electrocoagulation used in treatment of biogas reactor
ELECTROCOAGULATION USED IN TREATMENT OF BIOGAS REACTOR LIQUID WASTE A.TETREAULT*, T. ØIAN*, J. K. REISTAD**, K. HAARSTAD*** *EC NORWAY AS, Verksgaten 54, 4013 Stavanger, Norway ** HADELAND OG RINGERIKE AVFALLSELSKAP, Sevnaker 3520, Norway ***NIBIO, Norwegian Institute for Bioeconomy, N-1430 Ås, Norway
SUMMARY: The paper presents the results of electrocoagulation treatment of wastewater resulting from the biogas production generated at the Hadeland and Ringerike Waste Management (HRA) plant in Norway, performed by EC Norway AS, a Norwegian company working closely with the Australian company EC Pacific Pty Ltd. The biogas reactor wastewater is highly concentrated. In the absence of a suitable treatment or means of concentration the bulk of this wastewater is currently transported to the local farmers and used as fertilizer. Frequent long distance trips of large quantities of wastewater are costly and the farmers have only a limited need for the product. The environmental impact of the shipping is considerable. Electrocoagulation offers an elegant method for concentration of the sludge-based fertilizer separated from wastewater, thus significantly reducing the volume of material shipped to the farmers. Drastically reduced levels of pollutants in remaining wastewater make its disposal a lot less problematic. Phase 1 of the study took place in October 2013 and consisted of full-scale EC processing of centrifuged biogas reactor wastewater. Phase 2 was bench scale processing of non-centrifuged wastewater, in March 2017, concentrating on production of usable, more concentrated and easily transportable sludge. Phase 3 plans include investigating a larger number of biogas plants, focusing on specific plant nutrient uptake from various sludges, and eliminating nitrogen from the liquid phase.
1. INTRODUCTION In Norway, the annual organic sludge production is approximately 250,000 tons in addition to approximately 175,000 m3 of wet organic waste. About 3% of that material ends up in biogas production, with the aim of increasing that percentage. The management of wastewater resulting from the biogas production is not without challenges when the purpose is to recycle nutrients and avoid pollution. Hadeland and Ringerike Waste Management (HRA) is a Norwegian private company owned by 5 local communes, specialising in recycling and waste management of a wide range of material. A significant part of its business is receiving food waste from the local population and
Proceedings Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium/ 2 - 6 October 2017 S. Margherita di Pula, Cagliari, Italy / © 2017 by CISA Publisher, Italy
Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium / 2 - 6 October 2017
businesses and processing of this material in a biogas reactor. The process results in the annual production of about 10,000 m3 of wastewater from a decanter centrifuge that is used for recovering of solids from the final product of digestion. This wastewater is initially stored at HRA and then trucked to local farmers as soil conditioner and fertilizer. The large volume, however, is a problem – the transport is costly, required frequrently and therefore environmentally questionable. The farmers also have difficulties dealing with high volumes of this material. The cost of the sludge management and distribution could be significantly reduced if its volume were minimized without interfering with the quality of the product. In the past, usage of polymers by HRA in the attempt to improve the solids capturing in the decanter was not helpful. Electrocoagulation (EC), on the other hand, proved highly successful and provides a low cost alternative to traditional chemical methods of treatment and can make the centrifuge treatment redundant.
2. MATERIALS AND METHODS 2.1 Technology description Electrocoagulation (EC) is a relatively new technology that has been applied in various industries. The technology is extremely effective in achieving high removal levels of dissolved and suspended solids, dissolved metals, COD, BOD, FOG (fat, oil and grease), and other pollutants in wastewater streams from a range of industries such as abattoirs, oil industry operations, truck and tanker washing plants, general liquid waste facilities, and many other instances. Electrocoagulation is an ideal upstream pretreatment method of sophisticated filtration methods or reverse osmosis. A particular attraction of electrocoagulation is that the removal of contaminants can be achieved in a single step. The results are typically far superior to what can be achieved by chemical treatment. EC is also a viable alternative in situations where chemical coagulation simply fails. EC also achieves a high level of disinfection. The principle of the EC method is exposure of wastewater to direct current - wastewater stream passes through a reactor with anodes and cathodes. The electrodes delivering the electrical current are sacrificial – small amounts of electrode material are released and can provide seeding for sludge particles. The changes in the charges of particles and dissolved substances caused by the flood of electrons also contribute to the range of reactions taking place during the treatment, resulting in precipitation and coagulation of suspended, emulsified and dissolved contaminants. The EC Norway electrocoagulation system has a flowthrough reactor with vertically positioned electrodes. The wastewater is pumped into the reactor from the bottom, and the processed wastewater leaves from the top. The number and configuration of electrodes connected to the power supply of direct current depends on the conductivity of the processed material. The electrodes are made of aluminium and mild steel. Their number and their configuration within the reactor are selected depending on the characteristics of the wastewater. The level of current and voltage applied also depend on the quality of the wastewater treated. The system can operate relatively unattended providing the quality of the treated material is reasonably uniform and its conductivity does not vary significantly. The system is programmed to respond to interruptions in wastewater supply and other situations requiring attention.
Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium / 2 - 6 October 2017
Cleaning of the electrodes is conducted in several ways. The polarity of the electrodes is reversed periodically, and some of the reactors are equipped with an ultrasonic cleaning system designed specifically for the processing of produced water. Deposits developing within the reactor are removed by periodic pressured air scouring. Reactions continue after processed wastewater exits the reactor and passes to the separation unit (see Fig. 1). Particles of coagulated material attach to small gas bubbles produced by the electrolysis, and mostly temporarily float to the surface from where the material is skimmed. Denser sludge particles eventally settle and are removed from the bottom of the separator.
Figure 1 – Schematic flow sheet showing EC reactor followed by a separation tank. 2.2 EC Norway systems EC Norway AS constructed a mobile electrocoagulation pilot plant (Fig.2). The unit can handle up to 10 m3/h, but highly polluted wastewater is typically processed at the rate of only about 5 m3/hr. The entire system is operated automatically, housed in a modified 20 foot shipping container, together with the power supply, system operating panels, and a sludge separation unit. The container is heated and ventilated. The sludge separator has a dual function – the mainly floating sludge and oil is scraped off the surface of the separation tank (6 m3), while settled particles are removed from the bottom of the tank. Processed liquid is clarified within a lamella separator. Larger than 10 m3/h capacity electrocoagulation systems (up to 30 m3/h) have been installed in Australia by the EC Norway sister company EC Pacific Pty Ltd. They were mainly designed for treating wastewater from abattoirs and meat industry related rendering plants.
2.3 Electrocoagulation tests – HRA Initial test were performed in October 2013, using the mobile EC unit at the HRA premises
Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium / 2 - 6 October 2017
(Fig. 2). The tests were targeting sludge management within the settling ponds, the material treated was a mix of leachate coming from a disused landfill and liquid waste from the decanter centrifuge used to recover solids from the final product of the digested household food waste from the biogas production. The processing was very effective, with large quantities of sludge separated from the processed liquid. The sludge amount was exceptionally vast, as large amounts of dissolved material was coagulated as a result of the EC treatment and added to the solids already present in the raw, unprocessed wastewater. That was an excellent result, the treated wastewater after the sludge separation was very clear and the fertiliser fraction of the material – the sludge – easier to transport and handle.
Figure 2: Installation of the EC Norway mobile unit at the HRA premises, October 2013 Further tests were conducted by EC Norway in March 2017, concentrating on a slightly different material - processing HRA digester waste stream alone. The aim was again the reduction of the volumes of the material distributed to the farmers as fertiliser and purifying the water before it is realesed into the environment. The reduction of the fertiliser volumes takes place by coagulation of the suspended and dissolved material and separating the produced sludge from the treated wastewater. A laboratory scale EC unit was used by EC Norway at the laboratories of NIBIO, Norway.
Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium / 2 - 6 October 2017
Figure 3: Laboratory scale EC unit
The unit is – just as the large-scale EC systems – flowthrough. The wastewater is pumped through a reactor and is collected after the processing. The processed material is initially thick and foamy (Fig.4) and with time precipitates and settles. Gradually the coagulated sludge separates within the liquid, gravity dewaters (Fig. 5) and subsequently settles at the bottom of the container. In order to speed up this process and to maximize the clarification of the processed material, ferric chloride was used during the experiments, but when enough time and space available, that is typically not necessary.
Figure 4: Freshly processed material
Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium / 2 - 6 October 2017
Figure 5: Initial separation The coagulated sludge eventually settled and the clarified phase was decanted. Figure 6 shows the clarity of the final product achieved without filtration or any other separation means.
