Treatment and Disposal of Sugarbeet Processing Waste Water by Irrigation

Irrigation with sugarbeet processing waste water was studied at three locations for 2 or 3 years where perennial grass and alfalfa were irrigated by flooding specially graded fields. Experimental sites were scheduled for irrigation at intervals of 1, 2, or 4 weeks. This schedule was maintained for the first year until the weekly irrigated plots were discontinued because of excessive loading. Waste water was sampled twice weekly from the sugar factories, and water samples were extracted from the soil at depths of from 15 to 150 cm each time the fields were irrigated. All water samples were analyzed for chemical oxygen demand, total nitrogen, phosphorus, potassium, electrical conductivity, calcium, magnesium, sodium, sodium absorption ratio, pH, chlorine, sulfate, and bicarbonate. Soil and plants were also analyzed for selected constituents. N applications to the experimental plots ranged from 280 to 4200 kg/ha and, on the fields, from 277 to 1425 kg/ha. P applications ranged from 5 to 50 kg/ha on the experimental plots and from 11 to 43 kg/ha on the fields. K applications ranged from 195 to 6350 kg/ha on the experimental plots and from 490 to 3410 kg/ha on the fields. Water applications ranged from 28 to 201 cm/year, and COD applications ranged from 8 to 140 metric tons/ha. COD reduction in the waste water at Twin Falls averaged 48 percent in winter and 98 percent in summer; at Rupert, it averaged 84 percent in winter and 98 percent in summer; and at Nampa, it averaged 75 percent in winter and 88 percent in summer. Nitrates found in water samples extracted from 150 cm in the soil were mostly below 10 parts per million N with a few samples higher. Irrigation with sugarbeet processing waste water works well in the field