NY -- Standard&Poor's CreditWire 4/14/98 – Standard&Poor's today assigned its double-'A'-minus rating to Trinity River Authority, Texas' $84.5 million regional wastewater system revenue improvement refunding bonds series 1998B dated April 15, due Aug. 1, 2017. The bonds are scheduled to sell April 23, 1998. At the same time, Standard&Poor's affirmed its double-'A'-minus rating on the authority's revenue bonds. The rating on the Trinity River Authority's Central Regional Wastewater System reflects: -- The credit strengths of the member cities, -- Low treatment rates, and -- Adequate treatment capacity until 2010. Wastewater from all or portions of 20 cities and the Dallas-Fort Worth Airport is collected and treated within the central regional wastewater system, serving a