The document discusses using the carbon to nitrogen (C:N) ratio to control inorganic nitrogen levels in aquaculture systems. Adding carbohydrates feeds bacteria which use the carbon for energy and growth, immobilizing nitrogen in microbial proteins. Lowering the C:N ratio in feed by adding carbohydrates or reducing protein can reduce ammonium levels. Experimental results showed that adding glucose reduced ammonium in shrimp tanks and tilapia ponds by feeding bacteria. Microbial proteins produced were a nutrient source for the fish. Precise data is still needed to optimize feed composition for different aquaculture systems.
This document provides a literature review on using microalgae for wastewater treatment. It discusses that microalgae can effectively remove nutrients from wastewater through assimilation and other phenomena like ammonia volatilization and phosphorus precipitation caused by pH increase. Domestic wastewater contains all the necessary nutrients for good algal growth, with light being the main limiting factor, especially at higher latitudes. Key factors for successful wastewater treatment with microalgae include depth, turbulence, and hydraulic retention time to ensure good mixing and light exposure for the algae.
Assessment of aquaculture sediment for agricultural fertilizer supplement and...researchagriculture
Overuse of farmlands for crop production and rising cost of chemical Overuse of farmlands for crop production and rising cost of chemical fertilizers have grossly affected crop yield, production and food availability, and the search for alternative use of locally available aquaculture-waste for fertilizer and soil improvement can improve crop yield and food availability for the teaming population of Nigeria and other sub-Saharan African countries. This research determined the pH, Organic Matter, nitrate and phosphate qualities of 10 fishpond sediments for use as agricultural fertilizer supplement and soil conditioner in Owerri, Nigeria. Samples were subjected to standard physicochemical analysis. The pH ranged from 8.1-7.3, organic matter from 46.6-61.3 g/kg, nitrate from 2.6-3.2 g/kg and phosphate from 0.05-0.1 g/kg. The higher the organic matter in the sediment samples, the higher the recorded pH, nitrate and phosphate from the different ponds sediments. Organic material, nitrate, phosphate and pH variation in the sediments might be due to nutrients added to pond water from fertilizer, unconsumed feed, fish feaces and metabolites. The nitrate and phosphate are major plant nutrients; organic matter can be used as soil conditioner. The pH can determine the soil chemistry and availability of the nutrients. The fish pond sediment can help to improve soil texture and soil fertility, which may influence soil aeration, water, and nutrient-holding capacity and root penetration by crops and increased crops growth and yield. It can serve as alternative uses for fertilizer, soil conditioner, and its application as a waste management approach in aquaculture for environmental sustainability.
Article Citation:
Ihejirika CE, Onwudike SU, Nwaogu LA, Emereibeole EI, Ebe TE and Ejiogu CC.
Assessment of aquaculture sediment for agricultural fertilizer supplement and soil conditioner in Owerri Urban, Nigeria.
Journal of Research in Agriculture (2012) 1(1): 034-038.
Full Text:
http://www.jagri.info/documents/AG0009.pdf
Assessment of aquaculture sediment for agricultural fertilizer supplement an...researchagriculture
Overuse of farmlands for crop production and rising cost of chemical
Overuse of farmlands for crop production and rising cost of chemical fertilizers have
grossly affected crop yield, production and food availability, and the search for
alternative use of locally available aquaculture
-
waste for fertilizer and soil
improvement can improve crop yield and food availability for the teaming population
of Nigeria and other sub
-
Saharan African countries. This research determined the pH,
Organic Matter, nitrate and phosphate qualities of 10 fishpond sediments for use as
agricultural fertilizer supplement and soil conditioner in Owerri, Nigeria. Samples
were subjected to standard physicochemical analysis. The pH ranged from 8.1
-
7.3,
organic matter from 46.6
-
61.3 g/kg, nitrate from 2.6
-
3.2 g/kg and phosphate from
0.05
-
0.1 g/kg. The higher the organic matter in the sediment samples, the higher the
recorded pH, nitrate and phosphate from the different ponds sediments. Organic
material, nitrate, phosphate and pH variation in the sediments might be due to
nutrients added to pond water from fertilizer, unconsumed feed, fish feaces and
metabolites. The nitrate and phosphate are major plant nutrients; organic matter can
be used as soil conditioner. The pH can determine the soil chemistry and availability
of the nutrients. The fish pond sediment can help to improve soil texture and soil
fertility, which may influence soil aeration, water, and nutrient
-
holding capacity and
root penetration by crops and increased crops growth and yield. It can serve as
alternative uses for fertilizer, soil conditioner, and its application as a waste
management approach in aquaculture for environmental sustainability.
The document discusses anaerobic digestion monitoring at a plant in Mafra, Portugal under high ammonia concentrations. Key findings include:
- The plant achieves an average biogas productivity of 600 Nm3/t VS at a loading rate of 7.2 t VS/m3.d, with waste feeding TS averaging 50% VS.
- Ammonia nitrogen levels up to 4±1g/L did not inhibit methanogens due to the mesophilic operating temperature and pH.
- The liquid effluent has a soluble COD of 25g/L including 2-4g/L of VFA and 2-4g/L of ammonia nitrogen, and is sent to an
The document discusses biorenewable gaseous fuels, focusing on biogas produced through anaerobic digestion. It describes the multi-step anaerobic digestion process where organic materials are broken down by microorganisms into methane and carbon dioxide biogas. Key points include: Anaerobic digestion is well established and involves hydrolysis of materials into sugars and acids, followed by acetogenesis and methanogenesis to produce biogas. Biogas can be processed and used as an energy source, though it also contains impurities. Maintaining proper temperature, pH and nutrient levels is important for optimal microbial activity in anaerobic digestion.
The document discusses various ways that sewage sludge can be converted into biofuels through biological processes. It describes how biodiesel, biogas, and bioethanol can be produced from sewage sludge lipids and biomass. For biodiesel, lipids in sewage sludge are extracted and converted to fatty acid methyl esters through transesterification. Biogas is produced via anaerobic digestion of sewage sludge, yielding a methane-rich gas. Bioethanol is generated by fermenting sewage sludge and distilling the resulting alcohol. Overall, the document outlines the biological pathways for transforming sewage sludge into several types of renewable biofuels.
This review article summarizes approaches for managing food waste through anaerobic digestion to produce energy and recycle nutrients. Anaerobic digestion is a multi-step process where microorganisms break down biodegradable material in the absence of oxygen and produce methane gas and digestate. Food waste is a suitable substrate for anaerobic digestion due to its biodegradable composition. The article reviews studies on producing methane from food waste via anaerobic digestion and discusses the microbial populations involved in the digestion process and factors that affect efficiency.
Marine algae are a rich source of natural bioactive compounds with pharmaceutical, nutraceutical and cosmetic applications. Multi-omics approaches can be used to identify compounds of interest from algae. Notable compounds isolated from algae include carotenoids, fatty acids, antibiotics, and biosurfactants. Algae also have applications as human and animal food, in space research producing oxygen, and in energy production through biofuel and methane. Microalgae can be used to remediate wastewater by removing nutrients and excess carbon dioxide.
This document provides a literature review on using microalgae for wastewater treatment. It discusses that microalgae can effectively remove nutrients from wastewater through assimilation and other phenomena like ammonia volatilization and phosphorus precipitation caused by pH increase. Domestic wastewater contains all the necessary nutrients for good algal growth, with light being the main limiting factor, especially at higher latitudes. Key factors for successful wastewater treatment with microalgae include depth, turbulence, and hydraulic retention time to ensure good mixing and light exposure for the algae.
Assessment of aquaculture sediment for agricultural fertilizer supplement and...researchagriculture
Overuse of farmlands for crop production and rising cost of chemical Overuse of farmlands for crop production and rising cost of chemical fertilizers have grossly affected crop yield, production and food availability, and the search for alternative use of locally available aquaculture-waste for fertilizer and soil improvement can improve crop yield and food availability for the teaming population of Nigeria and other sub-Saharan African countries. This research determined the pH, Organic Matter, nitrate and phosphate qualities of 10 fishpond sediments for use as agricultural fertilizer supplement and soil conditioner in Owerri, Nigeria. Samples were subjected to standard physicochemical analysis. The pH ranged from 8.1-7.3, organic matter from 46.6-61.3 g/kg, nitrate from 2.6-3.2 g/kg and phosphate from 0.05-0.1 g/kg. The higher the organic matter in the sediment samples, the higher the recorded pH, nitrate and phosphate from the different ponds sediments. Organic material, nitrate, phosphate and pH variation in the sediments might be due to nutrients added to pond water from fertilizer, unconsumed feed, fish feaces and metabolites. The nitrate and phosphate are major plant nutrients; organic matter can be used as soil conditioner. The pH can determine the soil chemistry and availability of the nutrients. The fish pond sediment can help to improve soil texture and soil fertility, which may influence soil aeration, water, and nutrient-holding capacity and root penetration by crops and increased crops growth and yield. It can serve as alternative uses for fertilizer, soil conditioner, and its application as a waste management approach in aquaculture for environmental sustainability.
