Organo Mineral Fertilizer

We're developing the 'know-how' to convert sewage sludge into a range of commercial fertilizer products. The end result could be a more sustainable alternative to the conventional, off-the-shelf chemical fertilizers currently favoured by farmers.

How does it work?

Although many farmers in our area use the sludge cake produced by our sewage treatment process on their land, issues remain. Although dry in appearance, sludge cake is actually about 75 per cent water.With its high water content, the cake is bulky and costs a lot to transport to our farmers. We also know that it doesn't add as many nutrients to land as a chemical fertilizer would, although it is an excellent soil conditioner.

However, our Organo Mineral Fertilizer programme could make our sludge output significantly more attractive to agriculture. Key to this process is a granulator - a type of vacuum drier that gets rid of moisture. Using recycled steam, it produces granules which are compact, easily stored and, most importantly, don't take up as much space. It also means a significant move away from using power-hungry conventional driers. The next step, once we have our new granules, is the addition of organic mineral fertilizers in varying concentrations to produce a wide range of bespoke fertilizers that farmers would be keen on.

As well as the reduced energy costs described above, global supplies of the phosphorous needed to make conventional chemical fertilizers are in decline, so Organo Mineral Fertilizer could help here. Overall, it offers a sustainable, ecologically positive alternative that future generations could take advantage of.

Who's behind it?

Sidath Gedara from Sri Lanka is working for United Utilities on a Knowledge Transfer Partnership with Cranfield University. He studied agriculture in his home country before completing an MSc in Environment and Development from Reading University.