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Research Article

Received: 21 December 2011 Revised: 25 February 2012 Accepted: 27 February 2012 Published online in Wiley Online Library: 16 April 2012

(wileyonlinelibrary.com) DOI 10.1002/jctb.3803

Simultaneous removal of TOC and TSS in swine

wastewater using the partial nitritation process

Marina Celant De Pra,a Airton Kunz,b Marcelo Bortoli,c Tiago Perondid

and Angelica Chinia

Abstract

BACKGROUND: Considering biological nitrogen removal, the partial nitritation connected with the anaerobic ammoniumoxidation (anammox) process is a promising alternative for nitrogen elimination at high loading rates. The objective ofthe present study was to evaluate the establishment and operation of a partial nitritation process in an airlift reactor withsimultaneous removal of total organic carbon and suspended solids using swine wastewater.

RESULTS: The partial nitritation reactor was inoculated with a nitrifying sludge at 2.1 gTSS L1 and fed with an UASB reactoreffluent. High organic carbon loading rates, above 2 kgTOC m3 d1 have been shown to be potential inhibitors of the partialnitritation process due to competition between autotrophic and heterotrophic bacteria. In this study, the partial nitritationprocess was established using undiluted swine wastewater, with HRT of 24 h, 1.84 mgO2L

1 (SD = 0.41) DO, loading rate of1.14 gTOC L1 d1 and 0.91 gN-NH3L

1 d1 for more than 100 consecutive days. At the same time, the system proved to be aneffective tool in TOC and TSS removal, reaching 84.9% (SD= 9.3) and 83.1% (SD= 0.1), respectively.

CONCLUSION: This result enhances partial nitritation application as a technology for high load nitrogen converting, and allowsthe possibility of connection with anammox reactors.c 2012 Society of Chemical Industry

Keywords: suspended solids; anammox; swine effluent; nitrogen removal; organic carbon

NOTATIONCLR: Carbon loading rate (kgTOC m3 d1)

COD: Chemical oxygen demand (mg L1)

DO: Dissolved oxygen (mgO2L1)

FA: Free ammonia (mgNH3L1)

FNA: Free nitrous acid (mgHNO2 L1)

NPE: Nitrite production efficiency (%)

NPR: Nitrite production rate (kgNO2 N m3 d1)

TN: Total nitrogen (mg L1)

TOC: total organic carbon (mg L1)

TSS: total suspended solids (mg L1)

Amax = maximum growth rate of autotrophic ammonia

oxidizing bacteria (d1)

Hmax = maximum growth rate of aerobic heterotrophic

bacteria (d1)

INTRODUCTIONCurrently, the supply chains of different product areas are under

pressure due to the environmental impacts they can exert.

Pig farming has emerged as one of the largest chains in the

agribusiness, and although it has significant economic and social

importance, it is considered one of the main livestock activities

with high potential environmental impact. The main challenge

for swine wastewater management comes from the large volume

of liquid effluent generated by this concentrated animal feeding

operation (CAFO)and thehigh concentration of nutrients, such as

nitrogen, contained in swine manure.1 These aspects, associated

with inadequate management, cause impacts on aquatic and

terrestrial ecosystems, such as eutrophication of lentic and lotic

environments, and increase the nutrient and metal concentration

in the soil.

In recent years, new technologies have been developed or

adapted to treat swine wastewater to remove organic matter

and nitrogen compounds.2,3,4 Considering the biological removal

of nitrogen, partial nitritation of the anaerobic ammonium

oxidation (anammox) process, represented by Equations (1) and

(2), is a promising alternative for nitrogen elimination at high

loading rates. Usually, biological treatment for nitrogen removal

Correspondence to: Marina Celant De Pr a, Department of Environmental

Engineering, Universityof Contestado, Conc ordia, SC, Brazil.E-mail: [email protected]

This article was published online on 16 April 2012. An error was subsequently

identifiedin equation(1). Thisnoticeis includedin theonlineand printversions

to indicate that both have been corrected25 July 2012.