Article Citation:
Ihejirika CE, Onwudike SU, Nwaogu LA, Emereibeole EI, Ebe TE and Ejiogu CC.
Assessment of aquaculture sediment for agricultural fertilizer supplement and soil conditioner in Owerri Urban, Nigeria.
Journal of Research in Agriculture (2012) 1(1): 034-038.
Full Text:
http://www.jagri.info/documents/AG0009.pdf
Assessment of aquaculture sediment for agricultural fertilizer supplement an...researchagriculture
Overuse of farmlands for crop production and rising cost of chemical
Overuse of farmlands for crop production and rising cost of chemical fertilizers have
grossly affected crop yield, production and food availability, and the search for
alternative use of locally available aquaculture
-
waste for fertilizer and soil
improvement can improve crop yield and food availability for the teaming population
of Nigeria and other sub
-
Saharan African countries. This research determined the pH,
Organic Matter, nitrate and phosphate qualities of 10 fishpond sediments for use as
agricultural fertilizer supplement and soil conditioner in Owerri, Nigeria. Samples
were subjected to standard physicochemical analysis. The pH ranged from 8.1
-
7.3,
organic matter from 46.6
-
61.3 g/kg, nitrate from 2.6
-
3.2 g/kg and phosphate from
0.05
-
0.1 g/kg. The higher the organic matter in the sediment samples, the higher the
recorded pH, nitrate and phosphate from the different ponds sediments. Organic
material, nitrate, phosphate and pH variation in the sediments might be due to
nutrients added to pond water from fertilizer, unconsumed feed, fish feaces and
metabolites. The nitrate and phosphate are major plant nutrients; organic matter can
be used as soil conditioner. The pH can determine the soil chemistry and availability
of the nutrients. The fish pond sediment can help to improve soil texture and soil
fertility, which may influence soil aeration, water, and nutrient
-
holding capacity and
root penetration by crops and increased crops growth and yield. It can serve as
alternative uses for fertilizer, soil conditioner, and its application as a waste
management approach in aquaculture for environmental sustainability.
The document discusses anaerobic digestion monitoring at a plant in Mafra, Portugal under high ammonia concentrations. Key findings include:
- The plant achieves an average biogas productivity of 600 Nm3/t VS at a loading rate of 7.2 t VS/m3.d, with waste feeding TS averaging 50% VS.
- Ammonia nitrogen levels up to 4±1g/L did not inhibit methanogens due to the mesophilic operating temperature and pH.
- The liquid effluent has a soluble COD of 25g/L including 2-4g/L of VFA and 2-4g/L of ammonia nitrogen, and is sent to an
The document discusses biorenewable gaseous fuels, focusing on biogas produced through anaerobic digestion. It describes the multi-step anaerobic digestion process where organic materials are broken down by microorganisms into methane and carbon dioxide biogas. Key points include: Anaerobic digestion is well established and involves hydrolysis of materials into sugars and acids, followed by acetogenesis and methanogenesis to produce biogas. Biogas can be processed and used as an energy source, though it also contains impurities. Maintaining proper temperature, pH and nutrient levels is important for optimal microbial activity in anaerobic digestion.
The document discusses various ways that sewage sludge can be converted into biofuels through biological processes. It describes how biodiesel, biogas, and bioethanol can be produced from sewage sludge lipids and biomass. For biodiesel, lipids in sewage sludge are extracted and converted to fatty acid methyl esters through transesterification. Biogas is produced via anaerobic digestion of sewage sludge, yielding a methane-rich gas. Bioethanol is generated by fermenting sewage sludge and distilling the resulting alcohol. Overall, the document outlines the biological pathways for transforming sewage sludge into several types of renewable biofuels.
This review article summarizes approaches for managing food waste through anaerobic digestion to produce energy and recycle nutrients. Anaerobic digestion is a multi-step process where microorganisms break down biodegradable material in the absence of oxygen and produce methane gas and digestate. Food waste is a suitable substrate for anaerobic digestion due to its biodegradable composition. The article reviews studies on producing methane from food waste via anaerobic digestion and discusses the microbial populations involved in the digestion process and factors that affect efficiency.
Marine algae are a rich source of natural bioactive compounds with pharmaceutical, nutraceutical and cosmetic applications. Multi-omics approaches can be used to identify compounds of interest from algae. Notable compounds isolated from algae include carotenoids, fatty acids, antibiotics, and biosurfactants. Algae also have applications as human and animal food, in space research producing oxygen, and in energy production through biofuel and methane. Microalgae can be used to remediate wastewater by removing nutrients and excess carbon dioxide.
This document summarizes biological processes for converting carbon dioxide and hydrogen into liquid fuels and chemicals. It discusses several microorganisms and pathways being developed for this purpose, known as "electrofuels". These include Ralstonia eutropha and Clostridium ljungdahlii, which can fix carbon dioxide via the Calvin-Benson-Bassham cycle or Wood-Ljungdahl pathway respectively. The document also reviews computational analyses of carbon fixation pathways and their relative energetic costs for producing biomass and fuels.
This document summarizes a study that evaluated the effectiveness of different polylactate compounds for stimulating microbial reduction of hexavalent chromium (CrVI) in groundwater. Microcosm experiments were conducted using Hanford site sediments and groundwater amended with various polylactate compounds and CrVI. Results showed that the polylactate compounds stimulated greater microbial biomass and activity compared to sodium lactate. CrVI reduction occurred via both direct enzymatic mechanisms and indirect microbial production of reductants like hydrogen. Analysis of the microbial communities revealed enrichments of Pseudomonas and sulfate-reducing Desulfosporosinus species that correlated with CrVI reduction and geochemical changes. Overall, the polylactate compounds
Coral Reef Biomineralisation effect by Ocean AcidificationRoneet Ghosh
The document summarizes a study that investigated the physiological and cellular impacts of ocean acidification on the reef-building coral Acropora millepora. The key findings are:
1) Exposure to high CO2 conditions predicted for the future caused widespread changes in gene expression in A. millepora related to metabolism, membrane-cytoskeleton interactions, signaling, and other processes.
2) Physiologically, corals exposed to high CO2 lost over half their symbiotic algae (Symbiodinium) populations and had decreased photosynthesis and respiration rates.
3) While calcification was not observed to decrease over the 28-day study, the cellular and physiological changes observed
Wan Marlin Rohalin, Nadzifah Yaakub and Najwa Mohd Fazdil. “Level of Zinc and Lead in Freshwater Fishes in Balok River, Pahang, Malaysia” United International Journal for Research & Technology (UIJRT) 1.1 (2019): 44-48.
Risk analysis the content of mercury (hg) in a water environmentTanty Puspa Sari
Terpaparrnya suatu zat dalam lingkungan sekarang ini dapat terjadi diberbagai jenis lingkungan. Salah satu zat yang dapat terpapar dalam suatu lingkungan adalah Hg atau biasa disebut merkuri. Merkuri merupakan unsur yang sangat jarang dalam kerak bumi, dan relatif terkonsentrasi pada beberapa daerah vulkanik dan endapan-endapan mineral biji dari logam-logam berat. Merkuri banyak terdapat di lingkungan terutama perairan.
Adapun cara penelitian yang digunakan adalah cross sectional, yaitu penelitian untuk mempelajari dinamika korelasi antara faktor-faktor resiko dengan efek, dengan cara pendekatan pengumpulan data atau studi literature. Adapun hasil penelitian kondisi air sungai di wilayah pertambangan Cisoka pada tahun 2005 (< 0,05 x 10-3 ppm Hg), berada di bawah baku mutu air menurut Peraturan Pemerintah No. 82 Tahun 2001 (< 0,001 ppm), sedangkan pada tahun 2011, kadar Hg rata-rata berada di atas baku mutu air yaitu 0,00392 ppm. Akibat banyaknya merkuri yang terdapat di lingkungan dapat mengakibatkan air berubah menjadi warna keruh dan tercemar. Adapun Solusi untuk mengurangi merkuri di perairan yaitu dengan Penanggulangan (pengendalian dan pencegahan) dampak pencemaran dilakukan dengan penataan kembali tata ruang
A bio refinery is a facility that converts biomass into multiple fuels, power, chemicals, and products. This report evaluates the feasibility of a bio refinery approach using algae. It discusses using algae grown in wastewater to produce electricity, biodiesel, biogas, and bioethanol. The bio refinery concept aims to reduce water usage, lower costs by using waste resources like CO2 and wastewater, and produce multiple revenue streams from algal biomass. While high upfront costs and concerns over algal toxins remain challenges, the report finds the bio refinery approach could provide sustainable fuel production and wastewater treatment.
