Slaughterhouse wastewater (SWW) possesses very high organic and nutrient concentrations and its residues are moderately solubilized, which leads to pollution affecting the environment and human health. The objective of this study was to investigate the effective removal of ammonium in slaughter wastewater by up flow anaerobic sludge blanket (UASB) technology combined with an expanded granular sludge bed (EGSB) using anammox and PVA gel as the biomass carrier. Ammonium loading rates (NLRs) increased from 0.25 kg N-NH4 + /m3 .d to 0.75 kg N-NH4 + /m3 .d with hydraulic retention times (HRTs) of 12, 6, and 4 h.
Environmental Sciences | Ecology Doi: 10.31276/VJSTE.62(1).85-89 Treatment of ammonium in slaughterhouse wastewater by UASB technology combined with EGSB using anammox and PVA gel Minh Nhat Phan1, Nguyen Van Nhi Tran2, Jimmy Yu2, Tan Phong Nguyen1* Faculty of Environment and Natural Resources, University of Technology, Vietnam National University, Ho Chi Minh city Civil and Environmental Engineering, School of Engineering and Built Environment, Griffith University, Australia Received 22 January 2020; accepted 10 March 2020 Abstract: Introduction Slaughterhouse wastewater (SWW) possesses very high organic and nutrient concentrations and its residues are moderately solubilized, which leads to pollution affecting the environment and human health The objective of this study was to investigate the effective removal of ammonium in slaughter wastewater by up flow anaerobic sludge blanket (UASB) technology combined with an expanded granular sludge bed (EGSB) using anammox and PVA gel as the biomass carrier Ammonium loading rates (NLRs) increased from 0.25 kg N-NH4+/m3.d to 0.75 kg N-NH4+/m3.d with hydraulic retention times (HRTs) of 12, 6, and 4 h The system was operated in phases In phase 1, the removal of ammonium by employing the combination of UASB technology and EGSB using anammox was examined The removal efficiencies of nitrite were 52% (NLRs=0.25 kg N-NH4+/m3.d), 69% (NLRs=0.5 kg N-NH4+/m3.d) and 64% (NLRs=0.75 kg N-NH4+/m3.d) On the other hand, the removal efficiencies of ammonium were about 37% (NLRs=0.25 kg N-NH4+/m3.d), 64% (NLRs=0.5 kg N-NH4+/m3.d) and 55% (NLRs=0.75 kg N-NH4+/m3.d) In phase 2, a PVA gel was supplied to the EGSB as the biomass carrier for growing the anammox sludge The result showed that the removal efficiencies of nitrite were about 55% (NLRs=0.25 kg N-NH4+/m3.d), 77% (NLRs=0.5 kg N-NH4+/m3.d), and 73% (NLRs=0.75 kg N-NH4+/m3.d) In addition, the removal efficiencies of ammonium were about 56% (NLRs=0.25 kg N-NH4+/m3.d), 68% (NLRs=0.5 kg N-NH4+/m3.d), and 60% (NLRs=0.75 kg N-NH4+/m3.d) The main pollutant sources of wastewater from the slaughtering process are paunch, faeces, fat and lard, grease, undigested food, blood, suspended material, urine, loose meat, soluble proteins, excrement, manure, grit, and colloidal particles SWW contains large amounts of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), and total suspended solids (TSS) The treatment of SWW has been achieved by traditional methods such as aerobic and anaerobic biological systems Keywords: ammonium removal, anammox, EGSB, PVA gel Classification number: 5.1 *Corresponding author: Email: ntphong@hcmut.edu.vn Anammox (anaerobic ammonium oxidation) is a globally important microbial of the cycle suspended solids (TSS) Theprocess treatment of nitrogen SWW has been achieved b that takes place in many natural processes Anammox is methods such as aerobic and anaerobic biological systems a reaction that ammonium oxidation to dinitrogen gas using Anammox (anaerobic ammonium oxidation) is a [1] globally importa nitrite as the electron acceptor under anoxic conditions process of the nitrogen cycle that takes place in many natural Since its discovery two decades of ago, anammox-related processes A reaction oxidationhave to dinitrogen gas using nitrite as the elec research that andammonium its applications experienced strong under anoxic conditions [1] Since its discovery two decades growth Researchers have considered the anammox process of ago, ana research and of its treating applications have experienced strong growth Rese as a method the high-nutrient concentrations considered the anammox process as a method of treating the high-nutrient c of wastewater Based on mass balance from culture of wastewater