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2015-R2 Manure treatment under Chinese conditions

2018-8-14 15:18:11 Comments:0 Views:506 category:Project Introduction

5.1. About Principle Investigator

Professor Dong Renjie engaged in production and evaluation of biomass resources, artificial wetlands, indoor air quality monitoring and Africa agricultural development, biogas and biomass stove standardization since 1985, having achieved highly academic success. With outstanding achievements in the field of agricultural engineering and environmental engineering, Prof. Dong becomes the member and Secretary General in many famous conferences. Since 2005, he has been the chairman for Forum of Renewable Energy Promotion in Developing Countries (FREPDC) since 2005, also been the chairman of 2015International Composting Conference (Second Branch). Prof. Dong has published more than 200 academic papers so far, authorized 21 patents and carry out 30 projects. With abundant experience and leading interdisciplinary research teams, he has won lots of prizes in science and technology.

5.2 Objectives of the study
Sustainable Dairy Manure Management (SDMM) project deals with the most widely existing problem on dairy farm, to minimize pollution for dairy farms and surroundings, through appropriate and optimal integration of different manure handling technologies, including aerobic composting, anaerobic digestion, and effluent gases and liquids treatment. The overall goal of SDMM is to provide appropriate strategy and best technical recommendations for sustainable dairy manure treatment in China.

5.3 Main report of the research
5.3.1 Questionnaire Survey
According to many researches, most of cattle manure is treated in an Aerobic Compost (most as air drying) way after stockpiling, which is adopted at 143 dairy farms of 189 research sites in questionnaire. Apart from that, there are 37 dairy farms where survey data is absented after the feces separation. And only 9 farms are adopting the system of both manure separation and compost. According the questionnaires, most farms use mechanical collection system such as Scrapper and cleaning truck. And also, Artificial collection method is employed at 61 cattle farms, while only 18 farms artificial auxiliary machinery collection.

5.3.2 Field investigation
We have been several dairy farms and got the fresh materials to catch a sight of the overall situation in China.
(1) Saibei Modern Farming Group is located in Zhangjiakou City, Hebei Province. On 19 September, 2015, researchers from CAU visited Saibei farm which has 12000 heads cows. The biogas fermentation engineering technology is adopted in farm to treat manure.
(2) YingBo Dairy Farming Co., Ltd. is a wholly-owned subsidiary of Bright Food Group Co., Ltd. It’s a demonstration of modernization and holds 800 cows. Manure treatment center covers an area of 37500 m2. Oxidation pond covers an area of 21500 m2. There are two kinds of treatment measures, BRU (Bedding Recovery Unit) and biogas project. Figure outlines the operations that take place in manure treatment.
(3) Dairy industry is the dominant industry in Ningxia Hui Autonomous Region due to efficiently large-scale cattle breeding, four typical farms have been visited in Yinchuan City.
(4) ShenChi NongMu Co.,Ltd. in Tianjin holds a designed scale of 967 lactating cows, 249 cows (experiencing the period of milking stop), 241 calves, young cattle and bred cattle is 934 heads in total. There is about 91.6t dung output per day at farm and 61 m3 sewage from cows.
(5) Datong Sifang Dairy Farm is jointly set up by the Datong Dairy Co. Ltd. and Yangjiayao village, which is the largest farm in Shanxi and bears the fame of national dairy industry technology system of Datong comprehensive experimental station (2011-2015). There are 4300 heads cattle. According to water quality, ecological recycling mode concerns “Scrapper+ Solid-liquid Separation+ Oxidation Pond”. The main units include “scrapper with water” collection system, “grid clearing and solid-liquid separation equipment” pretreatment system, oxidation pond system to treat sewage, manure slag treatment system to obtain bedding materials.
(6) Qutou Farm in Beijing is a large cattle Farm. Through field investigation and sampling analysis, solid concentration of the manure sample in cowshed reaches 16.8%. After separation, the liquid manure was storage in a pond and the solid was further dried.
(7) Hebei Xinglong County Shuangfeng forestry and animal husbandry farm (Shuangfeng farm). The Recycled pattern at this farm is the cultivation with breeding. On the one hand, fertilizer produced from 300 high-quality dairy cattle feces to cultivate trees each year and ensure the basic nutrition of tree growth. On the other hand, deciduous trees every year also ensures 4 months of coarse fodder supplies for cattle. Through field investigation and sampling analysis, solid concentration reached 10.4%, dry dung cleaning way. At Shuangfeng farm, cowshed manure solids concentration is 10.4%, o analysis of solids concentration n beddings sampling is 15.0%. After centrifugal separation, solid concentration increases to 22.2%.