E. coli O157:H7 was able to survive in irrigation water under varying physico-chemical conditions. It exhibited the highest survival at 1% NaCl but survival decreased with increasing NaCl concentration. pH 4 decreased survival over time while pH 9 allowed moderate survival. Iron enhanced survival in a concentration-dependent manner. Nitrate supported growth at 10 mg/L. Combinations of 5% NaCl and pH 4 or 10 mg/L iron and pH 9 further increased survival compared to individual parameters. E. coli was also able to enter a viable but non-culturable state and form biofilms, enabling long-term survival in irrigation water.
microbiological quality of water in aquaculture.RuksanaRukku
The document discusses the importance of water quality parameters for aquaculture. It notes that inadequate water quality can cause issues for production yields, fish health, and profits. It recommends testing water sources for parameters like ammonia, iron, alkalinity, and contaminants before establishing an aquaculture facility. It also suggests treating source water through aeration, filtration, ultraviolet sterilization, and activated carbon filtration to ensure the water can sustain life. Dissolved oxygen is identified as the most important chemical parameter, as low levels can cause fish stress and mortality. Methods for measuring chemical oxygen demand, total oxygen demand, and biochemical oxygen demand are also outlined.
This document summarizes a bio-hydrogen production process from agricultural waste. The process involves using sugar beet molasses and cow manure as feedstocks in dark and photo bioreactors to produce hydrogen through fermentation. The hydrogen is then purified, liquefied, and 38,800 kg can be produced per day. The process is projected to be economically viable and reduce carbon dioxide emissions compared to current hydrogen production methods. Key constraints and areas for further research and development are identified.
This document discusses Chlorella vulgaris and Ulva lactuca as potential sources for biodiesel and bioethanol production.
C. vulgaris is a microalgae that can be grown using photosynthesis. It contains lipids that can be extracted and converted to biodiesel via a transesterification process. U. lactuca is a type of macroalgae that contains polysaccharides like cellulose that can be broken down into sugars and fermented by yeast into bioethanol. The document outlines the steps involved in cultivating and processing these algae, as well as their economic and environmental benefits.
This presentation discusses biogas production from garbage through anaerobic digestion. It defines biogas as a combustible gas produced through biological breakdown of organic matter without oxygen. The presentation outlines the four stages of anaerobic digestion: hydrolysis, acidogenesis, acetogenesis, and methanogenesis. It also discusses factors that affect biogas production such as temperature, pH, carbon/nitrogen ratio, organic loading rate, and hydraulic retention time. Applications of biogas include electricity generation, transportation fuel, and cooking fuel.
Medical Conferences, Pharma Conferences, Engineering Conferences, Science Conferences, Manufacturing Conferences, Social Science Conferences, Business Conferences, Scientific Conferences Malaysia, Thailand, Singapore, Hong Kong, Dubai, Turkey 2014 2015 2016
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GRDS is a blend of Open Access Publications and world-wide International Conferences and Academic events. The prime mission of GRDS is to make continuous efforts in transforming the lives of people around the world through education, application of research and innovative ideas.
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Heavy Metals in Sediment from Alvarado Lagoon System in Veracruz, MéxicoIJEAB
This document analyzes heavy metal concentrations in sediment samples from 41 stations in the Alvarado lagoon system in Veracruz, Mexico. Sediment samples were analyzed for levels of Pb, Cd, Cu, Cr, and Co. The highest metal concentration found was for Co at 9.53 μg/g. Most metal levels were within international limits except for Cd. While concentrations were low, the presence of heavy metals indicates potential risks to public health and warrants further continuous monitoring of sediment quality in the lagoon system.
In aquaculture, environmental impacts such as deteriorated water quality and poor pond bottoms are becoming challenging and omnipresent problems. This article highlights measures which can be taken to improve the quality of water and soil in aquaculture ponds, and therefore the immediate environment of fish and shrimp. Better rearing conditions will improve the overall performance of your fish and shrimp.
This document summarizes a study that investigated the bioaccumulation and distribution of organochlorine pesticide residues in the food web of Lagos Lagoon, Nigeria. Samples of water, sediment, plankton, benthic invertebrates, and fish were collected from four locations in the lagoon and analyzed for 18 organochlorine pesticides using gas chromatography. The highest concentrations of pesticides were found in sediment samples, with total concentrations up to 2,953.84 μg/kg. Pesticide concentrations increased higher up the food web, with the highest levels found in predatory fish species. The results indicate bioaccumulation and biomagnification of pesticides in the Lagos Lago
The document summarizes several biochemical routes for producing renewable fuels and chemicals, including anaerobic digestion, transesterification, and photofermentation. It discusses the key steps and microorganisms involved in anaerobic digestion, including hydrolysis, acidogenesis, acetogenesis, and methanogenesis. It also explains the transesterification reaction used to convert triglycerides to biodiesel and glycerin, and some of the process considerations for biodiesel production. Photofermentation is mentioned but not described.
The Contribution of Phytoplankton to the Primary Production in Floodplain Lak...Premier Publishers
This study aimed to estimate photosynthetic productivity of phytoplankton and water quality in two floodplain lakes of north Bihar, India. Gross phytoplankton productivity ranged from 1.849 g Cm-2day-1 to 4.994 g Cm-2day-1 at Tarawe chaur and 1.319 g Cm-2day-1 to 3.965 g Cm-2day-1 at Gamharia chaur. The net primary productivity measured as 1.037 g Cm-2day-1 to 3.849 g Cm-2day-1 at Tarawe chaur and 1.003 g Cm-2day-1 to 2.621 g Cm-2day-1 at Gamharia chaur. Primary productivity (GPP and NPP) of phytoplankton show a single annual peak. Respiration rates varied between 0.428 g Cm-2day-1 to 2.017 g Cm-2day-1 at Tarawe chaur and 0.489 g Cm-2day-1 to 1.475 g Cm-2day-1 at Gamharia chaur. Seasonal variation in phytoplankton gross and the net productivity was almost similar, highest in summer and lowest in winter. NPP/GPP ratio and respiration as percentage of gross production were computed. Physico-chemical parameters of water were analysed concurrently.
This document summarizes information about the enzyme urease. It discusses that urease is a nickel-containing metalloenzyme found in many organisms that catalyzes the hydrolysis of urea to produce ammonia and carbon dioxide. The active site contains two nickel ions that are bridged by ligands. Urease plays important roles in nitrogen cycling in soils and the digestive systems of ruminants and humans. Deficiencies in urease or related enzymes can cause health issues if not properly treated.
This study evaluated the effect of two methods of carbohydrate fertilization on nutrient discharge, sludge quantity and characteristics in biofloc shrimp culture. Six tanks were divided into two treatments - continuous molasses fertilization throughout cultivation (CONT) or initial molasses only in early weeks (INI). Both treatments stocked shrimp at 180 animals/m2 and cultured them for 12 weeks. The CONT treatment produced more total suspended solids (TSS) in sludge (0.25 kg/kg feed) than INI (0.16 kg/kg feed). Sludge from both treatments had high volatile solids but low carbon:nitrogen ratios and BOD:TSS ratios, indicating difficulty for anaerobic digestion treatment
This document discusses management and design considerations for producing shrimp in recirculating aquaculture systems. It outlines three main types of management regimes - chemoautotrophic, heterotrophic, and photoautotrophic - that differ in how they remove ammonia and utilize organic matter. Chemoautotrophic systems rely solely on nitrifying bacteria but do not support shrimp growth well. Heterotrophic systems use heterotrophic bacteria to remove ammonia and produce organic flocs to feed shrimp, allowing lower protein feeds. Photoautotrophic systems use algae but experience unstable swings that can stress shrimp. Design must account for the type of organic matter production and removal needed to support shrimp nutrition.
This study used Illumina sequencing of the 16S rRNA gene to analyze changes in the rumen microbiome of cattle subjected to feed restriction. The main findings were:
1) Feed restriction caused a large decrease in an abundant Succinivibrionaceae species and a significant increase in Methanobrevibacter gottschalkii.
2) Fifty-five days after being returned to a normal diet, the rumen microbiomes of previously restricted cattle were not different from controls, showing the disruption from restriction did not have long-term effects.