Based on mass batch balance from(SBR) culturetoexperiments using experiments using a sequencing reactor take batch reactor to take account of the biomass growth, account of the(SBR) biomass growth, the anammox reaction has the anammox the following following scaling scalingcoefficients coefficients[2, [2,3] 3] (1) (1) In comparison comparison with traditional In traditional technologies, technologies,anammox anammoxhas many advan high nitrogen removal, such low as operational costs, removal, and small space requ has many advantages high nitrogen Anammox has been successfully treatment of[4] wastewater on t low operational costs, and smallapplied space to requirement scale, pilot has scale, andsuccessfully full scale Many types of wastewater Anammox been applied to treatment of have been s positive results anammox has been wastewater on For the example, laboratorythescale, pilot process scale, and full applied to the scale Many types of wastewater have been surveyed with landfill leachate This research showed that ammonium removal effici positiveand results example, the anammox process been 88.1% TNFor removal efficiency reached 80%has [2] However, in th applied to process the treatment of landfill leachate with This PVA research anammox is applied in combination gel for the treatm The purpose of the study is to assess slaughter wastewater treated by combined with EGSB technologies as well as to evaluate the factors th treatment efficiency of these processes Material and methods Feed SWW March 2020 • Vol.62 Number Vietnam Journal of Science, Technology and Engineering 85 SWW was taken from the VISSAN Company's wastewater treatme characteristic of the SWW is shown in Table batch batch reactor reactor (SBR) (SBR) to to take take account account of of the the biomass biomass growth, the the anammox reaction reaction has batch reactor (SBR) to take account of the biomass growth, growth, the anammox anammox reaction has has the following scaling coefficients [2, 3] the following scaling coefficients [2, 3] the following scaling coefficients [2, 3] (1) (1) (1) In comparison with technologies, anammox has many advantages such as In traditional In comparison comparison with with traditional traditional technologies, technologies, anammox anammox has has many many advantages advantages such such as as high nitrogen removal, low operational costs, and small space requirement [4] high nitrogen nitrogen removal, removal, low low operational operational costs, costs, and and small small space space requirement requirement [4] [4] high Anammox has been successfully applied to treatment of wastewater on the laboratory Anammox been applied treatment on showed thathas ammonium removal efficiency reached 88.1%of The wastewater pumped to the UASB was stored in a Anammox has been successfully successfully applied to to treatment of wastewater wastewater on the the laboratory laboratory scale, pilot scale, and full scale Many types of wastewater have been surveyed scale, pilot scale,efficiency and full full reached scale Many Many types of wastewater wastewater have been surveyed with and TN removal 80% [2] However, in tank withbeen volume of 90 l with The UASB is an acrylic tube with scale, pilot scale, and scale types of have surveyed with positive results For example, the anammox process has been applied to the treatment of this study, the anammox process is applied in combination a working volume of 10 l positive results For example, the anammox process has been applied to the treatment of positive results For example, the anammox process has been applied to the treatmentwith of a height of 1.2 and 0.09 m landfill leachate This research showed that ammonium removal efficiency reached with PVA gel for the treatment of SWW The purpose of internal diameter On the column, there are inspection landfill leachate leachate This This research research showed showed that that ammonium ammonium removal removal efficiency efficiency reached reached landfill the study is to assess slaughter wastewater treated by using valves Each of these are 30 cm apart to collect wastewater 88.1% and TN removal efficiency reached 80% [2] However, in this study, the 88.1% 88.1% and and TN TN removal removal efficiency efficiency reached reached 80% 80% [2] [2] However, However, in in this this study, study, the the UASB combined