C. vulgaris

Resumo: O objetivo foi produzir Spirulina sp. (LEB 18) biomassa pela reutilização e tratamento de águas residuárias da aquicultura, determinando o melhor desempenho produtivo através de parâmetros cinéticos. Os cultivos foram realizados em fotobiorreatores (1L) com 100% de água residual de aquicultura suplementada com T-25, T-50, T-75. Não houve diferença significativa na concentração de biomassa nos tratamentos 50% (1,02 gL-1), 25% (1,10 gL-1) e controle (1,05 gL-1). Assim, o tratamento com 25% representa uma alternativa eficiente, barata e sustentável para o setor de aquicultura, reduzindo os impactos das descargas de efluentes, produzindo biomassa de baixo custo com características diferenciadas e alto valor agregado.

Recebido em 29/03/2019; aceito em 18/06/2019; publicado na web em 01/08/2019 BIORREMEDIATION OF INDUSTRIAL EFFLUENT USING MICROALGAE. National industrial effluent remediation strategies are largely outdated, which makes these processes costly and at the same time inefficient. Among the most worrying compounds are heavy metals, which have bioaccumulative and toxic characteristics to living beings. In addition to these, high nutrient loads constitute a huge environmental problem, since the devastation promoted by eutrophic niches is capable of disrupting complex food chains. This paper presents a bibliographical review of the current researches that are applying biomass from microalgae in effluent bioremediation, both domestic and industrial (mainly the latter, since its pollution potential is abruptly greater). Such strategy is interesting since the diversity of these microorganisms is abundant, propitiating the application of them in various conditions. Another point to be taken into consideration is the fact that many species of microalgae produce large amounts of lipids, many of which have potential application in the production of biodiesel.

RESUMO-Biomassas provenientes de diferentes fontes apresentam potencial para serem convertidas em produtos químicos e combustíveis gasosos para geração de energia. As algas têm o potencial de produzir consideravelmente maiores quantidades de biomassa e de lipídios por hectare do que qualquer tipo de biomassa terrestre, com a vantagem de poderem ser cultivadas em terras marginais, portanto não competem com a produção de alimentos ou outras culturas. No presente trabalho foi estudado o processo de gaseificação da microalga Chlorella vulgaris e a cinética de reação. Os experimentos foram realizados utilizando equipamento de análise termogravimétrica acoplado a um cromatógrafo gasoso. O efeito dos principais parâmetros tais como massa da amostra, temperatura de reação e vazão do gás de arraste (Argônio) foram avaliados. Os gases produzidos foram analisados por cromatografia gasosa, onde os principais produtos detectados durante a gaseificação foram H 2 , CO, CO 2 e CH 4 , indicando que reações de gás de água, de oxidação e de deslocamento de água, foram predominantes.

Est e projeto não seria possível sem a colaboração de vários parceiros ao longo desses oito anos de trabalho. Foram muitas parcerias e contribuições de professores, alunos e profissionais da área que agregaram conhecimento ao grupo do Laboratório de Processos Oxidativos Avançados (LabPOA). Aos órgãos fomentadores (CNPq, Funcap e Capes) das pesquisas que, mediante os projetos aprovados nos editais (CHAMADA MCTI/ CNPq/CT-BIOTEC N o 30/2013/ INOVAFIT 2015-PROPOSTA DE CHAMADA FUNCAP-FASE 1 EDITAL N o 14/2015/ EDITAL FUNCAP/FINEP-PAPPE INTEGRAÇÃO N o 02/2016/ PAPPE INTEGRAÇÃO FUNCAP/FINEP EDITAL N o 06/2013), possibilitaram o desenvolvimento das pesquisas e a elaboração desta obra.

