperature thermo-chemical conversion of municipal sewage sludge to oil is a new developing technology in developed countries, which is developed based on some poor fuels processing process in recent years. The process has the advantages of reasonable thermal energy recovery (the whole process is a net thermal energy exporting process), suitable cost and less secondary pollutants. This research included the reaction conditions versus the converted products distributions, the reaction conditions versus the ratio of the process thermal energy input and output, exploring of reaction mechanisms, creating of reaction kinetics models. These results contribute not only to having a clear understanding about the technological features and evaluating the prospectives of technological development, but also provide a sound basis for the technological development on a larger scale. It is concluded that: 1) the sludge treatment process is a net thermal energy producer. 2) The optimal conversion temperature is 270°C, referring to making energy recovery ratio maximum. 3) The parameters of simple conversion reaction kinetics are n=2, A=8.5 S-1 and E=37.9 KJ/mol. 4) The secondary pollutants of the process can be effectively controlled. 5) The investment intensity of the process could be similar to that of the sewage sludge incineration process, and the operational economics of the process are obviously superior to those of the sewage sludge incineration process. The research results show that the technical-economic feasibility of low temperature thermo-chemical conversion process is favorable, because the reaction conditions are more moderate and the separation process of the products is more easily realized.
Wastewater control in welding electrode manufacturing - a case study
Authors: Tünay O. , Kabdasli I. , Orhon D.
Published: May 2018

Metal finishing plants, although the wastewaters and treatment schemes for this category are well defined, require a case by case evaluation to find appropriate solutions and to solve specific problems. In this paper, a case study conducted on a welding electrode plant is presented. The wastewater sources were surface cleaning, copper plating and soap solutions used for drawing which were frequently included in waters. The plant was subjected to pretreatment standards, which necessitated the control of sulfate and organic matter in addition to standard parameters of metals, oil, suspended solids etc. Following a source-based characterization, treatability studies were conducted to treat high concentration of sulfate, organic matter as well as heavy metals and oil-grease. The proposed treatment scheme involved separate treatment of copper bath for recovery, chemical oxidation for soap solutions, sulfate precipitation for sulfuric acid bath and application of hydroxide precipitation to proper combination of other wastewater sources.
Study of heterotrophic nitrifying bacteria from wastewater treatment systems treating acrylonitrile, butadiene and styrene resin wastewater
Authors: Hu T.-L. , Kung K.T.
Published: May 2018

In this study we investigated the population of heterotrophic nitrifying bacteria in three biological wastewater treatment systems treating acrylonitrile, butadiene and styrene (ABS) resin wastewater. In addition to isolating and identifying these bacteria, we examined the physiological properties of the isolates, particularly utilization of acrylonitrile and its derivatives. An enrichment process was employed to isolate heterotrophic nitrifying bacteria from sludge samples taken from three biological wastewater treatment systems. Thirteen isolates were obtained and four strains were identified as Alcaligenes sp., Acinetobacter sp., Xanthomonas sp. and Corynebacterium sp. Alcaligenes sp. and Corynebacterium sp. have already been reported as heterotrophic nitrifiers. To our knowledge, this is the first time Acinetobacter sp. and Xanthomonas sp. have been reported as heterotrophic nitrifiers. The heterotrophic nitrifying isolates used acrylonitrile and acrylamide as the sole carbon and nitrogen sources. Moreover, adding an extra carbon source enhanced the nitrification rate.
Characteristics of hydrogen production from bean curd manufacturing waste by anaerobic microflora
Authors: Mizuno O. , Ohara T. , Shinya M. , Noike T.
Published: May 2018

