Development of an Algal-based Landfill Leachate Treatment System

Dr. Thinesh’s project is focused on the potential of using thermophilic mixotrophic algae, Galdieria sulphuraria to efficiently perform on-site treatment of leachate.

PROJECT PI

Dr. Thinesh Selvaratnam, Assistant Professor, Department of Civil & Environmental Engineering

SHORT DESCRIPTION

The proposed research will develop an algal-based on-site bioremediation pathway to treat leachate. In addition to the nutrient removal, algal biomass produced from this system can be used for biofuel production, value-added bioproducts, and livestock feed supplements. Successful implementation of the proposed system will reduce the current leachate treatment costs and will provide an avenue for supplemental revenue from the produced algal biomass.


FULL DESCRIPTION

The Resource Conservation and Recovery Act of 1986 mandates all landfills to collect leachate, and Effluent Guideline and Standards (2000) require leachate from non-hazardous landfills to be treated before releasing to the environment. Landfill leachate is high strength wastewater containing a variety of inorganic species and organic wastes that can possess chronic and acute toxicity. There are 3,000 active landfills and 10,000 or more inactive or closed landfills across the United States. Depending on the landfill size and age, costs associated with the treatment of leachate range between hundreds of thousands to millions of dollars per year. The most common method for handling and treating leachate is to collect and transport to a Publicly-Owned Treatment Works (POTWs) where it is co-treated with municipal wastewater. However, it has recently been observed that a significant number of landfill operators encounter treatment issues with off-site disposal of leachates at POTWs. These issues stem from leachate quality parameters to the available capacity of POTWs. For example, POTWs are increasing the treatment costs of leachates based on some water quality parameters exceeding certain limits. The POTWs are more concerned about the effects of these components on the performance of the proceeding biological treatment processes, and thus in some cases, the POTWs are reluctant to accept any leachate for treatment. Current treatment technologies are mainly focused on the reduction/removal of classical water quality parameters such as nutrients and COD. However, there is a growing need for advanced treatment technologies focused on the removal of Contaminants of Emerging Concern including Pharmaceuticals and Personal Care Products (e.g., perfluorinated chemicals (PFCs)). Therefore, it is vital to develop sustainable, cost-effective on-site leachate treatment technologies focusing on near and longer-term contaminant issues. Long-Term plans need to be made to minimize the total investment in leachate treatment.

The proposed research will develop an algal-based on-site bioremediation pathway to treat leachate. In addition to the nutrient removal, algal biomass produced from this system can be used for biofuel production, value-added bioproducts, and livestock feed supplements. Successful implementation of the proposed system will reduce the current leachate treatment costs and will provide an avenue for supplemental revenue from the produced algal biomass.

Earlier efforts in developing algal-based systems to treat leachate often require multifold dilution of leachate to enable biological growth, which severely impacts the sustainability of the processes implemented to date. This proposed research will evaluate the potential of using thermophilic mixotrophic algae, Galdieria sulphuraria to efficiently perform on-site treatment of leachate. The PI has developed an algal-based system to treat municipal wastewaters and lead the effort of pilot scale implementation of the system in the municipal wastewater treatment plant, Las Cruces, New Mexico.

Dr. Thinesh will lead the project research to perform the following tasks:

· Evaluation of nutrient, COD/BOD removal and algal biomass growth using landfill leachate (Lab scale and Pilot-scale reactors, 1L to 25L). Specific importance will be given to reduce the hydraulic retention time of the proposed system

· Evaluate the mixotrophic pathway to optimize the process performance using a waste carbon source (e.g., anaerobic digester centrate from municipal wastewater treatment plants).

· Field deployment of algal reactors for leachate treatment and process optimization.

· Evaluation of the economic advantage of algal-based treatment compared to current technologies.

· Assessment of potential pathways to utilize the produced algal biomass.


Research Group

Shanglei Pan (Doctoral Candidate)

Burgandy Petri (Graduate Student, 2018-2019)

Kyleigh Dixon (Undergraduate Student, 2018-2019)


FUNDING

Center for Advances in Water and Air Quality, Lamar University


Publications

Nawas, T., Pan, S., Burgandy, P., Dixon, K., Selvaratnam, T. (2019). “A Review of Landfill Leachate Treatment by Microalgae: Current Status and Future Directions”, Algal Research. Under review.

Nawas, T., Selvaratnam, T. (2019). “Resource Recovery from Reverse Osmosis Concentrate as a Solution to Water Crisis: A Technological Assessment”, Book Chapter, under revision (accepted for publication).