3) The rumen microbiome was not associated with compensatory growth in cattle 55 days after restriction ended.
1) The document summarizes research on the effect of different carbon sources on bio-floc formation in Pacific white shrimp culture.
2) It finds that Bacillus sp. bacteria were present in all treatments with added carbon sources. Molasses supported Alcaligenes, Bacillus, and Kurthia genera while tapioca supported Actinobacter and Bacillus.
3) Floc volume increased over time in all treatments until the end of the maintenance period, with tapioca and tapioca by-product treatments resulting in higher floc volumes.
This document summarizes biological processes for converting carbon dioxide and hydrogen into liquid fuels and chemicals. It discusses several microorganisms and pathways being developed for this purpose, known as "electrofuels". These include Ralstonia eutropha and Clostridium ljungdahlii, which can fix carbon dioxide via the Calvin-Benson-Bassham cycle or Wood-Ljungdahl pathway respectively. The document also reviews computational analyses of carbon fixation pathways and their relative energetic costs for producing biomass and fuels.
This document summarizes a study that evaluated the effectiveness of different polylactate compounds for stimulating microbial reduction of hexavalent chromium (CrVI) in groundwater. Microcosm experiments were conducted using Hanford site sediments and groundwater amended with various polylactate compounds and CrVI. Results showed that the polylactate compounds stimulated greater microbial biomass and activity compared to sodium lactate. CrVI reduction occurred via both direct enzymatic mechanisms and indirect microbial production of reductants like hydrogen. Analysis of the microbial communities revealed enrichments of Pseudomonas and sulfate-reducing Desulfosporosinus species that correlated with CrVI reduction and geochemical changes. Overall, the polylactate compounds
Coral Reef Biomineralisation effect by Ocean AcidificationRoneet Ghosh
The document summarizes a study that investigated the physiological and cellular impacts of ocean acidification on the reef-building coral Acropora millepora. The key findings are:
1) Exposure to high CO2 conditions predicted for the future caused widespread changes in gene expression in A. millepora related to metabolism, membrane-cytoskeleton interactions, signaling, and other processes.
2) Physiologically, corals exposed to high CO2 lost over half their symbiotic algae (Symbiodinium) populations and had decreased photosynthesis and respiration rates.
3) While calcification was not observed to decrease over the 28-day study, the cellular and physiological changes observed
Wan Marlin Rohalin, Nadzifah Yaakub and Najwa Mohd Fazdil. “Level of Zinc and Lead in Freshwater Fishes in Balok River, Pahang, Malaysia” United International Journal for Research & Technology (UIJRT) 1.1 (2019): 44-48.
Risk analysis the content of mercury (hg) in a water environmentTanty Puspa Sari
Terpaparrnya suatu zat dalam lingkungan sekarang ini dapat terjadi diberbagai jenis lingkungan. Salah satu zat yang dapat terpapar dalam suatu lingkungan adalah Hg atau biasa disebut merkuri. Merkuri merupakan unsur yang sangat jarang dalam kerak bumi, dan relatif terkonsentrasi pada beberapa daerah vulkanik dan endapan-endapan mineral biji dari logam-logam berat. Merkuri banyak terdapat di lingkungan terutama perairan.
Adapun cara penelitian yang digunakan adalah cross sectional, yaitu penelitian untuk mempelajari dinamika korelasi antara faktor-faktor resiko dengan efek, dengan cara pendekatan pengumpulan data atau studi literature. Adapun hasil penelitian kondisi air sungai di wilayah pertambangan Cisoka pada tahun 2005 (< 0,05 x 10-3 ppm Hg), berada di bawah baku mutu air menurut Peraturan Pemerintah No. 82 Tahun 2001 (< 0,001 ppm), sedangkan pada tahun 2011, kadar Hg rata-rata berada di atas baku mutu air yaitu 0,00392 ppm. Akibat banyaknya merkuri yang terdapat di lingkungan dapat mengakibatkan air berubah menjadi warna keruh dan tercemar. Adapun Solusi untuk mengurangi merkuri di perairan yaitu dengan Penanggulangan (pengendalian dan pencegahan) dampak pencemaran dilakukan dengan penataan kembali tata ruang
A bio refinery is a facility that converts biomass into multiple fuels, power, chemicals, and products. This report evaluates the feasibility of a bio refinery approach using algae. It discusses using algae grown in wastewater to produce electricity, biodiesel, biogas, and bioethanol. The bio refinery concept aims to reduce water usage, lower costs by using waste resources like CO2 and wastewater, and produce multiple revenue streams from algal biomass. While high upfront costs and concerns over algal toxins remain challenges, the report finds the bio refinery approach could provide sustainable fuel production and wastewater treatment.
E. coli O157:H7 was able to survive in irrigation water under varying physico-chemical conditions. It exhibited the highest survival at 1% NaCl but survival decreased with increasing NaCl concentration. pH 4 decreased survival over time while pH 9 allowed moderate survival. Iron enhanced survival in a concentration-dependent manner. Nitrate supported growth at 10 mg/L. Combinations of 5% NaCl and pH 4 or 10 mg/L iron and pH 9 further increased survival compared to individual parameters. E. coli was also able to enter a viable but non-culturable state and form biofilms, enabling long-term survival in irrigation water.
microbiological quality of water in aquaculture.RuksanaRukku
The document discusses the importance of water quality parameters for aquaculture. It notes that inadequate water quality can cause issues for production yields, fish health, and profits. It recommends testing water sources for parameters like ammonia, iron, alkalinity, and contaminants before establishing an aquaculture facility. It also suggests treating source water through aeration, filtration, ultraviolet sterilization, and activated carbon filtration to ensure the water can sustain life. Dissolved oxygen is identified as the most important chemical parameter, as low levels can cause fish stress and mortality. Methods for measuring chemical oxygen demand, total oxygen demand, and biochemical oxygen demand are also outlined.
This document summarizes a bio-hydrogen production process from agricultural waste. The process involves using sugar beet molasses and cow manure as feedstocks in dark and photo bioreactors to produce hydrogen through fermentation. The hydrogen is then purified, liquefied, and 38,800 kg can be produced per day. The process is projected to be economically viable and reduce carbon dioxide emissions compared to current hydrogen production methods. Key constraints and areas for further research and development are identified.
This document discusses Chlorella vulgaris and Ulva lactuca as potential sources for biodiesel and bioethanol production.
C. vulgaris is a microalgae that can be grown using photosynthesis. It contains lipids that can be extracted and converted to biodiesel via a transesterification process. U. lactuca is a type of macroalgae that contains polysaccharides like cellulose that can be broken down into sugars and fermented by yeast into bioethanol. The document outlines the steps involved in cultivating and processing these algae, as well as their economic and environmental benefits.
This presentation discusses biogas production from garbage through anaerobic digestion. It defines biogas as a combustible gas produced through biological breakdown of organic matter without oxygen. The presentation outlines the four stages of anaerobic digestion: hydrolysis, acidogenesis, acetogenesis, and methanogenesis. It also discusses factors that affect biogas production such as temperature, pH, carbon/nitrogen ratio, organic loading rate, and hydraulic retention time. Applications of biogas include electricity generation, transportation fuel, and cooking fuel.
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Heavy Metals in Sediment from Alvarado Lagoon System in Veracruz, MéxicoIJEAB
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In aquaculture, environmental impacts such as deteriorated water quality and poor pond bottoms are becoming challenging and omnipresent problems. This article highlights measures which can be taken to improve the quality of water and soil in aquaculture ponds, and therefore the immediate environment of fish and shrimp. Better rearing conditions will improve the overall performance of your fish and shrimp.
This document summarizes a study that investigated the bioaccumulation and distribution of organochlorine pesticide residues in the food web of Lagos Lagoon, Nigeria. Samples of water, sediment, plankton, benthic invertebrates, and fish were collected from four locations in the lagoon and analyzed for 18 organochlorine pesticides using gas chromatography. The highest concentrations of pesticides were found in sediment samples, with total concentrations up to 2,953.84 μg/kg. Pesticide concentrations increased higher up the food web, with the highest levels found in predatory fish species. The results indicate bioaccumulation and biomagnification of pesticides in the Lagos Lago
The document summarizes several biochemical routes for producing renewable fuels and chemicals, including anaerobic digestion, transesterification, and photofermentation. It discusses the key steps and microorganisms involved in anaerobic digestion, including hydrolysis, acidogenesis, acetogenesis, and methanogenesis. It also explains the transesterification reaction used to convert triglycerides to biodiesel and glycerin, and some of the process considerations for biodiesel production. Photofermentation is mentioned but not described.
