Page - 286 - in Freshwater Microplastics - Emerging Environmental Contaminants?

Another analysis of GHG emissions compared the current strategy in Los Angelesof landfillingthevastmajorityofwaste toacombinationof threestrategies in a modern MRF, namely, (a) anaerobic digestion of wet waste, (b) thermal gasification of drywaste, and (c) landfilling residuals [87]. Their analysis did not consider economic, environmental, or socialparameters, onlyGHGemissions, and wasbasedonanassumptionof1,000tonofwasteperdayenteringeachscenariofor 25 years; then theymodeled theGHGemissions for the century that followed. In each scenario, the GHG emissions from transportation, operation, and avoided emissionsby replacing fossil fuelswere factored in.Results showed that continued landfilling resulted in a net increase of approximately 1.64millionmetric tons of carbon dioxide equivalent (MTCO2E), while the MRF scenario results in a net avoidedGHGemissionsof (0.67)millionMTCO2E,showing that ashift toaMRF wheremultiplewastemanagement strategies areemployed resulted ina totalGHG reductionof approximately 2.31millionMTCO2E. Those residuals that exist after diversion of waste to recycling and anaerobic digestioncouldbe landfilled, and in somecaseswaste-to-energycouldhavea role. This would be appropriate only after diversion efforts of recyclables and compostables have been maximized. Also, building incinerator infrastructure could create tremendous debt or include a demand for large volumes of waste, alsocalleda“wastequota” thatcouldundermine localefforts toeliminateproducts and packaging that generatemicroplastics. Simultaneously, amarket for recycled materialsmustbeencouraged,whileall environmental andworkerhealthconcerns areprioritized.Waste-to-energycouldhavea role,but longafter allotherefforts to managewaste havebeen employed. Section Summary In the linear economy contrasted with the circular economy, we see twoworld views on how to solve the plastic pollution problem.While the linear economic system benefits production by eliminating competition from recycledmaterial, it ismorepolluting than the circular systembecauseofmultiple points of leakage along the supply chain. Plastic pollution is lost at production as pellet spills, lost by the consumer as litter with no inherent value, and lost at collection and disposal as waste is transported. In the circular system these are mitigatedwhensystems to focusonmaterial control andcapture are implemented. Zero waste is the ideal of the circular economy, where the need for destruction through energy capture, or landfill, are increasingly unnecessary. 6 MicroplasticMitigationThroughaCircularEconomy In the emerging circular economy, the flowof technicalmaterials through society returns to remanufacture, with products and packaging designed for material recovery, lowtoxicity,easeofdismantling, repairandreuse,andwhere thisdoesn’t work, a biological material may substitute so circularity in a natural system can prevail. Shifting to a circular economy has prompted interest in a range of 286 M.Eriksen et al.