The city of Bowie will step up efforts to improve its two-year-old sewage treatment plant under a consent agreement signed last week, and the state health department will withdraw its $25,000 fine against the city for allegedly dumping improperly treated waste water and sludge into the Patuxent River.

The Maryland Water Management Administration lodged a complaint against the city in April, citing 49 incidents of sludge spilling into the river and 88 violations of a surface water discharge permit between November 1983 and January 1984.

At the time of the complaint, the administration charged that the plant did not have an adequate waste disposal plan. The agreement requires Bowie to build a temporary winter sludge storage site and find a long-term disposal site.

The city currently has a three-year permit to store sludge in Anne Arundel County.

Bowie agreed to participate with the Washington Suburban Sanitary Commission in a long-term sludge disposal study and will work to better the quality of the Patuxent River by improving the Allen Pond and Marne Lane storm drain facilities. The city plans to reimburse the state for a portion of Bowie area inspection costs during the past two years that were intended to improve Patuxent water quality. City Manager G. Charles Moore said Bowie allocated about $100,000 in its budget for the improvements.