Struvite precipitation from anaerobically treated municipal and landfill wastewaters

2002 ◽  
Vol 46 (9) ◽  
pp. 271-278 ◽  
Author(s):  
M. Altinbaş ◽  
C. Yangin ◽  
I. Ozturk
Keyword(s):  
Ammonium Phosphate ◽  
Domestic Wastewater ◽  
Treatment System ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Stoichiometric Ratio ◽  
Magnesium Ammonium Phosphate ◽  
N Removal ◽  
Fenton’S Oxidation ◽  
Fenton's Oxidation

A two-stage treatment system including upflow anaerobic sludge blanket reactor pre-treatment combined with a chemical post treatment system such as magnesium ammonium phosphate (MAP) precipitation was proposed as a comparable alternative to conventional biological treatment. In this study, anaerobically pre-treated domestic wastewater, domestic wastewater mixed with 2% and 3% of leachate by volume and raw leachate were further treated chemically with MAP precipitation. MAP precipitation was both applied at the stoichiometric ratio (Mg:NH4 = PO4; 1:1:1) and above the stoichiometric ratio (1.1:1:1 and 1.1:1:1.1) on domestic wastewater +3% leachate mixture. Maximum NH4-N removal of 68% was achieved at the pH of 9.2 at the stoichiometric ratio, whereas at the same pH value 70 to 72% NH4-N removal was obtained above the stoichiometric ratio. Additional ammonia recovery studies were conducted on Fenton's oxidation applied effluents before MAP precipitation and no significant additional ammonium removal was achieved. However, by the application of Fenton's oxidation high additional COD removals were obtained. Consequently, chemical treatment by MAP precipitation and/or Fenton's oxidation after anaerobic treatment yielded very effective removals for COD and NH4-N in domestic wastewaters + leachate mixtures.

Ammonia recovery from high strength agro industry effluents

2002 ◽  
Vol 45 (12) ◽  
pp. 189-196 ◽  
Author(s):  
M. Altinbas ◽  
I. Ozturk ◽  
A.F. Aydin
Keyword(s):  
Experimental Studies ◽  
Ammonium Phosphate ◽  
High Strength ◽  
Stoichiometric Ratio ◽  
Ammonia Content ◽  
Magnesium Ammonium Phosphate ◽  
Fenton’S Oxidation ◽  
Ammonia Recovery ◽  
Fenton's Oxidation ◽  
Opium Alkaloid

The aim of the study was to investigate ammonia recovery from high strength agro industry effluents involving significant amounts of ammonia, by applying magnesium ammonium phosphate (MAP) precipitation technology. Two types of industrial effluents have been tested in the study. The first plant was an opium alkaloid processing industry and the second one was a baker`s yeast industry. High chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN) and unacceptable dark brown color characterized effluents from both industries. Effluents from the biologically treated opium alkaloid and baker's yeast industries were both applied at the stoichiometric ratio (Mg:NH4:PO4 =1:1:1) and above the stoichiometric ratio (Mg:NH4:PO4 =1.1:1:1.1) to MAP precipitation. NH4 removals of 61-80% were achieved at the pH of 9.2 at the stoichiometric ratio, whereas 83% NH4 removal was obtained at the pH of 9.2 above the stoichiometric ratio. Experimental studies performed on both anaerobically and/or aerobically treated baker`s yeast and opium alkaloid industry effluents have clearly indicated that MAP precipitation was an appropriate treatment option for NH4 removal or struvite recovery from high ammonia content agro industry effluents. Additional ammonia recovery studies were conducted on ozonated and Fenton's oxidation applied effluents and these have also indicated that the amounts of struvite and the quality of MAP precipitate was increased significantly. In this framework, MAP sludge recovered from combined biological and Fenton's oxidation treatment effluents were considered as a more valuable slow release fertilizer for agricultural use.

