KSB aids Polish wastewater upgrade

6 min read

When the wastewater and effluent infrastructure of the historic city of Krakow in Poland was in urgent need of renewal and updating, the main objectives being to improve the treatment of sewage which eventually flows into the Baltic Sea. A number of KSB's sewage submersible pumps and mixers were used to fulfil this objective.

For many countries that have in recent years become members of the European Union, investing in their environmental infrastructure has become a major priority. The provision of potable water and the treatment of wastewater and effluent are two of the highest profile examples, particularly in those countries where there has been a lack of investment over many years. The upside to this is that where new treatment plants and supply networks are being constructed, the organisations responsible are taking advantage of the best technologies available.  

High priority investment

Poland is one example of a country where investment in both the water supply and the treatment of wastewater and effluent has been afforded a much higher priority in recent years. The historic city of Krakow provides an excellent example of the progress that can be made by the determination of its municipal water company (MPWIK) and the financial resources available through ISPA (Instrument for Structural Policies Pre-Accession) and EU grants.

The first stages of developing an integrated wastewater and effluent treatment infrastructure for Krakow Plaszow started at the end of the 1950s. At first it was planned to build both mechanical and biological treatment plants, but financial constraints meant that only mechanical treatment plants could be built. By 1977 the plant had reached its planned capacity of 132,000 m3/s per day. In 1994 further investment was made to increase the effectiveness of handling chemical sediment.

Over the past 12 years, almost €86 million has been invested in the two major treatment plants built to service Krakow, the first project being the Kujawy works in the centre of the city. This was re-constructed in 1999 and now complies with Polish and EU environmental legislation. The latest investment programme, Plaszow II has involved increasing the volume of wastewater and sewage being treated from 132,000 m3/s per day to the 656,000 m3/s per day necessary in the rainy season. The investment has also included building additional water pumping stations and many kilometres of pipelines to transport water and effluent. Significantly, these projects have drawn on the technical resources and water industry experience of KSB.

The main objectives of the investment in the wastewater and effluent treatment plant upgrades were to improve the treatment of sewage in the Krakow region and the water quality of the Vistula River, which eventually flows into the Baltic Sea. To realise these objectives MPWIK embarked on building new, and extending existing facilities, together with purchasing the necessary infrastructure. At the time of embarking on the Plaszow II modernisation development programme, the plant was handling 20% more effluent than its original design capacity resulting in harmful discharges that did not meet Polish and EU standards passing into the nearby river Drwiny.

The modernisation at the Plaszow II plant has included the construction of a biological sewage treatment plant with a capacity of 328,000 m3/s per day, comprising five biological reactors, five secondary sediment stations and a blowing station. In addition there has been the creation of a tertiary treatment plant, including sludge handling and bio-gas utilisation. This investment has realised the aim of removing all sewage from the centre of Krakow and treating it using both mechanical and biological processes, thereby servicing almost half a million residents and also ensuring compliance to Polish and EU legislation and restoring the cleanliness of the local rivers. Using money remaining from the development of the Plaszow II plant, MPWIK has built a plant for burning the dried sludge for cogeneration.

Best possible technologies

MPWIK is owned and operated by the municipal authority, so it is answerable both to the Mayor and the citizens of Krakow. It is, therefore, important that it sources the best possible technologies and support services both for the international grants and the income received from customers. Zenon Kaleta of MPWIK explains: “An essential factor when we were sourcing pump suppliers was for units with a high pumping capacity, operating reliability, quality, availability and references on similar sized projects. The chosen supplier had to be able to demonstrate previous experience in the planning, design and implementation of extensive projects across all areas of modern treatment technology. Equipment also had to demonstrate energy efficiency, long service life and reliability.”

Using these selection criteria, MPWIK found that KSB Poland, with its extensive product base of pumps and mixers, together with its long association with the wastewater and water supply industries, fulfilled its many demanding requirements. KSB Poland has been an ever-present supplier throughout both the Kujawy and Paszow II development programmes, providing several ranges of pumps, mixers and technical engineering services. However, its activities have not been confined to just these two projects; pumps and mixers have also been installed at 62 remedial plants in and around the city. KSB has also refurbished existing facilities and supplied new pumps for 14 new water pumping stations located near the former Lenin Steelworks, on land which is currently undergoing regeneration and reconstruction.

