Advanced Treatement Which toxic gas is found mainly in groundwater, is heavier than air, and is odoriferous? Tags: Certification Exam Prep, Distribution System, Hydrogen sulfide, Water Treatment Read more articles Previous PostFiltration Next PostBackflow Prevention Devices You Might Also Like Flocculation July 4, 2017 Mastering Water Math February 22, 2019 How to Calculate Trench Volume in Cubic Feet – Distribution August 30, 2017 Post author: Post published:January 20, 2017 Post category:Certification Exams / Distribution / Water Treatment