Biological Removal Of Ammonia Research Articles

Genomic insights into heterotrophic nitrifying-aerobic denitrifying bacteria from petroleum terminal effluents

Heterotrophic nitrification-aerobic denitrification (HN/AD) is a single-organism process that converts ammonia into nitrogen gas under strictly aerobic conditions, playing a crucial role in biological ammonia removal from industrial wastewater. Despite several studies, significant knowledge gaps remain about the genes involved in the process. This study aimed to characterize the genomes of four HN/AD bacterial strains, Pseudomonas stutzeri UFV5, Pseudomonas balearica UFV3, Rhodococcus ruber UFV2, and Gordonia amicalis UFV4, and identify potential genes involved in the HN/AD process. Results revealed that shared genes of these strains were primarily involved in amino acid and protein biosynthesis. The two Pseudomonas strains had more genes linked to nitrogen metabolism than the others. Additionally, four strains showed a significant number of hypothetical proteins and genes related to oxidative stress. Notably, no common nitrogen metabolism genes were found among the strains, indicating a lack of a shared HN/AD pathway. However, comparing these genomes with previous transcriptomic data of the P. stutzeri UFV5 identified nine shared proteins as potential HN/AD pathway candidates. This study enhances our understanding of the genomes of these HN/AD-capable bacterial strains and identifies nine candidate genes as markers for the HN/AD process.

Selection, Identification and Functional Performance of Ammonia-Degrading Microbial Communities from an Activated Sludge for Landfill Leachate Treatment.

The increasing amounts of municipal solid waste and their management in landfills caused an increase in the production of leachate, a liquid formed by the percolation of rainwater through the waste. Leachate creates serious problems to municipal wastewater treatment plants; indeed, its high levels of ammonia are toxic for bacterial cells and drastically reduce the biological removal of nitrogen by activated sludge. In the present work, we studied, using a metagenomic approach based on next-generation sequencing (NGS), the microbial composition of sludge in the municipal wastewater treatment plant of Porto Sant'Elpidio (Italy). Through activated sludge enrichment experiments based on the Repetitive Re-Inoculum Assay, we were able to select and identify a minimal bacterial community capable of degrading high concentrations of ammonium (NH4+-N ≅ 350 mg/L) present in a leachate-based medium. The analysis of NGS data suggests that seven families of bacteria (Alcaligenaceae, Nitrosomonadaceae, Caulobacteraceae, Xanthomonadaceae, Rhodanobacteraceae, Comamonadaceae and Chitinophagaceae) are mainly responsible for ammonia oxidation. Furthermore, we isolated from the enriched sludge three genera (Klebsiella sp., Castellaniella sp. and Acinetobacter sp.) capable of heterotrophic nitrification coupled with aerobic denitrification. These bacteria released a trace amount of both nitrite and nitrate possibly transforming ammonia into gaseous nitrogen. Our findings represent the starting point to produce an optimized microorganisms's mixture for the biological removal of ammonia contained in leachate.

Ammonia-oxidizing microbes and biological ammonia removal in drinking water treatment

Ammonia in drinking water can lead to formation of disinfection byproducts in disinfection and bacteria regrowth in water distribution systems. Biological ammonia removal is an economical and environment-friendly way in controlling ammonia.

Performance analysis of four-stage rotating biological contactor in nitrification and COD removal from petroleum refinery wastewater

The petroleum refining process generates large quantities of wastewater that discharge of untreated wastewater into water bodies results in environmental and human health effects due to the release of toxic containments. In this study, the biological removal of ammonia from petroleum refinery wastewater in a bench-scale rotating biological contactor (RBC) under continuous operation was investigated. The experiments were conducted base on a central composite design to evaluate the effect of four significant independent variables on the performance of the system. Response surface methodology was applied to minimize the number of runs and investigating the interactive effects of variables on ammonia and chemical oxygen demand (COD) removals. The RBC was operated at different hydraulic loading rates of 0.005, 0.008, and 0.016 m3/m2d. The optimum conditions were the temperature of 32.19 °C, influent ammonia concentration of 20.54 mg/l, the flow rate of 5.57 mL/min, and discs rotational speed of 4.58 rpm for ammonia and COD removal efficiency simultaneously. The maximum removal efficiency of ammonia and COD were obtained at 99.07 % and 85.76 % respectively. Finally, our results suggest that RBC may be considered as a promising method for petroleum refinery wastewater treatment, especially in simultaneously COD and ammonia removal.

