wAbstract
@Long-term applications of animal manures to agricultural fields
have caused serious environmental concerns over release of excessive
nutrients, heavy metals, and fecal coliforms into waterbodies.
An alternative is to control nutrient bioavailability of animal
manures before their land application. In this study, two types
of bauxite residues (red mud and brown mud) were evaluated for
their potential use in reducing leachability of phosphorus (P),
copper (Cu), and zinc (Zn) as well as fecal coliform and NH3 release from animal manures. Poultry litter
and cattle manures collected from production farms were mixed
with bauxite residues at mixing rates of 11“, 22“, and 50“. Bauxite
residues were effective in suppressing the leaching of water-soluble
P, As, Cu, and Zn from animal manures. At 22“ mixing rate, brown
mud reduced water-extractable P by 40“ and 70“ from chicken litter
and cattle manure, whereas red mud reduced water-extractable P
by 27“ and 55“, respectively, in five successive extractions.
Amending manure with bauxite residues also decreased populations
of fecal coliform. Bauxite residues did not increase NH3
release despite its relatively high pH. The results suggest that
bauxite residues could be used as a potential amendment for reducing
P and other contaminant leaching in animal manures and improve
the application of both wastes for beneficial use.
Keywords: Bauxite residue; Animal manure; Water-extractable phosphorus;
Zinc; Copper; Fecal coliformx
1. Introduction
2. Materials and methods
@2.1. Animal waste and bauxite residue
@2.2. Phosphorus sorption
@2.3. Successive extraction experiment
@2.4. Incubation for fecal coliform
@2.5. Ammonia volatilization
@2.6. Statistical analysis
3. Results and discussion
@3.1. Characteristics of animal waste and bauxite residues
@3.2. Bauxite residue amendment impact on water-soluble P, Zn,
Cu, and As
@3.3. Impact on fecal coliform and ammonia release
4. Conclusions
References