Removal of Microplastics from Biosolids and Understanding their Impacts on Agricultural Crops
Prior to their final deposition in aquatic systems, microplastics enter into municipal wastewater and are transferred to agricultural fields in the form of biosolids. Researchers and stakeholders are coming together to investigate ways to prevent microplastics from entering the environment and studying the effects of the remaining microplastics on agricultural soil fertility.
Identification of Methods to Remove Microplastics from Biosolids
Researchers are working with wastewater treatment plant operators to develop zero-cost solutions to keep microplastics out of the environment
Researching if Crops are Affected by Microplastics from Biosolids
Do microplastics from biosolids affect crops? Researchers are learning about the types and concentrations of microplastics and how they affect crops to help determine if additional processing steps are needed.
This Collaboration Has Two Research Avenues
Preventing Microplastics from Re-entering the Environment
Through targeting the removal and recycling of microplastics from biosolids, prior to their application onto land, we will prevent microplastics from re-entering the environment and help create a more environmentally sustainable biosolid product. We believe our short-term storage solution can substantially reduce microplastics in biosolids, but as each wastewater treatment plant is unique we want to hear your thoughts about the feasibility of integrating our range of solutions into your treatment plant.
Impacts of Microplastics on the Soil Fertility and Crops
In fertile fields, plants interact with the soil microbial community to enhance nutrient capture and promote healthy crop growth. However microplastics may be drawn to the root surface and interfere with this important partnership. This research investigates how many microplastics crops can tolerate and whether microplastics taken up into the edible parts of crops. Keep up to date on the latest research findings.
Calling Wastewater Treatment Plant Operators, Farmers, and Concerned Citizens to Action
Wastewater Treatment Industry: Help Prevent Microplastics from Entering the Environment
Join the Zero Plastic Waste Initiative forum to anonymously converse with other wastewater treatment plant operators, scientists and stakeholders and let us know if you think our solutions can help your treatment plant.
Learn About How Microplastics May Affect your Food
Join the Increasing Knowledge of Plastic Pollution Initiative forum to learn about the latest research.
The Microplastic Lifecycle
When passing through wastewater treatment plants, up to 99% of microplastics are transferred into biosolids, which are often applied to agricultural land as fertilizer. Studies have shown that large quantities of these land-applied microplastics are washed off the soils into watercourses, where their long-term impacts are unknown.
By working with wastewater treatment managers, this project will investigate methods of removing microplastics from biosolids, thus removing this source of microplastics from the environment.
Preliminary research has shown that short term storage of biosolids can passively and cheaply ‘float’ microplastics to the surface, which can then be easily removed. We will investigate whether these methods can be refined to support substantial reduction in biosolids MP content, and sufficient recovery of microplastics to support a new pathway of plastics recycling.
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A comparison of biosolids microplastics content between stored and unstored biosolids (adapted from Crossman et al., 2020)
Studies have indicated that storing biosolids can help to reduce microplastics content before they are applied to land.
Microplastics applied to land through biosolids risk being rapidly transferred to local watercourses through runoff. Surface flow generated from agricultural fields receiving biosoids have been shown to contain nearly double the plastic content of those where it was not.
Providing evidence-based science over environmental concerns
Due to their small size, microplastics from biosolids may be drawn through the soil against the surface of roots. The boundary between the root and the soil controls how nutrients are taken up into the food web, whether plants can form beneficial associations with root-symbionts. It also controls whether microplastics can enter into the root system and if they can be transported to the edible parts of plants.
By monitoring the growth and development of the root system in microplastic contaminated soil using specialized containers with a transparent side, researchers can identify specific roots that are experiencing stress. Stressed roots will be targeted with additional analysis for evidence of microplastic induced stress in the normal functioning of the root and soil microbial community. The microplastic concentrations in the soil and roots will be further assessed to determine the types and concentrations of microplastics that are uptaken into important agricultural crops.
Few studies have examined plant roots exposed to biosolid derived microplastics, and the impacts on soil fertility and crops remain largely unknown. We will investigate multiple lines of evidence to determine whether microplastics are a stressor on crops to inform efforts to develop viable biosolid treatment options.
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Microplastics in agricultural soils, with and without application of biosolids (Crossman et al, 2021 – unpublished data)
Microplastics contents in agricultural soils where biosolids have been applied has been found to be over fifteen times higher than that where it is not. This program will investigate the impact of these higher concentrations of microplastics on crop viability