Innovation

The Thermal Hydrolysis engine originally started off as a university project and was then developed by the Norwegian firm Cambi. Due to a successful small-scale pilot in Norway, many of these plants were constructed and successfully implemented throughout the country. The success in Norway has resulted in water treatment facilities in China, North America, South America and European countries slowly following suit and developing the innovation.

Veolia worked in partnership with Scottish Water on the construction of the Thermal Hydrolysis engine, taking over 2.5 years to construct. The construction process used a large workforce, with a variety of different specialisms to complete the project.

“The use of that electricity allows us to be broadly around 95% self-efficient. So, we are not having to buy in a whole lot of energy… this is absolutely vital. Another factor of cake which is quite unique to this process. Once upon a time this was a waste product and it would have to go to a landfill, but because it’s being treated to a certain standard we can actually put this stuff onto agricultural land. So, it went within the past 7 years from being a waste product that we had to pay for people to take and put in their landfills to a product that we are now able to sell.”

Veolia operates Seafield on behalf of Scottish Water and have a contract which means there are certain revenue streams that they can pursue. Thermal Hydrolysis provides Veolia with a way to make and save money through removing electricity bills, reducing landfill costs and selling the ‘cake’ fertilizer to farmers.

Inspiration

Thermal Hydrolysis was developed to increase the efficiency of biogas production and compliant ‘cake’ at the facility, in order to reduce electricity and landfill costs. This would allow the company to be self-sufficient and create another source of income through selling the compliant cake to farmers as fertilizer and land rejuvenation projects.

In addition to the looking for ways to improve biogas production and cake quality, Veolia is always looking for ways to develop the circular economy- which is the core of its business model. This involves looking at waste as a resource, which is what the business believes we need to do to ensure that we operate sustainably. It is also important for the public’s perception of waste water treatment to be changed and it was hoped that creating useable products from this process might help that.

Whether this was changing the local community’s perception of the company by getting them more involved and aware of what they do, or offering a new approach or method to farmers through the use of natural fertilisers rather than chemical substances, Veolia “are striving for innovation and looking at new ways to make things better. We try to be good neighbours”.

The purpose of the innovation is to be self-sustainable through the use of biogas which can be converted into electricity and heat.

“The use of that electricity allows us to be broadly around 95% self-efficient”

Furthermore, the organic waste produced using thermal hydrolysis allows for a rich natural and better quality ‘cake’ fertiliser which can then be sold to farmers to be used on agricultural land as a rich natural fertiliser.

“It’s being treated to a certain standard we can actually put this stuff onto agricultural land.”

Overall impact

Thanks to the Thermal-Hydrolysis process, Veolia can be proud of having a 100% positive impact on the 3 pillars of the sustainable development by being economically efficient, environment-friendly and socially fair.

Besides generating profit, it allows the company to save a considerable amount of money which would be spent in buying energy to power the plant. Instead, the TH process enables the company to produce green energy to be almost completely self-efficient and to be exported into the national grid when there is surplus - powering local homes and business.

The TH process not only leads to the production of biogas for energy and electricity, it also makes possible the production of 100 tons a day of clean and biological fertiliser. This can be used by local farmers for boosting their crops and regenerating their lands, making them more environmentally friendly. It also leads to the reduction of scarce resource extraction and its reuse in the life-cycle, instead of being put to landfill, is a major advancement toward the transformation of the linear economy into a circular one.

Seafield manages 850,000 peoples worth of waste every day. The TH process enables Veolia to place minimal demand on the national grid, which is better for local communities and the environment as there is less demand on fossil fuels whilst also reducing the amount of odorous gases released into the atmosphere which can affect local people. It is also beneficial for local farmers by allowing them to be more cost-efficient producers. Veolia is still working on engaging with the public in the local community to raise people’s awareness; the overall impact on society is hugely positive.

Business benefit

The Thermal Hydrolysis (TH) engine brings various business benefits to the organisation. Since the implementation of the system in 2015, Veolia has improved their ability to produce their own energy, increasing the power they generate from 55% of production needs, to 95% by enhancing the renewable energy they create. This is achieved through the sludge mix going through anaerobic digestion which creates biogas that fires up a combined heat and power (CHP) plant.

Most days, there are periods where Seafield is self-sufficient, using no electricity from the Grid. Without the TH, Veolia would yield a lot less useable bio gas. This processor increases their gas production by 30%.

“30% more gas which means 30% more energy production which means 30% less to spend on electricity so on and so forth it”.

The advancements have resulted in the Seafield site reducing their energy costs by 50%. This new process has the ability to achieve greater sustainability standards in the industry using waste water as an energy source. This would also help the industry meet their carbon reduction targets.

“Veolia can make a significant contribution towards delivering renewable energy targets, while keeping the lights on and taking pressure from the National Grid.”

Until TH was implemented, Veolia sent a lot more waste to landfill. Indeed, in addition to the “screenings or rags”, they also had to send sludge, which is now transformed and reused. Therefore, with the introduction of TH, costs to land fill have significantly reduced, saving Veolia millions per year. Additionally, as the waste product is treated to a certain standard with the TH engine, you can add it onto agricultural land. This has resulted in an additional income for the company.

“All the stuff that comes out of the filter process, called screenings or rags, have to go to landfill because they have no value in them”

“If all that sludge was coming to go to a landfill we would end up losing millions and I think, before Veolia took over the contract and before this process was installed, a lot of the sludge was failing its consent and was having to go to landfills. So, it was costing a lot of money.”

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Social and environmental benefit

Social benefits

The innovation also produces some social benefits. The ‘cake’ can be used by agricultural farmers as fertiliser for farmer’s crops. “You could take that straight to land and put it on crops”. This benefits both the company and farmers but also the whole society as it only costs £2.50 a tonne for rich fertiliser that is just as good, which is highly regarded by farmers as they are not using additional chemicals that might be regarded as harmful. This shows how the TH is delivering social value.

Environmental Benefits

The implementation of the thermal hydrolysis has resulted in numerous environmental benefits. One environmental benefit is that the creation of green electricity reduces the need to use external means of producing electricity, like gas power stations, which causes air pollution. The process also reduces the need for farmers to use chemically enhanced fertilisers that damage the environment and cause land pollution.

Overall, the process transforms the sludge into two new resources, benefitting the environment by becoming a part of the cycle of life.

Interview

James Walker, Sludge Engineer