INTERACTION OF CLARIFIERS WITH OTHER FACILITIES

Primary and secondary clarifiers are inseparable and integral part of every conventional wastewater treatment plant. Their performance efficiency is affected by the upstream wastewater collection and treatment facilities and has a significant impact on downstream biological treatment and solids handling facilities. The work addresses the interaction of plant clarifiers with the wastewater collection system, pretreatment facilities, the activated sludge treatment process and the solids handling facilities. More specifically, this work discusses the effect of wastewater collection system type on clarifier design and various means for mitigation of transient flow impact on clarifier performance, such as peak flow reduction measures in the collection system; flow equalization; use of high-rate solids separation technologies; relationship between clarifier depth and its transient flow handling capacity; and mitigation of transient flow impact by monitoring and control of the overall solids inventory in the activated sludge system. The effect on primary clarification on nutrient removal in conventional and enhanced nitrogen and phosphorus removal systems is also discussed and guidelines for clarifier design for chemical and biological nutrient removal are presented. This work also discusses the interaction of plant primary and secondary clarifiers with the sludge thickening, stabilization and dewatering facilities.