Full Description

A new particle characterization technology called Dynamic Particle Analysis (or DPA) provides a tool forstudying WTP process dynamics. DPA makes use of digital microscopy, image analysis, and a fluidhandling system to count, size, and image particle populations in flowing liquids. Primary advantages ofthis technique include speed, sensitivity, and accurate detection of high particle concentrations (10sup6/sup permL) permitting application throughout all stages of the WTP. Additionally, DPA technology provides newinsights into process-related particle structure by virtue of the particle images made available.This study summarizes experimental results from applying DPA to characterize full-scale WTP streamsduring normal process conditions. Particle characterization was carried out at each stage of thetreatment process including raw water influent, mixing chambers, settling basin effluent, dual-media filtereffluent, chlorine contact basin, and plant effluent. Results were correlated and compared to data fromonline turbidity meters and online particle counters. In addition, filter effluent changes throughout atypical filter hydraulic step-change (10ML/day to 20ML/day) were analyzed.It was found the DPA unit detected three to five times more particles/ml relative to the online ParticleCounters over the same size measurement range. When used to evaluate the filter effluent response tothe step increase in flow rate, the DPA reported a transient increase from 309 to 1355 particles/ml(particles 5m increased from 10 to 26) while the turbidity readings reported a very small change ofonly 0.02 NTU before stabilizing. It was also found that through application upon the raw water, mixingchamber samples, and settled water, the DPA technology was able to provide visibility into the dynamicsof particle formation and removal throughout the coagulation/flocculation/sedimentation process andprovide useful data that may be used to evaluate and ultimately predict particle removal efficiency undervarious loading and operational conditions.Future work will involve applying DPA to study treatment plant particle removal as influenced byseasonal effects such as water temperature and raw water microbial constituents, and Pilot-scaleexploration of process impairments such as non-optimal coagulant dose, pH, and polymer dose.Additionally, filter effectiveness throughout a typical filter cycle including filter ripening phase,performance throughout operational phase, early breakthrough and late breakthrough phases will beinvestigated. Includes tables, figures.

Product Details

Edition: Vol. - No. Published: 11/15/2004 Number of Pages: 12 File Size: 1 file , 1.7 MB