Name: comparison of scale in a photosynthetic reactor system for algal remediation of wastewater
Uploaded: 2017-03-06T14:00:00
Description: Watch this Scientific Journal Video about Comparison of Scale in a Photosynthetic Reactor System for Algal Remediation of Wastewater at JoVE.com

The authors would like to thank the Sandtown Landfill in Felton, DE for sharing their knowledge and leachate.

1. System Setup
Note: A &#39;paired system&#39; refers to one aquarium tank and one raceway pond, run in parallel.
<ol>
	<li>For one paired system, use one 100 L aquaria tanks (AT), with an overhead mixer for the small-scale vessel, and one 1,000 L raceway pond (RWP), with a paddle wheel mixer for the large-scale vessel. Vessels used in this system are pictured in Figure 1.</li>
	<li>Inoculate all vessels with the same algae culture. Use a high density of the inoculation, resulting in a final de...

<ol>
	<li>Janssen, M., Tramper, J., Mur, L. R., Wijffels, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enclosed+outdoor+photobioreactors:+light+regime,+photosynthetic+efficiency,+scale-up,+and+future+prospects.">Enclosed outdoor photobioreactors: light regime, photosynthetic efficiency, scale-up, and future prospects.</a> Biotechnol. Bioeng. 81 (2), 193-210 (2003).</li><li>Takors, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Scale-up+of+microbial+processes:+impacts,+tools+and+open+questions.">Scale-up of microbial processes: impacts, tools and open questions.</a> J. Biotechnol. 160 (1), 3-9 (2012).</li><li>Sauer, M., Porro, D., Mattanovich, D., Branduardi, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microbial+production+of+organic+acids:+expanding+the+markets.">Microbial production of organic acids: expanding the markets.</a> Trends in Biotechnol. 26 (2), 100-108 (2008).</li><li>Junker, B. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Scale-up+methodologies+for+Escherichia+coli+and+yeast+fermentation+processes.">Scale-up methodologies for Escherichia coli and yeast fermentation processes.</a> J. Biosci. Bioeng. 97 (6), 347-364 (2004).</li><li>Brennan, L., Owende, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biofuels+from+microalgae-a+review+of+technologies+for+production,+processing,+and+extractions+of+biofuels+and+co-products.">Biofuels from microalgae-a review of technologies for production, processing, and extractions of biofuels and co-products.</a> Renewable Sustainable Energy Rev. 14 (2), 557-577 (2010).</li><li>Van Den Hende, S., Beelen, V., Bore, G., Boon, N., Vervaeren, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Up-scaling+aquaculture+wastewater+treatment+by+microalgal+bacterial+flocs:+from+lab+reactors+to+an+outdoor+raceway+pond.">Up-scaling aquaculture wastewater treatment by microalgal bacterial flocs: from lab reactors to an outdoor raceway pond.</a> Bioresour. Technol. 159, 342-354 (2014).</li><li>Hewitt, C. J., Nienow, A. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Scale-Up+of+Microbial+Batch+and+Fed-Batch+Fermentation+Processes.">The Scale-Up of Microbial Batch and Fed-Batch Fermentation Processes.</a> Adv Appl Microbiol. 62, 105-135 (2007).</li><li>Downton, W., Bishop, D., Larkum, A., Osmond, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oxygen+Inhibition+of+Photosynthetic+Oxygen+Evolution+in+Marine+Plants.">Oxygen Inhibition of Photosynthetic Oxygen Evolution in Marine Plants.</a> Funct Plant Biol. 3 (1), 73-79 (1976).</li><li>Pholchan, M. K., Baptista, J. d. C., Davenport, R. J., Curtis, T. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Systematic+study+of+the+effect+of+operating+variables+on+reactor+performance+and+microbial+diversity+in+laboratory-scale+activated+sludge+reactors.">Systematic study of the effect of operating variables on reactor performance and microbial diversity in laboratory-scale activated sludge reactors.</a> Water Res. 44 (5), 1341-1352 (2010).