In the past decades, the application of wastewater stabilization
pond (WSP) has attracted attentions for swine effluent treatment
in many countries (Mergaert et al., 1992; Seghezzo et al., 1998).
Kiran et al. (1991) tested Eichhornia crassipes, Pistia stratiotes,
Salvinia rotundifolia and Lemna minor and found that water
hyacinth (E. crassipes) had a distinctively greater capacity of nitrogen
and phosphorus removal during summer and rainy seasons.
Both laboratory and field studies have also demonstrated that
water hyacinth plants are able to reduce the concentrations of a
variety of pollutants in swine wastewater. However, the plant cannot survive concentrated
effluents. Directly discharged waste from
swine farms in China is commonly found to be highly concentrated.
Therefore, farm operators are hesitant to use the water hyacinth
WSP treatment method. Their reluctance also is a result of
the increasingly limited land availability as well as the difficulty
in water hyacinth application