têm o direito, perpétuo e sem limites geográficos, de arquivar e publicar esta dissertação através de exemplares impressos reproduzidos em papel ou de forma digital, ou por qualquer outro meio conhecido ou que venha a ser inventado, e de a divulgar através de repositórios científicos e de admitir a sua cópia e distribuição com objetivos educacionais ou de investigação, não comerciais, desde que seja dado crédito ao autor e editor. v vi Agradecimentos Gostaria de agradecer aos meus colegas que me acompanham desde o Instituto Superior de Agronomia e que tal como eu, ingressaram neste mestrado tornando o percurso académico mais leve e alegre. Agradecer também à turma espetacular de MEER que se formou no ano letivo 2017/2018, pela união e boa disposição sempre presente. Um especial agradecimento à Catarina Vidoeira, à Carina Graça, à Viviana Nobre e Maria Alonso que por além de serem minhas colegas, tornaram-se grandes amigas ao longo destes 6 anos juntas. Obrigada também por me terem apoiado ao longo desta jornada e me terem dado sempre uma palavra reconfortante e de motivação quando os dias pareciam mais desafiantes. Aos meus amigos de vida António Cerqueira e Beatriz Pereira por estarem comigo desde a infância, obrigada pelas viagens, pelos cafés, pelos passeios, pelas palhaçadas, pelas idas à praia e por todos os momentos que vivemos enquanto escuteiros. Apesar de não estarem perto de mim fisicamente, estão perto de mim no coração e à distância de um telefonema ou de uma mensagem. Queria agradecer à minha família, em especial à minha irmã, Rita, por me ouvir e me dar sempre bons conselhos. À Catarina Nobre, por me ter ajudado imenso nesta reta final, pela paciência, boa disposição, sabedoria que partilhou comigo e por ter estado sempre disponível para me ajudar em qualquer dúvida que tinha. À Catarina Viegas por ter partilhado os seus conhecimentos comigo. Aos colegas de laboratório, Iara, Lilianne, Ricardo obrigada pela companhia e pelas cantorias que passavam no rádio, que tornavam os nossos dias mais alegres e assim terem tornado o laboratório 365, o mais divertido de todos. À minha orientadora, Professora Doutora Margarida Gonçalves, agradecer a confiança e disponibilidade para me ajudar na realização desta Dissertação e por todo o conhecimento que me passou. Ao meu co-orientador, professor Pedro Pereira agradecer o apoio e disponibilidade ao longo da execução desta dissertação. Ao Professor Doutor Mário Ventim, coordenador de mestrado de MEER, pela presença e apoio ao longo do mestrado. vii Palavras-chave: Lixiviado de aterro, pré-tratamento, biorremediação, eletrocoagulação, C.vulgaris, C. protothecoides.

Bu çalışmada Chlorella vulgaris mikroalgi kullanılarak belirli çevrim hızlarına sahip dinamik sistem ile statik sistem arasındaki popülasyon, konsantrasyon ve pH değişimleri incelenmiştir. Statik ve dinamik sistemlerde 14 günlük kültür süresince mikroalgin üreme süreci gözlemlenmiştir. Dinamik sistemde 1,5/3/6 mL/dk olmak üzere üç farklı çevrim hızı ile çalışılmıştır. 3000 lux ışık şiddeti ve 25 ℃ sabit ortam sıcaklığında, 12 saatlik periyotlarla ölçülen absorbanslar ile konsantrasyon miktarları (g/L) hesaplanmıştır. Sedgwick-Rafter yöntemiyle yapılan hücre sayımları ile her ölçüm saatindeki canlı hücre popülasyonları hesaplanmıştır. Konsantrasyon ve popülasyon ile birlikte sistemlerin pH değişimleri de gözlemlenmiştir. Hücre konsantrasyonu arttıkça pH’nın da arttığı gözlemlenmiştir. Elde edilen verilere göre dinamik sistemde statik sisteme oranla daha yüksek konsantrasyon, hücre popülasyonu ve popülasyon artış hızı elde edilmiştir. Sisteme kazandırılan dolaşımla birlikte statik sisteme kıyasla biyokütle birikmesinde bir azalma görülmüştür. 1.5 mL/dk çevrim hızında statik sisteme oranla aynı kültür süresi içerisinde, daha yüksek popülasyon ve konsantrasyon elde edilmiştir. 3 mL/dk çevrim hızı ile yapılan kültür süresince statik sisteme ve 1.5 mL/dk çevrim hızına sahip sisteme göre daha da yüksek popülasyon ve konsantrasyon elde edilmiştir. En yüksek konsantrasyon (0,39 g/L), pH artış hızı ve canlı hücre popülasyonu (1,76 × 106) 6 mL/dk çevrim hızına sahip dinamik sistemde elde edilmiştir. Böylelikle C. vulgaris mikroalginin dinamik bir sistemde kültür edilmesiyle daha hızlı bir konsantrasyon artışı ve daha yüksek bir popülasyon sağlanmaktadır.

