Major environmental project completed in Petersburg


On Thursday, 10 October 2013, the 155th anniversary of Vodokanal St. Petersburg, the big environmental project, Northern Tunnel Collector Construction, was completed in Petersburg. Since that day, as much as 98.4 % of wastewater has been discharged treated in Petersburg.

It would not be possible to stop untreated wastewater discharge into the city’s water bodies without the construction of collectors. It is collectors that receive sewage from residential houses, offices, kindergartens, schools, hospitals and industries and then deliver it to wastewater treatment plants.  

But for the collectors, wastewater would be discharged directly to water bodies even with wastewater treatment plants in place.

The construction of Northern Tunnel Collector extended over several decades.

The first part of Northern Tunnel Collector, from Northern Wastewater Treatment Plant to Kantemirovskaya st., was built in 1987. At the same time, works began on the second Collector section – between Kantemirovskaya st. and the Finlyandskiy Bridge (the name of the project was “the Northern Tunnel Collector Extension”).

However, the works were suspended soon for financial reasons. It was only in XXI century that the construction of the Northern Tunnel Collector Extension was resumed. The works have been completed by 10 October 2013.

The completion of the Collector Project was marked by several events that happened on 10 October:

- the main tunnel’s second line was put into operation,

- pre-commissioning of the unique facility (a high-capacity pumping station designed to maintain stable operation of the Collector) began,

- by this date the remaining ten direct discharges (one on Vyborgskaya Embankment, six – on Robespierre Embankment and three discharges of flush water from the Main Water Supply  Plant) totaling 87,000 m3/day of wastewater were closed. Formerly, this wastewater was drained directly into the Neva, and now it flows through the Collector to Northern WWTP where it undergoes a full treatment cycle.

Notably, the Northern Tunnel Collector Project was completed in the year that was announced “the Environmental Protection Year” in Russia. Moreover, the 155th anniversary of Vodokanal St. Petersburg falls on 10 October 2013.

The Northern Tunnel Collector Extension is a complex system of engineering facilities.

It consists of:

  • two 4m diameter tunnels, 12.2 km each, laid at the depth of 40-90m;
  • 8 microtunnels, total length - 7,600km;
  • 64 shafts, 6-9m diameter each, at the depth of 10-80m;
  • 5.2 km of street sewerage networks, 0.25-1.2m in diameter;
  • sewage pumping station – a high-capacity pumping station installed in a 90m deep, 24 m diameter shaft.

With the Collector in place, 76 direct wastewater discharges could be closed and 334,000 m3/day of untreated wastewater were no longer drained into the Neva. It means nearly 22 million cubic meters of wastewater per year; previously, all that dirt ended up in the Neva and the Gulf of Finland.

The environmental effect achieved due to the construction of the the Northern Tunnel Collector is comparable with that of the South-West Wastewater Treatment Plant (the SWTP design capacity is 330,000 m3/day).

98.4 % of all wastewater has been treated in Petersburg since 10 October 2013.

 Whereas, before 1978, the former Leningrad had almost no wastewater treatment.

It is not an overstatement to say that many of the works performed during the Collector construction were unique. One example is the construction of Novoorlovskiy tunnel, an inverted siphon under the Neva, delivering wastewater from the left bank to the Collector. Another example is the tunneling in the wash-out zone. The German-made special tunneling machine was used to pass the distance from Arsenalnaya st. to the Lenin Square. A very challenging task was to build the Pumping Station in a 90m deep, 24m diameter shaft constructed for this purpose.

The Northern Tunnel Collector Extension Project was financed from several sources: federal budget, St. Petersburg budget, Vodokanal’s own funds, and the money provided by international financial institutions (the Nordic Investment Bank, the European Bank for Reconstruction and Development, the European Investment Bank, Northern Dimension Environmental Partnership (NDEP), Ministry of the Environment of Finland, Swedish International Development Cooperation Agency (Sida).

The total cost of construction works under this project is about 28.3 billion Roubles (at values of different years).

The completion of the Northern Tunnel Collector Project will lead to a significant improvement of both environmental situation and the quality of life in St. Petersburg, it will give an impetus to development of new city districts and the neighboring areas of the Leningrad Region.

In the coming years, Vodokanal will close the remaining direct discharges, first of all, on the Admiralteyskaya Embankment, at the Okhta and Karpovka Rivers. As a result, the wastewater treatment level in Petersburg will be near 100 %.

However, quality is no less important than quantity when it comes to wastewater treatment.

Currently, Petersburg is one of the few Baltic cities that fully meet the recommendations of the Baltic Marine Environment Protection Commission (HELCOM). Enhanced nutrient removal technologies are implemented at all municipal treatment plants to remove nitrogen and phosphorus which initiate the growth of blue-green algae. Concentrations of phosphorus in the total volume of wastewater discharge do not exceed 0.5 mg/l, nitrogen – 10 mg/l. Phosphorus and nitrogen are the HELCOM’s major focus of interest because these substances intensify the growth of blue-green algae (blue-green algae are the main threat to the health of the Baltic Sea).