Denitrification Filter Research Articles

Nitrate Removal from Domestic Wastewater by Using Denitrification Limestone Filter

Nitrogen is a naturally occurring element that is essential for growth and reproduction in both plants and animals. Excessive concentrations in the water body can cause excessive growth of algae and other plants, leading to accelerate eutrophication of lakes, and occasional depletion of dissolved oxygen. To remove nitrogen conventionally from domestic wastewater requires a high cost technology due to consumption of chemicals, high operational and maintenance cost. Therefore, an alternative low cost treatment technology particularly for nutrient removal including nitrogen removal system has been developed to improve the final effluent quality that is an aerated rock filter system. However, in the previous works in the UK the system was outperformed in removing ammonia nitrogen with limited nitrate removal. Hence, the present study was carried out to investigate the removal of nitrate from domestic wastewater through denitrification process using a lab-scale limestone filter. Domestic wastewater sample used in this study was collected from Taman Bukit Perdana Wastewater Treatment Plant (WWTP), Batu Pahat, Johor owned by IWK. The treatments were run in lab-scale limestone denitrification filter for 10 weeks. Effluent from nitrification filter was passing through the limestone denitrification filter as influent for further treatment. The in fluent and effluent of the filter system have been sampled and analyzed on biweekly basis for selected parameters including pH, alkalinity, temperature, dissolved oxygen, nitrate and ammonia nitrogen to monitor the effectiveness of the filter. Results from this study show that denitrification process has took place even the percentages of nitrate removal were considerably low but it seems promising with some modification of designing the the limestone filter to enhance denitrification process. The highest removal rate was 17.66%. Low removal of nitrate was inhibited within the filter system might be due to the high DO concentration as it was found that the range of DO was 4.75-7.78 mg/L. To permit the denitrification process to take place within the filter system, it is required an anoxic condition in the presence of nitrate with minimum DO concentration. Consequently, some modifications to the filter design will be considered in the future research in order to enhance the removal of nitrate through denitrification process.

Taking Denitrification to the Next Level: An Upgrade of Proven Technology With 21st Century I&C

In 2006, one of the largest wastewater reclamation facilities in the northern Virginia area recognized the need to expand the facility from 18 to 24 mgd (million gallons per day). In part, the upgrade was triggered by regulations requiring reduction of Total Nitrogen discharge on an annual basis to 3 mg/L. At the same time, there was a need to replace their plant-wide data acquisition and control system (DACS), with a new modern supervisory control and data acquisition (SCADA) system. This design-build project also provided “limit of technology” nutrient removal; the existing aeration basin volume was doubled and reconfigured to allow operation in either 4-stage Bardenpho or modified ludzack ettinger (MLE) modes; 14 new de-nitrification filters were implemented for a total of 24; and a second/standby chemical analyzer was installed for redundancy purposes. Furthermore, methanol feed was automated to be flow paced and controlled by a proprietary software calculation algorithm. The proprietary software calculation algorithm for control is feed-forward/feed-back based upon flow and influent and effluent nitrate concentrations. This enhanced the operation and reliability of the process and also reduced the risk of methanol overdose by more closely matching the methanol to feed demand. Consistent methanol dose control is challenging when trying to meet low effluent total nitrogen while simultaneously maintaining a low Carbonaceous Biochemical Oxygen Demand (CBOD). This plant is currently in full operation, being controlled by plant staff, and in compliance with the regulation requirements that triggered the plant-wide upgrade in the first place. This paper will discuss the integration of new technologies, the operational benefits, and the startup coordination required to reliably meet the new operating permit limits.

Lessons Learned from Performance Testing of Seven Denitrification Filters under Varying Conditions

Lessons Learned from Performance Testing of Seven Denitrification Filters under Varying Conditions

Full-scale operating experience of deep bed denitrification filter achieving <3 mg/l total nitrogen and <0.18 mg/l total phosphorus

The Arlington County Wastewater Pollution Control Plant (ACWPCP) is located in the southern part of Arlington County, Virginia, USA and discharges to the Potomac River via the Four Mile Run. The ACWPCP was originally constructed in 1937. In 2001, Arlington County, Virginia (USA) committed to expanding their 113,500 m³/d, (300,000 pe) secondary treatment plant to a 151,400 m³/d (400,000 pe) to achieve effluent total nitrogen (TN) to <3 mg/l and total phosphorus (TP) < 0.18 mg/l. Key to this conversion was the implementation of deep bed denitrification filters to simultaneously achieve both low effluent TN and TP concentrations. A challenge with implementing this technology is maintaining a health denitrifying biomass within the denitrification filters while reducing an essential nutrient, phosphorus, to very low concentrations. This paper will review the steps from concept to the first year of operation, including pilot and full-scale operating data and the capital cost for the denitrification filters.