Simultaneous Stripping of Ammonia from Leachate: Experimental Insights and Key Microbial Players

Air stripping is commonly used to remove the ammonia in multistage treatment systems for municipal landfill leachate (LFL). This paper proposes a novel approach combining the process of stripping with biological removal of ammonia, based on simultaneous nitrification and denitrification (SND) in a single hybrid sequencing batch reactor (HSBR). To avoid the accumulation of free ammonia (N-FAN), the shallow aeration system was used for the treatment of raw LFL with N-TAN level of 1520 mg/L and pH 9.24. The mean N-FAN removal efficiency of 69% with the reaction rate of 55 mg L−1 h−1 and mean ammonium (N-NH4+) removal efficiency of 84% with the reaction rate of 44 mg L−1 h−1 were achieved within a month in such an HSBR (R1). The comparative HSBR (R2), with conventional aeration system maintaining the same concentration of dissolved oxygen (DO ≤ 1 mg/L), was removing only trace amounts of N-FAN and 48% of N-NH4+. The quantitative analysis of 16S rRNA genes indicated that the number of total bacteria, Actinobacteria, Bacteroidetes, Firmicutes, and Beta- and Gammaproteobacteria increased during the operation of both HSBRs, but was always higher in R1. Moreover, the bacterial community shift was observed since the beginning of the experiment; the relative abundance of Firmicutes, and Beta- and Gammaproteobacteria increased by 5.01, 3.25 and 9.67% respectively, whilst the abundance of Bacteroidetes and Actinobacteria decreased by 15.59 and 0.95%. All of the surveyed bacteria groups, except Gammaproteobacteria, correlated significantly negatively (p < 0.001) with the concentrations of N-NH4+ in the outflows from R1. The results allow us to suppose that simultaneous stripping and SND in a single reactor could be a promising, cost-effective and easy-to-operate solution for LFL treatment.

Screening Heterotrophic Ammonia Removal and Aerobic Denitrifying Bacteria from Wastewater of Ammonia Production Units of a Petrochemical Industry.

Petrochemical wastewaters have high ammonium contents that can cause serious environmental pollutions. Among different treatment methods, biological ammonia removal using bacteria has been attracted more attention due to their environmental friendly and high efficiency. The aim of the present study was to isolate heterotrophic nitrogen removal and aerobic denitrifying bacteria from petrochemical wastewater to be used for bioremediation. Wastewater and sludge samples were prepared and their chemical parameters were analyzed. Bacterial isolation was done through enrichment in mineral salt medium and basal salt medium and identified through 16S rRNA gene sequencing. The ability of isolates was evaluated at different concentrations of ammonia, nitrate, and carbon sources and at different time intervals. As a result, ten bacterial isolates were obtained that 5 strains were identified as heterotrophic nitrogen removal bacteria and 5 strains were able to do aerobic denitrification. From these, Pseudomonas guguanensis strain 4-n-1 with 93.2% ammonia removal during 24h at 40mg/L ammonium sulfate concentration and Pseudomonas guariconensis strain 5-d-1 with 89.2% denitrification during 24h at 100mg/L nitrate concentration were the best isolates. Finally, based on the efficiency of these isolates it can be concluded that effective ammonia removal can be achieved using these species as consortium and simultaneous heterotrophic nitrogen removal with aerobic denitrification is suitable method for efficient ammonium removal from petrochemical wastewater and reduction of ammonia concentration.

