In daily life, improper handling of animal carcasses such as sick or dead livestock/poultry and pet remains can easily breed bacteria, spread diseases, and may even contaminate soil and water sources, threatening public health and the ecological environment. Therefore, the harmless disposal of animals has become a crucial link in blocking the spread of diseases and safeguarding environmental security. So, what are the current mainstream methods for the harmless disposal of animals, and which scenarios are each suitable for?  

I. Incineration Method: High-Temperature Inactivation, Suitable for High-Risk Animal Carcasses  

The incineration method involves completely burning and carbonizing animal carcasses using high-temperature flames. It destroys the protein structure of pathogens at temperatures above 800°C to achieve complete inactivation. Its operation process usually involves: feeding the animal carcass (which needs to be cut first if it is large in size) into a professional incinerator, adding combustion aids to ensure full combustion, and filtering smoke and harmful gases (such as dioxins) through an exhaust gas treatment system to avoid secondary pollution.  

This method is suitable for animal carcasses carrying highly pathogenic diseases (e.g., African swine fever, avian influenza), animal remains that died from unknown causes, and batch livestock/poultry culled due to major epidemics. Its advantages are thorough inactivation and fast processing speed; its disadvantages are high energy consumption and the need for supporting strict environmental protection facilities to control exhaust gas emissions.  

II. Burial Method: Underground Isolation, Suitable for Small-Sized, Low-Risk Carcasses  

The burial method involves placing animal carcasses in standard deep burial pits, achieving harmlessness through the physical barrier of soil and the decomposition of microorganisms. Standard burial procedures require attention to the following: the site must be far from water sources, farmland, and residential areas (at least 100 meters away from drinking water sources), with a pit depth of no less than 2 meters; the bottom of the pit is paved with an anti-seepage membrane and quicklime; after placing the carcass, a layer of quicklime is covered, followed by filling and compacting the pit with soil; finally, clear signs and protective measures are set up to prevent digging by animals or leakage from rainwater.  

This method is suitable for handling small animal carcasses (e.g., pet cats and dogs), livestock/poultry carcasses with no disease risk, and is used when the processing volume is small. Its advantages are low cost and simple operation; its disadvantages are occupying land resources and a long decomposition cycle (usually 1–3 years). Improper site selection or operation may lead to the risk of pathogen infiltration contaminating soil and groundwater.  

III. Rendering Method: High-Temperature and High-Pressure Decomposition, Enabling Resource Reutilization  

The rendering method uses high-temperature (120–150°C), high-pressure (0.15–0.25 MPa) steam or chemical agents (e.g., organic acids, alkalis) to decompose organic substances such as proteins and fats in animal carcasses into harmless liquid or solid substances. During the processing, the carcass is first crushed, then put into a sealed rendering tank, and reacted in a high-temperature and high-pressure environment for 2–4 hours. The final products can be divided into oil (usable for producing biodiesel and industrial oil) and meat and bone meal (which can be used as raw material for organic fertilizers after further processing).  

The rendering method is suitable for batch processing of sick or dead livestock/poultry (e.g., pigs, beef cattle) and regular harmless disposal in breeding enterprises, especially for large-scale breeding scenarios. Its advantages are thorough harmlessness, realization of resource recycling, and no risk of secondary pollution; its disadvantage is high initial equipment investment, requiring professional personnel for operation and maintenance.  

IV. Fermentation Method: Microbial Degradation, Suitable for Small-to-Medium-Sized Animals and Livestock/Poultry Wastes  

The fermentation method uses the decomposition effect of microorganisms (e.g., bacilli, yeasts) to mix animal carcasses with auxiliary materials such as straw and sawdust. Under suitable temperature (55–65°C) and humidity conditions, aerobic fermentation decomposes organic substances in the carcasses into harmless organic fertilizers. The specific process is: crushing the carcass, mixing it with auxiliary materials in a certain proportion, stacking it or placing it in a fermentation tank, turning the pile regularly to ensure sufficient oxygen, and after 20–30 days of fermentation, the product can be used as fertilizer after passing quality testing.  

This method is suitable for handling small-to-medium-sized animal carcasses (e.g., poultry, rabbits) and wastes such as livestock/poultry internal organs. It is environmentally friendly and can realize "turning waste into treasure". However, it is necessary to control fermentation conditions; insufficient temperature or improper humidity may lead to incomplete degradation and potential risks of disease transmission.  

V. High-Pressure Treatment Method: Physical Inactivation, Balancing Efficiency and Environmental Protection  

The high-pressure treatment method (also known as the wet rendering method) involves placing animal carcasses in a high-pressure container, introducing high-temperature saturated steam, and treating them at 130–140°C and 0.3–0.4 MPa for 30–60 minutes. Pathogens are destroyed by high temperature and pressure, and the carcass is softened and crushed at the same time. The processed products can be further separated into liquid (containing amino acids and small-molecule organic substances) and solid (bone residue). The liquid can be used for agricultural irrigation (after meeting standards), and the solid can be processed into organic fertilizers or feed additives (after meeting safety standards).  

This method is suitable for all types of animal carcasses, especially for scenarios with high requirements for processing efficiency and environmental protection, such as urban pet harmless disposal and small-to-medium-sized breeding enterprises. Its advantages are short processing cycle, no pollution, and high resource utilization rate; its disadvantage is relatively high equipment investment and operating costs.  

Valuing Harmless Disposal to Fortify the Safety Defense Line  

The harmless disposal of animals is not only a key measure to block the spread of diseases but also an important link in protecting the ecological environment and ensuring food safety. Whether it is breeding enterprises, pet owners, or relevant supervision departments, they should attach importance to the standardized disposal of animal carcasses and avoid random discarding, burying, or incineration. At present, China has issued standards such as the *Technical Specifications for the Harmless Disposal of Sick, Deceased, and Diseased Animals*, clarifying operational requirements for each link. Localities are also gradually building professional harmless disposal centers to fortify the "last line of defense" for public health and ecological security.