What are the relevant standards for sludge aerobic composting?

Ambient temperature, humidity, oxygen concentration, etc., are important criteria in the aerobic fermentation process.

1. Temperature. Temperature is an important factor influencing microbial activity and the composting process. For the composting process, temperature is the apparent manifestation of its state.

All process parameters are controlled in order to achieve the fastest increase in the temperature of the compost, the maintenance of the appropriate compost temperature and the smooth decline during composting. Because the high temperature of the compost can kill the pathogenic bacteria in it, the organic matter degradation is fastest within the appropriate temperature range of the compost, and at the same time, the removal of water and the decrease of the compost temperature under the appropriate circumstances will end the compost.

The compost went through 18 days.

From the perspective of the temperature change of the compost, the compost has gone through a complete stage of heating, constant heating and cooling. From the beginning of fermentation, the temperature of the pile continued to rise, from 17 to 55 in 1-7 days. Maintain a constant temperature of 55 60 for about 18 days; The reactor temperature then drops to 30. After 24 days, the temperature of the reactor remained stable, and the temperature continued to be monitored, and no increase in temperature was observed.

Indicates that the compost has reached a stable level.

During the composting process, parasites and pathogenic bacteria are killed, and the number of bacteria is measured at 12 days, and the results are shown in Table 4. Experiments have shown that after three days of 55 high temperatures, sludge compost can kill most of the pathogenic bacteria, which meets the hygienic indicators of compost and can be applied safely.

Moisture content. In composting ecosystems, water content is an important physical factor. Water is indispensable for the decomposition of organic matter and the growth and reproduction of microorganisms.

The main functions of water in compost are:1dissolves organic matter, participates in the metabolism of microorganisms; 2.

When the water evaporates, it takes away the heat and plays a role in regulating the compost temperature. The amount of moisture in the compost raw material directly affects the speed of the aerobic compost reaction, affects the quality of the compost, and even relates to the success or failure of the aerobic composting process, so the control of the moisture in the compost is very important. During the composting process, sludge samples are taken and dried in an oven of 105 110 for 4 hours, and the weight lost in drying is weighed as the moisture content.

Sludge Treatment and Disposal Technical Policy for Urban Sewage Treatment Plants stipulates:

1. Sludge agricultural use shall be subject to site environmental impact assessment, and shall be approved by the relevant administrative department of environmental protection before it can be implemented. The sludge disposal party must sign a contract with the sludge applicator, and the sludge disposal party is responsible for the short-term or long-term negative effects of sludge farming.

2. The sludge must be stabilized and harmless before agricultural use, and the degradation rate and health indicators of organic matter in the sludge must meet the relevant national standards. Special attention should be paid to the content of heavy metals in the sludge, and when the content of any heavy metal in the sludge exceeds the standard, it shall not be used for agriculture.

3. Sludge should be used as base fertilizer for agricultural utilization, and the application rate of sludge should be controlled under the safe application rate, and sludge should not be used for agricultural use in the crop growth or harvesting season.

4. Strict application, management, testing and monitoring systems should be established in sludge application areas, and relevant competent departments should regularly monitor the relevant indicators of soil, groundwater, surface water, crops and other relevant indicators in the area to ensure the safety of sludge agriculture and promote the sustainable development of agriculture.

The Best Available Technical Guidelines for the Prevention and Control of Pollution from Sludge Treatment and Disposal in Urban Sewage Treatment Plants stipulates:

Sludge aerobic fermentation process type.

1. Stacked aerobic fermentation.

Strip stacking aerobic fermentation usually adopts the fermentation method of open air forced ventilation, and the mixed materials treated by the pre-treatment section are stacked on the ground after anti-seepage treatment to form a long strip stack with trapezoidal section. Strip stacking aerobic fermentation is divided into two processes: static and batch dynamic.

Static aerobic fermentation refers to laying an air supply duct system on the ground where the sludge mixture is stacked, and providing the required oxygen for the aerobic fermentation process through forced ventilation or air extraction.

