Evaluation of the Bioelectrochemical Approach and Different Electron Donors for Biological Trichloroethylene Reductive Dichlorination

Trichloroethylene (TCE) and more in general chlorinated aliphatic hydrocarbons (CAHs) can be removed from a contaminated matrix thanks to microorganisms able to perform the reductive dechlorination reaction (RD). Due to the lack of electron donors in the contaminated matrix, CAHs’ reductive dechlorination can be stimulated by fermentable organic substrates, which slowly release molecular hydrogen through their fermentation. In this paper, three different electron donors constituted by lactate, hydrogen, and a biocathode of a bioelectrochemical cell have been studied in TCE dechlorination batch experiments. The batch reactors evaluated in terms of reductive dechlorination rate and utilization efficiency of the electron donor reported that the bio-electrochemical system (BES) showed a lower RD rate with respect of lactate reactor (51 ± 9 µeq/d compared to 98 ± 4 µeq/d), while the direct utilization of molecular hydrogen gave a significantly lower RD rate (19 ± 8 µeq/d), due to hydrogen low solubility in liquid media. The study also gives a comparative evaluation of the different electron donors showing the capability of the bioelectrochemical system to reach comparable efficiencies with a fermentable substrate without the use of other chemicals, 10.7 ± 3.3% for BES with respect of 3.5 ± 0.2% for the lactate-fed batch reactor. This study shows the BES capability of being an alternative at classic remediation approaches.

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Performance of Denitrifying Phosphorus Removal by Aerobic Granular Sludge at Low Temperature

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.71-78.2966 ◽

2011 ◽

Vol 71-78 ◽

pp. 2966-2969 ◽

Cited By ~ 1

Author(s):

Rui Ling Bao ◽

Xiao Ju Yan ◽

Shui Li Yu

Keyword(s):

Low Temperature ◽

Phosphorus Removal ◽

Film Growth ◽

Batch Reactor ◽

Granular Sludge ◽

Utilization Efficiency ◽

Aerobic Granular Sludge ◽

Organic Substrates ◽

Denitrifying Phosphorus Removal ◽

Different Types

To deeply understand the performance of denitrifying phosphorus removal by aerobic granular sludge at low temperature, an aerobic granular sludge sequencing batch reactor had been operated at 10±1°C. The results showed that the PHAs components synthesized by phosphorus accumulating organisms (PAOs) in granule sludge were affected by different types of carbon source in anaerobic period, and the release and uptake of phosphate were also influenced. It was indicated that the increased ratio of PHV to PHAs led to the increase of the utilization efficiency of nitrate by denitrification PAOs. When initial COD concentration in anaerobic period was lower than 300mg/L, it can effectively keep organic substrates from flowing into the following anoxic period which influenced the efficiency of denitrifying phosphorus removal. Inhibition of nitrite to denitrifying phosphorus removal was decreased due to biology film growth manner of aerobic granular sludge. The inhibitory concentration of nitrite to denitrifying PAOs was 60 mg/L.

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Dynamics of phosphorus and organic substrates in anaerobic and aerobic phases of a sequencing batch reactor

Water Science & Technology ◽

10.2166/wst.1994.0274 ◽

1994 ◽

Vol 30 (6) ◽

pp. 237-246 ◽

Cited By ~ 21

Author(s):

A. Carucci ◽

M. Majone ◽

R. Ramadori ◽

S. Rossetti

Keyword(s):

Sequencing Batch Reactor ◽

Municipal Wastewater ◽

Batch Reactor ◽

General Assumption ◽

Organic Substrate ◽

Operating Conditions ◽

Phosphate Removal ◽

Substrate Uptake ◽

Organic Substrates ◽

Polyphosphate Metabolism

This paper describes a lab-scale experimentation carried out to study enhanced biological phosphate removal (EBPR) in a sequencing batch reactor (SBR). The synthetic feed used was based on peptone and glucose as organic substrate to simulate the readily biodegradable fraction of a municipal wastewater (Wentzel et al., 1991). The experimental work was divided into two runs, each characterized by different operating conditions. The phosphorus removal efficiency was considerably higher in the absence of competition for organic substrate between P-accumulating and denitrifying bacteria. The activated sludge consisted mainly of peculiar microorganisms recently described by Cech and Hartman (1990) and called “G bacteria”. The results obtained seem to be inconsistent with the general assumption that the G bacteria are characterized by anaerobic substrate uptake not connected with any polyphosphate metabolism. Supplementary anaerobic batch tests utilizing glucose, peptone and acetate as organic substrates show that the role of acetate in the biochemical mechanisms promoting EBPR may not be so essential as it has been assumed till now.

