Performance of Azolla caroliniana Willd. and Salvinia auriculata Aubl. on fish farming effluent

Toledo, José Júlio de; Penha, Jerry

doi:10.1590/s1519-69842011000100007

Cited by 12 publications

(9 citation statements)

References 31 publications

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“…Nevertheless, a substantial minority of respondents would prefer supporting subsistence fishers by helping them to adopt fish farming techniques. Some have argued that this would be a desirable strategy for growing the economy and reducing pressure on river fish stocks (Cavalett et al 2007;Déo Dias et al 2012;Saint-Paul 2017), despite some potentially negative implications for water quality (Toledo and Penha 2011). This strategy would also maximise hydroelectric power production from rivers, which could be used for industrial applications and economic development.…”

Section: Implications and Conclusionmentioning

confidence: 99%

“…Several strategies have been proposed locally, which overlap with some of the recommendations for the management of dam construction impacts made by scientists globally (Tagliaferro et al 2013;Tundisi et al 2014), giving relevance to our case study beyond the particular local context. One strategy currently gaining traction in the river basin is the introduction of fish farming (Alho 2008;Toledo and Penha 2011), which reduces the dependency on increasingly scarce river fish stocks, and may also lead to growth in the formal economy (Cavalett et al 2007;Déo Dias et al 2012;Saint-Paul 2017). Fish farming is already carried out in many places elsewhere around the globe where dams have interrupted routes of migratory fish (see e.g.…”

Section: Introductionmentioning

confidence: 99%

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Understanding Public Views on a Dam Construction Boom: the Role of Values

Schulz

Martín-Ortega

Glenk

2019

Water Resour Manage

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Large numbers of dams for hydroelectric power production are currently planned or under construction in many areas around the world. While positive and negative social and environmental impacts of dams are increasingly well understood, little is known about attitudes of the general public towards dams, even though benefits to wider society are often cited to legitimise their construction. In Brazil's Upper Paraguay River Basin, more than 100 mostly small-scale hydropower dams are planned or under construction in what can be considered a regional dam construction boom. Here we analyse public preferences for strategies to manage dam impacts in the area by investigating the value base that underpins such preferences, drawing on the recently proposed Value Landscapes Approach as our theoretical framework and data from a large representative household survey (N = 1067). We find that contrasting attitudes towards dams, expressed in preferences for economically or ecologically oriented water policies are informed by opposing underlying value landscapes, that is, groups of closely related fundamental, governance-related, and assigned (water) values. While such tensions between opposing values can never be fully eliminated, our research nevertheless gives insights to policy-makers seeking to minimise value conflict and to improve the political legitimacy of public decision-making on dam construction. Moreover, we find that a majority of members of the general public would prefer concentrating dam construction on some rivers while keeping others free-flowing, with direct implications for ecosystems and inland fisheries. This finding may guide policy-makers wishing to develop publicly supported water resources management strategies.

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Section: Implications and Conclusionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Understanding Public Views on a Dam Construction Boom: the Role of Values

Schulz

Martín-Ortega

Glenk

2019

Water Resour Manage

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“…enhances its nutrition value [ 38 ]. Moreover, it can be used as a biological filter for purifying water as well as providing food and shelter to fish and invertebrates [ 39 ].…”

Section: Introductionmentioning

confidence: 99%

Physiological Behavior of the Aquatic Plant Azolla sp. in Response to Organic and Inorganic Fertilizers

