Dynamic model of a municipal wastewater stabilization pond in the arctic

Waste stabilisation ponds (WSPs) are the method of choice for sewage treatment in most arctic communities because they can operate in extreme climate conditions, require a relatively modest investment, are passive and therefore easy and inexpensive to operate and maintain. However, most arctic WSPs are currently limited in their ability to remove carbonaceous biochemical oxygen demand (CBOD), total suspended solids (TSS) and ammonia-nitrogen. An arctic WSP differs from a 'southern' WSP in the way it is operated and in the conditions under which it operates. Consequently, existing WSP models cannot be used to gain better understanding of the arctic lagoon performance. This work describes an Arctic-specific WSP model. It accounts for both aerobic and anaerobic degradation pathways of organic materials and considers the periodic nature of WSP operation as well as the partial or complete freeze of the water in the WSP during winter. A uniform, multi-layer (ice, aerobic, anaerobic and sludge) approach was taken in the model development, which simplified and expedited numerical solution of the model, enabling efficient model calibration to available field data.