DETAILED DESIGN OF RAINWATER HARVESTING SYSTEM IN ITB GANESHA CAMPUS, BANDUNG

• Main Author: Prastiti, Setyaning
• Format: Final Project
• Language: Indonesia
• Subjects: Teknik saniter dan perkotaan; teknik perlindungan lingkungan
• Online Access: https://digilib.itb.ac.id/gdl/view/34473
• Institution: Institut Teknologi Bandung

Institut Teknologi Bandung Ganesha Campus is a land that mostly consists of institutional and office building. Since those buildings are not residential, most of treated water in ITB are allocated to fulfill latrine necessities. In order to fulfill such necessities, ITB uses water supplied by Water Utilities (PDAM). Using PDAM-produced water sure comes with some cost. And so, by treating rainwater that pours onto the rooftop of each building, the amount of water that the particular building ought to buy from PDAM can be reduced. On the other side, in order to distribute PDAM-produced water throughout each building in ITB, pump is needed to raise water from ground tank to roof tank. By putting the roof tank in certain elevation, enough head to distribute water to the entire building can be accomplished. Hence, on buildings that allow the treatment unit to be put at some elevation within the building, the original head that comes with the rain can be used, and so the demand of pump work can be reduced, in a system called Rooftop Rainwater Harvesting (RRH). The rain that falls onto buildings without RRH, and those that falls straight onto the ground surface, added with the overflow of RRH treatment units, can later be treated together in a central system called Ground Rainwater Harvesting (GRH). To achieve that goal, the initial step that needs to be done is to find out the quality of rainwater that is about to be catched. This data will be used to determine whether the rainwater needs to be treated first, along with choosing the right treatment for such qualifications. For rainwater harvesting in ITB Ganesha, the right treatment is rapid sand filtration, using 30 cm thick of silica sand, 40 cm of anthracite, and 30 cm of granular activated carbon. Before treating, the already catched rain needs to be stored, using 2-4 horizontal tanks of 2000 L or 4200 L for the RRH system, while the GRH system uses 12 underground concrete wells, each 6,5 m x 6,5 m x 5 m in size. These treatment units are next to be designed, in which the design needs to be as simple as possible, so that the units are not only built out of equipments that are easy to attained, the operation procedure needs to be simple and not labor intensive, also can be placed without having to built expensive additional construction that recquires large space in order to support the units. After unit designs with such criteria is obtained, the next to be designed is catchment devices, conveyance to channel the water into the treatment units.