Description

WWTP Sjölunda is located in the city of Malmö in the south part of Sweden and only 20 minutes away from the international airport of Kastrup in Copenhagen. At Sjölunda, enhanced carbon extraction is also of high interest for two reasons: to increase the biogas production and to reduce the air demand in the high-loaded activated sludge where any remaining organic matter after pre-treatment is today oxidized.


In addition, project partners will demonstrate how to further remove nitrogen from the mainstream using the concept of partial nitritation and anammox. 

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Objectives

  • Achieve high carbon extraction capacity through pre-filtration with microscreen with minimum chemicals and lowest possible remaining COD for further treatment in nitritation+anammox process
    • Measured by conventional chemical test kits and mass-balances
  • Large-scale prototype demonstration based on a 3-stage concept with 2 different pre-treatment processes for BOD removal: Phase 1: primary clarifier and high-load AS; Phase 2: disc filter + high-load followed by nitritation and anammox (MBBRs) for stable nitrogen removal in main stream water
    • Measured by conventional chemical test kits and mass-balances
  • Demonstration control scheme – stable and safe (remote control and online monitoring)
  • Optimisation of nitrogen removal capacity in main stream nitritation+anammmox process
  • Microbial characterization in biofilm of main stream nitritation+anammmox process
    • Batch trial on carriers for measurements of activity
    • Characterization of biofilm structure
    • Microbial characterization
  • Demonstration of energy balance
    • Measured by energy consumption and compared to the previous treatment
  • Transfer to operation personnel (reduced operation costs, savings in aeration & Substrate)
    • Measured by cost calculations
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Challenges

Nowadays, carbon extraction is achieved at a rate of 30% in the primary settler. The enhanced extraction of carbon POWERSTEP is aiming for is very important to reach the objective of “energy-positive” wastewater treatment plant. The carbon source is important to gain biogas out of the wastewater and the more carbon you get the higher the biogas yield at the end of the day. Therefore, an enhanced biogas production means less energy needs for water treatment. But an increased carbon extraction typical challenges nitrogen removal, given the dependence of denitrifying bacteria on an easily accessible source of carbon.
 

However, at Sjölunda WWTP carbon is removed in a high-loaded activated sludge and nitrogen is primarily removed in a two-step process with a nitrifying trickling filter and post-denitrifying Moving Bed Biofilm Reactor (MBBR) using methanol as external carbon source. 
In the POWERSTEP project, nitrogen will be removed using a two-stage MBBR with nitritation + anammox. The concept is innovative because it’s ability to give high extraction of carbon for biogas production, nitrogen removal with low energy requirement and compact footprint and to omit or at least dramatically decrease the requirement for external carbon source.

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Download the case study flyer!

POWERSTEP Case Study flyer

Download the scientific poster:

CS2 Scientific poster

 

Local Associated Partners

At Sjölunda, POWERSTEP project partners rely on the support of:

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