with EGSB technologies as well as to sludge samples PN also an acrylic tube The anammox for treatment of SWW anammox process process is is applied applied in in combination combination with with PVA PVA gel gel and for the the treatment of The SWW anammox process is applied in combination with PVA gel for the treatment of SWW evaluate the factors that affect the treatment efficiency of working volume is 12.4 l with 0.78 m height and 0.14 m The purpose of of the study is to assess slaughter wastewater treated by using UASB The purpose treated by using UASB The of the the study study is is to to assess assess slaughter slaughter wastewater wastewater treated bycentral usingpipe UASB thesepurpose processes diameter The is made of PVC and is composed combined combined with with EGSB EGSB technologies technologies as as well well as as to to evaluate evaluate the the factors factors that that affect affect the the combined with EGSB technologies as well as to evaluate that affect ofthe a 40factors cm long section of the pipe connected to a cone with a treatment efficiency of these processes Material efficiency and methods treatment of treatment efficiency of these these processes processes chisel around it Air flow was supplied from the bottom of Material and methods the tank through an air pump and adjusted through a valve Feed SWW Material and Material and methods methods After passing the UASB-PN, wastewater will be stored SWWSWW was taken from the VISSAN Company’s Feed Feed Feed SWW SWW in tanks with volume of 90 l and pumped into the EGSB wastewater treatment plant The characteristic of the SWW SWW was taken from the VISSAN Company's wastewater treatment plant The tank The EGSB tank an acrylic tube with a working SWW was taken from the VISSAN Company's wastewater treatment plant SWWinwas treatment plant.is The The is shown Tabletaken from the VISSAN Company's wastewater volume of 10 l, 1.2 m high and 0.09 m internal diameter characteristic of the SWW is shown in Table characteristic of is characteristic of the the SWW SWW is shown shown in in Table Table 1 Table Characteristics of SWW Water circulation in the tank is done through a circulating Table of SWW Table Characteristics Characteristics of SWW Table of Unit SWW pump The treatment efficiency of the system is analysed Parameter Value Serial Characteristics Serial Parameter Unit Value Serial Parameter Unit Value and evaluated Serial Parameter Unit Value pH 6.6-7.9 Environmental Sciences | Ecology 1 2 23 3 44 4 5 5 pH pH pH COD COD COD COD -N -N -N TKN TKN TKN TKN N _N N _N N N Alkalinity Alkalinity Alkalinity Alkalinity TP TP TP 6 66 7 77 8 9 9 TP Temperature Temperature Temperature Temperature mg/l mg/l mg/l mg/lmg/l mg/l mg/l mg/l mg/lmg/l mg/l mg/l mg/lmg/l mg/l mg/l mg/l mg/lmg/l mg/l mg CaCO3/l 6.6-7.9 6.6-7.9 1,000-1,400 1,000-1,400 1,000-1,400 90-140 90-140 90-140 90-140 130-170 130-170 130-170 130-170 0-1.58 0-1.58 0-1.58 0-1.58 6.6-7.9 1,000-1,400 0-2.50 0-2.50 0-2.50 0-2.50 600-1,200 mg CaCO /l CaCO /l 33/l mg mg CaCO 600-1,200 600-1,200 600-1,200 mg/lo 15-35 C 28-31 mg/l mg/l mg/l o oC oC C 15-35 15-35 15-35 28-31 28-31 28-31 Set-up Set-up of of experiment experiment and and operational operational conditions conditions Set-up of experiment and operational conditions Set-up of experiment and operational conditions The lab-scale system has three reaction tanks including the UASB, partial nitrification (PN), and EGSB is shown in Fig Enrichment of sludge and PVA gel Enrichment of sludge: anaerobic sludge is taken from the anaerobic tankand ammonia-oxidizing bacteria (AOB) sludge is taken from the aeration tank of the VISSAN wastewater treatment system The anammox sludge is taken from the Institute of Tropical Biology, Ho Chi Minh city PVA gel: the PVA gel was provided by KURARAY AQUA CO., LTD The PVA (Polyvinyl alcohol) gel is comprised of mm spherical beads having a specific gravity of 1.025 One PVA-gel bead can hold up to billion microorganisms depending on operating conditions [5] 2 Operational conditions (Table 2) Table Operational conditions Input flow (l/h) HRT (h) Ammonium loading rate (kg NH4+-N/m3.d) DO PN (mg/l) Operating time (d) 0.5 12 0.25 0.8-1.0 1-20 0.5 0.8-1.0 21-40 1.5 0.75 1-1.2 41-60 Wastewater was brought from the wastewater tank to the UASB through a pumping system The reactor was operated in dark