Rio Grande do Sul state water utility Companhia Riograndense de Saneamento (Corsan) supplies 97% of residents in its coverage area with potable water supply and 11.6% with sewerage services. The company's 2015-20 plan calls for some US$744mn in total investment. It is planning on calling US$84.2mn in tenders in 2015 for wastewater works in 18 municipalities. One sewage treatment plant will be built in each of the municipalities of Canela, Capão da Canoa, Portão, and Tramandaí. A tender to expand the existing Mato Grande sewage treatment plant in the city of Canoas is also planned. Sewer systems will also be built in the cities of Parobé, Sapiranga and Taqua. Other work such as laying interceptor and collector pipelines, installing building connections and building pumping stations, force mains and outfalls are planned in the municipalities of Alegrete, Alvorada, Cachoeirinha, Carazinho, Esteio/Sapucaia do Sul, Passo Fundo, Santa Rosa and Venâncio Aires. A tender for a wastewater concession in the city of Erechem is also planned to be launched this year. The 24-year public-private partnership involves installing a wastewater treatment plant, collector and interceptor pipelines, building hookups and sludge disposal facilities. Its subsidiary Companhia de Indústrias Eletroquímicas (Ciel) produces aluminum sulfate, a common coagulant used in water-treatment facilities.