Fig. 1. Many large water processing sites include facilities that process solid waste and recover energy from it.
Wear protection is key to continuous production and optimised whole life costs in sludge-energy-from waste plants.
Entscheidend für eine ausfallfreie Produktion und für optimierte Lebensdauerkosten von Anlagen zur
Energiegewinnung aus der Schlamm- und Müllentsorgung ist der Verschleißschutz.
La protection contre l’usure est un élément essentiel pour une production continue et des coûts de cycle de vie optimisés dans les procédés d’énergie tirée des boues de stations d’épuration.
Protecting process plants against wear and tear
S
ewage sludge from wastewater has long been viewed as an expensive nuisance, fit only for treatment and disposal. However, new regulations as to its disposal, preventing dumping at
sea or in landfill, have forced a major rethink. As a result, Utilities are increasingly using technologies designed to help extract energy and other valuable products from wastewater sludge. This development makes sound economic as well as environmental
sense.Sewage contains 10 times the amount of energy needed to treat it; and it is technically feasible to recover energy from sludge.
Renewable energy source As a renewable energy source, it can be used directly in wastewater treatment, reducing a facility’s dependency on conventional electricity, or as a fossil fuel substitute supplying the power utility cement and mineral processing industries with a secondary
fuel source in lieu of coal, to reduce emissions of greenhouse gases. Using solids as a resource, rather than a waste,
may help stressed public budgets as well. However, as with any energy from waste (EFW) operation, there are costs involved. Wastewater solids must be processed prior to disposal, and solids handling accounts for as much as 30 per cent of a wastewater treatment facility’s costs. As with all forms of energy, continuity of
supply is paramount. This means that the plants that process sewage sludge into pellets or granulate are continuous operations that cannot stop for adhoc repairs and refurbishment. Militating against achieving 24/7 operation is the nature of the sludge itself. On its passage through sewers, sewage becomes contaminated with flood debris, sand, grit, deposits from environmental structures, residue from the land mass, plus metallics, and plastics. Sand and grit, in particular, are a major problem,
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