AbstractThe study on distribution of oxygen transfer rate for a stirred bioreactor and simulated broths was carried out for four positions inside the broth and indicated the significant variation of kla on the bioreactor height. For all considered positions, kla initially increased to a maximum value with mixing intensification, decreasing then, as the result of the modification of mixing mechanism in presence of air bubbles. The increase of broth viscosity led to the significantly reducing of o...
Autori: Adina Segneanu, Anca-Irina Galaction, Dan Caşcaval, Radu Z. Tudose
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=25270

AbstractThe study on the distribution of oxygen transfer rate in a stirred bioreactor for Propionibacterium shermanii broths underlined the major influence of the presence and concentration of biomass on the interphasic transfer of oxygen. Owing to the bubbles surface blockage by the bacterial cells, the accumulation of biomass from 30.5 to 120.5 g/l d.w. led to the decreasing of kla for about 1.3- 2.4 times. Compared with the simulated broths without biomass having similar apparent viscosity, t...
Autori: Adina Segneanu, Anca-Irina Galaction, Dan Caşcaval
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=25364

Abstract Unlike the P. shermanii and S. cerevisiae cultures, the study on the distribution of oxygen transfer in stirred bioreactor for P. chrysogenum free mycelia broths indicated that this process is controlled mainly by the high apparent viscosity of broths, and less by the presence of fungus biomass. For this reason, the influence of fungus accumulation on the reduction of kla is attenuated compared with that obtained for bacterial or yeasts broths. The lower influence of fungus biomass i...
Autori: Anca-Irina Galaction, Dan Caşcaval, Marius Turnea, Stefanica Camarut
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=25606

? SUSTAINABLE CONCRETE HARDENING PROCESSES IN NORMAL CLIMATIC AND THERMAL TREATMENT CONDITIONS ? THE ENVIRONMENTAL DIMENSION ? AN INTERDISCIPLINARY RESEARCH AREA ? MENU PLANNING STRATEGY BASED ON ECOLOGICAL FOOTPRINT ? EVALUATING ENVIRONMENTAL IMPACT OF NIGERIAN COMPOSTED WASTES USING LABORATORY EXTRACTION TEST ? IN SITU RADIOFREQUENCY FIELD LEVEL ASSESSMENT IN TWO URBAN AREAS IN ROMANIA: OPEN QUESTIONS TO ELECTROMAGNETIC POLLUTION ? INNOVATIVE SOLUTION FOR WARNING ON HI...
Autori:
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=25657

? POLLUTION PREVENTION, A KEY TO ECONOMIC AND ENVIRONMENTAL SUSTAINABILITY ? A COMPARISON BETWEEN DIFFERENT SCENARIOS OF ROMANIAN MUNICIPAL SOLID WASTE TREATMENT BEFORE LANDFILLING ? A STUDY ON ENERGY CONSUMPTION IN ROMANIA ? ENVIRONMENTAL INFLUENCES ON STRESSED METALLIC SURFACES ? ASPECTS OF HYDRODYNAMICS AND MASS TRANSFER IN DIFFUSED AERATION SYSTEMS ? THE STATUS OF SOME SELECTED HEAVY METALS IN ROADSIDE SOILS OF BURSA PROVINCE, TURKEY ? PREPARATION AND CHARACTERI...
Autori:
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=25656

Abstract:One of the most complex aspects of water accounting is the assessment of point and diffuse source pollution. At present, thebuilding sector in European countries is responsible for 40% of the total energy consumption. To reduce the European Uniondependency on energy import, the strategy undertaken in Lisbon is to reduce as much as possible the energy consumption ofbuildings and to increase the share of renewable energy sources. As an average, house heating represents about 75% from the ...
Autori: Ferenc Kalmár, Tünde Kalmár
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=25750

