Challenge
- Application: Treatment of domestic sewage from a 42-person tent camp for discharge to the ground surface
- Capacity: 1,500 gpd (5,700 lpd)
- Location: Remote mineral exploration camp in the Alaska Range, Denali Highway, Alaska
- Commissioned: June 20, 2018
Summers in Alaska are intense, but short. A mineral exploration company had planned a full season of helicopter-supported drilling on a property in the Alaska Range. A logistics company had put together a 42-man tent camp that included a kitchen, wash car (urinals, showers, clothes washers, utility sinks), and the associated facilities. Exploration was scheduled to start soon, commitments having been made for a helicopter, drill rig, and crew to arrive. The only thing left to be determined was how to treat and dispose of wastewater.
Precious time had been lost searching for a location for a conventional septic system. The small campsite was in a low area confined by a hill on one side and a river on the other. No suitable location could be found, nor any viable alternative identified. High pumping fees to transport sewage off site for disposal seemed inevitable.
Solution
The client was referred to Lifewater Engineering Company, a Veolia channel partner in Fairbanks, Alaska. Lifewater assessed the situation and suggested a membrane bioreactor (MBR) with surface discharge since there was a vegetated area near the camp that could accept and disperse treated effluent. The Alaska Dept. of Environmental Conservation’s (ADEC) verbal concurrence with this plan triggered final design. Because this system would only operate seasonally in the warmer months, an insulated system was not needed, simplifying design and fabrication. The MBR design came together quickly since Lifewater and Veolia engineers had recently collaborated to develop a generic design for a small MBR based on ZeeWeed* technology. Final design, plan review & approval, procurement, and fabrication proceeded concurrently, followed closely by delivery, commissioning, and operator training. In less than three weeks, the project went from purchase order to an operational system.
Process overview
Sewage is collected from the kitchen and wash car in a lift station. The lift station pumps wastewater to a 1500-gallon trash tank; from which it flows by gravity to a 1500-gallon, aerated bioreactor. A submersible pump transfers mixed liquor from the bioreactor to a separate membrane tank which contains one
ZeeWeed hollow fiber UF membrane cassette.
A pump pulls filtrate through the ZW500S and discharges it into a filtrate tank. A submersible pump in the filtrate tank intermittently discharges treated effluent to a vegetated area. The following table details the required discharge limits, and the actual values recorded.
Result
Lifewater designs rugged systems that must work with minimal intervention. Veolia’s ZeeWeed 500S single cassettes are proven and robust that are ideally suited for building Membrane Bioreactors.
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