11 February 2021

Confirmation from the US that composting helps soil and the climate

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Composting is extremely useful, resulting in less waste sent to landfill, lower emissions and healthier soil, but it needs careful management. The experience in Ohio

by Matteo Cavallito

Composting? An effective solution to reduce the environmental impact of landfill sites and promote healthier soil. This has been confirmed by a study by Case Western Reserve University of Cleveland, in the United States, which for some time has undertaken a sustainable waste management project. The initiative, which is based in the university’s canteens, is linked to the individual waste collection programme, making a contribution to counter a worrying phenomenon. The university notes that every year the United States generates 300 million tonnes of landfill waste (almost one tonne per capita), with the state of Ohio the unfortunate national leader generating “approximately 14 pounds per person per day”. Which is equivalent to over 2,300 kg per person per year.

Composting reduces CO2 emissions and improves soil health

The use of organic waste in the soil is known to be a practice with great potential. In the case of composting in particular, the interaction of the different elements produces a virtual circle from many perspectives. The operation – which consists in producing an organic mixture which is created by the action of microorganisms on a mass of biodegradable waste – takes place in the presence of oxygen. In other words, it does not produce methane. What’s more, the decomposition produces lower CO2 emissions and generates heat, creating ideal conditions for fungi and bacteria and creating a self-sustaining process. The finished product can be used as fertiliser and the addition of food waste, grass and leaves adds to its nutrient content. According to the study, when applied to the soil mixed with manure it can help improve water retention while also limiting soil erosion.

Ohio following California’s lead

In Cleveland, a company called Rust Belt Riders, or RBR (a reference to the nickname for the north-east United States, once the country’s industrial heartland), promotes the production of compost by local citizens. The service is based on similar initiatives in California and Vermont for the collection of compost and recycling. RBR, which generates different soil blends, has signed an agreement with the university to transport the compost generated from canteen waste thanks to its collaboration with another company: Bon Appétit Management Company. According to the university, in around a year of activities the initiative, which was launched in 2019, produced 125 tonnes of compost. In environmental terms, this saved 9.5 tonnes of CO2 from entering the cold air of Ohio.

Compost, a global resource (to be managed with care)

However, while the university acknowledges this promising result, the collection of bio-waste is hindered by an unexpected factor: contamination. On more than one occasion, the students responsible for initial collection of waste ended up inadvertently mixing the waste with other unsuitable materials like plastic and metals. This led the university to suspend the project until a solution could be found, highlighting the vulnerability of the compost production process. An unresolved problem that requires careful attention, but one that in no way detracts from the potential of this valuable resource.

The Food and Agriculture Organisation (FAO) is well aware of this potential, and in 2015 it drafted a veritable manual for farmers which collates the results of a series of experiments on production of compost in Latin America. The goal is to set out the techniques necessary to produce a product that can be used as a natural fertiliser, helping to reduce waste production and cut farmers’ costs.