Hi-tech wastewater plant proposed in Snells Beach

The new treatment plant will be a significant upgrade from the oxidation ponds currently used to treat sewage in Snells Beach.

Watercare environment and consents manager Mark Bourne says the existing treatment plant relies on bacteria and sunlight to treat sewage, by storing it in large oxidation ponds. The solids and liquids slowly separate in the ponds and the process takes several days.

The new plant will be far more controlled and efficient by controlling the amount of sewage and oxygen in a series of enclosed tanks to give the perfect environment for micro-organisms to treat the wastewater.

Any foul odors from the treatment will be captured in the process and treated, so there will be no smell.

“It gives us much more control and only takes about 12 hours to treat it and gives a much higher quality end result.”

 

The footprint of the facilities will also be far smaller.

“The proposed treatment plant will be much more like a commercial and industrial processing plant.”

The sewage is then filtered through a fine membrane which removes all remaining material and the water is finally put through a UV treatment.

The treated wastewater is then stored in a large holding pond and piped to the Martins Bay discharge site on an out-going tide.

All of the solids that have been removed through the process are compressed and put into a commercial landfill.

 

“It is mixed with other landfill material. Because it is highly decomposable it assists in helping other matter decompose and generates methane. That methane is then captured and used to generate electricity which is sold back to the grid.”

By contrast, the solids from the existing Snells treatment plant sit at the bottom of the oxidation ponds and the sludge is removed about once every 10 years.

Mr Bourne says the proposed plant will cost a lot more to operate as it is far more intensive, but the environmental gains from superior treatment are worth it.