More than 10 major water-treatment plant makers, including Mitsui Engineering & Shipbuilding Co. and Mitsubishi Heavy Industries Ltd., were searched Tuesday by the Fair Trade Commission on suspicion of repeatedly rigging bids for contracts from local governments, as reported by the Japan Times. Also raided were Sumitomo Heavy Industries Ltd., JFE Engineering Corp., Kubota Corp., Ebara Corp., Hitachi Zosen Corp., Takuma Co. and Ataka Construction and Engineering Co. Most of the companies confirmed they were being searched by the antimonopoly watchdog but declined comment on the reason. The firms are suspected of conspiring to select bid winners and fix bid prices for contracts for building water-treatment plants…