Sludge Handling System for Dewatered Biosolids and Composting Additives Ft. McMurray, Canada

General Description

The City of Fort McMurray completed the construction of a new sewage treatment plant designed to be expanded in phases to meet the housing needs of the city’s rapidly growing population. Phase 2 was recently completed and serves a population of 100,000. Phase 3 will bring the plant capacity up to handling a capacity of 133,000 people in the near future. As part of the project, the City needed a highly reliable Sludge Handling System (SHS) to replace a system installed in 2006 that did not achieve that design goal.

Dewatered municipal biosolids (Sludge) is collected by a shaftless conveyor from two centrifuges with a provision for a future additional unit. The Collection conveyor collects sludge from the centrifuges and transfers it to an inclined conveyor that discharges material to a storage pad. Then, the sludge is transferred to a mixing bin where composting additives are introduced and thoroughly mixed. The mixed material discharges to a 32-inch diameter shaftless conveyor that transfers the blended material to a second storage pad. From this pad, the material is moved to storage bunkers where it composts until the mixture has the desired characteristics for reuse.

Design Parameters

Type of Sludge:	Dewatered Municipal Wastewater Sludge
Material density – max:	1,031	kgs/m³
Material desnsity – min:	950	kgs/m³
Solids, percent by weight:	23-28	% TS
Capacity (max):	46.25	wet tonnes/hour (wtph)
Capacity (max):	45	m³/hr
Ambient temperature (max):	37	° C
Ambient temperature (min):	5	° C

Type of Sludge:	Dewatered Municipal Wastewater Sludge combined with wood chips
Material density – max:	640	kgs/m³
Material desnsity – min:	500	kgs/m³
Solids, percent by weight:	45-60	% TS
Capacity (max):	82.5	wet tonnes/hour (wtph)
Capacity (max):	130	m³/hr
Ambient temperature (max):	37	° C
Ambient temperature (min):	5	° C

Fort McMurray, Alberta

Consulting Engineer

Associated Engineering Alberta, Ltd. Penticton, BC

KWS Advantages

As a design, engineering and manufacturing company with expertise with shafted and shaftless screw conveyors, KWS quickly identified the problems with the existing shafted conveyors that were provided by another manufacturer. Engineers from KWS met with the Consulting Engineer and site personnel at Wood Buffalo to fully understand the application and redesigned the Sludge Handling System with the correct technologies.

KWS provided a complete system including large diameter shaftless screw conveyors, structural supports, as well as on site commissioning and operator training. Our ability to accurately design and build the conveyor system allowed Wildstone Construction to demolish, remove the old system, install, commission and test the KWS system within the maximum 5-day shutdown window available. The City of Ft. McMurray was up and running without having to divert sludge from the plant, saving thousands of dollars in costs.

Special Features

KWS designed the Centrifuge Collection System with an inline transfer from the Collection Conveyor to the Inclined Conveyor to save space and reduce the angle of incline. The existing system utilized shafted screw conveyors that were a continual operations and maintenance problem. The City had never been able to run one of two of the existing centrifuges at capacity without blocking the conveyors. KWS redesigned the Centrifuge Collection System using shaftless screw conveyors and dramatically improved the system capacity within the same tight space constraints. They now can run both centrifuges at full capacity and still have additional capacity to add a third centrifuge in the future.