Figure 6: Clarity of gravity clarified processed wastewater
3. RESULTS AND DISCUSSION The results of our experiments are presented in Table 1 and show that the electrocoagulation treatment has a great potential in the management of the biogas wastewater treatment. The drastic volume reduction represents minimization of cost of the sludge transportation to the farmers. The discharge or further treatment of the clarified fraction also becomes less problematic, as the dissolved solids and nutrients are typically greatly reduced.
Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium / 2 - 6 October 2017
Table 1: Phoshorus and suspended solids removal rates resulting from the EC treatment
Parameter
Total Phosporus (mg/l) Suspended Solids (mg/l)
Average value raw biosolids wastewater 103
5,760
Average value EC treated liquid including sludge 101
14,300
Average value EC processed clarified liquid 0.05
66
Percentage removal (%) >99.9
>99.9
The results show an almost complete removal of both phosphorus and suspended from the material that was originally very concentrated. The suspended solids level increases significantly after the EC processing because a vast amount of originally dissolved material is converted into the suspended matter by the processing. The liquid is only gravity clarified. The percentages of removal rates are exceptional.
Figure 7: Concentration of suspended solids in raw wastewater, EC processed wastewater with sludge and EC treated wastewater (66 mg/l).
Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium / 2 - 6 October 2017
Figure 8: Concentration of total phosphorus in raw water, EC water and EC liquid. 4. CONCLUSIONS It has been demonstrated that electrocoagulation causes binding of most of the phosphorus and nitrogen species within the sludge, making the disposal of the clarified liquid logistically and environmentally a lot easier and less expensive. An important feature of electrocoagulation treatment is drastic reduction of dissolved solids as well as suspended solids in the processed wastewater. Since we are interested in the sludge usage, it is of great benefit that the amount of suspended solids in the processed material increases compared to the suspended soilds levels before the treatment, as the dissolved solids pulled out of the liquid and coagulated contribute to the suspended solids levels. It is a valuable source of prosphorus for field fertilisation. Electrocoagulation harvests the dissolved nutrients from the wastewater, increasing the amount of fertiliser and improving greatly the quality of the processed wastewater. The biogas producing industry in general has a definite need for its wastewater handling improvement. Electrocoagulation is assisting in making the fertiliser generation and distribution more practical and environmentally more beneficial, decresing the volumes transported. Electrocoaguation also disinfects, that making the produced fertiliser at least temporarily more stable from the biological point of view, controlling the potencial smell issues. Further studies have to be conducted and the methodology optimised. The next stage of the experiments should happen on the pilot scale level.
Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium / 2 - 6 October 2017
AKNOWLEDGEMENTS Many thanks to Hadeland and Ringerike Waste Management personnel, always keen to help in every way. Our thanks also go to the Norwegian Institute for Bioeconomy, NIBIO, for their interest, professional support and expertise. REFERENCES Alena Tetreault, “Electrocoagulation in Wastewater Treatment Case Studies from Australia”, IWA 3rd World Water Congress, Melbourne, Australia, 7-12 April 2002 Alena Tetreault, “Electrocoagulation in Wastewater Treatment-Case Studies from Australia”; ISWA World Environment Congress in Istanbul, Turkey, July 2002 Alena Tetreault, “Electrocoagulation in Treatment of Abattoir International Convention and Exhibition, Perth, WA, 6-10 April 2003
Wastewater”;
Ozwater
Alena Tetreault, “Electrocoagulation in Wastewater Treatment – New Technology Showcase”; Seventh International Symposium, Australian Renderers’ Association Inc, Surfers paradise, QLD, 16-18 July 2003 Alena Tetreault, “Electrocoagulation treatment of low temperature rendering plant wastewater – full-scale plant in an Australian abattoir”; EnviroNZ03, NZWWA International Conference, Auckland, New Zealand, September 2003 Alena Tetreault, “Use of Electrocoagulation In Meat Processing Plant”; Meat Processing Environment Forum, Brisbane, 21 April 2004Alena Tetreault, “Electrocoagulation in Treatment of Wastewater at an Australian Abattoir”; 2nd IWA Leading Edge Conference on Water and Wastewater Treatment Technologies, Prague, Czech Republic, 1-4 June 2004 (the paper published in a special IWA publication) Alena Tetreault, Peter Dold, Tore Øian, “Electrocoagulation Performance in Treatment of Slop Water and Other Wastewaters”, WEFTEC Conference, Chicago, USA, 5-9 October 2013