The Contribution of Phytoplankton to the Primary Production in Floodplain Lak...Premier Publishers
This study aimed to estimate photosynthetic productivity of phytoplankton and water quality in two floodplain lakes of north Bihar, India. Gross phytoplankton productivity ranged from 1.849 g Cm-2day-1 to 4.994 g Cm-2day-1 at Tarawe chaur and 1.319 g Cm-2day-1 to 3.965 g Cm-2day-1 at Gamharia chaur. The net primary productivity measured as 1.037 g Cm-2day-1 to 3.849 g Cm-2day-1 at Tarawe chaur and 1.003 g Cm-2day-1 to 2.621 g Cm-2day-1 at Gamharia chaur. Primary productivity (GPP and NPP) of phytoplankton show a single annual peak. Respiration rates varied between 0.428 g Cm-2day-1 to 2.017 g Cm-2day-1 at Tarawe chaur and 0.489 g Cm-2day-1 to 1.475 g Cm-2day-1 at Gamharia chaur. Seasonal variation in phytoplankton gross and the net productivity was almost similar, highest in summer and lowest in winter. NPP/GPP ratio and respiration as percentage of gross production were computed. Physico-chemical parameters of water were analysed concurrently.
This document summarizes information about the enzyme urease. It discusses that urease is a nickel-containing metalloenzyme found in many organisms that catalyzes the hydrolysis of urea to produce ammonia and carbon dioxide. The active site contains two nickel ions that are bridged by ligands. Urease plays important roles in nitrogen cycling in soils and the digestive systems of ruminants and humans. Deficiencies in urease or related enzymes can cause health issues if not properly treated.
This study evaluated the effect of two methods of carbohydrate fertilization on nutrient discharge, sludge quantity and characteristics in biofloc shrimp culture. Six tanks were divided into two treatments - continuous molasses fertilization throughout cultivation (CONT) or initial molasses only in early weeks (INI). Both treatments stocked shrimp at 180 animals/m2 and cultured them for 12 weeks. The CONT treatment produced more total suspended solids (TSS) in sludge (0.25 kg/kg feed) than INI (0.16 kg/kg feed). Sludge from both treatments had high volatile solids but low carbon:nitrogen ratios and BOD:TSS ratios, indicating difficulty for anaerobic digestion treatment
This document discusses management and design considerations for producing shrimp in recirculating aquaculture systems. It outlines three main types of management regimes - chemoautotrophic, heterotrophic, and photoautotrophic - that differ in how they remove ammonia and utilize organic matter. Chemoautotrophic systems rely solely on nitrifying bacteria but do not support shrimp growth well. Heterotrophic systems use heterotrophic bacteria to remove ammonia and produce organic flocs to feed shrimp, allowing lower protein feeds. Photoautotrophic systems use algae but experience unstable swings that can stress shrimp. Design must account for the type of organic matter production and removal needed to support shrimp nutrition.
This study used Illumina sequencing of the 16S rRNA gene to analyze changes in the rumen microbiome of cattle subjected to feed restriction. The main findings were:
1) Feed restriction caused a large decrease in an abundant Succinivibrionaceae species and a significant increase in Methanobrevibacter gottschalkii.
2) Fifty-five days after being returned to a normal diet, the rumen microbiomes of previously restricted cattle were not different from controls, showing the disruption from restriction did not have long-term effects.
3) The rumen microbiome was not associated with compensatory growth in cattle 55 days after restriction ended.
1) The document summarizes research on the effect of different carbon sources on bio-floc formation in Pacific white shrimp culture.
2) It finds that Bacillus sp. bacteria were present in all treatments with added carbon sources. Molasses supported Alcaligenes, Bacillus, and Kurthia genera while tapioca supported Actinobacter and Bacillus.
3) Floc volume increased over time in all treatments until the end of the maintenance period, with tapioca and tapioca by-product treatments resulting in higher floc volumes.
The document discusses using bioremediation through biofilm and macrophyte management (BioMac) to improve water quality in a polluted tropical urban river in Brazil. Monitoring was conducted before and after installing BioMac structures. Results showed that after installation, there was a large decrease in nutrients along the river, increased transparency, biological diversity, and dissolved oxygen. This effect was strongest in the most polluted areas. It was concluded that the low-cost BioMac pilot system was effective at reducing phosphates, increasing nitrification, and improving water quality, making it a potential tool for depolluting rivers receiving sewage.
This document describes a project to design an energy-producing waste treatment system using anaerobic co-digestion of organic wastes from the University of Arkansas Swine and Poultry Units coupled with algae cultivation. A prototype was constructed and tested to generate data for designing a full-scale system. The full-scale system was designed to treat all biological wastes from the units while producing net energy and retaining nutrients that could be used as fertilizer.
The Cyprinids are the dominant species of culture fish worldwide accounting for over 20 million metric tons or 77 percent of the total aquaculture finfish production. The predominantly Asian consumption of this group of species makes them the most commonly eaten aquaculture species and importantly provides, as a food fish, a major source of basic protein to a large part of the world’s population.
This document discusses sewage-fed fish culture, which involves using treated sewage water to culture fish. It provides background on the history and present status of sewage-fed fish culture. The key processes involved are primary and secondary sewage treatment through sedimentation, dilution, and storage before releasing into fish ponds. Farmers culture various fish species using techniques like pond preparation, primary fertilization through sewage, stocking, feeding, and harvesting fish for market. While sewage-fed culture benefits waste recycling and low input costs, it can also pose health risks if not properly managed.
This document summarizes a project studying the use of red mud and pure metal oxides as potential catalysts for hydrothermal liquefaction (HTL) of food waste. The goal is to find a cheaper alternative to the commercial Ceria Zirconia catalyst. HTL converts biomass into liquid biofuel using water at high pressure and temperature. Previous studies show Ceria Zirconia improves biooil yield but is costly to reuse. Red mud, a low-cost byproduct, contains metal oxides that could achieve the desired base chemistry. The project will compare the impact of red mud and pure metal oxide catalysts to Ceria Zirconia on biooil production from food waste.
This study investigated nitrogen transformations in aquaponic systems under different conditions. The main findings were:
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2) Denitrification, the conversion of nitrates/nitrites to nitrogen gas, was found to be the major source of nitrogen loss. Higher dissolved oxygen and lower feeding rates decreased denitrification.
3) Isotopic analysis showed denitrification rates were higher under low dissolved oxygen conditions, as evidenced by higher nitrate δ15N values. This supported denitrification as the primary nitrogen loss pathway.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The document discusses FLOCponics, an alternative to aquaponics that integrates biofloc technology (BFT) with hydroponics. It provides background on the development of BFT and defines FLOCponics as integrating BFT-based aquaculture with hydroponics. Studies show that decoupled FLOCponics systems allow reducing protein levels in fish feed while maintaining yields. Economic analyses indicate that FLOCponics and aquaponics can both be profitable depending on marketable plant yields. The document also outlines optimal water quality parameters for aquaculture and reviews innovative studies on treating aquaculture effluents.
Factors affecting biogas production during anaerobic decomposition of brewery...Alexander Decker
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Rebecca Nelson and John Pade created the Aquaponics Journal 10 years ago and have provided a valuable service by advancing the aquaponics industry through their publication. To celebrate their achievement, the author compiled 10 important guidelines for aquaponic systems, including using a feeding rate ratio for design calculations, keeping feed input relatively constant, supplementing with calcium, potassium and iron, ensuring good aeration, removing solids, being careful with aggregates, oversizing pipes, using biological pest control, ensuring adequate biofiltration, and controlling pH.
Application of Low Protein Diet for Indonesian Shrimp FarmingSyauqy Nurul Aziz
Materi presentasi oleh Prof. Jeong-Dan Kim, Ph.D. dari Kangwon National University Korea pada Simposium Nasional Budidaya Udang Vanamei di Banyuwangi 2019
Development of integrated bioremediation and anaerobic digestion process usingIAEME Publication
This document discusses a study on the development of an integrated bioremediation and anaerobic digestion process using microalgae. Specifically, it examines using the microalgae Chlorella pyrenoidosa to treat biogas digester wastewater. The study finds that C. pyrenoidosa is able to grow well in biogas wastewater, removing up to 92.8% of nitrate nitrogen. The treated wastewater can then be used to support anaerobic digestion of the algal biomass to produce biogas. Co-digesting the microalgae with cow dung achieved higher biogas yields than digesting cow dung alone. Overall, the integrated process effectively treats biogas
This document is a thesis project examining innovative biological phosphate and anaerobic digestion technology for waste treatment, energy generation, and phosphorus recovery. It includes an abstract, introduction covering topics like sewage, current bioremediation methods, anaerobic digestion processes, low temperature anaerobic digestion, bioreactor configurations, and the global phosphorus crisis. It also outlines the materials and methods, expected results sections, and planned discussion. The introduction provides background on anaerobic digestion and examines its application to low-temperature wastewater treatment.
