Aerobic Wastewater Treatment System - Installation McKittrick Precast Concrete (MPC) is the factory authorized representative for Solar Air Wastewater Treatment Systems in North Eastern Oklahoma. Our network of factory certified distributors can help you determine the system you need, and then install and maintain the system for you. MPC installers are chosen for their high ethical standards and willingness to provide high quality installations and service. Go to the contact page to contact an MPC representative who can assist you in finding a certified installer in your area. Gallery