Construction Management for a Storage and Shipping Facility

Soda ash can be difficult to contain. During ship and railcar loading and unloading operations, small amounts of this fine powder can escape, land on the ground, and be picked up by stormwater runoff. This can result in elevated pH in stormwater, which triggered NPDES stormwater permit corrective action requirements. This soda ash storage and shipping facility engaged MFA to design and construct a stormwater pH adjustment system consisting of a pump station, carbon dioxide storage, injection and reaction tanks, and associated conveyance system modifications. This treatment system has reduced the pH levels in stormwater discharged from the site to the Willamette River to below the stormwater permit benchmarks.

Several years later, MFA designed and constructed additional treatment system components to reduce metals and polycyclic aromatic hydrocarbons in the effluent. These included detention and settling tanks and a passive, adsorptive media filter. The improvements to the treatment system met the NPDES stormwater permit benchmarks as well as Portland Harbor source control requirements.

MFA also designed a bioinfiltration facility to treat runoff from another potion of the site via plant uptake and adsorptive media filtration prior to infiltration into the ground.

MFA provided construction oversight for all phases of treatment system construction and coordinated the work of a number of contractors and inspectors, ranging from the treatment system vendors, the carbon dioxide vendor, the pump vendor, geotechnical and structural engineers, and an electrical contractor, to a general contractor that constructed the pump station, concrete pads, tanks and filter. MFA also ensured that the contractors’ operations minimized impact to the client’s ongoing shipping operations and complied with the port’s security requirements.

The project was permitted through the City of Portland, coordinated with the Port of Portland (the property owner), and constructed in 2018.