Views
4 months ago

galvis

Water treatment

and operational

and operational considerations Pardón (1989) advised the exploration of alternative PCA with lower drainage velocities. Collins et al (1994) reported drainage velocities in the range of 10 to 37 mh -1 in hydraulically cleaning DGF and UGF pilot units with overall cleaning efficiency of stored solids of only 6.4% removed in DGF and 32% removed in UGF. They also made changes to flow patterns inside the gravel beds by changing drainage velocities in their procedure. 3.2.4.3. Run lengths, headlosses, and Silt test in SSF units Run lengths and productivity in SSF units. Run lengths between partial cleaning activities (scraping) were determined by maximum hydraulic head (0.8 m) available at SSF pilot units. During the first two test periods SSF units had a filtration rate of 0.10 mh -1 and run lengths in a range from 26 (for SSF 2 ) to 51 days (for SSF 1 ). SSF run lengths during test periods III and IV are summarised in figure 3.24. These results suggest that to obtain mean run lengths above 30 days SSF units operating at 0.15 mh -1 should have influent SS, turbidity, and total iron concentrations with mean values lower than 2 mgl -1 , 8 NTU, and 0.3 mgl -1 respectively, as shown in the table included in figure 3.24. However, other factors such as nature and size of particles, water temperature, nutrient levels, solar radiation, and O&M practices will also influence final results at local level. Those SSF units receiving poorer quality water may show higher removal efficiencies in some water quality parameters but will require higher O&M activities. 100 10 Units 1 0 UGFS SSF 1 UGFL SSF 2 MHGF SSF 3 HGF SSF 4 DGFS SSF 5 Susp. solids (mg/l) Turbidity (NTU) Run length (days) Parameter Statistics UGFS UGFL MHGF HGF DGFS Suspended Solids (mgl -1 ) Mean (SD) 1.6 (1.9) 4.0 (3.7) 3.5 (3.5) 1.5 (1.9) 1.9 (2.2) Turbidity (NTU) Mean (SD) 7.3 (7.7) 13.0 (13.5) 11.9 (14.1) 5.8 (5.6) 8.3 (7.7) SSF 1 SSF 2 (1) SSF 3 (1) SSF 4 (1) SSF 5 Mean (SD) 30.4 (6.6) 24.3 (6.2) 23.7 (7.5) 37.4 (8.5) 33.2 (5.7) Run length (days) Minimum 23 13 15 27 28 Maximum 50 37 40 53 45 N (Data) 14 19 18 10 13 (1) These SSF units were taken out of operation earlier due total cleaning activities in their CGF lines Figure 3.24. Run lengths of SSF pilot units operating at 0.15 mh -1 . December 1991-April 1993. 121

SSF 2 (after UGFL) and SSF 3 (after MHGF) presented minimum run lengths of 13 and 15 days respectively. SSF 1 (after UGFS) and SSF 4 (after HGF) reached maximum run lengths of 50 and 53 days respectively. Therefore, SSF 2 had the lowest productivity (47 m 3 per m 2 of filtering surface area) in a run while SSF 4 reached the highest (191 m 3 m -2 ) in a run. SSF units processing low turbidity surface waters in the USA had a water production in the range 112 to 650 m 3 m -2 during filtration runs lasting from a week to a year with an average value around 1.5 months (Letterman, 1991). Headloss developments in SSF units. Examples of headloss developments are shown in figure 3.25. Typically, headlosses in SSF pilot units at Puerto Mallarino developed initially an approximately linear shape, and later they took on an exponential shape (figure 3.25-A). This figure shows that in the first 80% of the SSF run length headloss developed around 40% of the total available hydraulic head and the remaining 20% of run length resulted in another 60% of headloss. Figure 3.25-B shows an exponential headloss development of a SSF unit at Ashford Common in London (Woodward and Ta, 1988). Around 35% of headloss developed in the last 20% of filter run length. With results like those shown in figure 3.25 and similar findings with full-scale projects in Colombia it seems that the supernatant water layer heads in “conventional” SSF units could be reduced with little impact on running cost. Traditional supernatant water heads in the range 0.9 to 1.5 m (see table 2.4) could be reduced to values in the range 0.6 to 0.8 m, depending on local conditions. This recommendation would be more relevant in those development programmes in which running costs (mainly labour) are less critical than initial capital investment. Headloss fraction (hf/hfmax*100) A 100 90 80 70 60 50 40 30 20 10 SSF Pilot unit, CINARA Research Station, Puerto Mallarino, Cali. Colombia. Vf = 0.15 mh -1 Tmax = 50 Días Hmax = 0.80 m. 0 0 20 40 60 80 100 Time fraction (t/Tmax*100) Headloss Fraction (hf/hfmax * 100) B 100 90 80 70 60 50 40 30 20 10 0 SSF London Ashford Common Vf = 0.2 mh -1 Tmáx = 60 días Hmáx = 2.2 m. 0 20 40 60 80 100 T im e fraction (t/T m ax * 100) Figure 3.25. Typical headloss developments throughout SSF runs. A-SSF 1 at Puerto Mallarino, September 18 to November 5 1992, and B-SSF 9 at Ashford Common Works, October 2 to December 31 1986 (Woodward and Ta, 1988). Silt test in SSF units. Silt test results of sand samples taken from SSF filter bed surfaces before and after partial cleaning (scraping) activities during test periods II, III, and IV are summarised in table 3.28. During test period II SSF units were operating at 0.1 mh -1 . Silt test results from sand samples before scraping seem to have a tendency to increase from period II to III. Then they decrease from period III to IV, but at a slower rate in SSF 1 (after UGFS) 122

Pall Aria™ AP-Series Packaged Water Treatment ... - Pall Corporation
Water Treatment Improvements and Plant Capacity ... - Ohiowater.org
The best solutions in water treatment - Istobal
Council Bluffs Water Works South Water Treatment Plant – Planning ...
Technical Advances in the Treatment of Water and Air for ... - IAAPA
Weatherford in Waste Water Treatment (WWT)
Drinking Water Treatment for Small Communities - P2 InfoHouse
P01073 ZTF - ZEKS Compressed Air Solutions
Freshwater-Aquarium-Manual
Systematic Approach to Water Treatment Plant ... - Ohiowater.org
Water treatment for the aquaculture industry
Water Quality Report - 2010 - Presidio Trust
High Heat Filtration with Industrial Air Filter Bags
advanced water treatment and recycling processes - International ...
Advances in Water Treatment and Enviromental Management
Comline - First for Filters Catalogue_web.compressed
Artificial ground-water recharge at Peoria, Illinois. - Illinois State ...
Screen Filtration for Ballast Water Treatment Applications - Cross ...
Advanced oxidation process treatment of membrane filtration ...
waste water treatment at the Hilltop Brewery - Great Lakes Water ...
Wastewater Treatment Options - Saudi Arabian Water Environment ...
PDF (1.43 MB) - P84.com
end of 2010_sales_catalog_12x18.indd - Ultrafryer Systems
Download Brochure - Excalibur Water Systems
R.E. Prescott Company Water Treatment Catalog
(DBP) Violations at Small Water Treatment Systems ... - Ohiowater.org
Activated Carbon in Potable Water Treatment - Norit