5.3.3 Sampling analysis
In order to reduce nutrient losses, legal nutrient application rates for nitrogen and phosphate have to be established and respected for different crops on different soils in different Chinese climate zones. Especially on sloping and bare land, manure runoff has to be prevented. Chemical analyses of the nutrient (N and P) contents of cattle slurry, anaerobic digester effluent, solid and liquid fractions and other manure products, is essential for the calculation of an accurate crop specific fertilization rate, the calculation of how much manure can be adequately utilized per mu (15 mu = 1 hectare). Insufficient fertilization rates will produce insufficient crop yields and excessive fertilization rates will cause nutrient losses to the environment. Unavoidable nitrogen losses following manure application (approx. 40-80 % of total N, depending on manure type and application technology) can be compensated with chemical nitrogen fertilizer.

5.3.4 Summarized patterns of manure treatment and utilization in China

(1) Cultivation with Breeding. Dry Manure Collection technology is adopted to get aerobic compost. Sewage is treated by anaerobic digestion or oxidation pool. If up the standard, manure and treated water could be used in agriculture land.

(2) Recycling. Water is saved through the total process. Sewage is conveyed by conduits. And rain sewage diversion and solid-liquid separation system are adopted to save water. Treated sewage is mainly used for flushing excrement groove or fences. Solid manure is utilized through compost, edible fungus matrix monk, bedding material preparation and fuels. This model is applicable to the economically developed areas with less planting around dairy field.

(3) Discharge on Standard. After anaerobic fermentation and aerobic treatment, if the Dairy wastewater could up to the national emission standards, then discharged to the environment or to urban sewage pipe network system, and mixed with urban sewage to get subsequent processing. The model consists of pretreatment, anaerobic treatment, aerobic treatment, sludge treatment, biogas purification, storage and use of composition. This model is applicable to the economically developed areas with less planting around dairy field.

(4) Centralized Treatment. In intensive and large-scale breeding communities or regions, the surrounding farms manure or sewage is collected to get centralized treatment. Due to sharing of one set of equipment, input and cost is decreased while cost for transportation and storage facilities increases. And, it’s necessary to prevent regional health and safety risks.

5.3.5 Manure Treatment:Case Study

(1)Aerobic Compost

Aerobic composting technology is an effective solution to treat animal waste. In this paper, an excellent large-scale project in domestic cattle farming is exampled. Dongying Earth Biological Technology Co. Ltd. It’s a project which ensures an annual output of 20,000 tons of organic fertilizer, bio-organic fertilizer and organic-inorganic compound fertilizer production. Bio-organic fertilizer production process mainly concern as follows: Pretreatment of raw materials, The First Fermentation, Aging and Fertilizer. Aerobic fermentation process is in raw organic manure fermentation, then mixing of organic fertilizer and inorganic to get powder and granular of compound fertilizer. Ingredients are charged automatically by computer, and granulation is from pressure grain and grinding process by flat molding machine. 

(2) Anaerobic Digestion

Beijing Sino Farm Co., Ltd. is located in southwest of Beijing and holds 4400 heads cow, of which are 2000 heads lactating cows with casual feeding pattern. Manure and Sewage treatment process is Manure Collection by scrapper and transportation by truck. After solid-liquid fraction separation, solid part is transported to manure fermentation processing center. Although there is lack of safety inspection, organic fertilizer is very popular among farmers in vicinity area. The liquid manure is used for biogas production, while biogas is not stable because of un-purity. While emission of biogas is unwanted, part of biogas is directly discharged into air. And biogas slurry partly is applied to arable farm or agriculture land, the rest almost unsaleable due to the difficulty of transportation.


5.4 Conclusion

Manure management plays a key role in the sustainable development of the dairy industry in China. Results obtained in this project indicated that the pollution control, energy recovery, and nutrient utilization in dairy manure should be improved for China dairy farms. Further research and extension should be aimed at increasing the manure nutrient efficiency. The first work should be the measurement of the gas emission in dairy manure and then to determine which step to control the pollution for manure treatment process. In addition, anaerobic digestion was widely used to recovery energy from diary manure and the use the digestate as a organic liquid fertilizer, the suitable biogas technology need further research for modern farms. Fortunately, both the gas emission measurement and the anaerobic digestion technology were supported in SDDDC Project-2016.




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