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Table 1. Evolution of turbidity z, pH, and temperature T (°C) for raw water (a); optimal chemicals doses for performed CC jar tests in the laboratory (b); and water characteristics after jar tests (c) (numbers between brackets present the corresponding removal efficiency (%))

Table 1 Evolution of turbidity z, pH, and temperature T (°C) for raw water (a); optimal chemicals doses for performed CC jar tests in the laboratory (b); and water characteristics after jar tests (c) (numbers between brackets present the corresponding removal efficiency (%))

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Table 3. Evolution of OM (as mg O2 L”!) for raw water (a) and treated water in SAS (b) with its removal (c) Table 2. Evolution of NHa*, PO4*, NOx and NOz (mg L”!) for raw water (a) and treated water in SAS (b) (nd: not determined)
Table 3. Evolution of OM (as mg O2 L”!) for raw water (a) and treated water in SAS (b) with its removal (c) Table 2. Evolution of NHa*, PO4*, NOx and NOz (mg L”!) for raw water (a) and treated water in SAS (b) (nd: not determined)
Table 4. Evolution of Al and Fe (mg L"!) for raw water (a) and treated water in SAS (b) Table 5. Evolution of some parameters of the Boukerdene Dam’s water at different levels of the Dam (nd: not determined
Table 4. Evolution of Al and Fe (mg L"!) for raw water (a) and treated water in SAS (b) Table 5. Evolution of some parameters of the Boukerdene Dam’s water at different levels of the Dam (nd: not determined
Table 6. Evolution of Ca2+, Mg2+, Cl, HCOz and SO? (mg L~!) for raw water and treated water in SAS (b)
Table 6. Evolution of Ca2+, Mg2+, Cl, HCOz and SO? (mg L~!) for raw water and treated water in SAS (b)
at 1 m (255 774 and 452 750 cells mL", respectively). At 10 m under the surface, algae number is practically the same in May and June. Fig. 1 shows the variation of raw water's algae number from May to August. For June and August, the algae number increases due to the fact that this period coincide with strong light, high surface-water temperatures, calm weather, and a_ stable stratification of the water column (Wulff et al., 2007). Fig. 2 shows the variation of settled water's after C/F) algae number from May to August in SAS. Fig. 3 shows the variation of filtered water's after C/F and sedimentation) algae number from May to August in SAS. Fig. 4 shows the variation of treated water's (after C/F, sedimentation, and chlorination) algae number from May to August in SAS. As seen in Figs. 2-4, algae number evolution from May to August is globally similar at the different steps of the treatment. During this study, as seen in Table 4, water treatment using alum has no effect on Al presence in the treated water due to the fact that raw water did not present Al and the precision of the jar tests. The iron concentrations are always under the standards 0.3 mg L"!). Table 5 presents the evolution of some parameters of the Boukerdene Dam’s water at different levels of the Dam. This control was performed in 2007's summer (17" July, 32°C) in order to check the Dam stratification after the bad taste apparition in the raw water. When the under surface level of water increase, turbidity and OM increase. Table 6 presents the evolution of Ca?*, Mg?*, Cl, HCOz and SO,” (mg L"!) for raw water and treated water in SAS.
at 1 m (255 774 and 452 750 cells mL", respectively). At 10 m under the surface, algae number is practically the same in May and June. Fig. 1 shows the variation of raw water's algae number from May to August. For June and August, the algae number increases due to the fact that this period coincide with strong light, high surface-water temperatures, calm weather, and a_ stable stratification of the water column (Wulff et al., 2007). Fig. 2 shows the variation of settled water's after C/F) algae number from May to August in SAS. Fig. 3 shows the variation of filtered water's after C/F and sedimentation) algae number from May to August in SAS. Fig. 4 shows the variation of treated water's (after C/F, sedimentation, and chlorination) algae number from May to August in SAS. As seen in Figs. 2-4, algae number evolution from May to August is globally similar at the different steps of the treatment. During this study, as seen in Table 4, water treatment using alum has no effect on Al presence in the treated water due to the fact that raw water did not present Al and the precision of the jar tests. The iron concentrations are always under the standards 0.3 mg L"!). Table 5 presents the evolution of some parameters of the Boukerdene Dam’s water at different levels of the Dam. This control was performed in 2007's summer (17" July, 32°C) in order to check the Dam stratification after the bad taste apparition in the raw water. When the under surface level of water increase, turbidity and OM increase. Table 6 presents the evolution of Ca?*, Mg?*, Cl, HCOz and SO,” (mg L"!) for raw water and treated water in SAS.