a Department of Environmental Engineering, University of Contestado,

Conc ordia, SC, Brazil

b Embrapa Swineand Poultry, Conc ordia, SC, Brazil

c Department of Chemical Engineering, Federal University of Santa Catarina,

Florianopolis, SC, Brazil

d Departmentof Biological Sciences, West Universityof Santa Catarina,Joacaba,

SC, Brazil

J Chem Technol Biotechnol2012; 87: 1641 1647 www.soci.org c 2012 Society of Chemical Industry

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www.soci.org M Celant De Praetal.

involves conventional autotrophic nitrification and heterotrophic

denitrification. However, if used, this process requires large

amounts of oxygen and alkalinity to complete the removal cycle.5

In the anammox process, nitrite serves as the final electron

acceptor in ammonia oxidation to produce gaseous nitrogen

(N2) under anaerobic conditions, according to the stoichiometry

shown in Equation (2).6 This process offers several advantages

over conventional nitrificationdenitrification systems, including

higher nitrogen removal rate, lower sludge production and less

space requirement.7,8

For anammox process application, previous partial nitritation

is necessary to prepare the effluent to feed the anammox reactor.

In the partial nitritation process, it is necessary to generate

NH4+/NO2

at stoichiometric ratio for anammox, as shown in

Equation (1). The effectiveness of the process is directly linked

to the capacity of ammonia oxidizing bacteria (AOB) to oxidize

ammonia to nitrite and the simultaneous inhibition of nitrite

oxidizing bacteria (NOB) which oxidize nitrite to nitrate. Although

the ammonium/nitrite theoretical anammox stoichiometric ratio

is 1 : 1.32 (Equation (2)), it is easier to adjust the ratio to 1 : 1

(Equation (1)) considering the higher nitrite toxicity to anammox

bacteria than ammonium.10

Thus, as a pretreatment for feedingthe anammox reactor, partial nitritation should limit the amount

of ammonia oxidized by approximately 50%.

NH4+ + 0.86O2 0.57NO2

+ 0.43NH4+

+ 0.58H2O+ 1.12H+ (1)

NH4+ + 1.32NO2

+ 0.066HCO3 + 0.13H+ N2

+ 0.26NO3 + 0.066CH2O0.5N0.15 + 2H2O (2)

However,as a result of the involvement of complex biochemical

reactions and several microorganisms in the process, this

relationship can be difficult to maintain. Forthis, thephysiological

differences between the AOB and NOB are extremely important

in the stability of the partial nitritation process. Because the NOBare more sensitive than AOB under certain concentrations of free

ammonia and free nitrous acid,11 under limited concentrations

of dissolved oxygen (DO)12,13 and also have a lower growth rate

above 20 C,14,15 partial nitritation can be achieved by controlling

the pH, DO, temperature and hydraulic retention time (HRT).

Previous studies report that the overall efficiency of nitrogen

removalin the connected process of partial nitritation+anammox

was limitedby thefirst stage of partial nitritation.3 As known, swine

wastewater contains a high organic content as well as a high total

suspended solid concentration.16,17 Significant negative effects of

organic matter on anaerobic ammoniumremoval in the anammox

reactors have been reported in some studies.17,18,19 When organic

matter coexists with ammonium and nitrite, anammox bacteriagrowth can be suppressed by rapid growth of heterotrophic

denitrifiers due to the competition for nitrite (electron acceptor)

and living space in the reactor. Therefore, when a large amount of

suspended solids is brought into the anammox reactor, this may

attach itself to the biofilm and consequently, nitrogen removal

efficiencies may decrease.9 This shows the importance of the

operational control in the partial nitritation process to maintain

the effluent stability to avoid causing inhibition or decreasing the

nitrogen removal efficiency in the anammox process.

In the present study, the main objective was to establish and

evaluate the partial nitritation process in an airlift reactor system

with simultaneous removal of total organic carbon and total

suspended solids from swine wastewater.

MATERIAL AND METHODSSwine wastewater

The swine effluent was collected from an upflow anaerobic sludge

blanket (UASB) reactor from a swine manure treatment system

(SMTS) located at Embrapa Swine and Poultry experimental facili-

ties,Concordia,SC,Brazil.1The characteristics of the swine wastew-

ater were: pH 7.9, 30008000 mg L1 TSS, 15006500 mg L1

TOC, 25004500 mg L1 BOD5, 5000 8000 mgCaCO3L1 alkalin-

ity, 15002000 mg L1 TN, 900 1500 mg L1 NH3-N and NO2-N

and NO3-N were not detectable.