SUMMARY: The paper presents the results of electrocoagulation treatment of wastewater resulting from the biogas production generated at the Hadeland and Ringerike Waste Management (HRA) plant in Norway, performed by EC Norway AS, a Norwegian company working closely with the Australian company EC Pacific Pty Ltd. The biogas reactor wastewater is highly concentrated. In the absence of a suitable treatment or means of concentration the bulk of this wastewater is currently transported to the local farmers and used as fertilizer. Frequent long distance trips of large quantities of wastewater are costly and the farmers have only a limited need for the product. The environmental impact of the shipping is considerable. Electrocoagulation offers an elegant method for concentration of the sludge-based fertilizer separated from wastewater, thus significantly reducing the volume of material shipped to the farmers. Drastically reduced levels of pollutants in remaining wastewater make its disposal a lot less problematic. Phase 1 of the study took place in October 2013 and consisted of full-scale EC processing of centrifuged biogas reactor wastewater. Phase 2 was bench scale processing of non-centrifuged wastewater, in March 2017, concentrating on production of usable, more concentrated and easily transportable sludge. Phase 3 plans include investigating a larger number of biogas plants, focusing on specific plant nutrient uptake from various sludges, and eliminating nitrogen from the liquid phase.
1. INTRODUCTION In Norway, the annual organic sludge production is approximately 250,000 tons in addition to approximately 175,000 m3 of wet organic waste. About 3% of that material ends up in biogas production, with the aim of increasing that percentage. The management of wastewater resulting from the biogas production is not without challenges when the purpose is to recycle nutrients and avoid pollution. Hadeland and Ringerike Waste Management (HRA) is a Norwegian private company owned by 5 local communes, specialising in recycling and waste management of a wide range of material. A significant part of its business is receiving food waste from the local population and
Proceedings Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium/ 2 - 6 October 2017 S. Margherita di Pula, Cagliari, Italy / © 2017 by CISA Publisher, Italy
Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium / 2 - 6 October 2017
businesses and processing of this material in a biogas reactor. The process results in the annual production of about 10,000 m3 of wastewater from a decanter centrifuge that is used for recovering of solids from the final product of digestion. This wastewater is initially stored at HRA and then trucked to local farmers as soil conditioner and fertilizer. The large volume, however, is a problem – the transport is costly, required frequrently and therefore environmentally questionable. The farmers also have difficulties dealing with high volumes of this material. The cost of the sludge management and distribution could be significantly reduced if its volume were minimized without interfering with the quality of the product. In the past, usage of polymers by HRA in the attempt to improve the solids capturing in the decanter was not helpful. Electrocoagulation (EC), on the other hand, proved highly successful and provides a low cost alternative to traditional chemical methods of treatment and can make the centrifuge treatment redundant.
2. MATERIALS AND METHODS 2.1 Technology description Electrocoagulation (EC) is a relatively new technology that has been applied in various industries. The technology is extremely effective in achieving high removal levels of dissolved and suspended solids, dissolved metals, COD, BOD, FOG (fat, oil and grease), and other pollutants in wastewater streams from a range of industries such as abattoirs, oil industry operations, truck and tanker washing plants, general liquid waste facilities, and many other instances. Electrocoagulation is an ideal upstream pretreatment method of sophisticated filtration methods or reverse osmosis. A particular attraction of electrocoagulation is that the removal of contaminants can be achieved in a single step. The results are typically far superior to what can be achieved by chemical treatment. EC is also a viable alternative in situations where chemical coagulation simply fails. EC also achieves a high level of disinfection. The principle of the EC method is exposure of wastewater to direct current - wastewater stream passes through a reactor with anodes and cathodes. The electrodes delivering the electrical current are sacrificial – small amounts of electrode material are released and can provide seeding for sludge particles. The changes in the charges of particles and dissolved substances caused by the flood of electrons also contribute to the range of reactions taking place during the treatment, resulting in precipitation and coagulation of suspended, emulsified and dissolved contaminants. The EC Norway electrocoagulation system has a flowthrough reactor with vertically positioned electrodes. The wastewater is pumped into the reactor from the bottom, and the processed wastewater leaves from the top. The number and configuration of electrodes connected to the power supply of direct current depends on the conductivity of the processed material. The electrodes are made of aluminium and mild steel. Their number and their configuration within the reactor are selected depending on the characteristics of the wastewater. The level of current and voltage applied also depend on the quality of the wastewater treated. The system can operate relatively unattended providing the quality of the treated material is reasonably uniform and its conductivity does not vary significantly. The system is programmed to respond to interruptions in wastewater supply and other situations requiring attention.
Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium / 2 - 6 October 2017
Cleaning of the electrodes is conducted in several ways. The polarity of the electrodes is reversed periodically, and some of the reactors are equipped with an ultrasonic cleaning system designed specifically for the processing of produced water. Deposits developing within the reactor are removed by periodic pressured air scouring. Reactions continue after processed wastewater exits the reactor and passes to the separation unit (see Fig. 1). Particles of coagulated material attach to small gas bubbles produced by the electrolysis, and mostly temporarily float to the surface from where the material is skimmed. Denser sludge particles eventally settle and are removed from the bottom of the separator.
Figure 1 – Schematic flow sheet showing EC reactor followed by a separation tank. 2.2 EC Norway systems EC Norway AS constructed a mobile electrocoagulation pilot plant (Fig.2). The unit can handle up to 10 m3/h, but highly polluted wastewater is typically processed at the rate of only about 5 m3/hr. The entire system is operated automatically, housed in a modified 20 foot shipping container, together with the power supply, system operating panels, and a sludge separation unit. The container is heated and ventilated. The sludge separator has a dual function – the mainly floating sludge and oil is scraped off the surface of the separation tank (6 m3), while settled particles are removed from the bottom of the tank. Processed liquid is clarified within a lamella separator. Larger than 10 m3/h capacity electrocoagulation systems (up to 30 m3/h) have been installed in Australia by the EC Norway sister company EC Pacific Pty Ltd. They were mainly designed for treating wastewater from abattoirs and meat industry related rendering plants.
2.3 Electrocoagulation tests – HRA Initial test were performed in October 2013, using the mobile EC unit at the HRA premises
Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium / 2 - 6 October 2017
(Fig. 2). The tests were targeting sludge management within the settling ponds, the material treated was a mix of leachate coming from a disused landfill and liquid waste from the decanter centrifuge used to recover solids from the final product of the digested household food waste from the biogas production. The processing was very effective, with large quantities of sludge separated from the processed liquid. The sludge amount was exceptionally vast, as large amounts of dissolved material was coagulated as a result of the EC treatment and added to the solids already present in the raw, unprocessed wastewater. That was an excellent result, the treated wastewater after the sludge separation was very clear and the fertiliser fraction of the material – the sludge – easier to transport and handle.
Figure 2: Installation of the EC Norway mobile unit at the HRA premises, October 2013 Further tests were conducted by EC Norway in March 2017, concentrating on a slightly different material - processing HRA digester waste stream alone. The aim was again the reduction of the volumes of the material distributed to the farmers as fertiliser and purifying the water before it is realesed into the environment. The reduction of the fertiliser volumes takes place by coagulation of the suspended and dissolved material and separating the produced sludge from the treated wastewater. A laboratory scale EC unit was used by EC Norway at the laboratories of NIBIO, Norway.
Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium / 2 - 6 October 2017
Figure 3: Laboratory scale EC unit
The unit is – just as the large-scale EC systems – flowthrough. The wastewater is pumped through a reactor and is collected after the processing. The processed material is initially thick and foamy (Fig.4) and with time precipitates and settles. Gradually the coagulated sludge separates within the liquid, gravity dewaters (Fig. 5) and subsequently settles at the bottom of the container. In order to speed up this process and to maximize the clarification of the processed material, ferric chloride was used during the experiments, but when enough time and space available, that is typically not necessary.
Figure 4: Freshly processed material
Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium / 2 - 6 October 2017
Figure 5: Initial separation The coagulated sludge eventually settled and the clarified phase was decanted. Figure 6 shows the clarity of the final product achieved without filtration or any other separation means.
