North Liberty Wastewater Phase II – Update

North Liberty, Iowa

December 1, 2016

Phase II improvements are progressing. Over the past month, the Biosolids Dewatering Facility was started up and is now operational. The dewatering equipment consists of a rotary fan press, manufactured by Fournier. It is designed to process 2.0% aerobically digested biosolids produced by the membrane bioreactor (MBR) wastewater treatment plant and is sized for 106,750 gallons of biosolids processed in 30 hours per week. The rotary fan press is expected to dewater biosolids to an average of 14.0% solids. Dewatered biosolids will be stored in a new storage building.

Biosolids Dewatering-Fourneir Fan Press

Biosolids Dewatering-Fourneir Fan Press

Biosolids Dewatering - Dewatered Biosolids

Biosolids Dewatering – Dewatered Biosolids

Biosolids Dewatering - Building Exterior

Biosolids Dewatering – Building Exterior

Dewatered Biosolids Storage Building

Dewatered Biosolids Storage Building

The existing MBR treatment capacity is being expanded with the Phase II Improvements project by adding a 4th membrane treatment train, which is General Electric’s (GE) LEAPmbr process. Over the past few weeks, GE has been onsite performing startup services for the new membrane train and the support equipment.

MBR - Permeate Pump & MBR Train 4 instrumentation & piping

MBR – Permeate Pump & MBR Train 4 instrumentation & piping

Support equipment includes two additional mixed liquor return pumps for pumping mixed liquor to the membrane trains, a rotary lobe pump for pulling permeate water through the membrane, additional positive displacement blower, expansion of the existing chemical feed system, and instrumentation.

MBR - Mixed Liquor return pump

MBR – Mixed Liquor return pump

Installation of four membrane cassettes in the 4th membrane train is currently underway. Startup of the 4th train is expected to be complete this month.

North Liberty MBR Train

North Liberty MBR Train

The contractor is also working on improvements in the aeration basins so the plant can achieve nitrogen and phosphorus removal. The treatment facility is expected to produce an effluent with 1 mg/L total phosphorus and 10 mg/L total nitrogen. Work in the existing basins will continue through winter and spring.

Existing Aeration Basins modified for conversion to BNR

Existing Aeration Basins modified for conversion to BNR

Improvements to the existing preliminary treatment building and process will commence this winter; that will include installation of a flex-rake bar screen, an increase in raw wastewater pumping capacity, and installation of odor control equipment.

The Phase II Improvements project is scheduled to be substantially complete June 2017 with completion by August 2017. Upon completion, the facility will have a rated capacity of 4.43 MGD.

FOX Engineering is an environmental engineering firm based in Ames, Iowa. We specialize in water and wastewater solutions for our diverse municipal and industrial clients. Our work varies in size and scope and can be found throughout the Midwest and beyond.