Experimental set-up

The experimental system (Fig. 1) consisted of a 5 L glass reactor

with a swim-bed biofringe material as biomass carrier.20 The

reactor temperature control and aeration apparatus consisted of

an airpump (BigAir, A230)and ceramicair diffusers. A pH controller

(S2123-6606, Sincrontec) was connected to the system and the

reactor was fed using a peristaltic pump (Cole-Parmer Master Flex

HV-07 553-70) operated at a flow rate of 5 L d1 . An Imhoff cone

was used in the reactor output as settling tank.

Reactor start-up and operation conditions

The partial nitritation (PN) reactor was inoculated with a nitrifying

sludge collected froman experimental reactor located at Embrapa

Swine and Poultry laboratory at 2.1 gSS L1. The reactor

temperature was kept at 35 C and the pH maintained between

7.6 and 7.8 using NaOH 1 mol L1 to supplement alkalinity. For

the system start-up, the influent was diluted with tap water at

25% (v/v) and its concentration was increased according to the

stability of the nitritation process until it reached 100% (v/v) of

influent. In other words, for each increase in concentration, the

completenitritationprocesswas expectedto adapt before making

new progress.

Analytical methods

Ammonia (NH3-N) was analyzed potentiometrically using a

selective electrode method.21 Nitrite (NO2-N) and nitrate (NO3

-

N) were determined based on a colorimetric method21 using

a flow injection analysis system (FIAlab 2500). Alkalinity was

determined using the titrimetric method21 (Titronic T-200 semi-

automatic) and expressed in mgCaCO3L1. TN and TOC were

analyzed performed usinga TOC analyser (Multi C/N 2100,Analytik

Jena). The pH and DO were determined using a pH meter (S123-

6606, Sincrontec) and a DO meter (55, YSI), respectively.

RESULTS AND DISCUSSIONStart-up and influence of TOC on partial nitritationThe PN reactor was operated for 400 days without interruption.

The performance of nitrogen and time course of carbon loading

rates in the PN reactor are shown in Fig. 2. Note that all values

given in this study are given as average plus standard deviation

(SD).

Depending on the swine wastewater characteristics and the

reactor operation conditions, additional nitrogen conversions

may occur, including the oxidation of nitrite to nitrate. The

reactor was operated at 24 h of HRT and the temperature was

kept at 34.3 C (SD = 0.8) to favor the growing of AOB due to

temperatureand wash outof NOBin thereactor.22,23 Satisfactorily,

the concentrations of NO3-N concentrations were not detected

wileyonlinelibrary.com/jctb c 2012 Society of Chemical Industry J Chem Technol Biotechnol2012; 87: 16411647

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Simultaneous removal of TOC and TSS in swine wastewater www.soci.org

Figure 1. Partial nitritation reactor schematic diagram.

Figure 2. (a) Time course of carbon loading rates and nitrite production rates. (b) Time course of nitrogen concentrations in the PN reactor during theexperiment.

during the experiment (Fig. 2(b)), indicating that NOB activity was

successfully inhibited.

During start-up, the effluent used to feed the system was

diluted at 25% (v/v) to favor the partial nitritation process and

then gradually increased to 100% (v/v) according to the stability

process.On day25 of reactoroperation,after an adjustment period

of approximately 15 days at a concentration of approximately

300 mg L1 NH3-N, the nitrite accumulation was stable in the

system, allowing an increase in concentration. After reaching a

75% dilution (v/v), working with a concentration of approximately

700 mg L1 NH3-N in the influent, day 90, the ammonia oxidation

stopped (Fig. 2(b)), due to the high organic CLR in the influent

(Fig. 2(a) and Fig. 3(a)).

Owing to nitrifying bacteria are autotrophic, they cannot

incorporate exogenous organic compounds, because they obtain

energy from oxidation of inorganic compounds.24 Still, the

maximum growth rate of autotrophic nitrifying (Amax) is much

lower than the growth rate of heterotrophic bacteria (Hmax).

