Hydromantis GPS-X GPS-X is a wastewater treatment plant simulator program developed and published by Hydromantis Inc. GPS-X is a modular, multi-purpose computer program for the modeling and simulation of municipal and industrial wastewater treatment plants. Whether you are designing a new facility, or simulating an existing plant, GPS-X will help you improve your design and operating efficiency. GPS-X Version 6.0 is the State-of-the-Art in wastewater process simulation. Featuring the industry's easiest-to-use interface and most comprehensive suite of wastewater models, GPS-X provides engineers with a proven tool for process analysis.