MISEIC 2018 Surabaya, July 21, 2018 Conducting a Real-Time Instrument System for Observing Biogas Digester’s Temperature and Humidity Meta Yantidewi*1, Nurita Apridiana Lestari 2, and Utama Alan Deta 2 1, 2 Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Surabaya, INDONESIA. (E-mail: metayantidewi@unesa.ac.id, nuritalestari@unesa.ac.id, utamadeta@unesa.ac.id) ABSTRACT Anaerobic digestion is a biochemical process that converts various organic materials into biogas using oxygen-free microorganisms naturally (Botheju & Bakke, 2011). In addition to producing biogas, anaerobic digestion process also produces a liquid effluent (called digestate) containing all water, all minerals, and about half of the carbon deriving from the incoming material. Anaerobic digestion process in biogas production generally takes place in the digestive tank or better known as biogas digester. However, some parameters might affect the process. Gu et al, as cited in Panjaitan et al (2016), stated that temperature and humidity play important role in the anaerobic digestion process of biogas. This research aims to present an instrument system for observing the temperature and humidity percentage in a biogas digester. The instrument system will observe the temperature and humidity inside the biogas digester in real-time to ensure that no interference occurs in the biogas digester during the anaerobic digestion process. A real-time instrument system is defined as a system that responds toward transactions by immediately updating and/or generating a response in a time frame fast enough to keep an operation moving at its required speed. The instrument system, as described in Figure 1, was mainly constructed of the biogas digester acquisition system and its observing by the user through the application. 1 . BIOGAS DIGESTER Temperature and humidity inside the biogás digester Data Acquisition Devices COMPUTER Figure 1. The block diagram of the real-time instrument system. The temperature and humidity inside the biogas digester were detected by a single chip multi-sensor SHT11. The sensor information was then acquired by the data acquisition devices. All processing of temperature and humidity data inside the biogas digester became the data acquisition devices’ responsibility. The data acquisition devices subsequently passed the processed data to the computer. The computer acted as information viewer system regarding the temperature and humidity inside the biogas digester. The information viewer system showed the information of temperature and humidity in the biogas digester during anaerobic digestion process. The viewer system used Delphi as its application. The information of temperature and humidity in biogas digester which gathered by SHT11 in this research are shown in Figure 2. Figure 2. The viewer system displays the information of temperature and humidity in biogas digester. The temperature and humidity information were displayed in the forms of line graphs and table. Because the built system is a real-time system, it follows that the system is also capable of displaying temperature and humidity percentage in accordance with the search date. In general, we can say that the instrument system built in this research has ability to observe and measure the temperature and humidity in biogas digester. Thus, the real-time instrument system can be utilized as a viable and easy alternative for the monitoring/observation of anaerobic digestion in biogas production. Keywords: Anaerobic digestion, biogas digester, real-time instrument system, observing, temperature, humidity. 2