Using the material choking Russian lakes for sustainable water technologies

The poor environmental practices of the former Soviet Union and other eastern European states over many decades iswell documented.While these were most glaring for industrial plants and mines, they also spread to agriculture.

One of the lesser-known disasters came from a lack of systems thinking in irrigation. To create vast new areas of irrigated agriculture, the wetlands around lakes were drained to providewaterfor newly created farms. The unintended consequence was that where water, carrying oxygen, used to flow from the surrounding wetlands into the lake , now the net flow was directed away from the lake.

Lakebeds became desperately short of oxygen, while nutrients, probably from fertiliser runoff, were plentiful at the surface, leading to algae growth. Algae and other organic matter have a high biological oxygen demand and these large blooms further depleted the oxygen content of the lake. The jelly-like material on these eastern European lakebeds is known as sapropel (from the Greeksaprosandpelos, meaning putrefaction and mud, respectively), and there is a lot of it.

Sapropel, though very rich in organic material such as algae, humic acid, and some living bacteria, is mostly waterand, luckily, can be easily pumped out. Removal of sapropel helps restore the lake to a place where many species can live. The challenge, however, is to find a use for it.

Romanian billionaire Dinu Patriciuhas suggested using it as fuel, and this may yet prove to be commercially viable. But removing the large quantities of water takes energy; the challenge is to work out how to produce more energy than is consumed in retrieving the sapropel from the lakebed.

Another, and very different, approach is being taken byZander Corporation, a Lancaster-based company. Zander has developed two classes of products from sapropel, which they call AgriZan and ClearEarth. These address several very important needs.

Tests by Zander, and engineers atStopford Engineering, have shown that ClearEarth has strong binding properties for heavy metals, such as cadmium, lead and mercury. Industrial waste water contaminated with these metals, or water leaching from waste dumps, can be cleansed by flowing through ClearEarth. Further experiments have demonstrated that ClearEarth is a good bioremediation medium (using biological organisms to solve environmenal problems) for soils contaminated with hydrocarbons such as diesel or motor oil. Bioremediation is well established and regulated across Europe for such applications, and a new, effective material is likely to find a ready market.

Equally interesting is the application of AgriZan to improve efficiency of delivering water and nutrients to seeds and young plants. When seeds are growing, they demand water from their surroundings. Even very efficient drip irrigation systems waste water, and most conventional irrigated agriculture is worse, mainly because water is provided whether the plant needs it or not. With a material like sapropel, the water is bound as if in a sponge, and is provided to the plant when it needs it. Nutrients are similarly held and provided on demand. Tests on this material show that its effectiveness in soil seems to last over a very long period, several growing seasons.

It is through this sort of systems thinking - turning the unintended consequences of Soviet agricultural practice into an opportunity for efficient agriculture, wastewater treatment, and bioremediation, while restoring lakes to health - that good science enables environmental sustainability to move forward.

Bernie Bulkin is a director of Ludgate Investments and of HMN Colmworth. He was chair of the Office of Renewable Energy for the UK government from 2010-2013, and a member of the UK Sustainable Development Commission. He was formerly chief scientist of BP.

The water hub is funded by SABMiller. All content is editorially independent except for pieces labelled advertisement feature.

Source: The Guardian

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