Abstract Effects of the aeration rate on nutrient removal from synthetic domestic wastewater using an intermittently aerated sequencing batch reactor (IASBR) were studied at ambient temperature. Two aeration rates, 0.8 and 1 L air/min, were studied. At the aeration-rate of 0.8 L air/min, removals of COD, NH4+-N, total nitrogen (TN) and PO43--P were 84%, 96%, 75% and 99%, respectively. At the aeration rate of 1 L air/min, removals of COD, NH4+-N, TN and PO43--P were 90%, 99%, 70% and 66%, re...
Autori: Liam G. Henry, Liwen Xiao, Xinmin Zhan
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=25941

AbstractA new approach to environmental protection management is the aerobic microbial digestion of food industry wastewaters byusing those waters as substrate, while the pollutants contained work also as oxygen-vectors. In biotechnology, oxygen masstransfer is a key parameter involved in the design and operation of mixing–sparging bioreactors and it can be analyzed by meansof the oxygen mass transfer coefficient (kLa). The influence of a second liquid phase with higher oxygen affinity (in this ...
Autori: Elena Folescu
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=26097

AbstractThe reuse of a wastewater treatment system was investigated using intermittent media infiltration (IMI) to evaluate the fecalcoliform (FC) removal efficiency with natural zeolite containing clinoptilolite from the state of San Luis Potosí, Mexico and itszinc-modified form (Zeo-Zn). The municipal wastewater, which was from Saltillo, Coahuila, Mexico, was treated for FC analysisfor four months. The physicochemical properties of zeolite were analyzed, and their behavior as filter media for ...
Autori: Sasirot Khamkure
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=26212

AbstractLow water quality due to high levels of ammonia, chemical oxygen demand (COD), abnormal pH, and undesirable water color isprevalent in many prawn ponds in Malaysia. A composite medium used in the treatment of prawn pond effluent was examinedfor the reduction of undesirable parameters. The composite medium is a mixture of limestone, activated carbon, zeolite, and ricehusk. Experiments were conducted under three different conditions, i.e., sole aeration, adsorption, and adsorption with pre...
Autori:
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=26219

AbstractCd (II) removal efficiency of free and immobilized fungal consortia of 48-h-old Mucor sp. HI33 + 72-h-old Gliocladium virideAI003 + 72-h-old Aspergillus niger AH09 from aqueous solutions were tested under different aeration systems. Cd (II) removalby free cells under air bubble system aeration was higher (99.91%) than under shaker system aeration. Cd (II) removal byimmobilized fungal consortia was higher (83.18 %) under shaker system aeration and lower in air bubble system aerationrespec...
Autori: Arifa Tahir
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=26232

AbstractThe aim of this study is to evaluate the treatment performance of mono azo dye Methyl Orange (MO)-containing wastewater byrecirculated up-flow constructed wetland (UFCW) with and without supplementary aeration. The successive anaerobic andaerobic treatment of the UFCW reactors could effectively remove color, organic matters and intermediate aromatic aminessimultaneously in a single reactor. With influent 50 mg/L of MO, the removal efficiencies of COD and MO were 91 and 75 %,respectively,...
Autori: Soon-An Ong
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=26254

AbstractThe aim of this paper was to study the performance of a single-stage rotating biological contactor with supplemental aeration interms of removal efficiency of organic and nitrogen content. Research was based on fifteen samples collected during the fouryear period. The wastewater was low strength with maximal measured concentration of 362 mg COD/l, 100 mg NH4/l, and 324mg TSS/L. The maximal measured removal efficiency of COD (chemical oxygen demand) and TSS (total suspend solids) were71% ...
Autori: Dragan Cvetkovic, Dusan Gordic, Milorad Bojić, Srdjan Stosic, Vanja Susterstic
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=26322

AbstractThe explosion phenomenon is an extremely complex physical-chemical process, which leads to the physical change of objectsand objectives encountered on the propagation path, as wells as the chemical modification of the underground atmosphere fromthe area of influence. During the underground propagation of the explosion, the most affected objectives are the following:ventilation constructions, regulation and insulation doors and the insulation dams. Dynamic pressure waves generated by thee...
Autori: Doru Cioclea
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=26401

