EVALUATION OF CULTIVATED LAND REQUIRED FOR TERTIARY TREATMENT OF SECONDARY EFFLUENT FROM THE EAST WWTP OF TIZI-OUZOU (ALGERIA)
Published: 28 May 2015
Abstract: Our study focuses on the physical chemical and biological effluent characterization and evaluation of cultivated soil surfaces (viticulture and citrus) for tertiary treatment of nitrogen, phosphorus and potassium content in the secondary effluent of the sewage treatment station (STEP) east of the city of Tizi-Ouzou Algeria. The results of physicochemical analyzes, performed over a period of three years, show that the treated effluent, has a slightly alkalinity (pH = 7.52), annual average concentrations of 20.15 mg/l total nitrogen from 11.30 mg/l total phosphorus and 19.35mg/l of total potassium. The determination of the parameters measured pollution indicators gives average: BOD5 = 28.32 mg/l, COD = 44.50 mg/l, MES = 14.20 mg/l. The concentrations of heavy metals in sludge from these waters are: Cr = 74.2 mg kg DM, Cu = 115 mg/Kg DM, Ni = 10.5 mg/kg DM, Pb = 6.8 mg/Kg DM and Zn = 400 mg/kg DM. They are lower than the accepted standards in the agricultural use of these effluents. The concentrations of nitrogen, phosphorus and potassium in the sludge are 11.75 g/kg DM, 8.18 g/kg DM respectively, and 16.06 g/Kg DM g/kg DM. The results of the laboratory tests also show the total absence of parasites or their eggs may limit agricultural reuse of the effluent. The area planted for tertiary treatment obtained experimentally for vineyards and citrus cultivation, applied to the treated effluent of the STEP East Tizi-Ouzou with a capacity of 120,000 population equivalents are measured at 909 ha to 983 ha. The nitrogen inputs, phosphorus and potassium in the annual volume of irrigation are respectively 148.20 kg / ha / year, 81.69 kg / ha / year and 139.88 kg/ha / year for viticulture and 134 58 kg / ha / year, 75.47 kg / ha / year and 129.24 kg / ha / year for citrus. The respective averages nutrient equivalent inhabitants by hectare by year are respectively 132 EH / ha / year and 122 EH/ha / year for viticulture and citrus. The annual flows of 132.385 tonnes of total nitrogen, total phosphorus 74.241 tons and 127.129 tons of potassium with a year cumulation from 6 570 000 m3 of water.
Keywords: treated wastes, nutriments, valorization, filter, agrumiculture, viticulture
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