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The role of bioremediation in water quality management

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With the expansion and development of the aquaculture industry, several challenges arise. The intensification of production systems increases the pressure on the environment, which can severely affect …

With the expansion and development of the aquaculture industry, several challenges arise. The intensification of production systems increases the pressure on the environment, which can severely affect water quality and as a consequence fish or shrimp performance and the incidence of diseases.

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  • 1. I N C O R P O R AT I N G f i s h far m ing t e c h no l og y March | April 2013The role of bioremediation in water quality management International Aquafeed is published six times a year by Perendale Publishers Ltd of the United Kingdom. All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies, the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of information published. ©Copyright 2013 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1464-0058The International magazine for the aquaculture feed industry
  • 2. Fatten up your bottom line. Bühler high-performance animal and aqua feed productionsystems are used by leading companies around the world. These producers know theycan rely not just on the technology itself, but also on the support that accompanies it. Aservice combining local presence with global expertise both lowers feed mill operatingcosts and increases capacity utilization. To find out more, visit www.buhlergroup.comBühler AG, Feed & Biomass, CH-9240 Uzwil, Switzerland, T +41 71 955 11 11, F +41 71 955 28 96fu.buz@buhlergroup.com, www.buhlergroup.comInnovations for a better world.
  • 3. FEATUREThe role ofbioremediation in waterquality managementby Goncalo A. Santos, MSc, technical manager – aquaculture, BiominHolding GmbH, AustriaW ith the expansion and devel- decreased anaerobic conditions in pond soil example, the formation of glutamine in the opment of the aquaculture and reduced sludge accumulation. brain to detoxify ammonium to urea, to industry, several challenges Moreover, enzymes can be an effective protect themselves from toxic ammonia levels arise. The intensification of tool in the degradation of organic matter (Randall and Tsui, 2002). Nitrite (NO2-) is production systems increases the pressure in very intensive production systems. These usually present below dangerous concentra-on the environment, which can severely positive changes in the environment are sup- tions in fresh and marine water. affect water quality and as a consequence ported by proven benefits for the perform- However, prolonged exposure to high fish or shrimp performance and the inci- ance and survival of shrimp from the larval to nitrite levels, especially when oxygen is limited, dence of diseases. grow-out stages. leads to anoxia and slow suffocation of the animals, because nitrite changes hemoglobin In aquaculture, the application of beneficial Toxicity of nitrogenous into methemoglobin, a form that is not able to bacteria (probiotics) is not only associated compounds bind oxygen (Lewis and Morris, 1986). with gut health (feed probiotics), but also Nitrogen compounds, such as nitrite, Nitrate (NO3-) is the least dangerous with bioremediation improving the environ- nitrate and ammonium ions / ammonia are compound and low concentrations are not ment (water and soil) in which the animals toxic when their concentrations exceed a problematic. Similar to nitrite, nitrate converts are reared. The effects of biodegrading strains certain level in the rearing water. Ammonium hemoglobin, into a non-binder for oxygen. (such as Bacillus sp., Paracoccus sp., Thiobacillus nitrogen that occurs partly in the form of Permanent exposure to high nitrate levels sp.) added directly to the water involve the ammonium ion (NH4+) and ammonia causes weight loss and a higher occurrence of modulation of the microbiology profile in (NH3+) originates from decomposing organic infectious diseases. To avoid these complica-ponds, degradation of undesirable waste com- waste and animal excretions in the farm. The tions, excess nitrate needs to be removed pounds (ammonia, nitrite, hydrogen sulfide), sensitivity to ammonium nitrogen depends to reach lower, non-toxic concentrations enhanced mineralization of organic matter, largely on the species. (Camarga et al., 2005). This is often achieved Some fish have developed strategies, for by water renewal at the farms. Bioremediation in aquaculture Watewater management in aquaculture systems is crucial to maintain a good health status of the animals as well as to counteract the negative impacts on the environment. Bioremediation, the application of micro- organisms like bacteria to remove dangerous waste products, is a promising tool for onsite treatment of watewater and contaminated sediments. For the bioremediation of nitrog- enous compounds, bacteria have to perform nitrification and denitrification. Bacterial nitrifica- tion is the oxidation of ammonium / ammonia Figure 1: Nitrification and denitrification (NH4+, NH3+) to nitrate (NO3-) via hydroxyl processes in aquatic environments amine and nitrite (NO2-). Denitrification 28 | InternAtIonAl AquAFeed | March-April 2013