</li><li>Richmond, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Handbook of microalgal culture: biotechnology and applied phycology. , (2008).</li><li>Clesceri, L. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Standard Methods for the Examination of Water and Wastewater. , (1998).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Statistics for Macintosh v.23.0. , (2015).</li><li>Devore, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Probability and Statistics for Engineering and the Sciences. , (2015).</li><li>Sniffen, K. D., Sales, C. M., Olson, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nitrogen+removal+from+raw+landfill+leachate+by+an+algae-bacteria+consortium.">Nitrogen removal from raw landfill leachate by an algae-bacteria consortium.</a> Water Sci. Technol. 73 (3), 479-485 (2015).</li><li>Paerl, H. W., Fulton, R., Moisander, P. H., Dyble, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Harmful+freshwater+algal+blooms,+with+an+emphasis+on+cyanobacteria.">Harmful freshwater algal blooms, with an emphasis on cyanobacteria.</a> Scientific World J. 1, 76-113 (2001).</li><li>Abeliovich, A., Azov, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toxicity+of+Ammonia+to+Algae+in+Sewage+Oxidation+Ponds.">Toxicity of Ammonia to Algae in Sewage Oxidation Ponds.</a> Appl. Environ. Microbiol. 31 (6), 801-806 (1976).</li><li>Azov, Y., Goldman, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Free+ammonia+inhibition+of+algal+photosynthesis+in+intensive+cultures.">Free ammonia inhibition of algal photosynthesis in intensive cultures.</a> Appl. Environ. Microbiol. 43 (4), 735-739 (1982).</li><li>Adamsson, M., Dave, G., Forsberg, L., Guterstam, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toxicity+identification+evaluation+of+ammonia,+nitrite+and+heavy+metals+at+the+Stensund+Wastewater+Aquaculture+Plant,+Sweden.">Toxicity identification evaluation of ammonia, nitrite and heavy metals at the Stensund Wastewater Aquaculture Plant, Sweden.</a> Water Sci. Technol. 38 (3), 151-157 (1998).</li><li>Quinn, J. C., Davis, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+potentials+and+challenges+of+algae+based+biofuels:+a+review+of+the+techno-economic,+life+cycle,+and+resource+assessment+modeling.">The potentials and challenges of algae based biofuels: a review of the techno-economic, life cycle, and resource assessment modeling.</a> Bioresour. Technol. 184, 444-452 (2015).</li><li>Liu, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pilot-scale+data+provide+enhanced+estimates+of+the+life+cycle+energy+and+emissions+profile+of+algae+biofuels+produced+via+hydrothermal+liquefaction.">Pilot-scale data provide enhanced estimates of the life cycle energy and emissions profile of algae biofuels produced via hydrothermal liquefaction.</a> Bioresour. Technol. 148, 163-171 (2013).</li><li>Van Den Hende, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Treatment+of+industrial+wastewaters+by+microalgal+bacterial+flocs+in+sequencing+batch+reactors.">Treatment of industrial wastewaters by microalgal bacterial flocs in sequencing batch reactors.</a> Bioresour. Technol. 161, 245-254 (2014).</li><li>Rawat, I., Kumar, R. R., Mutanda, T., Bux, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biodiesel+from+microalgae:+A+critical+evaluation+from+laboratory+to+large+scale+production.">Biodiesel from microalgae: A critical evaluation from laboratory to large scale production.</a> Appl. Energy. 103, 444-467 (2013).</li><li>Cloern, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+relative+importance+of+light+and+nutrient+limitation+of+phytoplankton+growth:+a+simple+index+of+coastal+ecosystem+sensitivity+to+nutrient+enrichment.">The relative importance of light and nutrient limitation of phytoplankton growth: a simple index of coastal ecosystem sensitivity to nutrient enrichment.</a> Aquat Ecol. 33 (1), 3-15 (1999).</li></ol>

