DESIGN OF UPRATING LAE MBULAN WATER TREATMENT PLANT PDAM TIRTA NCIHO SIDIKALANG

• Main Author: Kaleb B. Sitorus, Josua
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/70749
• Institution: Institut Teknologi Bandung

Water is the most component needed by every creature on earth, including humans. Water isn’t used just for drinking water, but water is needed for cooking, washing, etc. Along with increasing the population and economics, drinking water needs are increasing. However, raw water quantity in nature is limited and the quality always changes according to the season. Because of it, is important to have a water treatment plant that could produce drinking water that has met the standard quality in every season. Dairi Regency is placed in North Sumatra. Dairi Regency has a total area of 1927,8 km2 with an elevation of 400 – 1700 meters from the sea level. The total population in Dairi Regency in 2020 is 308.764, of which the male is 154.628 and the females 154.136. Dairi Regency has a sex ratio is 100,32% and a population density is 160,16 people/km2. Most of the people in Dairi Regency work in agriculture, services, and manufacturing. Based on Susenas 2020, the feasible drinking water access is 78,27%. PDAM Tirta Nciho is a municipally owned corporation that works in drinking water service. PDAM Tirta Nciho has 10 distribution areas that service Dairi Regency with a distribution time is 23,16 hours. A branched system with gravitational distribution is the distribution system used by PDAM Tirta Nciho. Lae Mbulan water treatment plant is one of the water treatments in Dairi Regency that serves drinking water need in Sidikalang. Based on the analysis, the maximum capacity of Lae Mbulan water treatment is 43,29 L/s with domestic water needs 76,92 L/p/d. A slow sand filter system with aeration, sedimentation, filtration, and disinfection configuration is the treatment system used in Lae Mbulan WTP. The coliform and E. coli parameter is not meet the quality standard in the produced water because the re-sanding process was never done and lack of a period disinfection process. Linear regression is the population projection method used in Sidikalang, Berampu, Siempat Nempu, and Siempat Nempu District. Based on population projection, the Drinking Water System Master Plan of Dairi Regency, Technical Recommendation of Water Resources Management Permission, Directorate General of Human Settlements Criteria, and the observational data, the water needs in 2042 96,65 L/s. In the Drinking Water System Master Plan of Dairi Regency, the new water treatment plant would have built has a capacity of 100 L/s. Based on this result, the new water treatment plant could have met the drinking water need 20 years later. National Standard Code and JICA are used to make four treatment alternatives. Based on decision-making using an analytic hierarchy process, the best alternative is the fourth alternative. To determine the dimension of each unit, the criteria design and assumption are used in the planning process. Based on the calculation, the aerator needed is 1 unit, the filtration unit neededis 3 units, the disinfection unit needed is 1 unit, the reservoir needed is 1 unit, and the sludge drying bed unit needed is 3 units. The minimum area used in the new water treatment plant is 2313 m2. The capital expenditure for the new WTP build is Rp 6.236.541.000 with the operational expenditure being Rp 647.720.460 each year. Economic analysis using IRR proves that the design of uprating WTP is feasible.