Inaug.-diss.--Göttingen. / Lebenslauf.

Thesis (Ph.D.)--University of Delaware, 2005. / Principal faculty advisor: Daniel K. Cha, Dept. of Civil & Environmental Engineering. Includes bibliographical references.

No description available.

The purpose of using chemical nitrification inhibitors is to delay the oxidation of ammoniacal fertilizers during the early part of the growing season in order to minimize N losses prior to the period of maximum crop uptake. Since NH₄⁺ is electrostatically attracted to soil particles, leaching losses would be minimized, and denitrification losses could not occur in the absence of NO₃⁻. Thus, smaller amounts of fertilizer N would be required, resulting in lower inputs of money and energy as well as less potential for environmental pollution. A study (Chapter Two) was initiated in the fall of 1977 to determine if ATC could minimize overwinter losses of fall-applied N. Urea (200 kg N/ha) with or without a 1% coating: of ATC (4-amino-l,2,4-triazole) was banded or broadcast onto a silt soil on November 8, when the soil temperature at 10 cm depth was 1.9°C. The soil was sampled to a depth of 90 cm at approximately one month intervals until April, and NH₄⁺ and NO₃⁻ were determined. In the banded plots, some nitrification occurred prior to January, but from this date unti1 March there was very little change in soil NH₄⁺ levels. Overall, from December to April, there were 70 and 48% decreases in the 0-15 cm plots without and with ATC, respectively. In all the broadcast plots, regardless of ATC treatment, nitrification proceeded steadily throughout the sampling period, with 93 and 85% decreases from the December 0-15 cm NH₄⁺ levels in the non-ATC and ATC plots, respectively. It is concluded that ATC is partially effective in minimizing N losses when applied in the fall as a band with urea, but when broadcast there is no effect on nitrification. Leaching of the water-soluble ATC was the likely cause of its poor effectiveness. Significant leaching of urea from the zone of application was also found to occur during the first month following its application. A laboratory study (Chapter Three) was conducted to determine the influence of the nitrification inhibitors ATC and N-Serve [2-chloro-6-(trichloromethyl)-pyridine] on urea hydrolysis in a silt soil at 2 and 12°C. There was no delay of ureolysis caused by the presence of these chemicals, even at 20 times the recommended application rate. At 2°C the rate of hydrolysis was about half that at 12°C, with 21 and 7 days being required for complete hydrolysis at 2 and 12°C, respectively. These results suggest that leaching of urea may occur following its application to a cold soil during periods of heavy precipitation as was found in the winter nitrification study (Chapter Two). A series of field experiments (Chapter Four) was conducted with silage corn (Zea mays L.) to compare the effectiveness of the nitrification inhibitors ATC and N-Serve in a loamy sand and a silt. Urea was coated with the inhibitors at a rate of 1% of active ingredient per weight of N and applied as a band or broadcast in the spring of 1977 and 1978. Neither inhibitor significantly affected nitrification when applied as a broadcast treatment to either soil. In the silt, both inhibitors were equally effective in delaying nitrification when banded, whereas in the loamy sand ATC was much more effective than N-Serve. The effectiveness of N-Serve persisted much longer in the silt (86 days) than in the loamy sand (23 days). This suggested that volatilization of N-Serve severely limited its effectiveness in the loamy sand. There was no significant improvement in crop yields or N content due to inhibitor treatment in either soil. / Land and Food Systems, Faculty of / Graduate