System performance:
Over the course of an 8-week study, the productivity of the small- and large-scale vessels in a system were compared. In this study nitrogen and ammonia removal rates and biomass growth rates were used as measures of productivity of the treatment system. The system was operated as a semi-batch reactor, where each week was operated under discrete conditions. Representative results account for the first 8 weeks of system operation, however a full study would extend for much long...

Translation of bench-scale data to larger scale applications is a key step in the commercialization of bioprocesses. Production efficiencies in small-scale reactor systems, particularly those focusing on the use of microorganisms, have been shown to consistently over predict efficiencies occurring in commercial-scale systems 1,2,3,4. Challenges also exist in scaling up photosynthetic cultivation of algae and cyanobacteria from the laboratory scale to larger systems for the purpose of manufacturing high-value products, such as cosmetics and pharmaceuticals, for production of biofuels, and for the treatment of wastewater. The demand for large-scale algal biomass production is growing with the emerging industry for algae in biofuel, pharmaceuticals/nutraceuticals, and livestock feed 5. The methodology described in this manuscript aims to evaluate the influence of increasing scale of a photosynthetic reactor system on biomass growth rate and nutrient removal. The system presented here uses algae to remediate landfill leachate wastewater but can be adapted for a variety of applications.
Production efficiencies of large scale systems are often predicted using smaller scale experiments; however, several factors must be considered to determine the accuracy of these predictions, as scale has been shown to affect the performance of bioprocesses. For example, Junker (2004) presented results from a comparison of eight different-sized fermentation reactors, ranging from 30 L to 19,000 L, which showed that actual productivity at pilot- or commercial-scales was almost always lower than the values predicted using small-scale studies 4. Inequalities in vessel dimension, mixing power, agitation type, nutrient quality, and gas transfer were predicted to be the major causes for the decreased productivity 4. Similarly, it has been shown in algae growth reactors that biomass growth and biomass related products are nearly always reduced when scale is increased 6.
Biological, physical, and chemical factors change with the size of a reactor, with many of these factors influencing microbial activity at small scales differently than at larger scales 2,7. Since most full-scale systems for algae, such as raceway ponds, exist outdoors, one biological factor to consider is that microbial species and bacteriophages can be introduced from the surrounding environment, which may alter the microbial species present and thus the microbial function of the system. The activity of the microbial community will also be sensitive to environmental factors, such as light and temperature. Mass transfers of gasses and fluid motion are examples of physical factors that are influenced in the scale up of microbial processes. Achieving ideal mixing in small reactors is easy; however, with increasing scale, it becomes a challenge to engineer ideal-mixing conditions. At larger scales, reactors are more likely to have dead zones, non-ideal mixing, and reduced efficiencies in mass transfer 2. Since algae are photosynthetic organisms, commercial growth must account for changes in light exposure due to changes in water depth and surface area when increasing volume. High biomass density and/or low mass transfer rates can cause decreased CO2 concentrations and increased O2 concentrations, both of which may result in inhibition of biomass growth 8. Chemical factors in an algae growth system are driven by pH dynamics of the aquatic environment 2, which is consequently affected by changes in pH buffering compounds such as dissolved CO2 and carbonate species. These factors are compounded by complex interactions among the biological, physical, and chemical factors, often in unpredictable ways 9.
This study presents a paired reactor system designed to regulate and compare growth conditions in vessels of two different scales. The experimental protocol focuses on quantifying leachate treatment and algae growth; however, it could be adapted to monitor other metrics such as changes in the microbial community over time or the CO2 sequestration potential of algae. The protocol presented here is designed to evaluate the effect of scale on algal growth and nitrogen removal in a leachate treatment system.

<table border="0" cellpadding="0" cellspacing="0" width="1148">
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	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Aquarium Tank</td>
			<td style="width:135px;"></td>
			<td style="width:119px;"></td>
			<td style="width:612px;">Any 100+L aquarium tank with optically clear glass can be used</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:283px;">RW 3.5</td>
			<td style="width:135px;">MicroBio Engineering</td>
			<td style="width:119px;"></td>
			<td>Raceway Pond</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Eurostar 100 digital</td>
			<td style="width:135px;">IKA</td>
			<td style="width:119px;">4238101</td>
			<td style="width:612px;">Overhead mixers</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Leachate</td>
			<td style="width:135px;">Sandtown Landfill</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Sampling Bottles</td>
			<td style="width:135px;">Nalgene</td>
			<td style="width:119px;"></td>
			<td>Plastic or glass, lab grade, 125-200mL&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Transfer Pumps</td>
			<td style="width:135px;"></td>
			<td style="width:119px;"></td>
			<td>Garden type pump with drinking water quality hoses will be suitable</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">AmVer Salicylate Test &#39;N Tube</td>
			<td style="width:135px;">Hach</td>
			<td style="width:119px;">2606945</td>
			<td>High Range Ammonia Tests</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">NitraVer X Nitrogen - Nitrate Reagent Set&#160;</td>
			<td style="width:135px;">Hach</td>
			<td style="width:119px;">2605345</td>
			<td>High Range Nitrate Tests</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">NitriVer 2 Nitrite Reagent Powder Pillows</td>
			<td style="width:135px;">Hach</td>
			<td style="width:119px;">2107569</td>
			<td>High Range Nitrite Tests</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Hach DR2400 Spectrophotmeter</td>
			<td style="width:135px;">Hach</td>
			<td style="width:119px;"></td>
			<td>The DR2400 was discontinued, but any DR series Hach spectrophotometer can be used in this application.&#160;</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:283px;">EMD Microbiological Analysis Membrane Filters</td>
			<td style="width:135px;">Millipore</td>
			<td style="width:119px;">HAWG047S6</td>
			<td style="width:612px;">0.45&#181;m filters&#160;</td>
		</tr>
	</tbody>
</table>

comparison of scale in a photosynthetic reactor system for algal remediation of wastewater

An experimental methodology is presented to compare the performance of two different sized reactors designed for wastewater treatment. In this study, ammonia removal, nitrogen removal and algal growth are compared over an 8-week period in paired sets of small (100 L) and large (1,000 L) reactors designed for algal remediation of landfill wastewater. Contents of the small and large scale reactors were mixed before the beginning of each weekly testing interval to maintain equivalent initial conditions across the two scales. System characteristics, including surface area to volume ratio, retention time, biomass density, and wastewater feed concentrations, can be adjusted to better equalize conditions occurring at both scales. During the short 8-week representative time period, starting ammonia and total nitrogen concentrations ranged from 3.1-14 mg NH3-N/L, and 8.1-20.1 mg N/L, respectively. The performance of the treatment system was evaluated based on its ability to remove ammonia and total nitrogen and to produce algal biomass. Mean &#177; standard deviation of ammonia removal, total nitrogen removal and biomass growth rates were 0.95&#177;0.3 mg NH3-N/L/day, 0.89&#177;0.3 mg N/L/day, and 0.02&#177;0.03 g biomass/L/day, respectively. All vessels showed a positive relationship between the initial ammonia concentration and ammonia removal rate (R2=0.76). Comparison of process efficiencies and production values measured in reactors of different scale may be useful in determining if lab-scale experimental data is appropriate for prediction of commercial-scale production values.

