Water treatment process for oilfield produced water

A waste water treatment system comprising:

• a waste water feed stream;
• a warm lime softening system in fluid communication with the waste water feed stream, wherein the warm lime softening system comprises a lime silo, a sodium carbonate silo and a caustic storage tank in fluid communication with a lime and soda precipitation softener vessel;
• a sludge storage tank in fluid communication with the lime and soda precipitation softener vessel, wherein contacting the waste water feed stream with lime and sodium carbonate in the lime and soda precipitation softener vessel produces a particulate suspension that settles to produce a sludge that is recycled back to the lime and soda precipitation softener vessel;
• a microfiltration system in fluid communication with the lime and soda precipitation softener vessel;
• a first pass reverse osmosis system in fluid communication with the microfiltration system;
• an air stripper system in fluid communication with the first pass reverse osmosis system;
• and
• a second pass reverse osmosis system in fluid communication with the air stripper system.