Intermittent dynamic aerobic fermentation refers to the use of wheeled or crawler type equal turning (throwing) equipment, which is regularly turned over to make the mixed material fully in contact with the air and maintain the oxygen required for the aerobic fermentation process.

At present, the strip stacking aerobic fermentation process combining static forced ventilation and regular turning of the pile is usually adopted.

2. Fermentation tank (pool) aerobic fermentation.

Fermentation tank (pool) type aerobic fermentation refers to the setting of a number of fermentation tanks in the workshop, the bottom of the tank is provided with air supply pipes and drainage pipes, and the top of the tank wall is set up with a track for mechanical transfer of the pile for turning the pile and turning the pile regularly. The typical process of fermentation tank (pool) aerobic fermentation is the sun shed fermentation tank.

The fermentation tank of the sun shed refers to the use of the light transmission and thermal insulation performance of the sun shed to increase the temperature in the fermentation tank. A ventilation duct system is installed at the bottom of the fermentation tank to ensure the oxygen required for the aerobic fermentation process by means of forced ventilation.

The requirements and calculations for composting can be found at:

CJJ131-2009 Technical Regulations for Sludge Treatment in Urban Sewage Treatment Plants

For the index requirements of mud, please refer to:

CJ T309-2009 Sludge Disposal in Urban Sewage Treatment Plants Agricultural Sludge

Do you want the parameters in the composting process or the standards to be met after composting?

Summary. Hello pro , between 200 and 800 mg l. The chemical oxygen demand (COD) of a good compost product can vary widely, usually depending on the amount and quality of organic matter in the finished compost.

Chemical oxygen demand (COD) is a method of determining the content of organic pollutants, which refers to the amount of oxygen required by oxidized organic matter under certain conditions. The content of organic matter in the finished compost is high, and the chemical oxygen demand is relatively high; Conversely, if the organic content is less, the chemical oxygen demand is also lower. Therefore, the COD of good compost products has a certain fluctuating range, but it should generally be kept between 200 and 800 mg l.

Through reasonable selection of raw materials, scientific production technology and strict quality standards, the chemical oxygen demand of compost products can be controlled as much as possible to ensure the quality and safety of products.

Hello pro , between 200 and 800 mg l. The chemical oxygen demand (COD) of a well-maintained compost product can vary greatly and usually depends on the content and quality of organic matter in the finished compost product. Chemical oxygen demand (COD) is a method of determining the content of organic pollutants, which refers to the amount of oxygen required for oxidized sheltered organics under certain conditions.

The content of organic matter in the finished compost is high, and the chemical oxygen demand is relatively high; Conversely, if the organic content is less, the chemical oxygen demand is also lower. Therefore, the COD of good compost products has a certain fluctuating range, but it should generally be kept between 200 and 800 mg l. Through reasonable selection of raw materials, scientific production technology and strict quality standards, the chemical oxygen demand of compost products can be controlled as much as possible to ensure the quality and safety of products.

What is the moisture content and C/N ratio in a fully decomposed compost product.

The moisture content and C/N ratio of fully decomposed compost products can be affected by a variety of factors, such as the type of raw materials, the treatment method of the compost, etc. In general, the moisture content of a fully decomposed compost product should be less than 30%, because too high a moisture content of a pure stove may cause inhibition of microbial activity in the compost, which may affect the quality of the compost. The C/N ratio should be at 25:

Between 1 and 30:1, this is because too high or too low a carbon to nitrogen ratio can affect the stability and efficiency of the compost. It should be noted that different compost products may have different requirements for moisture content and carbon to nitrogen ratio, and the specific values need to be determined according to the actual situation.

In addition, the quality of compost products is also affected by other factors, such as pH value, nutrients, etc., so scientific management and monitoring are required in the production and use process to ensure the quality and effect of compost products.

1) Reasonable ingredients, local materials;

2) Keep the pile temperature above 60 and should not be less than 1d;

3) Ensure that all parts of the compost can be effectively disinfected;

4) Take measures to prevent people from being polluted.