Nutrients assessment of anaerobic palm oil mill effeluent (AnPOME) as an alternative media for microalgae culture

The main aim of the present study is to investigate the availability of macronutrient andmicronutrient in AnPOME. All collected samples were analyzed using HACH method. Theresults reveal that the C/N and N/P ratio of the AnPOME is six times more than the theoreticalvalue. Concentration of micronutrients also shown higher concentration range compared tothat of the Bold Basal Medium (BBM). However, the concentration of phosphorus inAnPOME six times lower than nitrogen indicates that phosphorus limitation in AnPOME.Hence, this finding suggested the best microalgae to be grown in AnPOME is mixotrophic orheterotrophic mode. Overall, reuse of AnPOME replacing synthetic growth is highlyrecommended considering that enough composition of macronutrient and micronutrient inAnPOME and inexpensive alternative to synthetic media.Keywords: microalgae; Anaerobic Palm Oil Mill Effluent (AnPOME); BBM; macronutrient;micronutrient

Performance of oscillatory flow reactor and stir tank reactor in solvent fermentation from palm oil mill effluent

Advance in mixing technology has developed a new way of mixing fluids by introducing an oscillatory motion to replace the conventional mechanical agitation or an air bubble displacement. This new way of mixing breakthrough has been implemented in an Oscillatory Flow Reactor (OFR). This research will be focus on the performance of OFR as a bioreactor by comparing with Stir Tank Reactor (STR), which is the traditional device in fermentation. The experimental work was conducted in an OFR and a STR with a working volume of 1.5 l. Solvent production strain, Clostridium acetobutylicum NCIMB 13357 was grown in OFR and STR, using fresh Palm Oil Mill Effluent (POME) as growth medium. All of the experiments were conducted anaerobically under batch mode for 72 hours at constant temperature of 35°C. Comparisons of the growth trend and solvent fermentation performance for both devices were investigated. Total solvents (acetone, butanol and ethanol) produced in an OFR was comparable with that of STR. Total solvents production in OFR is 1.8 times higher than that of STR resulted in total 1.6 g/l of solvents. The results of this investigation showed that OFR has an excellent potential as an alternative device in fermentation processes

Determining potential of subcooling to attenuate hydrodynamic instabilies for steam-water two phase flow

Hydrodynamic instabilities are regarded as important but are undesirable occurrences for the systems used in process industries, which involve steam. These instabilities affect to a great extent the life line of the safe operation of their systems by inducing thermal stresses and steam induced water hammers. On the basis of system operational analysis, it was found that condensation induced hydrodynamic instabilities were responsible for one third of the destructive events in steam driven systems and their attributes in power and process industry. Thus it becomes vital to investigate the influence of critical parameter such as sub-cooling to curb the destructive effects due to hydrodynamic instabilities on to the process equipment. Here for steam water two phase flows, the attenuation of hydrodynamic instabilities due to sub-cooling and inlet pressure has been investigated. It was found that sub-cooling has more pronounced and notable effect on the attenuation of these instabilities

Experimental and Numerical Investigations of Heat Transfer Characteristics for Impinging Swirl Flow

This paper reports experimental and computational fluid dynamics (CFD) modelling studies to investigate the effect of the swirl intensity on the heat transfer characteristics of conventional and swirl impingement air jets at a constant nozzle-to-plate distance (L = 2D). The experiments were performed using classical twisted tape inserts in a nozzle jet with three twist ratios (y = 2.93, 3.91, and 4.89) and Reynolds numbers that varied from 4000 to 16000. The results indicate that the radial uniformity of Nusselt number (Nu) of swirl impingement air jets (SIJ) depended on the values of the swirl intensity and the air Reynolds number. The results also revealed that the SIJ that was fitted with an insert of y = 4.89, which corresponds to the swirl number Sw = 0.671, provided much more uniform local heat transfer distribution on the surface. The CFD-predicted results help to explain the experimental measurements in terms of the turbulence intensity. Furthermore, the predicted and measured local Nusselt numbers were consistent with each other

Numerical Investigation of Heat Transfer and Friction Factor Characteristics in a Circular Tube Fitted with V-Cut Twisted Tape Inserts

Numerical investigation of the heat transfer and friction factor characteristics of a circular fitted with V-cut twisted tape (VCT) insert with twist ratio (y=2.93) and different cut depths (w=0.5, 1, and 1.5 cm) were studied for laminar flow using CFD package (FLUENT-6.3.26). The data obtained from plain tube were verified with the literature correlation to ensure the validation of simulation results. Classical twisted tape (CTT) with different twist ratios (y=2.93, 3.91, 4.89) were also studied for comparison. The results show that the enhancement of heat transfer rate induced by the classical and V-cut twisted tape inserts increases with the Reynolds number and decreases with twist ratio. The results also revealed that the V-cut twisted tape with twist ratio y=2.93 and cut depth w=0.5 cm offered higher heat transfer rate with significant increases in friction factor than other tapes. In addition the results of V-cut twist tape compared with experimental and simulated data of right-left helical tape inserts (RLT), it is found that the V-cut twist tape offered better thermal contact between the surface and the fluid which ultimately leads to a high heat transfer coefficient. Consequently, 107% of maximum heat transfer was obtained by using this configuration

Penilaian model matematik bagi pertumbuhan mikroalga Characium sp. UKM1, Chlorella sp. UKM2 dan Coelastrella sp. UKM4 dalam air larut resapan sintetik

