In the last decade, several novel and cost-effective biological nitrogen removal technologies have been developed. The discovery of anaerobic ammonium oxidation (Anammox), about 15 years ago, has resulted in new opportunities for research and development of sustainable nitrogen removal systems. Compared to conventional nitrification/denitrification, Anammox eliminates necessity of external organic carbon source, has a smaller production of excess sludge, reduces energy demand for aeration (up to 60-90%) and CO2 emissions (up to 90%). Systems based on Anammox can be of great help to comply with stricter wastewater discharge regulations and reduce environmental problems caused by nutrients discharges (e.g. eutrophication). This thesis investigates the partial nitritation/Anammox in one stage system under oxygen limited condi-tions (also called CANON or Deammonification) and with the Moving Bed Biofilm Reactor (MBBR™) technology. Anammox process coupled with partial nitritation can be particularly suitable to treat ammo-nium-rich wastewater with low content of biodegradable organic matter, such as the reject water from dewatering of digested sludge, which is usually recirculated back to the main stream of wastewater treat-ment plants, accounting for the 15-20% of the total nitrogen load. Partial nitritation/Anammox process was successfully tested on a pilot plant scale for four months at 25°C, in a 200 L Continuous Stirred Tank Reactor (CSTR), filled with 40% of Kaldnes media (model K1). At an Ammonium Surface Load (ASL) of 3.45 gN m-2d-1, the removal rate was about 2.85 gN m-2d-1. Removal efficiencies of 95%, 85% and 83% were respectively achieved for NH4+-N, inorganic nitrogen, and Total Nitrogen (TN). Bacteria activity was followed by batch tests such as Specific Anammox Activity (SAA), Oxygen Uptake Rate (OUR) and Nitrate Uptake Rate (NUR), which revealed an increase in activi-ty for Nitrosomonas and Anammox bacteria within the biofilm. Dissolved oxygen concentration in the bulk liquid was a crucial parameter, whereas pH and conductivity turned out to be two useful monitoring tools. Two laboratory-scale reactors were previously run for two months each, in order to evaluate the one-stage partial nitritation/Anammox process with a lower ASL. One reactor was fed with diluted reject water, whereas the other one treated the effluent from UASB (Up-flow Anaerobic Sludge Blanket) reactor after sand filtration. Fairly good efficiency (>75%) were reached but, however, in the last case the low ammo-nium nitrogen load could represent a problem for a stable full-scale installation and long-term growth of Anammox bacteria. Some suggestions for full-scale implementation and further research are proposed in the last chapter of this master thesis.

In recent years, the use of Anammox process for wastewater treatment has been thoroughly investigated. Currently, a major challenge is to use this process for the mainstream. The aim of this study is to find factors increasing efficiency of the deammonification process for nitrogen removal from mainstream wastewater in conditions of low ammonia concentration and low temperatures. Two types of lab-scale batch tests were done and obtained results were analysed separately. In the first lab-scale batch test suspended sludge was used and series of OUR tests were carried out. Inhibitors used during experiments were: FNA, FA, NaClO3, fresh UASB effluent and formic acid. The best results, after all tests obtained for using the free nitrous acid as an inhibitor. Results shows that NOB bacterial activity was inhibited, while AOB activity was still high. The second type of lab-scale batch test was used to check interactions between factors which have impact for the NOB suppression. Selected factors were: pH, DO and TAN and these factors were used to plan a series of experiments with MODDE application. After series of 34 experiments, results showed that this method is not effective for low concentrations of TAN and another, more efficient strategy is needed. New strategy should reduce the NOB activity or increase the activity of Anammox. It is difficult to find a good strategy to carry out this process because many factors are affecting it. Using the results, it is necessary to conduct further research, which will give indications to use the deammonification process for mainstream wastewater and will let to achieve good results.

Nitrogen removal from municipal wastewater with application of Anammox process offers cost reduction, especially if it is combined with maximal use of organic content of wastewater for biogas production. In this study a new technology is proposed, which is based on ammonium concentration from municipal wastewater by ion exchange followed by biological removal of ammonium from the concentrated stream by partial nitritation/Anammox process. In experiments on ammonium concentration four the most common ion exchange materials were tested in packed bed columns, namely strong and weak acid cation exchange resins, natural and synthetic zeolites. Experiments with synthetic wastewaters with different content and municipal wastewater showed that strong acid cation resin is the most suitable for ammonium concentration from municipal wastewater due to its high exchange capacity and fast regeneration. Since NaCl was used for regeneration of ion exchange materials, spent regenerant had elevated salinity. Experiments with activity determination showed that both nitritation and Anammox bacteria are inhibited by NaCl, where effect on Anammox bacteria is more severe. Adaptation of partial nitritation/Anammox biomass was studied using two strategies of salinity increase and it was possible to adapt the biomass to NaCl content of 10-15 g/L. The technology was tested in batch mode using strong acid cation resin for ammonium concentration from pretreated municipal wastewater, and partial nitritation/Anammox biomass for nitrogen removal from concentrated stream. It was shown that it is possible to remove 99.9% of ammonium from wastewater with ion exchange while increasing concentration of ammonium in spent regenerant by 18 times. Up to 95% of nitrogen from spent regenerant was removed by partial nitritation/Anammox biomass in batch tests. Moreover, possibilities of integrati on of the technology into municipal wastewater treatment technology, challenges and advantages were discussed. / <p>QC 20140219</p>

