Port of Portland's Living Machine

The Living Machine at the Port of Portland Headquarters in Oregon is a water processing/filtration system that utilizes man made wetland environments to "process" water. The "process" is typically meant to clean dirty water in order to make it more usable (but not potable). The Port of Portland's Living Machine uses both Tidal Flow and Vertical Flow wetland environments. Tidal and Vertical refer to the manner in which water travels through the filtration cells. Tidal flow cells are allowed to overflow into their neighboring cells while Vertical flow cells function on gravity; as soon as water reaches the outlet, water will flow into the next cell. The other difference is that Vertical flow cells tend to have aquatic vegetation whereas tidal flow cells have emergent plants. Generally speaking, the vegetation is used to remove nitrate that is produced by the bacteria that eats pathogens found in "dirty" water. The vegetation is the point where users get to interact (visually) with the system. However most of the work is done by bacteria that is found living in the aggregate-filled cells and by two other un-seen components. The first is the Primary Tank that filters effluent. Usually to remove solids from the water. The second is the disinfection system that is used to "polish" the water during the final stages before it us stored for reuse. The Port of Portland uses ultraviolet light and chlorination for this process. This case study uses the water stored in the reuse tank for toilets and evaporative cooling. The system was designed to process 5000 gallons of water a day. The contents of the primary tank are emptied out before the beginning of the next cycle.