음식물류 폐기물 자원화시설의 관리체계 개선방안에 관한 연구

Abstract

A Study on the Improvement Plans of Management System for Food Waste Recycling Facility

Ryu Ji-Young Advised: Prof. Shin Dae-Yewn Ph. D. Department of Environmental Bioengneering. Graduate School of Chosun University

In this thesis, of all food wastes recycling facilities established in Korea, study was conducted on 72 public recycling facilities established and operated by the local government to look up the problems the facilities face at present and to identify improvement plans. The study proceeded with detailed analysis performed on the research data generated by an expert who visited the actual site. Detailed analysis was conducted by classifying the contents into collection and transportation system, establishment of recycling facility and general matters on operation, common facility on waste-water treatment, pre-treatment, deodorization, facility status of each treatment and recycling method(composting, feeding, anaerobic digester, etc.). In regards to collection and transportation of food waste, adequate standard on expense calculation should be set up and gradually imposed, and the collection and transportation vehicle should be replaced with exclusive vehicle without leachate leakage and odor spread, and etc. As for establishment and operation of recycling facility, with the food wastes recycling facility concentrated on composting and feeding in the order of "composting>feeding>anaerobic digester>combined treatment of waste-water>combined compost and feed," establishment of diverse treatment facility is required. In regards to establishment of recycling facility, it should be established in region where factory registration is possible, and should be based on assessment of standard establishment cost. Moreover, recycling facility should be established in the same lot as other fundamental facilities (sewage disposal plant, incinerator, landfill) in order to secure efficiency, in control of leachate and odor, energy saver, etc., from management point of view. In majority of the recycling facilities, pre-treatment, waste-water treatment, and odor treatment should be established as common facilities. In pre-treatment facility, sealing (vinyl bag crusher), crushing, and sorting facility is mandatory. It should be thoroughly separated from the sorting facility, and should adequately be handled with methods such as landfill, incineration, etc. as occurrences of foreign materials minimize. Waste water should be sorted into high concentration and low concentration, and treated within the facility to be discharged or initially treated within the facility and then finally treated at the sewage disposal plant. odor should be collected within the facility and be treated until the density reaches below the level specified in deodorization law prior to discharging it outside the facility. In composting facility, mix and dry of sawdust, conveyance of compost should be proceeded in order to adjust moisture in the initial stage, and the retention time should be maintained at over 15 days for 1st fermentation reactor, over 21 days for 2nd maturation reactor so that organic matters may sufficiently be decomposed. Moreover, quality (color, odor, stability level) should be controlled from those that have problems in distribution due to incomplete degradation of compost that are in the final stage of manufacture. Feeding facility may exert fatal influence to the animals should foreign materials(glass, metal, vinyl, etc.) be included in manufactured feed, and thus supplementation and improvement in the sorting facility should be realized. Moreover, as Feed Control Law stipulates that matters be sterilized by processing over 30 minutes under heating temperature of 80℃ or 100℃ at the feeding facility, these conditions must be complied. The anaerobic digester of food wastes should comply with the retention time (over 15 days), and should be used for the purpose of burning gas to warm the digester facility. Remaining gas should generate electricity and produce electricity. Moreover, waste-water treatment facility should be established to treat high concentration waste-water generated from digestive liquid, or be treated in connection with sewage treatment plant of nearby area. The management system and recycling facility of food wastes have undergone many trials and errors since article on prohibition of direct landfill was set up in Waste management Law in 1997, which led to the improvement of the management system and facility, and in turn to proceed to technology development. It has created recycling system of food wastes, first of its kind globally, and it is expected to develop to a higher level of standard. The items pointed out in this study is expected to greatly contribute in the management system and recycling facility of the food wastes.