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The purpose of this study was to investigate the feasibility of ethanol as an alternate substrate for biological denitrification by measuring various growth kinetic parameters. The growth yield coefficient is measured for endogenous nitrate removal while external carbon substrate is still available for denitrifying population. In this study, 3 SBR...
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In this study, the Denitrifying Sulfur cycle-associated Enhanced Biological Phosphorous Removal (DS-EBPR) with 20 mg P/L/d of the volumetric P removal rate was successfully achieved in a Sequencing Batch Reactor (SBR). The effects of carbon-to-sulfur (C/S) mass ratio and nitrate (N) dosage were investigated through two batch tests to reveal the rol...
The effect of pH on nitrous oxide (N2O) production rates was quantified in an intermittently-fed lab-scale sequencing batch reactor performing high-rate nitritation. N2O and other nitrogen (N) species (e.g. ammonium (NH4+), nitrite, hydroxylamine and nitric oxide) were monitored to identify in-cycle dynamics and determine N conversion rates at cont...
Citations
... Methanol has some other advantages, such as lower sludge production which increases the efficiency of denitrification, and lower methanol to nitrate ratio [13]. However it is less efficient at removing nitrogen in winter (7.5 mgNO 3 -N/L) rather than summer temperature (3 to 5 mgNO 3 -N/L) at Blue Plains AWTP [14]. In addition, due to methanol toxicity and flammability, the operation and maintenance cost for handling, transportation and storage must be considered with safety concerns. ...
Influence of external carbon dosage for balancing denitrification kinetics for heterotrophic organisms is necessary to understand the efficiency of biological nitrogen removal from wastewater. The aim of this study was to evaluate the long term effect of ethanol dosage on heterotrophs. Three experiments were performed for 38 hours with a single dose at 1.2 mgCOD/mgTSS of food to microorganism ratio. We observed that organisms needed at least 20 hours to acclimate to ethanol based on specific denitrification rate (SDNR) and carbon to nitrate (C/N) ratio. However, for multiple dosage of ethanol for 67 hours of contact time showed that SDNR increased by more than five times compared to single dosage. In this case, the C/N ratio and anoxic yield coefficient decreased as N2O emission increased during multiple times of ethanol addition. The maximum of 4.4% of N2O emission was observed at C/N ratio of 4.38 mgCOD/mgNO3-N. It was concluded that higher influent C/N ratio for longer time contact with biomass was responsible for producing N2O gases which inhibited the yield. Thus, the possibility of using optimal ethanol dose with specific feeding time is critical to estimate the correct carbon requirement for denitrification.
This study investigated five different trace organic contaminants (TOrCs) (one hormone: 17α-ethinylestradiol (EE2), two pharmaceuticals: salicylic acid (SA) and trimethoprim (TMP), one analgesic drug: carbamazepine (CBZ), and one surfactant metabolite: nonylphenol (NP)) removal efficiency at a full-scale Advanced Wastewater Treatment Plant (AWTP). The AWTP achieved average EE2, SA and NP removal over 80% at the biological carbon removal stages. The results also showed a 66% removal of TMP at the nitrogen removal stages. CBZ was recalcitrant throughout the plant, due to its high solubility and low distribution coefficient between wastewater and sludge. Batch experiments were conducted on active and inactive secondary, nitrification and denitrification sludge by adding TOrCs to understand the removal mechanism through sorption and biodegradation. Sorption was the dominant mechanism to remove EE2, SA and NP in secondary treatment processes. In nitrification and denitrification processes, higher percentage of TOrCs removal through biodegradation were observed compared to removal through sorption.