The hydrodynamics of airlift reactors with net draft tubes (ALR-NDTs) constructed with certain geometric specifications were characterized according to dependencies of the overall gas holdup, mixing time, liquid velocity, and volumetric gas-liquid mass transfer coefficient on the air flow rate (Q g). The mesh size and height-to-diameter ratio (H/D) of the net draft tube, and the downcomer-to-riser cross-sectional area ratio (A d /A r) were among the geometric characteristics used to compare the performances of bubble column and airlift reactors with the ALR-NDTs. Several empirical correlations were developed to describe the relationship between the hydrodynamic characteristics and the geometric details under certain values of Q g. The specific cell growth rate (m) was improved considerably in ALR-NDT-12 (H/D ¼ 10.7, A d /A r ¼ 1.3, and Q g ¼ 1 vvm) compared to free cells suspended in a flask experiment (0.070 vs. 0.465 h À1). The cells were performed efficiently and the time to reach the maximum production of the enzyme was notably decreased over that of the free cells in the flask studies (44 vs. 34 h for ALR-NDT-12).

There is an increasing need for the investigation of recovery techniques for valuable elements, especially for the growing waste streams. This study focuses on the biosorption of commonly found valuable elements in e-waste: Ag+ and Nd3+ from aqueous solutions by using living and dried forms of Chlorella vulgaris. Optimization of the processes was conducted by changing the process parameters. In addition, biosorption from multi-metal solution (with Ag+, Nd3+, Au3+) was also investigated. Maximum removals were found as 174.6 ± 4.83 mg/g for Ag+, 239.7 ± 3.39 mg/g for Nd3+ by dried algae, and 161.6 ± 18.2 mg/g for Ag+, 296.8 ± 30.54 mg/g for Nd3+ by living algae. Both processes were very fast, representing 60 and 5–10 min during which a significant amount of the biosorption was completed for dried and living algae, respectively. FTIR and SEM–EDS showed that the algae were able to sorb the elements. Pseudo-second-order kinetics fit better to all processes. Freundlich model suited to the dried algae process, while the linear model fit to living algae process. The biosorption efficiency of Ag+ and Nd3+ decreased when there were co-ions present in the solution. Biosorption of Au3+ was affected depending on the experimental conditions in the case of multi-metal solutions.

Airlift bioreactors are considered very efficient for aerobic cultivation of microorganisms. In particular, for the cultivation of filamentous fungi, where low shear rates may be required. In this context, the main aim of this study was to design an airlift bioreactor built with an external loop, adequate for biomass production of microbial organisms, including ectomycorrhizal fungi. A 5-L airlift bioreactor was constructed and experimental studies performed under an air-salt solution system (0.15 mol/L NaCl), in order to characterize the reactor´s fluid-dynamic in relation to the superficial gas velocity (Ug) in the range of 0.001 to 0.020 m/s. In order to evaluate the performance of the reactor, a preliminary assay was conducted with the ectomycorrhizal fungus Rhizopogonnigrescens. Better gas separationreflected in better liquid circulation and higher oxygen transfer (0.0197 1/s at 1 vvm) when compared to an operating, 2.3-L prototype airlift. According to this study, volumetric ...

Barbotage reactors such as airlift reactors (ALR) and bubble column reactors (BCR), due to their two-phase flow systems, were investigated in many research papers. In their basic design variants, they are typically used to lift, mix, and aerate liquids, while, when equipped with additional elements in hybrid variants, their individual properties, i.e., lifting, mixing, and aeration of liquids, can significantly change with the same reactor geometry. The object of this study was to develop a hybrid barbotage reactor in various structural design variants. The structure consisted of a barbotage column of 50 mm in diameter, used to transport a water–air mixture outside the reactor (so-called external loop). The installation was additionally equipped with a nozzle in order to improve mixture aeration and circulation efficiency. The nozzle was mounted at various heights of the column pump segment. Additionally, the reactor was equipped with s moving bed in two variants (20% and 40% reacto...