conditions by using a black plastic sheet fully covering the body to prevent the growth of algae The mixed liquor suspended solids (MLSS) concentration of the reactor was maintained within 15,000 mg/l The purpose of the UASB is to treat large quantities of organic matter in wastewater by converting organic nitrogen into ammonia to facilitate subsequent processing Fig Schematic diagram of the lab-scale system (1) Influent tank, (2) Influent pump, (3) Air pump, (4) Air valve, (5) Pump, (6) Circulating pump, (7) pH probe, (8) Biogas collection 86 Vietnam Journal of Science, Technology and Engineering Water self-flowed from the UASB to the PN tank The MLSS in the PN was kept in the range of 4,000-5,000 mg/l, the DO was adjusted from 0.8 to 1.2 mg O2/l, and the pH March 2020 • Vol.62 Number Environmental Sciences | Ecology The EGSB tank contains the activity of anammox microorganisms in anaerobic conditions In addition, there is a water circulation pump that create a disturbance in the tank to increase the contact between the wastewater and microorganisms The biological processes that take place in the tank will reduce the nitrogen content in the wastewater The model is split into two stages During stage one, the UASB/EGSB-anammox alone treated the SWW In stage 2, the PVA gel was introduced into the model as a biomass carrier + alkalinity parameters in the operation were adjusted to quickly improve the ratio In the After the first 10 days the loading rate of ammonium + proceeding days, the ratio of +NO2 N/NH -N increased gradually day by day Until the + thcorresponding to- HRT of -N/m d, was up to 0.75 kg NH ratio reached its highest value on the 27 day, with an of NO2 -N/NH4 -N of 1.4 and th h, and theefficiency resultsofshowed thatOnthe conversion efficiency of 4+-N was day, the ratio of NO2 N/NH conversion nearly 57% the 30 + 1.31, which is similar to the theoretical and theof ammonium conversion ammonium decreased to 44%, ratio, the ratio NO2 -N/NH -Nefficiency + the range of 1.22±0.2 is reached 60%.in In general, an average NO2 N/NHand -N ratio fluctuated the range of 0.9-0.93, the inlowest ratio, suitable for the anammox process inth the EGSB tank 0.79, was found on the 44 day This proves that changing firsta10great days the loadingon ratethe of ammonium was Increased up to 0.75 kg NH4+the After loadthehas impact processes N/m3.d, corresponding to HRT of h, and the results showed that the conversion load makes AOB sludge not able to adapt to the new living efficiency of ammonium decreased to 44%, the ratio of NO2 N/NH4+-N fluctuated in the environment other processes become This proves that range of 0.9-0.93,and and the lowestbiological ratio, 0.79, was found on thealso 44th day unstable process gradually in theload following changing theThe load has a great impact on the stabilized processes Increased makes AOB sludge + not ableThen to adapt the new living and other biological processes also days 10 todays later, theenvironment ratio of NO -N/NH -N was The process gradually stabilized in the following days Then 10 days become unstable 1.1±0.04 and relatively stable On day 59, the ammonium later, the ratio of NO2 N/NH4+-N was 1.1±0.04 and relatively stable On day 59, the conversion efficiency reached 59% ammonium conversion efficiency reached 59% After the loading rate of ammonium was increased to 0.5 kg NH4+-N/m3.d, the input wastewater had a relatively stable ammonium content (123±8.8 mg/l) The ammonium concentration after passing through UASB tank increased to 130±8 mg/l During the first few days during the loading process, the ratio of NO2 N/NH4+-N was about 1.06 and the conversion rate was only about 51% Because this value was quite low, the DO, pH and alkalinity parameters in the operation were adjusted to quickly improve the ratio In the proceeding days, the ratio of NO2 N/NH4+-N increased gradually day by day until the ratio reached its highest value on the 27th day, with an of NO2 N/NH4+-N of 1.4 and conversion efficiency of nearly 57% On the 30th day, the ratio of NO2 N/NH4+-N was 1.31, which is similar to the - Partial nitritation (PN): figs and show the loading rate of ammonium to be 0.25 kg NH4+-N/m3.d corresponding to an ammonium concentration of 120±7.5 mg/l After the SWW passed through the UASB tank, the ammonium content increased to 134±7.5 mg/l Nitrification process took