Senzo Water Purification Plant

Osaka’s thirst for pure water. This is the story of the Senzo Water Purification Plant. It’s a tale of a city’s struggle for clean, safe drinking water. In the late 1960s, Lake Biwa, the “water reservoir of the Kinki region”, faced a crisis. An explosion of phytoplankton growth, fueled by eutrophication, threatened the water supply. This problem peaked in the 1980s. Metabolites from these phytoplankton tainted Osaka’s tap water with a musty odor. The Yodo River, Osaka’s primary water source flowing from Lake Biwa, also suffered. Population growth and industrial development further degraded its quality. Adding to the woes, trihalomethane, a byproduct of the water treatment process, raised cancer concerns. The Senzo Water Purification Plant, like others using the Yodo River, relied on the rapid filtration system. Effective for removing turbidity, this system struggled with the musty odor and trihalomethane. Even trace amounts of pesticides and other organic matter became a worry. Though trihalomethane levels remained below standards, Osaka needed a better solution for the Senzo Water Purification Plant and its citizens. The Osaka Municipal Waterworks Bureau partnered with Kubota. Together they implemented a pilot program at the Senzo Water Purification Plant, a highly advanced purification system. This new system integrated ozone and granular activated carbon treatment into the existing process. Ozone, a powerful oxidizer, attacked the organic compounds causing the musty odor while also disinfecting the water. Granular activated carbon trapped other organic substances and trihalomethane precursors in its tiny pores. Microorganisms living on the carbon’s surface then broke down these trapped contaminants. The results at the Senzo Water Purification Plant were impressive. The musty odor vanished. Trihalomethane levels dropped by 60-70% compared to the old system. Osaka finally had tap water that was both safe and delicious, a testament to the Senzo Water Purification Plant’s innovation. But the journey for pure water never truly ends. The Senzo Water Purification Plant continues to adapt. It stands as a symbol of Osaka’s commitment to its citizens’ well-being.