The new Canadian federal wastewater regulations, which restricts the release of ammonia from treated wastewaters, has resulted in upgrade initiatives at many water resource recovery facilities across the country to reduce the discharge of ammonia into our natural waters. The objective of this dissertation is therefore to investigate and optimize the performance of two attached growth technologies for rural and peri-urban/urban municipal ammonia removal. In particular, the first specific objective of this dissertation is to investigate the performance and microbial response of the BioCord technology as an upgrade system for the post-carbon removal nitrification of rural wastewaters. The second specific objective is to study the start-up of an attached growth anammox technology to enhance current knowledge pertaining to anammox biofilm attachment, growth and maturation. The results pertaining to the first specific objective of this research, a study of the design and optimization of the BioCord technology, demonstrates a recommended design rate for the post-carbon removal, nitrifying BioCord system of a surface area loading rate (SALR) of 1.6 NH4⁺-N/m²·d and up to 1.8 NH4⁺-N/m²·d with steady ammonia-nitrogen removal efficiencies greater than 90% and steady and low solids production rate up to 0.26 g TSS/d. A loss of system stability and biofilm sloughing, identified as fluctuating ammonia removal rates and solids production rates, were observed at elevated SALRs of 2.1 and 2.4 g -N/m²·d. The microbial results indicate that the meso-scale structure of the biofilm and the micro-animal population are directly affected by operational conditions. Enhanced air scouring configuration is shown to be a potential optimization strategy to prevent the clogging of biofilm pores and improve the system stability in terms of solids production rate in the BioCord technology. The results pertaining to the second specific objective of this research, the study of inoculation and carrier modification strategies for the rapid start-up of attached growth anammox technology, demonstrates significantly higher kinetics, faster biofilm growth and greater anammox bacteria enrichment on the silica-functionalized carriers and pre-seeded denitrifying carriers in a system inoculated with detached anammox biofilm mass during the early stages of attachment and growth of start-up. The study suggests that the use of the silica-functionalized and pre-seeded denitrifying carriers along with detached anammox biofilm inoculation has the potential to accelerate the anammox biofilm attachment, growth and maturation.

The wastewater treated at the Hopewell Regional Wastewater Treatment Facility (HRWTF) is very unique both because it is comprised of effluents of seven different industries in the area in addition to the domestic wastewater in the area, and because it reaches high temperatures in the basins, often above 45oC during the summer. Four different bench scale systems consisting of continuously stirred tank reactors (CSTRs) in series were operated during the summer of 1997 to quickly assess the feasibility of nitrifying and denitrifying the total flow at HRWTF down to a final effluent total nitrogen concentration of 10 mg-N/L or less. The four main treatment strategies tested were: aerobic/anoxic treatment of the final effluent of HRWTF at moderate temperatures (approximately 30oC); anaerobic/anoxic/aerobic (A2/O) treatment of the primary effluent of HRWTF at moderate temperatures; treatment of the effluent of one of the industries which had a high ammonia wastewater and which was originally believed to contain nitrification inhibitors; and fully aerobic treatment of the primary effluent of HRWTF at high temperatures (of approximately 40 to 45oC) with an activated sludge gradually acclimated to such temperatures over the course of two months. At the end of the study, a two-week high temperature study was conducted on the system which had been treating the secondary effluent all summer with the same activated sludge which was acclimated only to temperatures around 30oC. The fully aerobic high temperature system which had been nitrifying the primary effluent all summer was converted to a modified Lutzack-Ettinger (MLE) process at the end of the study to test whether the primary effluent could be denitrified as well as nitrified at high temperatures with the sludge acclimated to high temperatures. All four of the main treatment strategies demonstrated that nitrification and denitrification of either the total flow or the high ammonia side stream could be achieved down to the desired total nitrogen concentrations. The high temperature study conducted on the system which had been treating the secondary effluent all summer indicated that the sudden increase from approximately 30oC to approximately 40oC over a twenty-four hour period, similar to the sudden temperature increase which occurs every spring at HRWTF, quickly ends nitrification in a system not acclimated to high temperatures, while denitrification and COD removal is hardly affected by such a temperature change. While the nitrification performance of the gradually acclimated system treating the primary effluent at high temperatures was adequate, problems maintaining a consistent MLVSS or ETSS concentration suggested that the high temperatures seen in the basins at HRWTF are likely to make consistent treatment difficult. As a result of considering both capital cost requirements and quality of treatment, the bench scale testing suggested that the most likely candidates for successful treatment of the total flow down to desired total nitrogen concentrations would involve either the A2/O treatment of the primary effluent of HRWTF, possibly with the addition of a cooling tower, or A2/O treatment of the high ammonia side stream, possibly involving the dilution of the wastewater with one of the other flows sent to HRWTF. It was concluded that pilot scale evaluation of the two options was required for a final design decision, and pilot scale evaluation was being performed when this thesis was completed. / Master of Science

