CD Disertasi

Penyerapan CO2 Oleh Mikroalga (Chlorella Pyrenoidosa) Pada Photobioreaktor

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Global warming caused by Greenhouse Gas (GHG) has been the concern and an important challenge this century. Carbon dioxideor CO2 is main contributor to GHG. Methods to reduce and capture CO2 emissions using various processes have been widely proposed and researched to address CO2 emissions generated from industry. Another method is to capture CO2 biologically using microalgaethat gets increased attention and continuously researched and developed as one of the methods to capture CO2 emissions (called CO2 Biofixation) such as those originating from power generation industries.However, further researchesto support biofixation are still needed in area of CO2-tolerant microalgae identificationincluding the use of flue gas as a source of CO2, environmental factors affecting the growth and the economics of biofixation. Therefore it is the aim of study to contribute knowledge in those aspects.

The research was divided into 4 parts.The first part wastolerance test of C.pyrenoidosa and Arthrospira.sp microalgae to high concentration of pure CO2 10% (100,000 ppm) as a rapid screening between the two microalgae in term of their tolerance and adaptability to high CO2 concentration; The second part was a study aims to evaluate the effect of environmental factors in this case the combination of light intensity factor (2000 lux, 4000 lux, 6000 lux and 8000 lux) and photoperiod or cycle duration of light L and dark D (L/D: 8h/16h, 12/h/12h, 16h/8h where h was hours)on the performance of CO2 absorption and growthof selected microalgae from first part (in this case the C.pyrenoidosa); third part was toanalyze the influence of using CO2 source from flue gas out of fossil fuel combustion from mini power generation (0.0038 MW) to CO2 absorption performance and growth of the selected microalgae- C.pyrenoidosacompared to its culture control supplied with CO2 from ambient air; and fourth part was economic evaluation of several scenarios with aneconomic probabilistic evaluation approach including the scenario of CO2 biofixation from 0.0038 MW capacity power generation.

C. pyrenoidosa showed better tolerance to pure CO2 with high concentration of 10% (100,000 ppm) than Arthrospira.sp (Spirulina) based on growth performance and adaptation to pH change.

Both factors of light intensity and photoperiod factor were statistically significant to CO2 biofixation and growth performance of C.pyrenoidosa. It was found that in the growth profile of C.pyrenoidosa, the duration of C.pyrenoidosa cultures can last longer before entering the decline phase at condition of light intensity 8000 lux and photoperiod L/D of 16h/8h than the otherconditions of light intensity and photoperiod used in this study. Light regime with light intensity in the range of 6000 lux and 8000 lux and photoperiod between L/D 12h/12h and L/D 16h/8hprovides best route for biomass, specific growth and rate of CO2 biofixation of C.pyrenoidosa. CO2 biofixation rate valueachieved was 0.267under light intensity conditions of 8000 lux. The highest growth performance of C.pyrenoidosaobtained as biomass was 0.516 gr/l at light intensity of 8000 lux and photoperiod L/D 16/8 hours; and specific growth rate obtained was 0.447 (1/day) at light intensity of a 8000 lux and photoperiod L/D 12/12 hours.

Supply of flue gas containing a high CO2 concentration of 60,000 ppm resulted in a significantly higher performance of C.pyrenoidosa outdoor culture with flue gas compared to the performance its control outdoor culture with CO2 supplied from ambient air. The study also showed that percentage of absorption of CO2 by C.pyrenoidosaoutdoor culturewas 77.9% to 88.6% with median value of 82.73%when supplied withflue gas containing high concentration of CO2(about 60,000 ppm) to the culture. The decrease in pH caused by the administration of flue gas with high CO2 concentration up to 60,000 ppm in this study did not negatively affect the performance of CO2 absorption derived from flue gasas indicated by the rate of CO2biofixation of 0.226 ± 0.012 (gr/liter/day), as well as the growth performance of C.pyrenoidosa indicated by the highest biomass achieved in the condition was 0.590 ± 0.053 (gr/liter), and also the specific growth rateof 0.408 ± 0.019 (1/day). The results suggest that flue gas can be used as an alternative source of CO2 for the cultivation of C.pyrenoidosa microalgae.

Economic evaluation showed that by comparing probabilistic NPV values in all scenarios employed in this research, Scenario C has better economic value and is more competitive than other scenarios. The Scenario C is the scenario of flue gas utilization from the burning of fossil fuels at power plants with capacity of 0.0038 MW and projection on a 150 MW capacity scale for used as an alternative CO2 source for microalgae cultivation.There is a 76.7% chance of a positive NPV from Scenario C being achieved for a capacity of 0.0038 MW with an NPV value of less than Rp800 million and for the capacity of 150 MW there is 80.95% NPV possibility to the positive direction with the value of NPV less than Rp25 trillion.

Therefore based on all of analysis and evaluation in this research,it is concluded that the absorption of CO2 by using microalgaeor CO2 biofixation such as employing microalgae C.pyrenoidosaused in this research has great potential to be developed further in Indonesia to help overcome the problem of CO2 emission from industry especially power plant industry.

Key words: Global warming, Carbon dioxide, CO2 Biofixation, Chlorella pyrenoidosa, environmental factor, light intensity, photoperiod, flue gas, probabilistic econonomic

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Ketersediaan

Informasi Detail

Judul Seri

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No. Panggil

10 01. 318 (0007)

Penerbit

Pekanbaru : Universitas Riau – Pasca Sarjana – Disertasi Ilmu Lingkungan., 2018

Deskripsi Fisik

xxx, 176 hlm.; ill.; 29 cm

Bahasa

Indonesia

ISBN/ISSN

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Klasifikasi

10 01. 318 (0007)

Tipe Isi

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Tipe Media

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Tipe Pembawa

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Edisi

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Subjek

PASCASARJANA (DISERTASI) ILMU LINGKUNGAN

Info Detail Spesifik

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Pernyataan Tanggungjawab

FATAH

Versi lain/terkait

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