The main purpose of this work was to investigate the impacts of operating conditions and liquid properties on the hydrodynamic and mass transfer coefficient in a split cylindrical airlift bioreactor with oil-in-water micro-emulsions. Four different oil-in-water micro-emulsion systems containing kerosene, heavy naphtha, light naphtha and diesel as oil based was used with concentration ranging of 3%, 5% and 7% (v/v). The experimental results show that with an increase in the superficial gas velocity, gas holdup, Liquid circulation velocity and oxygen transfer coefficient increased and mixing time decreased. With increasing carbon atom numbers, resulted in a increase in the value of gas holdup , mixing time and volumetric mass transfer coefficient and a decrease in the value of liquid circulation velocity which was attributed to a decrease of surface tension, density and viscosity.

The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms &

A complete model for prediction performance of an oxidation airlift reactor has been developed. The model includes reaction kinetics, flow configuration, mass transfer and hydrodynamics. Liquid bulk and gas phases are modeled using a cell model. The mass transfer rates are computed from the film model. Hydrodynamics parameters are calculated with an adequate model based on balance equations and on experimental data. The model predicts the variations of concentrations and hydrodynamics parameters along the reactor and hence is able to provide a good description of the reactor.

Airlift reactors (ALRs) have great potential for industrial bioprocesses, because of the low level and homogeneous distribution of hydrodynamic shear. One growing field of application is the flue-gas treatment using algae for the absorption of CO 2. In this paper, we discuss the requirements for photosynthetic biomass growth in an ALR. The effects of the operating variables are analyzed using a mathematical model [Wu, X.; Merchuk, J. C. Simulation of Algae Growth in a Bench Scale Internal Loop Airlift Reactor. Chem. Eng. Sci. 2004, 59 (14), 2899] that accounts for the effects of ALR geometry, fluid flow, and illumination on the biomass growth. On the basis of the ALR principles and the specific requirements of photosynthetic processes, we developed a "triangular" ALR configuration that is particularly suitable for algal growth. We describe the design and operation of this novel bioreactor and present the first series of experimental data obtained for two different algal species in a pilot-scale unit supplied with flue gases from a small power plant. The measured removal efficiency of CO 2 was significant (82.3 (12.5% on sunny days and 50.1 (6.5% on cloudy days) and consistent with the increase in the algal biomass.

The interrelationships between the three parts of the airlift reactor, the riser, the downcomer, and gas-liquid separator, were examined with relation t o the overall mass transfer in the reactor. This involved studying the mass transfer o f oxygen f r o m the gas phase t o the liquid phase for 20 different reactor geometries. Both one-and two-sparger systems were studied. It was demonstrated that the gas-liquid separator plays a major role in reactor behavior and must be considered in reactor design. It was found that the overall reactor mass transfer coefficient KLA could be correlated to the pneumatic power of gas input per total dispersion volume (PIVD) and to the true riser superficial gas velocity JGR for all experimental conditions examined. The KLA is directly related to the PIVD with an exponent of approximately 1. "Two-sparger" systems, where an auxiliary gas sparger is placed near the downcomer entrance, have higher absolute values for KLA than single-sparger systems.

Hydrodynamics and mass transfer characteristics of a three-phase airlift reactor were studied in a rectangular splitvessel reactor and using an air-seawater-marine sediment system. Experiments were conducted over a range of downcomer to riser cross-sectional area ratios (AJAR = 0.65 to 1 .O) for two-phase systems and for five sediment concentrations (5 to 25% w/v) using marine sediments. The influence of higher sediment concentrations (30 to 50% w/v) was examined for AJAR = 1. The presence of fine sediment particles in the system had little effect on hydrodynamic and mass transfer parameters compared to the two-phase systems up to 25% loading, decreasing at higher loadings. The airlift reactor was found to meet the dissolved oxygen demand needed for a contaminated sediment treatment process. Axial distribution of the particles was uniform along the riser and the downcomer. Correlations were developed that described the hydrodynamic and mass transfer behaviour for all experimental conditions examined. On a etudie les caracteristiques de l'hydrodynamique et de transfert de matiere d'un reacteur airlift triphasique dans un reacteur divise rectangulaire pour un systeme air-eau de mer-sediments marins. Les experiences ont ete menees pour des rapports de sections de colonne ascendante sur colonne descendante (AJAR = 0,65 a I,O) pour des systemes biphasiques et cinq concentrations de sediments (5 a 25% de w/v) composees de sediments marins. L'influence de plus fortes concentrations de sediments (30 -50% de w/v) a ete examinee pour AJAR = I . La presence de fines particules de sediments dans le systeme a eu peu d'effet sur les parametres hydrodynamiques et de transfert de matiere, comparativement aux systemes biphasiques jusqu'a une charge de 25%, qui diminue a des charges plus elevees. On a trouve que le reacteur airlift satisfaisait la demande en oxygene dissous necessaire a un procede de traitement de sediments contamines. La distribution axiale des particules etait uniforme le long de la colonne montante et de la colonne descendante. On a etabli des correlations qui decrivent le comportement hydrodynamique et de transfert de matiere pour les conditions experimentales etudiees.

