Pure and simple
28 Nov 2006
Effluent discharge control is becoming an increasing challenge for companies in the process industries.
Meeting increasing demands for higher water quality in production processes and ever-stricter regulation with regard to effluent discharge control is becoming an increasing challenge for companies in the process industries.
For many operations, the best approach is to examine their basic requirements before starting down the road of selecting and investing in any of the many physical, chemical and biological treatment technologies on the market.
The target for most process engineers should be to establish their water usage in the first place, said Stuart Ballinger, a spokesman for Envirowise - an agency that offers UK businesses free support on practical ways to minimise waste and environmental impact.
"It's the old adage, if you don't measure, you can't manage," said Ballinger. "Before you can begin to reduce the amount of water your business consumes, you need to understand where water is being used within the business."
Envirowise focuses first on helping companies establish their actual water usage and highlights easy ways to reduce water use. Since its launch last year, its experts helped 150 companies save around 2 million cubic metres of water.
The agency recommends a number of support tools such as the "Mogden Formula", which calculates the charges water companies apply to industry for the conveyance and treatment of effluents discharged to sewer. The Microsoft Excel-based tool allows users to apply data to investigate the impact of modifying specific aspects of the effluent on the cost to discharge.
For example, explains Ballinger, "flow, COD (chemical oxygen demand) and suspended solids can all be modified independently to investigate whether a preliminary treatment system may be a cost-effective option to consider."
Another area is disposal to sewer. This, said Ballinger, is an expensive options so "companies need to be sure of the regulatory requirements they need to meet and talk to sewage companies about what they actually need to do to discharge straight to sewerage systems."
When it comes to investing in new water treatment technologies, meanwhile, process engineers face an increasingly complex task in selecting the optimum system for their particular operational requirements. The pace of technology improvement is accelerating — often tailored to the requirements of each particular industry as well, of course, as regulatory requirements.
One positive factor here is the increasing affordability of water treatment technology — helped in part by the recent extension of the Government's Enhanced Capital Allowance (ECA) scheme to include many water saving devices.
Under the ECA, businesses can now claim 100% first-year capital allowances on investments in technologies and products that encourage sustainable water use. The official ECA 'Water Technology List' includes; cleaning-in-place equipment, flow controllers, leakage detection equipment; meters and monitoring equipment and efficient membrane filtration systems.
Cambridgeshire food manufacturer G's Fresh Beetroot this year became the first company to gain ECA approval for tax relief on a membrane filtration system. The company manages the entire food manufacturing process from growing produce through to production and marketing.
G's engaged Aquabio Ltd of Worcester to design a membrane filtration system to treat its process water to allow for on-site re-use. The system had to meet the ECA eligibility criteria, which includes a requirement that it allows for at least 40% of the treated effluent to be used on site.
Investment incentive
According to the company, it was able to claim first-year allowances of around £120,000 under the scheme, which shortened the payback period by 12 months to under 2.5 years. The Aquabio membrane filtration system allows it to treat, recover and re-use up to 70% of the wastewater generated on-site and so cut water supply and disposal costs by around £125,000 a year.
ECA eligibility "really made the difference" by providing G's with a major incentive to invest, said Graham Forber, managing director of the company.
"Not only will we be able to significantly reduce our water and effluent costs, but the ECA has also shortened the payback period of the project, giving the board the confidence to invest," Forber commented.
When it comes to selecting the best technology for any particular plant, Ballinger urges companies to look across the full range of options. "They need to speak directly to equipment suppliers and look for examples of applications in their area to see best case practices in their sector."
Suppliers are now much more responsive to the needs of the customer and the kit is going to do what it's supposed to do, continued Ballinger. "Gone are the days when anaerobic systems were sold into companies that didn't work too well."
Membrane technologies such as microfiltration, ultrafiltration and reverse osmosis feature strongly in most water treatment applications. Further cleanup of water for recycling is likely to require microfiltration (MF) or ultrafiltration (UF) membranes, followed by nanofiltation (NF) and/or reverse osmosis (RO) at the end of the treatment process.
"Companies that require high purity, such as pharmaceutical and semiconductor may also add electrodeionisation. While RO will remove 90-98% of dissolved solids ion exchange or electrodeionisation will reduce dissolved solids to a couple of ppm, explains German industry group Decema.
Membrane technologies
Equipment suppliers such as Dow, GE Infrastrucure, Koch Membrane Systems and Siemens are working to increase the spread of many membrane technologies, which were once only considered for specialist niche applications. For example, 90% of' (KMS) pilot studies now feature UF/RO technologies, compared to 10% just five years ago, said a Dechema report.
The latest membranes are designed to reduce energy consumption and give better rejection of dissolved solids.
For example, KMS' latest hollow fibre products for water treatment contain 60% more membrane area and provide 60% more product water than predecessor cartridges. Likewise, the same company's largest RO element has over seven times the membrane area of a traditional RO element, which also allows more compact and less costly installations.
