A Centerville, Texas, man who used to run a Shreveport company has been sentenced to five years in prison.  55-year-old John Tuma has also been sentenced to three years supervised release and a $100-thousand fine.  He was immediately remanded into the custody of the U-S Marshal.  Tuma was convicted by a federal jury back in March for discharging untreated wastewater directly into the Red River and into the Shreveport sewer system while he ran Arkla Disposal Services on Highway One South.