Nitrite reduction and methanogenesis in a single-stage UASB reactor

2015 ◽  
Vol 72 (12) ◽  
pp. 2236-2242 ◽  
Author(s):  
L. I. Borges ◽  
C. M. López-Vazquez ◽  
H. García ◽  
J. B. van Lier
Keyword(s):  
Domestic Wastewater ◽  
High Strength ◽  
Single Stage ◽  
Nitrite Reduction ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
N Removal

In this study, nitrite reduction and methanogenesis in a single-stage upflow anaerobic sludge blanket (UASB) reactor was investigated, using high-strength synthetic domestic wastewater as substrate. To assess long-term effects and evaluate the mechanisms that allow successful nitrite reduction and methanogenesis in a single-stage UASB, sludge was exposed to relatively high nitrite loading rates (315 ± 13 mgNO2−-N/(l.d)), using a chemical oxygen demand (COD) to nitrogen ratio of 18 gCOD/gNO2−-N, and an organic loading rate of 5.4 ± 0.2 gCOD/(l.d). In parallel, the effects of sludge morphology on methanogenesis inhibition were studied by performing short-term batch activity tests at different COD/NO2−-N ratios with anaerobic sludge samples. In long-term tests, denitrification was practically complete and COD removal efficiency did not change significantly after nitrite addition. Furthermore, methane production only decreased by 13%, agreeing with the reducing equivalents requirement for complete NO2− reduction to N2. Apparently, the spatial separation of denitrification and methanogenesis zones inside the UASB reactor allowed nitrite reduction and methanogenesis to occur at the same moment. Batch tests showed that granules seem to protect methanogens from nitrite inhibition, probably due to transport limitations. Combined COD and N removal via nitrite in a single-stage UASB reactor could be a feasible technology to treat high-strength domestic wastewater.

A new process for the combined treatment of municipal wastewaters and landfill leachates in coastal areas

2002 ◽  
Vol 46 (8) ◽  
pp. 111-118 ◽  
Author(s):  
C. Yangin ◽  
S. Yilmaz ◽  
M. Altinbas ◽  
I. Ozturk
Keyword(s):  
Biological Treatment ◽  
Combined Treatment ◽  
Post Treatment ◽  
Treatment System ◽  
Anaerobic Sludge ◽  
Stoichiometric Ratio ◽  
Landfill Leachates ◽  
Magnesium Ammonium Phosphate ◽  
Ammonia Stripping ◽  
Pre Treatment

One of the most convenient methods for leachate control is to treat landfill leachates with domestic wastewaters. In this framework, a two-stage treatment system including anaerobic pre-treatment combined with a chemical post-treatment system such as ammonia stripping and/or Magnesium Ammonium Phosphate (MAP) precipitation can be comparable with a conventional secondary biological treatment. In this study, 2.5% and 2% of leachate by volume was mixed with domestic wastewater as the feed for the mesophilic Upflow Anaerobic Sludge Bed Reactor (UASBR). pH, feed strength and hydraulic retention time (HRT) were monitored for the evaluation of the performance of the anaerobic process. The HRT's varied from 0.76 to 0.52 d and 58% and 85% COD removal efficiencies were obtained at Organic Loading Rates (OLR) of 0.63 and 2 kg COD/m3.d respectively. The average biomass (VS) concentration in the reactor increased from 40 g/l to 50 g/l during the study. Effluents from the UASBR were further treated chemically either with lime for ammonia stripping or with MAP precipitation. MAP precipitation was applied both at the stoichiometric ratio (Mg:NH4:PO4 = 1:1:1) and above the stoichiometric ratio (Mg:NH4:PO4 = 1:1:1.3). Maximum NH4 removal of 66% was achieved at the pH of 9.3 at the stoichiometric ratio, whereas 86% NH4 removal was obtained at the pH of 9.3 above the stoichiometric ratio. Alternatively, ammonia stripping was applied either to the effluents directly taken from the anaerobic reactor or to the effluents to which MAP precipitation was applied stoichiometrically. Ammonia stripping was conducted for 24 h and 89% NH4 removal was observed at the end of 24 h. Consequently, this study indicates that anaerobic pre-treatment combined with chemical post-treatment (MAP) produced high quality of effluent comparable to the conventional biological treatment especially in terms of N and P levels.

