Improving biosolids management has been key in maximizing the true potential of using biosolids for plant growth. Given the large volumes of sewer water that treatment plants receive from towns and cities around the world, improving biosolids management to sustainably replace chemical fertilizers is more important than ever.
Scientists worldwide have poured their efforts into formulating the right mix of ingredients that could be incorporated into biosolids to give it the best quality and quantity of nutrients that would stimulate plant growth.
One study investigated blending biosolids with common urban wastes like food, yard litter, sawdust and nut shells. What they discovered was that the mixture produced acceptable outcomes that addressed a couple of biosolids’ well known issues such as smell and appearance. The new additives also contributed to better plant growth.
Ryan Batjiaka, a researcher from the University of Washington, has a keen interest in improving biosolids management and sees the benefits of using soil additives with biosolids. He believes that the use of organic matter with sewer water by-products creates a viable alternative to traditional fertilizers because the latter is finite and more expensive to procure.
He cited the use of phosphorus as an example. This nutrient is extracted from rock phosphate which is usually derived from mining. Nitrogen is synthetically produced in a process that takes up 3-5% of the world’s gas production.
“When we use biosolids and urban residuals to create topsoil or soil additions, we are not extracting these finite resources. Instead, we are recycling nutrients that flow through the systems we manage,” says Batjiaka. He indicated that topsoils can also gain from this alternative organic mixture because importing virgin topsoil is a costly and temporary solution for rehabilitating denuded lands.
Batjiaka knows that there is a negative stigma that the community has when it comes to municipal waste. He believes that scientific and objective information can provide clarity on the value of this practical resource.
Improving biosolids management ensures that biosolids produced at the treatment plants are subjected to rigorous processing to guarantee their safety. They are also subjected to the most stringent standards set forth by the Environmental Protection Agency before they can be made commercially available.
Another way of improving biosolids management that experts are looking into is biochar. This is a product of carefully burned plant material so that it retains high concentrations of carbon. This is added along with lumber waste and sand before being blended into the biosolids.
They tested these enhanced biosolids by planting cucumber, radish and petunia seeds to see how it affected their germination and plant growth performance. They also surveyed volunteers to assess the smell and appearance of the biosolids mixture.
As expected, plant growth improved with the use of biosolids blended with organic compounds, particularly from the one which incorporated yard waste. When it came to the smell and looks, volunteers were more in favor of the biosolids mixed with wood waste as it gave the least offensive odour and more acceptable appearance.
Batjiaka explains that the results made perfect sense since the wood waste helped reduce ammonia, which stifles plant growth and is the source of offensive odours.
Batjiaka is encouraged by the outcome of his study and is optimistic that recovering sewer wastes can be a sustainable endeavour that could directly address critical environmental threats that are prevalent today.
If you are a farmer in the Niagara Region and are interested in considering biosolids as a potential application to your fields, please contact us at 1 (877) 479-1388. There is no cost for us to apply to the MOE or to spread biosolids on your field. These costs are covered by the Region of Niagara.