"The membrane industry is working hard to develop products and processes that achieve the required technical performance at an acceptable price for all sectors of the water treatment industry," said Ian Elson is senior vice president and general manager Europe of KMS.
"The market requirement for lower cost options for water treatment has resulted in the development of membrane modules with increased membrane area and consequently the capability to treat larger volumes of water or wastewater. In particular, UF hollow fibre membrane cartridges and RO membrane elements have increased in size," said Elson.
Biological treatment systems are also making significant inroads, particularly in the food & beverage industry, where the latest fixed film systems deliver both highly effective waste treatment and energy recovery.
The Norrmejerier Dairy in Umea, Sweden, for example, recently opted to install a Biomar anaerobic fixed film reactor from Enviro-Chemie GmbH — in part because of its energy recovery requirements.
At the dairy, organic contents of the dairy's wastewater as well as whey and whey permeate are acidified, hydrolyzed and conditioned to create a suitable environment for the aerobic treatment.
Treatment takes place in two methane reactors, where acetic acids are turned into biogas, which the dairy uses as a source of energy. The dairy produces 8000 cubic metres of biogas daily, which is used to generate steam and hence decreases the dairy's fuel costs.
"This way we not only save primary energy resources, we also save Euro2500/day," said Olof Wallin manager of the dairy, who also points to several other advantages including a significant reduction in waste disposal costs as the process generates hardly any sludge.
The COD value of the wastewater is decreased by 60-90% in the methane reactors so the water can then be fed into public waterways. To feed the treated water directly into rivers and lakes it needs to be even cleaner, which is why aerobic treatment is the last step in the process.
In the US, meanwhile, CoolBrands — one of the world's largest producers of ice cream and yogurt — has partnered with Ecovation to change the way it disposes of the waste byproducts from yogurt and cottage cheese production.
In August 2005, the dairy product major signed a contract with Ecovation for the installation of its anaerobic waste treatment and renewable energy production technology at a North Lawrence, New York facility, which process over 180 million pounds of milk a year.
The $3.3-million project is expected to produce enough biogas to replace nearly 250,000 gallons of fuel oil each year, nearly 25% of the plant's total usage that is consumed to generate steam for the production process
Ecovatio claims its Mobilized Film Technology (MFT) is the most efficient system available for removing organic material from high strength wastewater. Treatment involves an immobilisation process that uses small inert particles upon which bacteria can attach in a thin film to produce a high density of microorganisms to generate large amounts of biogas.
The MFT hydraulic control system regulates the upflow velocity of the wastewater to match the biomass settling rate and optimise digestion between the organics in the wastewater and the attached biomass. This, claims Ecovation, results in the lowest possible effluent concentrations of sludge and unused solid waste.
For many operations, the best approach is to examine their basic requirements before starting down the road of selecting and investing in any of the many physical, chemical and biological treatment technologies on the market.
The target for most process engineers should be to establish their water usage in the first place, said Stuart Ballinger, a spokesman for Envirowise - an agency that offers UK businesses free support on practical ways to minimise waste and environmental impact.
"It's the old adage, if you don't measure, you can't manage," said Ballinger. "Before you can begin to reduce the amount of water your business consumes, you need to understand where water is being used within the business."
Envirowise focuses first on helping companies establish their actual water usage and highlights easy ways to reduce water use. Since its launch last year, its experts helped 150 companies save around 2 million cubic metres of water.
The agency recommends a number of support tools such as the "Mogden Formula", which calculates the charges water companies apply to industry for the conveyance and treatment of effluents discharged to sewer. The Microsoft Excel-based tool allows users to apply data to investigate the impact of modifying specific aspects of the effluent on the cost to discharge.
For example, explains Ballinger, "flow, COD (chemical oxygen demand) and suspended solids can all be modified independently to investigate whether a preliminary treatment system may be a cost-effective option to consider."
Another area is disposal to sewer. This, said Ballinger, is an expensive options so "companies need to be sure of the regulatory requirements they need to meet and talk to sewage companies about what they actually need to do to discharge straight to sewerage systems."
When it comes to investing in new water treatment technologies, meanwhile, process engineers face an increasingly complex task in selecting the optimum system for their particular operational requirements. The pace of technology improvement is accelerating — often tailored to the requirements of each particular industry as well, of course, as regulatory requirements.
One positive factor here is the increasing affordability of water treatment technology — helped in part by the recent extension of the Government's Enhanced Capital Allowance (ECA) scheme to include many water saving devices.
Under the ECA, businesses can now claim 100% first-year capital allowances on investments in technologies and products that encourage sustainable water use. The official ECA 'Water Technology List' includes; cleaning-in-place equipment, flow controllers, leakage detection equipment; meters and monitoring equipment and efficient membrane filtration systems.
Cambridgeshire food manufacturer G's Fresh Beetroot this year became the first company to gain ECA approval for tax relief on a membrane filtration system. The company manages the entire food manufacturing process from growing produce through to production and marketing.