Table 7. Algae (cells mL!) vertical distribution in Boukerdene Dam’s (1, 5 and 10 m under the surface) and raw water s algae number (“under the surface) In May, the algae number at 5 m under the surface is greater than at 1 m (655 605 and 393 951 cells mL!, respectively). On the contrary, in June the algae number at 5 m under the surface is lower than
Table 7. Algae (cells mL!) vertical distribution in Boukerdene Dam’s (1, 5 and 10 m under the surface) and raw water s algae number (“under the surface) In May, the algae number at 5 m under the surface is greater than at 1 m (655 605 and 393 951 cells mL!, respectively). On the contrary, in June the algae number at 5 m under the surface is lower than
On the other hand, water treatment processes pre-chlorination (sodium hypochlorite), C/F, filtration, and post-chlorination] are apparently efficient in the algae removal (more than 95%, as seen in Table 8) since sodium hypochlorite as a powerful oxidant inhibits algae proliferation in the sedimentation basins and premature fouling in the filters. The algae number variation at any point of the Fig. 1. Variation of raw water's algae number from May to August
On the other hand, water treatment processes pre-chlorination (sodium hypochlorite), C/F, filtration, and post-chlorination] are apparently efficient in the algae removal (more than 95%, as seen in Table 8) since sodium hypochlorite as a powerful oxidant inhibits algae proliferation in the sedimentation basins and premature fouling in the filters. The algae number variation at any point of the Fig. 1. Variation of raw water's algae number from May to August
Fig. 3. Variation of filtered (after C/F and sedimentation) algae number from May to August in SAS
Fig. 3. Variation of filtered (after C/F and sedimentation) algae number from May to August in SAS
Fig. 2. Variation of settled (after C/F) algae number from May to Augustin SAS Fig. 4. Variation of treated (after C/F, sedimentation, and chlorination) algae number from May to August in SAS
Fig. 2. Variation of settled (after C/F) algae number from May to Augustin SAS Fig. 4. Variation of treated (after C/F, sedimentation, and chlorination) algae number from May to August in SAS
turbidity removal results); (2) tem produces accelerated proliferation fouling by some species which co depth in spite of 24 hours washing for the first and last, respec treatment chain is due to: (1) injected coagulant and flocculent doses variation (depending on jar tests perature increase of algae since settlers and filters are in the open air; (3) filters bio- onise the filters’ and; (4) pre and post-chlorination doses (0.4-0.8 and 0.8-1.2 mg L"! tively) variation depending on chlorine demand. Table 9 presents the distribution following classes of th e collected algae in the raw water. The qualitative sampling collection lets us determine the presence of 30 species which are distributed into 21 genera.
turbidity removal results); (2) tem produces accelerated proliferation fouling by some species which co depth in spite of 24 hours washing for the first and last, respec treatment chain is due to: (1) injected coagulant and flocculent doses variation (depending on jar tests perature increase of algae since settlers and filters are in the open air; (3) filters bio- onise the filters’ and; (4) pre and post-chlorination doses (0.4-0.8 and 0.8-1.2 mg L"! tively) variation depending on chlorine demand. Table 9 presents the distribution following classes of th e collected algae in the raw water. The qualitative sampling collection lets us determine the presence of 30 species which are distributed into 21 genera.
Table 8. Algal removal at different steps of the treatment chain in SAS (numbers between brackets present the corresponding removal efficiency (%))
Table 8. Algal removal at different steps of the treatment chain in SAS (numbers between brackets present the corresponding removal efficiency (%))
Table 9. Distribution following classes of collected algae in the raw water stratified reservoirs. Such accumulations may develop rapidly, and they may be of short duration. In many circumstances, blooms and accumulations are seasonal (WHO, 2006). DOUKReTaeHe Vadll Presents d 1€s5 AlVeLsllled phytoplanktonic population since three branches are not present: euglenophytes, pyrrophytes, and pheophytes and the found species are limited in comparison with Keddara Dam (Algeria) which presents a much diversified phytoplanktonic population (with 166 species which are distributed into 5 branches). The chlorophytes branch, which is dominant with 15 species, is followed by the chrysophytes branch (11 species), cyanophytes branch (3 species) and rhodophytes branch (1 species). Among the 21 identified genera in 8 samples during this study, seven are responsible of disagreeable tastes (earth taste) and odours: Anabaena, Oscillatoria, Synedra, Pediastrum, Scenedesmus, Cyclotella, and Peridinium even after water treatment in SAS. Disagreeable tastes and odours are directly attributed to the substances (metabolites) secretion by algae during their growth stage or indirectly to some cyanophycies which reject phenolic substances which are malodorous; but, during chlorination, these phenolic substances are transformed into chlorophenols which are toxic (Teksoy et al., 2008).
