The core of the circular economy is “closed-loop resource flow and maximized value utilization,” and sludge, as the end product of wastewater treatment, has always been a challenging issue in the environmental protection field. Can converting sludge into fertilizer become a priority for the circular economy? The answer requires a comprehensive assessment—provided that harmless treatment is ensured, this conversion path undoubtedly possesses the core logic to become a priority.
From a resource recovery perspective, sludge contains abundant organic matter, nitrogen, phosphorus, and other nutrients, which are core raw materials for organic fertilizer production lines. Converting sludge into fertilizer achieves a precise closed loop of “waste-to-resource,” avoiding nutrient loss and resource waste caused by sludge landfilling and incineration, perfectly aligning with the core goal of the circular economy: “turning waste into treasure.”
From an environmental burden reduction perspective, traditional sludge disposal methods (landfilling, incineration) easily cause leachate pollution of soil and water bodies and the emission of harmful gases. Converting sludge into fertilizer can significantly reduce the environmental pressure of sludge disposal, while also reducing the reliance on mineral resources for fertilizer production, forming a green chain of “wastewater treatment – sludge resource utilization – agricultural application,” providing a crucial path for the ecological benefits of the circular economy.
It must be emphasized that the prerequisite for “priority” is harmless treatment. It is essential to build a strong defense line through technologies such as high-temperature composting and heavy metal removal. The high-temperature composting process often requires key organic fertilizer production equipment such as compost turning machines to ensure even heating and thorough composting of the sludge, ultimately ensuring that the sludge fertilizer meets safety standards and avoids secondary pollution.