TECHNOLOGY

Water supply

The first water supply system built in the city was based on the construction of the Radunia Channel in the mid-14th century. Drinking water was transported through wooden or brick pipes from the channel to 600 public wells. Some pipes still exist in the ground of the Old Town.

A modern water supply system was designed by E. Wiebe in 1865, and in 1869 a groundwater intake Pregowo was constructed 20 km away from the city and 110 metres above sea level. About 10 400 m³ of water was delivered per day by gravity via cast-iron pipes (diameter 418 mm). This water supply system is still in use, providing daily 6500 m³ water for consumers.

The consumption of water increased steadily as the city grew and new suburbs were built. A new water intake station was built in 1878 in Polanki. At the Polanki plant water was aerated and filtered. Polanki served as a water supplier until 1996, and today it is a reserve supplier.

In the 1930s the total annual water production reached 9 million m³. Before the Second World War altogether eight water intake plants provided water to the city, and six of them had water treatment facilities.

After the Scond World War the water consumption has increased steadily, thus the capacity of the existing water plants has been enlarged and new plants were built in order to satisfy the needs. In 1986 the first surface water intake plant was constructed. Thereafter the exploitation of groundwater resources could be limited in order to improve the quality of water.

Today 17 water intake plants provide water in Gdansk, 75 % of the water comes from the groundwater resources and 25 % from surface water plants.

Sewerage system

Early waste disposal was in the form of latrines which emptied into the rivers through open ditches. This system served for 500 years. Later the ditches were covered with planks and used as pavements.

In 1865 the design of a new sewerage system was published. In 1872 this sewerage system, with a pumping station and a biological wastewater treatment plant in Gdansk, became operational. The Stogi plant consisted of settling tanks, filtration and irrigation fields. In the beginning all municipal wastewater was treated in this plant.

But as there was no possibility to enlarge the filtration fields of this plant, new treatment plants were built to purify the growing amounts of sewage. In the beginning of the 20th century three local treatment plants were built in Sopot (filtration fields), Oliwa (biofilter) and in Zaspa, a mechanical treatment plant with primary settling tanks that was designed by the famous German engineer K. Imhoff. In 1930 the Zaspa plant was enlarged and modernised and the two other local plants were closed. In 1932 the Zaspa plant was the largest activated sludge plant on the Continent with a flow rate of 12 000 m³ per day. After the war the enlargement of the Zaspa plant continued.

Because of the increase of the wastewater volume it was necessary to build a new wastewater treatment plant, Wschód, which was completed in 1976. The Stogi plant was closed in 1991 and Zaspa will operate until 2005. In 1988 the Swarzewo wastewater treatment plant was built for the towns and villages near Puck Bay (the western part of Gdansk Bay). After this investment the quality of water in Puck Bay started to improve.

1997 - 1999 was the saw the Wschód plant modernised with chemical treatement facilities, treating 100,000 m³ of sewage per day. The inflowing sewage contains 90% of the municipal and 10% of the industrial sewage. The biological facilities are under construction.

Articles

M. Swinarski
The development of waste water treatment systems in Gdansk in 1871-1998
(European Water Management, Volume 2, Number 4, August 1999: 69-76)
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Piotr Kowalik
The significance of engineering and technology in the history
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