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Algae Bioreactor System for the UBC Power House Chen, Gang; Deviato, Alessandro; Kras, Simon 2010-04-16

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         SEEDS Student Reports    1 UBC Social, Ecological Economic Development Studies (SEEDS) Student Reports            Algae Bioreactor System for the UBC Power House  Gang Chen Alessandro Deviato Simon Kras University of British Columbia CHBE 484 April 2010          Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report.”  CHBE 484   Gang Chen Alessandro Deviato Simon Kras  University of British Columbia  April 16th 2010 ALGAE BIOREACTOR SYSTEM FOR THE UBC POWER HOUSE CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010  Chen, Deviato, & Kras - i - EXECUTIVE SUMMARY In the last 20 years, the use of algae bioreactors has been gaining popularity.  Fuel produced by algae bioreactors can be in the form of methane or in the form of lipids, which can be converted to biodiesel. Certain species of algae such as Botryococcus Braunii and Chlorella vulgaris have especially high lipid contents when starved of nutrients and are therefore ideal candidates for biodiesel production. The major requirements of all photoautotrophic species, including algae, are light, carbon dioxide and nutrients.  All three requirements are naturally available, making open-air bioreactors the most common type.  However, closed photo-bioreactors (PBRs) are becoming increasingly common, since they provide increased exposure to sunlight, increased growth rates, and consequently, increased production on a given area of land.  CO2-rich flue gas can be used fairly readily by closed PBRs to increase the rate of production by providing a source of heat and carbon. A study was done in 2008 to assess the feasibility of a closed PBR situated on the roof of the Leonard S. Klinck (LSK) building at UBC, using flue gas from the UBC powerhouse.  In her study, Christine Hung suggested that a PBR using B. Braunii would be economically feasible, in large part due to production of biodiesel.  In this study we have sought to consider whether using different algal species, or incorporating wastewater as a reactor medium would improve the performance of the proposed PBR.  We have provided a short background of microalgae production, conducted an analysis concerning the use of Chlorella vulgaris, Nannochloropsis oculata and Scenedesmus sp, and determined the cost of pumping wastewater from the current sewer system to a PBR on the roof of the LSK building. We are unable to replicate Hung’s calculations, and based on our analysis, the proposed PBR is not economically feasible.  The expected annual revenue for B. Braunii  is $32,600, and the annual expense instalments are $1.1 million.  Scenedesmus sp. was deemed to be the best performer with expected annual revenue of $70,000. The capital and operating costs over a ten year period associated with pumping wastewater from the existing sewage lines to the proposed PBR are $8,700 annually.    CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010  Chen, Deviato, & Kras TABLE OF CONTENTS  SUMMARY………………………………………………………………………………. i 1.0 INTRODUCTION…………………...…………………………………………….……… 1 2.0 BACKGROUND…...………...…………………………………………………….……... 1  2.1   HOW A BIOREACTOR WORKS…………………………………........................... 1  2.2   BIODIESEL PROCESS USING ALGAL ..........................………………………… 2  2.3   SUCCESFULL IMPLEMENTATIONS………………………….…………………. 3          2.3.1   ENVIRONMENTAL PPLICATIONS…….……………………...………….. 3          2.3.2   SPECIALTY CHEMICALS AND BIOACTIVE COMPOUNDS…………. 3 3.0 OPTIMIZATION OF A UBC ALGAE PHOTOREACTOR……………………………... 4  3.1   PREVIOUS FEASIBILITY ANALYSIS……………………………………………. 4  3.2   HYDROCARBON YIELD WITH VARYING SPECIES OF ALGAE…………….. 5  3.3   SECONDARY WASTEWATER EFFLUENT AS A GROWTH MEDIUM………. 6 4.0 TRANSPORTING WASTEWATER TO UBC POWER HOUSE……..………………… 6  4.1   DESIGN OF SEWER LINE ADDITION……………...……………………………. 7  4.2   PRICE ANALYSIS OF MATERIALS…………………………………………….... 9  4.3   PRICE ANALYSIS OF CONSTRUCTION……..………………………………….. 10  4.4   PUMP SIZING…………………………………...………………………………….. 11  4.5   TOTAL COST……………………………...………………………………………... 12 5.0 OPPORTUNITIES FOR FUTURE WORK………………………………………………. 13 6.0 CONCLUSION & RECOMMENDATIONS……………………………………………... 14 7.0 NOMENCLATURE………………………………………………………………………. 15 8.0 REFERENCES………………………………………………………………………......... 