Applicability of Brown Seaweed Species (Sargassum crassifolium) for Treating Lobster Farm Wastewater
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Date
2021
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Publisher
Uva Wellassa University of Sri Lanka
Abstract
Wastewater generation in aquaculture farms, including all lobster culture practices is a serious
issue in the industry. The present study was carried out at lobster farm located at Northern Province
in Sri Lanka. Approximately 756,000 L of wastewater is generated on this farm annually and
discharges wastewater without proper treatment to the natural environment. The wastewater
discharged from lobster farm consists of organic and inorganic chemical components that can be
caused potential environmental problems. Present study focused to investigate applicability of
Brown seaweed Sargassum crassifolium biomass to efficient removal of nutrients (nitrogen and
phosphorous) from the lobster farm wastewater. The Sargassum crassifolium is an abundant
species in Northern Province, Sri Lanka. Seaweed biomass optimization was performed using three
different seaweed biomasses, viz 20 g, 30 g and 40 g and 20 g (1 g L-1) identified as the efficient
seaweed biomass. Wastewater initial physicochemical parameters pH (7.9 ± 0.02), Temperature
(29 ± 0.04 ⁰ C), Salinity (36 ± 0.03 ppt), Dissolved Oxygen (3.58 ± 0.02 mg L-1), Biological
Oxygen Demand (115 ± 0.05 mg L-1), Ammonia (1.37 ± 0.01mg L-1), Nitrite (0.143 ± 0.00 mgL-1),
Nitrate (0.243 ± 0.01 mg L-1) and Phosphate (4.760 ± 0.02 mg L-1) were analyzed using the
standard methods. Then wastewaters were collected from the farm and transferred to six glass
tanks of 50 L capacity each. The seaweed was used at 1 g L-1 density in each tank except in the
control tank. Complete randomized design was used to the experiment. Three replicates were used.
Ammonia, Nitrite, Nitrate and Phosphate were analyzed once in three days from beginning to the
end of the treatment period (28 days) to investigate the initial wastewater qualities and quality
changes after Phycoremidiation. After phycoremidiation physiochemical parameters pH (7.4 ±
0.06), Temperature (29 ± 0.03 ⁰ C), Salinity (36 ± 0.05 ppt), Dissolved Oxygen (5.74 ± 0.04 mg L-
1), Biological Oxygen Demand (95 ± 0.03 mg L-1) were analyzed in wastewater. Sargassum
crassifolium removed 1.19 ± 0.34 mg L-1 of Ammonia, 0.12 ± 0.03 mg L-1 of Nitrite, 0.14 ± 0.04
mg L-1 of Nitrate and 2.40 ± 0.72 mg L-1 of Phosphate. Nutrient removal amounts were
significantly differed (P<0.05) between control and treatment tank. The weight gains Sargassum
crassifolium during the study period was of 8.7 g thus, the seaweed has been utilized the nutrients
present in the discharged waste waters. The results of the study concluded that the nitrogen and
phosphorus in the lobster farm waste waters, can be effectively removed through Sargassum
crassifolium.
Keywords: Lobster, Sargassum crassifolium, Seaweed, Phycoremidiation
Description
Keywords
Aquaculture and Fisheries, Fish, Fisheries Industry, Wastewater, Animal Sciences