Figure 6: Clarity of gravity clarified processed wastewater
3. RESULTS AND DISCUSSION The results of our experiments are presented in Table 1 and show that the electrocoagulation treatment has a great potential in the management of the biogas wastewater treatment. The drastic volume reduction represents minimization of cost of the sludge transportation to the farmers. The discharge or further treatment of the clarified fraction also becomes less problematic, as the dissolved solids and nutrients are typically greatly reduced.
Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium / 2 - 6 October 2017
Table 1: Phoshorus and suspended solids removal rates resulting from the EC treatment
Parameter
Total Phosporus (mg/l) Suspended Solids (mg/l)
Average value raw biosolids wastewater 103
5,760
Average value EC treated liquid including sludge 101
14,300
Average value EC processed clarified liquid 0.05
66
Percentage removal (%) >99.9
>99.9
The results show an almost complete removal of both phosphorus and suspended from the material that was originally very concentrated. The suspended solids level increases significantly after the EC processing because a vast amount of originally dissolved material is converted into the suspended matter by the processing. The liquid is only gravity clarified. The percentages of removal rates are exceptional.
Figure 7: Concentration of suspended solids in raw wastewater, EC processed wastewater with sludge and EC treated wastewater (66 mg/l).
Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium / 2 - 6 October 2017
Figure 8: Concentration of total phosphorus in raw water, EC water and EC liquid. 4. CONCLUSIONS It has been demonstrated that electrocoagulation causes binding of most of the phosphorus and nitrogen species within the sludge, making the disposal of the clarified liquid logistically and environmentally a lot easier and less expensive. An important feature of electrocoagulation treatment is drastic reduction of dissolved solids as well as suspended solids in the processed wastewater. Since we are interested in the sludge usage, it is of great benefit that the amount of suspended solids in the processed material increases compared to the suspended soilds levels before the treatment, as the dissolved solids pulled out of the liquid and coagulated contribute to the suspended solids levels. It is a valuable source of prosphorus for field fertilisation. Electrocoagulation harvests the dissolved nutrients from the wastewater, increasing the amount of fertiliser and improving greatly the quality of the processed wastewater. The biogas producing industry in general has a definite need for its wastewater handling improvement. Electrocoagulation is assisting in making the fertiliser generation and distribution more practical and environmentally more beneficial, decresing the volumes transported. Electrocoaguation also disinfects, that making the produced fertiliser at least temporarily more stable from the biological point of view, controlling the potencial smell issues. Further studies have to be conducted and the methodology optimised. The next stage of the experiments should happen on the pilot scale level.
Sardinia 2017 / Sixteenth International Waste Management and Landfill Symposium / 2 - 6 October 2017
AKNOWLEDGEMENTS Many thanks to Hadeland and Ringerike Waste Management personnel, always keen to help in every way. Our thanks also go to the Norwegian Institute for Bioeconomy, NIBIO, for their interest, professional support and expertise. REFERENCES Alena Tetreault, “Electrocoagulation in Wastewater Treatment Case Studies from Australia”, IWA 3rd World Water Congress, Melbourne, Australia, 7-12 April 2002 Alena Tetreault, “Electrocoagulation in Wastewater Treatment-Case Studies from Australia”; ISWA World Environment Congress in Istanbul, Turkey, July 2002 Alena Tetreault, “Electrocoagulation in Treatment of Abattoir International Convention and Exhibition, Perth, WA, 6-10 April 2003
Wastewater”;
Ozwater
Alena Tetreault, “Electrocoagulation in Wastewater Treatment – New Technology Showcase”; Seventh International Symposium, Australian Renderers’ Association Inc, Surfers paradise, QLD, 16-18 July 2003 Alena Tetreault, “Electrocoagulation treatment of low temperature rendering plant wastewater – full-scale plant in an Australian abattoir”; EnviroNZ03, NZWWA International Conference, Auckland, New Zealand, September 2003 Alena Tetreault, “Use of Electrocoagulation In Meat Processing Plant”; Meat Processing Environment Forum, Brisbane, 21 April 2004Alena Tetreault, “Electrocoagulation in Treatment of Wastewater at an Australian Abattoir”; 2nd IWA Leading Edge Conference on Water and Wastewater Treatment Technologies, Prague, Czech Republic, 1-4 June 2004 (the paper published in a special IWA publication) Alena Tetreault, Peter Dold, Tore Øian, “Electrocoagulation Performance in Treatment of Slop Water and Other Wastewaters”, WEFTEC Conference, Chicago, USA, 5-9 October 2013
