Journal of Sustainable Technology and Applied Science (JSTAS)

PURIFICATION OF FISH POND WASTEWATER FOR REUSE

Lies Kurniawati Wulandari — 2025-11-19

This community service-based research is simply an effort to treat household wastewater to support the availability of clean water sources in urban areas. The type of waste treated here is graywater waste, which is wastewater that comes from kitchen and bathroom sinks or washing water (not feces and urine). The reason for choosing this type of graywater waste is because of its high production, which is up to 70-75% of the total liquid waste generated from domestic activities. The method used is a physical model in the laboratory using wastewater with a model scale that uses variations in discharge, number of vetiver stems, and residence time. The study's results indicated that the filter model improved wastewater quality, producing an output that met clean water standards. This demonstrates that using wastewater treatment filters with variations in water discharge, number of rods, and residence time effectively reduces pollutants in graywater.

OPTIMIZATION OF LIGHTING DESIGN IN OFFICE SPACES WITHIN THE FRAMEWORK OF ENERGY CONSERVATION

Ainun Zakiyah — 2025-12-16

Lighting conditions in office building B of UNISMA have not met the SNI standard because each room has the same number of lights for different rooms; this results in a large amount of electricity consumption from the lighting sector. The installation of the number of lamp armatures should be in accordance with the area of the room and then related to the function of the room and must also meet the standard lighting of the room (SNI 03 – 6575 – 2011.2011). For that, the calculation of the number of lamp armatures is appropriate for the standard and design of room lighting using Dialux software, where the office lighting standard is 350 Lux. Based on these steps, the lighting standard is produced approaching the SNI standard using Philips LED lights. With this design condition, the use of electrical energy becomes optimum and energy efficiency is achieved. Based on the Dialux software simulation, the percentage of savings in the initial conditions and design was 39%:61%.

CONVOLUTIONAL NEURAL NETWORK APPLICATION IN VOLCANIC TREMOR IDENTIFICATION DURING 2008-2009 PRE-ERUPTIVE EPISODE OF MT. SEMERU, INDONESIA

Ratri Andinisari — 2026-07-14

A convolutional neural network model has been constructed to classify volcanic tremor signals of Mt. Semeru during the year 2008 to 2009. This model was constructed by using unsupervised machine learning, precisely Convolutional Neural Network (CNN), and was trained without first providing any discriminating feature of the aforementioned volcanic tremor data. The dataset was first divided into training and testing datasets. The training dataset consists of 600 events recorded during 2008-2009 by seismic stations surrounding Mt. Semeru, including 300 volcanic tremors and 300 non-tremors. In order to increase the size of this dataset, data augmentation was carried out and producing a total of 4800 data with 2400 volcanic tremor and 2400 non-volcanic tremor events. The initial model was then trained by using 10, 15, and 20 epochs, resulting in the final model having training and validation accuracy rates of 99.51% and 96.93%, respectively. This model has successfully detected volcanic tremor signals in our testing dataset of 14 seismograms. This leads to the conclusion that unsupervised machine learning can be further utilized in volcanic activity monitoring system.

PELTON TURBINE WITH TWO NOZZLES: DESIGN AND PERFORMANCE ANALYSIS

Eko Yohanes Setyawan — 2026-07-14

This study utilized a laboratory-based Pelton turbine to investigate the impact of nozzle quantity on turbine power, torque, and efficiency. Analytical and empirical methods were employed to evaluate performance under 1- and 2-nozzle configurations, along with 21 turbine buckets. The findings revealed that increasing the number of nozzles led to higher rotational speed but reduced torque, which ultimately affected efficiency. The 1-nozzle configuration achieved a peak efficiency of 18%, while the 2-nozzle configuration produced more power but with lower efficiency. These results highlight the importance of optimizing nozzle count and water pressure regulation to enhance the performance of Pelton turbines in hydropower applications. This study provides valuable insights into nozzle design and configuration to maximize energy output from Pelton turbines and emphasizes the need to balance power, torque, and efficiency in turbine operation. Further optimization of these factors will support improved turbine effectiveness in harnessing the full potential of hydropower.