Öresundsverket WWTP has with the installation of the Primozone ozone plant been able to reduce problems with filamentous sludge and at the same time increase capacityon water throughput.
At Öresundsverket WWTP in Helsingborg,Sweden, they have problems with filamentous sludge during springtime, as do many other activated sludge plants.With ozonation of the return sludge flow Öresundsverket has drastically reduced the amount of filamentous sludge and significantly increased the quality of the water – and this without any negative impact on the nitrification or thebiological phosphorus separation.
Ozone is a very strong oxidant and therefore avery good method for treating wastewater. In the treatment of sludge containing filaments the ozone breaks up the filaments and improves the settling characteristics of the sludge, without any negative effect on the important nitrification process.
To find out more about ozonation of filamentous bacteria and ozone’s impact on the other biological processes, NSVA chose to start with a pilot project. Öresundsverket’s activated sludge plant is optimally designed to run pilot tests as the cleaning process is divided into four completely separate treatment lines.
The pilot project gave clear results incomparison with the untreated lines. Sludge Volume Index was reduced dramatically,while the biological processes were not affected . Marinette Hagman, who is specialist in Development & Benchmarking at NSVA is very satisfied with the results.“In the line that was treated with ozone there is almost no foam or sludge on the surface compared with the untreated pools.Whether the problems in the digester are reduced, we cannot say anything about because sludge from all the lines is mixed before the reactor,” says Marinette Hagman. However it is reasonable to assume that these problems would disappear if all lines were treated.
Small and efficient
The Primozone SM900 is a complete ozone plant housed in a small container . At Öresundsverket the plant was complete with a dissolution system and a reaction tank. The container solution means that you do not need a new or existing building to install the plant. In addition, it can easily be placed close to the activated sludge process and even be moved to another facility.