denitrification reactor Articles
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Nitrogen removal from reject water with primary sludge as denitrification carbon source
A novel system was used for nitrogen removal from reject water. This system includes one anoxic/oxic reactor for nitrification and a special reactor for denitrification in which primary sludge was added intermittently as electron donor. In denitrification reactor, sludge fermentation and denitrification reaction took place simultaneously and promoted each other. It was found that effluent recycle ...
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Influence of denitrification reactor retention time distribution (RTD) on dissolved oxygen control and nitrogen removal efficiency
Low concentrations of dissolved oxygen (DO) are usually found in biological anoxic pre-denitrification reactors, causing a reduction in nitrogen removal efficiency. Therefore, the reduction of DO in such reactors is fundamental for achieving good nutrient removal. The article shows the results of an experimental study carried out to evaluate the effect of the anoxic reactor hydrodynamic model ...
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Evaluating the effects of nitrogen loading rate and substrate inhibitions on partial nitrification with FISH analysis
The effects of free ammonia (FA) or free nitrous acid (FNA) on partial nitrification (PN) has been well investigated. Nevertheless, little information was known about the combined effects of nitrogen loading rate (NLR) and substrate inhibition, as well as the impact on the community structure of nitrifiers. In this work, real reject water was treated in a pre-denitrification reactor. PN was ...
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A new reactor for denitrification and micro-particle removal in recirculated aquaculture systems
A ‘membrane-denitrification’ reactor (MDR) was developed and tested in a semi-technical recirculation aquaculture system in comparison to a double – without MDR – as reference system. The MDR consisted of a reactor with an ultrafiltration membrane unit for removal of micro-particles (e.g. sludge flocs, bacteria and parasites). Specific carrier material provided surfaces for biofilm growth in ...
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Hydrogenotrophic denitrification in an attached growth reactor under various operating conditions
To study the performance of an attached growth reactor on nitrate-nitrogen (NO3-N) removal by a hydrogenotrophic denitrification process, the reactor was operated under various H2 flow rates (30, 50 and 70 mL/min), hydraulic retention times (HRTs) (2.6, 3.1, 4.7 and 6.7 h) and inorganic carbon (IC) concentrations (excess and no IC addition). Synthetic NO3-N water was prepared in accordance with ...
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Optimizing external carbon source addition in domestics wastewater treatment based on online sensoring data and a numerical model
The removal of total nitrogen in wastewater treatment plants (WWTPs) is often unsatisfactory for a variety of reasons. One possible measure to improve nitrogen removal is the addition of external carbon. However, the amount of carbon addition is directly related to WWTP operation costs, highlighting the importance of accurately determining the amount of external carbon required. The objective ...
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Denitrification performance and microbial community dynamics in a denitrification reactor as revealed by high-throughput sequencing
The dynamics of the bacterial community associated with the denitrification process in a fixed bed column reactor (FBCR) were investigated using 454-pyrosequencing methodology. A FBCR filled with elemental sulfur and limestone was operated for about 94 days under autotrophic and mixotrophic (autotrophic + heterotrophic) conditions at 30 °C. Efficient simultaneous bromate and nitrate removal ...
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Nitrate removal from groundwater by hydrogen-fed autotrophic denitrification in a bio-ceramsite reactor
In this work, the denitrification performance of a bio-ceramsite reactor based on autohydrogenotrophic denitrification was investigated. The effects of various experimental parameters such as nitrate loading, carbon to nitrogen ratio (C/N), water temperature and pH were evaluated during the operation. The unique aspect of this research is that the bio-reactor uses ceramsite as a carrier, which ...
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Industrial flue gas desulfurization waste may offer an opportunity to facilitate SANI® application for significant sludge minimization in freshwater wastewater treatment
This paper reports an exploratory study on the use of a sulfite-rich industrial effluent to enable the integration of a sulfite–sulfide–sulfate cycle to the conventional carbon and nitrogen cycles in wastewater treatment to achieve sludge minimization through the non-sludge-producing Sulfate reduction, Autotrophic denitrification and Nitrification Integrated (SANI) ...
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Biological denitrification of brines from membrane treatment processes using an upflow sludge blanket (USB) reactor
This paper investigates denitrification of brines originating from membrane treatment of groundwater in an upflow sludge blanket (USB) reactor, a biofilm reactor without carrier. A simulated brine wastewater was prepared from tap water and contained a nitrate concentration of 125 mg/l as N and a total salt concentration of about 1%. In order to select for a suitable energy source for ...