16  APPENDIX A: SAMPLE CALCULATIONS APPENDIX B: FIGURES & DATA  CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010  Chen, Deviato, & Kras List of Tables TABLE 1.  MATERIALS PRICE BREAKDOWN…...…………………………………….... 10 TABLE 2.  TOTAL COST BREAKDOWN…………………………...……………………... 13 TABLE 3.  SUMMARY OF PARAMATERS……..………………………………………… 13  List of Figures FIGURE 1.  SCHEMATIC OF BIODIESEL PROCESS WITH PBRs………..…….……….. 2 FIGURE 2.  IMAGE OF RACEWAY BIOREACTOR……………………………………… 6 FIGURE 3.  TOP-VIEW OF PROPOSED SEWER ADDITION…………………..……....... 8 FIGURE 4.  SATELLITE VIEW OF PROPOSED SEWER SITE…….…...…………….….. 9 FIGURE 5.  IMAGE OF RECOMMENDED PUMP…………...……...…...…………….….. 11 FIGURE 6.  PUMP CURVE WITH RELATIVE EFFICIENCY .........…...…………….…… 12 CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  - 1 - 1.0 INTRODUCTION Renewable energy is currently the subject of intense research due to the focus on reducing greenhouse gas (GHG) emissions, and finding energy alternatives to fossil fuels. Biofuels are a promising renewable energy source that has attracted attention in recent years. However, first generation biofuels primarily obtained from food crops and oil seeds are limited in their capacity due to their extensive land requirement, often competing with agricultural land use (Reinhardt G et al., 2008). These concerns have steered scientific and engineering research towards intensive biomass productions through non-food organisms such as microalgae. The basis for this report is the undergraduate thesis created by Christine Hung in 2008, which examines the feasibility of an algae bioreactor fed by the UBC powerhouse flue gas.  The motivation of this literature-based study is to address a few of the items left pending by Hung in her thesis.  A brief introductory background will be provided on algae bioreactors, followed by an examination of the feasibility of using different algal species at UBC.  The use of wastewater as a growth medium will also be examined.  2.0 BACKGROUND 2.1 How a Bioreactor Works According to researcher T.M. Mata, a bioreactor is defined as a system in which a biological conversion or reaction is achieved (Mata et al, 2009). Therefore, a photo-bioreactor is a reactor in which phototrophs (microbial, algal or plant cells) are cultivated or utilized to carry out a photo-biological reaction. Although this definition may be valid for both closed and open-culture systems, for the purpose of this article the definition is limited to the close-culture systems. Photo-bioreactors (PBRs) are flexible systems that can be optimized according to the biological and physiological characteristics of the particular algal species being used, allowing for species’ selection based on the desired products.  In a PBR, direct exchange of gases and contaminants (i.e. microorganisms, dust) between the grown cells and atmosphere are limited or not allowed by the reactor’s walls.  In addition, a large amount of light must cross the transparent reactor walls.  CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  - 2 - 2.2 Biodiesel Process Using Algal PBRs Error! Reference source not found. shows a schematic representation of the algal biodiesel process. It starts with the selection of algae species, followed by the design and implementation of PBRs for algae growth. After the PBRs, the biomass harvesting, processing and oil extraction are the typical unit operations for biodiesel production unit. Depending on the local conditions and available materials PBR’s design varies in size, shape, construction materials, inclination and agitation type. PBRs can be classified on the basis of both design and mode of operation. Generally, vertical tubular or flat-plate reactors are relatively cheap, easy to clean up, and have a large illumination surface, high mass transfer, and good mixing with low shear stress (Diane Greer, 2009). Those advantages play an important role in productivity. Limitations include the cost and complex construction. In addition, since diameter and height cannot be too large, a significant number of units are necessary to process the desired amount of waster water and flue gas.  