Recycling of aquaculture waste returns agriculture to green

Waste is the resource of misplaced place, and it is the "other half" of agricultural production.

The coin has two sides. While meeting the growing demand for meat and egg milk consumption, the annual production of livestock and poultry in the country is about 3.8 billion tons, and the problem of livestock and poultry manure is becoming increasingly prominent. In the Dongting Lake area, individual large-scale farms are free to discharge pollutants, smelling and smelling, and the groundwater ammonia nitrogen exceeds the standard, which seriously affects the health and daily life of the residents...

Yueyang County of Hunan Province is one of the top 100 counties in China. The total output value of aquaculture industry accounts for more than half of the total agricultural output value, and the pollution control pressure is large. Yueyang County is divided into “no-nosing areas, limited-support areas, and suitable areas” to promote the construction of standardized farms and explore the mechanism of harmless treatment of sick and dead animals and poultry. At present, there are more than 60 large-scale farms in the county that have built on-site consumption sites and facilities. More than 100 farmer households and planting bases have carried out planting and breeding cooperation, basically achieving the local consumption of manure.

Yueyang is a microcosm. According to the 2010 General Survey of Secondary Pollution Sources, the chemical oxygen demand emitted by livestock and poultry farming industry reached 12.6826 million tons, accounting for 96% of the total agricultural source emissions; total nitrogen and total phosphorus emissions were 1.024 million tons and 160,400 tons. , accounting for 38% and 56% of the total agricultural discharge, respectively; 24 provinces of livestock and poultry farms (communities) and professional households accounted for more than 90% of the province's total agricultural emissions. Livestock and poultry manure has become a major source of agricultural non-point source pollution.

It is imperative to solve the pollution of livestock and poultry waste. Ma Youxiang, director of the Animal Husbandry Department of the Ministry of Agriculture, said that the pollution problem of livestock and poultry farming is related to the production and living environment of more than 600 million rural residents. It is related to the rural energy revolution, and whether the relationship can continuously improve soil fertility.

Waste is a misplaced resource and the “other half” of agricultural production. The Ministry of Agriculture and other relevant departments actively promote the disposal and resource utilization of livestock and poultry farming. In 2015, the chemical oxygen demand and ammonia nitrogen emissions of livestock and poultry farming decreased by 1.32 million tons and 100,000 tons respectively compared with 2010, with a drop of 11.5% and 15.4%, exceeding the “12th Five-Year” emission reduction target. The utilization level of livestock and poultry manure resources has continued to increase, and the comprehensive utilization rate has increased from 50% in 2012 to nearly 60% in 2015.

Changing biogas, changing fertilizer, and resource utilization are the way out

Unscrew the stove and slam the blue flame. In the Chongming District of Shanghai, the pigs and faeces that the villagers complained of in the past became the necessary gas for households to cook. All the pig manure and urine in the village were transported to the biogas project site for centralized treatment, and the generated biogas was supplied to the villagers. The annual gas production of biogas projects in 10 townships and towns in Chongming District is 2.318 million cubic meters, and the utilization rate of biogas is 70%, which can provide stable gas supply for 4030 households and 8 collective canteens.

Beijing Deqingyuan Agricultural Technology Co., Ltd. is a large chicken farm with more than 3 million laying hens and 212 tons of chicken manure per day. Here, chicken manure is a treasure. After leaving the chicken house, the chicken manure enters the power plant through the staggered vertical and horizontal clearing of the manure belt, and the mixed production wastewater is fermented to generate biogas. The biogas desulfurization and dehydration is converted into electricity by two generator sets and merged into the national grid. Through this “travel”, chicken manure can supply living fuel to 500 villagers in the vicinity, achieving an annual power generation of 14 million kWh and reducing carbon dioxide emissions by 84,000 tons per year.

Energy utilization is a major direction in the treatment of livestock and poultry manure. Ma Youxiang said that the manure is converted into biogas, bio-natural gas or power generation, providing clean renewable energy to the countryside and realizing the use of waste. At the end of 2015, the number of household biogas in the country reached 41.933 million, benefiting more than 200 million people; the biogas project with livestock and poultry manure as the main raw material totaled 110,000, with an annual output of more than 2 billion cubic meters of biogas.

Ninglian Animal Husbandry Co., Ltd. in Qujiang District, Quzhou City, Zhejiang Province, has more than 10,000 live pigs. Qin Tangyong, general manager of the company, said that the company has built a 5000 cubic meter organic fertilizer plant. Through fermentation treatment, pig manure has become a commodity organic fertilizer. The annual processing of pig manure reaches 32,000 tons, and the annual output of organic fertilizer is 15,000 tons. “In the past, pig manure was regarded as a burden on enterprises; today’s organic fertilizer companies have a new profit growth point.”

“Human livestock manure can be made into organic fertilizer, with low investment cost, convenient local use, and an important role in improving soil and promoting crop yield increase.” Ma Youxiang said that the relevant departments have innovated subsidies according to the policy objectives of supporting the protection of cultivated land. The method promotes the soil fertility by promoting comprehensive measures such as organic fertilizer.

Conversion to biogas and bio-natural gas to produce agricultural organic fertilizer is the main direction of resource treatment. Ma Youxiang said that he adheres to the policy of government support, enterprise main body and market-oriented operation, and strives to basically solve the problem of manure treatment and resource utilization in large-scale livestock and poultry farms during the 13th Five-Year Plan period.

Promote upgrading, adjust structure, and realize green development of animal husbandry

Fully realize the resource utilization of livestock and poultry manure, and still face many difficulties in terms of operational mechanism and scientific and technological support. For example, due to restrictions on the total supply of raw materials such as livestock and poultry in the region, continuous stability and transportation radius, the constraints on large-scale production of biogas are obvious. On organic fertilizers, no pigs are planted, and pigs are not raised. Planting and planting separations make it difficult to return livestock manure to the fields.

"In the future, relevant departments should accelerate the construction of modern animal husbandry, promote the green development of animal husbandry, and summarize and promote a number of typical models of livestock and poultry manure treatment and resource utilization." Ma Youxiang said.

Increase the level of aquaculture, and reduce the production of livestock and poultry from the source. Ma Youxiang said that the Ministry of Agriculture promoted aquaculture facilities, standardization of production, harmlessness of manure, and improved standardization of livestock and poultry farming. As of 2015, a total of 3,928 demonstration sites were created. Implement a standardized scale farm (community) construction project for pigs, dairy cows, beef and beef sheep, support the renovation and expansion of farms and the upgrading and upgrading of manure treatment facilities, and improve the equipment level of manure treatment facilities. At present, the scale of livestock and poultry farming has reached 54%, and the proportion of facilities for sewage treatment in scale farms has reached 50%.

Continuously optimize the structure to achieve a combination of agriculture and animal husbandry. The Ministry of Agriculture has accelerated the transformation of pig breeding in the southern water network area and guided the transfer of pig breeding to the main corn producing areas and areas with large environmental capacity. We will start the implementation of the pilot project for the breeding of dairy farming in the county, and support the construction of a waste-free treatment facility and a forage base.

Ma Youxiang said that accelerating the treatment and resource utilization of livestock and poultry farming is not only to respond to the eager expectations of the masses, but also to overcome the contradiction between the excessive use of agricultural resources and the lack of waste utilization, so that agriculture can return to green.