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Combined ae a ion and mixing sys em and i s use in p ac ice
To ci e his a icle: V Sing o a and J Se cik 2020 IOP Con . Se .: Ea h En i on. Sci. 444 012049
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Ad ances in En i onmen al Enginee ing
IOP Con . Se ies: Ea h and En i onmen al Science 444 (2020) 012049
IOP Publishing
doi:10.1088/1755-1315/444/1/012049
1
Combined ae a ion and mixing sys em and i s use in p ac ice
V Sing o a
1
and J Se cik
1
1
Ins i u e o municipal wa e managemen , B no Uni e si y o Technology, Facul y o
Ci il Enginee ing, Zizko a 17, 602 00 B no, Czech Republic
Abs ac . The a icle deals wi h combined sys ems, which a e mainly used in was ewa e
ea men plan s o he pu pose o ae a ion and mixing. These sys ems a e mainly ins alled in
ac i a ion eac o s, bu hei use is also possible, o example, in sludge s o age anks. The
combined sys ems a e capable o gua an eeing he equi ed alues o ele an moni o ed
pollu ion indica o s a he WWTP e luen . The aim o his a icle is o desc ibe he ac i a ion
eac o con ol algo i hm wi h he combined sys em. Reliable unc ionali y is p o ed by he
p esen ed a e age alues a he WTP e luen , which mee he equi ed emission limi s se by
ele an pe mi s.
1. In oduc ion
The basic cha ac e is ic and ad an age o he combined sys ems is ha hey p o ide mixing and
ae a ion unc ions. The combined sys ems may use di e en ypes o ae a ion depending on hei use,
loca ion and cha ac e is ics.
Subme sible combined sys ems a e usually ins alled a he bo om o he eac o in i s cen e and a e
comple ely subme ged. Mo o s and ai pipes a e excep ions ha usually un o e he le el o a e
connec ed o blowe s. Fo example, some o hem a e capable o eeding a mix u e o was ewa e
and ai in o o he eac o in a adial di ec ion. O he s may ha e a hype boloid shape, which suppo s
lowing in he eac o .
Su ace- ype combined sys ems a e ins alled on ixed b idges o loa s. Floa s enable mo emen
depending on he wa e le el. A pa o he sys em is always in con ac wi h wa e and ano he pa is
abo e he wa e le el. These may be, o example, paddle ae a o s o u bines. Sys ems using ai
en ainmen o suc ion om he ambien en i onmen .
2. Ai e O
2
T i on sys em
Equipmen abo e he wa e le el sucks ai which is ed h ough a hollow sha i he ou le wi h a
di use ensu ing i s dispe sion Mixing is ensu ed by special paddles. The bubble pa h is hus di e en
om con en ional ae a ion sys ems (see Figu e 1 and Figu e 2) [2]. No mally, T i on is ixed by a
i m b acke o loa s a he sides o in he cen e o he eac o .
The Ai e O
2
T i on sys em is used in was ewa e ea men anks in ae a ion eac o s bu i can also be
used in sludge hickening o s o age anks. The sys em is capable o ensu ing sepa a e mixing o
mixing and ae a ion.
The ideal eac o shape o his sys em is ci cula o o al (ci cula ion ac i a ion sys em). Such eac o s
make he bes o his sys em po en ial [1]. In ec angula eac o s he e may be a p oblem wi h
su icien homogeniza ion o he en i e olume and sludge se ling in dead a eas. Fo hese easons, i
is possible o i he sys ems ins alled in such eac o s wi h a gea box ha ensu es i s o a ion, which
elimina es his p oblem [2]. Ano he possibili y is o de elop a model and analyse wa e mo emen in
he eac o . This can help ind he ideal loca ion o he sys em ins alla ion.
Ad ances in En i onmen al Enginee ing
IOP Con . Se ies: Ea h and En i onmen al Science 444 (2020) 012049
IOP Publishing
doi:10.1088/1755-1315/444/1/012049
2
S anda d calcula ion o oxygena ion capaci y o pneuma ic ae a ion canno be ully elied upon o
hese sys ems. Ope a o s’ expe ience show ha T i on is able o handle loads o up o wice he
popula ion equi alen popula ion han as speci ied in his calcula ion [1].
Figu e 1. T i on sys em ae a ion p ocess [2]. Figu e 2. T i on sys em mixing p ocess [2].
2.1. O he sys em applica ions
In addi ion o WWTPs, he sys em is also commonly used o imp o e he quali y o su ace wa e , o
example in lakes o ponds. I can also be used o p e en om eezing in acili ies whe e he e is a
isk o undesi able eezing o he loa s e c. Fo hese easons, he sys em can only be en ed ou o
imp o e he cu en si ua ion. Acco ding o a ailable in o ma ion, he T i on sys em has been ins alled
a abou 37 WWTPs and six o he si es in he Czech Republic. In o al, i should be abou 118 T i ons
[2].
The sys em is pa en ed by Ae a ion Indus ies In e na ional, Inc. (Minneso a, USA) in se e al
modi ica ions. T i on is commonly used wo ldwide also o indus ial was ewa e ea men . These
applica ions include, o example, ea men o wa e om ood indus ial plan s, wine-g owing
companies, chemical and pe ochemical indus ies bu also om land ills e c. [3].
3. Ac i a ion eac o p ocess con ol
Ni i ica ion and deni i ica ion p ocess con ol can a y. Sui able op imiza ion can educe he cos o
elec ici y, educe equi emen s o he ope a o s and esul in a educed ni ogen ou le alues. The
inpu alues a e a iable o e ime, bo h he was ewa e composi ion and i s quan i y change [4].