AbstractA lab-scale packed-bed biofilm channel reactor that operates as a plug-flow system equipped with top aeration modules wasconstructed and evaluated. To assess the reactor performance a microbial community able to degrade linuron was used. Changingthe fluid flow rates and the linuron concentrations in the inflowing medium the volumetric loading rates of linuron (BV,L) weregradually increased from 0.29 to 14.93 mg/Lh. During the operation of the reactor, an airflow rate of 0.15 ą 0.05 L/min...
Autori: Erick Marrón-Montiel
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=26465

AbstractThe incorporation of phosphorus (P) into sediments and the changes in its bioavailability under intermittent P input and sedimentresuspension conditions were investigated via laboratory experiments. The sediments were disturbed daily for 10 min and thenallowed to settle for 1430 min after each disturbance to simulate the intermittent sediment resuspension conditions. The removalof soluble reactive P from the overlying water under sediment resuspension was greater than that under static c...
Autori: Li Dapeng
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=26567

Abstract The oxygen transfer into the fermentation broths could be improved in presence of oxygen-vectors, without intensification of mixing or aeration. The experimental results for simulated, P. shermanii and S. cerevisiae broths indicated the significant increase of kLa, by adding n-dodecane, but the magnitude of this effect depends especially on the cells affinity for hydrocarbon droplets. Therefore, due to the higher affinity of yeasts cells for hydrocarbon droplets during their entire ...
Autori: Anca Irina Galaction
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=26657

Abstract This study focused on the use of jet aeration to treat printing and dyeing wastewater. The related environmental factors influencing the dynamical efficiency of a jet aerator were investigated. Results showed that an ideal linear relation existed between dynamical efficiency and working pressure (R2 > 0.98), with dynamical efficiency decreasing gradually as the working pressure increased. When the gas–liquid ratio was approximately 0.6:1 to 1.4:1, more bubbles were formed b...
Autori: Chunsheng Le
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=26664

Abstract Superintensive growth of fish in a controlled environment involves taking a series of measures to ensure the oxygen necessary to provide optimal living conditions for stocks. Considering the fact that oxygen has a relatively low solubility in water, the photosynthesis in basins does not occur and the rate of incoming water may be low, it is imperative to supplement the water with oxygen. The paper presents theoretical researches on mathematical modelling and numerical simulation of ...
Autori: Vasilica Ştefan
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=26871

Water scarcity, the degradation of freshwater resources, and wastewater pollution are reaching crisis levels, especially in arid regions of the world. The reuse of wastewater was investigated by using intermittent media infiltration (IMI) to evaluate fecal coliform (FC) removal efficiency. Twelve IMI columns were packed with soil and natural filtering materials (sand, zeolite, vermicompost and charcoal) at percentages of 25, 50 and 75. The municipal wastewater was treated for the FC analysis ...
Autori: Sasirot Khamkure
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=26935

Sequencing Batch Biofilter Granular Reactors (SBBGRs) represent an innovative technology; coupling granular and attached biomass and operating in a batch mode. These systems allow good removal rates with low sludge production and space requirement. A particular application, consisting of an aeration unit and an upflow SBBGR in series, has been tested at pilot scale. The pilot system was installed at a conventional activated sludge plant and fed with average-strength urban wastewater after pre...
Autori: Paolo Cirello
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=27123

The direct measurement of the nutrients largely contributes to understand how the quality of the information, coming from the instruments, may improve the performances of the plants. The advanced knowledge acquired on the meaning of the signals gives new possibilities to control the biological processes and estimate the operational state of the plant, improving the quality of the effluent and keeping the operational costs as low as possible. Such information, furthermore, can be used to under...
Autori: Carmine Fiorentino
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=27127

This study examines the impact of the chemical oxygen demand to nitrogen ratio (COD:N) on nitrous oxide (N2O) emissions during N removal via a nitrite (NO2−) pathway for synthetic livestock wastewater treatment. Based on typical cycle operations, 1.07 ± 0.07% of the incoming N load was emitted as N2O at a COD:N ratio of 3:1. This was higher than the 0.83 ± 0.08% emitted at a COD:N ratio of 6:1. The low COD:N ratio in the synthetic livestock wastewater may thus cause increa...
Autori: Qiang Kong
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=27157

