The intensive development of the petrochemical industry globally reflects the necessity of an efficient approach for oily sludge and wastewater. Hence, for the first time, the current study utilized magnetic waxy diesel sludge (MWOPS) to synthesize activated carbon coated with TiO2 particles for the removal of total petroleum hydrocarbons (TPH) and COD from oily petroleum wastewater (OPW). The photocatalyst was characterized using CHNOS, elemental analysis was performed using X-ray fluorescence spectroscopy (XRF), field emission scanning electron microscope (FESEM), high-resolution transmission electron microscope (HR-TEM), X-ray diffraction analysis (XRD), Fourier transform infrared spectrometer (FTIR), Raman, energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), MAP thermo-gravimetric analysis/ differential thermo-gravimetric (TGA–DTG), Brunauer–Emmett–Teller (BET), diffuse reflectance spectroscopy (DRS), and vibrating sample magnetometer (VSM). The optimization of synthesized highly porous AC/Fe3O4/TiO2 photocatalyst was conducted considering the impacts of pH, temperature, photocatalyst dosage, and UVA6W exposure time. The results demonstrated the high capacity of the MWOPS with inherent magnetic potential and desired carbon content for the removal of 91% and 93% of TPH and COD, respectively. The optimum conditions for the OPW treatment were obtained at pH 6.5, photocatalyst dosage of 250 mg, temperature of 35 °C, and UVA6W exposure time of 67.5 min. Moreover, the isotherm/kinetic modeling illustrated simultaneous physisorption and chemisorption on heterogeneous and multilayer surfaces. Notably, the adsorption efficiency of the AC/Fe3O4/TiO2 decreased by 4% after five adsorption/desorption cycles. Accordingly, the application of a well-designed pioneering photocatalyst from the MWOPS provides a cost-effective approach for industry manufacturers for oily wastewater treatment.

This paper develops an algorithm to determine the batch size of the batch process in real time for improving production and efficient control of production system with multiple processes and batch processes. It is so important to find the batch size of the batch process, because the variability arising from the batch process in the production system affects the capacity of the production. Specifically, batch size could change system efficiency such as throughput, WIP (Work In Process) in production system, batch formation time and so on. In order to improve the system variability and productivity, real time batch size determined by considering the preparation time and batch formation time according to the number of operation of the batch process. The purpose of the study is to control the WIP by applying CONWIP production system method in the production line and implements an algorithm for a real time batch size decision in a batch process that requires long work preparation time and affects system efficiency. In order to verify the efficiency of the developed algorithm that determine the batch size in a real time, an existed production system with fixed the batch size will be implemented first and determines that batch size in real time considering WIP in queue and average lead time in the current system. To comparing the efficiency of a system with a fixed batch size and a system that determines a batch size in real time, the results are analyzed using three evaluation indexes of lead time, throughput, and average WIP of the queue.

A사는 발전 플랜트, 오수처리장, 취수, 정수, 배수장, Oil Plant 등 국가 기간 산업현장에서 사용되는 전동 액추에이터를 제조하고 있다. A사가 각 수요처별로 각기 다른 기능을 필요로 하는 Order에 대응하여 제품을 생산하고자 기존의 A사가 적용하고 있는 생산방식인 라인로트생산방식이 가지고 있는 문제점을 파악하여 개선하고자 한다. 본 연구를 통해 시장과 고객의 요구에 유연하게 대응할 수 있도록 다품종 소량생산에 적합한 셀 생산방식으로 변경을 통하여 생산유연화와 생산성향상을 이룰 수 있었다. 이러한 개선을 통하여 다변화하는 고객의 요구에 실시간으로 대응 할 수 있음은 물론이고 생산성향상과 그에 따른 이익창출을 이뤄낼 수 있는 계기가 될 것이다. 또한 A사의 생산 작업자의 업무 능력배양에 긍정적으로 작용하여 일을 하는 재미와 이에 따른 보상의 기대치를 높일 수 있는 계기로 작용하였다.

It is not easy to establish the correct standard time and standard manhour in a process of small quantity batch production system, especially in a case of irregular quantity of production. Therefore, how to establish rational standard time about manufactu

Anaerobic mesophilic batch tests of food waste and food waste leachate collected from food waste treatment facility were carried out to evaluate their ultimate biodegradability and two distinctive decay rate coefficients (k1 and k2) with their corresponding degradable substrate fractions (S1 and S2), respectively. Each 3 liter batch reactor was operated for more than 60 days at substrate to inoculum ratio (S/I) of 0.5 as an initial total volatile solids (TVS) mass basis. Result of Ultimate biodegradability of 74 ~ 83% for food waste and 85 ~ 90% for food waste leachate were obtained respectively. The readily biodegradable fraction of 85 ~ 93% (S1) of food waste Biodegradable Volatile Solids (BVS, So) degraded within the initial 15 days with a range of of 0.151 ~ 0.168 day−1, whereas the rest slowly biodegradable fraction (S2) of BVS degraded for more than 53 days with the long term batch decay rate coefficients of 0.009 ~ 0.010 day−1. For the food waste leachate, the readily biodegradable portion (S1) appeared to be 92 ~ 94% of BVS (So), which degrades with of 0.172 ~ 0.206 day−1 for an initial 15 days. Its corresponding long term batch decay rate coefficients were 0.005 ~ 0.009 day−1. It is recommended that the hydraulic retention times of mesophilic anaerobic digesters be 16 days for the food waste and 15 days for the food waste leachate, respectively. However a safety factor should be considered when designing a full scale plant.