Mikroalga berpotensi sebagai agen fikoremediasi air sisa dan metabolit yang terhasil dalam biojisim mikroalga mampu diaplikasikan dalam bidang bioteknologi. Pertumbuhan mikroalga dalam air sisa menjadi petunjuk bahawa mikroalga mampu hidup dalam persekitaran ekstrim dan menjadi agen fikoremediasi air sisa. Oleh itu, model matematik yang terbaik bagi kinetik pertumbuhan mikroalga yang dikultur dalam air sisa perlu dikaji bagi menentukan model yang tepat untuk digunakan pada masa akan datang. Dalam kajian ini, penilaian model matematik yang terbaik terhadap tiga mikroalga tempatan, Characium sp. UKM1, Chlorella sp. UKM2 dan Coelastrella sp. UKM4 yang dikultur dalam air larut resapan sintetik dianalisis dengan menggunakan tiga model matematik iaitu logistik, logistik terubah suai dan Gompertz terubah suai. Selain itu, analisis statistik dijalankan bagi penentuan model terbaik dengan mengambil kira nilai regressi terubah suai (adj R2), ralat tambah kuasa dua (SSE), punca min ralat kuasa dua (RMSE), faktor bias (BF), faktor kejituan (AF) dan peratus ramalan ralat piawai (%SEP). Hasil menunjukkan model yang terbaik bagi ketiga-tiga mikroalga dalam air larut resapan sintetik adalah model Gompertz terubah suai. Ini disebabkan oleh beberapa ciri antaranya plot residual yang mendekati model matematik, nilai BF yang mendekati nilai satu, serta nilai terendah %SEP berbanding model matematik yang lain. Kesimpulannya, model Gompertz terubah suai adalah model penyesuaian yang terbaik terhadap pertumbuhan mikroalga dalam air larut resapan sintetik

NUMERICAL SIMULATION OF FLUID FLOW BEHAVIOUR ON SCALE UP OF OSCILLATORY BAFFLED COLUMN

The fluid dynamics of oscillatory flow in a baffled column of 145 mm diameter was investigated numerically in this work. This numerical simulation was carried out by a 2D laminar unsteady solver using CFD package Fluent® 6.3. From the simulation, data on surface velocity were collected and velocity ratio was calculated to determine the intensity of mixing which were the main operating parameters in oscillatory flow in a baffled column. The suitable operating parameters of oscillatory baffled column of 145 mm diameter were also determined in this work. It was found that the oscillation amplitude was more dominant for obtaining desirable mixing results compare to oscillation frequency

Application of Electrical Resistance Tomography in an Oscillatory Baffled Column for Gas-Liquid Two-Phase Flow

Oscillatory baffled column (OBC) has a high potential for industrial application especially contacting gas and liquid phase. However, there are still lacks of research regarding the dynamics of gas-liquid phase specifically on the visualization of internal flow. Electrical Resistance Tomography (ERT) technique has capabilities to visualize mixing process internally without invading the flow. The objective of this study is to investigate the gas-liquid mixing distribution in an OBC by applying tomography technique model ITS P2000 of ERT system. The parameters investigated are phase distribution, gas hold up and power density. The experimental work was carried out in an OBC with a diameter of 145 mm and 720 mm height. The column is consisted of four planes of sixteen stainless steel ERT electrodes. The results of the research have shown that 70 mm of oscillation amplitude and 2 Hz of oscillation frequency give the best result with 73% of gas hold up and 12433.39W/m3

Assessment of biohydrogen injection system through Arduino setting in photosynthetic and dark fermentation by local microalgae culture

Biohydrogen (a hydrogen gas produced by biological methods) is one of the most sustainable sources of energy for electricity generation. Hydrogen gas combustion produces only water without the release of greenhouse gases emission. Microalgae are the microorganisms that can produce biohydrogen through photosynthesis and dark fermentation. In this study, the local microalgae isolate, Chlamydomonas sp.UKM6 has been used to generate biohydrogen using both fermentation methods under anaerobic conditions. Photosynthesis fermentation was carried out using the live culture of UKM6 under continuous illumination while dark fermentation was carried out using the biomass of UKM6 with the palm oil mill effluent (POME) sludge as an inoculum. The resulting hydrogen gas is automatically injected into the fuel cell system using the newly developed Arduino Uno. Using data presented from the Arduino settings program, the biomass of UKM6 in dark fermentation produces the highest hydrogen gas and voltage at 30.89 ppm and 0.92 mV, respectively. Based on the results, it can be concluded that microalgae have the potential to generate energy through the production of biohydrogen which can be further analyzed using fuel cell technology. This system can be further improved in the future to measure energy generated directly and effectively

Kinetic Model of Thermophilic Biohydrogen Production from POME

The study of fermentation kinetic parameters are crucial to understanding the environmental factors affect on biohydrogen production. Kinetic models for hydrogen production from anaerobic digestion of palm oil mill effluent (POME) by mixed culture were developed based on published work. The models accounted for substrate limitation, substrate inhibition, hydrogen production, and endogenous decay rate. Data from previous literature were used to compare four microbial growth kinetic models for hydrogen production in an ASBR system. The estimated values of the maximum specific growth rate (μm) were found to be 0.371 h-1. In this study, the parameters of Y, kd, and B0 calculated were 2.64 gVSS/gCOD, 0.053 h-1, and 0.133 L H2/gCOD, respectively. The model fitting was found to be in good agreement with the experimental and can be utilized for the optimization and design of the process