Urban Food Lab: Composting Plastic in Aquaponics

EPA Grant Number: SU840144
Title: Urban Food Lab: Composting Plastic in Aquaponics
Investigators: Silverman, Andrea , Gowayed, Omar , Acklin, Josh , Moosa, Tahany , Moratos, Angelica , Sookchan, Savannah , White, Gianna , Charytan, Natan , Ryu, Chaehyun , Gupta, Yams
Institution: New York University , Mount Sinai School of Medicine
EPA Project Officer: Spatz, Kyle
Phase: I
Project Period: December 1, 2020 through November 30, 2021 (Extended to November 30, 2022)
Project Amount: $24,972
RFA: P3 Awards: A National Student Design Competition Focusing on People, Prosperity and the Planet (2020) RFA Text |  Recipients Lists
Research Category: P3 Awards , P3 Challenge Area - Sustainable and Healthy Communities

Description:

Recent research has shown the ability of fungi, bacteria, and worms to degrade polyurethane (PU), polyethylene terephthalate (PET) and polystyrene (PS) foam, respectively, using controlled composting systems. These systems have been found to effectively biodegrade plastics into carbon rich materials that can be used as a nutrient source for plants. Unfortunately, toxic materials such as microplastics in the PU and PS foam compost products, and ethylene glycol and microplastics in the PET compost product, pose a barrier to scalability and use of these novel plastic composting techniques. The challenge is further complicated by the existence of contaminants like binding agents and dyes in commercial plastics, and variable material shapes and densities. The goal of this project is to assess the presence of microplastics and other toxic byproducts in plastic compost products, evaluate their removal through novel compost methods and filtration, and test the feasibility of using these biological composting techniques to reduce plastic waste and provide a nutrient source within a vertical aquaponic farming system.

Objective:

This project will be conducted according to three objectives: (1) build fungi-, bacteria-, and worm-based composting systems to compost polyurethane, polyethylene terephthalate, and polystyrene foam mixed with food waste, and monitor the relative decomposition of plastics within the these systems; (2) conduct a systematic evaluation to determine the toxicity of the resulting compost products, through germination tests and an evaluation of kale growth within an aquaponic farm system; and (3) evaluate aqueous compost solutions and plant matter grown from these solutions for the presence of microplastics, using spectroscopic methods [e.g., Fourier-transform infrared spectroscopy
(FTIR)].

Approach:

Three separate composting systems will be built to evaluate composting a mixture of plastics and food waste: (i) polystyrene (PS) will be composted using mealworms, (ii) polyurethane (PU) will be composted using a fungus called Aspergillus tubingensis, and polyethylene terephthalate (PET) will be composted using a bacteria containing a gene that allows degradation of PET. Each system will be evaluated to assess the rate of plastic degradation over time.


To assess the amount of microplastic byproducts in the solution, as well as examine the relative toxicity of the degraded commercial plastics in the compost, samples from each system will be observed using spectroscopic techniques and toxicology screenings. Solid samples will be turned into a compost tea by placing them in a mesh filter bag with a 1 μm pore size and placed in aquaponic water. Liquid compost product samples will be mechanically filtered through a mesh filter with a 1 μm pore size, then added to an aqueous solution of aquaponic water (i.e., aquarium water that serves as a nitrogenous nutrient source for plants) to assess toxicity; filtration will be used to reduce the concentration of the microplastics. Toxicity will be examined in the following ways: (i) common practice germination tests, (ii) daily health monitoring of kale plants grown in aquaponic water with compost products added, and (iii) spectroscopic techniques, such as Dynamic Light Scattering and FTIR, to determine the size and existence of plastic nanoparticles within the filtered solutions and plant matter.

Expected Results:

Findings from this project will deepen our knowledge of how composted food and plastic waste can be used as a supplementary nutrient source for plants in aquaponic and hydroponic systems. We anticipate that the proposed experiments will produce data that will aid in the design of novel, scalable systems for plastic degradation on farms, including the development of guidelines for on-farm plastic composting using mealworms, fungi, and bacteria, the assessment of lifecycle costs of plastic composting, and development of cost-saving measures for vertical farming systems. Finally, it will inform farmers of potential risks, costs, and mitigation techniques for composting plastics within a vertical farming setting. Given the benefits of providing resources for vertical farms, assessing potential cost savings for farms, and developing waste reduction strategies, this project has outcomes to support people, prosperity and planet.

Publications and Presentations:

Publications have been submitted on this project: View all 1 publications for this project

Supplemental Keywords:

Microplastics, compost, toxicity, sustainable development, clean technologies, waste reduction, waste minimization, bioremediation, community-based, aquaponic agriculture

Progress and Final Reports:

  • 2021 Progress Report