Figure 1. Schematic of biodiesel process with PBRs (Source: T.M. Mata et al, 2010)   CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  - 3 - 2.3 Successful Implementations 2.3.1 Environmental Applications Production of biodiesel and other bio-products from algae can be more environmentally sustainable, cost-effective and profitable if combined with processes such as wastewater and flue gas treatments. Flue gas CO2 emissions as algae nutrient Flue gases from power plants are responsible for more than 7% of the total world CO2 emissions from energy use (Kadam KL., 1997), providing a CO2-rich source for algae cultivation and a potentially more efficient route for CO2 bio-fixation. Therefore, the use of flue gas emissions from fuel-fired power plants as a source of CO2 for algae growth is expected to contribute to reducing CO2 emissions and may offer a promising alternative to current GHG emissions mitigation strategies. Wastewater nitrogen and phosphorous as algae nutrients Aslan and Kapdan used the algae C.vulgaris for nitrogen and phosphorus removal from wastewater with an average removal efficiency of 72% for nitrogen and 28% for phosphorous (from 3 to 8 mg/L NH4+ and 1.5-3.5 mg/L PO4-3). 2.3.2 Specialty Chemical and Bioactive Compounds Depending on the algae species, various high-value chemical compounds can be extracted such as pigments, antioxidants, b-carotenes, polysaccharides, triglycerides, fatty acids, vitamins, and biomass, which are largely used as bulk commodities in different industrial sectors (e.g. pharmaceuticals, cosmetics, nutraceuticals, functional foods, and biofuels). Algae applications in human health Traditionally, nutritional supplements derived from plants have been used and dominate the marketplace. However, the health benefits of aquatic microorganisms such as algae are still being investigated and their recognition and appreciation has been only within the last three to four decades, largely linked to the introduction of probiotic supplements (Barrow C, Shahidi F., 2008). Microalgae are treated as having a protein quality and value greater than other vegetable sources (e.g. wheat, rice, and legumes), but poorer than animal sources (e.g. milk and meat). CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  - 4 - Algae for aquaculture and animal feed So far, microalgae culture has been more successful for food source and feed additive in the commercial rearing of many aquatic animals (i.e. rearing larvae and juveniles of many commercially important fish)  both freshwater and marine (T.M. Meta et al., 2010).  3.0 OPTIMIZATION OF A UBC ALGAE PHOTOREACTOR 3.1 Previous feasibility analysis Previous research has suggested that it may be economically viable to use an algae bioreactor to capture flue gases from UBC’s powerhouse in order to produce biodiesel (Hung, 2008).  Hung proposed an airlift PBR using Botryococcus braunii, operating at 25°C.  Several issues were left for future consideration including the following: 1. The heat transferred from the flue gas to the medium was not sufficient to maintain the 25°C design temperature of the PBR.  The option of bypassing the powerhouse’s economizer in order to capture more heat was brought up for further consideration. 2. B. Braunii is a relatively slow growing species of algae.  Faster growing species such as Chlorella vulgaris were suggested for future consideration. 3. The effects of light in the reactor, potentially causing photoinhibition due to excessive exposure, were not considered, and may be worth investigating. 4. Detailed hydrodynamical analysis of a PBR was not carried out, and was considered to be an issue worthy of bench-scale or full scale testing. 5. Seasonal discrepancies in production capacity and flue gas availability were not considered, and the possibility of CO2 sequestration in winter months to supplement biodiesel production in the sunny summer months was suggested. 6. The possibility of illumination systems such as optical fibres was presented, allowing the system to be placed indoors and kept warmer. CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  - 5 - 7. The production of methane and hydrogen were left for future consideration, as was the possibility of capturing oxygen to improve the powerhouse efficiency. Other issues which were left unaddressed, but not mentioned by Hung include: 1. Means of cooling the bioreactor during the summertime, when the PBR may overheat, resulting in cell damage and reduced productivity. 2. In order to house a bioreactor farm on the rooftop of the Leonard S. Klinck building, major structural improvements would likely be required.  