In addition to producing a large amount of chicken and egg, the modern intensive chicken industry also produces a large amount of chicken farm waste – chicken manure.
Chicken manure is the main source of waste in the chicken farm and the largest source of pollution near the chicken farm.
Chicken manure contains a large number of pathogenic microorganisms, heavy metals such as Cu, Zn, Mn, etc. And emits a variety of harmful gases such as NH3, H2S, etc.
The chicken manure site is also the main source of breeding for mosquitoes and flies in the chicken farms and the concentration of rodents and birds.
A 650,000 laying hens produce nearly 10 tons of fresh chicken manure every day. If not processed in time, this will cause serious pollution to the chicken farm environment.
Reasonable chicken manure treatment and application is the only way to solve the pollution problems, achieve sustainable development of the chicken industry, develop green poultry products, and increase the efficiency of chicken raising.
At present, the treatment methods of chicken manure mainly include drying, aerobic fermentation, biogas treatment, etc. The quick chicken manure drying method can effectively remove a large amount of water, kill pathogenic microorganisms and reduce nutrient loss. Also, the chicken manure after drying is easy to store, sell and transport, which is convenient for the use of chicken manure in different places and solves the local environmental pollution problem.
Why drying chicken manure
Chicken manure is composed of intestinal and ureteral excretions. The main components are the parts of the feed that are not digested and absorbed, metabolites in the body, digestive tract secretions and exfoliated mucosa, intestinal microbes and their decomposition products. The chicken faeces actually collected also contain fallen feathers, sprinkled feed and broken eggs. The broiler chicken manure is mainly a mixture of chicken manure and litter.
After the chicken manure is dried, the microorganisms and parasites and their eggs can be killed. At the same time, the chicken manure can no longer have an obvious odor and is easier to store and utilize
The value and usages of the dried chicken manure
Used as fertilizer
The main usage of dried chicken manure is as fertilizer. Currently, this application accounts for more than 95% of the total chicken manure. Chicken manure is rich in nutrients necessary for plants such as N, P, K, etc. It is a high-quality organic fertilizer in plant production, which is superior to other livestock manure.
According to the measurements, the contents of N, P and K in fresh chicken manure are 1.3%, 1.1% and 0.6%. The amount of chicken manure used in production is determined on the basis of nitrogen balance. After drying or aerobic fermentation, the chicken manure is soft, odorless, and without pathogenic microorganisms, which can be widely used in flowers, pollution-free vegetable cultivation and soilless cultivation.
Used as a feed
As a feed, it is a direction for further utilization of chicken manure in the future, especially in the feed of herbivorous livestock, pigs and aquaculture.
The nutrient content of chicken manure is shown in the table below.
| type | Total energy (MJ/KG) | Digested energy (MJ/KG) | Crude protein (%) | Ash (%) | Ca (%) | P (%) | Lysine (%) | Methionine (%) |
|---|---|---|---|---|---|---|---|---|
| Broiler manure | 14.42 | 7.94 | 25 | 29 | 8.5 | 2.5 | 0.5 | 0.09 |
| Laying hen manure | 14.63 | 9.2 | 30 | 17 | 2.4 | 1.9 | 0.6 | 0.1 |
Compared with other livestock, the chicken feed has a high nutrient content. Because the feed stays in the digestive tract for a short period of time, the chicken manure produced has a higher nutrient content and has potential feed value.
It can be seen from the table that the crude protein content of chicken manure is higher. However, about one-third of them are non-protein nitrogen, such as urate, ammonia, urea, etc. Non-protein nitrogen cannot be used by single-stomach livestock, but the ruminants can, so cattle and sheep get higher digestive energy values to use chicken manure as a feed.
Besides, chicken manure is rich in minerals, which can meet the needs of cattle and sheep.
Therefore, chicken manure is a good source of feed for ruminant livestock.
Dry chicken manure can be added up to 15% in beef cattle diet, 12% for dairy cows, 20-25% for reserve cattle, and 15% for fattening sheep, with no adverse effects on production. Due to its low true protein and metabolizable energy content, dry chicken manure is also suitable for 1.5-2% in pig diets, which can be up to 4%. In addition, the practice has proved that use chicken manure to feed fish can achieve good economic benefits.
