Smithton STP sludge removal

TasWater is taking steps to address odour issues at Smithton Sewage Treatment Plant (STP) with the removal of thousands of tonnes of anaerobic sludge.

The sewage lagoons at Smithton were commissioned approximately 30 years ago but haven't been fully de-sludged during that time. It is the build-up of sludge, particularly in the first of the six lagoons, that is causing the odour issues.

TasWater identified the cause of the odour problem earlier this year and has now allocated the necessary funds to rectify the problem and provide a long-term fix.

Basically, an accumulation of the anaerobic sludge in the sewage lagoons means the treatment plant is operating at a significantly reduced capacity. The first lagoon is so full it has been taken completely off-line.

To address the odour problem in the short-term, TasWater has used recycled effluent to create a water cap over the sludge in the first lagoon.

To address the problem in the long-term, TasWater will remove sludge from the three worst-affected lagoons.

The sludge removal works will commence in late September 2017 and will be undertaken by Conhur Pty Ltd. Once completed, TasWater will be able to defer any further major capital expenditure on the Smithton STP for at least 15 years while we develop a long-term sewerage strategy for the Smithon region.

Most of the extracted sludge will either be transported off-site as liquid or de-watered and spread on local agricultural land as bio-solids. Some of the sludge will remain on-site for drying in the sludge drying beds.

Residents can be assured that the sludge will be removed, handled and transported in a safe, timely and environmentally-responsible manner.

Given the distance of the STP from nearby homes, noise is unlikely to be an issue during the sludge removal process. However residents can expect a significant increase in the number of heavy vehicles travelling to and from the STP site.

Residents may also notice an increase in odours while the sludge removal work is carried out. This is likekly to be the case particularly during the first two months of the project while the sludge is removed fronm the first lagoon. This lagoon has been off-line since earlier this year and is the major source of odours from the Smithton site. Recycled effluent has been used in recent months to maintain a water cap over the sludge and to minimise the risk of any further odour issues.

Conhur will commence with the removal of sludge to the on-site drying pans. Land spreading of sludge will take place during the dry period (November to March). Works are sxcheduled to be completed by the end of March 2018.


TasWater is taking steps to address odour issues at Smithton Sewage Treatment Plant (STP) with the removal of thousands of tonnes of anaerobic sludge.

The sewage lagoons at Smithton were commissioned approximately 30 years ago but haven't been fully de-sludged during that time. It is the build-up of sludge, particularly in the first of the six lagoons, that is causing the odour issues.

TasWater identified the cause of the odour problem earlier this year and has now allocated the necessary funds to rectify the problem and provide a long-term fix.

Basically, an accumulation of the anaerobic sludge in the sewage lagoons means the treatment plant is operating at a significantly reduced capacity. The first lagoon is so full it has been taken completely off-line.

To address the odour problem in the short-term, TasWater has used recycled effluent to create a water cap over the sludge in the first lagoon.

To address the problem in the long-term, TasWater will remove sludge from the three worst-affected lagoons.

The sludge removal works will commence in late September 2017 and will be undertaken by Conhur Pty Ltd. Once completed, TasWater will be able to defer any further major capital expenditure on the Smithton STP for at least 15 years while we develop a long-term sewerage strategy for the Smithon region.

Most of the extracted sludge will either be transported off-site as liquid or de-watered and spread on local agricultural land as bio-solids. Some of the sludge will remain on-site for drying in the sludge drying beds.

Residents can be assured that the sludge will be removed, handled and transported in a safe, timely and environmentally-responsible manner.

Given the distance of the STP from nearby homes, noise is unlikely to be an issue during the sludge removal process. However residents can expect a significant increase in the number of heavy vehicles travelling to and from the STP site.

Residents may also notice an increase in odours while the sludge removal work is carried out. This is likekly to be the case particularly during the first two months of the project while the sludge is removed fronm the first lagoon. This lagoon has been off-line since earlier this year and is the major source of odours from the Smithton site. Recycled effluent has been used in recent months to maintain a water cap over the sludge and to minimise the risk of any further odour issues.

Conhur will commence with the removal of sludge to the on-site drying pans. Land spreading of sludge will take place during the dry period (November to March). Works are sxcheduled to be completed by the end of March 2018.


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