  • 4. FEATURE FEATURE duced on a large scale it could bring fish uniqueness of the technology is based on its carbon dioxide. In particular, oversaturation production to the place where the fish is ability to perform three critical functions in of nitrogen, even in relatively small quantities, actually consumed. one system - dissolving oxygen in the water, can endanger the wellbeing of fish stock, slow- The Marine Harvest Group, the worlds producing the correct marine hydrodynamics ing growth and increasing the possibility of largest private fish producer, is building ever- and stripping out potentially harmful nitrogen disease, and ultimately, even mortality. With larger tanks. At Kårstø, Norway, the company - and all this via a very low energy require- the installation of OxyStream, external degas- has plans to produce 6,000 tons of salmon ment. The system is easily installed, as a new sing units to prevent inert gas build-up will, in per year, onshore, to an average size of 1 set-up or as a retrofit to existing fish farm many cases, become obsolete. kilogram, in fish tanks 40 metres in diameter tanks, and is maintenance-free because it is Depending on the application, pumping and 10 metres high, with volumes of water as not associated with any ancillary equipment pressures as low as 0.05 to 0.2 bar are nor- high as 12,000 cubic metres. Marine Harvest to manage water pressure. mally sufficient to oxygenate the incoming also intends to explore the possibility of SOLVOX ® OxyStream significantly water, strip nitrogen and create optimal tank building a land based fish farm in a quarry at increases fish production volume, optimises hydrodynamics. This low operating pressure Mjølkevikvarden, in 2: Pond Norway, where fish meat quality and considerably improves Figure Askøy, interactions without the addition of Figure 3: Pond interactions with the makes the system very energy efficient. the company believes there is potential to beneficial bacteria operations from an environmental standpoint. The addition of beneficial bacteria were capabilities of this technology build a plant big enough to produce 50,000 It is a combined oxygenation and flow system proved during trials conducted at a Marine tons per year of 1 kilogram salmon. nitrous describes the reduction of nitrate to compounds is more likely to ensure a amount that not only dissolves the optimal stable are constantly exposed Results showed that Harvest facility in 2011. to and challenged This is equal to 5 percent of the total oxide and finally to nitrogen gas, which returns performance.in the inlet water flow, but also of oxygen OxyStream was the only oxygenation source by micro-organisms from the surrounding into the atmosphere (Chávez-Crooker trout biomass production of salmon and and distributes it evenly at an adjustable flow pat- environment. rearing young salmon hatched in suitable for Obreque-Contreras, — currently about range in Norway today 2010). Although a 1 mil- Beneficial bacteria and enzymes tern throughout the tank, ensuring that the tanks running on fresh water, before gradually These environmental challenges are of bacterial species are Theoretically, if 20 of lion tons per year. capable of nitrification to improve water and soil exercise fish stock benefit from the physical transitioning them to seawater. This creates obviously influenced by different factors, these plants where in operation today, all of and / or denitrification, not all species are appli- quality in aquaculture ponds The involved in swimming against the flow. an optimum environment in and to rear including farm management which rearing Norway’s salmon production to full slaughter cable for bioremediation products. Recently flow key factor for successful aquaculture is A regime can be fully tailored according salmon, ensuring the correct oxygen levels methods. Aquaculture operations generally size could be accomplished on land. Key strains such as Paracoccus sp. and Thiobacillus sp. to understand stock density and fish species, to fish size, the interactions between the throughout the entire production period and involve the stocking and feeding of shrimp parameters associated with this installation have gained interest due to its degrading capa- such as salmon or cod. The system comprises microbial environment, gut flora and immune in open fish semi-closed water systems. keeping or stress levels to an absolute are 20,000 cubic metre fish tanks, 35 metres bilities. Also Bacillus sp. is also well suited to a standalone unit, allowing water flow and system of the shrimp, as well as the factors minimum. Semi-closed pond systems have