place in the PN tank and the ammonium conversion efficiency was about 57% The NO2 N/NH4+-N ratio was about 1.27±0.3 and the highest ratio was 1.53 on the 20th day with an ammonium conversion efficiency of 63% The DO in the PN tank at this stage was only about 0.8-1.0 mg/l, and the pH was in the range of 7.4-8.2 after long retention times to create conditions for AOB growth The NO3 N concentration of the effluent from the PN tank was very low (5±1.2 mg/l) This proved that the process in the PN tank was indeed the nitrification process, and the nitritation process was almost non-existent NO2 /NH4+ ratio Results and discussion The UASB/EGSB-anammox After the loading ammonium was increased to 0.5 kg NH -N/m d, the input theoretical ratio, rate andofthe ammonium conversion efficiency wastewater had a relatively stable ammonium content (123±8.8 mg/l) The ammonium + reached 60% In general, an average NO2 -N/NH4 -N ratio concentration after passing through UASB tank increased to 130±8 mg/l During the first in the range of 1.22±0.2 is suitable for the anammox process few days during the loading process, the ratio of NO2 N/NH4+-N was about 1.06 and the in the EGSB tank conversion rate was only about 51% Because this value was quite low, the DO, pH and 1.8 100 1.6 90 1.4 80 70 1.2 60 50 0.8 40 0.6 30 0.4 20 0.2 Efficiency (%) was adjusted automatically through a pH controller and chemical pump NaHCO3 salt was added to the PN tank to adjust the pH in the range of 7.5-8.5 The goal of the PN tank is to convert a part of NH4+ into NO2- to a NH4+/NO2- ratio of 1/1.32 and to prevent the formation of NO3-, creating the most favourable conditions for the anammox process in the EGSB tank to take place 10 10 12 14 18 20 23 25 27 31 33 37 39 41 44 46 50 52 54 58 60 Time course (day) NO2-/NH4+ ratio Efficiency (%) + + ratio in the survey process Fig NO2-2/NH /NH in the survey process Fig 2 NO 4 ratio Nitrogen removal efficiency: the concentration of input and output nitrogen Nitrogen removal efficiency: the concentration of input compounds of the EGSB tank is shown in Fig Over the first 20 days, the model was and output nitrogen compounds of the EGSB tank is shown operated at a low loading rate of 0.25 kg NH4+-N/m3.d in order to allow the anammox in Fig Over the first 20 days, the model was operated at bacteria to gradually adapt to SWW The removal efficiency of NO2 N increased with aoperation low loading rate kgremoval NH4+-N/m d was in order toonallow time, from theof first0.25 day the efficiency 22% and the 20th day the the anammox to 41.78 gradually to SWW The NH4+-N -N/l removed The average removal efficiency bacteria was 52% with mg NOadapt removal efficiency of NO2 N increased with operation time, from the first day the removal efficiency was 22% and on the 20th day the removal efficiency was 52% with 41.78 mg NO2 N/l removed The average NH4+-N removal efficiency was 37% after 20 days of operation with 18 mg NH4+-N/l removed At the same time, the amount of nitrate produced was 1.8 mg NO3 N This shows that the anammox bacteria began to adapt to the wastewater When the loading rate of ammonium was increased 0.5 kg NH4+-N/m3.d on the 21st day, the NH4+ removal efficiency was 25% and the NO2 N removal efficiency was 27% This indicated that the anammox bacteria cannot adapt to new loads yet After the loading rate increaset, the processing efficiency increased markedly in the following days shown by an adjustment of the NO2 N/NH4+-N ratio March 2020 • Vol.62 Number Vietnam Journal of Science, Technology and Engineering 87 Fig Concentration of input and output nitrogen compounds of the EGSB tank The UASB/EGSB-anammox combined with PVA gel Environmental Sciences | Ecology in the range of 1.0-1.4 which created favourable conditions for the anammox bacteria After 20 days of operation at an ammonium loading rate of 0.5 kg NH4+-N/m3.d, the NH4+ removal efficiency was 64% and the NO2 N removal efficiency was 70% The amount of NO3 N generated was about 8.8% compared to the amount of NH4+-N consumed, which proves that the nitrate reduction process coexisted with anammox process 1.6 + NO2 -/NH4+ ratio removal efficiency was 37% after 20 days of operation with 18 mg NH4+-N/l removed thetheloading ammonium was 0.75 At the When same time, amount ofrate nitrateofproduced was 1.8 mg NOincreased that -N This shows + bacteria3 