NTH Consultants
Contact Us
  • Home
  • Markets
    • Energy Market
    • Industry Market
    • Water Market
    • Transportation
    • Community Development
  • Services
    • Geotechnical Engineering >
      • Geophysical Services
      • Mapping
      • Shoreline Services
      • Civil Site Engineering and Design
      • Construction Materials & Geotechnical Testing Services
      • Electric Substation Services
      • Geotechnical Engineering for Transportation Facilities
      • Underground Engineering Services
      • Subsurface Utility
      • Signature Projects
    • Environmental Services >
      • PFAS
      • Ecological Services
      • Environmental Health Services
      • Environmental Remediation Services
      • Environmental Compliance
      • Environmental Permitting
      • Environmental Site Assessments
      • Ecological Services for the Energy Market
      • Air Quality Permitting and Compliance
      • Brownfield Site Redevelopment
      • Environmental, Health & Safety Training for Employee Development
      • Hydrogeologic Studies
      • Landfill Related Services
      • Site Acquisition and Redevelopment
      • Storage Tank Services
      • Signature Projects
    • Facilities Engineering >
      • Decommissioning
      • Structural Condition Assessment Rehab
      • Bridge Engineering Services
      • Asset Management Services
      • Concrete Restoration
      • GIS Services
      • Masonry Evaluation Services
      • Pavement Engineering and Consulting
      • Roofing Technology Services
      • Structural Condition Assessment
      • Signature Projects
  • Projects
  • About Us
    • Mission + Core Values
    • Leadership
    • News and Events
    • Employee Portal
  • Webinars
    • Emergency Actions Plans Webinar
  • Careers
    • Why Join NTH
    • Who We Are
    • Career Opportunities
    • NTH Internship Program
  • Blog
  • Contact Us
Back to Signature Projects
Picture
Client:
Detroit Water and Sewerage
Department

Location:
Detroit, MI

Prime Consultant:
Malcolm Pirnie, Inc.

Total Project Budget:
$90 MM (Construction)
$10.5 MM (Design)

NTH Project Budget:
$1.2 MM

Start Date:
December 1998

Completion Date:
Spring 2004

DWSD Primary Clarifiers #17 and #18

Geotechnical, Environmental and Field Engineering

To comply with state requirements, the Detroit Water and Sewerage Department (DWSD) commissioned the design and construction of new primary clarifier capacity at the Detroit Wastewater Treatment Plant. The project was awarded to Malcolm Pirnie, Inc. in 1998. NTH was a major subconsultant to Malcolm Pirnie providing geotechnical engineering and related field engineering services.

Geotechnical Engineering
NTH performed the geotechnical investigation to gather design data for these structures, including assembly of historical subsurface information for adjacent projects, and performing additional test borings. We installed open-stand pipe piezometers in some test borings to measure artesian groundwater pressure in the hardpan and bedrock beneath the site to address this potential site challenge.

Environmental Engineering
NTH conducted an environmental sampling program to characterize the soils that would be excavated. We completed ash and soil sampling, analytical testing, evaluation of worker safety issues, and evaluation of disposal options.

Design Engineering
The design included two 250-foot diameter clarifiers, influent tunnels, sinking caisson shafts, and other underground structures. NTH designed an extensive construction staging plan to include acceptable factors of safety and to minimize impacts on existing structures and completed aspects of the work. Geotechnical instrumentation was specified to monitor soil and structure movement during construction. NTH used finite element analysis to analyze construction impacts on a portion of an existing tunnel, and then designed a reinforcement system using that data.

Construction Engineering
Construction is ongoing. NTH provided field engineering for underground construction including submittal review, construction claim review assistance, and as needed design services. NTH performed a condition survey and evaluation of a major primary influent tunnel while it was dewatered as part of the construction and found several large cracks that required repair. NTH designed the repair system, prepared plans and specifications, and provided the field engineering during the repair.

NTH reviewed geotechnical instrumentation data daily to evaluate the design and contractor operations. Changes to the construction procedures were made, allowing the contractor to be more aggressive in some areas, saving construction schedule and budget.