G's engaged Aquabio Ltd of Worcester to design a membrane filtration system to treat its process water to allow for on-site re-use. The system had to meet the ECA eligibility criteria, which includes a requirement that it allows for at least 40% of the treated effluent to be used on site.
Investment incentive
According to the company, it was able to claim first-year allowances of around £120,000 under the scheme, which shortened the payback period by 12 months to under 2.5 years. The Aquabio membrane filtration system allows it to treat, recover and re-use up to 70% of the wastewater generated on-site and so cut water supply and disposal costs by around £125,000 a year.
ECA eligibility "really made the difference" by providing G's with a major incentive to invest, said Graham Forber, managing director of the company.
"Not only will we be able to significantly reduce our water and effluent costs, but the ECA has also shortened the payback period of the project, giving the board the confidence to invest," Forber commented.
When it comes to selecting the best technology for any particular plant, Ballinger urges companies to look across the full range of options. "They need to speak directly to equipment suppliers and look for examples of applications in their area to see best case practices in their sector."
Suppliers are now much more responsive to the needs of the customer and the kit is going to do what it's supposed to do, continued Ballinger. "Gone are the days when anaerobic systems were sold into companies that didn't work too well."
Membrane technologies such as microfiltration, ultrafiltration and reverse osmosis feature strongly in most water treatment applications. Further cleanup of water for recycling is likely to require microfiltration (MF) or ultrafiltration (UF) membranes, followed by nanofiltation (NF) and/or reverse osmosis (RO) at the end of the treatment process.
"Companies that require high purity, such as pharmaceutical and semiconductor may also add electrodeionisation. While RO will remove 90-98% of dissolved solids ion exchange or electrodeionisation will reduce dissolved solids to a couple of ppm, explains German industry group Decema.
Membrane technologies
Equipment suppliers such as Dow, GE Infrastrucure, Koch Membrane Systems and Siemens are working to increase the spread of many membrane technologies, which were once only considered for specialist niche applications. For example, 90% of' (KMS) pilot studies now feature UF/RO technologies, compared to 10% just five years ago, said a Dechema report.
The latest membranes are designed to reduce energy consumption and give better rejection of dissolved solids.
For example, KMS' latest hollow fibre products for water treatment contain 60% more membrane area and provide 60% more product water than predecessor cartridges. Likewise, the same company's largest RO element has over seven times the membrane area of a traditional RO element, which also allows more compact and less costly installations.
"The membrane industry is working hard to develop products and processes that achieve the required technical performance at an acceptable price for all sectors of the water treatment industry," said Ian Elson is senior vice president and general manager Europe of KMS.
"The market requirement for lower cost options for water treatment has resulted in the development of membrane modules with increased membrane area and consequently the capability to treat larger volumes of water or wastewater. In particular, UF hollow fibre membrane cartridges and RO membrane elements have increased in size," said Elson.
Biological treatment systems are also making significant inroads, particularly in the food & beverage industry, where the latest fixed film systems deliver both highly effective waste treatment and energy recovery.
The Norrmejerier Dairy in Umea, Sweden, for example, recently opted to install a Biomar anaerobic fixed film reactor from Enviro-Chemie GmbH — in part because of its energy recovery requirements.
At the dairy, organic contents of the dairy's wastewater as well as whey and whey permeate are acidified, hydrolyzed and conditioned to create a suitable environment for the aerobic treatment.
Treatment takes place in two methane reactors, where acetic acids are turned into biogas, which the dairy uses as a source of energy. The dairy produces 8000 cubic metres of biogas daily, which is used to generate steam and hence decreases the dairy's fuel costs.
"This way we not only save primary energy resources, we also save Euro2500/day," said Olof Wallin manager of the dairy, who also points to several other advantages including a significant reduction in waste disposal costs as the process generates hardly any sludge.
The COD value of the wastewater is decreased by 60-90% in the methane reactors so the water can then be fed into public waterways. To feed the treated water directly into rivers and lakes it needs to be even cleaner, which is why aerobic treatment is the last step in the process.
In the US, meanwhile, CoolBrands — one of the world's largest producers of ice cream and yogurt — has partnered with Ecovation to change the way it disposes of the waste byproducts from yogurt and cottage cheese production.
In August 2005, the dairy product major signed a contract with Ecovation for the installation of its anaerobic waste treatment and renewable energy production technology at a North Lawrence, New York facility, which process over 180 million pounds of milk a year.
The $3.3-million project is expected to produce enough biogas to replace nearly 250,000 gallons of fuel oil each year, nearly 25% of the plant's total usage that is consumed to generate steam for the production process
Ecovatio claims its Mobilized Film Technology (MFT) is the most efficient system available for removing organic material from high strength wastewater. Treatment involves an immobilisation process that uses small inert particles upon which bacteria can attach in a thin film to produce a high density of microorganisms to generate large amounts of biogas.
The MFT hydraulic control system regulates the upflow velocity of the wastewater to match the biomass settling rate and optimise digestion between the organics in the wastewater and the attached biomass. This, claims Ecovation, results in the lowest possible effluent concentrations of sludge and unused solid waste.