Herbicide and Antibiotic Removal by Woodchip Denitrification Filters: Sorption Processes

In situ denitrification walls and biofilters made of wood chips are being implemented as innovative technologies for the removal of nitrates in tile drainage water from farms to reduce pollution of surface waters and the hypoxia problem in the Gulf of Mexico. Although fairly effective in removing nitrates, not much is known about the effectiveness of the biofilters in removal of herbicides, pesticides, and antibiotics in the drainage water. Using weathered wood chips obtained from an in situ denitrification wall, four common pollutants tested sorbed strongly to wood chips in the following order: enrofloxacin > monensin A > atrazine > sulfamethazine. Of the four chemicals tested, enrofloxacin was found to desorb the least by water extraction. The apparent hysteresis index for atrazine was found to be lower than that for enrofloxacin and sulfamethazine indicating greater sorption–desorption hysteresis for atrazine than enrofloxacin and sulfamethazine. Consecutive steps of water desorption and organic solvent extraction indicated that more than 65% of the sorbed atrazine, 70% of sulfamethazine, 90% of enrofloxacin, and 80% of monensin A were retained in wood chips. Results of this study showed that wood chip denitrification walls or biofilters have an added benefit in retaining herbicides and antibiotics and therefore can act as a barrier to reduce pollution of surface water and groundwater.

Observations on the Performance and Modeling of Glycerin- and Methanol-fed Denitrification Filters

Observations on the Performance and Modeling of Glycerin- and Methanol-fed Denitrification FiltersThe objective of this investigation was to utilize the full-scale denitrification filter data from five treatment plants to explore the significance of the following variables on nitrate removal rate: (a) nitrate loading rate (NLR), (b) hydraulic loading rate (HLR), (c) temperature, and (d) PO4- P:NO3-N ratio. Much of this data was gathered in prior studies (Bilyk et al. 2008 and 2011; Ledwell et...Author(s)Katya BilykPeter DoldSamuel LedwellRon LatimerPaul PittMary SadlerSourceProceedings of the Water Environment FederationSubjectSession 32: Supplemental Carbon for DenitrificationDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2011ISSN1938-6478SICI1938-6478(20110101)2011:15L.1598;1-DOI10.2175/193864711802713405Volume / Issue2011 / 15Content sourceWEFTECFirst / last page(s)1598 - 1614Copyright2011Word count112Subject keywordsDenitrificationfiltercarbonmethanolglyceringlycerolmodelingphosphorus limitation

Observations on the Performance and Modeling of Glycerin-fed Denitrification Filters

Observations on the Performance and Modeling of Glycerin-fed Denitrification Filters

Can We Operate Deep Bed Denitrification Filters With Limited Phosphorus?

Can We Operate Deep Bed Denitrification Filters With Limited Phosphorus?

Application of rbcL based molecular diversity analysis to algae in wastewater treatment plants

The molecular diversity of algae in the final clarifier or denitrification filter outfall from three wastewater treatment plants (WWTPs) with activated sludge based treatment was analyzed using the rbcL gene as a phylogenetic marker. The rbcL gene encodes the large subunit of the CO(2) fixing enzyme RuBisCO. Among algae identified at the WWTPs were diatoms, green algae, cyanobacteria, Eustigmatophyceae, and unknown heterokonts. A high level of diversity was observed within WWTPs with 19-24 unique rbcL sequences detected at each plant. Algae composition also varied between treatment plants. Our results show that the rbcL gene can be used as a phylogenetic marker for algae diversity analysis in a wastewater treatment context.

