The 4.79-Billion Rebuild Nobody Is Meant to Notice

Prague starts rebuilding the old water line of its central wastewater treatment plant on Císařský ostrov on 1 October. The tendered price is 4.79 billion crowns before VAT, the works are timed at 43 months, and the plant will keep treating the city's sewage throughout — on the other line. Officials of the city and of Pražská vodohospodářská společnost (PVS), which runs the modernisation, put the figures to journalists on 16 September. ČT24 reports that the start follows eight years of preparation.

We start on 1 October, when the site will be handed over. The construction is for 43 months and the tendered price is 4.79 billion crowns before VAT. What needs to be mentioned, though, is that the construction will be carried out under the so-called FIDIC commercial conditions, which is a measured contract. So the price bid represents unit prices for individual operations and materials, but invoicing will always follow the actual measured volumes.

— Pavel Válek, director of PVS

The work goes to a consortium led by SMP Construction, of the Vinci group, which also built the newer line. That earlier line cost 7.3 billion crowns and was commissioned in 2019, and it is the reason this reconstruction is possible at all: an eight-month shutdown of the old line, transferring its work to the new one, is being completed now.

A Praguer should not notice anything.

— Pavel Válek, director of PVS

Válek added that while the newer plant can do the work of both for a short period, it cannot do so long term, which is why reliable and clean operation needs both lines.

What a water line is

Petr Mrkos, director of Pražské vodovody a kanalizace, described the object of the contract to ČT24 in plainer terms than the price tag suggests.

The water line is essentially a biological reactor in which the main pollutants, nutrients, mainly nitrogen and phosphorus, are removed.

— Petr Mrkos, director of Pražské vodovody a kanalizace

On his figures the plant handles roughly 3.5 cubic metres a second in fine weather, and up to eleven cubic metres a second when it rains. Each of the two lines is designed for 800,000 population equivalent — the unit expressing the pollution load of one average person. Once the old line is modernised, Válek said, the plant as a whole should be able to treat the wastewater of up to two million people, which is meant to cover the population growth the city expects over coming decades.

Petr Kubala, director of Povodí Vltavy, made the case from the river's side.

Under the current unfavourable hydrological situation, which can and will repeat itself, it is very important that what is discharged into surface waters meets the requirements.

— Petr Kubala, director of Povodí Vltavy

He argued that this gives the investment a significance beyond the region, because it affects the whole course of the Vltava below the city and the Elbe as well. The 2019 line, on his account, has met every expectation: all parameters were always met during trial operation.

Who pays, and over how long

The city pre-finances the investment and PVS repays it over the next thirteen years out of the sewerage charge collected from customers. That mechanism was set in 2022, when the city approved financing the plant from water and sewerage charges; since then the charge has risen annually by two percentage points above inflation, and is due to keep doing so until 2028, after which the increase is to track inflation only.

This contract is one piece of a modernisation of the whole plant estimated at 36 billion crowns. Next in line after it are the sludge management and the technology for a further stage of treatment, which the European Union requires to be in place by 2033.

It is worth saying plainly what the shape of this is. Prague is spending nearly five billion crowns, over most of four years, on a facility almost no resident will ever see, to produce an outcome defined as nothing changing. The visible city argues about towers and tram tracks; this is the other half of the built environment, and the bill for it lands on the sewerage charge either way.