began to adapt to the wastewater thekg anammox NH -N/m d, the treatment efficiency had a sharp decline 100 90 80 70 60 50 40 30 20 10 1.4 st When the loading rate of ammonium was increased 0.5 kg NH4 -N/m d on the 21 efficiency was over the first few days The NH + removal day, the NH4+ removal efficiency was 25% and the4 NO2 N removal efficiency was 27% -N removal efficiency was 18% mainthe 39% and the NO This indicated that the anammox bacteria cannot adapt to new loads The yet After loading the processing efficiency increased markedly incould the following causerateofincreaset, this situation is that the annamox bacteria not days shown by an adjustment of the NO2 N/NH4+-N ratio in the range of 1.0-1.4 which adapt to theconditions suddenforchange in load InAfter the20following days, created favourable the anammox bacteria days of operation at an + thesteady NH4+ removal wasthe 64% ammonium loading rate of 0.5 kg NHreached the operating conditions state efficiency whereby -N/m d, a and the NO2 N removal efficiency was 70% The amount of NO3 N generated was removal efficiency increased gradually On the last day, the about 8.8% compared to the amount of NH4+-N consumed, which proves that the nitrate performance reached 57 andprocess 69%, with 26 mg NH4+-N/l reduction process coexisted with anammox removed The 0.75 average and mg rate NOof2 N/l -N/m3.d, the When30.5 the loading ammonium was increased kg NH4+removal + The NH4+ removal treatment efficiency had a sharp decline over the first few days performance at this load was 55% (NH4 -N) and 64% was 18% The main cause of this efficiency- was 39% and the NO2 N removal efficiency The amount of could NO3not -Nadapt generated was about 5%In (NO situation2is-N) that the annamox bacteria to the sudden change in load + thecompared following days, conditions aconsumed steady state whereby the removal -N to the theoperating amount of NHreached efficiency increased gradually On the last day, the performance reached 57% and 69%, + with 26In mggeneral, NH4+-N/l and mg NONH The average removal -N/l removed -N concentration was performance 134±5, the30.5input at this load was 55% (NH4+-N) and 64% (NO2 N) The amount of NO3-N generated was 130±8, and 110±10 mg/l for ammonium loading rate of + about 5% compared to the amount of NH4 -N consumed 1.2 0.8 0.6 0.4 0.2 Transformation (%) PN: from Figs and show that the 0.25 kg NH4+-N/m3.d loading rate of ammonium, the input ammonium concentration was 126±10 mg/l The ammonium conversion efficiency was about 58%, and the NO2 N/NH4+-N ratio was 1.16±0.29 On + + problems day, the NOAfter ratio decreased to 0.75 because the system the 7threquired /NHhad ratio than the problem, the NO /NH4 fixing during operation making the conversion rate thfrom ammonium to - nitrite+ lower than increased gradually, and on the 14 day the NO /NH ratio and on the required After fixing the problem, the NO2-/NH4+ ratio increased 2gradually, was ammonium conversion efficiency of 64% + th 1.32 with 14 day the NO2 /NH4 ratio was 1.32 with ammonium conversion efficiency of 64% Time course (day) NO2-/NH4+ratio Transformation performance (%) + Fig NO- 2-/NH ratio in the survey process + Fig NO2 /NH4 ratio in the survey process After increasing the rate loading rate ofup ammonium up 3to d, the After increasing the loading of ammonium to 0.5 kg NH4+-N/m + ammonium conversion efficiency decreased to 51%.conversion The input ammonium was 133±6 0.5 kg NH -N/m d, the ammonium efficiency mg/l and the average NO2-The /NH4+ input ratio wasammonium about 1.25±0.12.was On the 32nd day, the ratio decreased to 51% 133±6 mg/l was 1.32 This ratio is the ideal ratio While the ratio in this period was - theoretical + and the average NO /NH4 inratio was about 1.25±0.12 relatively unstable most of the 2ratios were the range of 1.0-1.4 which meant they were nd On the 32 day, the ratio was 1.32 This ratio is the ideal still suitable for the next process theoretical therate ratio in this period was relatively On days 41ratio to 44, While the loading of ammonium was increased to 0.75 kg NH4+3 unstable most oftothe ratios the showed range that of the 1.0-1.4 an HRT of 4were h Theinresults conversion N/m d corresponding + efficiencymeant of ammonium decreased 51% Thefor ratio NO2-/NH decreased to which they were stilltosuitable theof next process 0.9±0.07 because