Biodiesel (methyl ester) produced from trans esterification of waste cooking oil is a potential material to replace diesel fuel. The biodiesel can be obtained by using electrostatic method equipped with fixed distance electrode 1.5 cm and voltage at 12 volts. Coagulation of particle process i.e. glycerin drops in biodieselglycerin mixture was based on electrical field. Reactants used were methanol over KOH catalyst and temperature was set at 60 C. The residence time was varied as well as methanol to waste cooking oil ratio. Analysis result shows the process was able to obtain yield up to 83.3%. The quality of biodiesel produced was tested and satisfy the requirement according to National Standard of Indonesia (SNI), i.e. density 0.8594 mg/mL (compared to SNI: 0.85-0.90 mg/mL), flash point 191 C (SNI min 100 C), water content 0.0342% (SNI max 0.05%) and viscosity at lower limit 2.31 cSt. According to SNI 7182-2015 the above value meets the specified standard.

Electrocoagulation is one of methods used to treat wastewater in the coal stockpile without using coagulants. Characteristics of wastewater observed are heavy metals (Fe and Mn) and pH. The decrease in the heavy metals content and the increase in the pH of this wastewater treatment process will then be proposed in the adsorption kinetics model. The influence of variations in currents and processing time were observed. The time variation of the adsorption process were 60 to 120 minutes with current variations from 1.3 to 3.0 Ampere at a fixed 12 voltages. The results obtained that the Fe content could be decreased to 0.03 ppm at 90 minutes while the content of Mn was decreased to 0.01 ppm at the same time. The increase in pH (7.11) was achieved when applying 2.5 A current at 90 minutes process time. The results obtained from the electrocoagulation method was then proposed in the model of the Langmuir isotherm adsorption kinetics and Freundlich isotherm.

Kerupuk and kemplang industries produce at least 65 liters of waste cooking oil per production. One of the applications of new and renewable energy can be done through the conversion of waste oilinto environmental friendly alternative fuel named biodiesel. The biodiesel production process can be conducted by various methods, such as utilizing induction heating technology. This technology has non-contact properties that do not interfere with the reactions that occur because of its application, which produces heat from the workpiece. This study uses waste cooking oil as raw material with variations in the molar ratios 1:3, 1:4, 1:5, 1:6, and 1:7. The analysis showed that the maximum biodiesel production was used of a 1:7 molar ratio with 86.95% yield, 0.86 gr/cm 3 of density, 5.73 cSt of viscosity, 190 o C of flash point, and 0.44 mg-KOH/gr of acid number. The using this ratio produces maximum yield and following SNI.

Eco-enzyme is a multifunctional liquid produced from fermentation of waste or organic waste, brown sugar or granulated sugar, and water. Fermentation of  eco-enzymes  is carried out for ±3 months. The length of time fermentation affects color, aroma and pH. The  resultingeco-enzyme liquid is dark brown and has a strong fresh sour aroma.  Eco-enzymeliquid has an alcohol content and acetic acid. Alcohol and acetic acid are produced from the bacterial metabolic process that is naturally present in the rest of fruits and vegetables. Variations in the fermentation time of eco-enzymes  used are 2.5 months and 3 months. Analysis conducted on  eco-enzymes  include pH tests and phytochemical screening  tests. The pH value obtained in  eco-eznyme  2.5 months is 3, while the pH value in  eco-eznyme  3 months is 1.5. Eco-enzymes  with a fermentation time of 3 months contain alkaloid compounds, flavonoids, saponins, and tannins. In this study  Eco-eznyme  was used as a hand sanitizer  spray by diluting the eco-enzyme with aquadest. The dilution ratios used vary for each sample: 1:40, 2:40, 3:40, 4:40, 5:40. Analysis conducted on  hand sanitizer spray include pH test, organoleptic test, and antibacterial activity test. Based on the results of the analysis, not all hand sanitizer samples meet SNI standards, the best samples obtained in hand sanitizer with an eco-enzyme fermentation time of 3 months and a dilution ratio of 5: 40. The results of the analysis showed that the value of pH 5, the level of aroma fondness in hand sanitizer 2.40, the favorite color level 2.46

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