Path: utzoo!utgpu!watmath!iuvax!bionet!finujo.bitnet!TENHUNEN From: TENHUNEN@finujo.bitnet Newsgroups: bionet.technology.conversion Subject: VJ Composting System: (1) The composting processes Message-ID: <8904032138.AA02939@net.bio.net> Date: 3 Apr 89 13:51:00 GMT Sender: daemon@NET.BIO.NET Lines: 153 ************************************************************* *HEAT RECOVERY COMPOSTING PLANT IN AN INTEGRATED PRODUCTION* *OF COMPOST, EARTHWORMS, FISH BREED, GREENHOUSE, AND OUTDOOR* *CULTURES: a demonstration project of VJ-Komposteringssystem* *AJ, sponsored by EC. Part I: The composting processes * ************************************************************* 1 INTRODUCTION ============ This project has the aim to achieve maximum utilization of the organic waste projects which are a potential energy source and raw material for compost products. The compost products are tested for greenhouse and outdoor use before it is sold as a declared compost. Also, the aim is to demonst- rate less-pollution problems with agricultural and other or- ganic wastes. The plant is built in the Danish parish of Aulum-Haderup in an area of 10 hectares in the vicinity of the factory of Praeriemuld A/S. Many fur and poultry producers, with a large surplus of animal manure, are located in the area, and they are very interested in the delivery of manure to the plant. Most of the income will be brought by an eel breeding plant. The wastewater produced by this plant will be treated in the water-hyacinth greenhouses. The sludge will be treated with the separated slurry in an anaerobic filter. Part of the effluent from the filter will be totally treated by the water-hyacinths, and the other part will be used for land application. 2 DESCRIPTION OF THE SOLID MATERIAL LINE ====================================== 2.1 Receipt of the organic substrates --------------------------------- At the plant, the different substrates (poultry and fur ma- nure, straw, chips, bark, and peat, or the like), will be received and stored separately under a cover. 2.2 Substrate mixtures ------------------ The substrates will be analyzed in a laboratory for relevant physical and chemical properties, and the desired mixtures will be formulated by means of a computer. The plant will be scaled for the treatment of ca. 2.630 tons of organic substrate per year, corresponding to ca. 7,2 tons (ca. 10 cubic meters) per day. 2.3 Composting heat plant (CH plant) -------------------------------- The substrate mixtures will be composted for 5 - 7 days in a composting heat plant. The main characteristics of the plant are as follows: 1) The composting process will be fully controlled with a subsequent high rate of composting. In 5 days, ca. 30 per- cent of the substrate solids will be converted into carbon dioxide and water. 2) The plant will be a closed system, where the whole bio- mass will be exposed to a temperature of 60 degrees Centi- grade for 5 days, so that the substrate will be sanitized for pathogens, parasites, and weed seeds. 3) Ca. 70 percent of the biologically produced heat energy can be exploited by the heat exchanger system, while the rest will be lost with the exhausted air. 4) The exhausted air will have an increased content of carbon dioxide, and after a purification this air can be utilized for the heating and carbon dioxide enrichment of the greenhouse atmosphere. 5) Nitrogen loss during the process will be limited due to process adjustment and the collection of evaporated ammonia to the water of the air scrubber in connection to the heat exchanger system. In this project, the heat produced by the CH plant will be used for the heating of the greenhouse, eel culture, vermi- culture, and for the heating of the connected building con- taining laboratory, packing equipment, administration, etc. The carbon dioxide formed will be utilized for the promotion of plant growth in the greenhouse, while the ammonia-en- riched water will be utilized as as a liquid fertilizer for outdoor vegetables. When the CH plant will receive ca 7.2 tons of substrate per day, corresponding to ca. 10 cubic meters per day, and the plant will have the treatment time of 5 days, a plant volume of 50 cubic meters will be necessary. The plant will produce ca. 3.7 tons of fresh compost per day (1,350 tons per year), and the power will be 50 kW (ca. 38 tons of oil equivalent per year). Energy consumption of the plant for the structuring and aeration of the material will be 6.5 kW (ca. 5 tons of oil equivalent per year). 2.4 Curing ------ The fresh (raw) compost coming from the CH plant don't be sufficiently stabilized (mature) for use as a growth medium for plants, and it can cause damage to the plants or rest- raint of germination. This compost must therefore be cured, partly by windrow composting and partly by vermicomposting. 2.41 Windrow composting One-third of the fresh compost (450 tons per year) will be stabilized in windrows. The stabilization process will take place indoors in 4 - 8 weeks, depending on the wanted matu- rity index wanted for the compost. In this period the com- post will be turned, structured, aerated and moistened se- veral times by means of a turning machine. Fresh and cured compost will be removed by means of a front-end loader. The production of cured compost will be ca. 210 tons per year. 2.42 Vermicomposting Two-thirds of the fresh compost (ca. 900 tons/year) will be stabilized by means of vermiculture, which will take place in an insulated hall at 25 degrees Centigrade in a system of trays in 7 storeys. In the vermicomposting process, a tropical species from East Asia, Perionyx escavatus, will be used instead of the spe- cies Eisenia foetida (manure or dung worm), which is common in Denmark, and until now the species mostly used for vermi- culture. The two species are more or less equal according to the size, growth, and reproduction potential, but Peri- onyx excavatus doesn't - as in the case of Eisenia foetida - segregate any evil smelling secretion, which means that it can be utilized directly as a living fodder in fish produc- tion. (To be continued)