The cost of these improvements was not considered in Hung’s economic analysis. 3. The conversion and separation processes necessary to obtain biodiesel from an algae feedstock were not accounted for in the economic analysis. 4. There are numerous other species of algae to consider besides B. braunii and C. vulgaris. 5. The nutrient requirements of the PBR were not accounted for in the economic analysis. Based on the scope of this report, item 4 from the above list was chosen as a focal topic.  In addition to Chlorella vulgaris, two other promising species of algae were considered: Nannochloropsis oculata and Scenedesmus sp.  Item 5 will also be addressed with a focus on the use of secondary wastewater effluent for nutrient supplementation. 3.2 Hydrocarbon Yield with varying species of algae In order to determine the economic viability of a PBR using various species of algae, an attempt was made to reproduce the calculations carried out by Hung (2008), using B. braunii as an algal species. These verifications did not agree with the values obtained by Hung.  The calculated annual hydrocarbon yield was 22.3 m 3  (compared to the value of 37 m 3  obtained by Hung).  The projected income was $32,600 (compare with $4.77M obtained by Hung).  Detailed calculations are shown in Appendix A. Based on a specific growth rate of 0.60/day (Ratchford and Fallowfield, 1991) and a lipid content of 20% (Mata, 2009), Scenedesmus species performed the best, with an annual CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  - 6 - hydrocarbon yield of 45.13 m 3  and a revenue of $70,000 per year.  C. vulgaris performed comparably to B. braunii, and N. oculata performed less favourably. Since the capital and operating costs for the system are $1.1 million per year (Hung, 2008), the PBR is clearly not economically viable as designed.  In addition, based on calculations found in the next section, the cost of the new sewer line would add $8,700 annually over a ten year period. It should also be noted that the cost of any structural upgrades to the Leonard S. Klinck building in order to resist greater loads at the rooftop have not been accounted for. 3.3 Secondary wastewater effluent as a growth medium Wastewater can often be used as a source of nutrients for a PBR (El Hamouri, 2003).  Domestic wastewater is considered to be nutrient poor, with typical nitrogen and phosphorus concentrations of 10-15 μg/L and 0.5-1 μg/L respectively in secondary effluent. Scenedesmus sp. was proposed by Xin et. al (2010) due to its low nutrient requirements.  Since nutrient starvation can benefit biodiesel production in a bioreactor by forcing algae to produce more lipids, a nutrient poor medium may in fact be optimal (Mata et al., 2009).  4.0 TRANSPORTING WASTEWATER TO UBC POWER HOUSE The implementation of a bioreactor above the Power House requires an addition to the current UBC sewer system to divert wastewater. The current sanitary sewer system in place at UBC is quite intricate. The Northern campus, which is of primary interest to the project, consists of three main trunks that are fed from smaller capillary lines attached to surrounding buildings and two large pump catchments (Alpin & Martin, 2001 as cited in Grant et al., 2001). These three main gravity driven trunks and the two catchments join to a single sewer that runs north towards Figure 1: Raceway bioreactor CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  - 7 - Northwest Marine Drive and feeds into the City of Vancouver’s Spanish Banks Interceptor. The city interceptor line eventually runs to the Iona Island Wastewater treatment facility (North Campus Neighbourhood Plan, 2004). 4.1 Design of Sewer Line Addition The wastewater, which is used to supply the algae with nutrients, will be diverted off one of the existing main sewer trunks in north campus. Due to the physics of pulling a liquid, it is only possible to raise a column approximately ten metres when placing the pump on top of the roof. Since the UBC Power House is within this height range, it is advised that the wastewater should be pumped up from the bottom rather than pulled up from the top to maximize efficiency. After the wastewater is pumped to the roof of the Power House, where the bioreactor is located, it will return to a gravity powered path down from the roof and back into the same main sewer trunk that it originated from (Figure 3 on the following page). It should be noted that ideally the supply of nutrients should come from secondary effluent, which in the future could be directed from a UBC wastewater treatment facility. For this project and the simplicity of calculations it is assumed that the wastewater can come directly from the existing sewer lines. According to the 2009 Edition of the UBC Technical Guidelines the following must be met when constructing new sanitary sewer lines:  Sanitary sewers shall be designed using Peak Wet Weather Flow (PWWF), which is the Peak Dry Weather Flow (PDWF) plus 500 litres per diameter of pipe (m) per length of pipe (m) per day.  