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.
