A major by-product of coal fuelled electricity generation is ash – fly ash and bottom ash. Bottom ash is collected from the bottom of the boilers while fly ash is an inert mineral matter collected in dust collection plant. There is currently a modest market for fly ash reuse as a cement replacement up to 30% by volume as well as in road construction and other uses. Delta continually reviews opportunities to recycle fly ash.
At Vales Point Power Station, ash is transported by wet sluicing to the ash dam. In a contract arrangement, ash is collected from the outlet of the fabric filter hoppers and transported to an onsite facility where it is processed for sale. The excess is then wet sluiced to the ash dam.
Bottom ash is collected at the ash dam from the wet sluice stream for processing and sale. Cenospheres, (minute floating particles) found in the ash dam, are also harvested and processed for sale. The Vales Point ash dam is divided into separate ponds and as each pond reaches capacity, it is capped and revegetated.
Continuous monitoring and rigorous environmental management programs are designed to minimise the impacts of ash storage at all Delta locations