Phosphate Fixing Capacity Of Soil Blended With Wastewater

Abstract

The liquid waste discharged from Jimma University Dining Hall contain high amount of phosphate. Based on laboratory experimental result had indicated 10.2 mg/L phosphate concentration. The problem causes a damage aquatic environment, eutrophication and severe disturbance on the downstream community. Phosphorus is an essential plant nutrient and its deficiency limits plant growth. Phosphorus had extracted from wastewater, each treatment combination to determine the amount of Phosphorus fixed. Phosphorus recovered increased with added Phosphorus. The Laterite soil of Serbo area is deficient in available phosphorus, which results in low agricultural productivity. Therefore, it is highly needed to monitor the Phosphorus fixing capacity of these soils. The transformation of applied Phosphorus in soils was examined after treatments with different Phosphorus rates (20, 60 and 180 mg/L) and incubation periods (1, 3, 7, 14 and 28 days) under laboratory conditions. Phosphorus fixing capacity increased with depth throughout the incubation period. The apparatus used to measure phosphorus fixation was Spectrophotometer, and the experimental result showed that Laterite soil was high Fixing capacity. Phosphorus fixed varying between 56-97%. More than 90% of added P had fixed after 28-day incubation. This therefore, reduces the threat of eutrophication. Phosphorus fixed correlated positively with clay and pH, and negatively with organic carbon and available P. Clay had a significant (p < 0.05) positive correlation with pH values. Clay and pH could therefore be responsible for phosphorus fixation.