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Reducing surplus sludge in wastewater treatment



The EU-funded WASTEred project has facilitated the successful market launch of an eco-innovative product to reduce sludge generated during wastewater treatment in the food sector.

Over 25 million tonnes of sludge is generated during wastewater treatment in the meat and dairy sectors in the EU every year. This not only presents a serious environmental hazard but also results in considerable additional treatment costs for the businesses concerned.

To address this problem, Spanish company BIOAZUL teamed up with partners from across Europe in the WASTEred project to test the application of LODOred. This eco-innovative product is designed for use in aerobic wastewater treatment plants, where it helps to improve the efficiency of microbiological metabolism and so reduce the amount of sludge produced – see BOX.

The two-year project, part-funded by the EU CIP Eco-Innovation programme, has included 11 demonstration studies at meat and dairy plants in Germany, Poland and Spain. During these studies, an average reduction in sludge of between 10 and 50% has been achieved.

This has provided significant economic benefits for the plants, with sludge- disposals costs reduced by an average of 30% and energy costs by around 25%. Further savings in pollution charges and in the cost of polymers for dewatering of sludge are also being achieved. “Plants using LODOred are saving between two and three euro for every euro spent on the product,” explains project coordinator Antonia Lorenzo. “This represents an important cost saving, in addition to the many environmental benefits.”

LODOred is helping to reduce the ecological footprint of the entire wastewater treatment process. By cutting the amount of sludge produced, it helps improve the quality of receiving water bodies – lakes and rivers – with an estimated 20% reduction in phosphate and nitrogen pollution from the plants.

It also helps to cut air pollution, by reducing the demand for transport and so CO2 emissions and the amount of sewage sludge treated by incineration – cutting nitrogen oxides. On average, a 25% reduction in the use of chemical polymers was also achieved.

The WASTEred project is due to finish in October 2011, when full results will be available.

More information

Related information on the EcoAP Website

Micro-membrane bioreactors

When added to a biological treatment process, LODOred enwraps microorganisms, leading to the formation of compact activated sludge flocs. These flocs have a highly selective membrane coating, which enables manipulation of the metabolism inside. LODOred acts by inducing a change in microbial metabolism and in particular in the catabolic/anabolic balance: organic matter degradation or catabolism is promoted by a mixture of vitamins and enzyme stabilisers, while new cell biosynthesis or anabolism is slowed by other substances. Bacteria therefore become more efficient at removing the incoming BOD load, and less new biomass is generated as fewer bacteria are required to remove the same BOD load.