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The Hampton Roads Sanitation District (HRSD) operates thirteen treatment plants in the eastern Virginia area with a combined capacity of 231 million gallons per day (mgd). The Nansemond Treatment Plant (NTP) is one of the larger facilities, and is designed to treat 30 mgd using a 3-stage Virginia Initiative Process (VIP) biological nutrient removal (BNR) process. The majority of the influent is domestic, but there is also a large industrial contribution, particularly from a hog processing facility, landfill leachate, and significant loads from septage and grease deliveries (Bilyk et al, 2008). NTP is currently being upgraded to a 5-stage Bardenpho process to achieve improved total nitrogen (TN) removal. For several years starting in about 2001, NTP has experienced continuous and sporadic nitrification upsets that cannot be explained by plant operations events. Sporadic nitrification upsets are characterized by sharp increases in effluent ammonia and nitrite with decreases in nitrate concentrations due to reduced growth rates in bacteria. The result is reduced overall total nitrogen (TN) removal. Continuous inhibition is evidenced by a previous engineering report by Hazen and Sawyer, P.C. (2007), whereby it was suggested that the ammonia oxidizing bacteria (AOB) maximum specific growth rate (μmax) be reduced from 0.9 to 0.57 days-1. This has significant implications in terms of the required aeration volume for consistent nitrification at cold temperatures. The objective of this project was to determine whether the NTP influent wastewater does in fact exhibit inhibition to ammonia (AOB) and nitrite oxidizing bacteria (NOB), evaluated independently, and to determine the impact on polyphosphate accumulating organism activity (PAO). Because the historical operational experiences and data analysis suggested inhibited AOB and NOB activity, an investigation was initiated targeting the source of that inhibition. After conducting seventeen weeks of batch experiments the source of inhibition was not determined. Batch experiments however, did reveal other possible sources of inhibition including large amounts of chemical toilet waste received at NTP possibly containing quaternary ammonium compounds (QACs). Due to available blower capacity during construction it was planned that nitrification would not be maintained during the fall of 2009. In an effort to stop nitrification, the solids retention time (SRT) was purposely reduced over a period of about one month (as wastewater temperature cooled) until additional blower capacity was available. This provided an opportunity to study baseline nitrification kinetics and determine the potential for continuous inhibition through profile sampling. Simulation modeling of the profile sampling and plant data was performed with Biowin 3.1 (EnviroSim, Ltd.) as a means for comparison and to generate μmax values for AOB to compare with the original design μmax of 0.57-1. Profile sampling was conducted from the primary effluent to the secondary effluent with samples collected along the length of the BNR process. This was being done to address the following issues: • Conduct baseline sampling prior to a more detailed nitrification inhibition study estimated to begin in May 2010, which will include influent sampling and the operation of bench-scale sequencing batch reactors. This will be used to establish "normal" COD, nutrient and DO profiles though the VIP process without (and possibly with) the impact of inhibitory conditions, specifically with respect to N conversions and P release and uptake along the process. • Evaluate the potential for nitrite accumulation in the process and its potential effect on aerobic phosphate uptake by phosphorus accumulating organisms (PAOs). • Evaluate the impact of sporadic ferric chloride addition to the biological process as a means of preventing effluent TP exceedances. • Evaluate the design μmax to the actual observed μmax for AOB through simulation modeling. • Compare modeling and observed profile data for signs of any continuous nitrification inhibition. Experimental results from batch-rate testing confirmed the sporadically inhibitory nature of NTP primary effluent when combined with other stable nitrifying biomasses. Investigation into quaternary ammonium compounds (QACs) which were contained in the chemical toilet waste suggested that QACs at higher concentrations caused some inhibition of NOB activity, but no significant impact on AOB activity. Profile sampling demonstrated no signs of sporadic or continuous nitrification inhibition or impact of nitrite accumulation and ferric chloride addition on biological treatment processes. Modeling of the profile data generated similar profiles; however, there were slight variations as the model predicted nitrification to stop earlier than what was actually observed. From the modeling it was also determined that the maximum specific growth rate (μmax) of ammonia oxidizing bacteria (AOB) was in the range of 0.50 – 60 days-1. This supported batch and profile work that showed NTP PE exhibited some degree of continuous inhibition. Diurnal loadings however, were not accounted for in the modeling which could slightly underestimate the actual AOB μmax value. Several suspected inhibitors were eliminated as potential causes of inhibition, including waste from a hog processing facility, landfill leachate, the addition of ferric chloride, plant internal recycle streams, branches of the collection system, and chemical toilet disinfectants containing QACs. References Bilyk, K., Cubbage, L., Stone, A., Pitt, P., Dano, J., and Balzer, B. 2008. Unlocking the Mystery of Biological Phosphorus Removal Upsets and Inhibited Nitrification at a 30 mgd BNR Facility. Proceedings of the Water Environment Federation Technical Conference and Exposition, 2008. Hazen and Sawyer. 2007. Nansemond Treatment Plant Nutrient Reduction Improvement Technical Memorandum. / Master of Science