Induced Magnesium Ammonia Phosphate Precipitation to Prevent Incrustations and Measures for Phosphorus Recovery

2006 ◽  
Vol 1 (3) ◽  
Author(s):  
Bernd Heinzmann ◽  
Gerd Engel
Keyword(s):  
Carbon Dioxide ◽  
Ammonium Phosphate ◽  
Phosphorus Recovery ◽  
Anaerobic Sludge ◽  
Digested Sludge ◽  
Magnesium Ammonium Phosphate ◽  
Limit Values ◽  
Precipitation Product ◽  
Washing Process ◽  
Grass Growth

In 1994 for the first time massive incrustations in the centrifuges treating the digested sludge were detected in some wastewater treatment plants (WWTP’s) of the Berliner Wasserbetriebe, which were, as was found out later, mainly due to the precipitation of white MAP (magnesium ammonium phosphate = struvite) deposits with small portions of different calcium phosphate compounds. The reason for this was the over saturation of the digested sludge and the process water (from the separated centrate of the digested sludge) with carbon dioxide, the spontaneous release of or degassing of carbon dioxide, causing the pH to increase, thus altering the solubility equilibrium, and facilitating crystallisation, resulting in deposits (incrustations) on the walls. Obviously, the wastewater purification process used, with enhanced biological phosphorus removal and concentrated streams of digesting sludge, favours the formation of incrustations during sludge treatment. These incrustations were the cause of a lot of operational problems. To prevent incrustations, modifications in the process engineering technology have been applied after several studies and trials. Deliberate extraction of the CO2, e.g. by air injection through a fine-bubble surface aeration system at the bottom of the digested sludge storage tank just before the centrifuges, causes the pH to rise to approx. 8 and thus to cause induced struvite precipitation. This technology enables a precipitation product suitable for recycling to be generated and separated from the anaerobic sludge using a hydro-cyclone. A subsequent second hydro-cyclone stage allowed a further increase in the P-concentration to approx. 40 kg/m3, giving a yield of phosphorus of 20 %. This corresponds with P-load of approx. 316 kg/day and amounts to 18 % of the P inlet load in the WWTP Waßmannsdorf. It was shown that this experimental process is in principle suitable for the separation of the MAP precipitation product in the anaerobic sludge. A complete washing process for the raw MAP is not yet installed, and furthermore, to find the best sizes of nozzles in the hydro-cyclones and most effective pressures tests will have to be carried out soon at pilot level. A comparison with the minimum nutrients content for different kinds of fertiliser (super-phosphate, dicalcium-phosphate with magnesium, NP-fertiliser) defined by the German Fertiliser Regulations, shows that the precipitated MAP is within the range of other legally certified fertilisers. The MAP showed contaminant levels 5 times or more below the limit values of the German Sewage Sludge Ordinance. The MAP precipitation product is very soluble in different solvents (from ammonium chloride to hydrochloric acid). This implies that the precipitation product can be used as a long term fertilizer. In two test soils having a pH value of 6.6 and 7.1, the MAP precipitation solid was tested using standard ryegrass and showed good phosphorus availability from this material leading to a good grass growth.

Combined Treatment of Domestic Wastewater using Anaerobic and Solar Photocatalytic Treatment

2009 ◽  
Vol 44 (4) ◽  
pp. 393-398 ◽  
Author(s):  
J. Rajesh Banu ◽  
Sudalyandi Kaliappan ◽  
Khac-Uan Do ◽  
Arthur James ◽  
Ick Tae Yeom
Keyword(s):  
Combined Treatment ◽  
Domestic Wastewater ◽  
Anaerobic Treatment ◽  
Stage I ◽  
Stage Ii ◽  
Photochemical Oxidation ◽  
Upflow Anaerobic Sludge Blanket ◽  
Treated Wastewater ◽  
Anaerobic Sludge ◽  
Working Volume

Abstract The present study utilizes anaerobic and solar photocatalytic methods to treat domestic wastewater. For stage I, a granulated hybrid upflow anaerobic sludge blanket reactor (HUASB) with a working volume of 5.9 L was used. It was run in a recirculation mode for 3 days called "one cycle," and 30 cycles were run to find out the stability of the anaerobic treatment. During stage I anaerobic treatment, 90% of the chemical oxygen demand (COD) was removed, and it increased with an increase in digestion period for each cycle. Volatile fatty acids did not cause any operational problems during the stage I anaerobic treatment, being in the range of 280 to 90 mg/L. Stage I treated wastewater was subjected to a stage II solar photocatalytic oxidation method. The optimum pH and catalyst loading for the solar photochemical oxidation were found to be 5 and 200 mg/L, respectively. Stage II, treatment at an optimized condition, removed 66% of organics from the stage I treated wastewater. The combined COD removal due to the combination of these two technologies was found to be 96%.

