Major projects

SUE "Vodokanal of St. Petersburg" is implementing the following major projects:

The Neva Untreated Wastewater Discharge Closure Program

This program envisages, among other things, the completion of the extension of the Northern Tunnel Collector, and the modernization of the Northern and Central Wastewater Treatment Plants to comply with new requirements of HELCOM (the Baltic Marine Environment Protection Commission) regarding enhanced removal of nitrogen and phosphorus from wastewater.

 

The program is financed from the municipal and federal budgets, own funds of SUE “Vodokanal of St. Petersburg” and raised extra-budgetary funds. 

The project of the construction of the Northern Tunnel Collector was approved in 1989 by the order of the Council of Ministers of RSFSR. The city's demand for a new, a 12 km long section of the Tunnel Collector was dictated by the need for transportation of wastewater from residential houses and industries of Primorskiy, Kalininskiy, Krasnogvardeyskiy, partially Nevskiy and Central districts to the Northern WWTP in Olgino. Originally, the NTC extension construction was planned for ten years. However, from 1993 to 2000 the construction was suspended due to the lack of financing. In 2001, allocation of funds from the St. Petersburg budget began aiming to maintain the construction works, but those funds were not enough for the planned large-scale works. In 2005, a new stage of the collector construction began. The first line of the NTC extension was put into operation in autumn 2008. It enabled us to channel direct wastewater discharges in the amount of 90,000 cubic meters per day to the sewage system and reach the level of 88% of wastewater treatment. Further connection of direct wastewater discharges to the NTC allowed to reach the level of 91% wastewater treatment by the end of 2009, 93% - by the end of 2010, 94% - by autumn 2011, 97% - by December 2012, 98.4% - since October 2013, 98.5% - since April 2015. 

The extension of the NTC is a system of very complex engineering facilities: two lines of main tunnels with length of 12.2 km each and external diameter of 4 m each laid at a depth of 40-90 m; dozens of inlet and distribution chambers; many kilometers of connecting micro-tunnels. Besides, the NTC includes a unique facility – wastewater pumping station; it is a high-capacity pumping facility which regulates velocity of the wastewater stream through the collector to prevent silting.

The completion of the NTC has ensured treatment of 98.4% of wastewater since October 10, 2013.

 After that Vodokanal will have to eliminate direct wastewater discharges in the area of the Okhta River and the Karpovka River. Our company plans also to reconstruct wastewater treatment plants in the town of Kolpino and Pontonny settlement.

In December 2014, Vodokanal of St. Petersburg closed nine direct discharges of the Petrovsky Stadium which were the source of thousands cubic meters of untreated wastewater per day coming to the Neva River. Direct wastewater discharges along Petrogradskaya Embankment were closed in the end of 2014, along Admiralteyskaya Embankment and the Fontanka River Embankment  – in 2015.

The important stage of the Neva Untreated Wastewater Discharge Closure Program – the construction of the sewage collector along the part of Admiralteyskaya Embankment from Dvortsovy Proezd to the Senatskaya Square was completed in April 2015. It made it possible to close six untreated wastewater discharges, equivalent to approx. 1,000 m3/day, into the Neva. Alongside with the completion of works at the Senatskaya Square, construction of the sewage network at the Repina Square was started. New sewage network enabled to close the direct discharge to the Fontanka River in Lotsmanskaya Street and to channel wastewater for treatment to the Central Wastewater Treatment Plant.

In 2016, works on the construction of the Okhta Tunnel Sewer Collector were intensely carried out. The construction of the Okhta Tunnel Sewer Collector is one of the key measures to stop the discharge of untreated sewage. The construction of the Okhta Tunnel Collector will allow stopping the discharge of wastewater without treatment into the Okhta River and will provide the opportunity for the development of housing estate in St. Petersburg and the Leningrad Region. In addition, in 2016, within the framework of the program to stop the discharge of surface wastewater into water bodies in order to reduce the negative impact on the environment, works on the project for “Reconstruction of rain sewage as part of the program for landscaping the Murinsky Park” were carried out. 

Totally, 44 direct wastewater discharges were closed from 2016 till 2018. 