The hydrogen production from bean curd manufacturing waste by anaerobic microflora was investigated using batch experiments at 35 °C. The anaerobic microflora was obtained from fermented soybean-meals and maintained using a sucrose-limited medium in continuous culture. A solution of an organic substrate without solid component such as rough fiber in bean curd manufacturing waste was used for the experiments. After the inoculation, hydrogen production immediately occurred and almost ceased at 12 h. The final concentration of hydrogen in gas produced was 63% H2. During hydrogen production, carbohydrate was rapidly degraded while protein degradation was hardly observed, suggesting that carbohydrate was the main source of the hydrogen production. The hydrogen yield was 2.54 mol of H2 mol-1 of hexose utilized if hydrogen gas was produced from only carbohydrate degradation. At a carbohydrate concentration greater than 3,720 mg l-1, the rate of hydrogen production rate significantly decreased. The rate of alcohol production was remarkably increased with increasing carbohydrate while the rate of volatile fatty acid production was hardly changed. The results indicated that the metabolic pathway and the amount of hydrogen production would be significantly influenced by the carbohydrate concentration.
Complete treatment of swine waste by developing thermophilic oxic process
Authors: Lee C.-W. , Chiba N. , Nishimura O. , Yamada K. , Sudo R.
Published: May 2018

In this study, treatment characteristics of swine waste (90% water content) by thermophilic oxic process (TOP) were evaluated in bench scale and pilot scale experiments. In bench scale experiments, it was impossible to treat swine waste. As for the reason, the calories of swine waste were too low for water evaporation to take place. However, it could be treated by the addition of food oil as an assistant calorie source. When the swine waste BOD load was 3 kg·m-3·day-1, the aeration rate was 100L·m-3·min-1 and 120mL of food oil was added, 86% of carbon was converted to CO2 and 98% of the water was evaporated in one cycle. 90% of the total added swine waste (40kg) and virgin food oil (2kg) was removed as gases, 8% was accumulated in the reactor and 2% was drained in 60 days. The pilot scale reactor was designed based on the bench scale experiment results. TOP successfully reappeared in the pilot scale reactor, and swine waste was treated effectively.
Mass transfer phenomena in biofilm systems
Authors: Wäsche S. , Horn H. , Hempel D.C.
Published: May 2018

Mathematical models allow the simulation of microorganism growth and substrate transport in biofilm systems. Nevertheless there is still a lack of knowledge about the mass transfer of substrate in the boundary layer between biofilm and bulkphase.

Several biofilms were cultivated under different substrate and hydrodynamic conditions in a biofilm tube reactor. Oxygen concentration profiles were measured with oxygen microelectrodes in the biofilm and in the boundary layer. The thickness of the concentration layer was found to depend on surface structure which depends on the substrate loading and the hydrodynamic conditions during the growth phase of the biofilm. Biofilm density and maximum substrate flux were also influenced by growth conditions. An empirical function for the concentration layer thickness was formulated for biofilms grown under different conditions to describe transport phenomena in the boundary layer.
Performance of periodically operated-gas phase biofilters during transient loading conditions
Authors: Moe W.M. , Irvine R.L.
Published: May 2018

Most industrial processes and environmental remediation activities generate large volumes of air contaminated with volatile organic compounds (VOCs). In conventional biofilter operation, gaseous emissions contaminated with low concentrations of biodegradable VOCs are remediated by being passed continuously through packed beds. This paper describes how periodically operated biofilters can be designed as controlled, unsteady-state systems that destroy gas-phase contaminants. Periodic operation, previously limited to applications in wastewater treatment and soil remediation, increases an operator's ability to control the spatial distribution, physiological state, and “robustness” of the microbial communities established within a biofilter while minimizing uncertainties that often accompany design and operation of biological systems. Results are presented from toluene degrading biofilters that used a novel polyurethane foam packing medium. These studies demonstrate how controlled periodic operations can enhance contaminant removal during transient periods of elevated contaminant load.
Factors affecting phosphorus removal in two biofilter system treating wastewater from car-washing facility
Authors: Pak D. , Chang W.
Published: May 2018

