Why Are There Heavy Metals In Sewage Sludge?

Heavy metals are naturally occurring elements found within the Earth’s crust. They are incredibly difficult to remove from an environment as they cannot be degraded or destroyed. Heavy metals are commonplace – we even consume small amounts of zinc, copper and other heavy metals in our diet and need them to function.

However, heavy metals are an issue when they accumulate in large concentrations, such as in sewage sludge. But why are there heavy metals in sewage sludge in the first place? This article aims to look at various different heavy metals, how they make their way into sewage sludge and their associated risks.

The dangers of heavy metals in sewage sludge

Heavy metals are problematic when they enter water supplies because they bioaccumulate. This means that there has been an increase in the total amount of a specific heavy metal in an area in comparison to the environment. Heavy metals can accumulate in living organisms when they use food sources that contain them.

Heavy metals generally enter a water supply and sewage sludge through industrial and consumer waste byproducts. Although rarer these days, heavy metals could also enter sewage sludge via acid rain. The acid rain would break down soil components, freeing up heavy metals to enter streams, groundwater and other bodies of water.


Sewage SludgeAntinomy is a heavy metal that is found in antimony trioxide, which is commercially used as a flame retardant. It is commonly used in batteries, ceramics and glass. It is highly toxic and exposure – even for a short period of time – can result in nausea, vomiting and other ailments.


Cadmium is a heavy metal that is similar to zinc, which is an essential nutrient for many animals including us. However, cadmium is bio-persistent, so when it is absorbed by humans it stays in their system for decades. It is a heavy metal that is used to make batteries and cadmium coated products are corrosion-resistant. It is also present in fertilizers and petroleum.


Copper is an important heavy metal that is beneficial to humans in small doses, but in higher concentrations, it can cause all kinds of problems ranging from liver damage to intestinal problems. Copper is most commonly found in pipes and wiring around homes.

Eco-Septic is a Sydney based manufacturer and specialises in commercial wastewater systems of various shapes and designs. We can provide fast and free quotes relevant to your commercial wastewater treatment and sewage treatment needs, all while keeping in mind individual spending capabilities.

Contact us today for a fast quote at 1800 808 135 or visit us at www.ecoseptic.com.au.

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