mainly causes eutrophi cation in fresh/coastal waters (Luo et al.,
2002). The actual nutrient concentration inswine wastewater is
highly dependent upon aparticular operation ofmanure collection,
housing, and/or humidity.For instance,there isaconsiderable loss
of nitrogen toair,apotential run-off,orleaching into ground water
when manure is exposed toanopen lot (Zhang and Felmann, 1997 ).