Wiesmann (1994)25 reportedHmax= 7.2 d1 for the growth rate

of aerobic heterotrophic bacteria and Amax = 0.77 d1 for the

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Figure 3. (a) Time course of total organic carbon concentrations. (b) Time course of suspended solid concentrations in the PN reactor during theexperiment.

growth rate of autotrophic ammonia oxidizing bacteria. This large

difference in growth rates, coupled with the carbon availability

and rapid growth of the heterotrophic bacteria, developed the

competition for living space in the PN reactor, suppressing the

growth of AOB which is slower. Therefore, when high organic

matter coexists with ammonium, the AOB cannot compete with

heterotrophic bacteria, because it tends to be inhibited and the

partial nitritation performance is suppressed.

For most of thetime, at lowCLR, there was simultaneous partialammonia nitrification and heterotrophic activity, showing that

both processes could coexist in the PN reactor without inhibition,

as shown in Fig. 2 during the VIII, IX and X phases and in Fig. 3(a).

However, when the CLR increased, the AOB activity tended to

decrease. Thiswas becausethe fractionof nitrifyingmicroorganism

activity decreased as the TOC : N ratio increased, which caused

competition between the heterotrophic and autotrophic bacteria

foroxygenand nutrients. Carbon loadingrates above 2 kgTOCm3

d1 negativelyaffected the partial nitritationprocess performance,

as confirmed by low ammonia oxidation and consequently, low

NPRs obtained during the 90 120 days of operation (Fig. 2, phase

III). It was observed that during phases IV and V, the TOC loading

rate was very close to 2 kg m3 d1, obtaining an average of1.42 kg m3 d1 (SD = 0.5) and positively keeping stable rates

of nitrite production (Fig. 2(a)) and ammonia oxidation (Fig. 2(b))

in the reactor. However, when these loads were greater than

2 kg m3 d1, achieving 3.9 kg m3 d1 during phase VI, for

example (Fig. 2(a)), the nitrite production rates were limited,

showing the inhibition of ammonia oxidation and decreased AOB

due to heterotrophic competition. Thus it was chosen to work

with a safe CLR, less than 2 kgTOC m3 d1, controlled by swine

wastewater dilution so as not to influence nitrite production and

consequently the partial nitritation process.

Thus, operationalconditions have to be controlledto get a good

balance between AOB and heterotrophiccommunities, mainly the

CLRappliedtothefeedingsystem,becausethatcanfavororinhibit

the autotrophic bacteria responsible for ammonia oxidation.

TOC and TSS removal characteristics

Figure 3(a)shows thetime coursesof TOC concentrations in thePN

reactor. Since the nitrogen concentration was increased gradually,

the TOC concentrations increased proportionally, except in times

of TSS fluctuation in the influent concentration or transition to a

new batch of swine wastewater.

The information on the performance of the anammox process

operated under a relatively higher organic content and high

nitrogen loading rate is limited. However, some studies have

reported that anammox bacterial growth was significantly

suppressed by denitrifying communities under high organic

matter content due to the weaker competition for nitrite (electron

acceptor) and living space.17,18,19 Tang etal. (2011)7 observed

that COD concentrations above 300 mg L1 tended to reduce the

nitrite consumption via the anammox process and denitrification

became the dominant route for nitrite removal; while Yamamoto

etal. (2011)26 studied biological nitrogen removal in an anammox

reactor and reported that although 200 mg L1 of TOC remained

in the effluent of the partial nitritation reactor, the anammoxnitrogen removal rate was not significantly decreased.

In the present study, TOC concentrations in the effluent of the

PN reactor remained stable, even with high variability in swine

wastewater concentrations. The average was 147.93 mgTOC L1

(SD= 88.96) throughout the experiment. It should be noted that

even in the period when the autotrophic bacteria were inhibited

in thePN reactor,TOC removal remainedhigh. Theglobal average

TOC efficiency was 84.9% (SD = 9.3) throughout the experiment

that confirmed the strong activity of the heterotrophic bacteria

responsible for aerobic degradation of organic matter in the

reactor. In addition, the TOC concentrations shown in Fig. 3(a)

were lower than those found by other authors using a similar

configuration, which maximized the use of this effluent.9


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Figure 4. (a) Time course of ammonia removal efficiency and nitrite production efficiency after 200 days. (b) Time course of DO concentrations in the PNreactor after 200 days.