Azab

Soror

2020

Plants

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The present investigation aims to evaluate the impacts of organic and inorganic fertilizers on the water parameters and physiological behaviors of an aquatic plant (Azolla sp.). The experiment used three groups: treatment with organic or inorganic fertilizer and a group with no fertilization as a control. Azolla sp. were grown in cement ponds that received different treatments. For water analysis, the obtained results clarified that fertilization resulted in no variation in the temperature or total hardness among different treatments. Organic fertilizer increased the dissolved phosphorus content, total hardness, and bicarbonate alkalinity, as well as the total phosphorus content, whereas inorganic treatment increased the pH, total ammonia content, and total nitrogen content. Regarding the biochemical composition of Azolla sp., the chlorophyll content showed no variation among different treatment groups, while organic matter showed high variation among different treatment groups. The highest values for ash and fat content were recorded in control ponds. The highest protein content was found in organic treatment ponds. The addition of fertilizers led to an increase in the tissue contents of N and P compared to the control. This increase was highest when Azolla sp. was fertilized with organic fertilizer. The atomic N:P ratio was low in tissues subjected to either treatment compared with the control. The doubling time of Azolla sp. was decreased by fertilization. It is concluded that different fertilizer systems have significant effect on physico-chemical and biological parameters of water. Fertilization positively affects Azolla sp. growth. Organic fertilizer was more efficient for the growth of Azolla sp., so it can be considered as a source of biofertilizer and green manure in areas where it spreads.

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“…Constructed wetlands are one of the most promising methods for effluent treatment for wastewater of biodigesters and aquaculture, mainly in Brazil (Henry-Silva and Camargo, 2008;Sipaúba-Tavares and Braga, 2008;Toledo and Penha, 2011). The system is based on physical, chemical and biological processes and may deal with a great variability of pollutant load characterized by high concentration and great water flow (Brix et al, 2007;Sindilariu et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Efficiency of a constructed wetland for wastewaters treatment

Travaini-Lima

Sipaúba-Tavares

2012

Acta Limnol. Bras.

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Aim: The limnological characteristics of three different inlets water of the constructed wetland were compared in terms of concentration data and loading rate data and evaluated the removal efficiencies of nutrients, solids, BOD 5 , chlorophyll-a and thermotolerant coliforms (TC) by the treatment system; Methods: The constructed wetland, measuring 82.8 m 2 and with detention time of 1 hour and 58 minutes in the rainy season and 2 hours and 42 minutes in the dry one, was provided with four species, Cyperus giganteus Vahl, Typha domingensis Pers., Pontederia cordata L. e Eichhornia crassipes (Mart.) Solms. The sampling sites evaluated in the dry (D) and rainy (R) seasons were: inlet water from aquaculture farm = IA; inlet channel of rainwater runoff = IR; inlet from UASB wastewater = IB; outlet wetland = OUT. The conductivity, pH, temperature, dissolved oxygen, alkalinity, BOD 5 , total soluble and dissolved solids, nitrogen, phosphorus, chlorophyll-a and TC were analyzed. Multivariate analyses, such as Cluster and Principal Components Analysis (PCA), were carried out to group sampling sites with similar limnological characteristics; Results: In the PCA with the concentration data was retained 90.52% variability of data, correlating the inlet IB with high concentrations of conductivity, alkalinity, pH, TC, nutrients and solids. Regarding loading rate data, the PCA was retained 80.9% of the data's total variability and correlated the sampling sites IA D, IA R and OUT R with higher BOD 5 , chlorophyll-a, TDS, nitrate, nitrite, total-P, temperature, oxygen and water flow. The highest removal efficiencies rates occurred in the dry season, mainly in concentration, with 78% of ammonia, 95.5% of SRP, 94.9% of TSS and 99.9% of TC; Conclusions: The wetland was highly efficacious in the removal of nutrients, solids, BOD 5 , chlorophyll-a and TC, mainly during the dry season. The system restructuring to increase the detention time during the rainy season and a pre-treatment of UASB wastewater, can increase the retention of nutrients and solids by wetland.

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Performance of Azolla caroliniana Willd. and Salvinia auriculata Aubl. on fish farming effluent

Cited by 12 publications

References 31 publications

Understanding Public Views on a Dam Construction Boom: the Role of Values

Understanding Public Views on a Dam Construction Boom: the Role of Values

Physiological Behavior of the Aquatic Plant Azolla sp. in Response to Organic and Inorganic Fertilizers

Efficiency of a constructed wetland for wastewaters treatment

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