Sewage treatment facilities are one of the social infrastructures that support our daily lives. Here, the circulation of water is maintained by the proper treatment of water. In order to ensure proper treatment, it is important to accurately grasp the water quality. In order to respond to stable measurements even in harsh environments, HORIBA has been developing meters for sewage treatment since early on, and has contributed to the circulation of water by offering a wide range of measuring items, sensors, and proprietary washing instruments. We also believe it is important to contribute to the reduction of environmental impact by developing control sensors that can contribute to energy-saving control.