Figure 3(b) shows the time courses of TSS concentrations in the

influent and effluent of the PN reactor. When a large amount of

suspended solids is placed in the anammox reactor, it can attach

itself to the biofilm, and as a result, nitrogen removal efficiencies

can decrease.9 Satisfactorily, throughout the operationperiod, the

reactor showed TSS removal efficiency of 83.1% (SD = 0.1), fed

with 1725.1 mgTSS L1 (SD = 1298.25), generating an effluent

with 197.0 mgTSS L1 (SD = 91.32). The need for different swine

wastewater dilutions can explain the high variation in the TSS andTOC concentrations in the PN reactor influent.

Performance and achieving partial nitritation by DO control

Considering that degradative processes are focused on oxidation

reactions, a very important variable in the nitrification process

is dissolved oxygen. Because gaseous oxygen is the final

electron acceptor in the nitritation stoichiometry reaction, its

concentration can be decisive in the rates of ammonia removal

and nitrite production. Thus,we chose to use the dissolvedoxygen

concentration as an operational parameter for partial nitritation

control.

Figure 4(a) shows the time courses of ammonia removal

efficiency (ARE) and nitrite production efficiency (NPE) in thePN reactor. Previous studies have reported that the specific

growth rate of the AOB population increased with increase in

the DO concentration,12,27 favoring the metabolic activity of these

bacteria. This could be seen in the PN reactor when working with

the DO available, 3.32 mg L1 (SD = 0.76), reaching complete

nitritation at several times, allowing all NH3-N to be converted to

NO2-N, resulting in ARE and NPE averages of 88.2% (SD = 0.11)

and 74.3% (SD= 0.21), respectively, as shown in Fig. 4(a) at 200 to

300 days of operation.

Figure 4(b) shows the time courses of DO concentrations in

the PN reactor. The results obtained by some researchers 27,28,29

showed that oxygen concentration was a limiting factor for the

ammonia oxidation rates, and therefore, could be used as an

operational strategy for partial nitritation control. In this study, the

global average DO concentration in the reactor was 2.96 mg L1

(SD= 0.94). However, these values were progressively reduced to

achieve stability of the partial nitritation process. As a result, at a

DO concentration of 1.84 mg L1 (SD = 0.41), after the 300 days

(Fig. 4), the ARE and NPE remained most of the time between

40 and 60%, stabilizing the partial nitritation process, working

with loading rates of 1.14 kgTOC m3 d1 and 0.91 kgNH3-N

m3

d1

, which is very satisfactory when working with real swinewastewater considering the variability in influent.

The average ARE during the stability period was 50.5% (SD =

12.3), while the average NPE was 44.5% (SD = 14.6) (Fig. 4(a)),

and this stability was maintained for more than 100 consecutive

operational days. The system was also efficient for the selective

inhibition of NOB keeping the ratio NO2/(NO2

+NO3) at0.998

% (SD = 0.005). This means no nitrification occurred in the PN

reactor and the ammonia was oxidized only to nitrite by the

AOB activity. If produced, nitrate can serve as a substrate to

promote denitrification competition and will damage subsequent

anammox reactions. Therefore, nitrite is the only product of

ammonia oxidation that is a positive response of the partial

nitritation process.

Equation (3) shows the stoichiometry of the nitrification

reaction.30 The stoichiometric ratio between the molecular

weights of ammonium ion and oxygen is 4.57 mgO2 for each

mgNH4+ oxidized, while in thepartial nitritation process only 1.71

mgO2 for each mgNH4+ oxidized (Equation (1)) are required. On

the other hand, for the aerobic oxidation of organic matter 1.42

mgO2mg1C5H7NO2 are needed, represented by Equation (4).

30

In thePN reactor,the influent TOCconcentrations vary much more

than the ammonium concentrations and even heterotrophic bac-

teria have a lower oxygen consumption than the autotrophic

bacteria; depending on the carbon concentrations available, the

DO concentrations required may increase or decrease in the

reactor. Therefore, higher TOC concentrations in the influent


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Figure 5.Time course of (a) free ammonia and (b) free nitrous acid concentrations.

increase the competition for oxygen between autotrophic and

heterotrophic bacteria in the PN reactor.

