RYKI, Poland – The first Nereda installation in Poland in the city of Ryki has celebrated a year in operation and has met all effluent requirements.
This is the first installation located in the eastern part of Central Europe dealing with very low process temperatures in the order of 7–8 °C during the winter period.
The Ryki Nereda plant is designed to treat 5,320 m3/day (dry weather), corresponding to 38,600 PE (population equivalent).
Beyond the temperature challenge, the plant combines the treatment of different incoming sewages (domestic, septic tanks and industrial) and has to handle extended industrial peak load periods.
Nereda is Royal HaskoningDHV’s patented full-scale municipal and industrial wastewater treatment technology that utilises aerobic granular sludge, developed through a collaborative public-private partnership involving Dutch wastewater treatment stakeholders, the Delft University of Technology (the Netherlands), various treatment plant end-users and Royal HaskoningDHV.
It was in 2012 DHV Hydroprojekt, a Polish company of Royal HaskoningDHV group won the public tender for the complete design of the new Ryki Wastewater Treatment Plant (WWTP) for Przedsiebiorstwo Gospodarki Komunalnej i Mieszkaniowej (PGKiM), located in eastern Poland in the Province of Lublin.
The Nereda solution was said to have successfully responded to important criteria in the tender evaluation process such as low capital expenditure and low total operating costs.
The construction of the plant was awarded by SKANSKA (contractor) and DVH Hydroprojekt was appointed as the subcontractor responsible for the Nereda detailed design, supply of equipment to the reactors and the start-up of the installation.
The start-up of the plant was initiated in February 2015 and the Nereda reactors were both inoculated with conventional activated sludge, mainly transferred from the old works and a small portion from an external conventional WWTP.
At the time of the start-up the biomass concentration in the Nereda reactors was only 2 g/ℓ and therefore it was necessary to gradually increase the treatment capacity available in the new installation.
Two months after the start-up was initiated the new Nereda installation was able to treat the total incoming sewage reaching the plant and the old SBR reactors were decommissioned.
Since start-up the Ryki WWTP has been challenged by very low wastewater temperatures as compared with the intended minimum design temperature (12 °C).
The biological process in the Nereda reactors was initiated in almost freezing conditions (approximately 4 °C) and only three months later (end of April) the design temperature was achieved.
The highest process temperature (23 °C) was reached in August 2015 (in summer), and since then a strong negative trend has been noted and less than 8 °C in the reactors was measured during most of January 2016.
Since April 2015 (two months after the initiation of the plant start-up) Ryki WWTP has been showing “an excellent performance constantly meeting the effluent standard requirements”, according to Royal HaskoningDHV.
The plant operation is said to be positively responding to the peak industrial load (registered between September and December), as well as to extremely low wastewater temperatures (< 8 °C on average) noted in January and February 2016.
To date more than fifteen full-scale municipal and industrial Nereda plants are in operation and another fifteen are under construction (with a total installed capacity of about 5 million PE).
In Poland, the Netherlands, South Africa, Portugal, Ireland, United Kingdom, Switzerland, Sweden, Australia and Brazil there are already Nereda plants in operation or under construction.
Andrzej Waszczuk, director for municipal services in PGKiM, said: “Thanks to Nereda, treated sewages meet EU standards and we achieve established ecological effect. It should be emphasised, that it would not be possible without a very good cooperation with DHV Hydroprojekt.”