SHARON Process Research Articles

Nitrogen removal from low C/N wastewater in a novel Sharon&DSR (denitrifying sulfide removal) reactor

Denitrification reactions commonly remove nitrate and other reactive nitrogen (Nr) from wastewater. The C/N ratio indicates the sufficiency of organic carbons to drive heterotrophic denitrification; a low C/N ratio frequently leads to poor denitrification performance in wastewater treatment. This study proposed and tested a novel Sharon&DSR (denitrifying sulfide removal) process, with nitrite generated by the Sharon reactions and sulfide from sulfur-reducing reactions for promoting the following nitrite-based denitrification and denitrifying sulfide removal (DSR) process. The present reactor can remove nitrate at an efficiency of 97.7 %−93.5 % at an influent C/N ratio of 0.646–0.737 over a 96-d continuous-flow test. The microbial community study reveals the functional strains corresponding to individual groups of critical reactions. The stoichiometry analysis reveals the potential to apply the nitrite-based DSR process for Nr removal from ultra-low C/N (<0.64) wastewaters, experimentally demonstrated in the present study with a C/N ratio of 0.16–0.39.

A model for determination of operational conditions for successful shortcut nitrification.

Accumulation of nitrite in shortcut nitrification is influenced by several factors including dissolved oxygen concentration (DO), pH, temperature, free ammonia (FA), and free nitrous acid (FNA). In this study, a model based on minimum dissolved oxygen concentration (DOmin), minimum/maximum substrate concentration (Smin and Smax), was developed. The model evaluated the influence of pH (7-9), temperature (10-35°C), and solids retention time (SRT) (5days-infinity) on MSC values. The evaluation was conducted either by controlling total ammonium nitrogen (TAN) or total nitrite nitrogen (TNN), concentration at 50mgN/L while allowing the other to vary from 0 to 1000mgN/L. In addition, specific application for shortcut nitrification-anammox process at 10°C was analyzed. At any given operational condition, the model was able to predict if shortcut nitrification can be achieved and provide the operational DO range which is higher than the DOmin of AOB and lower than that of NOB. Furthermore, experimental data from different literature studies were taken for model simulation and the model prediction fit well the experiment. For the Sharon process, model prediction with default kinetics did not work but the model could make good prediction after adjusting the kinetic values based on the Sharon-specific kinetics reported in the literature. The model provides a method to identify feasible combinations of pH, DO, TAN, TNN, and SRT for successful shortcut nitrification.

The Combined Sharon/Anammox Process - A Sustainable Method for N-removal from Sludge Water

Wastewater treatment management, alongside many other industries, is seeking to attain a higher degree of sustainability for its processes by focusing on new technologies which minimise the consumption of resources or even recover them from the wastewater. Conventional removal of ammonium requires usually large amounts of energy for aeration and organic carbon for denitrification. This report focuses on making the nitrogen-removal process more sustainable. This can be achieved by a partial oxidation of ammonium to nitrite, after which the nitrate produced can be converted into nitrogen gas with the rest of ammonium under anoxic conditions. The treatment of nitrogen-rich water can be carried out beneficially by a combination of the Sharon process with the Anammox process. In this combined process less than 50% of the aeration energy is needed, no COD is required and an insignificant amount of sludge is produced. In this Report the potential of using this technology for the treatment of water arising from sludge treatment at a municipal wastewater treatment plant (WWTP) is evaluated and the results of the operation of the system are described in detail. This reject water contains a significant fraction of the N-load towards the wastewater treatment plant. The results are used in an economic evaluation of a potential full scale installation. The Combined Sharon/Anammox Process Report will provide an invaluable source of information for all those concerned with the efficient and sustainable treatment of wastewater including plant managers, process designers, consultants and researchers. This title belongs to Water and Wastewater Practitioner Series ISBN: 9781843390008 (Print) ISBN: 9781780402178 (eBook)

SHARON process as preliminary treatment of refinery wastewater with high organic carbon-to-nitrogen ratio

