Effects of Total Suspended Solids Loading on Short-Term Fouling in the Treatment of Secondary Effluent by an Immersed Ultrafiltration Pilot System

摘要

This study examined the performance of a pilot-scale immersed ultrafiltration system using secondary effluent as a feed source, with particular emphasis on the role played by total suspended solids (TSS) on short-term fouling rates within permeation cycles. Key secondary effluent quality characteristics, such as ionic composition and total/ colloidal organic carbon content, remained reasonably stable during the course of the study. However, TSS loads in the secondary effluent were correlated with the extent of within-cycle fouling. This relationship existed irrespective of membrane packing density or the operating flux, although the latter parameter did control the rate at which within-cycle fouling occurred. Although the complex causes of ultrafiltration membrane fouling during tertiary treatment over the long term remain poorly understood, TSS levels in the feed may offer a simple means of better predicting within-cycle spikes in transmembrane pressure. Based on historical and seasonal trends, or both, of TSS loads in the secondary clarifiers of a given wastewater treatment plant, periods requiring an increased frequency of backpulses or recovery cleanings may be identified before implementation of full-scale tertiary ultrafiltration systems.