A two-biofilter system operated under alternating anaerobic/aerobic conditions was tested to remove nutrient as well as organics from wastewater generated from car-washing facility. The wastewater was characterized by relatively low organic and high phosphorus content. The factors affecting phosphorus removal in the two-biofilter system were investigated. Operational parameters examined in this study were hydraulic retention time, organic, suspended solid and nitrogen loading rate. The factors affecting phosphorus removal in biological filter appeared to be influent COD, COD/T–P, BOD/COD, nitrogen, and SS/T–P. Nitrite and nitrate produced in the biofilter in aerobic condition affected phosphorus removal by the two-biofilter system. The biomass wasted during backwash procedure also affected total phosphorus removal by the system.
Optimising the A/O cycle for phosphorus removal in a submerged biofilter under continuous feed
Authors: Gonçalves R.F. , Rogalla F.
Published: May 2018

This work describes laboratory scale research about Enhanced Biological Phosphorus Removal (EBPR) in a submerged biofilter under Anaerobic/Oxic (A/O) alternation and continuous feed. Its main purpose is to detail the behaviour of the reactor throughout the anaerobic and the aerobic phases of the A/O cycle, to study the importance of the anaerobic phase in the selection of the EBPR bacteria in the biofilm and to evaluate the consumption and the importance of the organic substrate during the anaerobic phase. The mass balance over the Phosphorus (P) element indicates that long anaerobic phases (6 h) are more efficient than short ones (3 h) as a selector of EBPR bacteria in biofilms.

In both comparisons, thespecific mass of P released in a 6 h period represents almost 50% more than the amount of P release in the shorter period (3 h). However, the presence of rapidly biodegradable COD in the influent of the anaerobic phase is a more effective selector, more important than the duration of the anaerobic phase: by doubling the amount of acetic acid in the influent, a similar 50% increase of P-release can be achieved at short anaerobic periods of 3 h. The effect of the strategy adopted in this study, focusing on selecting EBPR bacteria in biofilm, is shown by the P levels of 4% (total P/SST) in the sludge removed from the BF by backwashing in all periods.
Adsorption and stabilization of nickel ions on fly ash/lime mixing
Authors: Ricou-Hoeffer P. , Héquet V. , Lécuyer I. , Le Cloirec P.
Published: May 2018

Experimental design methodology was used to define conditions for the adsorption and the stabilization of nickel ions (initial concentration of 500 mg.L-1) on coal fly ash/lime sorbent. This type of sorbent allows the reuse of by-products and increases the stabilization of metallic ions by lime addition. It was shown that the solution pH, the metal/adsorbent mass ratio, the type of fly ash used as sorbent, and the fly ash/lime mass ratio are the most influential factors. A set of parameters was finally obtained (pH 5, metal/adsorbent ratio of 0.01 g.g-1, fly ash/lime ratio of 4 g.g-1, fly ash with the lowest content of iron oxide) for which the removal of Ni2+ is 96% and the leaching 0.03% by permuted water and 0.2% by acid solution of pH 2.
Selective biosorption of lanthanide (La, Eu, Yb) ions by an immobilized bacterial biomass
Authors: Texier A.-C. , Andrès Y. , Le Cloirec P.
Published: May 2018

The removal of metallic ions La3+, Eu3+ and Yb3+ from aqueous solution by immobilized biomass of Pseudomonas aeruginosa was investigated in batch and column reactors. Batch studies consisted in kinetic measurements for lanthanum adsorption by biomass-chitosan beads. Results did not show a significant effect of the presence of bacteria into chitosan matrix on the lanthanum uptake. Then, laboratory-scale fixed-bed column experiments were carried out using biomass-entrapped polyacrylamide gel beads, which contained approximately 48% (dry weight basis) of biomass. The lanthanum sorption was dependent on the superficial liquid velocity based on empty column in the range 0.76–2.29 m.h-1. The removal of lanthanide cations (2 mM) at pH 5.0 and 0.76 m/h was 198 μmol.g-1 (dry biomass) for lanthanum, 167 μmol.g-1 for europium and 192 μmol.g-1 for ytterbium (±10%). These results are of the order of 1.7–2 times lower than those observed in batch systems with free bacterial cells. Column experiments with mixed-cationsolutions showed the following sequence of preferential biosorption: Eu3+ >Yb3+ >La3+.
Treatment of a 2,4-dichlorophenoxyacetic acid (2,4-D) contamined wastewater in a membrane bioreactor
Authors: Buenrostro-Zagal J.F. , Ramírez-Oliva A. , Caffarel-Méndez S. , Schettino-Bermúdez B. , Poggi-Varaldo H.M.
Published: May 2018