In this study, a partial nitritation reactor (SHARON, Single reactor for High activity Ammonium Removal Over Nitrite) was used to treat ammonium-rich (up to 620 mg N/L) petrochemical wastewater produced by the integrated gasification combined cycle (IGCC) and characterized also by a high organic carbon-to-nitrogen ratio (C/N, up to 1.1 gC/gN). The reactor was initially fed with a synthetic influent containing only NH4-N as substrate, then a preliminary acute toxicity test was used to assess the potential inhibiting effect of IGCC wastewater on SHARON biomass: the observed IC10, IC50, and IC90 (14.9, 54.5, and 200 mL/L, respectively) suggested a prudential operating strategy based on the gradual replacement of the synthetic medium with the IGCC wastewater. As the synthetic influent was replaced by the IGCC wastewater, the resulting influent alkalinity-to-NH4-N ratio (expressed as inorganic carbon-to-nitrogen molar ratio, Cinorg/N) influenced process performance in terms of NH4-N removal efficiency. Despite the high influent C/N ratio, when the reactor was fed only with the IGCC wastewater, the ammonium removal efficiency was as high as 53 ± 10%, the corresponding effluent NO2-N/NH4-N ratio was 1.14 ± 0.42 and nitrate production was low. The presence of the organic substrate allowed the development of heterotrophic bacteria, as indicated by the high dissolved organic carbon removal efficiency (80 ± 8%) and the low effluent C/N ratio (0.20 ± 0.04). Such reactor performance made the effluent suitable for its subsequent treatment by anammox (ANaerobic AMMonium OXidation), providing useful information about the applicability of the SHARON process for the preliminary treatment of IGCC wastewater and similar ammonium-rich industrial wastewaters with high C/N ratio.

Start-up of the SHARON and ANAMMOX process in landfill bioreactors using aerobic and anaerobic ammonium oxidising biomass

The main aim of this study is to analyse the feasibility to use aerobic ammonium oxidising bacteria (AOB) and anammox/AnAOB biomass enriched from mined municipal solid waste for in situ SHARON and ANAMMOX processes in laboratory scale landfill bioreactors (LFBR) for ammonia nitrogen removal. For this purpose, three LFBRs were operated as Control (without biomass seed), SHARON (with AOB biomass seed) and ANAMMOX (with anammox biomass seed) for 315 days. Results showed nitrogen loading rate of 1.0 kg N/d was effectively removed in SHARON and ANAMMOX LFBR. In SHARON LFBR, partial nitritation efficiency reached up to 98.5% with AOB population of MPN of 5.1 × 10(6)/mL obtained. ANAMMOX LFBR gave evolution of 95% of nitrogen gas as the end product confirmed the ANAMMOX process. Nitrogen transformations, biomass development and hydrazine and hydroxylamine formation authenticated the enriched AOB and anammox biomass activity in landfill bioreactors.

Application of SHARON Process for Leachate Treatment

Conventional nitrification-denitrification processes are used extensively for the treatment of nitrogenous compounds in leachate treatment however; it results in high operational cost due to excessive oxygen requirement. Combination of SHARON-ANAMMOX processes are among the novel nitrogen removal technologies and are promising methods for cost-effective removal of these compounds. In the scope of this study, the applicability of SHARON process for the pre-treated leachate (a lab scale anaerobic + aerobic MBR treatment) taken from Komurcuoda Leachate is investigated in a chemostat reactor. The applicability of the system is first tested using synthetic wastewater and after stable operation is achieved, diluted leachate is given to the system. The experimental results showed that influent ammonia is converted to nitrite with 52% nitritation efficiency and 40% of influent remained as ammonia. Therefore, the effluent of the SHARON system is in suitable composition to be treated in the ANAMMOX reactor.

Treatment of Effluents Polluted by Nitrogen with New Biological Technologies Based on Autotrophic Nitrification-Denitrification Processes

In recent years, various technologies have been developed for the removal of nitrogen from wastewater that is rich in nitrogen but poor in organic carbon, such as the effluents from anaerobic digesters and from certain industries. These technologies have resulted in several patents. The core of these technologies is some of the processes and patents described in this paper: Aerobic denitrification, Sharon, Anammox, OLAND, CANON, NOx process, DEMON. More specifically, one of the first innovative options described for removing nitrogen include partial nitrification under aerobic conditions (partial Sharon process) followed by autotrophic anaerobic oxidation (Anammox process). The partial Sharon-Anammox process can be performed under alternating oxic and anoxic conditions in the same bioreactor or in two steps in two separate bioreactors. This overview focuses on the technical and biological aspects of these new types of treatment system, and compares them to other technologies. Given the fact that nitrification is a sensitive process, special attention is paid to conditions such as temperature, dissolved oxygen, hydraulic retention time, free ammonia, nitrous acid concentration, and pH. A discussion of the pros and cons of such treatment systems is also included since autotrophic nitrogen removal has advantages as well as drawbacks. The paper concludes with a discussion of future research that could improve these systems by enhancing performance and reducing costs.