This thesis evaluates the performance of a deammonification system designed as a two-step tech-nology consisting of an initial partial nitritation followed by an Anammox process. Operation of a technical-scale pilot plant at the Himmerfjärden Wastewater Treatment Plant (Grödinge, Swe-den) has been assessed. Oxygen Uptake Rate (OUR) to evaluate the respiration activity of nitrifi-ers in the system and batch tests to assess reaction rates have also been applied in the study. It was found that the total inorganic nitrogen elimination strongly depended on the nitrite-to-ammonium ratio in the influent to the Anammox reactor, which was correlated with the per-formance of the partial nitritation phase. Therefore, a control strategy for oxidation of ammo-nium to nitrite has been proposed. Controlled oxygen supply to the partial nitritation reactor is obligatory to obtain a proper pH drop indicating oxidation of ammonia to nitrite at the adequate ratio. A very high nitrogen removal efficiency (an average of 84%) and stable operation of the system have been reached. Conductivity measurements were also used to monitor the system influent nitrogen load and the nitrogen removal in the Anammox reactor. The data gathered from the operation of the pilot plant enabled the use of multivariate data analysis to model the process behaviour and the assessment of the covariances between the process parameters. The options for full-scale implementation of the Anammox systems have been proposed as a result of the study. / QC 20101115

Mainstream Partial Nitritation/Anammox, also known as Mainstream Deammonification, is a promising technology for future wastewater purification that aims to remove nitrogen from wastewater in order to prevent the eutrophication. It is less costly than the traditional nitrification/denitrification process and it heads towards the direction of converting the WWTPs from energy consuming into energy producing facilities.   This Master’s thesis is based on a study regarding the nitrogen removal from mainstream wastewater. It was conducted at Hammarby Sjöstadsverk that is a research facility in the area of the Henriksdal Waste Wastewater Treatment Plant in Stockholm. Three parts of the study were developed. The main one had the purpose to evaluate the process performances of a biological pilot-scale IFAS reactor used for Mainstream Deammonification that was operated from October 2017 to March 2018. This evaluation was addressed to comprehend how the pilot-scale reactor works at different operational conditions. The remaining studies analysed the progress of the pilot-scale reactor in relation to different factors and to the settling properties of the activated sludge used in the process.   It was found that the process performances improved by changing the aeration pattern from 40 to 50 minutes for non-aeration time and from 20 to 10 minutes for aeration time and by increasing the dissolved oxygen set-point from 0.6 to 1.0 mg/L. The enhancement of the performances consisted in an inhibition of nitrite oxidizing bacteria and rise of the total nitrogen removal efficiency. In addition, anammox biofilm was observed to grow on the carriers and it was observed that the activated sludge did not have good settling properties.