Optimal conditions for the biological removal of ammonia from wastewater of a petrochemical plant using the response surface methodology

High concentrations of nitrogen compounds, such as ammonia observed in the petrochemical industry, are the major environmental pollutants. Therefore, effective and inexpensive methods are needed for its treatment. Biological treatment of various pollutants is a low cost and biocompatible replacement for current physico-chemical systems. The use of aquatic plants is an effective way to absorb the nutrient pollutants. In this study, the optimal operating conditions in the biological removal of ammonia from the urea-ammonia wastewater of Kermanshah Petrochemical Company by Lemna gibba were determined using the response surface methodology. Lemna gibba was collected from the ponds around Kermanshah and maintained in a nutrient medium. Effect of the main operational variables such as ammonia concentration, residence time and Lemna gibba to surface ratio on optimal conditions of ammonia removal from wastewater has been analyzed using the Box-Behnken model design of experiments. Model numerical optimization was performed to achieve the maximum amount of ammonia removal from wastewater. The ammonia removal percentage varied from 13% to 88%, but the maximum amount of ammonia removal was determined at ammonia concentration of 5 ppm and Lemna gibba residence time of 11 days in wastewater based on the quadratic model. Lemna gibba to surface ratio of 2:5 was measured at 96.449%. After optimization, validation of ammonia removal was performed under optimum conditions and measured at 92.07%. Based on the experimental design and the predicted under model conditions, the maximum amounts of ammonia removal percentage in the experiments were 82.84% and 88.33% respectively, indicating the high accuracy of the model to determine the optimum conditions for the ammonia removal from wastewater.

Biological Removal of Ammonia from Municipal Landfill Leachate (Kozodrza, Poland) at Limited Oxygen Access and Presence of Kaldnes Media

Biological Removal of Ammonia from Municipal Landfill Leachate (Kozodrza, Poland) at Limited Oxygen Access and Presence of Kaldnes Media

Combining magnesium ammonium phosphate precipitation with membrane processes for ammonia removal from methanogenic leachates

AbstractChemical precipitation of ammonia as magnesium ammonium phosphate (MAP) from methanogenic leachates can be a competitive alternative to biological ammonia removal. Potential for trading of the precipitate as a fertiliser defines the economics of the process. The precipitate from a landfill leachate often containing organics and heavy metals as impurities with unknown risks limits its possibility for agricultural use. This study combines MAP precipitation with membrane processes and investigates the influence of wastewater matrix, solution pH and dosage ratio of chemicals (Mg2+ : ) on the precipitate purity through lab scale semibatch experiments. Under similar experimental conditions (pH 8.5 and 1 : 1 Mg2+ : molar dosage), the precipitates from raw leachate and nanofiltration (NF) permeate showed MAP contents of 65 and 90%, respectively, correspondingly with about 8300 and 1600 mg TOC/kgprecipitate. For precipitation from NF permeate, precipitation at pH 8.0 with 1 : 1 dosage ratio and pH 8.5 with 1 : 0.9 dosage ratio gave precipitates each with about 97% purity.

Biological ammonia removal field studies for drinking water treatment

In order to study the applicability of biological ammonia removal from drinking water, field experiments with 10 L/h flow rate were carried out at a case-study area, where raw water contained arsenic, iron, manganese, dissolved gases (methane, aggressive carbon dioxide) and ammonia. The technology applied at the waterworks consisted of potassium permanganate (KMnO4) dosing and rapid sand filtration followed by sodium hypochlorite (NaOCl) disinfection. The treated water fulfilled the requirements for iron, arsenic and usually for manganese as well; however, it contained ammonia and dissolved gases. The aim of the investigation was to find out how the current technology could be modified in order to meet the drinking water requirements. In the first experimental setup, treated water of the waterworks was aerated and directed to the biological reactor, where ammonia was converted into nitrate. In the second experimental setup, the untreated water was first aerated, followed by a biological reactor (sand filter), KMnO4 dosing and a second sand filtration stage. Both experiments were successful; the treated water fulfilled the iron, manganese, arsenic and ammonia limits. Furthermore, the studied technologies were capable of removing dissolved gases. Modification of the current technology according to the second experimental setup is suggested, for two reasons: the KMnO4 dose could be decreased to one-third of the current value, and the explosive methane gas could be removed in the first treatment step.