The SHARON process in the treatment of landfill leachate

The purpose of this paper was to study the partial nitrification of the nitrogen present in a landfill leachate applying the SHARON process in order to obtain a suitable effluent to the ANAMMOX process. As a first step, the SHARON reactor was fed anaerobically pre-treated leachate at an ammonium concentration of 2,000 mg N/L (1.1 kg N/m(3) d). In such conditions, the average ammonium and nitrite concentrations in the effluent were 775 mg N/L and 1,225 mg N/L, respectively. During this period the COD removal was very low since most of the biodegradable organic matter was removed in the anaerobic pre-treatment. Afterwards, the SHARON reactor was fed leachate without a previous treatment and the efficiency of the partial nitritation diminished. As well, the COD removal increased, achieving a percentage around 28%.

Operational strategy for a partial nitritation–sequencing batch reactor treating urban landfill leachate to achieve a stable influent for an anammox reactor

AbstractBACKGROUND: In recent years, new technologies have been developed to deal with streams with high nitrogen loads, most of them based on the anammox process. As a first step in this process, ammonium has to be partially oxidized to nitrite. This partial nitritation is usually carried out through the SHARON process. However, it can also be achieved using other configurations (sequencing batch reactor or biofilm airlift, among others). The aim of this paper is to compare two different feeding strategies (fed‐batch and step‐feed) for the operation of a partial nitritation–sequencing batch reactor (PN‐SBR) treating raw urban landfill leachate.RESULTS: A PN‐SBR treating urban landfill leachate was started up and operated using two different feeding strategies: fed‐batch and step‐feed. When the experimental results were compared, it could be seen that during the step‐feed strategy the system was more stable and presented a better performance. In addition, a cycle profile evolution of the reactor in each strategy was carried out to study the dynamics of the main chemical compounds, as well as different physical parameters. The profiles were similar for the nitrogen compounds, but with a difference in behaviour of pH, inorganic carbon and oxygen uptake ratio, which could explain the better performance and stability of the step‐feed strategy.CONCLUSIONS: This study has demonstrated that the step‐feed strategy is more suitable than the fed‐batch because it performs better overall, there is less fluctuation in its operation and it has higher effluent quality stabilization. Copyright © 2008 Society of Chemical Industry

BIOLOGICAL PHOSPHORUS REMOVAL IN A HIGH PERFORMANCE SINGLE REACTOR

The possibility of biological phosphorus removal (BPR) was studied using a lab-scale single reactor the same as SHARON process. Up to now, there has been no investigation of the feasibility of SHARON process for the purpose of phosphate removal. The optimal operation conditions were established to obtain highest removal rates. Under the experimental conditions, the phosphorus concentration dropped from an influent concentration of 1000 mg/L to levels around 0.1 mg/L or less. It was concluded that the process is efficient for the phosphorus removal from wastewater. The findings of this investigation potentially provide valuable information for the future management and remediation of phosphorus enriched wastewater and waters.

SHARON process stability modeled by BioWin

SHARON process stability modeled by BioWin

Construction, start-up and operation of a continuously aerated laboratory-scale SHARON reactor in view of coupling with an Anammox reactor

In this study practical experiences during start-up and operation of a laboratory-scale SHARON reactor are discussed, along with the construction of the reactor. Special attention is given to the start-up in view of possible toxic effects of high nitrogen concentrations (up to 4 000 mgN·&#8467;-1) on the nitrifier population and because the reactor was inoculated with sludge from an SBR reactor operated under completely different conditions. Because of these considerations, the reactor was first operated as an SBR to prevent biomass washout and to allow the selection of a strong nitrifying population. A month after the inoculation the reactor was switched to normal chemostat operation. As a result the nitrite oxidisers were washed out and only the ammonium oxidisers persisted in the reactor. In this contribution also some practical considerations concerning the operation of a continuously aerated SHARON reactor, such as mixing, evaporation and wall growth are discussed. These considerations are not trivial, since the reactor will be used for kinetic characterisation and modelling studies. Finally the performance of the SHARON reactor under different conditions is discussed in view of its coupling with an Anammox unit. Full nitrification was proven to be feasible for nitrogen loads up to 1.5 gTAN-N·&#8467;-1·d-1, indicating the possibility of the SHARON process to treat highly loaded nitrogen streams. Applying different influent concentrations led to different effluent characteristics indicating the need for proper control of the SHARON reactor. Water SA Vol.31 (3) 2005: pp.327-334

