Sludge disposal can be simple but expensive, sludge isn’t acceptable at landfill and therefore should be dealt with like water which usually comes with a significant increase in disposal cost compared to landfill.

If you want to save money and minimise waste then there are several solutions for turning sludge into a solid suitable for landfill (or possibly for re-use on site) which may be worth considering. The right solution for you will depend largely upon available space and time, factored with volumes and anticipated cost benefits of de-watering the sludge.

From a construction site perspective the cheapest option is likely to be a basic settlement system such as a storage lagoon. Storage in a lagoon will give most types of sludge a chance to dry or separate out (weather permitting).

Systems which are more advanced than lagoons will provide the required improvements faster and to a higher spec (e.g. lower water content). These come in many forms including-

• Geo-textile dewatering
• Mechanical dewatering –centrifuge or filterpress
• Cement / lime solidification

Cost is at the root of all sludge management, low volumes typically lead to low tech solutions (e.g. settlement lagoon) or simply off-site disposal. Large volumes, or on-going sludge production, can mean that more high tech solutions become financially viable.

It is also possible to re-incorporate sludge by mixing with a suitable dry material on site. If you are considering this approach then make sure you’re not mixing contaminated materials with non-contaminated materials, and also be aware of mixing in too much sludge which would end up with just a higher volume of a slightly more viscous sludge being produced.

As always please do not hesitate to get in contact if you have any queries on 0800 0209 307 or info@soilutions.co.uk

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