Phase 1 condition 2

Removal Efficiency (%) 2nd Condition Ozone

Average Removal end of condition 2

  • 3 samplings in october 2019
  • 30 compounds analysed
  • 20/30 removal efficiency calculable
  • Rest never above detection level or not fullfilling the removal rate calculation demands

Average removal
65% by biology
79% after first point ozonation
86% after multiple point ozonation

Removal efficiency after ozonation condition 1 (june ‘19).  In the reference line some micropollutants are removed better than others and this corresponds with the findings from the autum ’18 and gives an average removal of 63%. In the experimental line with 2 times ozone injection a whole other picture is seen. After just one point of ozonation an average removal of 78% was observed and after injecting ozone a second time (tertiary) it reached 93% removal in average!

Micropollutant concentration vs. PNEC

Above PNEC end of condition 1

  • 3 samplings in october 2019
  • 36 compounds investigated
  • 5 > PNEC in inlet wastewater

3 > PNEC after conventional biology
0 > PNEC after multiple point ozonation

After the first condition of ozone its clear to see the improvement. In the reference line 5/36 compounds were above PNEC in the outlet. However, after multiple point ozonaton none of these 5 micropollutants is even detectable in the waterphase anymore. In fact, 32/26 came below limit of detection (LOQ).

Only 3 are above in the reference line, but not far above PNECs -> could be due to a lot of water to the plant in October 2019 (approx. 200.000 m3) comparred to october 2018 (60.000m3)

Sludge Volume Improvement 

Mixed-liquor ozonation can effectively reduce sludge volume