Coffee is an important export commodity for Indonesia. Coffee drying is post-harvest processing that greatly determines the coffee quality and microbiological safety. Conventional/sun drying is time-consuming, depending on the weather, and can potentially contaminate coffee beans by dust and moisture readsorption under high relative humidity. These problems could be avoided by employing artificial drying. This literature review aims to identify the current status of coffee drying technology, its advantages and limitations, to obtain coffee beans with the desired quality, duration of drying time, and energy consumption for processing. From the three types of thermal radiation dryers being reviewed, namely tray dryer, rotary dryer, and fluidized bed dryer, it was concluded that the drying air temperature and relative humidity must be selected properly to obtain the microbiological safety and the quality of the coffee brew. Efficient energy consumption requires a balance between the rate of water evaporation inside the coffee grain and the rate of water vapor removal from the solid surface by the air stream. The most efficient coffee drying is achieved at an air temperature of 50 o C, resulting in drying time and energy consumption of 65%, and 50% lower than that of 40 o C, with a good quality of the coffee brew. Fluidized bed drying combined with zeolite adsorption is potential to reduce the drying time due to an enhancement of air capacity to absorb water vapor. Application of microwave for coffee drying resulting in much shorter drying time than conventional thermal drying, but has a drawback of un-uniform grain temperature. A hybrid drying system could be implemented by using microwave and thermal oven.

Polypropylene is a widely used material for various types of equipment. As a recyclable thermoplastic polymer, polypropylene composite provides an attractive quality of thermal insulation due to its heat-retaining property. The use of rice straw for filler in thermal insulating material is based on its low thermal conductivity, renewable material, and low cost production techniques. The composite were manufactured by melt-mixing of neat polypropylene and filler of various weight fractions, pellet formation, followed by reprocessing with injection molding. The current work focused on determining the effect of filler’s weight fraction, particle size and pretreatment on the thermal conductivity and tensile strength of the composite. The result showed that an increase of filler’s weight fraction up to 30% decreased the composite’s thermal conductivity and tensile strength gradually. Composite of fine particles filler (325 mesh) gave a lower thermal conductivity and higher tensile strength than that of coarse particle (18-35 mesh). Composite with the lowest thermal conductivity of 1.39 W/mK was obtained at 30 w.% filler content and fine particles filler (325 mesh). Improvement on composite properties achieved by acetylated rice straw which enable to reduce straw’s hydophylicity and enhance adhesion between matrix and filler.

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Improving the competency of teachers at a vocational school (SMK) in Bandung carried out by lecturers in the Chemical Engineering Department of Politeknik Negeri Bandung is the main goal of this study. This also answers the hopes and proposal of the Principal of this SMK to continue cooperation in improving SMK teachers which was conducted in 2020 by lecturers in Politeknik Negeri Bandung (Polban). The activity to increase the competency of SMKN teachers in 2021 focuses on activities to increase the competency in wastewater treatment operation and matters related to the dangers of the operation. This topic has been chosen because currently the practical activities on wastewater treatment has not been carried out at this SMK. This competence improving activity could enrich the knowledge of SMK teachers related to wastewater treatment and then the knowledge could be transferred to the students and to the existing laboratory assistants at this SMK. All participants in this online training are in the competent category because they passed the post-test of the four modules and obtained a minimum score of 70 for each module. The Laboratory of Industrial Waste and Water Treatment in the Chemical Engineering Department Polban has complete industrial wastewater treatment equipment, making it possible to create a new Chemical Engineering Scheme for the Competency Test Place (TUK) possessed by this Department. Thus by conducting the training for the SMK teachers, it is not only beneficial for the teachers of SMK Bandung but also beneficial for the TUK of the Department of Chemical Engineering Polban by preparing the new Wastewater Treatment Scheme.

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Organic inhibitors in the corrosion process could be obtained from water hyacinth plant. This plant contained antioxidants such as saponins, which could bind to protective metals from corrosion. The objective of this study was to observe the corrosion rate degradation in rainwater and tap water with saponin content of water hyacinth extract with novelty of using methanol in the maceration process. The sample: methanol ratio used in the maceration process was 1 : 9 (w/v). Steel testing was carried out for 5 days in rainwater and tap water. Based on the test results, the saponin content in the water hyacinth extract could be proven by the stability of the foam produced. The experimental results showed a corrosion rate escalation in tap water samples from 47.7% to 94.5% and samples in rainwater from 11.3% to 52.9% at 75 ppm inhibitor concentration. Based on the research, water hyacinth extract using methanol solvent could be used as a corrosion inhibitor.

Green coffee beans to be stored for transportation must meet storage quality standards, especially the maximum moisture content of 12.5%, so the drying process must be carried out to achieve quality standards, but still economical. The study aims to obtain optimum operating conditions on the drying of Arabica-type coffee beans using a fluidized bed dryer assisted by zeolite adsorbents in a separated fluidized bed prior to heating, as well as calculating the energy consumption of blowers and air heater. The operating conditions were varied, namely air flow rate of 1.79 – 2.29 m/s, air temperature of 45 o C, 50 o C, and 55 o C, zeolite adsorbent mass of 150 g, 175 g, and 200 g.  The coffee beans quality tests carried out were the moisture, carbohydrates, protein content, and the visual appearance of the beans. The results show that the optimum drying process of coffee beans resulting a minimum protein and carbohydrate damage are the air velocity of 2.1 m/s, air temperature of 55°C, drying time of 240 minutes, and zeolite adsorbent mass of 150 grams, with energy consumption of 5.02 KWH (equivalent to 180 MJ/T). The addition of zeolite as much as 150 grams, 175 grams, and 200 grams as adsorbent was able to reduce the relative humidity (RH) of air by 16.65%, 18.60%, and 21.17% respectively.  The drying rate of coffee beans is mainly influenced by air temperature (more predominantly) than the adsorption of air humidity by zeolite.