Effect of Influent COD on Biological Ammonia Removal Efficiency

Effect of Influent COD on Biological Ammonia Removal Efficiency

Ammonia biofiltration and community analysis of ammonia-oxidizing bacteria in biofilters

Biological removal of ammonia was investigated using compost and sludge as packing materials in laboratory-scale biofilters. The aim of this study is to characterize the composition of ammonia-oxidizing bacteria (AOB) in two biofilters designed to remove ammonia. Experimental tests and measurements included analysis of removal efficiency and metabolic products. The inlet concentration of ammonia applied was 20–100 mg m −3. Removal efficiencies of BFC and BFS were in the range of 97–99% and 95–99%, respectively. Periodic analysis of the biofilter packing materials showed ammonia was removed from air stream by nitrification and by the improved absorption of NH 3 in the resultant acidity. Nitrate was the dominant product of NH 3 transformation. Changes in the composition of AOB were examined by using nested PCR, denaturing gradient gel electrophoresis (DGGE) and sequencing of DGGE bands. DGGE analysis of biofilter samples revealed that shifts in the community structure of AOB were observed in the experiment; however, the idle phase did not cause the structural shift of AOB. Phylogenetic analysis revealed the population of AOB showed Nitrosospira sp. remains the predominant population in BFC, while Nitrosomonas sp. is the predominant population in BFS.

Simultaneous biological removal of ammonia, iron and manganese from potable water using a trickling filter

A pilot-scale trickling filter with dual layer support material was constructed and tested for simultaneous biological removal of ammonia, iron and manganese from potable water. The performance of the trickling filter was tested at constant hydraulic loading of 226 m 3/m 2 d while feed concentrations of iron, ammonia and manganese were varied between 0.5 and 4.0, 0.5 and 3.0, and 0.5 and 1.3 mg/l, respectively. The system was inoculated with a mixed culture and a series of experiments was performed to investigate the interactions among ammonia, iron and manganese removal when simultaneously present in the trickling filter. The oxidation reduction potential increased along the filter depth from about 150 to 600 mV, depending on the feed concentrations, thus enabling one-stage simultaneous removal of the three pollutants. Ammonia and iron drastically affected manganese oxidation and manganese was found to be the rate-limiting pollutant. The results are presented using an operating diagram of the system, that determines the range of operating conditions resulting in optimal operation, keeping iron, ammonia and manganese concentration under the maximum permitted limits in potable water.

Ammonia, iron and manganese removal from potable water using trickling filters

Pilot scale trickling filters were constructed and tested in order to study biological removal of ammonia, iron and manganese from potable water. The effect of the size of the support material on nitrification performance was studied extensively. The mean size of the gravel and hence, the specific surface area was found to be critical for optimal nitrification operation. A steady-state model developed in previous work was used to predict filter's performance. The model was very accurate only for the gravel size for which maximum nitrification rates were observed. The effect of the operational conditions on the physico-chemical and combined physico-chemical and biological iron oxidation was also studied. It was found that the contribution of biological oxidation is significant, increasing filter's efficiency by about 6% and reducing the required filter depth by about 40%. Manganese biological removal was studied using gravel with small mean diameter, thus providing high specific surface area. Feed concentrations up to 4.0 mg/l were treated sufficiently. Finally, experiments were performed to investigate the simultaneous removal of ammonia, iron and manganese. Experimental results showed that the combined, as well as the simultaneous removal of the aforementioned pollutants, can be achieved by single-step filtration.