In this work, the effect of cyclic anaerobic/aerobic conditions on the biodegradative capability of the mixed microbial culture for the azo dye Acid Red 18 was investigated in the sequencing batch reactors. For this purpose, five anaerobic/aerobic sequencing batch reactors were operated under the same operation conditions at different anaerobic/aerobic reaction times. The whole reaction time was 22-h with anaerobic/aerobic periods of 6/16, 10/12, 14/8, 18/4 and 22/0 (h/h) in An/ASBR1 to 5, respe...
Autori: Mohammad Hakimelahi
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=27191

After the entry into force of Landfill Directive 1999/31/EC the member states of European Union (EU) turned towards other technologies for waste treatment and management, such as mechanical-biological treatment of waste (MBT) in order to meet the obligations related to the reduction of the amount of landfilled biodegradable waste. This paper presents an analysis of the waste management in Poland in terms of the current regulations and requirements of the EU and achievement of the mechanical - bi...
Autori: Monika Suchowska-Kisielewicz
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=27266

The level of dissolved oxygen (DO) in the water downstream hydro power plants is an essential parameter which allows preservation and development of the aquatic habitat. The objective of this paper is to identify a new technical solution that contributes to the increase of DO level in the water passing through the turbine. The current technical solutions improve the DO level but affect the hydraulic efficiency of the turbine. There is no general technical solution for aeration of water used by h...
Autori: Florentina Bunea
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=27296

The necessary oxygen concentration for the biological process depends on the organic matter present in wastewater characterized by organic matter reaction rate with oxygen, k. This article highlights the impact of the reaction coefficient on oxygen dispersion in water. The first stage of the research led to the determination of the ratio between the coefficient of reaction and the coefficient of dispersion on the vertical of the tank as k/εz ϵ [0.066 - 0.79]. Starting from this rat...
Autori: Corina Boncescu
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=27298

Arsenic removal from groundwater as drinking water source was investigated using electrocoagulation (EC) process with horizontal anodes of iron plate under galvanostatic regime. The current density of 5 A·m-2 was determined as the optimum operating conditions at the electrolysis time of maximum 25 minutes and pH ranged between 6.5 to 8.5, by which the arsenic concentration was reduced below 10 μg·L-1. The aspects related to the arsenic removal mechanism were discussed by Zeta...
Autori: Aniela Pop
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=27327

Continuously increasing energy prices, as well as the increasing number of legal stipulations, bring to the attention of scientists the necessity of finding solutions for energy saving by using different heat sources. According to the EU Action Plan, the highest potential of energy savings (27-30% until 2020) will be applied to the existing buildings. Under the circumstances of environmental issues, research on the use of secondary energy resources is of great interest, being a concern in the...
Autori: Timea Gabor
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=27395

This paper presents an experimental study regarding the influence of fine bubble generators (FBG) nozzles on the oxygen transfer rate from air to water, in case of pneumatic aeration processes of stationary (still) waters. This experimental study was conducted after three types of fine bubbles generators were previously computed, designed and constructed to satisfy the conditions imposed in order to provide valid experimental results. The three constructive versions were tested under similar op...
Autori: Ionela Mihaela Căluşaru
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=27579

The mineralization of azo dyes could be realized through solar photocatalytic degradation that is a green method where non-harmful end products are produced. The aim of this study was to investigate the mineralization of Orange G (OG) and New Coccine (NC) using ZnO as catalyst. The degradation of the azo dyes was conducted at different experimental conditions, and parameters such as effect of sunlight to the degradation rate, initial azo dye concentration, amounts of catalyst dosage, pH and effe...
Autori: Wan Fadhilah Khalik
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=27643

