巴西污水污泥变身生物肥料，中资农业投入品采购或迎替代窗口

Waste being turned at Tera Ambiental; fertilizer made from sludge reduces fertilizer costs Divulgação When a sewage treatment plant finishes its work, it leaves behind not only clean water but also another byproduct: sludge. For decades, nearly all sewage sludge was sent to landfills. In recent years, however, geopolitical turmoil that disrupted fertilizer imports has helped turn the material into an input for producing biofertilizers because of its high concentration of organic matter and nutrients. The alternative is already attracting investment and generating revenue. Agriculture Ministry data show that Brazil registered 33 biofertilizers developed by 17 companies between 2019 and June 2026. However, no information is available on how many are made from sludge. Institutions such as the Brazilian Agricultural Research Corporation (Embrapa) and the Food and Agriculture Organization of the United Nations (FAO) have documented the agronomic benefits of biofertilizers. Advantages include increasing the availability of essential soil nutrients, improving microbiological activity, partially reducing the need for synthetic fertilizers, and lowering environmental impacts. According to experts, biofertilizers can supplement or even partially replace chemical fertilizers, increasing the efficiency of production systems. Cristiano Andrade, a researcher at Embrapa Environment, explained that organic products can replace up to 100% of mineral nitrogen fertilizer. He cautioned, however, that not all sewage sludge is a good source of potassium. “In the case of phosphorus, applying sludge does not immediately replace mineral fertilizer. But successive applications of sludge in the same area produce a gradual increase in the phosphorus available to plants, as shown by soil analyses, generating medium- to long-term savings on phosphate fertilizer,” he said. Tera Ambiental, which recycles industrial and municipal effluent, is among the companies already producing sludge-based biofertilizer. Company director Lívia Baldo said studies show Tera’s fertilizer can reduce mineral fertilizer use by 30% when approximately 5 tonnes are applied per hectare—one hectare is 10,000 m², or about two and a half acres. With continued use, soil fertility increases and the reduction approaches 50%, primarily lowering the need for nitrogen (N) and phosphorus (P). The company partners with Orizon, which operates the Paulínia landfill in São Paulo state, and an ecopark in the municipality where it produces 1,600 tonnes of organic fertilizer a month. Tera also manages effluent sent to the Jundiaí Sanitation Company (CSJ) and receives sludge from other sewage treatment plants in the region, as well as effluent from industries and other companies. Tera Nutrição Vegetal, the company’s division serving the sector, sells organic fertilizer for agriculture and landscaping. Customers already use it on crops including sugarcane, coffee, citrus, fruit, and vegetables. The company has also tested it on tomatoes, bananas, macadamia nuts, soybeans, and corn, achieving productivity gains and improved quality, Baldo said. “The company uses raw materials that meet the technical and environmental criteria established by law, focusing on organic sludge—primarily from sewage treatment plants—and other licensed organic waste,” she added. Some companies are betting on the potential of agribusiness supply chains, which both generate waste and require fertilizer. Agribusiness is one area targeted by Santa Catarina-based Quattro T, which specializes in industrial waste management. The company dredged an 11,500-meter settling pond for an agribusiness company in Paraná and simultaneously reduced sludge generation by 61% within a few days, said Quattro T Chief Operating Officer Eduardo Rotta Lovato. The sludge never left the property. The company served by Quattro T began using biosolids made from the sludge to fertilize farmland near its settling pond, replacing fertilizer it had previously purchased. “What had been a cost to transport and dispose of the sludge in a landfill became a source of savings,” Lovato said. Quattro T used hydraulic dredging combined with geotextile bags, which separate water from solids. In this case, the process recovered 8,886 cubic meters of water and avoided emissions of 1,352 tonnes of carbon dioxide equivalent. French water and waste management company Veolia has also recognized the potential of recycling sludge. The company launched a small-scale project in Blumenau, Santa Catarina. “We want to have these solutions ready in Brazil to meet the demand that will emerge here,” said Gustavo Lara, executive manager of water and sanitation business development at Veolia Brazil. Through its stake in water and sanitation concessionaire Águas Andinas, the company already operates a biofactory in Santiago, Chile, that converts sewage sludge into biofertilizers. The business grew to the point that it had to create a separate company to bag, market, and distribute the product to the local agricultural market. “We produce tonnes of biofertilizer in the country,” Lara said. He believes the project could serve as a model for Brazilian business, depending on regulatory pressure and landfill disposal costs. The issue is also drawing the attention of sanitation companies. At Iguá, one of Brazil’s largest companies in the sector, the Move Iguá Inova program brought together employees from different departments to propose solutions to real operational problems. It selected 13 initiatives, three of which address sludge treatment. The proposed solutions involve accelerated drying, heat treatment, and reducing sludge volumes at treatment plants. Paula Violante Divulgação The goal is to reuse waste “in ways that make sense for each operational and regulatory setting,” said Paula Violante, chief operating officer (COO) of Iguá Saneamento. “Innovation in sanitation is not limited to digitization or automation. It also includes how we address complex operational challenges such as sludge management,” she said. Interest in biofertilizers grows, but high costs remain a hurdle Although interest in producing sludge-based biofertilizers is growing in Brazil, the alternative still faces significant obstacles to gaining traction. The industry cites low production volumes, high final-product costs, and continued weak demand as the main barriers. According to Lívia Baldo, a waste-management specialist and director at Tera Ambiental, one challenge is the yield because the biofertilizer is produced from a large volume of organic waste. To produce Tera Base, its organic fertilizer, the company processes one tonne of organic waste and generates about 400 kilograms of finished product. It produces 36,000 tonnes a year of screened, Class B composted organic fertilizer containing 70% solids. The cost of sludge-based products for farmers is another challenge. Eduardo Rotta Lovato, chief operating officer of industrial waste manager Quattro T, acknowledged that biofertilizer cannot compete with conventional fertilizers on price. Demand currently comes from consumers already concerned with improving soil quality and reducing their environmental impact. “Every production process requires scale, and in the case of biofertilizer, it is unlikely that we will achieve industrial scale at a single production facility,” Lovato said. Logistics is another bottleneck. Operations remain regional, and Brazil’s transportation system makes long-distance distribution more expensive. Regulatory clarity is also lacking. The Agriculture Ministry has no specific classification for sludge-based biofertilizers, which are currently classified generically as organic fertilizers. Producing fertilizer from sludge is neither simple nor fast. The process involves stabilization and sanitation steps, including heat treatment, thermophilic composting, or stabilization with calcium oxide, which eliminate pathogens and make the material safe for agricultural use. After undergoing one of these processes, the material is classified as a biosolid and then formulated as an organic fertilizer, organomineral fertilizer, or biofertilizer. A 2020 resolution issued by the National Environmental Council (Conama) establishes criteria and procedures for producing biosolids and classifying them according to the bacterial load of Escherichia coli. The regulation also establishes classification criteria based on potentially toxic chemical elements that may be present in the sludge. Despite the challenges, some state capitals already have sizable operations. In Rio de Janeiro, all sludge generated at wastewater treatment plants (ETEs) is sent to Organosolo, which uses thermophilic composting to convert the material into organic compost for agriculture, gardening, and reforestation. Cuiabá has also had a similar operation since 2022. Translation: Todd Harkin