Experiences in Using MBBR and Denitrification Filters for Nitrogen Removal from Saline Wastewater

Experiences in Using MBBR and Denitrification Filters for Nitrogen Removal from Saline WastewaterAs water recycling becomes more widespread, brine disposal and the removal of nitrogen and phosphorus from a wastewater that is relatively high in chlorides have emerged as important areas of study and development. This paper discusses the use of biofilm processes for both nitrification and denitrification of saline wastewaters. Testing results from parallel pilot-scale submerged aerated filter...Author(s)C. deBarbadilloJ. BatesT. ChanM. SteichenC. Wallis-LageSourceProceedings of the Water Environment FederationSubjectSession 3: MBBR IFASDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2010ISSN1938-6478SICI1938-6478(20100101)2010:7L.254;1-DOI10.2175/193864710798208719Volume / Issue2010 / 7Content sourceResiduals and Biosolids ConferenceFirst / last page(s)254 - 264Copyright2010Word count139Subject keywordsSaline wastewaternitrifying MBBRdenitrification filters

Can We Operate Deep Bed Denitrification Filters with Limited Phosphorus?

Can We Operate Deep Bed Denitrification Filters with Limited Phosphorus?

Cold Weather Design and Operational Considerations for Deep-bed Denitrification Filters to Achieve Limit-of-Technology Nutrient Removal

Cold Weather Design and Operational Considerations for Deep-bed Denitrification Filters to Achieve Limit-of-Technology Nutrient Removal

Considerations for Alternative Supplemental Carbon Sources in Deep Bed Denitrification Filters to Achieve Low Effluent Nutrient Concentrations

Considerations for Alternative Supplemental Carbon Sources in Deep Bed Denitrification Filters to Achieve Low Effluent Nutrient Concentrations

Biological nutrient and organic removal from meat packing wastewater with a unique sequence of suspended growth and fixed-film reactors

A unique sequence of anaerobic filter/suspended anaerobic/aerobic (AO) reactor/aerobic filter system was developed to alleviate the drawbacks of conventional suspended growth and fixed growth systems. An anaerobic filter (AF) was used to efficiently produce volatile fatty acids (VFAs) prior to the aerobic suspended growth. A second anaerobic reactor was installed in the A/O return activated sludge line to improve phosphorus uptake by potentially controlling glycogen accumulating organisms (GAOs). One biological aerobic filter (BAF) was used for nitrification followed by an anoxic filter for denitrification and a second BAF was used for effluent polishing. The meat packing wastewater had a biochemical oxygen demand (BOD) of 853 mg/L and total nitrogen (T-N) and total phosphorus (T-P) concentrations of 61.1 mg/L and 5.8 mg/L, respectively. The BOD removal efficiency was 99.0-99.7% and the suspended solids (SS) concentration in the effluent was below 10 mg/L. The T-N removal efficiency was maintained at greater than 75.0% except at low C/N ratios. A high T-P removal efficiency, 74.7-83.9%, was also obtained when the system was operated at a hydraulic retention time of 15.7 hrs. The AF successfully produced VFAs that aided in phosphorus removal. Additionally, recycled concrete aggregate used as attachment media in the biological filters continuously provided micronutrients and stabilized the pH.

Application and comparison of dynamic models to assess impact of loading variations on performance of denitrification filters

Dynamic models were developed using two software packages to evaluate performance of a denitrification filter pilot under variable flow and nitrate loading conditions. Two data periods, including one at constant rate hydraulic loading and one under diurnal flow conditions, were used to calibrate the models. Two additional test periods, one with high nitrate loadings and the second with peak hydraulic loadings and intermittent methanol usage were used to validate the models. The paper presents the results and compares the features of the two models.

Steady-state model-based evaluation of sulfate reduction, autotrophic denitrification and nitrification integrated (SANI) process

Recently we developed a process for wastewater treatment in places where part of the fresh water usage is replaced by seawater usage. The treatment of this saline sewage consists of sulfate reduction, autotrophic denitrification and nitrification integrated (SANI) process. The process consists of an up-flow anaerobic sludge bed (UASB) for sulfate reduction, an anoxic filter for autotrophic denitrification using dissolved sulfide produced in the UASB and an aerobic filter for nitrification. The system was operated for 500 days with 97% COD removal and 74% total nitrogen removal without withdrawal of sludge. To verify these results and to understand this novel process, a steady-state model was developed from the COD, nitrogen and sulfur mass and charge balances based on the stoichiometries of the sulfate reduction, the autotrophic denitrification and the autotrophic nitrification. The model predictions agreed well with measured data on COD, nitrate and sulfate removal, sulfide production, effluent TSS, and mass balances of COD, sulfur and nitrogen in the three reactors. The model explains why withdrawal of sludge from the SANI system is not needed through comparisons of the predictions and measurements of effluent TSS and phosphorus concentrations.

