Grantee Research Project Results
Final Report: Utilization of Byproducts from a Solid Waste Landfill for the Sustainable Production of Algae Biodiesel
EPA Grant Number: SU835078Title: Utilization of Byproducts from a Solid Waste Landfill for the Sustainable Production of Algae Biodiesel
Investigators: Powers, Susan E. , Twiss, Michael R. , Angerosa, Jordan , Jamie Bates, William Armington , Boothroyd, Jeffrey , Engel, Holly , Fain, Samuel , Greenwood, Hannah , Grunert, Mark , Hanczyk, Daniel , Hughes, Aaron , Isabell, Ashley , Jerabeck, Allen , Kring, Stefanie , LaPan, Kristopher , Lawson, Kathryn , Lea, Nuttapong , Maciuba, Mitchell , Parmelee, Bethann , Pawlowski, Gabrielle , Pesante, Joseph , Rieder, Daniel , Yijia, Zhao , Sawyer, Rick
Institution: Clarkson University
EPA Project Officer: Hahn, Intaek
Phase: I
Project Period: August 15, 2011 through August 14, 2012
Project Amount: $15,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2011) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Air Quality , P3 Awards , Sustainable and Healthy Communities
Objective:
Our goal is to assess the feasibility of an algal biodiesel production facility at the Development Authority of the North Country (DANC) solid waste management facility in Rodman, NY. Because microalgae can be cultivated for high biomass production rates and high oil content, algae have the potential to displace other biodiesel feedstocks. Algal biodiesel production does not require the use of arable land, and thus algal biodiesel does not fall into the “food versus fuel” conflict that surrounds other feedstocks. The algae can be cultivated at the DANC facility using waste products. Nutrient-rich leachate from the solid waste landfill and waste heat from the onsite landfill gas to energy (LFGTE) plant will be used to grown the algae that provide lipid for biodiesel production.
By producing approximately 20,000 gal/yr of biodiesel and employing a B20 mix (20% biodiesel, 80% petroleum diesel) a portion of DANC’s current demand for petroleum diesel used for vehicles and heavy equipment could be displaced. The DANC facility is located in a rural, economically depressed region. The addition of an algal biodiesel production facility would not only benefit DANC financially, it would help to create jobs in the region and provide an opportunity for regional educational outreach about sustainability and sustainable industrial practices.
The project objectives were completed by an interdisciplinary team of Clarkson University students who worked together over the course of the 2011-2012 academic year. Laboratory scale experiments were performed to confirm that algal lipid can indeed be produced using waste products from the DANC facility. A mathematical model was created for the process and used to develop business and engineering plans and assess the lifecycle environmental impacts for a full scale process.
Summary/Accomplishments (Outputs/Outcomes):
Laboratory Scale Proof of Concept: In order to develop plans for a full scale algal biodiesel production process, laboratory scale experiments were completed to determine how best to optimize each step of the final design. The relevant findings of these laboratory experiments are detailed below.
Leachate Characterization: The landfill leachate from the DANC facility was characterized to quantify its quality as a growth medium. The leachate was determined to be neutral (pH 7.2) and contain abundant nutrients essential for algae growth. The presence of toxins, such as heavy metals and grease, in the leachate that could potentially hinder algae growth prompted tests to purify the leachate.
Bioreactor: Several laboratory scale bioreactor experiments were completed in order to quantify the growth characteristics of the algae species Chlorella protothecoides on landfill leachate. Two 14-day experiments were conducted to examine the impact that various levels of light intensity, leachate concentration, and leachate pretreatment had on growth characteristics of the algae. From these experiments it was determined that the growth rates of algae cultivated in 10% untreated leachate at a low light level (100 μmol photons/m2·s) are best (growth rates -- 0.13 d-1, 120 mg/L algae (dry weight), 38% lipid).
Processing Algae for Lipid Extraction: The water content of the cultivated algae must be reduced to 5% and cell walls must be broken before lipids can be extracted. Centrifuging was selected as the most effective means of dewatering the algae in a feasible period of time with relatively low energy requirements. Lipid extraction using bead beating to break the algae cells and a hexane isopropanol solvent mixture to remove the algae lipids proved more efficient at recovering lipids than ultrasonication at the laboratory scale.