Mathematical modeling of upflow anaerobic sludge blanket (UASB) reactor treating domestic wastewater

2013 ◽  
Vol 67 (1) ◽  
pp. 24-32 ◽  
Author(s):  
Tarek Elmitwalli
Keyword(s):  
Chemical Oxygen Demand ◽  
Dynamic Model ◽  
Empirical Model ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Model Based ◽  
Anaerobic Sludge Blanket

Although the upflow anaerobic sludge blanket (UASB) reactor has been widely applied for domestic wastewater treatment in many developing countries, there is no sufficient mathematical model for proper design and operation of the reactor. An empirical model based on non-linear regression was developed to represent the physical and chemical removal of suspended solids (SS) in the reactor. Moreover, a simplified dynamic model based on ADM1 and the empirical model for SS removal was developed for anaerobic digestion of the entrapped SS and dissolved matter in the wastewater. The empirical model showed that effluent suspended chemical oxygen demand (CODss) concentration is directly proportional to the influent CODss concentration and inversely proportional to both the hydraulic retention time (HRT) of the reactor and wastewater temperature. For obtaining sufficient CODss removal, the HRT of the UASB reactor must be higher than 4 h, and higher HRT than 12 h slightly improved CODss removal. The dynamic model results showed that the required time for filling the reactor with sludge mainly depends on influent total chemical oxygen demand (CODt) concentration and HRT. The influent CODt concentration, HRT and temperature play a crucial role on the performance of the reactor. The results indicated that shorter HRT is needed for optimization of CODt removal, as compared with optimization of CODt conversion to methane. Based on the model results, the design HRT of the UASB reactor should be selected based on the optimization of wastewater conversion and minimization of biodegradable SS accumulation in the sludge bed, not only based on COD removal, to guarantee a stable reactor performance.

Integration of sulphate reduction, autotrophic denitrification and nitrification to achieve low-cost excess sludge minimisation for Hong Kong sewage

2006 ◽  
Vol 53 (3) ◽  
pp. 227-235 ◽  
Author(s):  
G.N. Lau ◽  
K.R. Sharma ◽  
G.H. Chen ◽  
M.C.M. van Loosdrecht
Keyword(s):  
Low Cost ◽  
Nitrate Solution ◽  
Integrated Treatment ◽  
Treatment System ◽  
Upflow Anaerobic Sludge Blanket ◽  
Synthetic Wastewater ◽  
Anaerobic Sludge ◽  
Autotrophic Denitrification ◽  
Excess Sludge ◽  
Anaerobic Reactor

An integrated anaerobic–aerobic treatment system of sulphate-laden wastewater was proposed here to achieve low sludge production, low energy consumption and effective sulphide control. Before integrating the whole system, the feasibility of autotrophic denitrification utilising dissolved sulphide produced during anaerobic treatment of sulphate rich wastewater was studied here. An upflow anaerobic sludge blanket reactor was operated to treat sulphate-rich synthetic wastewater (TOC = 100 mg/L and sulphate = 500 mg/L) and its effluent with dissolved sulphide and external nitrate solution were fed into an anoxic biofilter. The anaerobic reactor was able to remove 77–85% of TOC at HRT of 3 h and produce 70–90 mg S/L sulphide in dissolved form for the subsequent denitrification. The performance of anoxic reactor was stable, and the anoxic reactor could remove 30 mg N/L nitrate at HRT of 2 h through autotrophic denitrification. Furthermore, sulphur balance for the anoxic filter showed that more than 90% of the removed sulphide was actually oxidised into sulphate, thereby there was no accumulation of sulphur particles in the filter bed. The net sludge productions were approximately 0.15 to 0.18 g VSS/g COD in the anaerobic reactor and 0.22 to 0.31 g VSS/g NO3−-N in the anoxic reactor. The findings in this study will be helpful in developing the integrated treatment system to achieve low-cost excess sludge minimisation.

