Adam Drzewicki

Limitation of Sludge Biotic Index application for control of a wastewater treatment plant working with shock organic and ammonium loadings

This study aimed to determine the relationship between activated sludge microfauna, the sludge biotic index (SBI) and the effluent quality of a full-scale municipal wastewater treatment plant (WWTP) working with shock organic and ammonium loadings caused by periodic wastewater delivery from septic tanks. Irrespective of high/low effluent quality in terms of COD, BOD5, ammonium and suspended solids, high SBI values (8-10), which correspond to the first quality class of sludge, were observed. High SBI values were connected with abundant taxonomic composition and the domination of crawling ciliates with shelled amoebae and attached ciliates. High SBI values, even at a low effluent quality, limit the usefulness of the index for monitoring the status of an activated sludge system and the effluent quality in municipal WWTP-treated wastewater from septic tanks. It was shown that a more sensitive indicator of effluent quality was a change in the abundance of attached ciliates with a narrow peristome (Vorticella infusionum and Opercularia coarctata), small flagellates and crawling ciliates (Acineria uncinata) feeding on flagellates.

Microfauna community during pulp and paper wastewater treatment in a UNOX system

This study characterized the microfauna community during treatment of pulp and paper wastewater in a UNOX system aerated with pure oxygen, and with a high organic loading rate (0.4±0.06kg BOD/kg MLSSday), low sludge retention time (3.73±0.33 day), and high oxygen concentration (≤20mg O2/L) in comparison to municipal treatment systems. In the aeration tank, temperatures were high, averaging 35.7°C (March-May), then 38.9°C (June-August). Effluent quality was acceptable: 180±22mg COD/L, 7.2±2.1mg BOD5/L, and 33±5mg TSS/L. At 35.7°C, 5 taxa were identified in the activated sludge: small flagellates (flagellates <20μm), attached ciliates (Vorticella infusionum, Vorticella octava), crawling ciliates (Chilodonella uncinata) and free-swimming ciliates (Sathrophilus muscorum). During this period, the SBI (Sludge Biotic Index) was 6-7, corresponding to Quality Class II. At 38.9°C, two taxa co-dominated (Vorticella infusionum, Sathrophilus muscorum). When Vorticella infusionum dominated, the SBI was 5 or 7 (Quality Class III/II); when Sathrophilus muscorum dominated, the SBI was 0 (Quality Class IV). Slight changes in the abundance of two opposing Madoni keygroups impeded proper classification of activated sludge. However, effluent quality remained the same, showing that these indicators of activated sludge quality do not always reflect effluent quality.

Effect of a static magnetic field on activated sludge community

ABSTRACT The aim of this study was to determine the effect of a static magnetic field (SMF) on the composition of activated sludge biocenosis. The experiment was carried out in two parallel bench scale Sequencing Batch Reactors (SBRs). Both SBRs were treated with dairy wastewater. The activated sludge in the first SBR was exposed to an SMF via the induction of a 0.6 T magnetic field generated by four magnetic liquid activators. The second reactor (control reactor) was operated at the same operational parameters but the activated sludge was not exposed to the SMF. The mean length of the bacterium Eikelboom Type 0092 was lower in the SMF-exposed reactor than in the control reactor. Different activated sludge morphologies in SBRs were reflected in the values of the sludge volume index and sludge biotic index calculated on the basis of the microfauna composition.

Impact of Flowback Water on Activated Sludge Biocenosis During Municipal Wastewater Treatment

Abstract The aim of this study was to determine the effect of flowback water on an activated sludge biocenosis during municipal wastewater treatment in the sequencing batch reactors (SBRs). Two series were performed. In series 1, only municipal wastewater was treated, whereas in series 2, municipal wastewater with pre-treated flowback water was used. Flowback water constituted 3-5% of the influent and was introduced to the SBRs twice per week. Introducing flowback water did not decrease the quality of effluent from the SBRs. However, the composition of the activated sludge biocenosis differed between series, ie the biodiversity of protozoa and the relative abundance of microfauna in functional groups changed after flowback water addition. Polymerase chain reaction - denaturing gradient gel electrophoresis (PCR-DGGE) showed that the ammonia oxidizers community responded faster to flowback water addition than the total bacterial community and remained relatively stable during treatment. However, after 9 weeks of exposure to flowback water, ammonia oxidizing bacteria (AOB) biodiversity decreased. This suggests that prolonged exposure could cause nitrification problems, leading to deterioration in effluent quality