OREANDA-NEWS. October 3, 2012. Vodokanal St. Petersburg has launched the odour control pilot project at Severny landfill in Novoselky town where wastewater sludge is stockpiled.

Severny landfill to stockpile wastewater sludge with the area of 83 ha was put into operation in 1986 together with the commissioning of the Northern Wastewater Treatment Plant.

The result of wastewater treatment is treated effluent (it is transported into the Gulf of Finland), but at the same time sludge is produced that includes the waste derived from wastewater during a treatment process. From the plant commissioning till 2008, the sludge produced at the Northern Wastewater Treatment Plant was transported to Severny landfill. In 2008, the Sludge Incineration Plant at NWWTP began its operation in full (it was constructed in 2007) and transportation of sludge to the landfill stopped.

Today, all the sludge produced after wastewater treatment in Saint Petersburg is incinerated at plants (there are three such plants in our city, including that one at the Northern Wastewater Treatment Plant). But in the time preceding the commissioning of NWWTP SIP, about 2 Mio m3 of sludge was accumulated at Severny landfill.

Vodokanal is solving this task in two ways: global (in order to fully eliminate the adverse impact of the landfill on the environment in future) and local (in order to remove odours at the landfill today). The implementation of the sludge treatment program will allow to fully eliminate the adverse impact of the landfill on the environment. This project is based on the geotube technology (geotubes are special sacks where sludge is treated with different chemicals). As a result of such treatment a safe odourless substrate is produced, which can be used for technogenic soil production (for example, for bedding of railway embankments).

By the beginning of 2012, 12% of the total volume of stockpiled sludge had been treated using the geotube technology. It is expected to complete this project at Severny landfill by 2017. As a result, a significant part of the landfill area will be released. It is assumed, in particular, to arrange green spaces in this area. In parallel, Vodokanal considered different technologies that make it possible to remove odour “here and now” (the odour situation became more acute after cutting down forests in process of development of adjacent to the landfill areas, as the forests used to prevent the spread of odour). As a result, in September 2012 the automated deodorant spray complex was launched as a pilot project.

This complex consists of a pumping station with a control unit and a main 300 m long located on posts (at the height of 6 m above the ground) around the landfill perimeter. This main covers the landfill part facing the ring road. Spayers are placed along the main with the interval of 6 m, through which fine-dispersed deodorant solution is sprayed. This solution is a mixture of essential oils and organic compounds of plant origin. It does not substitutes the unpleasant odour but destroys it. The solution applied is non-toxic and environmentally safe.

However, pay attention that Severny landfill is not the only possible source of unpleasant odour. Next to it there is a city solid waste landfill (city dump).