Nereda design capacity

  • 5601 m3/d
    Dry Weather Flow
  • 465 m3/h
    Peak Flow
  • 41000 PE
    PE (PE = 60 gBOD/d)

Project facts

  • Client
    Przedsiebiorstwo Gospodarki Komunalnej i Mieszkaniowej
  • Licensee
    Aquatex Maxcon
  • Location
    Ryki, Poland
  • Period
  • Wastewater
  • Project type
  • Process configuration
    Pre-treatment + Nereda + Effluent pond

About the Ryki, Poland Nereda WWTP

Ryki WWTP is located in the Polish city of Ryki, in the eastern Polish province of Lublin.

The challenge

In addition to the usual considerations – such as increasing capacity due to population growth and new regulatory requirements – the WWTP in Ryki needed to be able to deal with very low process temperatures of 7 to 8 °C during the winter months. The plant also combined the treatment of different incoming sewages, such as domestic, septic tanks and industrial, and was required to handle extended industrial peak load periods.

Poland Ryki | Royal HaskoningDHV

Image: Overview of the Ryki WWTP

The solution

In 2012 DHV Hydroprojekt, a Polish division of Royal HaskoningDHV group, won the contract for the complete design of the new Ryki WWTP for Przedsiebiorstwo Gospodarki Komunalnej i Mieszkaniowej (PGKiM). The use of Nereda technology was the first time it had been implemented in Poland. Key to Nereda being selected was that it fulfilled certain important criteria, including low capital expenditure and low total operating costs. It also needed to be able to operate successfully in a variety of different temperature conditions. Skanska was the main contractor, with DHV Hydroprojekt as subcontractor responsible for the Nereda components, including design, supply and start-up of the installation. The Ryki Nereda plant is designed to treat 5,601 m³/day in dry weather, with peak flow of 465 m³/hour, serving a 41,000-population equivalent. The start-up of the plant was initiated in February 2015 and over a two-month period the treatment capacity was increased until the new installation was able to treat the total incoming sewage and the old reactors were decommissioned.

The outcome

The works performed as designed for and successfully dealt with considerably lower wastewater temperatures than initially planned. The anticipated minimum design temperature was 12°C, but when the Nereda reactors were started-up water temperature was as low as approximately 4°C and only three months later, at the end of April, the design temperature was achieved.


  • Extremes of temperature conditions

  • Low noise and odour

  • Low capital expenditure

  • Reduced operating costs

  • Superb performance in challenging location