Sewer lines not driven by gravity require special permission from UBC Utilities accompanied with an explanation, pump capacity (L/s) at operating head (kPa), a diagram showing pump curve and elevations which pump functions. CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  - 8 -  Figure 3.  Diagrammatic top-view representation of proposed sewer addition to supply Power House Bioreactor with constant supply of fresh wastewater. (Not to scale)  Gravity sewers are sized using the Manning’s Formula with an “n” value of 0.011 for PVC and 0.013 for concrete.  During peak flow, the depth should not exceed 50% with a minimum flow velocity of 0.6 m/s.  Minimum pipe size for industrial/research areas is 250 mm and a minimum of 150 mm size shall be used for connectors.  Regardless of pipe slope and capacity, downstream size shall be equal or larger diameter. No downsizing.  All service connections shall be installed with a manhole.  PVC piping is preferred for all piping under 450 mm. CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  - 9 -  Figure 4. Actual satellite top-view of proposed sewer addition site. (Google Earth, 2010) The minimum diameter of piping is required for S1, the gravity driven section, is 8.58 mm (Appendix A).  Peak wastewater flows vary greatly throughout the day, even as much as an eight to one difference (An, 1999). To account for these peak flows, and to have a uniform piping system with the existing one, a final pipe diameter of 300 mm is used. Although the pipe size is less than 450 mm, reinforced concrete will be used in section S1 and S3 to conform with the existing underground sewer lines. The exposed S2 section, which will run out of the ground over the Power House and back into the ground, will be made of insulated PVC piping to reduce temperature fluctuations caused by the climate. UBC (2009) also states that there must be a maintenance manhole at each branch connection; therefore two manholes will be necessary, one at each of the connecting points on the existing main sewer trunk. 4.2 Price Analysis of Materials Table 1 is a materials price breakdown based off of Hanson Pipe & Precast Corporation, and Northland Distributing & MFG Incorporated. From Google Earth 2010, the following CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  - 10 - measurements were deduced to calculate pipe costs; S1 = 64m, S2 = 55m (includes pipe running the height of the building and across the roof), & S3 = 61m (Figure 4). Table 1. Materials price breakdown for the proposed sewer addition to transport wastewater to the roof of the UBC Power House Item [Diameter in mm] Length/piece [m] Units Unit Price [$] Total [$] Reinforced Concrete Pipe [300 mm] 2.29 56 62.10 3477.60 Insulated PVC Pipe [300 mm] 0.305 182 35.80 a 6515.60 Concrete Connector [300 mm] - 2 247.90 495.80 PVC Connector [300 mm] - 6 189.50 1137.00 Concrete Elbow [300 mm] - 4 335.00 1340.00 Insulated PVC Elbow [300 mm] - 2 170.66 a 341.32 Insulated PVC Tee [300 mm] - 2 307.84 a 615.68 Maintenance Holes [1200mm] 2.0 b 2 1684.50 3369.00 TOTAL  256  $17,292.00 a Prices interpolated from smaller pipe sizes.    b Depth of Maintenance Hole.  4.3 Price Analysis of Construction Lim, Lee, and Park (2009) created equations to estimate the total construction cost of wastewater piping lines. A simplified version of their equations is used to calculate the proposed sewer addition to the UBC Power House.        CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  - 11 -   4.4 Pump Sizing To size a pump that is sufficient to push the wastewater across a 61 m sewer, up a slope of 0.066, then vertically 12 m to the roof of the Power House, while maintaining an exit velocity equal to that of the pipe velocity, it is necessary to determine the head loss across this path. The following equation is used to determine the required pump head needed to achieve this task (Finnemore & Franzini, 2002).   