The biofloc is a protein-rich aggregate of organic material and microorganisms that forms in aquaculture systems. Biofloc technology maintains water quality and provides nutrients by balancing carbon and nitrogen through the addition of carbon sources like molasses. It has been successfully used in tilapia and shrimp farming and allows for high stocking densities through natural water treatment. Key factors that must be controlled include carbon to nitrogen ratio, dissolved oxygen, pH, and ammonia, nitrite and nitrate levels.
Download the Latest OSHA 10 Answers PDF : oyetrade.comNarendra Jayas
Latest OSHA 10 Test Question and Answers PDF for Construction and General Industry Exam.
Download the full set of 390 MCQ type question and answers - https://www.oyetrade.com/OSHA-10-Answers-2021.php
To Help OSHA 10 trainees to pass their pre-test and post-test we have prepared set of 390 question and answers called OSHA 10 Answers in downloadable PDF format. The OSHA 10 Answers question bank is prepared by our in-house highly experienced safety professionals and trainers. The OSHA 10 Answers document consists of 390 MCQ type question and answers updated for year 2024 exams.
The modification of an existing product or the formulation of a new product to fill a newly identified market niche or customer need are both examples of product development. This study generally developed and conducted the formulation of aramang baked products enriched with malunggay conducted by the researchers. Specifically, it answered the acceptability level in terms of taste, texture, flavor, odor, and color also the overall acceptability of enriched aramang baked products. The study used the frequency distribution for evaluators to determine the acceptability of enriched aramang baked products enriched with malunggay. As per sensory evaluation conducted by the researchers, it was proven that aramang baked products enriched with malunggay was acceptable in terms of Odor, Taste, Flavor, Color, and Texture. Based on the results of sensory evaluation of enriched aramang baked products proven that three (3) treatments were all highly acceptable in terms of variable Odor, Taste, Flavor, Color and Textures conducted by the researchers.
(Q)SAR Assessment Framework: Guidance for Assessing (Q)SAR Models and Predict...hannahthabet
The webinar provided an overview of the new OECD (Q)SAR Assessment Framework for evaluating the scientific validity of (Q)SAR models, predictions, and results from multiple predictions. The QAF provides assessment elements for existing principles for evaluating models, as well as new principles for evaluating predictions and results. In addition to the principles, assessment elements, and guidance for evaluating each element, the QAF includes a checklist for reporting assessments.
This new Framework provides regulators with a consistent and transparent approach for reviewing the use of (Q)SAR predictions in a regulatory context and increases the confidence to accept alternative methods for evaluating chemical hazards. The OECD worked closely together with the Istituto Superiore di Sanità (Italy) and the European Chemicals Agency (ECHA), supported by a variety of international experts to develop a checklist of criteria and guidance for evaluating each criterion. The aim of the QAF is to help establish confidence in the use of (Q)SARs in evaluating chemical safety, and was designed to be applicable irrespective of the modelling technique used to build the model, the predicted endpoint, and the intended regulatory purpose.
The webinar provided an overview of the project and presented the main aspects of the framework for assessing models and results based on individual or multiple predictions.
There is a tremendous amount of news being disseminated every day online about dangerous forever chemicals called PFAS. In this interview with a global PFAS testing expert, Geraint Williams of ALS, he and York Analytical President Michael Beckerich discuss the hot-button issues for the environmental engineering and consulting industry -- the wider range of PFAS contamination sites, new PFAS that are unregulated, and the compliance challenges ahead.
Widespread PFAS contamination requires stringent sampling and laboratory analyses by certified laboratories only -- whether it is for PFAS in soil, groundwater, wastewater or drinking water.
Contact us at York Analytical Laboratories for expert environmental testing with fast turnaround times and client service. We have 4 state-certified laboratories in Connecticut, New York and New Jersey, and 4 client service centers.
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A Comprehensive Guide on Cable Location Services Detections Method, Tools, an...Aussie Hydro-Vac Services
Explore Aussie Hydrovac's comprehensive cable location services, employing advanced tools like ground-penetrating radar and robotic CCTV crawlers for precise detection. Also offering aerial surveying solutions. Contact for reliable service in Australia.
Monitor indicators of genetic diversity from space using Earth Observation dataSpatial Genetics
Genetic diversity within and among populations is essential for species persistence. While targets and indicators for genetic diversity are captured in the Kunming-Montreal Global Biodiversity Framework, assessing genetic diversity across many species at national and regional scales remains challenging. Parties to the Convention on Biological Diversity (CBD) need accessible tools for reliable and efficient monitoring at relevant scales. Here, we describe how Earth Observation satellites (EO) make essential contributions to enable, accelerate, and improve genetic diversity monitoring and preservation. Specifically, we introduce a workflow integrating EO into existing genetic diversity monitoring strategies and present a set of examples where EO data is or can be integrated to improve assessment, monitoring, and conservation. We describe how available EO data can be integrated in innovative ways to support calculation of the genetic diversity indicators of the GBF monitoring framework and to inform management and monitoring decisions, especially in areas with limited research infrastructure or access. We also describe novel, integrative approaches to improve the indicators that can be implemented with the coming generation of EO data, and new capabilities that will provide unprecedented detail to characterize the changes to Earth’s surface and their implications for biodiversity, on a global scale.
1. Aquaculture 176 1999. 227–235
Carbonrnitrogen ratio as a control element in
aquaculture systems
Yoram Avnimelech )
Faculty of Agricultural Engineering, Technion, Israel Institute of Technology, Haifa 32000, Israel
Accepted 15 February 1999
Abstract
Controlling the inorganic nitrogen by manipulating the carbonrnitrogen ratios is a potential
control method for aquaculture systems. This approach seems to be a practical and inexpensive
means of reducing the accumulation of inorganic nitrogen in the pond. Nitrogen control is induced
by feeding bacteria with carbohydrates, and through the subsequent uptake of nitrogen from the
water, by the synthesis of microbial proteins. The relationship among the addition of carbo-hydrates,
the reduction of ammonium and the production of microbial proteins depends on the
microbial conversion coefficient, the CrN ratio in the microbial biomass, and the carbon contents
of the added material. The addition of carbonaceous substrate was found to reduce inorganic
nitrogen in shrimp experimental tanks and in tilapia commercial-scale ponds. It was found in
tilapia ponds that the produced microbial proteins are taken up by the fish. Thus, part of the feed
protein is replaced and feeding costs are reduced. The addition of carbohydrates, or the equivalent
reduction of proteins in the feed, can be quantitatively calculated and optimised, as shown here.
Approximate parameters were used in this work. Additional research in this field should be
directed at gathering the precise data needed for the exact planning of feed composition. q1999
Elsevier Science B.V. All rights reserved.
Keywords: CrN; Ammonium; Inorganic nitrogen; Microbial proteins; Feeding
1. Introduction
1.1. General
One of the major water quality problems in intensive aquaculture systems is the
accumulation of toxic inorganic nitrogenous species NH4q and NOy. in the water 2
) Tel.: q972-4-8292-480; Fax: q972-4-8221-529; E-mail: agyoram@tx.technion.ac.il
0044-8486r99r$ - see front matter q 1999 Elsevier Science B.V. All rights reserved.
PII: S0044- 848699.00085-X
2. 228 Y. AÍnimelechrAquaculture 176 (1999) 227–235
Colt and Armstrong, 1981.. Aquatic animals, such as fish and shrimp, excrete ammo-nium,
which may accumulate in the pond. A major source of ammonium is the typically
protein-rich feed. Aquatic animals need a high concentration of protein in the feed,
because their energy production pathway depends, to a large extent, on the oxidation and
catabolism of proteins Hepher, 1988.. In highly aerated ponds, ammonium is oxidised
by bacteria to nitrite and nitrate species. Unlike carbon dioxide which is released to the
air by diffusion or forced aeration, there is no effective mechanism to release the
nitrogenous metabolites out of the pond. Thus, intensification of aquaculture systems is
inherently associated with the enrichment of the water with respect to ammonium and
other inorganic nitrogenous species. The management of such systems depends on the
developing methods to remove these compounds from the pond.