A novel sludge minimized biological nitrogen removal process for saline sewage treatment

This study reports a lab-scale evaluation of a new biological nitrogen removal process for saline sewage treatment, namely a SANI process (Sulfate reduction, Autotrophic denitrification and Nitrification Integrated process). The experimental system consisted of an up-flow anaerobic bed for sulfate reduction, an anoxic filter for autotrophic denitrification using dissolved sulfide produced in the up-flow anaerobic bed and an aerobic filter for nitrification. The system successfully operated for more than 180 days with an overall organic carbon removal efficiency of 95%, in which, 82% removal was contributed by the up-flow anaerobic bed operating at a HRT of 6 h, and 13% removal by the anoxic filter. An average COD removed /sulfate removed ratio was found to be 0.76 gCOD/gSO(4) or 2.28 COD/gSO(4)-S further confirming that the organic removal was mainly achieved by the sulfate reduction. In terms of nitrogen removal efficiency, the SANI system was found sensitive to the recirculation rate between the anoxic filter and the aerobic filter. A recirculation rate of 3Q was found to be optimal for achieving 74% of the total nitrogen removal. It was confirmed that the autotrophic denitrification was a major contributor to the total nitrogen removal in the SANI system. Sulfur balance analysis indicated that both the accumulation of elementary sulfur in the biomass and the loss of hydrogen sulfide were trivial. During the entire operation period (330 days to date), no sludge was wasted from any reactors in this system. This was further confirmed by the biomass balance simulation results that low biomass yields of sulfate reducing bacteria, autotrophic denitrifiers and nitrifiers contribute to the zero excess sludge discharge.

Removal of nitrate and phosphorus from hydroponic wastewater using a hybrid denitrification filter (HDF)

A laboratory-scale hybrid-denitrification filter (HDF) was designed by combining a plant material digester and a denitrification filter into a single unit for the removal of nitrate and phosphorus from glasshouse hydroponic wastewater. The carbon to nitrate (C:N) ratio for efficient operation of the HDF was calculated to be 1.93:1 and the COD/BOD 5 ratio was 1.2:1. When the HDF was continuously operated with the plant material replaced every 2 days and 100% internal recirculation of the effluent, a high level of nitrate removal (320–5 mg N/L, >95% removal) combined with a low effluent sBOD 5 concentration (<5 mg/L) was consistently achieved. Moreover, phosphate concentrations in the effluent were maintained below 7.5 mg P/L (>81% reduction). This study demonstrates the potential to combine a digester and a denitrification filter in a single unit to efficiently remove nitrate and phosphate from hydroponic wastewater in a single unit.

A novel sulfate reduction, autotrophic denitrification, nitrification integrated (SANI) process for saline wastewater treatment

This paper reports on a lab-scale evaluation of a novel and integrated biological nitrogen removal process: the sulfate reduction, autotrophic denitrification and nitrification integrated (SANI) process that was recently proposed for saline sewage treatment. The process consisted of an up-flow anaerobic sludge bed (UASB) for sulfate reduction, an anoxic filter for autotrophic denitrification and an aerobic filter for nitrification. The experiments were conducted to evaluate the performance of the lab-scale SANI system with synthetic saline wastewater at various hydraulic retention times, nitrate concentrations, dissolved oxygen levels and recirculation ratios for over 500 days. The system successfully demonstrated 95% chemical oxygen demand (COD) and 74% nitrogen removal efficiency without excess sludge withdrawal throughout the 500 days of operation. The organic removal efficiency was dependent on the hydraulic retention time, up-flow velocity, and mixing conditions in the UASB. Maintaining a sufficient mixing condition in the UASB is important for achieving effective sulfate reduction. For a typical Hong Kong wastewater composition 80% of COD can be removed through sulfate reduction. A minimum sulfide sulfur to nitrate nitrogen ratio of 1.6 in the influent of the anoxic filter is necessary for achieving over 90% nitrate removal through autotrophic denitrifiers which forms the major contribution to the total nitrogen removal in the SANI system. Sulfur balance analyses confirmed that accumulation of elementary sulfur and loss of hydrogen sulfide in the system were negligible.

Full-Scale Denitrification Evaluations using Sugar Water, Glycerin, and Methanol in Denitrification Filters and Activated Sludge

Full-Scale Denitrification Evaluations using Sugar Water, Glycerin, and Methanol in Denitrification Filters and Activated Sludge