Here we take a look at something a little different in our latest guest blog with Kevin Lindegaard, Director of the consultancy Crops for Energy Ltd and former director of the Wood Heat Association. Kevin shares with us the benefits of using a sustainable, natural water processing method, one that he hopes will become more commonplace in the future.
At Crops for Energy, you advocate the use of SRC willows as a sustainable, natural biofiltration system for water treatment. Can you tell us about how this works please?
Short Rotation Coppice (SRC) consists primarily of densely planted, high yielding varieties of willow that are harvested usually every three years.
The system of using SRC for water treatment, as opposed to a hard engineering technology, is based on the plants’ capability to uptake a large amount of water. It is estimated that SRC willows can use up to 0.4 million litres of water per tonne of dry matter produced per year. As a plot of willow should yield around 10 dry tonnes per hectare per year, that would mean approximately 4 million litres of water absorbed per hectare per year. That allows for approximately 10,000 litres of water to be applied to a 1 hectare SRC willow plot per day - making it the ideal way to recycle surplus waste water from an industrial process.
Each plot is designed using a regimented double row layout of planted willows, allowing irrigation pipes to be easily laid between the rows. Water is then pumped on to the plot, according to a pre-set irrigation regimen controlled by environmental stimuli such as soil temperature, moisture and importantly, rainfall. As a result, there is sometimes a need to store the wastewater until it can be applied; however, we will generally suggest a plot size that would be able to deal with either all, or part of, a facilities waste water production.
In many cases, SRC willow provides a much more affordable and greener way of recycling of a surplus of dirty water. The system has a wide range of applications, from municipal wastewater to wastewater from vegetable production or processing to landfill leachate and other contaminated liquids (subject to agreement with environmental bodies).
As long as the chemical concentrations in the water are not high enough to kill the crop, and N, P & K nutrient guidance is not exceeded, this system can be used. When an SRC willow plot is designed well, it can produce incredible yields and also provide a facility with an additional income from sale of the crop to power stations or biomass boilers.
Why should industrial facilities consider switching to methods like this in the future for processing wastewater?
As we all know, the treatment of wastewater costs money. If an industrial facility’s processes produce a significant amount of wastewater, management will inevitably be looking into ways to cut processing and treatment costs.
By using a solution like SRC willows, companies can look to reduce their water treatment costs significantly. While initial investment in a plot is required – establishing the crop, pipework, storage, pumps, controls and interfaces – the plot itself can be situated locally to the source of production, and in most cases, the investment made is paid back in under three years, depending on current waste water management costs. Once set up, the only costs are in operations and maintenance, as well as monitoring the irrigation rates.
Aside from cost savings, what other benefits are there to using a natural method like SRC?
The use of SRC willows is ideal for companies interested in making carbon savings. The lifecycle carbon emissions from a system like this is far less than a conventional engineered approach as it is less energy intensive. In addition, facilities will be contributing to renewable energy supplies and further reducing carbon emissions by generating biomass that can be substituted for fossil fuels.
Furthermore, this crop calls for far less machinery movement and fewer chemicals than conventional agriculture, leading to soil improvement. Birds, butterflies, and bees and many other insects will benefit from the crop. SRC willows can also be planted on land that is left vacant by farmers, perhaps because the land does not provide them with a strong source of income.
The use of SRC also generates usable biomass as a by-product, how can that benefit companies?
The biomass market is constantly increasing. In the UK, there are many biomass power stations and approximately 25,000 wood fuelled boilers. With the opportunity for potential buyers offering to purchase the harvested crop, the production of biomass could turn into a significant source of income for a company using SRC willows.
Facilities that already own a biomass boiler and have a wastewater problem are particularly suited to a biomass solution like SRC, enabling a reduction in cost in both areas.
Geopolitical changes in the world can cause all sorts of ramifications, but a facility that is producing all, or some of its own fuel will be far better placed to deal with this.
In the vast majority of situations, biomass is highly sustainable, provides rural jobs and income and provides a carbon lean fuel. We need more people to understand this so that biomass can take its place in the renewable energy mix.
Do you think utilising biomass could help the UK reach climate change targets if utilised effectively?
According to recent research by the Energy Technologies Institute, it suggests that planting an energy crop such as SRC on 1 to 1.8 million hectares could produce 6% of the UK’s energy requirement and reduce the cost of meeting the UK’s 2050 carbon reduction targets by more than 1% of GDP. This figure is more than the agriculture sector’s entire output of 0.7% of GDP (2014), indicating the major economic impact that bioenergy could provide.
While at VWT UK, we advocate technologies and services solutions, it is clear that SRC willow systems can provide a practical option for some, should this option fit a company’s wastewater needs and the land required to plant the crops is available.
If that’s not the case, at VWT UK we have a number of solutions that can help companies reduce their wastewater treatment costs and increase a plant’s sustainability credentials. Our Hubgrade digital monitoring solution, for example, provides real-time performance optimisation of a wastewater treatment facility allowing plants to increase operational productivity while cutting costs, energy consumption and potential waste.
For more information on Short Rotation Coppice and Crops for Energy, please click here.
For more information on VWT UK’s Hubgrade digital monitoring services offering, please click here.
About the Author
Kevin has been involved in biomass energy for nearly 25 years originally as a plant breeder of fast growing and high yielding willows. For the last 15 years he has been one of the countries’ leading consultants on biomass and energy crops. He is a former director of the Wood Heat Association and a co-founder of the Sustainable Fuel Register.