Essai de déferrisation naturelle d’une eau de source dans un village de Kabylie (Nord algérien)

This work is a contribution to the deferrization by natural aeration/decantation of spring water in Tazerouts village (south-east of the Tizi-Ouzou region, in northern Algeria), using a prototype installation (PI). The objective is to reduce the turbidity, the criterion used to assess the efficiency of deferrization, from 12.5 (initial value) to a maximum of 1 nephelometric turbiditu unit (NTU) before considering the extrapolation of the results obtained to the existing supply system dedicated to ferruginous water (SDFW). The latter provides water with a turbidity of 11 NTU which exceeds the potability threshold. The PI is composed of a series of 9 large plastic containers and 6 small plexiglass containers, placed alternately, generating a total settling area of about 2 m2. Three water flows (0.5 (Q0.5), 0.25 (Q0.25) and 0.1 L/min (Q0.1)) were applied. The turbidity was measured at the outlet of the PI at different time intervals. Obtained results show that: i) the most effective deferrization treatment corresponds to the water flow Q0.1, reducing the turbidity from 12.5 ± 3.5 (before treatment) to 0.40 ± 0.23 NTU (after treatment) for a water flow time followed at the outlet of the IP of 5.5 days, and ii) the water thus deferrized keeps its turbidity at a very satisfactory level 0.23 NTU after one year of storage at 6 °C. In view of their importance, we recommend gradually adapting these results to SADEF, while ensuring the physicochemical and microbiological quality of the water, from the source to the consumer.