a low in diameter.perform several functions in the water cleanup that determine the be individually microbial oxygen dosing to persistence of controlled Importantly, the technology makes it pos- water turnover and can accumulate gases, application (Nakano et al., 1998). for each tank. species in the internal and external microbial nutrients, precisely predict flow etc., which sible to metabolites, waste, velocity and Pioneering technology all desired A single strain, rarely harbours The micro-bubbles created by SOLVOX® ecosystems. While natural environments are can adjust this velocity in the circular on-land to deteriorate the water quality and qualities necessary for an efficient degradation One of the most pioneering technologies balanced, the farming environment favours OxyStream create the additional benefit of create anoxic conditions in state of matu- tanks, Depending on their the soil. This of toxic compounds, therefore a combination to be introduced to the industry has been the growth of micro-organisms as it is rich helping to reduce the concentration of dis- rity, fish need a certain water velocity to can strongly affect the performance of the Linde’s SOLVOX® OxyStream system. The of strains that perform best for one or several in nutrients and feed waste. Farmed species solved inert gases such as nitrogen, argon and remain healthy. If the velocity is not correct, farmed species. Thus, good pond manage- Extruder OEE for the Production of Fish Feed - AMANDUS KAHL GmbH & Co. KG, Dieselstrasse 5-9, D-21465 Reinbek / Hamburg, Phone: +49 40 727 71 0, Fax: +49 40 727 71 100, info@amandus-kahl-group.de www.akahl.de March-April 2013 | InternAtIonAl AquAFeed | 29 March-April 2013 | InternAtIonAl AquAFeed | 11
  • 5. FEATURETable 1: A diverse range of enzymes used asbioremediation agents in aquacultureenzyme substrateamy;lase ß-GlucosideCellulase Celluloselipase lipids and fatProtease ProtienXylanase Xylan, HemicellulosePeectinase Pectinment is crucial for high production and a healthy crop. Since water quality plays an important role, it is of great value to understand the various interactions taking place within the ponds. These are quite complex and depend directly on the pond environment, stocked biomass, input of nutrients and pond management. pathogens to grow and affecting the condition the level of such toxic compounds. Some As can be seen in Figure 2, the accumula- of the shrimp. Under these poor conditions, beneficial bacteria can also degrade toxic H2S, tion and degradation of organic waste in the the shrimp faces higher levels of stress and improving water quality and odor. The com-pond will result in an increased consumption is more susceptible to diseases, which could bination of all these factors will improve water of oxygen (O2) and production of waste result in poor growth or a failed crop through quality and the condition of the pond soil, compounds such as ammonia (NH3), nitrites disease outbreaks. resulting in a better environment for shrimp (NO2 -) and hydrogen sulfide (H2S), which With the inclusion of beneficial bacteria with better growth and health status.can lead to a phytoplankton bloom. Massive (Figure 3), organic matter is utilized as a In the bioremediation process, enzymes growth of phytoplankton can further deplete source of nutrients by the bioremediation play the role of catalysts that accelerate oxygen during the night and contribute to a bacteria, which reduces the amount of waste biochemical reactions in pond soil and water. phytoplankton bloom crash. All these factors accumulating in the pond. Additionally, specific When added to the culture water or spread contribute to the contamination of water nitrifying and denitrifying bacteria will convert on top of the pond soil, enzymes are able and soil, creating favourable conditions for NH3 and NO2- into nitrogen gas, reducing to degrade the major organic constituents normally found in shrimp and fish ponds. Each enzyme has its mode of action and is very specific in the chemical reaction it catalyzes (Table 1). Enzymes are also naturally produced and excreted by some microbes. These extracel- lular enzymes, such as cellulase, protease and amylase, are produced during the aerobic fer- mentation of organic matter by micro-organ- isms, for example by some Bacillus species. Bacilli are commonly found in pond sediments and can also be added to the pond water for bioremediation purposes. Some Bacillus sp. are also able to degrade nitrogenous compounds. In addition, their large variety of excreted (extracellular) enzymes helps to speed up the degradation of organic matter and toxic com- pounds such as ammonia. The efficient removal of nitrogenous compounds can also be carried out by nitrifying and denitrifying bacteria such as Figure 4: Average growth rate (g/day) of shrimp during the production period Thiobacillus and Paracoccus. 30 | InternAtIonAl AquAFeed | March-April 2013
