WITHDRAWN: Nutrient removal effectivity of seaweeds as biofilter and water pollution control in hybrid grouper aquaculture wastewater at low salinity

Abstract

This research aims to determine the performance and nutrient removal effectivity of seaweeds species, namely Ulva fasciata., Sargassum illicifolium, Gelidium sp., and Dictyota sp. as a biofilter in hybrid grouper aquaculture wastewater at low salinity (14-17 ppt). This study used a Completely Randomized Design with 3 replications. The statistical analysis was carried out by Analysis of Variance continued with the Least Significance Difference test, and the Kruskal-Walis test with the Mann-Whitney analysis, and T-test with a confidence level of 95%. The concentrations of ammonia, nitrate, phosphate, and water quality parameters were observed every 4 days. The seaweeds uptake of N and P in water, and Specific Growth Rate were also observed. The results showed that U. fasciata was able to reduce ammonia by 75.95% and nitrate by 79.53%, which were the highest compared to other treatments, while Dictyota sp. was able to reduce the highest phosphate by 87.5% for 20 days. The highest SGR was achieved by U. fasciata at 1.91 %day-1. The highest N content uptake by seaweeds was 104.4%, and the total P of 182.3% occurred in U. fasciata. Overall, U. fasciata has the highest performance and effectiveness as a biofilter that is able to reduce nutrient waste in low-salinity from grouper aquaculture, for re-circulation or before being discharged into the environment to reduce eutrophication and harmful Algal Blooms (HABs) in aquatic environment. The highest growth rate of U. fasciata can be used as food with highly nutritional and economical value.