Partial nitrification to nitrite using low dissolved oxygen concentration as the main selection factor

Partial nitrification to nitrite (nitritation) can be achieved in a continuous process without sludge retention by wash out of nitrite oxidising bacteria (NOB) while retaining ammonia oxidising bacteria (AOB), at elevated temperatures (the SHARON process) and, as demonstrated in this paper, also at low dissolved oxygen (DO) concentrations. Enriched AOB was attained at a low DO concentration (0.4 mg l(-1)) and a dilution rate of 0.42 day(-1) in a continuous process. A higher oxygen affinity of AOB compared to NOB seemed critical to achieving this. This was verified by determining the oxygen half saturation constant, Ko, with similar oxygen mass transfer resistances for enriched AOB and NOB as 0.033+/-0.003 mg l(-1) and 0.43+/-0.08 mg l(-1), respectively. However, the extent of nitritation attained was found to be highly sensitive to process upsets.

A Model for the Simulation of the SHARON Process: pH as a Key Factor

The SHARON process allows partial nitrification of wastewaters with high ammonium content and, when coupled with the Anammox process, represents a more sustainable alternative for N-removal than a conventional nitrification-denitrification. In this work, a mathematical model describing a continuously aerated SHARON reactor is presented. Special attention was given to the pH, because it affects substrates availability and inhibition phenomena, implementing an algorithm for its calculation. Since ammonium-oxidizing and nitrite-oxidizing organisms are inhibited by their own substrates, ammonia and nitrous acid respectively, Haldane kinetics was used in both nitrification steps. A preliminary evaluation of the model using historical experimental data generated in a lab-scale SHARON reactor, fed with synthetic substrate, is also presented, corroborating that the quality of the obtained effluent is highly dependent on pH.

Biological Nitrogen Removal via Nitrite of Reject Water with a SBR and Chemostat SHARON/Denitrification Process

A sequencing batch reactor (SBR) and a chemostat SHARON continuous reactor were operated to develop the biological nitrogen removal via nitrite to treat real reject water with 800−900 mg of NH4+−N L-1 at laboratory scale. Methanol was added for denitrification in both reactors because of the lack of readily biodegradable chemical oxygen demand in reject water. An 8 h SBR cycle was operated with three internal aerobic/anoxic periods, maintaining the pH at 7−8 to control nitrite accumulation and alkalinity limitations in a 3 L tank, temperature was 32 °C, the hydraulic retention time was 1 day, and the solid retention time was 11 days. The SHARON process was operated in a 4 L chemostat reactor at 33 °C, where it was combined with denitrification in the same vessel with a total hydraulic retention time of 2 days using intermittent nitrification/denitrification periods of 1 h. Both systems were compared from the operational, kinetic, design, and economical points of view, giving a general conclusion that the SBR would be a slightly cheaper process (1.01 versus 1.28 euros kg-1 of N) due to the higher volumetric reaction rates. On the other hand the SHARON/denitrification reactor would be a more stable and regular process when there are fluctuations and changes in the system.

Continuity-based model interfacing for plant-wide simulation: A general approach

In plant-wide simulation studies of wastewater treatment facilities, often existing models from different origin need to be coupled. However, as these submodels are likely to contain different state variables, their coupling is not straightforward. The continuity-based interfacing method (CBIM) provides a general framework to construct model interfaces for models of wastewater systems, taking into account conservation principles. In this contribution, the CBIM approach is applied to study the effect of sludge digestion reject water treatment with a SHARON–Anammox process on a plant-wide scale. Separate models were available for the SHARON process and for the Anammox process. The Benchmark simulation model no. 2 (BSM2) is used to simulate the behaviour of the complete WWTP including sludge digestion. The CBIM approach is followed to develop three different model interfaces. At the same time, the generally applicable CBIM approach was further refined and particular issues when coupling models in which pH is considered as a state variable, are pointed out.

