Assessment of Physical Parameters of Indoor Air Quality in A Wastewater Treatment Plant Building: A Case Study

Abstract

Safe building conditions, clean air, and a positive workplace environment have a significant impact on employees’ well-being and productivity. A safe building condition includes a good and efficient air conditioning system in a building to provide quality indoor air for employees. This study aims to measure physical parameters, including air temperature, relative humidity, and carbon dioxide, in wastewater treatment plants and to identify potential issues contributing to poor air quality. A total of 33 stations were selected in three buildings. The inclusion criteria of the chosen locations were a centralized air conditioning system, a split air conditioning system, and places with natural ventilation. The measurements were conducted following the Industrial Code of Practice for Internal Air Quality Industry (ICOP) 2010 and the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 2005. Carbon dioxide levels in three locations were below 1,000 ppm and were compliant with ICOP-Department of Occupational Safety and Health (ICOP-DOSH) and ASHRAE standards. Office rooms recorded the highest carbon dioxide level at 914 ppm. Factors contributing to the level of carbon dioxide are the activity of body metabolites, breathing, and conversations. The lobby area, office rooms, cafeteria, pantry, surau, toilets, pre-treatment facilities, clarifier process facilities, and sludge digestion recorded high relative humidity (>70%), which exceeded the standards. The cafeteria is the only station with a high temperature (26.6°C), exceeding the standard. Internal ventilation systems should be regularly maintained to ensure that air is free from contamination by foreign materials, pathogenic germs, and in compliance with air quality standards.