2,4-Dichlorophenoxyacetic acid (2,4-D) is used for commercial herbicides preparation. In Ecatepec, Mexico, there is an industrial plant that manufactures 2,4-D and other herbicides that discharges a low pH, high salinity and 2,4-D rich effluent: a very aggressive and toxic wastewater. This research aimed at acclimating a 2,4-D degrading culture from wild inocula, and implementing and determining the performance of an extractive membrane bioreactor (EMB) for 2,4-D removal from an effluent similar to that industrial wastewater. The experimental work consisted of two phases. In the first phase a mixed, aerobic microbial culture was acclimated to 2,4-D in submerged culture. In the second phase, a lab scale EMB was implemented. The acclimated culture was able to use 2,4-D as the sole source of carbon and energy with an optimum at pH = 8. Gram negative microorganisms predominated in the consortium. The culture growth in 2,4-D followed an Andrews-like substrate inhibition kinetic model with μmax = 0.06 1/h, Ks = 17 mg/L, Ki = 128 mg/L. The hydrophobic membrane had a partition coefficient membrane/water of 131 Laq/Lmembr, which suggested an important adsorption effect/solution in the membrane. The permeability coefficient determined at pH 0, 1 and 4 was practically independent of pH with an average value of 3.2=10-8 m/s. After inoculation, continuous, steady-state experiments were also run at influent 2,4-D concentration of 300 mg/L. The reactor showed 2,4-D unit reductions in the range of 110 to 120 mg 2,4-D/L lumen.h (32 to 34 mg/h.m2) at lumen retention times of 4.1 to 15 min. The unit surface removal rate values in this work compared favourably with literature data for EMB degrading other xenobiotics (for instance, phenol, retention time 353 min, removal rate 94.1 mg/h.m2). Studies are underway to determine 2,4-D removals at longer retention times. Overall, the EMB seems to be an effective configuration for removing 2,4-D while at the same time avoiding the active biomass exposure to the low pH and high salinity concentration of the influent.
Coupling ultrafiltration and adsorption onto activated carbon cloth: application to the treatment of highly coloured wastewaters
Authors: Pignon H. , Brasquet C. , Le Cloirec P.
Published: May 2018

The aim of this work is to evaluate the efficiency of Activated Carbon Cloths (ACCs) as a refining treatment of membrane filtration in the case of effluent streams containing both dyes and suspended solids (SS) or colloids responsible for turbidity. It is divided into two parts. First, dye adsorption experiments are carried out. Kinetics and isotherms enable us to show the feasibility of the adsorption and to study the influence of different operating conditions. The results demonstrate that adsorption is enhanced under acidic conditions, the adsorption capacity being increased by 40% in some cases. Moreover, microscopic characteristics of ACCs have a great influence on the adsorption process: there is a relationship between the adsorbent porosity and the adsorbate molecular weight, the mesoporous adsorbent being more efficious to remove the larger molecular weight dyes. In the case of low molecular weight compounds, the adsorbent with the higher specific surface area provides the greater adsorption capacity. Molecular connectivity indexes were used to confirm the correlation of the molecular structure of the adsorbates with their adsorbability. The second part consists of an estimation of the efficiency of the coupling of ultrafiltration and adsorption onto ACC. Tests performed on a laboratory-scale coupling show that a molecular weight cut-off of 3,000 D gives rise to a 98% removal of turbidity whereas dyes are not much retained. Furthermore, ultrafiltration is useful in improving the adsorption capacities of ACC in a continuous flow reactor (up to 50%).
Methanogenic biodegradation of aromatic amines
Authors: Kalyuzhnyi S. , Sklyar V. , Mosolova T. , Kucherenko I. , Russkova J.a. , Degtyaryova N.
Published: May 2018