Controlling the nitrite:ammonium ratio in a SHARON reactor in view of its coupling with an Anammox process

The combined SHARON-Anammox process for treating wastewater streams with high ammonia load is the focus of this paper. In particular, partial nitritation in the SHARON reactor should be performed to such an extent that a nitrite:ammonium ratio is generated which is optimal for full conversion in an Anammox process. In the simulation studies performed in this contribution, the nitrite:ammonium ratio produced in a SHARON process with fixed volume, as well as its effect on the subsequent Anammox process, is examined for realistic influent conditions and considering both direct and indirect pH effects on the SHARON process. Several possible operating modes for the SHARON reactor, differing in control strategies for O2, pH and the produced nitrite:ammonium ratio and based on regulating the air flow rate and/or acid/base addition, are systematically evaluated. The results are quantified through an operating cost index. Best results are obtained by means of cascade feedback control of the SHARON effluent nitrite:ammonium ratio through setting an O2 set-point that is tracked by adjusting the air flow rate, combined with single loop pH control through acid/base addition.

Full-Scale Experience with the Sharon Process through the Eyes of the Operators

Full-Scale Experience with the Sharon Process through the Eyes of the OperatorsThis paper summarizes different operating aspects and experiences of several SHARON plants. The SHARON process is suitable for treatment of high strength ammonia wastewaters such as reject water from dewatering of digested sewage sludge and wastewater from sludge drying or incineration plants. The aerated retention time and nitrite concentration are the two most important process parameters to...Author(s)J.W. MulderJ.O.J. DuinJ. GoverdeW.G. PoieszH.M. van VeldhuizenR. van KempenP. RoeleveldSourceProceedings of the Water Environment FederationSubjectSession 67: Municipal Wastewater Treatment Processes: Side-Stream Treatment of NRich Sludge Return Liquors – A Bounty of Full-Scale Proven TechnologiesDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2006ISSN1938-6478SICI1938-6478(20060101)2006:7L.5256;1-DOI10.2175/193864706783763444Volume / Issue2006 / 7Content sourceWEFTECFirst / last page(s)5256 - 5270Copyright2006Word count206

Nitrogen removal from piggery waste using the combined SHARON and ANAMMOX process

Nitrogen removal in piggery waste was investigated with the combined SHARON-ANAMMOX process. The piggery waste was characterized as strong nitrogenous wastewater with very low C/N ratio. For the preceding SHARON reactor, ammonium nitrogen loading and conversion rates were 0.97 kg NH4-N/m3 reactor/day and 0.73 kg NH4-N/m3 reactor/day, respectively. Alkalinity consumption for ammonium conversion was 8.5 gr bicarbonate utilized per gram ammonium nitrogen converted to NO2-N or NO3-N at steady-states operation. The successive ANAMMOX reactor was fed with the effluent from SHARON reactor. Nitrogen loading and conversion rates were 1.36 kg soluble N/m3 reactor/day and 0.72 kg soluble N/m3 reactor/day, respectively. The average NO2-N/NH4-N removal ratio by ANAMMOX reaction was 2.13. It has been observed that Candidatus "Kuenenia stuttgartiensis" were dominated in the ANAMMOX reactor based on FISH analysis.

Coupling the SHARON process with Anammox: Model-based scenario analysis with focus on operating costs

The combined SHARON-Anammox process for treating wastewater streams with high ammonia concentration is discussed. Partial nitritation in the SHARON reactor should be performed to such an extent that an Anammox-optimal nitrite:ammonium ratio is generated. The SHARON process is typically applied to sludge digestion rejection water in order to relieve the ammonium load recycled to the main plant. A simulation study for realistic influent conditions on a SHARON reactor with a fixed volume and operated with constant air flow rate reveals that the actual nitrite:ammonium ratio might deviate significantly from the ideal ratio and might endanger operation of the subsequent Anammox reactor. It is further examined how the nitrite:ammonium ratio might be optimized. A cascade pH control strategy and a cascade O2 control strategy are tested. Simulation results are presented and the performance of the different strategies is assessed and quantified in an economic way by means of an operating cost index. Best results are obtained by means of cascade feedback control of the SHARON effluent nitrite:ammonium ratio through setting an O2-set-point that is tracked by adjusting the air flow rate.