Tanner Ryan Devlin

Effect of extended famine conditions on aerobic granular sludge stability in the treatment of brewery wastewater

Results obtained from three aerobic granular sludge reactors treating brewery wastewater are presented. Reactors were operated for 60d days in each of the two periods under different cycle duration: (Period I) short 6h cycle, and (Period II) long 12h cycle. Organic loading rates (OLR) varying from 0.7kgCODm-3d-1 to 4.1kgCODm-3d-1 were tested. During Period I, granules successfully developed in all reactors, however, results revealed that the feast and famine periods were not balanced and the granular structure deteriorated and became irregular. During Period II at decreased 12h cycle time, granules were observed to develop again with superior structural stability compared to the short 6h cycle time, suggesting that a longer starvation phase enhanced production of proteinaceous EPS. Overall, the extended famine conditions encouraged granule stability, likely because long starvation period favours bacteria capable of storage of energy compounds.

Granulation of activated sludge under low hydrodynamic shear and different wastewater characteristics

Five reactors were operated with low upflow superficial air velocities (0.41cmmin-1) in order to observe granulation on synthetic wastewaters with different characteristics: 1) 340mg-CODL-1; 2) 630mg-CODL-1; and 3) 1300mg-CODL-1. Stable granulation was only observed under low hydrodynamic shear for low-strength wastewater. 55-70% of soluble chemical oxygen demand (COD) was utilized before aeration and 91% COD, 62% total nitrogen (TN), and 96% total phosphorus (TP) were removed from the low-strength wastewater. Although medium-strength wastewater did generate granules they rapidly acquired a filamentous surface layer that resulted in decreased performance and loss of nitrification. 94% COD, 30% TN, and 85% TP were removed from the medium-strength wastewater. The high-strength wastewater did not develop granules and 85% COD was removed. Results demonstrated that high shear force was not required for granulation. Rather, granulation depended on multiple parameters to out-select rapidly growing aerobic microorganisms.

Start-Up of an Anaerobic Moving Bed–Biofilm Reactor and Transition to Brewery Wastewater Treatment

AbstractTwo 4-L anaerobic moving bed–biofilm reactors (AMBBR) with different quantities of cubic media (25 and 35% by volume) were examined. Reactors were fed synthetic protein-based feed and both were shown to be capable of treating up to 20  kg/m3 day of chemical oxygen demand (COD), achieving 80% COD removal. Beyond that load the performance began to decrease. The maximum biogas production observed was 9.25  m3 CH4/m3  day at an organic loading rate (OLR) of 20  kg COD/m3 day. The methane composition varied between 60 and 70%. Averaged methane yields of 0.36±0.07  m3 CH4/kg COD removed and specific removal rates from 0.4 to 20  kg COD/m3 day were achieved. At the maximum OLR above 20  kg COD/m3 day, the specific surface area activity was calculated as 98 and 75  g COD/m2 day in the 25 and 35% reactors, respectively. Kinetic tests performed at the maximum OLR revealed that free-floating suspended biomass contributed to no more than 2.5% of the total removal. The reactors were also capable of treating br...

Cultivation of aerobic granular sludge in continuous flow under various selective pressure

Formation of aerobic granular sludge was examined in a novel continuous flow configuration, at 20 ± 1 °C. Synthetic proteinaceous wastewater with municipal primary effluent characteristics was used (i.e., COD = 370 ± 30 mg/L; TN = 43 ± 7 mg/L; and TP = 10 ± 2 mg/L). Various levels of selective pressure were applied after inoculation with flocculent sludge (i.e., estimated velocity gradients during settling between 1 and 9 1/s). Impeller rpm of 15 and below generated floccular-granular biomass, while 20 rpm and above generated large granules with a filamentous population. Effluent soluble COD, total inorganic nitrogen, and phosphate of 25 ± 7 mg/L, 11 ± 1 mg/L, and 0.1 ± 0.1 mg/L, respectively, were obtained. Observed yields were as low as 0.08-0.19 g-VSS/g-COD and whole sludge solids retention time was 18 ± 1 d. Famine conditions developed for 90% of the total aerobic volume and >45 ± 3% anaerobic substrate utilization was recorded. Aerobic granulation was demonstrated feasible under continuous flow providing adequate treatment with low biomass yields.

Attachment of anaerobic ammonium-oxidizing bacteria to augmented carrier material

ABSTRACT The formation of stable and highly active anammox biofilm is a lengthy process leading to long start-up times of deammonifying reactors of several months or more. This study aims to provide a quick solution to the problem of long start-up periods by pretreating the surface of carrier material. Two different techniques were investigated. The first one focused on growing a layer of heterotrophic biofilm on the surface of the plastic carriers prior to inoculation with anammox biomass. Specific anammox activity increased by almost 400% as compared to seed values and was equal to 250 mg NH4-N/gVSS/L•d. In the second technique, the carrier material was coated with a layer of granular-activated carbon to provide a higher surface area. The anammox activity increased by approximately 50%. In comparison, the control reactor did not develop any biofilm and no anammox activity was detected. Rapid attachment of the anammox biomass was achieved in a reactor with media that had a predeveloped layer of a biofilm. In a way, this approach is analogous to a primer or an undercoat that is put on materials before painting to ensure better adhesion of paint to the surface, hence the suggested name – bioprimer. GRAPHICAL ABSTRACT

Impact of Nanoparticle Silver in a Sequencing Batch Reactor Removing Phosphorus and Ammonia

AbstractThe effect of nanoparticle silver (AgNP) in a sequencing batch reactor (SBR) removing phosphorus and ammonia was analyzed. The amount of 500  μg/L of AgNP did not significantly change the soluble chemical oxygen demand or specific oxygen uptake rates during the batch tests. Furthermore, 300  μg/L of AgNP had no effect on phosphorus, ammonia, or chemical oxygen demand removal during continuous dosing. Analysis by inductively coupled plasma-mass spectrometry determined that the lab-scale SBR removed over 80% of influent AgNP during continuous dosing. It was also determined that the North End Water Pollution Control Centre in Winnipeg, Canada, removed just under 50% of influent AgNP, and that half of the reduction occurred before secondary treatment.