the sludge did not adapt to the change in loading rate In the following Efficiency (%) Concentration(mg/l) + 44, the loading rate wasratio days,On the days ratio of41 NOto gradually On of the ammonium 58th day, the highest /NH increased d, respectively, the 0.25, 0.5,theand NH4+-N/m In general, input0.75 NH4+-Nkg concentration was 134±5 mg/l, 130±8 mg/l,and and 110±10 efficiency of 65% The average ammonium + reached 1.34 with an ammonium conversion + increased to 0.75 kg NH -N/m d corresponding to an HRT d, respectively, mg/l for ammoniumtreatment loading rate efficiency of 0.25, 0.5, and NH4 -N/m ammonium of0.75 thekgmodel reached 37, conversion efficiency was 58% and the ammonium treatment efficiency of the model reached 37%, 64%, and 55% of h The results showed that the conversion efficiency 64, and 55% respectively Nitrogen removal efficiency: to the 51% concentration of inputofand respectively + of ammonium decreased The ratio NOoutput /NHnitrogen compounds from the EGSB tank is shown in Fig Over the first 20 days, the 4model decreased because adapt to 100 90 -N/m3not d, and the removal was operated to with0.9±0.07 a low loading rate of the 0.25sludge kg NH4+did + 90 80 the change in2 loading rate Inwith theoperation following days, theday, ratio of efficiency of NO and NH4 increased time On the first the removal 80 70 th of NH + was about 42% 35% and the removal efficiency efficiency of +NO was about gradually NO /NH increased On the 58 day, the highest 70 60 60 ratio reached 1.34 with an ammonium conversion efficiency 50 50 of 65% The average ammonium conversion efficiency was 40 40 30 58% 30 20 20 10 10 0 10 12 14 18 20 23 25 27 31 33 37 39 41 44 46 50 52 54 58 60 Time course (day) Eff NH4+ (PN) Eff NH4+ (EGSB) Eff NO2- (PN) Eff NO2- (EGSB) Eff NO3-(PN) Eff NO3- (EGSB) %NH4+ %NO2- Fig Concentration of input and output nitrogen compounds of the EGSB tank The UASB/EGSB-anammox combined with PVA gel PN: from Figs and show that the 0.25 kg NH4+-N/m3.d loading rate of ammonium, the input ammonium concentration was 126±10 mg/l The ammonium conversion efficiency was about 58%, and the NO2 N/NH4+-N ratio was 1.16±0.29 On the 7th day, the NO2-/NH4+ ratio decreased to 0.75 because the system had problems during operation making the conversion rate from ammonium to nitrite lower 88 Vietnam Journal of Science, Technology and Engineering Nitrogen removal efficiency: the concentration of input and output nitrogen compounds from the EGSB tank is shown in Fig Over the first 20 days, the model was operated with a low loading rate of 0.25 kg NH4+-N/m3.d, and the removal efficiency of NO2- and NH4+ increased with operation time On the first day, the removal efficiency of NO2- was about 35% and the removal efficiency of NH4+ was about 42% On the 6th day, the removal efficiency of NO2- increased to 51% and the removal efficiency of NH4+ increased to 56% On the 7th day, the removal efficiency of NO2- unexpectedly dropped to 32.6% and the removal efficiency of NH4+ was about 35% because the NO2-/NH4+ ratio was 0.75 After fixing a problem in the PN tank, the NH4+ and NO2- treatment efficiency increased gradually and became relatively stable The average processing efficiency was about 55% for NH4+ and 55% for NO2- At the same time, the production of NO3was about 6.4% of the influent NH4+ March 2020 • Vol.62 Number Concentration (mg/l) On the 6th day, the removal efficiency of NO2- increased to 51% and the removal efficiency of NH4+ increased to 56% On the 7th day, the removal efficiency of NO2unexpectedly dropped to 32.6% and the removal efficiency of NH4+ was about 35% because the NO2-/NH4+ ratio was 0.75 After fixing a problem in the PN tank, the NH4+ and NO2- treatment efficiency increased gradually and became relatively stable The average processing efficiency was about 55% for NH4+ and 55% for NO2- At the same time, the production of NO3- was about 6.4% of the influent NH4+ 90 100 80 90 Environmental Sciences | Ecology mg NO2 N/l removed Conclusion 80 70 60 + + 3 + Efficiency (%) The UASB/EGSB-anammox system was applied to treat SWW HRTs were surveyed from 12, 6, and h, 60 50 and the ammonium removal efficiencies were 37, 64, and 50 40 55%, respectively The nitrite removal efficiencies were 52, 40 30 30 69, and 64%, respectively The PVA gel added during the 20 20 second phase of the model showed