Embodiments of the invention include a system for displaying an audit diagram. When a mobile station determines that there is demand for a new traffic connection, the mobile station may select a base station from which to request the desired traffic connection based on the QoS information and the loading information received from one or more base stations. In a flow passage through which treated water for the membrane module 3 flows, a water flow guide 5 is provided such that an opening area S2 of the flow passage through which treated water outflows is smaller than an opening area S1 of the flow passage through which treated water inflows. The via is filled with the insulator so that each of the metal layers is electrically isolated from each other.