Start-up and long-term performance of anammox moving bed biofilm reactor seeded with granular biomass

Availability of granular anammox sludge is much higher than biofilm seed carriers and the sludge is easier to transport. This paper describes and investigates a formation of mature anammox biofilm originated from granular sludge and proves that an anammox moving bed biofilm reactors (MBBR) can be easily and quickly started-up by seeding with granular sludge. The reactor was fed with synthetic wastewater containing ammonium and nitrite. Successful start-up was completed in as little as 50 days when TN removal increased to more than 80%. Surface nitrogen loading rate during start-up was equal to 0.75 g m-2 d and was stepwise increased up to 5.3 g m-2 d. Biofilm thickness reached 1269 ± 444 μm at the end of the study with specific anammox activity of 22.0 ± 2.1 mg N g-1 VSS h. This study shows that granular biomass can be transitioned to a biofilm relatively easily which opens a new window of opportunity for starting-up anammox MBBRs.

Removal of Soluble Phosphorus from Surface Water using Iron (Fe-Fe) and Aluminum (Al-Al) Electrodes

The removal of soluble phosphorus using iron and aluminum electrodes was studied in water samples from the Red River, a hyper-eutrophic stream in Winnipeg, Canada. Four trials were conducted: (I) mixed batch with 150-900 mA applied for 1 min to 1 L, (II) stagnant batch with 600-900 mA applied for 1 min to 1 L, and (III and IV) continuously stirred-tank reactor with 6.25-10 min hydraulic retention times and constant 900 mA. Maximum soluble phosphorus removals of 70-80% were observed in mixed batch, and there was no significant difference between aluminum and iron electrodes (P value of 0.0526-0.9487). Aluminum electrodes performed significantly worse than iron electrodes under higher hydraulic loads, with iron removing >70% soluble phosphorus and aluminum <40% (P values of 0.0035-0.0143). The estimated cost of consumables, reported per million liters of water treated, to remove 70% soluble phosphorus from eutrophic waters with 0.35 g m-3 soluble phosphorus would include 5-17.5 USD electricity costs and material costs of 5.3-12.2 USD for iron and 39.2 USD for aluminum.

Electrocoagulation of wastewater using aluminum, iron, and magnesium electrodes

Primary influent from a municipal wastewater treatment plant was electrochemically treated with sacrificial aluminum, iron, and magnesium electrodes. The influence of sacrificial anodes on the removal of chemical oxygen demand, total nitrogen, total phosphorus, and orthophosphate during sedimentation was investigated. Nitrification kinetics were assessed on treated supernatant and biogas production was monitored on settled solids. Changes in alkalinity, conductivity, and pH were also recorded. Aluminum and iron electrodes provided high rates of orthophosphate removal (i.e., 6.8 mg-P/mmol-e). Aluminum and iron electrodes also provided similar treatment to equivalent doses of alum and ferric salts (i.e., 38-68% chemical oxygen demand, 10-13% total nitrogen, and 67-93% total phosphorus). The estimated stochiometric ratio of aluminum and iron dosed to orthophosphate removed was approximately 1.3:1 and 4.1:1, respectively. Magnesium electrodes, on the other hand, removed orthophosphate at rates 8-9 times slower than aluminum and iron (i.e., 0.9 mg-P/mmol-e). Magnesium had to be dosed at a ratio of 13.5:1 orthophosphate for phosphorus removal. Orthophosphate removal by magnesium electrodes was most likely limited by electrolysis reactions responsible for increases in pH (i.e., 0.52 pH units/mmol-e). Magnesium electrodes removed 49% chemical oxygen demand and 21% total nitrogen at the high molar ratios required for orthophosphate removal.

Kinetics of aerobic granular sludge treating low-strength synthetic wastewater at high dissolved oxygen

ABSTRACT Three parallel reactors (i.e. R1–R3) were operated with 340 mg-COD L−1, 42 mg-TN L−1, and 7 mg-TP L−1 at 20 ± 1°C. A mature granular sludge developed in 40 d and was stable for the 120 d experimentation period at an average food to microorganism ratio of 0.25 ± 0.08 g-COD g-VSS−1 d−1. Reactor biomass had higher inorganic content (i.e. 0.78–0.80 g-VSS g-TSS−1) than effluent biomass (i.e. 0.88–0.92 g-VSS g-TSS−1). Average granule diameter was 0.7–1.0 mm. Maximum phosphorus uptake and release rates averaged 4 ± 3 and 4 ± 2 mg-P g-VSS−1 h−1, respectively. Maximum observed nitrification rates averaged 1.9 ± 0.6 mg-N g-VSS−1 h−1. Phosphorus kinetics were similar between R1–R3 (i.e. P = 0.5309–0.6870) while nitrification kinetics varied significantly (i.e. P = 0.0002) even though conditions were the same. Effluent phosphate was on average 0.2 ± 0.4 mg-P L−1 while total inorganic nitrogen removal averaged 60 ± 10% resulting in an average effluent of 17 mg-N L−1. Aerobic granular sludge was capable of reliable nutrient removal from low-strength wastewater without volatile fatty acid source and at high dissolved oxygen concentrations. GRAPHICAL ABSTRACT