NH4+ + 2O2 NO3

+ H2O+ 2H+ (3)

C5H7NO2 + 5 O2 5 CO2 + NH3 + 2 H2O (4)

Considering the simultaneous activity of heterotrophic bacteria

and the high removal efficiency of TOC in the PN reactor, theDO concentration used for the process stability proved to be an

economical strategy because their low values reduced aeration

costs compared with the conventional nitrification/denitrification

process. Furthermore, the reactor had a distinct advantage in

keeping the coexistence of the autotrophic and heterotrophic

process in the same environment, working with high rates of

TOC and TSS removal and still with lower oxygen consumption

compared with conventional processes.

Effect of free ammonia and free nitrous acid

Certain concentrations of FA and FNA exert an inhibitory effect

on the metabolism of nitrifying biomass11,31 and consequently,

strongly influence the oxidation rates of ammonia and nitrite.Their concentrations depend, besides the pH and temperature, on

the ammonia and nitrite concentrations. Thus, even at pH close to

7.0, depending on the ammonia and nitrite concentrations in the

influent, AOB or NOB may be inhibited by the presence of FA or

FNA in excess.

The FA and FNA concentrations were monitored during the

experiment and during inhibition in the partial nitritation process.

Figure 5 shows the time courses of free ammonia and free nitrous

acid levels in the PN reactor. Free ammonia and free nitrous acid

concentrations can be estimated using Equations (5) and (6):11

FNA(HNO2, mg/L)=46

14

[NO2 N

e[2300/(273+T(

C))] 10pH(5)

FA(NH3, mg/L) =17

14

[total ammonia as N] 10pH

e[6344/(273+T(

C))] 10pH(6)

Previous studies11,14,28 demonstrated that the NOB are more

sensitive to FA than the AOB, which can be inhibited at

concentrations from 0.1 10.0 mg L1, and both are severely

inhibited at concentrations higher than 150 mg L1. Therefore,

when theFA concentration is too high, above 150mgNH3L1, i t is

sufficientto inhibit AOBand NOB, andammonia will accumulate in

the system. At lower FA concentrations, up to 10 mgNH3L1, only

NOB will be inhibited and nitrite will accumulate in the system.

In the PN reactor, most of the time, when working at low

TOC concentrations, the FA concentrations remained below these

inhibitory to AOB (Fig. 5(a)), contributing to the partial nitritation

process and operating at FA concentrations inhibitory only for

the NOB. Thus, it was assumed that nitrite oxidizing bacteria had

been inhibited, which also prevented the conversion of nitrite to

nitrate. However, after increasing TOC concentrations between 90

and 120 days of reactor operation, the FA concentrationexceeded

that required for AOB inhibition, showing inhibition in the partial

nitritation process. Figure 5(a) shows that the equilibrium of thesystem was shifted to formation and increasein FA concentrations,

reaching values much higher than the limit for AOB inhibition,

311.07 mgNH3L1 during this period.

According to the stoichiometry of the partial nitritation process,

the oxidation reaction of ammonia to nitrite generates a hydrogen

ion, so it tended to consume alkalinity and consequently tended

to reduce the pH. After the inhibition in the PN reactor due to

competition with heterotrophic bacteria, the partial nitritation

process stopped and ammonia accumulated in the reactor. Thus,

there was no ammonia oxidation during this period, no alkalinity

consumption by AOB, and consequently, the pH increased from

7.6 to 8.5, shifting the equilibrium of nitrogen species for free

ammonia formation, which also contributed to process inhibition.

In summary, with increasing TOC concentrations in the swinewastewater, the AOB are suppressed by heterotrophic bacteria,

resultingin the accumulationof ammonia in the reactor,increased

pH, FA formation and limited AOB activity and growth in the PN

reactor.

In the same context, depending on the equilibrium of the

system,FNAinhibitionmayalsooccur.Anthonisenetal.11 reported

that nitrification may be inhibited by FNA at concentrations

between 0.22 and 2.8 mg L1 . According to Fig. 4(b), FNA

concentrations remained below the inhibitory concentrations

throughout the experiment, except on day 249, when due

to operational problems, there was a decrease in pH from

7.6 to 7.0 and the equilibrium was shifted to FNA formation,

reaching a concentration of 0.216 mgHNO2

L1

. However,these concentrations were not sufficient to influence the partial

nitritation process or inhibit the AOB activity.

