Super Hero... Organic Waste?

By Petronilo Morin IV

Measuring circularity of resources can provide insight of the performance of a circular economy, and previous methods have proved to be flawed. However, a methodology proposed by Cobo et al., (2018) allows the tracking, processing, and recovery of organic waste within a Circular Integrated Waste Management System (CIWMS). Below shows the flows of the components of a given waste stream within the CIWMS.

The study, which was recently conducted in Spain, followed the flow of organic waste in a management system maximized the circularity indicators of carbon, nitrogen, and phosphorus. It focuses on the tracking of three essential soil nutrients, phosphorus, carbon, and nitrogen because an imbalance of either of these elements could have consequences on crop production.

The flow of organic waste in the CIWMS was calculated mainly using the equation shown below.

Where i, is the component of a given waste and CI_i is the amount of component i, that extends its lifespan that provides a service to another process with respect to the quantity of component i, present in the accumulated waste. The further explanation of the variables using linear algebra can be found in the aforementioned literature. Results from utilizing these equations yielded life cycle assessments that were tested against model environments obtained from the Environmental Assessment System for Environmental TECHnologies (EASETECH).

In summation, it was observed that improving nutrient circularity lead to eutrophication in environments and that increasing separation rate of the organic waste resulted in a more positive carbon footprint on the system. However, trade-offs between these indicators have not yet been seen literature due to the lack of sufficient research.

Reference

Cobo S., Domniguez-Ramos A., and Irabien A. 2018. Trade-Offs between Nutrient Circularity and Environmental Impacts in the Management of Organic Waste. Environ. Sci. Technol. 10.102