In the beginning of December 2019, SUE “Vodokanal of St.Petersburg” achieved a 99% treatment of household sewage received by the centralized combined wastewater disposal system.

  • Modernization of the city water treatment plants

In 2010, the construction of a new 350,000 m3/day water treatment block K-6 was completed at the Southern WTP. In early 2011, the supply of water from the new block to the customers began.

The distinctive features of the technological solution used in the design and construction of K-6 block are as follows:

  • preliminary ozonization of water with small ozone doses to ensure surface oxidation of humic compounds and improvement of their further coagulation,
  • precipitation of the coagulated water in the lamellar clarifier for more effective removal of suspended solids compared to traditional sedimentation tanks,
  • filtration of water on dual-bed filters with granular activated carbon and quartz sand for better removal of dissolved organic matter, including oil products.

The flush water produced at K-6 Block is treated with the release of sludge, which is disposed separately to prevent the Neva water contamination.

All water treated at K6 Block is disinfected with sodium hypochlorite and ammonium sulfate, then by UV-radiation.

In the coming years, new water treatment blocks will be built at the Northern Water Treatment Plant (800,000 cubic meters per day) and at the Main Water Treatment Plant (500,000 cubic meters per day).

  • Creation of water supply management system

In 2010, the construction of a new 350,000 m3/day water treatment block K-6 was completed at the Southern WTP. In early 2011, the new block started to supply water to customers.

 The distinctive features of the technological solution used in the design and construction of K-6 block are as follows:

  • preliminary ozonization of water with small ozone doses to ensure surface oxidation of humic compounds and improvement of their further coagulation,
  • precipitation of the coagulated water in the lamellar clarifier for more effective removal of suspended solids compared to traditional sedimentation tanks,
  • filtration of water on dual-bed filters with granular activated carbon and quartz sand for better removal of dissolved organic matter, including oil products.

 The flush water produced at K-6 Block is treated with the release of sludge, which is disposed separately to prevent the Neva water contamination. 

All water treated at K6 Block is disinfected with sodium hypochlorite and ammonium sulfate, and then by UV-radiation.

 In the coming years, new water treatment blocks will be built at the Northern Water Treatment Plant (800,000 cubic meters per day) and at the Main Water Treatment Plant (500,000 cubic meters per day).

  • Improvement of sewage sludge treatment and disposal technologies

Today, all the sludge produced by wastewater treatment is burnt at three sludge incineration plants. However, in the previous years (before the incinerators were constructed) sludge was disposed to special landfills. For instance, the area of Severny landfill in Novoselky is about 83 ha. 

To eliminate a negative impact of sewage sludge landfills on the environment, a landfill reclamation project was designed on the basis of Geotube technology. 

With this technology, special geotubes (filtration geotextile containers) are used where sludge is treated with chemicals. As a result, sludge is disinfected, dewatered and stabilized; odor is removed, too. A harmless, odor-free substance is produced, which can be used for preparation of artificial soils. 

In 2010, Vodokanal began the reclamation works at Severny landfill. Today, the company is confronted with the task to treat sludge, which has been accumulated up to 2007, and ensure its environmentally safe condition.

 Vodokanal carries out pre-design studies for the reclamation of the Severny landfill, which form the basis for the development of the terms of reference for the project. Implementation of this project will eliminate the negative impact of the landfill on the environment. A set of works for preparing landfill storage beds for reclamation, including the determination and justification of the optimal technology for processing sewage sludge to an ecologically safe state, will be developed under the project.

According to the results of the production tests and technical-and-economic assessments, the company has selected and used the technology of geotubing (sludge treatment with reagents and static dewatering in geotextile bags). The product formed by geotubing is absolutely safe. This has been confirmed by an independent expertise. Sewage sludge is treated with a special reagent for converting active forms of heavy metals into bound ones. As a result of a full-scale processing, a safe, odorless substrate is formed, which can be used as the basis for the production of technical soil. Reconstruction of the sludge bed no.7 (the nearest to residential developments and WHSD), including the processing of sewage sludge to an ecologically safe state, is to be completed by 2020.