The aim of this study is to compare the biomass growth and nutrient removal capabilities of algal cultures grown in small- and large-scale reactors. This study uses two paired systems, referred to as System 1 and System 2, to duplicate its findings. These representative results are from an 8-week period, February through April, 2016. The first raceway pond was inoculated with algae originally sourced from an outdoor pond in Philadelphia, PA 14. This culture was gro...

Watch this Scientific Journal Video about Comparison of Scale in a Photosynthetic Reactor System for Algal Remediation of Wastewater at JoVE.com

Comparison of Scale in a Photosynthetic Reactor System for Algal Remediation of Wastewater

An experimental methodology is presented to compare the performance of small (100 L) and large (1,000 L) scale reactors designed for algae remediation of landfill wastewater. System characteristics, including surface area to volume ratio, retention time, biomass density, and wastewater feed concentrations, can be adjusted based on application.

An experimental methodology is presented to compare the performance of two different sized reactors designed for wastewater treatment. In this study, ...

The overall goal of this procedure is to evaluate the effect of scale on algal growth and nitrogen removal in a leachate treatment system. This method can help determine how increasing the scale of a system will impact the treatment efficiency. The main advantage of this technique is that it can be adapted for a variety of microbial and wastewater treatment systems.For this protocol, a paired system refers to one 100 liter aquarium tank and one 1, 000 liter raceway pond run in parallel. Start with a high density inoculum, which may take weeks to months to grow enough algae for. Inoculate all vessels with the same algae culture, ensuring that the final density is no less than 0.1 grams per liter once diluted to the full volume in the tank or pond.Untreated landfill leachate serves as the nutrient source for this system. Use leachate taken from a landfill that accepts primarily domestic waste and has low levels of toxins. The amount of leachate used in each tank or pond can vary depending on the strength of the wastewater.Start the aquarium tank with one liter of leachate in 59 liters of water for a 60 liter working volume. Likewise, start the raceway pond with 10 liters of leachate in 590 liters of water for a 600 liter working volume. Week to week, operate the aquarium tank and raceway pond as semi-batch reactors with hydraulic retention times of three weeks.Monitor environmental conditions, such as air temperature and solar radiation, using a commercial weather station. Also monitor tank or pond conditions, such as water temperature, pH, and dissolved oxygen, using commercial probes and a data logger. At the beginning of each week, take a 125 milliliter sample from each vessel to be tested for biomass density, as well as ammonia-N, nitrate-N, and nitrite-N.Measure the biomass by a standard total suspended solids protocol using 0.45 micron filters. After weighing the filter paper, filter 20 to 40 milliliters of sample using a vacuum filtration system. Dry the biomass and filter paper in an oven at 105 degrees Celsius for one hour.After drying, calculate the biomass density. Next, measure ammonia, nitrate, and nitrite using a spectrophotometer and commercial method kits according to the manufacturer's protocol. After one week, take 125 milliliter samples from each vessel and analyze the samples as before.This is the end of the first week. To prepare for the next week's cycle, pump the entire volume of the aquarium tank into the raceway pond. Remove 1/3 of the volume from the raceway pond.Replace the volume removed with water and untreated leachate. Then, transfer approximately 60 liters from the raceway pond back into the aquarium tank. This ensures that the aquarium tank and the raceway pond are starting with the same nutrient and biological conditions each week.In this study, two paired systems were used, referred to as system one and system two, to duplicate the findings. Ammonia removal rate, total nitrogen removal rate, and biomass growth rate were used as metrics to evaluate the treatment system. The rates from system one and system two are shown here for the representative study period.Data from all vessels over the representative study period showed that ammonia removal trended positively with increasing starting ammonia concentration. Once the system is up and running, reactor parameters, such as biomass density, length of time between mixing, working volume, retention time, and the amount of wastewater added, can be adjusted to better test a customized system. Ultimately, results from this procedure can be used to inform feasibility studies of full scale treatment processes.For example, the effect of scale on important reactor parameters, such as growth rate and nutrient removal, can be used to verify the accuracy of input data used to simulate full scale production processes and lifecycle assessments and technoeconomic analyses. This is a versatile methodology which can be adapted to study the treatment of a variety of wastewaters.

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