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A simulation apparatus for the experimental study of batch reactor control methods

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19861259 ◽

1986 ◽

Vol 51 (6) ◽

pp. 1259-1267

Author(s):

Josef Horák ◽

Petr Beránek

Keyword(s):

Experimental Study ◽

Closed Loop ◽

Dynamic Properties ◽

Batch Reactor ◽

Exothermic Reaction ◽

Electric Heating ◽

Batch Reactors ◽

Exchange Area ◽

The Stability ◽

Methods Of Control

A simulation apparatus for the experimental study of the methods of control of batch reactors is devised. In this apparatus, the production of heat by an exothermic reaction is replaced by electric heating controlled by a computer in a closed loop; the reactor is cooled with an external cooler whose dynamic properties can be varied while keeping the heat exchange area constant. The effect of the cooler geometry on its dynamic properties is investigated and the effect of the cooler inertia on the stability and safety of the on-off temperature control in the unstable pseudostationary state is examined.

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A Microcosm Treatability Study for Evaluating Wood Mulch-Based Amendments as Electron Donors for Trichloroethene (TCE) Reductive Dechlorination

Water ◽

10.3390/w13141949 ◽

2021 ◽

Vol 13 (14) ◽

pp. 1949

Author(s):

Edoardo Masut ◽

Alessandro Battaglia ◽

Luca Ferioli ◽

Anna Legnani ◽

Carolina Cruz Viggi ◽

...

Keyword(s):

Electron Donor ◽

Environmental Sustainability ◽

Reductive Dechlorination ◽

Environmental Remediation ◽

Low Cost ◽

Chlorinated Solvents ◽

Electron Donors ◽

Chlorinated Ethenes ◽

Dehalococcoides Mccartyi ◽

Wood Mulch

In this study, wood mulch-based amendments were tested in a bench-scale microcosm experiment in order to assess the treatability of saturated soils and groundwater from an industrial site contaminated by chlorinated ethenes. Wood mulch was tested alone as the only electron donor in order to assess its potential for stimulating the biological reductive dechlorination. It was also tested in combination with millimetric iron filings in order to assess the ability of the additive to accelerate/improve the bioremediation process. The efficacy of the selected amendments was compared with that of unamended control microcosms. The results demonstrated that wood mulch is an effective natural and low-cost electron donor to stimulate the complete reductive dechlorination of chlorinated solvents to ethene. Being a side-product of the wood industry, mulch can be used in environmental remediation, an approach which perfectly fits the principles of circular economy and addresses the compelling needs of a sustainable and low environmental impact remediation. The efficacy of mulch was further improved by the co-presence of iron filings, which accelerated the conversion of vinyl chloride into the ethene by increasing the H2 availability rather than by catalyzing the direct abiotic dechlorination of contaminants. Chemical analyses were corroborated by biomolecular assays, which confirmed the stimulatory effect of the selected amendments on the abundance of Dehalococcoides mccartyi and related reductive dehalogenase genes. Overall, this paper further highlights the application potential and environmental sustainability of wood mulch-based amendments as low-cost electron donors for the biological treatment of chlorinated ethenes.