Thus, the results obtained in this study showed that FA and FNA

have a significant inhibitory effect on the metabolism of nitrifying

biomass, and their concentrations are directly related to good

conditions of reactor operation.

CONCLUSIONSThe PN reactor had a distinct advantage in maintaining the

coexistence of autotrophic and heterotrophic processes in the

same environment with lower oxygen consumption compared

with conventional processes. However, for swine wastewater, it


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is recommended to work with carbon loading rates less than 2

kgTOC m3 d1, because when high organic matter coexists with

ammonium, the AOB cannot compete with heterotrophicbacteria

and tend to be eliminated and the partial nitritation performance

will be suppressed. Also, the FA concentration contributes to

keeping AOB inhibited due to the pH increasing.

The partial nitritation process has been achieved working with

swine undiluted wastewater under conditions of HRT 24 h, 1.84

mgO2L1 (SD = 0.41) DO, loading rate of 1.14 gTOC L1 d1

and 0.91 gNH3-N L1 d1 for more than 100 consecutive days.

At the same time, the system proved to be an effective tool for

TOC and TSS removal, reaching 84.9% (SD = 9.3) and 83.1% (SD

= 0.1), respectively, at all times. This study conducted with real

swine wastewater enhanced the case for the application of partial

nitritation as a technology for high load nitrogen conversion, and

allows the possibility of connection with anammox reactors.

ACKNOWLEDGEMENTSThis work was supported by the National Council for Scientific and

Technological Development (CNPq).

REFERENCES1 Kunz A, Miele M and Steinmetz R, Advanced swine manure treatment

andutilization in Brazil. Bioresource Technol100:54855489 (2009).2 Mulder A, van de Graaf AA, Robertson LA and Kuenen JG, Anaerobic

ammonium oxidation discovered in a denitrifying fluidized bedreactor.FEMS Microbiol Ecol16:177184 (1995).

3 Fux C, Boehler M, Huber P, Brunner I and Siegrist H, Biologicaltreatment of ammonium-rich wastewater by partial nitritation andsubsequent anaerobic ammonium oxidation (anammox) in a pilotplant.J Biotechnol99:295306 (2002).

4 Strous M, Kuenen JG and Jetten MSM, Key physiology of anaerobicammonium oxidation.Appl Environ Microbiol65:32483250 (1999).

5 Jetten MSM,etal, Improved nitrogen removal by application of newnitrogen cycle bacteria.RevEnviron SciBiotechnol1:51 63 (2002).

6 Jetten MSM, Strous M, van de Pas-Schoonen KT, Schalk J, Udo vanDongen GJM, van de Graaf AA, etal, The anaerobic oxidation ofammonium.FEMS Microbiol Rev22:421437 (1999).

7 Tang CJ, Zheng P, Wang CH, Mahmood Q, Zhang JQ, Chen XG,etal,Performance of high-loaded ANAMMOX UASB reactors containinggranular sludge.WaterRes 45:135144 (2011).

8 Jetten MSM, Wagner M, Fuerst J, van Loosdrecht MCM, Kuenen Gand Strous M, Microbiology and application of the anaerobicammonium oxidation (anammox) process. Curr Opin Biotechnol12:283 288 (2001).

9 Yamamoto T, Takaki K, Koyama T and Furukawa K, Novel partialnitritation treatment for anaerobic digestion liquor of swinewastewater using swim-bed technology. J Biosci Bioeng102:497503 (2006).

10 Scheeren MB, Kunz A, Steinmetz RLR and Dressler VL, O processoANAMMOX como alternativa para tratamento deaguasresiduarias,contendo alta concentracao de nitrogenio. Rev Bras Eng AgrcAmbiental15:12891297 (2011).

11 Anthonisen AC, Loehr RC, Prakasam TBS and Srinath EG, Inhibition ofnitrification by ammoniaand nitrous acid.J Water Pollut Control Fed48:835 852 (1976).

