Impact of Biological Nutrient Removal Process OperatingandDesignConditions on theRemoval ofMicropollutantsfromWastewater
Olumuyiwa Omotola Ogunlaja
presented to the University of Waterlooin fulfillment of thethesis requirement for the degree ofDoctor of Philosophyin
A thesis
Civil Engineering
Waterloo Ontario Canada 2015
AUTHOR'SDECLARATION
I hereby declare that I am the sole author of this thesis. This is a true copy of the thesis including any required final revisions as accepted by my examiners.I understand that my thesis may be made electronically available to the public.
Abstract
The efficacy of three different wastewater treatment configurations conventionalactivated sludge (CAS) nitrifying activated sludge (NAS) and biological nutrientremoval (BNR) for removal of selected micropollutants from authentic wastewater wasinvestigated. The processes were also characterized based on their proficiency to reducethe estrogenic activity of the influent wastewater using the in-vitro rebinant yeastassay. The selected micropollutants (MPs) covered a broad spectrum of therapeutic(meprobamate (MEP) and carbamazepine (CBZ) lipid lowering drug (Gemfibrozil(GEM)) antibiotic (trimethoprim (TMP) and sulfamethoxazole (SMX) steroid hormone(androstenedione (ADR)) estrogen (estrone (E1) and estrogenic pounds (nonylphenol (NP) and bisphenol A (BPA). The removal efficiency of TMP improved with theplexity of the three treatment process configurations. IBU ADR SMX NP E1 andBPA had moderate to high removals (> 65%) while CBZ and MEP remained recalcitrantin the three treatment process configurations. The removal of GEM was better in theNAS than in BNR and CAS treatment configurations. The YES assay analyses showedan improvement in estrogenicity removal in the BNR and NAS treatmentconfigurations as pared to the CAS treatment configuration. Comparing theestrogenic responses from the three treatment configurations the removal efficienciesfollowed the order of BNR = NAS > CAS and all were greater than 81%.Ⅲi
The removal of estrogenicity in a University of Cape Town- biological nutrientremoval (UCT-BNR) wastewater treatment processes was investigated using pilot andbench scale systems batch experiments and mathematical modeling. In the pilot BNRprocess 96 ± 5% of the estrogenicity exerted by the EDCs in the wastewater wasremoved by the treatment process. The degradation efficiencies in the anaerobic anoxicand aerobic zones of the pilot BNR bioreactor were 11± 9% 18 ± 2% and 93 ± 10%respectively. In order to further understand the performance of the BNR process in theremoval of EDCs from wastewater a bench scale BNR process was operated withsynthetic wastewater dosed with E1 and E2. The removal of estrogenicity in the benchscale system (95 ± 5%) was parable to the pilot BNR process and the degradationefficiencies were estimated to be 8± 0.8% 38 ± 4% and 85 ± 22% in the anaerobic anoxicand aerobic zones. A biotransformation model developed to predict the fate of E1 andE2 in batch tests using the sludge from the BNR process was calibrated using the datafrom the experiments. The biotransformation rate constants for the transformation of E2to E1 were estimated as 71 ± 1.5 31 ± 3.3 and 1 ± 0.9 L.gCOD-d1 for the aerobic anoxicconstants for the transformation of E1 were estimated to be 7.3 ± 1.0 3 ± 2.0 and 0.85 ±0.6 L-gCOD-d. A steady state mass balance model formulated to describe theinteractions between E2 and E1 in BNR activated sludge reasonably described the fateof E1 and E2 in the BNR process.
A bination of pilot scale biological nutrient removal (BNR) process batchbiotransformation of trimethoprim (TMP) in a BNR activated sludge. Theconcentrations of the active microbial groups- ammonia oxidizing bacteria (AOB) ordinary heterotrophic organism (OHO) and polyphosphate accumulating organism(PAO) in the BNR bioreactor were estimated to be 40 780 and 2710 g COD/m?respectively. TMP was biotransformed in all the redox zones of the BNR bioreactor. TheTMP biotransformation efficiencies in the anaerobic anoxic and aerobic sections were13 ± 12% 17 ± 10% and 24 ± 4% respectively. Batch tests with and without nitrificationinhibition showed that AOB played a role in the biotransformation of TMP in BNRactivated sludge. A pseudo first order model that incorporated the contributions ofPAO OHO and AOB to the overall biodegradation of TMP was found to describe thebiodegradation of TMP in batch tests with and without nitrification inhibition. Theestimated biotransformation rate constant with respect to PAO OHO and AOB were0.32 ± 0.06 0.58 ± 0.06 and 13.7 ± 0.06 L/gCOD/d respectively. This model showed thatPAOs OHOs and AOBs contributed towards the biotransformation of TMP in BNRactivated sludge with the trend AOBs = PAOs > OHOs.
