Microalgal growth in mixing culture systems

Transcription

1 Microalgal growth in mixing culture systems Mr.R.Rameshprabu, Ph.D. student, Department of Soil And Water Conservation, National Chung Hsing University, Taichung, Taiwan-402. Advisor : Prof. Paris Honglay Chen PhD MPH PE 30/06/2007 1

2 CONTENTS Introduction Biology of mixture culture systems Ecology of mixtural cultural systems Types of the systems High Rate Pond system Algae growth with nutrients in water bodies Preliminary lab results Conclusion 2

3 INTRODUCTION Biofuel to energy crisis Energy crops microalgae Pure cultures and mixture cultures Nutrients : chemicals & natural nutrients Mixtural culture systems 3

4 First year FIRST YEAR I st semester II nd semester Biology of Algae Algal Oil Biodiesel from Algae Algae Oil Extraction Cultivation of Algae Biodiesel Production from Algae Oil Ecology & Biology of mixtural cultural systems Types of the systems High Rate Pond Algae growth with nutrients in water bodies Preliminary lab results 4

5 Biology of mixtural cultural systems Eukaryotic and prokaryotic Microalgae, Macro algae Autotrophic/Heterotrophic Multicellular or Unicellular Growing in aqueous environment (streams & open ponds) moist soil on the surface of moist rocks and wood living with fungi and lickens 5

6 Haematococcus pluvialis 6

7 Micractinium quadrisetum 7

8 Micractinium pusillum 8

9 Scenedesmus dimorphus 9

10 Chlorella pyrenoidosa 10

11 Botryococcus braunii 11

12 Ochromonas danica 12

13 Ecology of mixtural cultural systems Primary producers in aquatic ecosystems. found in damp places or bodies of water. common in terrestrial as well as aquatic environments. Symbiosis with fungus and lichen. algae play significant roles in aquatic ecology 13

14 Algae Tree Source: 14

15 Microalgae classification Phytoflagellates Dinoflagellates Diatoms 15

16 Types of the systems Aerobic Zone Facultative Zone Anareobic Zone 16

17 Biological classification of system Aerobic system An aerobic pond contains bacteria and algae in suspension; aerobic conditions (the presence of dissolved oxygen) prevail throughout its depth. 3-5 feet. Anaerobic system without any dissolved oxygen throughout their entire depth. it is highly efficient in destroying organic wastes. Anaerobic ponds are >14 feet in depth with an organic loading of lbs BOD5 per acre per day. 17

18 Facultative system 4-8 feet deep with an organic loading of lbs BOD5 per acre per day A surface zone where aerobic bacteria and algae exist in a symbiotic relationship; An anaerobic bottom zone in which accumulated solids are actively decomposed by anaerobic bacteria. An intermediate zone that is partly aerobic and partly anaerobic in which the decomposition of organic wastes is carried out by facultative bacteria. These ponds are often referred to as facultative ponds. 18

19 Maturation system Maturation pond system are shallow ( m) and show less vertical stratification, and their entire volume is well oxygenated throughout the day. Their algal population is much more diverse than that of facultative ponds. On the other hand, maturation ponds only achieve a small removal of BOD5, but their contribution to nitrogen and phosphorus removal is more significant. It should be emphasized that most ammonia and nitrogen is removed in maturation ponds. 19

20 High Rate Pond system HRPs are designed to promote algae growth. They are shallow ( m) in order to allow maximum light penetration. They can operate at short hydraulic retention time (HRT) in the range of 4 to 10 days depending on climatic conditions reducing the required surface area. Continuous mixing is provided to keep the cells in suspension and to expose them periodically to light. The most common design that has proven successful at large scale is the single loop paddlewheel mixed. Due to energy cost dependence on velocity, most ponds have been operated at velocities from l0 to 30 cm/ sec (Dodd, 1986). More recently, a special flow pattern was introduced to improve the efficiency of this type of ponds (Mihalyfalvy et al., 1998). 20

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22 Diagram of top and side views of each experimental HRP 22

23 Figure, The main processes involved in a high rate algal p ond, extracted from Oswald and Gotaas (1957). The process was developed in shallow ponds, less than a m eter deep and continuously stirred with paddle wheels. These, so called high rate algal ponds (HRAP), were aerob ic throughout their volumes in contrast to facultative ponds which are anoxic near the bottom (Oswald, 1988a). The HRAPs are often built as so called raceways, with a m eandering configuration. Properly designed and operated H RAPs are capable of removing more than 90% of the BOD and up to 80% of the nitrogen and phosphorus (Oswald, 19 88b). 23

24 Cross section of paddle wheel 24

25 Algae growth with nutrients in water bodies 25

26 Preliminary lab results 26

27 CONCLUSION High Rate Algal Ponds are efficient, HRAP is the best method of large scale biomass production. Algae can be used to make biodiesel 27

28 Suggestions To develop efficient algae production methods 28

29 Thank you very much for your time & attention!! 29