Long-term operation of biofilters for biological removal of ammonia

Biological removal of ammonia was investigated using two types of packing materials, compost and sludge in laboratory-scale biofilters (8 l reactor volume). The aim of this study is to investigate the potential of unit systems packed with these supports in terms of ammonia emissions treatment. Experimental tests and measurements included analysis of removal efficiency, metabolic products, and results of long-term operation. The inlet concentration of ammonia applied was 20–200 mg m −3. The ammonia loading rates of 24.9–566 g NH 3 m −3 d −1 to compost biofilter (BF3) and 24.9–472 g NH 3 m −3 d −1 to sludge biofilter (BF4) were applied for 210 days, respectively. Removal efficiencies of the compost and sludge biofilters were in the range of 97–99% and 95–99%, respectively when the inlet concentration of ammonia was below 110 mg m −3, and the maximum elimination capacities were 288 and 243 g NH 3 m −3 d −1, respectively. However, removal efficiency and elimination capacity of both biofilters significantly decreased as the inlet concentration increased to above 110 mg m −3. By using kinetic analysis, the maximum removal rate of ammonia, V m, and the saturation constant, K s, were determined for both packing materials and the value of V m for compost was found to be larger. Periodic analysis of the biofilter packing materials showed the accumulation of the nitrification product NO 3 - in the operation. During the experiment, the pressure drops measured were very low. The use of both packing materials requires neither nutritive aqueous solution nor buffer solution.

Removal of Ammonia by Biofilters: A Study with Flow-Modified System and Kinetics

The characteristics of ammonia removal by two types of biofilter (a standard biofilter with vertical gas flow and a modified biofilter with horizontal gas flow) were investigated. A mixture of organic materials such as compost, bark, and peat was used as the biofilter media based on the small-scale column test for media selection. Complete removal capacity, defined as the maximum inlet load of ammonia that was completely removed, was obtained. The modified biofilter showed complete removal up to 1.0 g N/kg dry material/day. However, the removal capacity of the standard biofilter started to deviate from complete removal around 0.4 g N/kg dry material/day, indicating that the modified biofilter system has higher removal efficiency than the standard upflow one. In kinetic analysis of the biological removal of ammonia in each biofilter system, the maximum removal rate, V m , was 0.93 g N/kg dry material/day and the saturation constant, K s , was 32.55 ppm in the standard biofilter. On the other hand, the values of V m and K s were 1.66 g N/kg dry material/day and 74.25 ppm, respectively, in the modified biofilter system.

Biological ammonia removal from anaerobically pre-treated landfill leachate in sequencing batch reactors (SBR)

The aim of the study was to investigate both the use of the SBR technology in biological ammonia removal from landfill leachate, and the suitability of raw landfill leachate as external carbon source in denitrification step. The SBR was fed with diluted leachate for the first 42 days and then the effluent of UASBR was used as the feed. The SBR was operated intermittently with a cycle time of 24 hours. The effluent NH4(+)-N values of less than 5 mg NH4(+)-N L-1 was consistently observed for the initial NH4(+)-N levels of as high as 1000 mg NH4(+)-N L-1. The nitrification rates for the first, second and third stages were found as 5.7, 46.8 and 102.8 mg NH4(+)-N L-1 h-1, respectively. The difference of the nitrification rates in the 2nd and 3rd stages originated from increasing adaption of the sludge as well as increasing biomass concentration (10.5 mg NH4(+)-N g-1 VSS h-1). No significant accumulation of NO2(-)-N has been observed during the study and NO2(-)-N/NOx(-)-N ratios measured in the 1st aerobic phase and the SBR effluent were less than 7%. The denitrification rates for the second (raw leachate as carbon source) and the third (Ca(CH3COO)2 as carbon source) stages were determined as 45.7 mg NOx(-)-N L-1 h-1 (or 9.85 mg NOx(-)-N g-1 VSS h-1) and 125.7 mg NOx(-)-N L-1 h-1 (or 12.88 mg NOx(-)-N g-1 VSS h-1), respectively.

