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Preparation Method of Dairy Cow Manure Organic Fertilizer


The dairy farming industry is providing a large amount of high-quality and safe raw milk for dairy processing to meet people’s nutritional and health requirements. While promoting social and economic development, it also generates a large amount of organic solid waste and high-concentration organic wastewater.

Cow manure is rich in organic matter and plant nutrients and is a good organic fertilizer resource. However, a large amount of sewage manure is returned to the fields without any treatment. Due to the unreasonable nutrient mix, some nutrients are wasted. Secondly, the direct application of sewage manure with large amounts of nutrients and various elements will also cause crops to grow elongated, lodging, mature late or immature, resulting in reduced yields. It can even poison crops, especially seedlings, causing widespread death.

If sewage is directly discharged into nearby water bodies, it will have direct or indirect impacts on water bodies, soil, atmosphere, human health and ecosystems. Therefore, finding scientific and effective measures to deal with cow manure has become an urgent problem for the dairy farming industry.

Problems with handling of cow manure

The biggest problems in the treatment and utilization of sewage manure in intensive dairy farms are the high moisture content and stench of the manure. In addition, large amounts of ammonia nitrogen are easily lost during the treatment process. Manure contains a large number of pathogenic microorganisms and weed seeds, which pose a threat to the environment.

Therefore, harmlessness, resource utilization, and comprehensive utilization are the basic directions of its treatment. The resource processing of cow manure usually involves collecting fresh cow manure using mechanical or manual methods. Plant nutrients such as nitrogen, phosphorus, and potassium are retained to the maximum extent through physical (cow dung drying machine), chemical, or biological methods and in accordance with a certain process flow. Thereby removing harmful substances or reusing them as feed or other uses.

Technology and methods

Dewatering process

Use fuel, solar energy, and wind energy to process cow manure. Not only can it greatly reduce the moisture content of feces, but to a certain extent, it can also achieve deodorization and sterilization effects. The dried cow manure reduces environmental pollution and can be processed into granular fertilizer or livestock and poultry feed. When the moisture content of sewage is high (≧80%), solid-liquid separation can also be achieved through mechanical dehydration. After reducing the moisture content of the sewage, it can be used as roughage or protein concentrate feed. It should be noted that if the moisture content exceeds 90%, a slope screen manure separator needs to be used.

Anaerobic fermentation to produce biogas

The sewage content of dairy farm sewage has a high moisture content (about 85%) and is a good raw material for anaerobic fermentation biogas. Moreover, the by-products of biogas are biogas residue and biogas slurry, which can be used as fertilizers, feeds and plant growth promoters. However, the power generation rate of biogas projects is very low, the anaerobic fermentation cycle is long, and it occupies a large area. The one-time investment is too large, the operation management technology is difficult, and the dehydration and drying effect is poor. Intensive livestock and poultry farms are far away from residential areas, making the utilization of biogas difficult.

Aerobic composting

Aerobic composting is currently the most researched and widely used organic waste treatment method. Aerobic high-temperature composting can eliminate odor, and kill pathogenic bacteria, parasite eggs, and weed seeds, making it harmless and stable. Aerobic composting initially adopts the method of retting, which can be matured by heaping at natural temperature. This method is low-cost, but it occupies a large area, takes a long time to process, and is more susceptible to weather effects.

At the same time, uneven fermentation occurs due to the low number of turning piles. Aerobic composting uses the fermentation of natural microorganisms under certain temperatures, moisture content, carbon-nitrogen ratio, and ventilation conditions. A microbiological process that artificially promotes the conversion of degradable organic matter into stable humus. Aerobic composting technology shortens the compost fermentation time from more than 100 days for natural composting to the current 30-50 days. Rapid ripening can be achieved in even a shorter period.

After composting, organic solid waste is rich in humus and plant nutrients such as nitrogen, phosphorus, and potassium. It becomes a high-quality organic fertilizer and a good soil quality improvement. At the same time, the fermentation temperature of composting is high, generally between 55°C and 65°C. It can even reach above 70℃, dehydrate quickly, and can also kill pathogenic bacteria, parasite eggs, and weed seeds. The deodorization effect is good, and the purpose of harmless and resource treatment and utilization is well achieved.

Technical solutions 

  • 1000-2000 parts of cow manure, 200-500 parts of straw, 1-3 parts of compound fermentation bacteria, and 0.5-2 parts of compound fermentation enzymes.
  • The compound fermentation bacteria include two or more of the Trichoderma group, Aspergillus group, Enterococcus faecalis, photosynthetic bacteria group, lactic acid bacteria group, yeast group, filamentous bacteria group, actinomycete group, Bacillus group, and nitrogen-fixing bacteria group. A mixture of two or more.
  • A mixture of two or more of ligninase, laccase, protease, amylase, peptidase, cellulase, hemicellulase, maltase, sucrase, oxidation-reductase, and catalase.

Preparation method of dairy cow manure bio-organic fertilizer

  • Preparation of pre-fermentation materials: dry the cow manure crush it, and crush the straw. Mix the crushed cow manure and straw evenly.
  • Stacking treatment: The pre-fermentation materials are stacked, and then the composite bacteria and compound fermentation enzymes are evenly sprayed on the fermented materials after stacking. Then cover the fermentation material with waterproof material to avoid being exposed to rain.
  • Fermentation: Fermentation time is 5-10 days. During the fermentation period, oxygen is regularly introduced into the fermentation material. Control the temperature of fermentation materials in the fermentation pile. When the temperature reaches above 50°C, the fermentation materials are turned over.
  • Aging: The fermented materials remain in a pile state and continue to be placed. No more oxygen and temperature control, aging for 2-5 days.

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