The performance of cathode affects the overall performance of a microbial fuel cell (MFC), and cathode configuration affects the fabrication cost of this bioelectrochemical system in a large way. Various modifications in cathode structures have been observed in MFCs. Among them air-cathode MFCs are considered to be the most efficient and sustainable option due to elimination of aeration, as required in aqueous cathodes which consumes energy and increases operating cost of MFCs. An air cathode us...
Autori: Pritha Chatterjee
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=27680

The aim of this paper was to investigate and understand the relationship between several physical and chemical parameters such as temperature, chemical oxygen demand (COD), and biochemical oxygen demand (BOD) on the one hand and dynamics of bacterial populations involved in the breakdown (hydrolysis) of macromolecular organic matter, on the other. The study was carried out during July-November 2009 at Cernavoda Wastewater Treatment Plant and included quantitative estimation of proteolytic, amylo...
Autori: Constantin Ioan
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=27872

High sulfide inhibited the activities of sulfate-reducing bacteria (SRB) and methane-producing bacteria (MPB). In addition, a large number of domestic sewages should be treated in China. Thus, it is the first time that domestic sewage was collected to dilute high-sulfate wastewater in this study to achieve simultaneous treatment of sulfate wastewater and domestic sewage in the anaerobic baffled reactor (ABR). The results showed that there were obvious separation of sulfate reduction phase and me...
Autori: Peng Wu
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=27840

Human activities have intensively relied on and utilized riparian areas that have led to their substantial degradation. This is the reason why easy-to-use, reliable, inexpensive monitoring tools that describe the ecosystem integrity of riparian areas need to be developed. Bio-indicators are such tools, with many recommending the use of ground-dwelling insects. This study evaluates the use of diversity indices on ground-dwelling insects for three representative riparian habitat types of Greece. T...
Autori: George Nick Zaimes
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=28060

The aim of this research was to improve the removal of organic matter and nutrients from wastewater from pig farms in a combined batch reactor performed as anaerobic-aerobic sequential. For this purpose, it was suggested to include recirculation cycles of wastewater in a sequentially pulsed manner in the anaerobic treatment followed by intermittent aeration in the aerobic-anoxic treatment. This novelty implemented in both sequential reactors was studied under pilot scale conditions. The process ...
Autori: Jorge Alonso Cortes-Esquivel
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=28101

The present study represents an extension of ergosterol production by Saccharomyces cerevisiae fermentation processes using oxygen-vector by establishing the influence of the analyzed main factors, such as aeration efficiency and hydrocarbon concentration. The study has been developed for batch and fed-batch fermentation systems and has been focused on the variation of ergosterol content inside the yeast cells during the fermentation cycle in correlation with hydrocarbon volumetric fraction, COV...
Autori: Corina Ciobanu
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=28130

Growth rate and biomass yield in the case of Arthrospira platensis depend on nutrient availability, temperature and light, which can determine changes in the metabolism and therefore in the biomass composition. The aim of this study is to evaluate the behavior of A. platensis during the growing time in several liquid culture media and their influence on the yield of biomass production. The following culture media have been investigated in this sense: ARS, Zarrouk (Z), modified Zarrouk (MZ), eco...
Autori: Mariana Diaconu
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=28163

This study investigates the capability of furnace bottom ash (FBA) as a filter media for phosphorus removal from wastewater effluents. Lab-scale studies were conducted, in which a mass of FBA was brought into contact with the phosphate solution (a predominant form of phosphorus in wastewater) in batch experiments and lab-scale filter. Intraparticle Diffusion Model (IPD) was applied and revealed that the mechanism of phosphate adsorption onto FBA consist of three phases; film phase occurred in...
Autori: Ali Alzeyadi
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=28191

Techniques such as composting, a controlled process of decomposition of organic materials, have become fundamental to minimize the problems associated with the organic fraction of urban solid waste, as the potential to cause damage to public health, the environment and, consequently, to economic and administrative aspects can be related to this kind of waste. Microbial activity is also highlighted as a relevant factor since the microorganisms are fundamental in the degradation of organic matter...
Autori: Priscila da Costa
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=28222