Design of Ecological Engineering for Combination of Agriculture and Industry


A design of ecological engineering for combination of agriculture and industry Jingsong Yan(1), Hanting Shen(2), Yanqie Zhang(3)

(1).Institute of Geography & Limnology, Academia Sinica, Nanjing 210008, Jiangsu, China; (2). Baoyin County People's Congress, Baoyin 225800, Jiangsu, China; (3). Environmental engineering Division, China University of Mine & Technology, Xuzhou 221008, Jiangsu, China.

An systematic design for reduction, recovery, regeneration, reuse and recycle of waste in most processes in a series of agricultural and industrial production has been practiced to establish an ecological engineering approach in combination of agriculture and industry in Baoyin County, China. A field of more than 1,500 ha is arranged to produce 20,000 tons of corn. Corn is used as the raw material to produce corn oil, protein, and starch. The starch is further used to produce glucose and gluconiclactone in a local pharmacy factory. The cob of maize, a waste of the processing is used to produce furfural in another factory. Another waste, the stalks of maize, serves as the main fodder for cows, through ammonation. The suspended protein and starch in the wastewater from a pharmacy factory are recovered by adding a nonpoisonous coagulant and by helical flow method, in order to reduce COD, BOD and nitrogen in the waste water. The recovered protein and carbohydrate are used as a fine feed for pigs, domestic fowls and cultured fish in the local farms. The dissolved glucose and nutrients in the wastewater is further used to produce Saccharomycetes and protein as additive feed in the local husbandry farms. The wastewater is then treated and utilized by planting water hyacinth and hydroponics cultured vegetables in a 4 ha pond. These plants can convert and remove 1,422 kg/ha of nitrogen, 232 kg/ha of phosphorus, 178 kg/ha of sulfur and much organic material into 900 t/ha of green fodder and vegetables a year. The wastewater finally flows into the integrated fish culture pond of 5 ha. This fish culture includes fish-cum-duck, fish-cum-geese and several fishes with different feeding residential habitat. This will result in a multi-layered and step-wise utilization of the waste of most trophic links of the food web and to bring the potential of spatial niche into full play in the pond ecosystem. In winter, the pond mud should be removed to fertilize croplands. The wastewater after the treatment and utilization can be reused for industry. The great amount of excrement from pigs, cows, and domestic fowls should be used as the raw material for biogas generation in a biogas fermentation system. The solid sludge from biogas fermentation can be used as additive feed for pigs and fishes and as the culture medium for the mushrooms. The residue can be used as the main culture medium for earthworm. The production of cultured earthworm has attained 75-225 t/ha, as food for duck, pig and specially for the soft-shelled turtle with high economic value.

Earthworm is also a traditional Chinese medicine. By the latest invention, an anticoagulant for effective treating cerebral and coronary thrombosis, varix, and rheumatic arthritis has been extracted and purified. The earthworm fresh castings contains 22.5% of raw protein and some growth promoting hormone. It can be mixed with some grain in certain ratio to produce mixed feed for pigs. With this feed, experiment results show an average annual increasing body weight of pig, chicken and fish (Tilapia) is 11.37%, 7.2% and 45% respectively in comparison to the control. The earthworm dung can directly fertilize the maize field, and can be mixed with chemical fertilizer to produce granulated fertilizer. They can prevent quick loss of ammonia, potassium and quick fixation of phosphorous by soil. It makes multi-step use of substance within this system. It means the remaining part or waste of a link would be the raw material is another link and so does link by link on the analogy. This ecological engineering would reach synchronous development of ecological, environmental and economical benefits by less or no waste and pollution and full use of resources.

Keywords: Design, combination, agriculture and industry, corn process, waste recycle and reuse

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