This paper presents the results obtained by the R&D of a multi-channel airlift photobioreactor for growing algae. The work consists of the design, construction, operation and characterization of a multi-channel airlift photobioreactor. Porphyridium Sp, a species of algae of commercial interest was tested. The description of the photobioreactor the experimental set up, and the data obtained in the indoor experiment using artificial solar radiation at the laboratory scale are presented.

The main purpose of this work was to investigate the impacts of operating conditions and liquid properties on the hydrodynamic and mass transfer coefficient in a split cylindrical airlift bioreactor with oil-in-water micro-emulsions. Four different oil-in-water micro-emulsion systems containing kerosene, heavy naphtha, light naphtha and diesel as oil based was used with concentration ranging of 3%, 5% and 7% (v/v). The experimental results show that with an increase in the superficial gas velocity, gas holdup, Liquid circulation velocity and oxygen transfer coefficient increased and mixing time decreased. With increasing carbon atom numbers, resulted in a increase in the value of gas hold-up, mixing time and volumetric mass transfer coefficient and a decrease in the value of liquid circulation velocity which was attributed to a decrease of surface tension, density and viscosity.

Hydrodynamic and mass transfer coefficient in a split-cylinder airlift reactor for four different oil-inwater micro-emulsions containing kerosene, heavy naphtha, light naphtha, and diesel as oil-based with concentrations of 3%, 5%, and 7 % (v/v) were considered. The experimental results showed that with increasing the oil in water ratio, the gas holdup increased but liquid circulation velocity and oxygen transfer coefficient decreased. Light naphtha with the lowest surface tension and viscosity had the maximum mass transfer and gas holdup, and the minimum liquid circulation velocity, while diesel with the highest surface tension and viscosity had the minimum mass transfer and gas holdup and the maximum liquid circulation velocity.

An integrated reactor model was designed in this research to simulate fluid dynamics, local light intensity and the growth rate of nitrogen-fixing cyanobacterium Cyanothece sp. ATCC 51142 in a flat-plate photo-bioreactor by CFD technique. Previous research had already given the parameters in different algal growth kinetic equations. In this research, parameters were modified by CFD technique to improve the accuracy of cyanobacterial growth kinetic models. Finally, effects of recycling gas flow rate and geometry of sparger on local light intensity, growth rate, and fluid dynamics were analysed. Results show that recycling gas flow can increase liquid velocity and bubble volume fraction, however it prevents light transmission and the growth of cyanobacterium. Geometry of the sparger can affect liquid movement and distribution of both local light intensity and local growth rate.

An Agrobacterium-transformed root culture of Solanum tuberosum was grown in a 15-I bubble column. The specific respiration rate decreased by a factor of ten as the tissue grew over a 25-day culture period. On days 5.8.13. and 21, respiration was shown to be independent of aeration rate over a range oj0. 05-0.4

