Abstract: Among the environmental concerns of shrimp aquaculture is pollution from pond effluent. Water
hyacinth was found to be effective in treating different types of wastewater. Therefore, in this study the
potential of short term treatment of pond effluent was investigated. Wastewater from newly harvested shrimp
pond was placed in fiberglass tanks outdoor where water surface was fully-cover (F), half-cover (H) and not
covered (control) (C) with water hyacinth for 76 hours. Results show that percent reductions were in decreasing
order of F>H>C in all the parameters studied. Ammonia nitrogen in F decreased from 1.8 mg/L to 0.2 mg/L in 46
hours whereas in H and C, their concentrations were above 0.6 mg/L. For F treatment, percentage reductions
ranged from 52.5 to 100% and were in the order of NO -N>NO -N>3 2 TP>TAN>TN>TSS>RP>BOD5>COD. In H,
reduction ranged between 45.4 to 95.2% and in C they ranged from -18.5% to 74.9%. First order decay coefficient
for all the parameters were the highest in F followed by H and C treatments. This study showed that even
though the duration of the treatment was short, suspended solids, oxygen demand, nitrogen and phosphorus
reductions were significantly higher in the water hyacinth treatments compared to treatment without water
hyacinth.