Using this equation, the pump head required to maintain the same average flow of 12.0 lps through the new addition is 17.0 m. Taking this into consideration, it is recommended to use a 4 inch submersible horizontal discharge sewage pump. The following is a particular model made by Barnes ® , which will perform close to optimum efficiency during average flow while still allowing operation at higher flows that are closer to the peak.   Figure 5.  Image of the recommended pump. Series: 4SE-L 4.5 – 15HP, 1750 RPM, 60Hz CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  - 12 -  Figure 6. Pump Curve for the Barnes ® Series: 4SE-L 4.5 – 15HP, 1750 RPM, 60Hz with the operating point highlighted in red, showing 50% efficiency. 4.5 Total Cost The electricity costs are calculated (Appendix A) based on the fact that the pump runs at 15 hp (11.19 kW). A total cost figure is calculated based on the materials, construction, pump requirement for the proposed sewer, and year round electricity to operate the pump. A final cost of approximately sixty-five thousand dollars is needed for the set up and operation of the pump (see Table 2 and 3). CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  - 13 - Table 2 & 3. Total cost breakdown including materials of pipe, labour, construction expenses, contractor’s overhead, contractor’s profit and pump. Parameters used in the study. Variable Cost [$] Percent of Cost [%]  Parameter Value Piping 9993.20 15.48  adl 2106.3 Materials 7298.80 11.30  bdl 16.326 Labour 29738.08 46.05  α 0.2 EXP 7946.26 12.31  β 0.05 OH 2383.88 3.69  γ 0.1 PRO 2032.33 3.15 Pump 2990.00 4.63 Electricity (per year) 2193.26 3.40 TOTAL $64,575.81 100% c  Price taken from a pump comparable in performance to the Barnes® Series: 4SE-L 4.5 – 15HP, 1750 RPM, 60 Hz  5.0 OPPORTUNITIES FOR FUTURE WORK Given that the cost of a PBR for UBC is prohibitive, it may be worth considering a raceway bioreactor.  Although this type of system requires more land, it can handle much greater volumes, and requires a lower capital expenditure. Algae metabolism is a complex topic, as discussed in Section 2, and Vancouver-based pilot scale studies are recommended to determine the optimal species of algae to use in a secondary wastewater effluent medium. Converti (2009) compares C. vulgaris and N. oculata at various temperatures and nitrogen concentrations and finds that both species have the highest yield at low NaNO3 concentrations. However, the lowest concentrations studied were 75 mg/L for N. oculata and 375 mg/L for C. vulgaris.  Lipid yields varied very little for N. oculata between 15°C and 25°C.  It is possible, therefore, that no additional heat would need to be supplied to the system designed by Christine Hung if N. oculata were used.  C. vulgaris showed the highest lipid yield at 25°C based on a study range of 25°C to 35°C.  Although at 25°C C. vulgaris had approximately double the maximum yield of N. oculata, determining whether C. vulgaris can be cultivated at temperatures below 25°C requires further research.  CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  - 14 - 6.0 CONCLUSION The aim of this paper is to provide a greater understanding of bioreactor processes, to shed some light on optimal algae species and lastly, to design and explore the feasibility of constructing a sewer system to supply the bioreactor with wastewater. In calculating the annual production of the bioreactor some discrepancies are found in Hung’s work. There is a 14.7% difference in the hydrocarbon production volume calculated by Hung (37 m 3 ) and the value calculated in this report (22.3 m 3 ). The projected annual income is $32,600, which is much lower than Hung’s value of $4.77-million. Between the three species studied, B. braunii, N. oculata and Scenedesmus, the latter performed the best, with an annual yield of 45.13 m 3  and annual revenue of $70,000. A sewer line design was proposed to supply the Power House with nutrient rich wastewater. The proposed design has a capital cost of $65,000 and an annual electricity cost of $2,200. The cost of the sewer line over a ten year period adds $8,700 to the $1.1-million annual instalment forecasted by Hung. The addition of a photo-bioreactor on the UBC