Batch methanogenic toxicity and biodegradability of 2-, 3- and 4-aminobenzoic acids (ABA) as well as 4- and 5-aminosalicylic acids (ASA) have been studied in the presence of two mesophilic (Shell and cattle) and one thermophilic sludges. The aminoaromatics tested practically did not inhibit methanogenesis up to concentrations of 3–7 g/l; moreover, some of them (2-ABA, 4-ABA and 5-ASA) even exert a stimulating effect on aceticlastic activity of the sludges. Concerning biodegradability, 5-ASA was completely mineralised by all the sludges tested; however, 4-ASA was not degraded at all by any of the sludges. Both mesophilic sludges were able to perform a complete mineralization of 2-ABA but this was not a case for the thermophilic sludge. 3-ABA was not biodegraded only in the presence of the Shell sludge. On the contrary, 4-ABA was quantitatively mineralised only by the Shell sludge. All the adapted sludges were able to mineralise the corresponding aminoaromatics in N-deprived media. Cross-acclimatisationtrials showed that 2-ABA-, 5-ASA- and salicylic acid adapted sludges were unable to degrade any other aminoaromatics tested that manifest about a different nature of key bacteria responsible for primary decomposition of these substrates. The main possibility of continuous mineralization of 2-ABA as a unique source of carbon and nitrogen has been demonstrated using mesophilic UASB reactor inoculated by adapted sludge.
Endogenous respiration rate in vapour phase biological reactors (VPBRs) during volatile organic compound (VOC) degradation
Authors: Villaverde S. , Fdz-Polanco F. , García Encina P.A.
Published: May 2018

Endogenous respiration rates within Pseudomonas putida biofilms growing on toluene and ethanol as sole external carbon source were evaluated using oxygen microelectrodes in a Flat Plate Vapour Phase Biological Reactor (FPVPBR). The endogenous respiration was experimentally evaluated in Pseudomonas putida 54G biofilm cultures growing on toluene and ethanol, by measuring the flux of oxygen through the liquid-biofilm interface in absence of any external carbon source. Two fluorescent probes, 2,4-diamidino-2-phenylindole (DAPI) and 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) were used to evaluate the number of total and respiring cells within the biofilm, respectively. Biofilm samples were also analysed for viable and VOC-culturable cells by spread plating on non-selective and selective media, respectively.

Results suggest that endogenous respiration rate may contribute significantly to the oxygen requirements of the overall process and, consequently, affect the performance of the VPBR degrading VOCs. In the time the biofilm growing process at expenses of VOCs may deviate towards serious cryptic growth and endogenous metabolism. The endogenous respiration within the biofilm is a function of the VOC concentration and in last term of the injury phenomena that may act as regulatory mechanism of the biofilm thickness and density, which might justify the absence of plugging phenomena in VPBR. As the VOC concentration increases, the injury increases, meaning increasing intracellular material leakage and injured cell death resulting in lysis products. These observations can justify the unusually long operation periods characterizing VOC vapours biofiltration units.
Vitellogenin as a biomarker for environmental estrogens
Authors: Jones P. D. , De Coen W. M. , Tremblay L. , Giesy J. P.
Published: May 2018

