New wastewater mandates by the Iowa DNR could mean improvements to the city of Pella's sanitary sewer collection system. Public Works Director Denny Buyert says the DNR is requiring the city to eliminate wastewater bypasses by October 2012. The firm Howard R. Green will conduct a study of the system to see what improvements could be necessary. A similar study was conducted in 1998 and found that upgrades could cost about $4 to $5 million. Buyert says the new report is expected by October of this year.