When first invited to tender for the Kujawy and Plaszow refurbishment and regeneration programmes, KSB found it necessary to make a thorough study of the existing infrastructures and the influences on the nature of the wastewater and effluent being treated. One of the age-old problems for the existing pumping station and treatment works infrastructures was coping with the large volumes of grit and chemicals present during the winter months. Because of the long winters and high snow content, grit and chemicals are used to keep the roads clear, and these materials eventually enter the wastewater treatment process causing both blockages and corrosion. In the refurbishment of existing, and the design of new, pumping stations and treatment works, KSB was able to recommend at the design stages alternative pump types that would address these problems and provide long trouble-free operating life.

“We had to collect as much information about the area and the factors influencing the nature of waste being handled,” says Wojciech Pasterz of KSB Poland. “Depending on the kind of waste, we can address the issue of hydraulics and special pump materials. The strength of KSB is that we have a wide range of pumps, impellers, hydraulic elements and materials which are proven elsewhere in the effluent treatment and water supply industry. We started by listening to the client’s requirements; typically where the problems existed and what were the most common problems.”

Wojciech Pasterz continues: “The scope of our involvement in the projects has encompassed supplying all of our fluid handling technologies designed for the wastewater, effluent and water supply industries. The range of products that we have supplied includes Amarex, Amacom, Sewabloc, Omega and Etanorm pumps, and Amamix and Amaprop submersible mixers. However, our involvement has gone far beyond the requirements of supplying equipment. Over 10 years ago, we set up a dedicated maintenance plant for our customer, including full training facilities for their staff.”

The largest sewage treatment pumps supplied are 130 kW submersible pumps capable of 1100 litre/s and a head of 10 m. For water transfer Omega and Etanorm pumps up to 250 Kw give a maximum flow of 1200 m3/hr, but operate at higher pressures in order to provide a head of up to 70 m. Mixers are used for denitrification of the sludge in the tanks to keep the sludge active and not let it settle. The 60 mixers supplied for the Plaszow II plant mean that it now has the capability to handle in excess of 165,000 m3/s of sludge each day.

Standardisation

In order to get the best possible return on their investment, MPWIK elected to use only a small number of equipment suppliers for all its regeneration and new build projects. Working with a small group of suppliers allowed it to standardise on proven pumps and mixers for specific applications and get the best value for money. Also they would benefit over the long term by ready access to spares and components, together with having maintenance engineers being familiar with the manufacturers’ technologies. The ability to provide MPWIK with full training facilities was a significant factor in KSB gaining preferred supplier status. Having inherited an ageing and inadequate infrastructure and a workforce of around 150 employees with varying skills and resources, the KSB training courses enabled MPIK to retain these employees and improve their skills.

Krakow has big and ambitious plans to develop all the areas of the city and its environs. Whereas at one time the sole objective was to supply the population with clean water, the treatment of effluent was not given the attention it deserved so the treatment infrastructure was neglected. This presented problems when it came to collecting and harvesting water as the local river was not considered to be a safe source of potable water due to effluent discharges. The reduction of Krakow’s industrial manufacturing base in recent years and drop in population as residents have moved out to surrounding towns and villages has reduced the pressure on the water supply resources and levels of pollution. However, as it has become far more of a tourist destination, there has not been any reason for complacency.

One of the advantages of moving from a water supply and effluent treatment infrastructure that has either been non-existent or antiquated is that it is possible to approach the challenges with a completely new set of objectives that allow the most modern technologies to be used. MPWIK set out with a quality management programme developed in line with the best European standards. As a result, Krakow has the most modern water supply and treatment infrastructure in Poland. It is the only city to treat 100% of its effluent and in order to fund further investment it is now offering its supply and treatment facilities to other towns and villages that do not have waste treatment facilities and this is a valuable stream of revenue.

Matching pumps and mixers

For KSB, the projects of the last few years and the continuing investment have provided a platform for the company to demonstrate the effectiveness of its pumps and mixers. By matching pumps and mixers to the specific requirements of the various applications, KSB has realised energy savings costs for its customer and established a highly qualified service and maintenance division that reduces the costs associated with plant and equipment downtime.

Today, Krakow is the only city in Poland to have a fully-regulated and integrated water and sewage treatment infrastructure and other municipalities can learn from its experience.