MWWTP Effluent FM Surge & Transient Design Build Services (UN 1282)

The Board of Commissioners for Charles County, Maryland is requesting design-build proposals for construction of a new 40-foot diameter standpipe with associated surge-management infrastructure at the Mattawoman Wastewater Treatment Plant, with proposals due October 1, 2026 at 11:00 a.m. A Minority and Women-Owned Business Enterprise (MWBE) subcontractor participation goal of 33.96% applies. Prevailing wage rates apply to this County-financed project exceeding $500,000.

The scope encompasses hydraulic modeling, design and fabrication of a 40-foot diameter welded steel standpipe with radiographic level 3 welds, construction of three concrete valve vaults (influent, effluent, bypass), installation of 42-inch minimum diameter ductile iron influent and effluent pipes, temporary bypass systems capable of passing 60 million gallons per day at 150 psi, electrical and controls integration, sump pumps, drainage systems, pavement demolition and restoration, and comprehensive operations and maintenance manuals and operator training. The design-builder must obtain all permitting (Charles County Development Services, Building, Grading, Demolition; Maryland Department of the Environment Water and Sewerage Construction; Federal Aviation Administration obstruction evaluation) and maintain continuous effluent pump station flow during construction. Materials include ductile iron pipe for 4-inch and larger applications, Schedule 80 PVC for buried piping under 4 inches, and Type 316 stainless steel for above-grade exterior piping. Design deliverables include 60%, 90%, and 100% design packages; the contractor must submit a detailed Critical Path Method schedule within 75 days of Notice to Proceed and conduct 14-day consecutive startup testing using actual process fluids before system delivery.

The contract term is 690 consecutive calendar days from Notice to Proceed (design not to exceed 270 days; construction not to exceed 420 days). The site is located at 5310 Hawthorne Road, La Plata, Maryland 20646. Performance and Payment Bonds equal to 100% of contract price are required. Evaluation weights: design-build team qualifications 5 points, construction experience 5 points, key personnel experience 10 points, technical approach 20 points, construction schedule 5 points, safety risk management 5 points, price 50 points. The lead design firm must have a minimum 15 years' experience with three completed design projects exceeding $2 million each at municipal wastewater treatment plants rated 5 mgd or greater, including at least one design-build project; the lead construction firm requires 10 years' experience with three similar projects exceeding $2 million each, including at least one design-build project. The Design-Build Project Manager must have 15 years' experience; discipline leads must hold current Maryland Professional Engineer or Architect licenses with 10 years' experience. A non-mandatory pre-proposal meeting is scheduled July 30, 2026 at 11:00 a.m. via teleconference (registration due July 29). A non-mandatory site visit is scheduled August 13, 2026 at 9:00 a.m. Questions are due August 20, 2026 at 12:00 p.m.