One of the common solutions used to remove the excessive nitrogen is to frequently
exchange and replace the pond water. This approach is limited for three reasons:
a. Environmental regulations prohibit the release of the nutrient rich water into the
environment;
b. The danger of introducing pathogens into the external water;
c. The high expense of pumping huge amounts of water.
Another approach is based upon means to encourage and enhance nitrification of the
ammonium and nitrites to the relatively inert nitrate species. This is often done by
employing biofilters, essentially immobile surfaces serving as substrates to the nitrifying
bacteria. A high surface area with immobilised nitrifying biomass enables a high
nitrifying capacity in a controlled environment. One problem associated with biofiltra-tion
is the high cost involved and the need to treat and digest a large mass of feed
residues. Effectively, about 50% of the feed material added to the pond needs to be
digested.
An additional strategy that is presently getting more attention is the removal of
ammonium from the water through its assimilation into microbial proteins by the
addition of carbonaceous materials to the system. If properly adjusted, added carbo-hydrates
can potentially eliminate the problem of inorganic nitrogen accumulation. A
further important aspect of this process is the potential utilization of microbial protein as
a source of feed protein for fish or shrimp.
Utilization of microbial protein depends upon the ability of the animal to harvest the
bacteria and its ability to digest and utilise the microbial protein. Neither are trivial. One
obvious problem is determined by the minimal size of particles that can be taken up by
the fish. Schroeder 1978. reported that carp can filter out particles larger than 20–50
mm. Odum 1968. reported that Mugil cephalus take up particles as small as 10 mm.
An interesting observation was made by Taghon 1982., who found that benthic
invertebrates were able to take up microscopic glass beads when they were coated with
proteins. This demonstrates that the chemical nature of the particle may favor its
harvesting by fish. The fact that relatively large microbial cell clusters are formed due to
flocculation of the cells, alone or in combination with clay or feed particles Harris and
Mitchell, 1973; Avnimelech et al., 1982., additionally favors cell uptake by fish.
The adjustment of the CrN ratio in the feed, as a means to control the pond water
quality, is presently under active research in many research centers e.g., presentations in
the last WAS meeting: McGoogan and Galtin, 1998; Rudacille and Kohler, 1998;
3. Y. AÍnimelechrAquaculture 176 (1999) 227–235 229
Conquest et al., 1998.. The objectives of this paper are to formulate the basic reactions
and mechanisms affecting this process; to demonstrate its potential; to develop the
quantitative means needed to adjust the CrN ratio; and to control inorganic nitrogen
accumulation in ponds.
1.2. Theory
The control of inorganic nitrogen accumulation in ponds is based upon carbon
metabolism and nitrogen-immobilizing microbial processes. Bacteria and other microor-
ganisms use carbohydrates sugars, starch and cellulose. as a food, to generate energy
and to grow, i.e., to produce proteins and new cells:
organicCªCO qenergyqCassimilated in microbial cells. 1. 2
The percentage of the assimilated carbon with respect to the metabolised feed carbon, is
defined as the microbial conversion efficiency E. and is in the range of 40–60% Paul
and van Veen, 1978; Gaudy and Gaudy, 1980.. Nitrogen is also required since the major
component of the new cell material is protein. Thus, microbial utilization of carbo-
hydrate or any other low nitrogen feed. is accompanied by the immobilization of
inorganic nitrogen. This process is a basic microbial process and practically every
microbial assemblage performs it.
The addition of carbohydrates is a potential means to reduce the concentration of
inorganic nitrogen in intensive aquaculture systems. The amount of carbohydrate
addition DCH. needed to reduce the ammonium can easily be evaluated.
According to Eq. 1. and to the definition of the microbial conversion coefficient, E,
the potential amount of microbial carbon assimilation, when a given amount of
carbohydrate is metabolised DCH., is:
DC sDCH=%C=E, 2. mic
where DC is the amount of carbon assimilated by microorganisms and %C is the mic
carbon content of the added carbohydrate roughly 50% for most substrates..
The amount of nitrogen needed for the production of new cell material DN. depends
on the CrN ratio in the microbial biomass which is about 4 Gaudy and Gaudy, 1980.:
DNsDC rwCrNx sDCH=%C=ErwCrNx , 3. mic mic mic
and using approximate values of %C, E and wCrNx as 0.5, 0.4 and 4, respectively.: mic
DCHsDNr0.5=0.4r4.sDNr0.05. 4.
According to Eq. 4., and assuming that the added carbohydrate contains 50% C, the CH
addition needed to reduce total ammonia nitrogen TAN. concentration by 1 ppm N i.e.,
1 g Nrm3. is 20 grm3.
A different approach is to estimate the amount of carbohydrate that has to be added in
order to immobilise the ammonium excreted by the fish or shrimp. It was found that fish
or shrimp in a pond Avnimelech and Lacher, 1979; Boyd, 1985; Muthuwani and Lin,
1996. assimilate only about 25% of the nitrogen added in the feed. The rest is excreted
as NH or as organic N in feces or feed residue. It can be assumed that the ammonium 4
4. 230 Y. AÍnimelechrAquaculture 176 (1999) 227–235
flux into the water, DNH , directly by excretion or indirectly by microbial degradation 4
of the organic N residues, is roughly 50% of the feed nitrogen flux:
DNsfeed=%Nfeed=%Nexcretion. 5.
A partial water exchange or removal of sludge reduces the ammonium flux in a
manner that can be calculated or estimated. In zero exchange ponds, all the ammonium
remain in the pond. The amount of carbohydrate addition needed to assimilate the
ammonium flux into microbial proteins is calculated using Eqs. 4. and 5.:
DCHsfeed=%Nfeed=%Nexcretionr0.05. 6.
The CrN ratio, or the equivalent protein concentration of the feed, can be calculated
using the derived Eq. 6.. Assuming 30% protein feed pellets 4.65% N. and 50% of the
feed nitrogen are excreted %N excretion., we get:
DCHsfeed=0.0465=0.5r0.05s0.465=feed. 7.
According to Eq. 7., the feed having 30% protein should be amended by an
additional portion of 46.5% made of carbohydrates with no protein. The corrected
protein percentage should accordingly be:
corrected protein percentages30%r1.465s20.48%, 8.
and the original CrN ratio 10.75 in the 30% protein feed. should be raised to 15.75.
2. Materials and methods
Several experimental results are presented, in order to demonstrate and substantiate
the theoretical approach developed.
The basic process of microbial ammonium immobilization was demonstrated in a
laboratory experiment where pond sediment suspension was enriched with ammonium
salt. Twenty-gram samples of pond bottom clay soil, from commercial tilapia pond.
were shaken for 12 h with 1000 ml tap-water enriched with NH . SO , at an initial 4 2 4
concentration of about 10 mgrl, and 200 mgrl glucose. Samples were taken periodi-cally
and filtered. Ammonium concentrations were determined according to standard
methods using an auto-analyzer EPA, 1974..
The effects of carbohydrates addition on ammonium accumulation in a dense shrimp
culture were tested in 25 m2 indoor tanks stocked with 0.8 kgrm2 Penaeus monodon.
Shrimp were fed with pellets containing 40% protein at a daily rate of 2% body weight
i.e., 16 g feed, 6.4 g protein or daily 0.96 g Nrm2. It was assumed that 33% of the feed
nitrogen is excreted. Sugar glucose. or cassava meal were added at a rate of seven times
the expected ammonium excretion, i.e., daily 2.2 grm2. The experiment was conducted
in triplicates.
The effects of changing the CrN ratio in the feed on the growth and feed utilization
in tilapia are shown in data adapted in part from previous research. In the first
experiment Avnimelech et al., 1989., tilapia grown in tanks were fed by either:
I. Conventional feed pellets with 30% protein;
II. Pellets made of wheat meal 10% protein.; and
5. Y. AÍnimelechrAquaculture 176 (1999) 227–235 231
III. Feeding with 10% protein pellets at one-half the daily ratios as compared to
treatment II., amended by daily additions of cellulose powder and NH . SO . 4 2 4
Protein, fat and stable carbon isotopes were determined in fish tissue at the end of the
experimental period.
The second experiment Avnimelech et al., 1994. was a pond experiment where
tilapia were grown in circular 50 m2 ponds at a density of about 10 kgrm2. Fish were
fed using conventional 30% protein pellets CrNs11.1. or a tested formulation of low
protein diet of 20% protein CrNs16.7.. The daily feed addition was 2% of body
weight for the conventional feed and 2.6%, to include carbohydrates needed for the
microbial ammonium conversion, with the low protein pellets. The results presented
here, partially recalculated from the original report, summarise two triplicated experi-ments.