Power House roof is therefore not considered feasible. Further research should be considered; including assessing the viability of a raceway pond and/or nutrient extraction operation using algae. Pilot tests should be carried out to determine the optimal algae species for flue gas capture in Vancouver’s climate using UBC’s wastewater effluent. CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  - 15 - 7.0 NOMENCLATURE PWWF = Peak Wet Weather Flow PDWF = Peak Dry Weather Flow EXP = construction expenses for piping OH = contractor’s overhead for piping PRO = contractor’s profits for piping DLS# = direct labour cost associated with section of piping adl = regression parameter for direct labour cost for piping bdl = regression parameter for direct labour cost for piping A = cross sectional area of pipe [m 2 ] lS# = length of pipe section α = coefficient for construction expenses β = coefficient for contractor’s overhead γ = coefficient for contractor’s profits hL = head loss hf = head loss due to friction he = head loss due to entrance and exit hb = head loss due to bends f con= friction factor for concrete piping f PVC = friction factor for PVC piping ke = exit loss coefficient kb = bend loss coefficient econ = absolute roughness for concrete pipe ePVC = absolute roughness for PVC pipe   CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  - 16 - 8.0 REFERENCES Alpin & Martin Consultants Ltd. Master Servicing Plan: Stormwater Management, Technical Report. Oct. 2001.  Aslan S, Kapdan IK. Batch kinetics of nitrogen and phosphorus removal from synthetic wastewater by algae. Ecological Engineering 2006;28(1):4–70.  Barrow C, Shahidi F. Marine nutraceuticals and functional foods. CRC Press, Taylor & Francis Group; 2008.  Barnes® (2009). Series 4SE-L Pump Catalog (Section 1D). Retrieved from www.cranepumps.com/downloadables/CATALOGS_OIPMs/BARNES/1D/BE1D-5.PDF  El-Hamouri, A.R., Vasel, J.L. (2003). Water Science and Technology, 48(2), 269-276  Finnemore, E.J. & Franzini, J.B. (2002). Fluid Mechanics: With Engineering Applications. New York, NY: McGraw-Hill.  Grant, M., Hill, G., Holbrook, C., Lymburner, P., McTavish, A., & Sundby, A. (2002). Water Management and Waste Water Treatment at the University of British Columbia: A Study for Sustainable Alternatives. An Undergraduate Honours Thesis, UBC Bachelor of Science in Environmental Science.  Grainger® (2010). Pump, Sewage/Trash, 15hp. Retrieved from http://www.grainger.com/Grainger/items/4YY41  Hanson Hieldberg Cement Group (2010). Hanson Pipe & Precast: 2010 Ontario Price List. Cambridge, ON: Hanson  Hydronic Heating Supplies (2003). Insul-Seal Price List. Retrieved from http://www.hydronicheatingsupplies.com/index.php?cPath=9_37  Hung, C. (2008) Design and feasibility analysis of a photobioreactor for Carbon Dioxide mitigation and energy recovery at UBC powerhouse. Undergraduate thesis.  Chemical and Biological Engineering Department. University of British Columbia.  Kadam KL. Power plant flue gas as a source of CO2 for Microalgae cultivation: economic impact of different process options. Energy Conversion and Management 1997;38(Suppl.):505–10.  Lim, S., Lee, H., Park, J.M. (2009). Life Cycle Cost Minimization of a Total Wastewater Treatment Network System. Industrial & Engineering Chemical Research, 48, 2965- 2971.  Mata, T.M., Martins, A.A., Caetano, N.,S., (2010). Microalgae for biodiesel production and other applications:  A review. Renewable and Sustainable Energy Reviews, 14, 217–232 CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  - 17 - Moody Diagram. Retrieved from http://webscripts.softpedia.com/screenshots/Moody-Diagram-18171.png  Ratchford, I.A.J., Fallowfield, H.J. (1991) Performance of a flat-plate, airlift reactor for the growth of high biomass algal cultures. Journal of Applied Phycology, 4, 1-9.  Reinhardt G, Rettenmaier N, Koppen S. How sustainable are biofuels for transportation? In: Bioenergy: challenges and opportunities. International conference and exhibition on bioenergy; 2008.  University of British Columbia (2004). North Campus Neighbourhood Plan. Vancouver, BC: UBC  Xin, L., Hu, H.Y., Ke, G., Ying-xue, S. (2010). Effects of different nitrogen and phosphorus concentrations on the growth, nutrient uptake, and lipid accumulation of a freshwater microalga Scenedesmus sp. Bioresource Technology. 