Articles & Case Studies

Integrated waste treatment solution from Neutralac

Posted: Wednesday 31st July 2013

In a time when both economic and environmental issues are fast becoming high on agendas for many companies, in terms of industrial applications, it is encouraging that one utility company is taking considerable strides in this direction.

The main issues centred on the treatment of raw sewerage that would enable the resultant, treated waste water to be safely recycled and for the remaining slurry be suitable and safe as a farm fertiliser.

In the past, waste sludge has been in danger of being insufficiently cleansed and disinfected, with the potential of retaining pathogens such as Campylobacter and Salmonella, which can cause food poisoning, contaminating the soil. This renders it inadequate as a fertiliser and therefore only suitable for landfill – a commercially and environmentally negative solution.

One solution is to use large gas powered drum driers which although effective are costly to run and expensive to maintain, a position this utility company found itself in. Therefore, after decommissioning the drying equipment, with unsustainably high running costs, an alternative method for disinfecting and dewatering the sludge had to be found.

Traditionally, wastewater and slurry is separated using centrifugal technology to de-water the slurry. However, it was found that by pre-treating the waste with Neutralac® SLS45 before de-watering, its high alkaline content sufficiently neutralises the wastewater so it can be recycled back into the water course, and the slurry is cleansed and disinfected for use as farm fertiliser. The organic matter is enhanced for farming purposes due to the lowering of acidity, the removal of pathogens and subsequent high nitrate qualities.

The chemical reaction of high strength liquid lime creates a sterile alkaline environment in excess of pH12 for sustained periods, effectively disinfecting the sludge by killing the wide spectrum of pathogens listed above.

Furthermore, the cost reductions in transporting both the treated water and disinfected slurry become significant while, at the same time, closing the environmental recycling loop. The disinfected farm slurry also offers an income stream previously not always available to utilities companies as it can then be sold to farmers.

A spokesperson for the utility company commented: ‘We have been through a stringent process and our selection of Neutralac® SLS45 was not taken lightly. Our tests have shown a significant improvement in the lowering of acidity of waste, and the improvement and relevance of the resultant slurry as a fertiliser.’

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August 2021

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