A new particle characterization technology called Dynamic Particle Analysis (or DPA) provides a tool for
studying WTP process dynamics. DPA makes use of digital microscopy, image analysis, and a fluid
handling system to count, size, and image particle populations in flowing liquids. Primary advantages of
this technique include speed, sensitivity, and accurate detection of high particle concentrations (>10<sup>6</sup> per
mL) permitting application throughout all stages of the WTP. Additionally, DPA technology provides new
insights 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 streams
during normal process conditions. Particle characterization was carried out at each stage of the
treatment process including raw water influent, mixing chambers, settling basin effluent, dual-media filter
effluent, chlorine contact basin, and plant effluent. Results were correlated and compared to data from
online turbidity meters and online particle counters. In addition, filter effluent changes throughout a
typical 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 Particle
Counters over the same size measurement range. When used to evaluate the filter effluent response to
the step increase in flow rate, the DPA reported a transient increase from 309 to 1355 particles/ml
(particles >5µm increased from 10 to 26) while the turbidity readings reported a very small change of
only 0.02 NTU before stabilizing. It was also found that through application upon the raw water, mixing
chamber samples, and settled water, the DPA technology was able to provide visibility into the dynamics
of particle formation and removal throughout the coagulation/flocculation/sedimentation process and
provide useful data that may be used to evaluate and ultimately predict particle removal efficiency under
various loading and operational conditions.
Future work will involve applying DPA to study treatment plant particle removal as influenced by
seasonal effects such as water temperature and raw water microbial constituents, and Pilot-scale
exploration 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 be
investigated. Includes tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 12 |
| Published : | 11/15/2004 |