101, 5494-5500. CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  A - 1        APPENDIX A  SAMPLE CALCULATIONS                            CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  A - 2 CALCULATIONS 1. Manning Equation to calculate minimum pipe diameter for gravity driven section, S1.  With 50% depth as outlined by UBC Technical Guidelines, therefore Pw= P/2  Velocity equals a minimum of 0.6 m/s as outlined by UBC Technical Guidelines      2. Peak Wet Weather Flow (PWWF)  Peak Dry Water Flow is taken as the peak design flow of the “N-158” manhole from the 2012 Sanitary Model Data (Alpin & Martin, 2001)  Infiltration is taken from the same data set    3. Pump head required to lift water through S3 and onto the roof of the Power House(½ S2) maintaining the same velocity of 12.0 lps as in average flow (Alpin & Martin, 2001) CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  A - 3    The wastewater is assumed to have a density of 1150 kg/m3  V = 0.16977 m/s (based off of average flow through main trunk & D=300mm)  econ = 0.0015 mm; ePVC  ≈ 0; all k values (Finnemore & Franzini, 2002);  vsewage  = 1.1555e-06 m2/s. Assumed to be the same as water at 15ºC.  fcon  = fPVC  ≈ 1.57 (Moody Diagram in Appendix B)    4. Electricity costs for operating the pump year round  Electricity costs taken extrapolated from data: Vancouver o 7 kW/month = $82.64 o 20 kW/month = $393.31     CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  A - 4  Value  Description X (kg/m3) 6  Biomass concentration V_L (m3) 0.232  Liquid volume in bioreactor N 505  Number of bioreactors in system Y_CO2 / Y_biomass 1.88  Mass CO2 consumed per unit biomass produced Eta 64.00%  Percent of lipids produced which are converted to biodiesel rho_HC (kg/m^3) 667  Mass density of HC C_biodiesel ($/litre) 1.304  Value per litre of biodiesel C_CO2 ($/ton) 25  Value per ton of CO2 in carbon credits The parameters used in Hung, 2008 were left unchanged.  The specific growth rate was adjusted based on the algae species of interest.   Value  Equation/Source Botryococcus braunii    Specific growth rate mu (1/s) 3.48E-06  Hung 2006 Lipid content 30.00%   Biomass production rate (kg/s/reactor) 4.84E-06   Total biomass produced per year (kg) 77199  Total HC produced (m^3) 22.22  Value of HC ($) $28,977.89   CO2 captured (tons) 145.13  Value of CO2 credits ($) $3,628.37      Total revenue $32,606.26      Chlorella vulgaris    Specific growth rate mu (1/s) 1.00E-05  Ratchford and Fallowfield, 1992 Lipid content 10.00%   Biomass production rate (kg/s/reactor) 1.39E-05   Total biomass produced per year (kg) 221837                  Lbiomass XVQ               yr days day s NQQ biomasstotal 25.36586400 HC total LipidsQHC  )(%  biomass CO totalCO Y Y QQ 2 2  Lbiomass XVQ               yr days day s NQQ biomasstotal 25.36586400 HC total LipidsQHC  )(%  CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  A - 5 Total HC produced (m^3) 21.29 Value of HC ($) $27,756.60   CO2 captured (tons) 417.05  Value of CO2 credits ($) $10,426.35      Total revenue $38,182.96  Nanochloropsis oculata    Specific growth rate mu (1/s) 6.94E-06  James and Al-Khars, 1989 Lipid content 10.00%   Biomass production rate (kg/s/reactor) 9.66E-06   Total biomass produced per year (kg) 153955  Total HC produced (m^3) 14.77  Value of HC ($) $19,263.08   CO2 captured (tons) 289.44  Value of CO2 credits ($) $7,235.89      Total revenue $26,498.97      Scenedesmus sp.    Specific growth rate mu (1/s) 1.06E-05  Ratchford and Fallowfield, 1992 Lipid content 20.00%   Biomass production rate (kg/s/reactor) 1.48E-05   Total biomass produced per year (kg) 235148  Total HC produced (m^3) 45.13  Value of HC ($) $58,844.00   CO2 captured (tons) 442.08  Value of CO2 credits ($) $11,051.93      Total revenue $69,895.93  biomass CO totalCO Y Y QQ 2 2  Lbiomass XVQ               yr days day s NQQ biomasstotal 25.36586400 HC total LipidsQHC  )(%  biomass CO totalCO Y Y QQ 2 2  Lbiomass XVQ               yr days day s NQQ biomasstotal 25.36586400 HC total LipidsQHC  )(%  biomass CO totalCO Y Y QQ 2 2  CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  B - 1         APPENDIX B  FIGURES & DATA                           CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  B - 2   CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  B - 3  CHBE 484 ALGAE BIOREACTOR SYSTEM   APRIL 2010 Chen, Deviato, & Kras  B - 4  


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