Much recent interest has focused on “xenoestrogens” in the environment. The potential for these chemicals to disrupt hormonal function in wildlife has led to the development of techniques to monitor the effects of discharges of these compounds particularly in aquatic environments. Increases in the concentration of the egg yolk precursor protein, vitellogenin (Vtg), in the plasma of fish and other vertebrates have been identified as a potentially useful biomarker of exposure to and the effects of chemicals with estrogen like properties. Here, we review the mechanisms underlying Vtg production, methods for the analysis of Vtg, and studies that have measured Vtg production in response to chemical or effluent exposure. These studies indicate that the production of Vtg may be a useful biomarker of exposure to estrogenic chemicals but that a greater understanding of the mechanism of action of these chemicals is required. In cyprinid fishes reproductive endpoints are more sensitive to exposureto xenoestrogens than Vtg induction. These observations indicate that Vtg induction is of more use as a biomarker of exposure to xenoestrogens rather than a predictor of adverse effects.
Genotoxicity analysis and hazardousness prioritization of a group of chemicals
Authors: Degirmenci E. , Ono Y. , Kawara O. , Utsumi H.
Published: May 2018

Genotoxic chemicals are increasingly being used in our daily life. 180-chemicals were screened to identify the priority of hazardousness from the point of view of their genotoxicity. Umu-test was used to evaluate the genotoxicity of these chemicals. Some chemicals exhibited high genotoxic response. A scoring algorithm was developed to evaluate the hazardousness level of these chemicals based on their genotoxicity level and four other characteristics: biodegradation probability, soil adsorption coefficient, (KOC), bioconcentration factor (BCF), Henry's Law constant (HLC). Then, these chemicals were sorted in a descending order of their hazardousness probability.
Flow, stock and destination of radioactive fallout Cs-137 in the global environment
Authors: Morisawa S. , Shimada Y. , Yoneda M.
Published: May 2018

Environmental fate of radionuclide caesium-137 (Cs-137), which was released for more than 30 years since 1945 to the global environment by the atmospheric nuclear detonation tests, was analyzed from an aspect to determine the transport rate between environmental media, the accumulation and mass distribution in each media and the final destination. The mathematical model was developed and validated by comparing the model estimation with the monitoring data, and the final distribution of Cs-137 and its overall decreasing rate were evaluated together with the health risks to the reference Japanese.

The mass distribution simulation showed that the final destination of the fallout Cs-137 is the deeper land and the ocean bottom, and that the apparent decreasing rate of Cs-137 in the humans' living environment is larger than the physical half-life of Cs-137 due to the environmental acceleration of radionuclide transportation.
Characterization of heavy metals and polycyclic aromatic hydrocarbons in urban highway runoff
Authors: Shinya M. , Tsuchinaga T. , Kitano M. , Yamada Y. , Ishikawa M.
Published: May 2018

Urban highway runoff samples collected from four rainfall drains were analyzed for heavy metals and polycyclic aromatic hydrocarbons (PAHs). The concentrations of constituents varied widely during the history of each storm and appeared to be highest in the first runoff water. Results showed that iron and aluminum were the principal constituents of particulates. Cadmium, chromium, copper, manganese, lead and zinc were mainly particulate-bound while nickel was mainly in dissolved form. The higher molecular weight PAHs were more associated with suspended solids in the runoff. Predominant PAHs-phenanthrene, fluoranthene and pyrene-comprised about 50% of fifteen quantified PAHs constituents in each sample. In the events where peak flush occurred during the initial phase, more than half the total load flowed out during the initial phase of runoff flow. In this case, initial runoff water treatment was believed to be effective. In results from Ames assay, mutagenicity was appreciably associated with PAHs in the particulate fraction of runoff water. The dissolved fraction also showed positive mutagenic response by unknown soluble aromatic compounds.
Supercritical water oxidation of sludges contaminated with toxic organic chemicals
Authors: Crain N. , Shanableh A. , Gloyna E.
Published: May 2018