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Nitrogen removal from high organic loading wastewater in modified Ludzack–Ettinger configuration MBBR system
A moving bed biofilm reactor with pre-denitrification configuration was fed with a synthetic wastewater containing high chemical oxygen demand (COD) and ammonia. By changing different variables including ammonium and COD loading, nitrification rate in the aerobic reactor and denitrification rate in the anoxic reactor were monitored. Changing the influent loading was achieved via adjusting the ...
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Mixed electron donor autotrophic denitrification processes for groundwater treatment by immobilized biological filters
An immobilized biological filter (IBF) using Fe(II) and Mn(II) as mixed electron donors was evaluated for nitrate removal in groundwater. Results of the single factor experiments of strain SZ28 under the conditions of electron donor:electron acceptor ratio (1:2, 1.45:1, 3:1), Fe(II):Mn(II) ratio (1:9, 3:7, 5:5) demonstrated that the highest nitrate removal ratio was 100%, 49.6% (Mn(II)) and ...
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Enhancement of denitrification in a down-flow hanging sponge reactor by effluent recirculation
A down-flow hanging sponge reactor, constructed by connecting three identical units in series, was applied to the treatment of artificial wastewater containing phenol and ammonia under high salinity conditions (10.9 g-Cl−/L). The theoretical hydraulic retention time (HRT) of each unit was 4 h (total HRT = 12 h). To enhance denitrification by effluent recirculation, the effluent ...
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Rapid cultivation of aerobic granular sludge for Simultaneous Nitrification and Denitrification in Sequencing Batch Airlift Reactor
The cultivation of aerobic granular sludge in Sequencing Batch Airlift Reactor (SBAR) was investigated. The results showed that the aerobic granular sludge could be formed in short time (35 d) owing to better shear force and selective pressure in SBAR. Meanwhile, aerobic granulation was clearly accelerated when the external carbon source was intermittently added at one-cycle intervals. The mean ...
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Performance of upflow anoxic bioreactor for wastewater treatment
Laboratory scale studies were conducted in an up-flow anoxic bioreactor (UFAB) using synthetic fertilizer wastewater for ascertaining the denitrification efficiency. The performance of the reactor was compared using ethanol and topioca starch as the carbon source. The initial NO3-N concentrations (50-250 mg/L) and hydraulic retention time (HRT, 12-24 h) were varied to evaluate the COD and NO3-N ...
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Nutrient Optimization for Pulp & Paper Wastewater Treatment Plants - An Opportunity for Major Cost Savings
Abstract Pulp & paper wastewater treatment plants (WWTP) often add nitrogen and phosphorus to ensure optimum performance. If there are insufficient nutrients for bacterial metabolism, an increase in effluent total suspended solids (TSS), biological oxygen demand (BOD) and/or chemical oxygen demand (COD) may occur. As well, nutrient deficiency can cause or contribute to acute or chronic ...
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Improving total nitrogen removal in aeration basin retrofitted with entrapped biomass
This study presented a method to upgrade existing aeration tanks to remove total nitrogen (TN). Bioplates carrying entrapped biomass were installed in an aeration basin to create anoxic/anaerobic zones where denitrification can proceed. In a reactor that coupled bioplates containing entrapped biomass (equivalent to as high as 7,500 mg/L of biomass) and an activated sludge suspension (at mixed ...
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Impact of carbon to nitrogen ratio on nitrogen removal at a low oxygen concentration in a sequencing batch biofilm reactor
A sequencing batch biofilm reactor (SBBR) filled with polyurethane (PU) was operated in low dissolved oxygen (DO) (0.1–0.9 mg/L) at three different carbon to nitrogen ratios (C/N ratios) (C/N = 1.8:1, 5.0:1 and 10.5:1) with focus on reactor performance and microbial community composition of nitrifying and denitrifying bacteria. Meanwhile, the ammonium, nitrite, nitrate, pH and ...
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Characterization and kinetics of sulfide-oxidizing autotrophic denitrification in batch reactors containing suspended and immobilized cells
Sulfide-oxidizing autotrophic denitrification is an advantageous alternative over heterotrophic denitrification, and may have potential for nitrogen removal of low-strength wastewaters, such as anaerobically pre-treated domestic sewage. This study evaluated the fundamentals and kinetics of this process in batch reactors containing suspended and immobilized cells. Batch tests were performed for ...
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Nitrification/denitrification in swine wastewater using porous ceramic sticks with plastic rings as supporting media in two-stage fixed-biofilm reactors
This study evaluated the performance of oxic-anoxic fixed-biofilm reactors (FBRs) using porous ceramic sticks with plastic rings as supporting media for nitrogen and organic carbon (as COD) removal from swine wastewater. Experimental results indicate that the removal efficiency of NH4+-N increased to 86–92% from 52–98% as the volumetric ammonium-nitrogen loading rate increased to 0.25 kg ...
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