Hydrogen sulfide (H 2 S) removal by the Lo-Cat process [reaction with iron(3+) chelates] consists of two steps: the removal reaction and catalyst regeneration. The internal loop gas lift or the autocirculation reactor is an appropriate reactor for the Lo-Cat process because it combines the reaction and regeneration steps in a single device. The removal reaction takes place in the riser, and the used catalyst solution is regenerated in the downcomer. This research involved the study of the performance of the Lo-Cat air-lift reactor on H 2 S removal under various operating conditions. H 2 S could be removed completely (>99.9%) when the superficial H 2 S velocity in the riser was 0.03 m/s and the superficial air velocity in the downcomer was 0.01 m/s. Iron(2+) ethylenediaminetetraacetic acid [Fe 2+ EDTA] was regenerated to Fe 3+ EDTA in the downcomer with a conversion of up to 79%. The conversions of H 2 S, Fe 3+ EDTA, and Fe 2+ EDTA decreased with increasing superficial gas velocity in the riser for a fixed gas velocity in the downcomer. This was due to the decrease in the liquid-phase circulation time in the riser and downcomer with an increase in the superficial gas velocity in the riser at a constant downcomer velocity. A mixing cell model for gas and liquid phases was also developed to describe the H 2 S degradation behavior of the reactor, and the model was found to be consistent with the measured data.

Air-lift reactors (ALRs) have great potential for industrial bioprocesses, because of the low level and homogeneous distribution of hydrodynamic shear. One growing field of application is the flue-gas treatment using algae for the absorption of CO 2 . In this paper, we discuss the requirements for photosynthetic biomass growth in an ALR. The effects of the operating variables are analyzed using a mathematical model [Wu, X.; Merchuk, J. C. Simulation of Algae Growth in a Bench Scale Internal Loop Airlift Reactor. Chem. Eng. Sci. 2004, 59 (14), 2899] that accounts for the effects of ALR geometry, fluid flow, and illumination on the biomass growth. On the basis of the ALR principles and the specific requirements of photosynthetic processes, we developed a "triangular" ALR configuration that is particularly suitable for algal growth. We describe the design and operation of this novel bioreactor and present the first series of experimental data obtained for two different algal species in a pilot-scale unit supplied with flue gases from a small power plant. The measured removal efficiency of CO 2 was significant (82.3 ( 12.5% on sunny days and 50.1 ( 6.5% on cloudy days) and consistent with the increase in the algal biomass.

This paper outlines the experimental work conducted for the optimization of the growth condition of micro algae Chlorella vulgaris. A series of three flat plate external loop air lift reactors with different surface area to volume ratios were specially constructed for the experimental investigations.

The gas flow rate is the main variable that is manipulated in order to change the mass transfer coefficient of CO2 into the reactors. Increasing the gas flow rate increases in mass transfer coefficient resulting in an increase in the Chlorella vulgaris growth rate. This increase in growth rate comes at a higher energetic cost associated with the pneumatic air input for mass transfer and mixing. The ratio between the energy contained within the biomass and the energy used in its cultivation is defined as the net energy ratio.

Experiments conducted in this study record the optical density, dry weight, temperature and pH of the three reactors under different rates of aeration. From this data, the growth rate, biomass concentration and energy contained within the algae biomass is calculated for each set of experiments conducted.

This data is compared across the different surface area to volume ratios to derive the trend exhibited. It was found that the reactor with the surface area to volume ratio of 36 achieved the highest maximum growth rate of 0.36 hr-1 and 0.28 hr-1 at a 3% CO2/air mixture flow rate of 1 l/min and 0.5 l/min respectively. The next highest growth rate of 0.18 hr-1 is achieved in the reactor with a surface area to volume ratio of 27 at a gas flow rate of 0.5 l/min.

The highest net energy ratio of 0.065 is achieved by the reactor with the largest surface area to volume ratio of 48 at a gas flow rate of 0.5 l/min. The next highest NER of 0.047 is recorded for the reactor with a surface area to volume ratio of 27 at a gas flow rate of 0.25 l/min.

Mass transfer and light measurement tests are conducted to understand the growth rate data recorded. It was found that the reactor with the highest surface area to volume ratio achieves the best mass transfer at all gas flow rates investigated. This is primarily due to a lower circulation speed identified in hydrodynamic studies. This lower liquid circulation speed results in a longer gas hold up which increases the efficiency of mass transfer. The reactor with a surface area to volume ratio of 27  results in the fastest rate of circulation which in turn results in a 6.78 fold increase in the mass transfer coefficient for a doubling of the volume air to volume liquid ratio from 0.11 to 0.22. The next highest jump in kLa of 1.57 is achieved by the reactor with a surface area to volume ratio of 36 for an increase in the volume air to volume liquid ratio from 0.07 to 0.14.