Biological removal of ammonia and nitrate from simulated mine and mill effluents

Although nitrification/denitrification processes have been used to remove ammonia and nitrate from municipal and industrial processes, there are few reported results on the removal of these ions from mine effluents. Ammonia and nitrate are present in the effluent due to the widespread use of ammonium-nitrate-fuel oil (ANFO) as a blasting agent, and the use of other nitrogen-containing reagents in the mill. Unlike other process effluents, there is very little nutrient content in mine effluents. The objective of this work was to develop a microbial process for the removal of ammonia from simulated mine effluents. Biologically, this is accomplished in two steps. In the first step, ammonia is oxidized to nitrate, and in the second step, nitrate is reduced to dinitrogen gas. Ammonia oxidation (nitrification) was tested using both continuously stirred tank reactors and trickling filters. The stirred tank reactor was chosen for the combined system because it produced final effluents with lower ammonia concentrations. For nitrate reduction (denitrification), a packed bed reactor operated in the upflow mode was tested with methanol being used as a carbon and energy source. The nitrate profiles within the denitrification reactor showed an exponential decay, a characteristic of plug flow conditions. A simulation model was developed for the denitrification reactor which described performance as a function of feed nitrate (NO 3) and methanol concentrations (MeOH) and retention time (RT): Productivity (mg NO 3/l per hour)=0.722(NO 3)+(MeOH)[1.416−0.024 (MeOH)+0.0011(NO 3)−0.776(RT)]. The methanol to nitrate ratio required for denitrification was 0.86:1. When the two processes were set up in series, it was successful in removing ∼90% of the nitrogen.

Application of a granular activated carbon-biological fluidised bed for the treatment of landfill leachates containing high concentrations of ammonia

The Envirex granular activated carbon biological fluidized bed (GAC-BFB) process was used to treat landfill leachate containing organic material with typical COD values in the range 800 to 2,700 mg/l, but with high concentrations of ammonia in the range 220 to 800 mg/l. Prior to treatment the leachate was softened by raising the pH to 9.0 using lime in order to remove any contaminating heavy metals. Two identical pilot-plant GAC-BFB's were used in series to treat the softened leachate. The first of these was intended to achieve carbonaceous removal whilst the second was used for ammonia removal by nitrification. During the first four months of operation at a loading rate of 1.56 kg ammonia-N/m3 d, the reactors removed 70% of the ammonia, 60% of COD and achieved a complete removal of BOD. After optimising the reactor operating regime, it proved possible to achieve greater than 90% removal of ammonia at a loading rate of 0.71 kg N/m3 d; however the COD removal remained unchanged. In order to compare the ammonia removal efficiency of the GAC-BFB system, two conventional activated sludge reactors were operated in parallel at hydraulic retention times of 24 and 36 hours (equivalent to ammonia loadings of 0.72 and 0.48 kg ammonia-N/m3 d) and with a sludge age of 20 days. These reactors were not able to nitrify and although a BOD removal of 90% was achieved the COD removal was poor at 20%. Thus the GAC-BFB system offers a highly effective option for the biological removal of ammonia from high ammonia leachates, with the additional advantage of a good COD removal.

Application of a granular activated carbon?biological fluidised bed for the treatment of landfill leachates containing high concentrations of ammonia

The Envirex granular activated carbon biological fluidized bed (GAC-BFB) process was used to treat landfill leachate containing organic material with typical COD values in the range 800 to 2,700 mg/l, but with high concentrations of ammonia in the range 220 to 800 mg/l. Prior to treatment the leachate was softened by raising the pH to 9.0 using lime in order to remove any contaminating heavy metals. Two identical pilot-plant GAC-BFB9s were used in series to treat the softened leachate. The first of these was intended to achieve carbonaceous removal whilst the second was used for ammonia removal by nitrification. During the first four months of operation at a loading rate of 1.56 kg ammonia-N/m 3 d, the reactors removed 70% of the ammonia, 60% of COD and achieved a complete removal of BOD. After optimising the reactor operating regime, it proved possible to achieve greater than 90% removal of ammonia at a loading rate of 0.71 kg N/m 3 d; however the COD removal remained unchanged. In order to compare the ammonia removal efficiency of the GAC-BFB system, two conventional activated sludge reactors were operated in parallel at hydraulic retention times of 24 and 36 hours (equivalent to ammonia loadings of 0.72 and 0.48 kg ammonia-N/m 3 d) and with a sludge age of 20 days. These reactors were not able to nitrify and although a BOD removal of 90% was achieved the COD removal was poor at 20%. Thus the GAC-BFB system offers a highly effective option for the biological removal of ammonia from high ammonia leachates, with the additional advantage of a good COD removal.