Water Quality Assessment of a Trout Farming Effluent, Bocaina, Brazil

Abstract

The concern in mitigating the negative impact generated by the discharge of nutrients in the receiving water body is a challenge for the sustainable development of Brazilian fish farms. Thus, the purpose of this study was to evaluate the water quality and environmental impact caused by trout farming system effluent with focus on discharge of phosphorus. Sampling was performed on a weekly basis in triplicate from September to November 2010. Sample sites were distributed according to the water flow: upstream from trout farming system, water supply, effluent, artificial wetland, mixing zone and downstream (60 m from effluent). In the field, pH, conductivity, dissolved oxygen, water temperature and turbidity were measured. In laboratory, nitrogen and phosphorus series, chlorophyll a, total solids suspended and their organic and inorganic fractions were analyzed. For the good growth of trout in production system, the abiotic factors described in the water quality monitoring demonstrated acceptable values. Environmentally, after passing through the production system and artificial wetland, there was an increase in concentrations of total phosphorus, total nitrogen, orthophosphate, ammonium, chlorophyll a, total solids suspended and their organic and inorganic fractions (P < 0.05). These results are related with the quality of feed, feeding management and the inefficiency of the artificial wetland. Therefore, it is necessary to use best quality feed to meet the nutritional requirements of trout, maintaining an optimal feed conversion and reducing pollution generated by effluent.

Full Water Quality Monitoring of a Traditional Flow-Through Rainbow Trout Farm

“…Furthermore, fish farming activity generates dissolved and solid wastes such as nutrients (nitrogen and phosphorus) and organic matter from fish excreta and uneaten feed. Therefore, if the effluent is discharged untreated, it could potentially impact the discharge water quality compared to make-up water, and as a consequence impact the receiving water quality [9][10][11][12][13][14].…”

Daily mass balance of phosphorus and nitrogen in effluents of production sectors of trout farming system

“…Mass balances in fish farming reported in the literature has shown high degree of nutrient discharge into the natural environment that can cause major impacts in oligotrophic systems (Bartoli et al, 2007;Araújo-Silva et al, 2014;Caramel et al, 2014). This methodology has recently been applied in Brazilian aquaculture (Araújo-Silva et al, 2014;.…”

“…This methodology has recently been applied in Brazilian aquaculture (Araújo-Silva et al, 2014;. Regarding trout farming, few studies have used the mass balance as environmental indicator (Caramel et al, 2014), especially when considering each fish development. The most studies of fingerling, juvenile and adult trout focuses on the areas of hematology, nutrition and growth (Karabulut et al, 2010;Tahmasebi-Kohyani et al, 2011).…”

Environmental indicators in effluent assessment of rainbow trout (Oncorhynchus mykiss) reared in raceway system through phosphorus and nitrogen

“…Among the different ways to improve this treatment system must consider its proportional scale to the production area and the residence time of the water (Caramel et al, 2014).…”

“…A = Representation of the organized trout farming system in three sectors: fingerlings, juveniles and adults; B = Schematic drawing of the trout farming system located in the Serra da Bocaina (SP), where: S1 = upstream production system; S2 = affluent; S3 = effluent; S4 = outlet after passing by the wetland; S5 = mixing zone; S6 = in the receiving water body (stream), 60 meters away from the effluent. Adapted from Caramel et al (2014). where N B = converted nutrient in fish biomass (kg of P or N), P = fish production (kg), DM = amount of dry matter by kilogram of fish (kg), N DM = amount of nutrient (P or N) by kilogram of dry matter of fish (kg).…”