  • 6. FEATURE While some micro-organisms proliferate in breaking apart large sludge particles, thus the soil of the control ponds in Picture 2 a narrow range of environmental conditions creating wider surface areas which can then exhibited a dark black colour, an indica-(pH, oxygen, availability, etc.), certain enzymes be fermented by microbes. This reduction tion of the accumulation of dead organic are able to act in multiple environments. of sludge and dead organic matter can be matter. Nevertheless, some products combining seen visually not only through better water Results suggested that with the combined the positive effects of beneficial bacteria and quality, but also through better soil quality. use of beneficial bacteria and enzymes, pond enzymes are already being used as bioreme- soils containing black and glutinous organic diation agents in aquaculture. Field trial sludge turned into a more yellow soil. In a field study in China, it was observed In terms of performance, the average daily Efficacy of enzymes in that the combined application of the weight gain of shrimp in the AquaStar® group bioremediation bioremediation products AquaStar® Pond increased by 36 percent and feed conversion Enzymes have the capacity to stabilize (Bacillus sp., Enterococcus sp.,Pediococcus ratio improved by 9 percent compared with the soil organic matter and can be used sp., Paracoccus sp., Thiobacillus sp) and the control (no probiotic inclusion). The effectively to manage soil quality and rear- AquaStar® PondZyme (beneficial bacteria results are shown in Figure 4 and 5. ing conditions for aquatic species. There is and a blend of amylases, xylanases, cellulases Based on these results, it was concluded not one specific enzyme that works best and proteases) to the water, according to that in the search for more effective and in all cases. A blend containing a variety of a specific application programme, improved environmentally-friendly treatments, benefi-enzymes may be the most effective means water quality, soil condition and ultimately, cial bacteria have emerged as a viable alter-for bioremediation in aquaculture. Enzymes shrimp performance. native. The application of bioremediation greatly reduce sludge accumulation and Four earth shrimp ponds (0.7 – 0.8 ha/ solutions in aquaculture can also benefit anaerobic conditions in pond bottoms. pond) with a depth of 1 – 1.2 m were from the inclusion of enzymes, especially in They promote a faster degradation of stocked with juvenile shrimp (approximately intensive productions. AquaStar® positively the accumulated organic matter especially 1.4 g/shrimp) with a density of 50 shrimp/ affects the performance of shrimp while under intensive production conditions. m². The trial was carried out for a period maintaining a stable environment in the This organic matter comprises uneaten of 57 days with a dosage of 500 g/ha of pond, proving to be an effective manage-feed, dead plankton, mineral soils, faeces product applied once a month to the ment tool in aquaculture.and pathogenic micro-organisms in the soil treatment group (two ponds). The control where the conditions are often anaerobic. ponds consisted of two ponds with normal However, for all these bioremediation proc- production operations.esses catalyzed by enzymes, the presence The soil of the AquaStar® ponds in More InforMatIon:of beneficial bacteria is important as well. Picture 1 was of yellow colour which is Website: www.biomin.netEnzymes accelerate microbial processes by regarded as the best bottom type, while Ecobiol Aqua Vi sit VI Bo NO V o R H ASI th a EL 10 A t 5.G 2 10 013 8 A highly effective new generation probiotic Pathogenic bacteria antagonist Enhances friendly intestinal microflora Improves Feed Conversion Ratio and growth Helps mantain optimal health status Reduces mortality in the ponds Controls water quality Central Office and Orders Jesús Aprendiz, 19. 1º A-B 28007 Madrid T. +34 915 014 041 norel@norel.es www.norel.es March-April 2013 | InternAtIonAl AquAFeed | 31
  • 7. This digital re-print is part of the March | April 2013 edition of International LINKSAquafeed magazine. Content from the magazine is available to view free-of-charge, both as a fullonline magazine on our website, and as an archive of individual features onthe docstoc website.Please click here to view our other publications on www.docstoc.com. I N C O R P O R AT I N G f I s h fA R m I N G T e C h N O l O G y • See the full issue Transforming aquaculture production using • Visit the International Aquafeed website oxygenation systems • Contact the International Aquafeed Team Nutritional benefits of processed animal proteins – in European aquafeeds Bioenergetics – application in aquaculture nutrition Towards aquafeeds with increased food security • Subscribe to International Aquafeed Vo l u m e 1 6 I s s u e 2 2 0 1 3 - mARCH | APRIlTo purchase a paper copy of the magazine, or to subscribe to the paperedition please contact our Circulation and Subscriptions Manager on the linkabove. INFORMATION FOR ADVERTISERS - CLICK HERE www.aquafeed.co.uk