Microplastic remediation


Microplastic remediation refers to environmental remediation techniques focused on the removal, treatment and containment of microplastics from environmental media such as soil, water, or sediment.
Microplastics can be removed using physical, chemical, or biological techniques. Though efforts are underway in directly removing microplastics from the environment, the biggest factor in microplastic remediation remains prevention. Implementation of policy and protocol for the collection and re-use of plastic products prevents the majority of opportunities for microplastics to form in the environment.
Microplastic remediation is global effort which aligns with the United Nations Sustainable Development Goals. Direct impacts to the environment, as it pertains to the SDGs, include SDG 6 concerning clean water and sanitation, SDG 12 as the production and use of plastic materials directly contribute the creation of microplastics, and SDG 14 where microplastics have invaded the waters and sediments, affecting aquatic life.

Remediation of microplastics in air

Microplastics can be airborne and have been identified in both air and dust samples from both indoor and outdoor locations in China and London, among others, with indoor microplastic levels being higher than outdoor levels. More studies are needed to measure the impact of microplastics as part of airborne particulate matter on human health.
Removal of airborne microplastics is challenging and the best strategy is to improve indoor ventilation and to reduce emission by reducing use of synthetic textiles and by using HEPA filters when vacuuming. HEPA air filters can reduce indoor airborne particulate matter and might be similarly effective for microplastics removal.
Incineration of plastics for energy is a large contributing factor to airborne microplastics. It has been observed that switching from plastic burning to renewable technologies for the production of energy is a viable method of microplastic remediation for airborne microplastics by eliminating a major source.

Remediation of microplastics in water

Microplastics can be removed from water by filtration, adsorption or absorption.
Absorption devices include sponges made of cotton and squid bones, demonstrating an efficiency of over 99%.
Researchers have shown that microplastic remediation in water can also be accomplished by utilizing plant-based polymers from Fenugreek and Okra as flocculants. The flocculation process utilizes the unique structure of the polymers created from the sugars of Fenugreek and Okra as adsorption vectors. Once the microplastics have been captured by the polymers in the flocculation process, the polymers settle to the bottom of the solution and are filtered out. Utilization of these polymers for flocculation results in an average of 80% of microplastic removal from water.
Polyacrylamide has also been found to be an effective flocculant for removing microplastics from water.
Biofilters, such as biochar filtration, have been used in wastewater treatment plants. The biochar acts as an adsorbent and is capable of removing up to 97% of microplastics from effluent.
Efforts to physically remove microplastics from the Great Pacific Garbage Patch have used nets and collection bags. The method of netting or bagging plastics in the ocean involves pairs of ships pulling large bags or nets, like plankton nets, to remove the plastics.

Remediation of microplastics in soil and sediments

Microplastics are commonly found in soil and sediments. Techniques are under development to achieve reductions in soil microplastics via photodegradation, chemical extraction, or bioremediation. Additionally, density separation has been found to be an effective technique for microplastic remediation of sediments.
Density separation involves saturating a volume of water with salts, such as NaCl or ZnCl, and dissolving the sediments. The microplastics are less dense than the saturated water which causes them to float to the top and can be removed by decantation.
Biodegradation of microplastics has been accomplished in soils and sediments by utilizing microorganisms, such as bacteria or fungi, that are capable of eating the plastics as a food source. The soils and sediments are placed in a bioreactor with the chosen microorganism which allows for the breakdown of the plastics.