SHORT TERM CHEMICAL TREATMENT OF BIOLOGICAL SLUDGE WITH FILAMENTOUS ORGANISM TYPE 021N
When sludge bulking occurred in the new wastewater treatment plant for the abattoir in Kalmar, a quick solution to inhibit and harm the filamentous organism Type 021N was to be found. Five different kinds of chemicals (NaOCl, H2O2, FeCl3, PAX-XL60 and Ecofloc) were tested in two short term lab-tests. Each chemical was first tested with five different dosing rates and an exposing time of one hour then with one dosing rate and an exposing time of 14 hours. Both test series were carried out with pH-adjustment if necessary and with continuous aeration. The samples were analyzed with a phase-microscope and pictures of all samples were taken with 100, 200 and 400 times enlargement.
The evaluation gave no satisfying results because the filamentous bacteria were either not harmed at all or they were harmed while at the same time most of the indicating organisms were severely damaged. The chemical PAX-XL60 gave, however, negative effect on the filamentous organisms, positive flocculation and did not harm the indicating micro organisms as severe as the other chemicals.