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Minimization of N2O Emission through Intermittent Aeration in a Sequencing Batch Reactor (SBR): Main Behavior and Mechanism

Water ◽

10.3390/w13020210 ◽

2021 ◽

Vol 13 (2) ◽

pp. 210

Author(s):

Tang Liu ◽

Shufeng Liu ◽

Shishi He ◽

Zhichao Tian ◽

Maosheng Zheng

Keyword(s):

Wastewater Treatment ◽

Wastewater Treatment Plants ◽

Batch Reactor ◽

Quantitative Polymerase Chain Reaction ◽

N2o Emission ◽

Ammonia Oxidizer ◽

Batch Reactors ◽

Intermittent Aeration ◽

Major Pathway ◽

Nitrifier Denitrification

To explore the main behavior and mechanism of minimizing nitrous oxide (N2O) emission through intermittent aeration during wastewater treatment, two lab-scale sequencing batch reactors operated at intermittently aerated mode (SBR1), and continuously aerated mode (SBR2) were established. Compared with SBR2, the intermittently aerated SBR1 reached not only a higher total nitrogen removal efficiency (averaged 93.5%) but also a lower N2O-emission factor (0.01–0.53% of influent ammonia), in which short-cut nitrification and denitrification were promoted. Moreover, less accumulation and consumption of polyhydroxyalkanoates, a potential endogenous carbon source promoting N2O emission, were observed in SBR1. Batch experiments revealed that nitrifier denitrification was the major pathway generating N2O while heterotrophic denitrification played as a sink of N2O, and SBR1 embraced a larger N2O-mitigating capability. Finally, quantitative polymerase chain reaction results suggested that the abundant complete ammonia oxidizer (comammox) elevated in the intermittently aerated environment played a potential role in avoiding N2O generation during wastewater treatment. This work provides an in-depth insight into the utilization of proper management of intermittent aeration to control N2O emission from wastewater treatment plants.

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Stochastic modeling of microstructure of homopolymers and copolymers in batch reactor

Research Society and Development ◽

10.33448/rsd-v9i2.1930 ◽

2020 ◽

Vol 9 (2) ◽

pp. e04921930

Author(s):

Matheus Dias Carvalho ◽

Jorge David Alguiar Beliido ◽

Antonio Marcos de Oliveira Siqueira ◽

Júlio Cesar Costa Campos

Keyword(s):

Stochastic Modeling ◽

Chemical Reactions ◽

Batch Reactor ◽

Polymer Chains ◽

Stochastic Methods ◽

Batch Reactors ◽

Straight Chain ◽

Reaction Conditions ◽

C Language ◽

Methyl Styrene

Find the microstructure of the product generated in a reaction of polymerization is desirable from a material science standpoint, due to the association between the microstructure and the physical properties. For the science of this fact, this paper aims to use stochastic modeling to obtain the microstructure and key information from a set of polymer chains generated during a reaction. From this data, the present article contributes to the minimization of experimental expenses, besides the saving of time, since no experiments are necessary to discover the characteristics of the polymer obtained under certain reaction conditions. This information cannot be found by other usual methodologies for modeling chemical reactions, such as the deterministic form. Also, from a given desired structure, the initial concentration and temperature conditions for forming that product can be obtained. This study was conducted based on Monte Carlo stochastic methods, by which we seek to replicate the randomness present in chemical reactions. The algorithm created in C ++ language determines the variation of the number of molecules of each species with time, besides the chemical composition, the sequence of mere and size of the generated chains. This approach applies to straight-chain homopolymerizations and copolymerizations. In this paper, we studied the polymerization in styrene batch reactors to form polystyrene, in addition to the copolymerization of styrene with alpha-methyl styrene. These simulations were characterized by forming chains with small blocks of monomers.

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A Novel Approach of Bioesters Synthesis through Different Technologies by Highlighting the Lowest Energetic Consumption One

Polymers ◽

10.3390/polym13234190 ◽

2021 ◽

Vol 13 (23) ◽

pp. 4190

Author(s):

Simona Popa ◽

Andra Tamas ◽

Vasile Simulescu ◽

Dorin Jurcau ◽

Sorina Boran ◽

...

