Envotherms wastewater treatment plant helps Karup Air Base save an annual cost of DKK 1.1 million and reduces the consumption of water, energy and transportation. Now, Envotherm is facing the possibility of exporting their wastewater solution to an English air base. Envotherm has developed a technology that purifies contaminated water through evaporation. The distilled water is subsequently so clean, it can be reused for industrial processes - or discharged as ordinary wastewater. By using Envotherm’s wastewater treatment plant, customers are able to comply with limit values for emissions and avoid disposing of the contaminated water as hazardous waste. The evaporation technology cleans the water for a third of the cost of other solutions.
Envotherm is working hard to market their solution towards public customers, and selling of a plant to Karup Air Base marked the first sale to a public institution. It proved to be a good reference in the further efforts to enter into the public market. Envotherm uses Karup Air Base as a ”show case” for new clients and employees as the airfield praise the plant when public purchasers inquire. A second plant has already been sold as a direct consequence of a successful demonstration at the air base.
One of the most interesting effects of the sale to Karup Air Base is that an English airbase has shown Envotherm considerable attention. The English airbase has become aware of the benefits gained by Karup, and they have initiated a clarification process that will show whether the English airbase will repeat Karup’s successful experience. This could create opportunities for Envotherm on the English export market.
Financial advantage by solving a major environmental challenge
Each year, Karup Air Base discharges large amounts of wastewater from washing military equipment. The wastewater used to be discharged into the municipal wastewater system until analyses of water samples showed that the wastewater was polluted with cadmium beyond the permissible limits.
'We were requested by Viborg Municipality yo comply with wastewater limits, and when we analyzed the water samples, we became aware that the wastewater contained cadmium from the washing of helicopters', says Michael Damkjer, environmental officer at Karup Air Base.
The immediate solution was to transport the wastewater by tank truck to the municipal waste treatment facility – an expensive and time-consuming option. Karup assessed different technologies as alternative solutions. However, none of them met the requirements of the air base. Solutions where chemicals are used to make pollutants settle are harmful to the environment as well as health and safety. Electrolysis-based technologies could not remove enough cadmium to make the wastewater comply with the limit values. Only one solution fit the strict requirements of the air base; a plant from Envotherm, which was both the most environmentally friendly and economically advantageous option.
Before we invested in the plant from Envotherm, we were collecting the wastewater and shipping it to a hazardous waste treatment plant via the waste treatment facilities in Viborg. The costs were DKK 2 per liter for the treatment alone, and one helicopter generates 2,000-3,000 liters of wastewater. This corresponded to an annual cost of about DKK 1.1 million. On top of this was the costs of transportation, says Michael Damkjer.
The initial costs for Envotherms solution were DKK 2.2 million, and the annual operating costs are around DKK 48,000. Compared to the previous annual cost of DKK 1.1 million, the Envotherm solution was clearly advantageous. The investment has a repayment period of just over two years.
The costs connected to the purchase of a storage tank for dirty water, a destillat tank for clean water, and the construction of a small building for the plant, are included in the calculations. The Envotherm plant is not completely silent, so it was decided to move it to an extension in order for the employees not to be bothered.
Cost savings by focusing on operation expenses rather than the purchasing cost alone
Envotherm recommends that public procurement officers apply a long-term economic view on their procurement instead of focusing on the purchasing price or the budget of a single year. Envotherm experiences scepticism from public procurers and potential customers regarding the magnitude of the initial investment, when considering purchasing the Envotherm waste-water plant. It will be beneficial to show them the full financial picture from life-cycle costing, where it becomes clear that the system helps save money.
'We spend a lot of time and resources on informing about life-cycle costs, because it is not present in the mindset of the customers', says Vibeke Svendsen, CEO of Envotherm. 'Our plants typically have a payback time of 2-4 years and a lifespan of 12-15 years, so already after the 1st or 2nd year our solution turns into an income.'
The Danish Military – the head procurement organization for Karup Air Base – focuses on life-cycle costs. All investments with a payback period of less than 5 years must be implemented.
Solution spares the environment at least 123 tonnes of CO2 per year
The wastewater treatment plant achieves a total saving of 123 tonnes of CO2 per year when compared to letting the hazardous waste treatment facility handle the polluted water. This calculation does not include the energy consumption of the plant or the CO2 savings achieved by the significantly reduced truck transportation of wastewater. Before Karup Air Base bought the plant from Envotherm, the employees from the air base had to transport the wastewater from the helicopter wash to Viborg 15-18 times a year. This is now reduced to four annual trips to deliver the concentrate for waste treatment.
With the introduction of Envotherms wastewater treatment plant, the emission of cadmium has decreased by approximately 4.4 kg per year.
Envotherm is not the only system on the market that makes use of evaporation techniques, but their solution is very energy efficient. Envotherm can evaporate under atmospheric pressure instead of vacuum, which is the usual procedure. Along with a number of other energy-saving measures this reduces energy consumption from 836 kWh to 15-30 kWh/m3 depending on the type of wastewater.
The effective process is based on a special heat exchanger that the wastewater passes. The heat exchanger causes the water to evaporate on the liquid surface rather than on the metal surface, which is more efficient. This ensures that the precipitations are not on the heating surfaces and provides a constant heat transfer to evaporation. The evaporator recycles energy from the steam generated so that only 1-2 percent of the energy - that would otherwise be used to evaporate the water - is used.
Short description of Envotherm
Envotherm is a small company that has developed a resource efficient technology to treat and reuse wastewater. Richard Dines Schmidt, chemical engineer and technical director, and Vibeke Svendsen, MSc. and CEO, founded Envotherm in 2006. Vækst Fonden became co-owner in 2008 when the fund invested a total of DKK 8 million in the company.
In the past 3 years, Envotherm has tripled its turnover. The company has a profit ratio of approx. 9 percent. Envotherms goal is to become a global leader in the management of hazardous waste with evaporation technology.
Envotherm received EU’s environmental award in 2012 for one of their other environmentally friendly products, a system for car washing that reduces the water consumption from 150 liters to 3 liters per car wash.
The company is located in Nordborg, Denmark
Number of employees: 8-10
This case study originally appeared in a publication by the Danish Ministry of the Environment: 'Business cases for green procurement'