12 Canziani R, Emondi V, Garavaglia M, Malpei F, Pasinetti E andButtiglieri G, Effect of oxygen concentration on biological

nitrification and microbial kinetics in a cross-flow membranebioreactor (MBR) and moving-bed biofilm reactor (MBBR) treatingold landfill leachate.J Membr Sci286:202212 (2006).

13 Ciudad G,Rubilar O, Munoz P,Chamy G,Vergara C andJeison D,Partialnitrification of high ammonia concentration wastewater as a partof a shortcut biological nitrogen removal process. Process Biochem40:17151719 (2005).

14 Hellinga C, Schellen AAJC, Mulder JW, van Loosdrecht MCM andHeijnen JJ,TheSHARONprocess:aninnovativemethodfornitrogen

removal from ammonium-rich waste water. Water Sci Technol37:135 142 (1998).15 Yoo H, Ann KH, Lee HJ, Lee KH, Kwak YJ and Song KG, Nitrogen

removal from synthetic wastewater by simultaneous nitrificationand denitrification (SND) via nitrite in an intermittently-aeratedreactor.WaterRes 33:145 154 (1999).

16 Vanotti MB and Szogi AA, Water quality improvements of wastewaterfromconfined animalfeedingoperationsafter advanced treatment.J Environ Qual37:86 96 (2008).

17 Molinuevo B, Garca MC,Karakashev D and Angelidaki I, Anammox forammonia removal from pig manure effluents: effect of organicmatter content on process performance. Bioresource Technol100:21712175 (2008).

18 Li Z, Ma Y, Hira D, Fujii T and Furukawa K, Factors affecting thetreatment of reject water by the anammox process. BioresourceTechnol102:57025708 (2011).

19 Tang CJ, Zheng P, Wang CH and Mahmood Q, Suppression of

anaerobic ammonium-oxidizers under high organic contentin high-rate Anammox UASB reactor. Bioresource Technol101:17621768 (2010).

20 Rouse JD, Yazaki D, Cheng Y, Koyama T and Furukawa K, Swim-bedtechnology as an innovative attached-growth processfor high-ratewastewater treatment.Jpn J Water Treat Biol40:115 124 (2004).

21 APHA, AWWA, and WPCF: Standard Method for the Examination ofWaterandWastewater, 19thed. American PublicHealth Association,Washington, DC (1995).

22 Van Dongen U, Jetten MSM and van Loosdrecht MCM, The SHARON-ANAMMOX process for treatment of ammonium rich wastewater.Water SciTechnol44:153 160 (2001).

23 Munz G, Lubello C and Oleszkiewicz JA, Modeling the decay ofammonium oxidizing bacteria.WaterRes 45:557564 (2011).

24 Sinha B and Annachhatre AP, Partial nitrification operationalparametersand microorganisms involved. RevEnvironSciBiotechnol

6:285313 (2007).25 Wiesmann U, Biological nitrogen removal from wastewater, inAdvances in Biochemical Engineering Biotechnology, ed. byFiechter A. Springer-Verlag, Berlin/Heidelberg, pp. 113 154 (1994).

26 Yamamoto T, Wakamatsu S, Qiao S, Hira D, Fujii T and Furukawa K,Partial nitritation and anammox of a livestock manure digesterliquor and analysis of its microbial community.Bioresource Technol102:23422347 (2011).

27 Jianlong W and Ning Y, Partial nitrification under limited dissolvedoxygen conditions.Process Biochem 39:12231229 (2004).

28 Chung J, Shim H, Lee YW and Bae W, Comparison of influence of freeammonia and dissolved oxygen on nitrite accumulation betweensuspended and attached cells.Environ Technol26:21 33 (2005).

29 Zhang L, Yang J, Hira D, Fujii T and Furukawa K, High-rate partialnitrification treatment of reject water as a pretreatment foranaerobic ammonium oxidation (anammox). Bioresource Technol102:37613767 (2011).

30 Metcalf and Eddy ,Wastewater Engineering: Treatment and Reuse, 4thedn, McGraw Hill, New York, 1819 (2003).

31 Park S and Bae W, Modeling kinetics of ammonium oxidation andnitrite oxidation under simultaneous inhibition by free ammoniaand free nitrous acid.Process Biochem 44:631640 (2009).


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