A method of pumping an oilfield fluid from a well surface to a wellbore is provided that includes providing a clean stream; operating one or more clean pumps to pump the clean stream from the well surface to the wellbore; providing a dirty stream including a solid material disposed in a fluid carrier; and operating one or more dirty pumps to pump the dirty stream from the well surface to the wellbore, wherein the clean stream and the dirty stream together form said oilfield fluid.