This article presents the results of a pilot‐scale evaluation of an advanced oxidation process that utilizes hydrogen peroxide and ozone. Treatment efficiency was determined as a function of the hydrogen peroxide‐to‐ozone dosage ratio, ozone dosage, and contact time. The ozone mass transfer characteristics of the process were also investigated. Comparison with other treatment technologies indicates that advanced oxidation can be a cost‐effective treatment process for controlling the common chlorinated organics found in groundwater.
The size of the filters used in a water treatment pilot study has a big impact on the cost of the pilot facility itself. It has been shown that errors can be avoided by maintaining an adequate ratio between filter column diameter and media diameter (D/d). The purpose of this study was to investigate the effect of this same scaleup parameter on the filtration process itself. Five pilot‐filter columns were operated in parallel with a full‐scale filter. In these tests, (D/d) ranged from 26:1 for the smallest column to 6,000:1 for the full‐scale filter. No significant differences were observed in the mean rate of head loss buildup, the effluent turbidity, or the effluent particle count for any of the filters, although the variance in the estimate of rate of head buildup was much greater for the smallest filter. A D/d ratio of 50 or greater is recommended for most pilot‐filter operations.
Filter performance has traditionally been characterized by effluent quality (usually turbidity) and net water production. The common yardstick for measuring the latter has been the length of filter run, but other criteria for assessing filter performance, such as filtration rate and backwash volume, can provide more useful data.
Pilot plant tests, undertaken in Utah, indicate that direct filtration produces a high quality water with lower capital and operation costs than conventional treatment.
Typical pilot studies may slightly underestimate clean‐bed head loss in full‐scale filter beds.
The weight of media per unit of filter area cannot be directly measured in a full‐scale filter bed as it can be in a pilot‐scale filter column. Thus the porosity of a full‐scale bed of filter media cannot be readily calculated, and determinations of the porosity in full‐scale filters are rarely reported. In this study the porosity of one full‐scale monomedia filter bed was estimated by comparing the head loss in a full‐scale filter with the head loss in a pilot‐scale filter, when both used the same anthracite media. The full‐scale filter contained uniform anthracite media with an effective size of 1.5 mm loaded to a depth of 6 ft (1.8 m). The gradual termination of the backwash flow produced more consistent porosities in pilot‐scale filter beds. The porosity of the full‐scale filter bed was about 48 percent, somewhat lower than that expected in pilot‐scale columns. Thus, full‐scale designs based on pilot data may underestimate clean‐bed head loss.
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