Frequently Asked Questions
Q: Do you have tours? Can I schedule a visit?
A: Yes, we are available to give scheduled tours to individuals interested in the technology, though our schedule is dynamic and often full. Availability is limited. Please include your request in an e-mail to firstname.lastname@example.org with your tour needs.
Q: I’m working on algae-related projects, and I’d like to talk with someone at AVS about collaborations – how can I get in touch with the right person?
A: The best way to start is to tell us about your project and your interests. Go to “Become a Collaborator” under the “Contact Us” link. The more detailed you can be, the better we will be able to respond to your inquiry.
Q: I was wondering if your systems are being used as algae mitigation in public waterways, to stop the cycle of nutrients producing harmful algae blooms.
A: We have worked on just such a project for Ohio’s Grand Lake St. Marys testing some of our remediation hypothesis & technologies, and we’re in discussions with the Natural Resource Conservation Service, EPA, and other agencies who are interested in algal remediation. We believe that our low-energy breakthroughs will make on-lake and upstream remediation economically feasible.
Q: Do your systems have anything to do with algae in wastewater treatment?
A: Yes, algae has been part of wastewater treatment for decades, but only in limited applications. We believe our low-energy solutions should lead to widespread application of algal remediation for wastewater treatment in municipal, commercial, and environmental settings. Also the SLS machine has the ability to remove micro-solids from dilute solutions at very low energy, making the capture of co-products from waste streams economically viable.
Q: What type of growth systems have you worked with – closed systems, open ponds, both?
A: We have been focused on covered growth systems initially, but as part of our ARPA-E project, we will expand to cultivated open-pond systems, and even natural-growth open water systems (lakes and rivers). We think that the great leap in energy cost reduction that our SLS brings to algae harvesting opens the door to making open-air algal growth commercially viable.
Q: What type of algae do you recommend growing?
A: There are about 30,000 named species of algae, and there are a lot of variables that make some species better than others, depending on growth conditions, environment, and nutrient optimization. Microalgae have the best growth potential, and the class known as “diatoms” tends to be highest in lipid content. We have many partners, each of which has worked with their own portfolio of species. Please see our resources page for more information on growing algae.
Q: What is the pore size for the membrane?
A: We use different (pore size) membranes, based on specific processing needs and have a portfolio of them ranging from 1-200 micron.
Q: What sizes are used for most typical algae species?
A: We want to use the largest pore size possible while continuing to capture algae. If we have mixed species, we size the membranes according to the smallest species found in the mixture.
Q: What is the gap between the belts? (Screen belt, Cap belt).
A: There’s no gap – we need the cap belt to touch the membrane belt to break the menisci of the water molecules. That’s how we create the capillary effect that takes advantage of the intermolecular forces in the water. Our process taps into those tiny electrical charges, to supply the energy to move the water away from the algae, rather than us having to generate electricity to run a centrifuge.
Q: Do you use chemicals (to aid the water separation?).
A: Rarely but, depending on the material being harvested, the option of adding chemicals to facilitate the flow of water is consistent with our technology. Most often, utilizing our RAC technology will allow for a higher concentration of algae which ensures more efficient dewatering.
Q: When will the SLS system be commercially available?
A: The purpose of the ARPA-E project is to create and sustain future jobs while commercializing an energy reducing technology Production on the SLS Pilot Model began Q2’10. This model and our SLS Lab Model are currently available for sale.
Q: What is the moisture content of the algae when it leaves the SLS?
A: The SLS can dewater algae up to 50% depending on the concentration, size, and water makeup. Then, with added drying capability (heat, fans, tunnels, etc.), the algae can be dried to 97%+ solids in process.
Q: What concentrations of algae can the SLS process?
A: We have been working with concentrations that are between 2 grams/liter and 6 grams/liter. Higher concentrations are easier to capture. For applications where the solutions are more dilute we are creating technologies for pre-concentrating algae without the use of flocculants.
Q: What types of algae have been harvested (micro, macro and monoculture, multi-species)?
A: We have been most successful at harvesting several distinctly different kinds of micro-algae: Chlorella Vulgaris, Botryococcus Braunii and Euglena Gracilis, and Scenedesmus Dimorphus. We have been able to harvest Chlorella Vulgaris, which is about 5 – 10 microns in size. We have tested some nano-algae and have had some fine successes when used in combination with our RAC or comparable agglomeration technology.
Q: Can the SLS be used to dewater materials other than algae?
A: Yes, our SLS system has successfully dewatered over 16 species of algae, duckweed, coal fines, 1 micron plant starch, 10 micron plant protein, rice gluten, fungi, and a host of other materials. Please see www.altere.com for more information on these other materials. In addition to the low-energy use, the SLS does not pressurize the membrane. It doesn’t squeeze nutrients out of food with the water, letting food processors dewater food and keep the higher nutrient value intact.
Q: How hard is it to open the SLS to clean or change the membrane (screen, belt)?
A: For both the filter and absorbent belt, we’re targeting 1% of operating expense for belt replacement. The frequency and replacement cost will depend on the material. It is not difficult to change belts, and they can be cleaned using normal household cleaning agents; however, our goals are to minimize cleaning and changing belts while maximizing their life cycle.
Q: What type of water has been tested (fresh water, salt water, brine) with the AVS SLS?
A: We have not tested the harvesting of salt water species in depth, but do not believe this to be of significant concern. Additionally, we have taken steps to address issues such as the effect of salt on metals and salt accumulation on belts. In-line “belt-rinse” systems have been made available to ensure that the unit functions at maximum efficiency over time, regardless of effluent running on the machine.
Q: What are your plans or terms for licensing your technology?
A: Please take the opportunity to contact us directly regarding these licensing questions, and we will discuss the multitude of options we can offer.
Q: What is the required electrical supply for the system? (Volts, Amperes, Watts, frequency, phase)
A: The SLS can be adapted to most electrical supply scenarios. A step transformer can be implemented to accommodate almost any voltage or frequency. The SLS Pilot Model is designed to operate using 120VAC, 15A, 60Hz. The combined power consumption of the belt drive and optional pump is approximately 40W. The optional drying unit is not considered as a factor in overall power consumption as we believe that waste heat from other processes may be implemented when the unit is properly co-located. Also needed for wet material removal is pressurized air available at 100 PSI.
Q: Is the AVS harvester suitable for all sizes of algae?
A: Our current filter membranes are in range from 7-700um. We have been able to dewater very small algae before by using our RAC material for concentration of the algae. This has proven successful in the past on such strains as Nanochloropsis.
Q: What is the throughput of the SLS unit?
A: The throughput of the SLS units depend on a multitude of different factors including species size, concentration, desired solids%, and more. We suggest that you contact us and attach a Lab Services form indicating what services you would like performed to understand the viability of your algae on our systems, as well as learn a host of different important factors concerning your culture.
Q: Is open-water harvesting on natural lakes economically viable?
A: Since our breakthroughs with the SLS and the RAC we’ve totally changed our thinking. There’s still a long way to go to prove that it’s going to be economically viable, but we’ve come so far that we’re ready to start pulling algae from lakes, to define the baseline, and determine how we will improve efficiencies to make it viable.