Biodiesel Production: Due to the limited supply of clean water at the DANC site, a cost-efficient method of washing the algal biodiesel to make it clean and useable needed to be determined. The Purolite PD206 dry washing method was selected.
Full-Scale Process: To develop a feasible full-scale process that would consider factors such as the available waste heat from the LFGTE plant, limited availability of water, cold climate, and fuel needs, we employed a mathematical model to help optimize the design using quantitative factors from the laboratory scale testing as inputs. The target goal was to replace 20% of DANC’s yearly fuel supply with algal biodiesel.
The process of algal biodiesel production was divided into four large components: the growth and harvesting processes, the extraction of the algal lipid, the transesterification or conversion into biodiesel, and the purification of the biodiesel for integration into the facility’s fuel use. Each of these components has a number of sub-processes. The flow of these processes is shown in Figure 1.
Figure 1: Full-Scale Process
Growth and harvesting of the algae will start in an indoor, covered, cascading basin system that mimics a plug flow reactor. Residence time of each basin will be 1 day and the overall design will allow for the growth of large batches with few evaporative losses and less hazard to workers by the leachate. This basin system will be operated under a 24-hr constant light cycle, using energy efficient LED lighting. The cascading system will minimize building area and utilize gravity to transfer the media. Carbon dioxide from the LFGTE system will be bubbled through the basins to mix the slurry and act as a carbon source for the algae’s photosynthetic processes. Reactor output will feed into a continuous centrifuge to decrease the slurry’s water content to 65-70% water by weight and then dried in a convection drying oven to reduce water content to 5% by weight. Most of the water recovered through these dewatering processes will be used to maintain the growth medium for the algae in the reactor.
Lipid extraction from the dried algae meal will be done through a combination of mechanical means and solvent extraction. To convert the algae lipids into a diesel-engine compatible fuel, the lipids will undergo transesterification and dry washing to remove impurities.
The total building size for the full-scale system was estimated based on equipment dimensions, storage requirements, sizing of the bioreactor, logistical area, and walking space. The construction cost was estimated to be $2.1 million for the 20,500 ft2 building.
P3 Principles:
Environmental, social, and business assessments were completed to identify and quantify the positive and negative impacts of the of the proposed algal biodiesel facility and determine how the principles of sustainability factor into the project.
People: Socially, the creation of an algal biodiesel facility at the DANC site presents an opportunity for regional educational outreach on the principles of sustainability, potentially enhancing local high school science curricula. The algal biodiesel facility also addresses some community concerns about the DANC facility by reducing truck traffic associated with the shipment of leachate and onsite diesel emissions. It furthermore will increase the quality of life in the region by creating new jobs.
Prosperity: The local economy will benefit from this facility through the creation of three new jobs, totaling in an increase in incomes of $117,500 per year and improving quality of life in the region. The project would create a new business, run by a third-party company that would receive profits. With an estimate 23-year payback period, the current process is not yet economically feasible, but the economic outlook is expected to improve significantly after optimization, scheduled to take place in Phase II of the design process.
Planet: The algal biodiesel production will reduce the DANC facility’s dependence on fossil fuels by 27%, thereby reducing greenhouse gas emissions by 12% and sulfur oxide emissions by 31%. The biodiesel creates a renewable fuel source for the facility and develops technology for the beneficial use of waste products produced at landfill facilities.
Conclusions:
The addition of an algal biodiesel production to the DANC solid waste management facility will yield positive impacts across the P3 spectrum of people, prosperity and planet. The facility will provide local economic stimulus through job creation, improve regional air quality by reducing emissions, reduce truck traffic at the DANC facility and provide an opportunity for educational outreach on sustainability. This project promotes full-cycle sustainable practices in the form of a cradle-to-cradle process in local economy and successfully addresses the challenges of pursuing industrial sustainability in cold climates where resources such as potable water are limited. The sustainable design methods used in this project can be adopted by similar solid waste management facilities.
Journal Articles:
No journal articles submitted with this report: View all 4 publications for this projectSupplemental Keywords:
Algae, biodiesel, educational outreach, job creation, landfill leachate, waste heat recovery, sustainable practicesThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.