Theoretical/Experimental Study of an Upflow Anaerobic Sludge Blanket Reactor Treating Domestic Wastewater

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Maria Gorethe Sousa Lima ◽  
Severino Rodrigues de Farias Neto ◽  
Antonio Gilson Barbosa de Lima ◽  
Flávio César Brito Nunes ◽  
Luciano de Andrade Gomes
Keyword(s):  
Experimental Study ◽  
Suspended Solids ◽  
Fluid Dynamic ◽  
Total Concentration ◽  
Domestic Wastewater ◽  
Pilot Scale ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Ansys Cfx ◽  
Anaerobic Sludge Blanket

This work reports a theoretical and experimental study to evaluate the fluid dynamic of an Upflow Anaerobic Sludge Blanket reactor (UASB), treating domestic wastewater in a pilot scale. Simulations were developed using the Ansys CFX 10.0. For validating the numerical results, an experimental study was conducted by monitoring the total concentration of suspended solids in the effluent and pressure along the reactor. The comparative analysis between the numerical and experimental results of the pressure and sludge concentration in the outlet of the reactor presented few differences, being considered satisfactory.

Anaerobic Treatment of Domestic Wastewater in Small Scale UASB Reactors

1993 ◽  
Vol 27 (9) ◽  
pp. 75-82 ◽  
Author(s):  
J. J. Bogte ◽  
A. M. Breure ◽  
J. G. van Andel ◽  
G. Lettinga
Keyword(s):  
Organic Matter ◽  
The Netherlands ◽  
Volatile Fatty Acids ◽  
Domestic Wastewater ◽  
Anaerobic Treatment ◽  
Gas Production ◽  
Upflow Anaerobic Sludge Blanket ◽  
Small Scale ◽  
Anaerobic Sludge ◽  
Uasb Reactors

A survey was made on the feasibility of on-site anaerobic treatment of domestic wastewater from small scale emissions in The Netherlands. Three 1.2 m3 UASB-reactors (Upflow Anaerobic Sludge Blanket) were tested in different rural locations. The survey made clear that the efficiency of the process is highly dependent on the reactor temperature. Below 12 °C purification was predominantly based on settling, while above 12 °C microbial degradation of organic matter increased. Efficiencies for the removal of total COD and BOD of two of the reactors ranged between 33 and 60%, equalising well performing septic tanks. In one of the reactors the average production of biogas, with a methane content of 78%, was 67 liters per day. Complete transformation of volatile fatty acids (VFA) into biogas was achieved during 3 to 4 months a year at temperatures above 15 °C. In this period, during the second year of operation, the average efficiencies for COD and BOD removal were 60 and 72% respectively, while the maximum gas production reached 300 liters per day. In the latter period the mineralisation rate exceeded the input rate of organic matter, resulting in a decrease of settled material in the reactor. The possibility of high efficiencies during summertime in The Netherlands and the positive results of similar experiments in Indonesia and Latin America lead to the conclusion that anaerobic digestion is a promising process for the (pre-)treatment of domestic waste water in (sub)tropical countries.

Nine years of full-scale anaerobic–aerobic treatment experiences with fermentation industry effluents

1995 ◽  
Vol 32 (12) ◽  
pp. 131-139 ◽  
Author(s):  
T. Çiftçi ◽  
I. Öztürk
Keyword(s):  
Biogas Production ◽  
Energy Requirement ◽  
Treatment Plant ◽  
Full Scale ◽  
Treatment System ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Aerobic Treatment ◽  
Second Stage ◽  
Anaerobic Reactors

This paper presents the results of nine years of experience in design and operating of full-scale anaerobic-aerobic treatment plants in a fermentation industry producing baker's yeast from sugarbeet molasses. The PAKMAYA Izmit Factory has a large two-staged treatment plant since 1986: anaerobic first stage and aerobic second stage. The anaerobic reactors were constructed as Upflow Anaerobic Sludge Blanket Reactors (UASBR) with internal and external sludge recirculation facilities. Average COD removals remain in the range of 75% in the mesophilic anaerobic stage. Average daily biogas production rates are as high as 20,000 m3/day. This treatment plant is one of the largest in the world in terms of biogas production. Similar systems were constructed later in two other factories of the same company (Cumaova-Bolu, Kemalpasa-Izmir). The biogas conversion yield is about 0.65 m3 per kg COD removed. The energy produced from the biogas used in the boiler houses is about 35% of the total energy requirement of the factory. The effluents from the anaerobic first stage are fed to the subsequent aerobic treatment system by mixing with low strength effluents of the factory. The aerobic second stage was designed and operated as an extended aeration activated sludge system. The COD removals of the aerobic stage are averaging at about 60 to 75%. This paper also discusses the operating problems encountered in the various stages of the treatment system and their solutions during the nine years of full-scale operation in three different treatment plants of PAKMAYA.

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