Chicken manure quick drying with rotary drum dryer
Chicken manure is usually dried by the rotary drum dryer. For economic considerations, coal is often used as a heat source for this drying process. High-efficiency combustion furnace produces clean high-temperature flue gas, which is used as a heat medium to dry the manure. It is a kind of drying equipment with high thermal efficiency.
The drying process
Collection
Chicken manure should be properly collected before drying.
Not all chicken manure is suitable for quick drying.
First, the moisture of raw chicken manure is required to be less than 70%. The chicken manure with too much moisture has low drying efficiency, requires more heat energy and high running cost.
When the chicken manure is mushy, the dryer does not work properly. In order to effectively control the moisture content of chicken manure, it is necessary to prevent the water tank from leaking, and it is necessary to install a nipple type drinker.
The manure cleaning of the chicken house can be done mechanically or manually.
Regardless of the type of cleaning, it is necessary to avoid washing with water to avoid increasing the humidity of chicken manure. Chicken manure should not be placed in the chicken house for too long. The chicken manure should be dried for a few days according to the drying capacity of the dryer.
If the dried chicken manure is to be used as feed, it is best to dry the chicken manure the same day when produced. In the process of chicken manure accumulation, a large amount of protein is decomposed into non-protein nitrogen by microorganisms in chicken manure, which makes the feed no use value to pigs and poultries. For ruminants, an increase in non-protein nitrogen limits their use in feed and decreases palatability. In addition, chicken manure is stored for too long, and it produces ingredients that are toxic to livestock and poultry such as nitrite.
Transportation
The collected chicken manure is transported to the septic tank by truck and then fed to the dryer inlet via a belt conveyor. The septic tank should be built with a rainproof roof and repair drains to prevent rainwater from entering. The capacity of the septic tank should be matched with the chicken manure dryer.
Drying
Before the rotary drum dryer is in operation, it should be maintained and Ignition for preheating. When the furnace temperature reaches 300 degrees Celsius or above, the round drum starts to rotate, and at the same time, the chicken manure transport device is turned on. The manure then is sent to the dryer.
The chicken manure is transported by the conveyor to the top of the dryer and falls into the drying drum. When it falls, it is broken by the crushing device installed on the central shaft of the dryer. At the same time, it is rapidly dehydrated and dried under the action of high temperature gas flow.
Finally, the dried chicken manure is discharged from the discharge port. The dried chicken manure is uniform and fine particles with a moisture content of 12-20%. The moisture content of the dried chicken manure can be adjusted by controlling the rotational speed of the drying drum.
After the fresh chicken manure is dried, there is a light soybean flavor, which is suitable as a feed. The moisture content in the dried chicken manure is adjusted by the temperature of the fire and the rotation speed of the drying drum.
Packaging and storage
The dried chicken manure enters the finished product warehouse and is packed after being cooled. Dry chicken manure should be strictly protected from moisture, the bag should have a moisture-proof inner membrane, the ground should be dry, and the warehouse should be ventilated.
The chicken manure that meets the above requirements can be stored for a long time, and the fertilizer efficiency will not be reduced. However, dry chicken manure as feed should be used as soon as possible to prevent nutrient loss.
The benefit and prospect of chicken manure drying
The main cost of the chicken manure drying equipment is coal, electricity, and labor.
To produce 1t dry chicken manure with a moisture content of 20%, the required coal is 0.35t (including coal for workers’ living), and 60 kilowatt hours of electricity (including plant ventilation, lighting power and workers’ usage).
Dry chicken manure is currently used mainly as a fertilizer and is popular with vegetable growers. The wet chicken manure is left unattended, difficult to handle, and causes environmental pollution. Chicken manure quick drying has great social and economic benefits.
Dry chicken manure as a fertilizer is easy for storage, transportation, and has a long-term fertilizer effect, it is not easy to cause soil compaction, suitable for growing vegetables and raising flowers. Dried chicken manure as a good feed source for ruminant breeding and aquaculture is the future development direction of chicken manure drying.