Keyword(s):

Fatty Acids ◽

Energy Consumption ◽

Bubble Column ◽

Batch Reactor ◽

Reaction Times ◽

Fatty Acid Esters ◽

Bubble Column Reactor ◽

Batch Reactors ◽

Novel Approach ◽

Microwave Reactors

Fatty acids esters have a wide application as bioplasticizers and biolubricants in different industries, obtained mainly in classic batch reactors, through an equilibrium complex reaction, that involves high temperatures, long reaction times, vigorously stirring, and much energy consumption. To overcome these shortcomings, we synthesized a series of fatty acid esters (soybean oil fatty acids being the acid components with various hydroxyl compounds) through novel low energy consumption technologies using a bubble column reactor, a microwave field reactor and for comparison meaning, a classic batch reactor. The obtained bioesters physicochemical properties were similar to one another, a good concordance among their rheological properties was obtained, but the energetic consumption is lower when using the bubble column or the microwave reactors instead of the classical batch reactor.

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Anaerobic Digestion Process for the Treatment of Sisdole Landfill Leachate in Nepal

Journal of Southwest Jiaotong University ◽

10.35741/issn.0258-2724.55.4.35 ◽

2020 ◽

Vol 55 (4) ◽

Author(s):

Bikash Adhikari ◽

Shilpa Koirala

Keyword(s):

Anaerobic Digestion ◽

Removal Efficiency ◽

Landfill Leachate ◽

Waste Treatment ◽

Batch Reactor ◽

Batch Reactors ◽

Leachate Treatment ◽

Anaerobic Digestion Process ◽

Digestion Process ◽

Solids Concentration

Along with the population, organic waste has been rising significantly in recent years. The resulting uncontrollable waste loads and conventional methods of waste treatment have begun to cause chaos at the landfill sites. This study evaluates the performance of an anaerobic digestion process using batch reactors for the treatment of landfill leachate collected from the Sisdole landfill site in Nuwakot, Nepal. A lab-scale anaerobic batch reactor was set up in Kathmandu University, Nepal. Using an anaerobic digestion process, COD values of the leachate decreased from 2230 mg/l to 1125 mg/l (removal efficiency of ~50%), whereas total solids concentration decreased from 1925 to 925 mg/L under a retention time of 10 days. In addition, Monod’s model was established to design an Anaerobic Sequential Batch Reactor to achieve better performance, resulting in 85% removal efficiency for the leachate treatment. Overall, this study analyzed the anaerobic digestion process on the landfill leachate of Sisdole, and modeled the process to identify the conditions required for increasing the efficiency of treatment of Sisdole landfill leachate.

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Performance Analysis of Three Controllers for the Polymerisation of Styrene in a Batch Reactor

Chemical Product and Process Modeling ◽

10.2202/1934-2659.1014 ◽

2007 ◽

Vol 2 (1) ◽

Cited By ~ 2

Author(s):

Emmanuel E Ekpo ◽

Iqbal M Mujtaba

Keyword(s):

Performance Analysis ◽

Batch Reactor ◽

Monomer Conversion ◽

Average Chain Length ◽

Generic Model ◽

Batch Reactors ◽

Dynamic Optimisation ◽

Model Control ◽

Simple Kinetic Model ◽

Generic Model Control

The performance analysis of three advanced non linear controllers is the main focus of this paper. All three controllers are applied for the control of a batch polymerisation reactor which is defined by a very simple kinetic model for the polymerisation of styrene. This simple set of equations describing the polymerisation process is first solved using the sequential strategy i.e. Control Vector Parameterisation (CVP) technique within gPROMS to find optimal initial initiator concentrations and the reactor temperature trajectory necessary to yield desired polymer molecular properties (defined here as fixed values of monomer conversion and number average chain length) in minimum time. The sequential solution strategy has had limited application in solving optimisation problems for polymerisation in batch reactors, most researchers instead employing the Pontryagin's Maximum Principle (PMP) to solve optimal control problems involving these systems.The temperature trajectory obtained from the dynamic optimisation is used as the setpoint to be tracked by the three controllers: Dual Mode control with PID, which is representative of industrial practice, Generic Model Control (GMC) with Neural Networks as online heat release estimator, and Direct Inverse Control (DIC). Published work on the last two controllers as applied to the control of a batch polymerisation reactor is absent from the literature.When the performances of the different controllers are evaluated, it is seen that the GMC-NN controller performs better than the other two for the system under consideration.

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