Study of Contact Time and Media Thickness on Rainwater Harvesting Technology Filtration at Tidar University

E-ISSN: 2528-388X P-ISSN: 0213-762X INERSIA Vol. 19, No. 1, May 2023 Study of Contact Time and Media Thickness on Rainwater Harvesting Technology Filtration at Tidar University Agredetya Nada Fairuz*, Achmad Rafi’ud Darajat, Muhammad Amin Civil Engineering Department, Faculty of Engineering, Tidar University, Jl. Kapten S. Parman No. 39 Magelang 56116, Indonesia ABSTRACT Keywords: Filtration, Rainwater Harvesting, Logistic Regression, Thickness of Media, Contact Time Rainwater harvesting as an alternative raw water source can reduce water runoff. However, rainwater has been in contact with various pollutants in the air. In testing in Building 3, Faculty of Engineering, Tidar University, rainwater contained levels of E. Coli 8 CFU/100ml and Coliform 69 CFU/100ml which exceeded the quality standard of the Minister of Health Regulation No. 32 of 2017. This study aims to see the effect of media thickness and contact time on each mediA to improve rainwater quality using the Vertical Flow Roughing method. Up Flow filter flow with 3 filters containing zeolite gravel, activated carbon, and volcanic sand, with each having 3 different thickness variations, namely 60 cm, 70 cm, and 80 cm. The filter is operated for 18 minutes with sampling every 6 minutes. The results of logistic regression and log likelihood test showed that there was no significant effect on all filtration media in reducing the value of E. Coli and Coliform, but the highest efficiency occurred at 18 minutes with a thickness of 80 cm in each medium. In zeolite gravel filtration, the efficiency of reducing E. Coli and Coliform reaches 100%. In activated carbon filtration, the efficiency of E. Coli reduction was 100% and Coliform 51%. In volcanic sand filtration, the efficiency of E. Coli reduction is 100% and Coliform is 35%. ` This is an open access article under the CC–BY license. does not form spores, and is a natural flora in the mammalian intestine [2]. E.coli is also known as hygiene and hygiene indicator bacteria, namely the presence of bacteria in food which indicates a low level of sanitation hygiene applied. 1. Introduction Rainwater Harvesting (RWH) is a rainwater harvesting method that utilizes the roof of a building as a rainwater storage medium. Rainwater that falls on the roof of the building is channeled through pipes to then be collected and stored in a reservoir [1]. In the rainwater test in Building 3, Faculty of Engineering, Tidar University, the rainwater contained levels of E. Coli 8 CFU/100ml and Coliform 69 CFU/100ml which exceeded the quality standard of Minister of Health Regulation No. 32 of 2017. The research aims to see the effect of media thickness and time. contact on each medium to improve the quality of rainwater. Based on the literature study, one of the water treatments that can be done to overcome these problems is the filtration process. Water that moves vertically or perpendicularly makes solid pollutants contained in the water able to settle at the bottom of the filtration. In the Up Flow vertical filter, it is supplied by water flowing at the bottom of the filter [3]. Filtering using an upflow system is believed to be more effective in reducing the occurrence of deadlocks on the media. In addition, it is easier to clean the media. The upstream filtration system does not require chemicals, can remove manganese, iron, as well as color and turbidity. The Up Flow filtration system can also remove organic pollutants and ammonia [4]. Coliforms are a group of bacteria that are used as indicators of microbial contamination of water quality, usually through feces whose conditions impair the quality of water, food and beverages. The Coliform group as a group of bacteria is characterized by rod-shaped, gramnegative, non-sporing, aerobic, and facultative anaerobic bacteria that ferment lactose to produce acid. Escherichia coli is one of the Coliform bacteria belonging to the Enterobacteriaceae family. Escherichia coli is a gramnegative, facultative anaerobic rod-shaped bacterium, The thickness of the media and the time of filtration affect the water quality, it can be concluded that the thickness of the filter media has a large effect on the filtration discharge and reduces the value of the parameters 133 Agredetya Nada Fairuz, et al. INERSIA, Vol. 19, No. 1, May 2023 contained in the water, the thicker the filter media, the smaller the value of the parameters contained in the water. slows down the filtration discharge, but the quality of the water produced is better [5]. particles from the water because the grains of sand have pores that are small enough, so that larger particles can be retained. 2. Methods Schematic of the research method for the study of contact time and media thickness on rainwater harvesting technology filtration at Tidar University is shown in Figure 1. Figure 2. Zeolite gravel filtration variations Figure 3. Vulcanic sand filtration variations Figure 1. Research method scheme In this study, media with a thickness of 80 cm, 70 cm, and 60 cm were used in each variation per medium and the contact time for each filter was 6 minutes, 12 minutes, and 18 minutes. 2.1. Tools and Materials The filtration device is made using a 4” PVC pipe with a length of 1,2 meters. Then the materials needed are zeolite gravel, activated carbon, volcanic sand, and filter cotton. Details of the arrangement of the media layers in each filter are shown in Figure 2, Figure 3, dan Figure 4. Sand has advantages as a filter medium because the particles are free, porous, degraded and homogeneous. Volcanic sand has the ability to filter dirt and small Figure 4. Activated carbon filtration variations 134 INERSIA, Vol. 19, No. 1, May 2023 Agredetya Nada Fairuz, et al. Volcanic sand has the same properties as silica sand > 60% which is able to reduce turbidity, manganese and iron. In addition, volcanic sand is easy to obtain and the price is relatively cheap [6]. where Q is the flow rate, V is the volume of the water holding container per unit liter, and t is the time it takes the water to fill the container per unit second. (2) Filter Efficiency The results of the filtration are analyzed in the laboratory to determine the efficiency of the decrease that occurs in the E. Coli and Coliform parameters, after the results are known, the efficiency can be sought by comparing the influent and effluent and expressed in percent. Efficiency calculation: Activated carbon or Granular Activated Carbon (GAC) is free carbon and has an inner surface, so it has good adsorption properties. Activated carbon is able to remove organic content from water and also reduces unpleasant odors, colors and tastes. Activated carbon has a very strong adsorption capacity due to its high adsorption pore volume. A study showed that activated carbon filtration systems using granular activated carbon were more effective at removing chlorine, bad odors, and microorganisms. The activated carbon filter desi (...truncated)