Supercritical water oxidation (SCWO) is a proven technology for the treatment of contaminated organic wastes. Bench and pilot-scale work completed at The University of Texas at Austin's SCWO Laboratory have proven the technology effective for treating a variety of sludge types, including sludge contaminated with hazardous compounds. The studies included pulp and paper mill sludges and sludges derived from the treatment of municipal and industrial wastewaters. The results presented in this paper confirmed that the removal of the organic component of sludge, including the trace toxic organic compounds, using SCWO exceeded 99.9%. For example, the results show that the destruction removal efficiencies (DRE's) of the PCBs reached 99.99% in the contaminated sludge. No dioxins or furans were detected in the gaseous effluent resulting from the treatment of the PCB-contaminated sludge. These results demonstrate the technical effectiveness of SCWO as a sludge remediation technology.
The fractionation/concentration of aquatic humic substances by the sequential membrane system and their characterization with mass spectrometry
Authors: Ikeda K. , Arimura R. , Echigo S. , Shimizu Y. , Minear R. A. , Matsui S.
Published: May 2018

The sequential membrane system and electrospray ionization mass spectrometry are investigated on their usefulness for characterizing aquatic humic substances. In this research, the Suwannee River Fulvic Acid (SRFA) was used for the investigation. For the mass spectrometry, the optimum analytical conditions were determined. Two indices (i.e., the total ion intensity and the averaged molecular weight) obtained from the spectrum were found relevant for evaluating the physical characteristics of aquatic humic substances. The repetitious peaks at a discrete of 14 Da in the lower m/z range of the acquired spectrum suggested that the SRFA has the –CH2– based structure in its lower molecular weight region. For the sequential membrane system, the optimum operating conditions were determined. The SRFA could be fractionated and concentrated by this system. The significant difference of the averaged molecular weight among the concentrated fractions from the different size membranes indicated thatthis system is useful for the fractionation and concentration of the aquatic humic substances.
Development of reverse osmosis membrane seawater desalination in Japan
Authors: Magara Y. , Kawasaki M. , Sekino M. , Yamamura H.
Published: May 2018

The seawater desalination facilities by reverse osmosis membranes in the world are reviewed. The largest seawater desalination facility using reverse osmosis started its operation at Chatan water purification plant in Okinawa prefectural water works. The high-efficiency seawater desalination technology which improves the recovery ratio of fresh water up to 60% developed by a manufacturing company of reverse osmosis membranes in Japan is explained. Finally the state of the art of desalination technology development using reverse osmosis membranes is discussed.
Anoxic ponds in the sugar cane industry: a case study from Colombia
Authors: Calero C.X. , Mara D.D. , Peña M.R.
Published: May 2018

Waste stabilisation ponds are a common technology used to treat sugar mill wastewaters in Colombia. Despite this there are problems related to biological process design and construction of these units. The situation with regards to operation and maintenance is far from satisfactory and also contributes to pond malfunctioning. In this sense, a pond system located at Providencia sugar mill on the southwest region of Colombia, South America was evaluated. The system comprises an anaerobic pond followed by a secondary anoxic pond. The whole system removes 73-82% of the BOD, with 53-70% occurring in the secondary anoxic pond, which is satisfactory despite the predominant conditions of organic overloading. However, TSS removal was low in comparison to BOD removal. The secondary anoxic pond proved to be an efficient treatment unit with the advantage of controlling odour release through photosynthetic bacterial activity. Land area requirements were less than those for green algal facultative ponds.
Coupled transport of cyanide ions through liquid membranes
Authors: Aydiner C. , Kobya M. , Koyuncu I.
Published: May 2018

In this study, the transport kinetics of coupled transport of cyanide ions through liquid membrane (trichloromethane) containing tetraoctylammonium chloride as a carrier was examined at different temperatures. The kinetics of cyanide transport could be analyzed in the formalism of two consecutive irreversible first order reactions. The influence of the temperature on the kinetic parameters (k1d, k2m, k2a, Rmmax, tmax, Jdmax, Jamax) has been established. For maximum membrane entrance and exit fluxes, Jdmax and Jamax, the activation energies were found from the slopes of the two linear relationships: 9.02 kcal/mol and 11.20 kcal/mol, respectively. The values of the found activation energy indicate that in the first step the transport process of cyanide ions through liquid membrane is difussional controlled, whereas in the second step it is most probably controlled by species diffusion and the rate of the reversible chemical reaction.