3. Results and discussion
The effect of addition of carbohydrates on the immobilization of TAN was demon-strated
in a laboratory experiment consisting of a sediment suspension amended with
ammonium about 10 mgrl. and glucose at a concentration 20 times higher than that of
the TAN. It was found Fig. 1. that almost all the added ammonium disappeared over a
period of about 2 h, following a short lag period, with no concomitant production of
NOy or NOy not shown.. 2 3
The addition of carbohydrates to control nitrogen concentrations in shrimp ponds was
tested in tanks containing dense 0.8 kgrm2 . shrimp biomass. Sugar glucose. and
cassava meal were added to reduce TAN accumulation. The carbonaceous substrates
additions were calculated assuming an ammonium excretion equivalent to 33% of the
feed a significant underestimation of ammonium excretion.. The carbonaceous sub-
Fig. 1. Changes in TAN concentration in a suspension of pond bottom soil 2% dry soil. following the addition
of glucose TANrglucose ratio of 1r20..
6. 232 Y. AÍnimelechrAquaculture 176 (1999) 227–235
Fig. 2. Changes with time of TAN concentration in shrimp tank experiment. The shrimp biomass was 0.8
kgrm2. The control tank was supplied with 40% protein pellets. Carbohydrates glucose, cassava meal. were
added daily at a rate of seven times the assumed TAN excretion by the shrimps.
strates addition led to a significant reduction in the accumulation of ammonium in the
tanks Fig. 2.. Nitrates and nitrites were also reduced, from 1.97 mg NO qNO .yNrl 3 2
in the control treatment to 1.13 mg NO qNO .yNrl in the treatment tank. 3 2
Results of tank experiment comparing growth and body composition of tilapia fed
with I. conventional pellets, II. control, 10% protein pellets, made from wheat flour,
and III. 10% protein pelletsqcellulose powderqNH . SO are given in Table 1. 4 2 4
Detailed results were published elsewhere Avnimelech and Mokady, 1988; Avnimelech
et al., 1989.. Bacterial flocculation was observed, probably supporting filtering out by
the fish, and thus supplying protein that was available and suitable to fish nutrition.
Though tilapia do not digest cellulose, it was found that the addition of cellulose
supported fish growth, obviously through the ingestion and digestion of bacteria growing
on the cellulose. Daily growth of tilapia fingerlings was 0.5, 0.12 and 0.33% for diets I,
Table 1
Tilapia feeding with microbial protein
Treatment
I. Conventional II. Control III. Test
pellets pellets pellets
Daily growth % 0.5 0.12 0.33
Protein % in muscle 15.5 14.2 15.9
Fat % in muscle 4.2 4.3 2.6
d13C in feed % y13.8 y14.8 y23.5 cellulose.
13 d C in fish muscle % y20.8 y20.5 y23.0
Growth and feed utilization data for fish fed with I. conventional 30% protein pellets; II. 10% protein pellets;
and III. test treatments of 10% protein pelletsqcellulose powderqNH4 .2SO4 , as a substrate for the
production of microbial proteins.
7. Y. AÍnimelechrAquaculture 176 (1999) 227–235 233
II and III, respectively. Protein content of the fish in the control treatment II. was low,
yet that in fish fed with microbial protein III. was as high as with conventional feeding
II.. Carbon isotopes distribution in the feed materials and fish tissues indicated that the
fish digested and ingested carbon derived from the cellulose, most probably by uptake of
the microbial proteins.
Following the pilot scale work, a series of pond scale experiments was conducted.
Results presented here are adapted from Avnimelech et al., 1992, 1994.. It was found
that the addition of carbohydrates, essentially changing the 30% protein feed material to
20% protein feed, led to:
a. a significant reduction of inorganic nitrogen accumulation;
b. increased utilization of protein feed;
c. a significant reduction of feed expenditure.
Fish growth and feed utilization data in two triplicated pond experiments 50 m2
ponds stocked with tilapia hybrids at a density of 80 fishrm2 . are given in Table 2. It
can be seen that fish growth was better in the 20% protein treatment, most likely due to
the lower concentrations of toxic inorganic nitrogen species. In addition to a lower feed
conversion ratio FCR., the protein conversion ratio PCR. was markedly reduced in the
20% protein treatment. The PCR in the conventional 30% protein feed treatment was
4.35–4.38, meaning that only 23% of the feed protein was recovered by the fish. The
Table 2
Fish growth and yield coefficients of tilapia fed with conventional pellets 30% protein, CrNs11.1. and low
protein pellets 20% protein, CrNs16.6. in two pond experiments
Treatment
Conventional feeding C-enriched
30% protein. 20% protein.
Experiment no. 1: 51 days, aÍerage of three replicates
Feed CrN ratio 11.1 16.6
Fish weight grfish.
Initial weight 112 112
Final weight 193 218
Daily gainU 1.59a 2.0b
Mortality %. 14.6 10.3
Feed conversion coefficient 2.62 2.17
Protein conversion coefficient 4.38 2.42
Feed cost coefficient US$rkg fish. 0.848 0.583
Experiment no. 2: 30 days, aÍerage of three replicates
Fish weight grfish.
Initial weight 205 205
Final weight 254 272
Daily gainU 1.63a 2.22b
Mortality %. 3.4 0
Feed conversion coefficient 2.62 2.02
Protein conversion coefficient 4.35 2.18
Feed cost coefficient US$rkg fish. 0.848 0.543
UValues not sharing a common letter differ significantly p-0.05..
8. 234 Y. AÍnimelechrAquaculture 176 (1999) 227–235
PCR in the tested treatment was 2.2–2.4, i.e., protein utilization was twice as high. The
increased protein utilization is due to its recycling by the microorganisms. It may be said
that the proteins are eaten by the fish twice, first in the feed and then harvested again as
microbial proteins. It is possible that protein recycling and utilization can be further
increased.
Due to the fact that proteins are the expensive component of the feed, its reduction
was reflected in the feed price which decreased from US$0.85rkg fish to about
US$0.55rkg Table 2.. Similar results were obtained recently in the desert aquaculture
farms that are operated following principles presented here Avnimelech et al., unpub-
lished data..
4. Conclusions
Controlling the inorganic nitrogen by manipulating the carbonrnitrogen ratios is a
potential control method for aquaculture systems. This approach seems to be a practical
and inexpensive means to reduce the accumulation of inorganic nitrogen in the pond.
Such a strategy can be practiced as an emergency response, i.e., addition of a
carbonaceous substrate in case of increased ammonium concentration. It is possible to
add cheap sources of carbohydrates e.g., cassava meal, flor. in cases such as a series of
cloudy days slowing down algae growth, or severe algae crash. However, additional
pond aeration may be required to compensate for the additional oxygen consumption.
The conventional control means for ponds are to intensively exchange the water, a
strategy that is not always practical, and to stop feeding to slow down TAN build up.
The proposed method enables keeping a high biomass and to have a corrective means in
case of a failure of conventional controls.
A more advanced approach is to adjust the protein level in the feed so as to avoid the
build up of inorganic nitrogen in the water. This approach was tested and proven
successful in intensive ponds that are continually mixed and aerated. The intensive
culture of fish in these ponds is based on a system that is similar to biotechnological
reactors. Such systems are amendable to a set of controls similar to biotechnological
controls Avnimelech, 1998.. The ability to control inorganic nitrogen concentrations
through the manipulation of CrN ratios in the system is one example of such a control.
The addition of carbohydrates was done as a part of the feeding scheme. In this case, the
addition of carbonaceous substrate leads to the recycling and increased utilization of
proteins through the utilization of the microbial proteins. Production and utilization of
microbial proteins SCP, single-cell protein. have been studied extensively during the
last few decades e.g., Tannenbaum and Wang, 1975.. The major problem involved in
economically sound utilization of SCP cultures is the harvesting, dehydration and
packaging of the material. In contrast, for in situ microbial protein culturing in the pond,
all of these expensive processing stages are not needed since harvesting is done by the
fish, as part of the system.
The applicability of the same approach in earthen stagnant ponds is not trivial and has
to be further studied in conventional fish and shrimp ponds. The addition of carbo-hydrates
to the feed may result in an accelerated sedimentation of organic matter to the
9. Y. AÍnimelechrAquaculture 176 (1999) 227–235 235
pond bottom, where the microbial biomass will not be utilised by the fish and will
increase the organic load in the pond.
The addition of carbohydrates, or the equivalent reduction of proteins in the feed, can
be quantitatively calculated and optimised, as shown in Eqs. 6.–8.. However, approxi-mate
parameters were used in this work. Additional research in this field should be
directed at gathering precise data needed for the exact planning of feed composition and
feeding rate.
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