Enguera, the town of Valencia where the countryside is fed with leftover food from the houses | Spain

Miguel Juan tells, Councilor for Health, Citizen Participation, Animal Welfare and Sports of Enguera (Valencia, 4,911 inhabitants), that an 80-year-old resident of the town “every Friday, at noon, waits for the volunteers who collect the biowaste that accumulates in a paint can that she has in the garage.” Vegetable peelings, fruit skins, even leftover macaroni, meat, bones or fish scraps. Like her, 70 families in the Valencian municipality separate what they leave on their plates and put it in municipal containers, which are emptied every week in a Bodegas Enguera composter. There, they are mixed with animal manure, waste from oil production and pruning remains to create a compost that is applied to 12 hectares of vineyards, under the supervision of the Agrocompost project techniciansof the Miguel Hernández University of Elche (UMH)the first in Spain to have obtained an exception in current regulations to be able to test the use of food scraps in the production of organic fertilizers for agricultural use.

Pending the entry into force in Spain of the law 7/2022 on waste and contaminated soils for a circular economywhich is scheduled for April next year, domestic and agricultural waste will be legislated separately. In the Valencian Community, “Law 5/2022 of the Generalitat regulates that agricultural and livestock waste can be composted without economic exchange,” says Ana García Rández, professor at the Agrochemistry and Environment unit at the UMH. On the other hand, “order 18/2018 of the Department of Agriculture regulates community composting that can use household waste remains on a small scale.” The academic entity from Elche fights so that the farmer can take care of this domestic waste because they believe “that the synergy between agriculture and the urban environment is important.” Agrocompost, on an experimental basis, united the two flows, “through an agreement established with the Ministry of Agriculture and the UMH that has already been in place for six years throughout the Valencian Community.” In total, it is developed in 215 different projects, with which 15,537 tons of waste have been composted.

In the area of ​​using food scraps to fertilize fields, Enguera’s project is the most significant. The winery had already made progress in the use of compost, “a high-quality organic fertilizer,” according to Juan Martínez Barberá, head of R&D&i for the wine company. In 135 hectares of vineyards and 45 hectares of olive groves, they use “manure from rabbit farms or bats bred for this purpose.” They add “the alperujo, which is the residue from the production of olive oil, and pruning remains.” Since 2018, they entered Agrocompost together with the City Council, “which showed its interest in composting organic waste” that they apply to the 12 hectares of vineyards that surround the winery. In Enguera, Martínez recalls, “there were already community compost bins on several streets in the town, but the lot where they met was sold” and they were left unused. So when, “in a few days, the winery indicated that it wanted to join the UMH project,” they immediately accepted. “For us it was perfect,” continues the mayor. “It had two advantages. An environmental one, because we reduce the carbon footprint and put the value of the waste to benefit the ecosystem. The other, economic, because by reducing the collection rate, the garbage truck passes less frequently and does not take waste to the plant.” “Our intention is that the organic does not leave the town,” he says.

The process is carried out using four 80-liter community municipal containers into which about 70 families dump biowaste, plus five houses in which collection is done door-to-door, because they belong to older people. They gather about 300 kilos per week. In Enguera and other similar projects, such as that of Atzeneta del Maestrat (Castellón, 1,319 inhabitants), the UMH “analyzes the compost to establish its physicochemical properties and at a microbiological level, to detect the possible presence of pathogenic microorganisms such as salmonella or e- coli,” says García Rández. It is also ensured that it reaches “at least 55 degrees of temperature, to sanitize it and eliminate pathogens,” and that it obtains sufficient oxygen, through periodic turning. “Compost from domestic biowaste provides large amounts of nitrogen, phosphorus and potassium, the most important micronutrients for the countryside,” he says. “It is much richer than the exclusive use of prunings, it is high in organic matter and correct in electrical conductivity, which measures salinity.”

For the countryside, the remains of human food, combined with a synthetic mineralization appropriate to the needs of each soil, are the equivalent of a nutritious and healthy Mediterranean diet. It provides “nutrients and water, avoids desalination, in experiments carried out in real fields, it has been seen that it generates less CO2 emissions, that it produces the same amount of grain and that the fruits have more polyphenols and better palatability,” adds Raúl Moral. , professor of Soil Science and Organic Chemistry and director of the University Institute of Agri-Food and Agro-Environmental Research and Innovation of the UMH. They are a “virtuous” alternative to inorganic fertilizers that are “very efficient, if managed well,” but that “generally have been applied more than necessary, perhaps because it was thought that they would give more production.” “This has led, for example, to the contamination of aquifers, as has happened in the Mar Menor of Murcia,” he maintains.

Moral also highlights the economic factor of using organic fertilizers. Not only because it would reduce municipal waste management rates, by reducing the amount of material that is transferred to processing plants and landfills, but because it would alleviate the effect of the war in Ukraine, which skyrocketed the prices of synthetic fertilizers and activated the search for suitable regulations by the European Union (EU). The professor recognizes that “to achieve the same effect as inorganic waste, biowaste requires a much larger quantity: 100 or 200 kilos per hectare of synthetic waste is equivalent to 20,000 kilos of compost.” The solution consists of “mixing both materials, using hybrid fertilizers that provide the compost with the nutrients it lacks. Thus, its use would be 500-600 kilos per hectare.” For now, its effectiveness has been demonstrated in small municipalities. “Now it needs to catch on in the big cities as well,” concludes Moral.