Due to the adverse effects of ammonia on the environment, many governments, including Canada, have imposed new regulations to reduce the discharge of ammonia wastewater effluent into natural receiving waters, which has resulted in the upgrade of ammonia removal at water resource recovery facilities (WRRFs) across the world. There is therefore a need to investigate present urban/peri-urban and rural challenges associated with municipal total ammonia (TAN) removal. In particular, there is a need to further advance and optimize technologies such as the moving bed biofilm reactor (MBBR) to meet these critical challenges. The first objective of this thesis is to validate an elevated loaded strategy for partial nitritation (PN) MBBR as an application for mainstream urban and peri-urban municipal wastewater treatment and to elucidate the mechanism of nitrite-oxidation suppression of this system. The second objective is to identify practical storage strategies for nitrifying MBBR units as rural municipal wastewater upgrade systems (lagoon systems), optimizing the TAN removal performance during seasonal discharge periods. In the context of the present climate change crisis and sustainable development requirements, there is an increased need for efficient TAN removal from urban and peri-urban municipal wastewaters. The application of the energy and cost-efficient partial nitritation/anammox (PN/A) technology to mainstream urban and peri-urban municipal wastewater can prove challenging because of limited ability to achieve the stable PN. Hence, there is a need for the validation of the present strategies for achieving effective and stable PN in the mainstream portion of conventional urban and peri urban WRRFs. The 45 days operation of a laboratory-scale, elevated loaded PN MBBR with average surface area loading rate (SALR) of 5.2 ± 0.1 g TAN/m²·d and a hydraulic retention time of 2h showed a successful and stable nitrite accumulation. The average surface area removal rate (SARR) of 2.3 ± 0.2 g TAN/m²·d (theoretical performance objective of 2.7 g TAN/m²·d), TAN removal efficiency of 43.1 ± 3.4% (theoretical performance objective of 53%) and NO₂- / (NO₂- + NO₃-) ratio of 82.4 ± 4.8% (theoretical performance objective of 100%) meets the necessary requirement to support subsequent cost-efficient anammox process. Biofilm analyses of the laboratory-scale, elevated loaded PN MBBR indicated that the attached biofilm was thick and dense, stable biofilm that did not show and biofilm loss or washout. Biofilm cell viability analyses was indicative of an active biofilm. The ratio of AmoA gene targets of the ammonia oxidizing bacteria (AOB) in the MBBR biofilm to the targeted gene region of the Nitrospira nitrite oxidizing bacteria (NOB) population demonstrates that NOB activity suppression of this technology was the dominant mechanism of nitrite-oxidation in the elevated loaded PN MBBR system. In North America, the TAN removal performance of waste stabilization ponds (also termed wastewater treatment lagoon systems), which are widely applied as rural WRRFs, is often not stable due to seasonal temperature variations. Nitrifying MBBR as an upgrade TAN removal unit has been successfully applied to improve TAN removal during winter. However, re-seeding the nitrifying MBBR biofilm during each seasonal operation period is not sustainable. There is therefore an urgent need for optimizing storage strategies of nitrifying MBBR carriers when used as TAN removal upgrade systems of rural WRRFs. The study of storage strategies for nitrifying MBBR as lagoon upgrading systems indicated the batch storage of the nitrifying MBBR biofilms with intermittent aeration could be an effective storage strategy for short-term (12 weeks) storage. Carriers stored in continuous flow aerated condition was shown to be the second most suitable storage method for nitrifying MBBR carriers for systems exposed to less than 12 weeks of storage. Carriers stored in dry condition, batch aerated conditions without flow, and continuous flow aerated condition for long-term (over 18 weeks) failed to achieve full nitrification following 18 days of operation conditions. Carriers stored in dry condition did not successfully achieve full nitrification for short-term and long-term storage and may not be applied to store full nitrification MBBR carriers. The study suggested that, compared to re-seeding start up strategy of the lagoon upgrading nitrifying MBBR biofilm, the use of the appropriate storage strategies, such as batch aerated conditions without flow, has the potential to shorten the start-up time and save energy during the non-discharge periods.

No description available.

The presence of nutrients, such as nitrogenous compounds, in wastewater can pose serious environmental concerns to water systems leading to reduced water quality and potential risks to the public health. Nutrient removal in conventional wastewater treatment systems is becoming increasingly more costly due to the extensive energy requirements and high aeration costs. Anaerobic ammonium oxidation (Anammox) is an alternative method for nutrient removal which can reduce overall treatment costs due to less aeration requirements and less sludge production. Anammox process can be implemented with other innovative technologies, such as membrane aerated biofilm reactors (MABR) to achieve effective and sustainable nutrient removal. A major challenge associated with Anammox process is effective control of nitrite oxidizing bacteria (NOB). High temperature in wastewater treatment systems can promote Anammox bacterial growth and inhibit NOB activity. This research aims to investigate the feasibility of integrating Anammox processes with MABR technologies and to examine the effects of high temperature aeration supplied to MABR systems on Anammox bacterial growth and NOB suppression. The nitrogen removal by Anammox bacteria in a lab-scaled MABR is examined to determine the impact of aeration temperature on inhibition of NOB. / Thesis / Master of Applied Science (MASc)

New possibilities of nutrients removal by additions of magnesium compounds were studied in primary treatment and supernatant of side stream in wastewater treatment. The precipitation product from this method is magnesium ammonium phosphate (MAP) socalled struvite. High efficiencies on NH4-N and PO4-P removals have been demonstrated up to over 90 % respectively in side stream from dewatering of digested sludge. In order to find out the nutrient removal efficiency in raw wastewater and the feasibility of MAP recycling in wastewater treatment, the postulations of combining MAP and nitrification-denitrification process, and MAP and partial nitritation-anmmox process were carried out by experimental works in the laboratory at Land and Water Resources Department, KTH. It was found that 92-97 % of PO4-P and 57 % of NH4-N were removed from raw wastewater by Mg2+ addition at pH10 to pH10.5. The research work revealed that recycling of MAP by nitrification-denitrification and partial nitritation-anmmox processes may be a feasibly process combination. In MAP and nitrification -denitrification process, the released ammonium was mostly oxidized to nitrate in nitrification phase and ready for denitrification. Based on presented results on MAP and partial nitritation-anmmox process, it was found that the released ammonium was consumed by anammox bacteria.

No description available.