The project consists of improving sewerage services to Piedras Negras, including the construction of a wastewater treatment plant (WWTP), with a capacity of 8.22 million galls per day (mgd). The new WWTP will replace an old oxidation lagoon system that was originally designed and built in the 1960’s to handle 2.63 mgd. The existing lagoon system is operating deficiently due to excessive clogging by sediments.