In this study, new sustainable resource recycling networks that could produce an effective resource from an industrial waste resource were investigated. In order to achieve this objective, the biological, physical and chemical reactions were applied and various technologies based on environmental engineering were also utilized. As a result, three recycled resource were successfully developed as follows.
1) Development of stable and economical alternative external carbon source by using organic by-product of high concentration produced in 1,4-butanediol(BDO) manufacturing process, 2) Development of carbon source, 1,4-BDO and Tar by applying distillation technology using B/D tar generated in 1,4-BDO manufacturing process, 3) Development of Al2(SO4)3 solution by using chemical polymerization and substitution reaction from a spent catalyst including aluminium(waste activated alumina) generated in the manufacturing process of the polymer. From these three recycled resource, the derived conclusions were as follows.

1. Manufacturing and estimation of carbon source using by-product of 1,4-butanediol production process
In this study, the mixed liquor of organic wastes (MLOW) produced from a 1,4-butanediol production process was tested as an external carbon source for denitrification in a biological nutrient removal (BNR) process. The fraction of non-biodegradable chemical oxygen demand (NBDCOD) in the MLOW was estimated to be approximately 0.2% by measuring the oxygen uptake rate (OUR). The specific denitrification rate (SDNR) of MLOW and methanol from a nitrate utilization rate (NUR) test was confirmed to be approximately 13.02 and 12.68 mgN/gVSS/hr, respectively. This result indicated that the denitrification capability of microorganisms applying the MLOW was similar to that of using methanol as an external carbon source for the BNR process. The feasibility of MLOW for a stainless steel wastewater treatment plant (WWTP) was investigated. The low concentration of effluent nitrogen indicated a denitrification capability for MLOW similar to that for methanol. These results support the potential of MLOW as a substitute for methanol in the BNR process. Also these results supported the conclusion that the MLOW produced from the 1,4-butanediol process could be effectively used as an external carbon source capable of replacing methanol. Such replacement is expected to offer a chemical cost savings of more than 22% for the SS WWTP and of more than 1 million dollars for the company producing the MLOW.

2. The development of technology for the recovery of useful resources from by-product of 1,4-butanediol manufacturing process
In this study, the experiment to find the optimal condition for the recovery of 1,4-butanediol with the purity above 85% from Blow down tar(B/D tar) was performed by using resource recycling pilot plant. As result of it, the operation condition distilled for 170 min at 210℃ under 10 torr vacuum pressure was determined as an optimal condition, which shown 25% recovery rate with the 1,4-butanediol purity above 85%. In case of first by-product(that is low alcohol liquid) of pilot plant, the usefulness as an alternative external carbon source at the biological nutrient removal wastewater treatment plant(BNR WWTP) was evaluated through the analysis of COD, T-N, T-P and heavy metal concentration, and OUR(oxygen uptake rate) test, and NUR(Nitrate utilization rate). It was estimate that COD concentration of the first by-product was estimated very high by 82,000 mg/L. And it was expected that there would be no the increase of T-N and T-P concentration at the effluent because of low concentration of T-N and T-P when the first by-product was used as an alternative external carbon source. It was confirmed that the metal concentration was not too high enough to occur the toxicity of microorganism. It was evaluated that the non-biodegradable fraction was 0.4% by OUR test. It was expected that there would be no increase of effluent COD concentration by using as an alternative external carbon source. The SDNR(Specific Denitrification Rate) was estimated as 10.86 mgN/gVSS/hr by NUR test, which was similar to methanol''s SDNR (11.10mgN/gVSS/hr). Therefore, it was possible for us to conclude that the first by-product could be an useful alternative external carbon source at BNR WWTP. In case of tar that was final by-product, the usefulness as an auxiliary substance for the manufacturing of refuse plastic fuel(RPF) was estimated by the investigation of caloric value, water content, chloride content and unhealthy metal content. It was confirmed that the caloric value, the content of water and chloride was satisfied with the RPF standard. The caloric value was 7,170kcal/kg and the content of water and chloride was 1%, 488mg/kg. And there was no unhealthy metal in the final by-product. Therefor, it was possible to conclude that the final product, that is, Tar could be used as an auxiliary substance for the manufacturing of RPF. In this study, the economical benefit was estimated when the establishment of B/D tar recycling network. It was estimated that the price of waste disposal would be saved by 350,000 thousand won/year and 520,000 thousand won''s sales would be produced by selling the 1,4-butanediol and low alcohol water. It was expected that BNR WWTP would save 7,000 thousand won/year by substituting methanol by using alternative external carbon source.

3. Production of alternative coagulant using waste activated alumina and evaluation of coagulation activity
In this study, the production potential of alternative coagulant(Al2(SO4)3 solution) having the identical coagulation activity with respect to the commercial coagulant was investigated. The raw material of alternative coagulant was a spent catalyst including aluminium(waste activated alumina) generated in the manufacturing process of the polymer. The alternative coagulant was produced through a series of processes: 1) intense heat and grinding, 2) chemical polymerization and substitution with H2SO4 solution, 3) dissolution and dilution and 4) settling and separation. To determine the optimal operating conditions in the lab-scale autoclave and dissolver, the content of Al2O3 in alternative coagulant was analyzed according to changes of the purity of sulfuric acid, reaction temperature, injection ratio of sulfuric acid and water in the dissolver. The results showed that the alternative coagulant having the Al2O3 content of 7∼8% was produced under the optimal conditions such as H2SO4 purity of 50%, reaction temperature of 120℃, injection ratio of H2SO4 of 5 times and injection ratio of water of 2.3 times in dissolver. In order to evaluate the coagulation activity of the alternative coagulant, the Jar-test was conducted to the effluent in aerobic reactor. As a result, in both cases of Al/P mole of 1.5 and 2.0, the coagulation activity of the alternative coagulant was higher than that of the existing commercial coagulant. When the production costs were compared between the alternative and commercial coagulant through economic analysis, the production cost reduction of about 50% was available in the case of the alternative coagulant. In addition, it was identified that the alternative coagulant could be applied at field wastewater treatment plant without environmental problem through ecological toxicity testing.