Table 9. Distribution following classes of collected algae in the raw water stratified reservoirs. Such accumulations may develop rapidly, and they may be of short duration. In many circumstances, blooms and accumulations are seasonal (WHO, 2006). DOUKReTaeHe Vadll Presents d 1€s5 AlVeLsllled phytoplanktonic population since three branches are not present: euglenophytes, pyrrophytes, and pheophytes and the found species are limited in comparison with Keddara Dam (Algeria) which presents a much diversified phytoplanktonic population (with 166 species which are distributed into 5 branches). The chlorophytes branch, which is dominant with 15 species, is followed by the chrysophytes branch (11 species), cyanophytes branch (3 species) and rhodophytes branch (1 species). Among the 21 identified genera in 8 samples during this study, seven are responsible of disagreeable tastes (earth taste) and odours: Anabaena, Oscillatoria, Synedra, Pediastrum, Scenedesmus, Cyclotella, and Peridinium even after water treatment in SAS. Disagreeable tastes and odours are directly attributed to the substances (metabolites) secretion by algae during their growth stage or indirectly to some cyanophycies which reject phenolic substances which are malodorous; but, during chlorination, these phenolic substances are transformed into chlorophenols which are toxic (Teksoy et al., 2008).
Table 10. Germs numbers per 100 mL found in different points of the treatment processes in SA! (TC: total coliforms; FC: fecal coliforms; FS: fecal streptococcus)
Table 10. Germs numbers per 100 mL found in different points of the treatment processes in SA! (TC: total coliforms; FC: fecal coliforms; FS: fecal streptococcus)
Table 13. Results of EC (August test (26/08/07), raw water characteristics: pH = 7.72; T (°C) = 25; c (NTU) =9.77; C (uS cm) not determined; OM (O2 mg L”!) = 1.28; algae number (cells mL"!) = 217 555; alum dose = 15 mg L’!, CP dose =0.015 mg L", numbers between brackets present the corresponding removal efficiency (%)) Fig. 5. Coagulation mechanisms for microcystin-LR removal (Ghemaout et al., 2010b)
Table 13. Results of EC (August test (26/08/07), raw water characteristics: pH = 7.72; T (°C) = 25; c (NTU) =9.77; C (uS cm) not determined; OM (O2 mg L”!) = 1.28; algae number (cells mL"!) = 217 555; alum dose = 15 mg L’!, CP dose =0.015 mg L", numbers between brackets present the corresponding removal efficiency (%)) Fig. 5. Coagulation mechanisms for microcystin-LR removal (Ghemaout et al., 2010b)
Table 11. Results of EC (June test (26/06/07), raw water characteristics: pH = 7.63; T (°C) =18.5; c (NTU) =6.94; C (uS cm'!) = 691; OM (O2 mg L'!) =2; algae number (cells mL’) = 467 450; alum dose = 20 mg L"!; CP dose = 0.025 mg L"!, numbers between brackets present the corresponding removal efficiency (%)) Table 12. Results of EC (July test (04/07/07), raw water characteristics: pH = 7.47; T (°C) = 21.3; c (NTU) = 4.42; C (iS cm!) = 796; OM (O2 mg L'!) = 1.2; algae number (cells mL’!) = 470 390; alum dose = 15 mg L!; CP dose =0.015 mg L"!, numbers between brackets present the corresponding removal efficiency (%))
Table 11. Results of EC (June test (26/06/07), raw water characteristics: pH = 7.63; T (°C) =18.5; c (NTU) =6.94; C (uS cm'!) = 691; OM (O2 mg L'!) =2; algae number (cells mL’) = 467 450; alum dose = 20 mg L"!; CP dose = 0.025 mg L"!, numbers between brackets present the corresponding removal efficiency (%)) Table 12. Results of EC (July test (04/07/07), raw water characteristics: pH = 7.47; T (°C) = 21.3; c (NTU) = 4.42; C (iS cm!) = 796; OM (O2 mg L'!) = 1.2; algae number (cells mL’!) = 470 390; alum dose = 15 mg L!; CP dose =0.015 mg L"!, numbers between brackets present the corresponding removal efficiency (%))
Related topics:
Natural Organic matter (NOM)Enhanced coagulation
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