an increase in pollution 10 10 handling and model stability when operating at high loading 0 rates The ammonium removal efficiencies were 56, 68, and 10 12 14 18 20 23 25 27 31 33 37 39 41 44 46 50 52 54 58 60 Time course (day) 60% for HRTs of 12, 6, and h, respectively, and nitrite Eff NH (PN) Eff NH (EGSB) Eff NO - (PN) Eff NO - (EGSB) removal efficiencies were 55, 77, and 73%, respectively Eff NO - (PN) Eff NO - (EGSB) %NH removed %NO - removed This research model can be adapted to higher loads in order Fig of input output nitrogen compounds EGSB tank Fig 5.Concentration Concentration of and input and output nitrogenof compounds of EGSB tank the loading rate of ammonium to 0.5 kg NH +-N/m3.d, the removal to assess its ability to handle critical conditions When increasing 70 2 efficiency of NO2- and NH4+ was relatively stable After 20 days of operation, the highest The authors declare that there is no When increasing loading of ammonium to 0.5 removal efficiency value was the reached on day17,rate with 73% for NH4+-N removal and 81% The average NH +-N removal efficiency was -about 68% and + removal + the regarding the publication of this article -N for NO kg NH2 -N/m d, the removal efficiency of NO2 and NH4 efficiency the last the days highest of this period, average NO2 N removal was relatively stable Afterwas 20about days77% of Over operation, the output of ammonium nitrogen was approximately 14±0.56 mg/l The amount of NO3- REFERENCES + removal value wasNH reached on day17, with 73% N produced efficiency was about 5% of the influent conflict of interest + + for The NHloading -N rate removal andwas 81% for toNO removal The [1] P.K Lieu, et al (2005), “Single-stage nitrogen removal using of ammonium increased 0.752 -N kg NH 4 -N/m d On the first + + was 62% andwas the removal of NH was day, the removal of NO2efficiency average NH4 efficiency -N removal aboutefficiency 68% and the anammox and partial nitriteation (SNAP) for treatment of synthetic - following days, the removal performance increased slowly On the 40% Then,NO over the average -N removal efficiency was about 77% Over landfill leachate”, Japanese Journal of Water Treatment Biology, + 54th day, the effect reached a steady state, and the NH4 -N removal efficiency was about the days this efficiency period, was the about output removal 74%.ofOnammonium the last day, the 41(2), pp.103-112 61% last and the NO2 Nof performancewas reached 63% NH4+-N removal and 75% NO2-NThe removal, with 24.0 nitrogen approximately 14±0.56 mg/l amount of mg [2] M Strous, et al (1997), “Ammonium removal from + and 46 mg NO2was -N/l removed NH4+-N/l NO -N produced about 5% of the influent NH concentrated waste steams with anaerobic ammonium oxidation The loading rate of ammonium was increased to 0.75 kg NH4+-N/m3.d On the first day, the removal efficiency of NO2- was 62% and the removal efficiency of NH4+ was 40% Then, over the following days, the removal performance increased slowly On the 54th day, the effect reached a steady state, and the NH4+-N removal efficiency was about 61% and the NO2 N removal efficiency was about 74% On the last day, the performance reached 63% NH4+-N removal and 75% NO2 N removal, with 24.0 mg NH4+-N/l and 46 (annamox) process in different reactor configurations”, Water Res., 31(8), pp.1955-1962 [3] M.C Schmid, et al (2007), “Anaerobic ammonium-oxidizing bacteria in marine environments: widespread occurrence but low diversity”, Environ Microbiol., 9(6), pp.1476-1484 [4] A.O Sliekers, et al (2003), “Canon and anammox in a gas-lift reactor”, FEMS Microbiology letters, 218(2), pp.339-344 [5] http://www.kuraray-aqua.co.jp/en/product/pvagel.html March 2020 • Vol.62 Number Vietnam Journal of Science, Technology and Engineering 89 ... combination with with PVA PVA gel gel and for the the treatment of The SWW anammox process is applied in combination with PVA gel for the treatment of SWW evaluate the factors that affect the treatment. .. Science, Technology and Engineering 87 Fig Concentration of input and output nitrogen compounds of the EGSB tank The UASB/ EGSB- anammox combined with PVA gel Environmental Sciences | Ecology in the... slaughter slaughter wastewater wastewater treated bycentral usingpipe UASB thesepurpose processes diameter The is made of PVC and is composed combined combined with with EGSB EGSB technologies