Few measu emen s we e conduc ed in eal ime in he pas . In his espec , i was necessa y o ely on
he s a expe ience. Nowadays, he con ol is g ea ly acili a ed by au oma ion. I necessa y,
equipmen app o ed by he ope a o as necessa y and help ul can be au oma ed [5, 6]. In o ma ion on
he ope a ion i sel , he indi idual acili ies and pa ame e s is hus p o ided o he WWTP s a and he
ope a o . Acco ding o such in o ma ion, i is also possible o con ol he indi idual pieces o
equipmen emo ely o i can be con olled based on p e-se algo i hms.
Ac i a ion eac o p ocesses can be con olled by:
• ni i ica ion and deni i ica ion in e al se poin s,
• dissol ed oxygen concen a ion,
• ammonia ni ogen concen a ion
• ammonia ni ogen and ni a e concen a ion.
4. Use o he combined sys em in p ac ice
The in o ma ion and da a below was p o ided by VaK Hodonín, a.s. The selec ed WWTP is ully
au oma ed wi h N-NH
4+
and N-NO
3-
. The plan was designed o 600 PE [1].
Two Ai e O
2
T i on sys ems a e used as he ae a ion sys em. Mixe s a e also ins alled in he ac i a ion
eac o s. This measu e is mainly in oduced o sa e elec ici y. A p esen , a e consul a ion wi h he
manu ac u e a o he WWTPs, equency con e e s a e ins alled on he T i on sys ems.
Ad ances in En i onmen al Enginee ing
IOP Con . Se ies: Ea h and En i onmen al Science 444 (2020) 012049
IOP Publishing
doi:10.1088/1755-1315/444/1/012049
3
In ea men plan s, hys e esis is se and conside ed o measu e concen a ions in he ac i a ion
eac o s (which is ela ed o he subsequen swi ching on and o o indi idual pieces o equipmen ).
This p e en s om he sys em luc ua ions and he equipmen is no unnecessa ily o e loaded by
cons an swi ching on and o .
4.1. Ac i a ion eac o algo i hm desc ip ion
P ocesses in he ac i a ion eac o a e p ima ily con olled by ISE p obes (i.e. acco ding o he
concen a ions o ammonia ni ogen and ni a es). In case o ailu e o his p obe, i is con ol he
p ocesses by an OXI p obe. Bo h o hese algo i hms ope a e acco ding o he se poin i he pH o
was ewa e a he inle is wi hin he desi ed ange and he c i ical empe a u e o he mixed liquo has
no been exceeded.
4.1.1. pH con ol. This s ep p eceded all o he con ol algo i hms due o equen WWTP poisoning.
The plan is loca ed in a wine-g owing a ea and in he pas his caused conside able issues ega dless
o he cos s o inocula ion
I he p e-se pH limi s a e exceeded, an ala m ge s igge ed au oma ically. I he lowe limi is
exceeded, bo h ae a ion sys ems a e ac i a ed. When he pH e u ns o he equi ed limi s, his p ocess
is main ained o a ce ain pe iod o ime o sa e y easons and hen ollowed by a s anda d s a o
ni i ica ion.
4.1.2. Tempe a u e con ol. Oxygen solubili y d ops wi h a ising ac i a ion empe a u e. Fo his
eason, he demanded oxygen limi s a e shi ed. The e is an e o o achie e his alue e en i i is a
a he heo e ical limi . A d op by hal a deg ee below his c i ical empe a u e e u ns he sys em o
he s anda d con ol mode.
4.1.3. P ocess con ol based on he ISE p obe. No mally, he sys em is managed based on ammonia
ni ogen and ni a e alues. The sys em eac s o changes in he N-NH
4+
alue and ae a ion is
con olled acco dingly. A e he basic ime needed o he sys em ae a ion, he N-NH
4+
con en is
e alua ed based on an algo i hm. Ae a ion is hen comple ed, p olonged o p olonged wi h a s a up
o a second ae a ion sys em. An oxygen p obe con ibu es o checking he high N-NH
4+
concen a ion
alues and useless eac o ae a ion - ene gy poin o iew. Regula ion due o high N-NO
3-
occu s only
when N-NH
4+
is wi hin he se limi s.
4.1.4. P ocess con ol based on he OXI p obe. Du ing ni i ica ion, he sys em a emp s o each a
ce ain se limi o dissol ed oxygen concen a ion in he eac o . The equi ed oxygen limi a ies
depending on he empe a u e o he mixed liquo . A he same ime, howe e , he maximum and
minimum ni i ica ion pe iod is se .
Unde s anda d condi ions, one o he T i ons is in ope a ion. A he end o his basic pe iod, he
sys em begins o decide whe he o no he equi ed limi has been eached. Thus, his is ollowed by
p olonged ni i ica ion, e mina ed ae a ion o s a up o ano he T i on sys em. Once his limi has
been eached, he mixing ansi ion phase akes place o a ixed pe iod o ime o un il he dissol ed
oxygen concen a ion has d opped o he deni i ica ion limi . The du a ion o he deni i ica ion
p ocess is also ixed and can be ex ended.
4.2. Concen a ion p og ess - eal alues
Figu e 3 shows he concen a ions o measu ed pa ame e s in he ac i a ion eac o o e 24 hou s. This
a e alues ( om he bo om up) o dissol ed oxygen, ammonia ni ogen (N-NH
4+
) and ni a es (N-
NO
3-
). The ni a es g aph, espec i ely i s alues, a e ela ed o he igh axis.
The phases o ni i ica ion and deni i ica ion can be easily obse ed in he g aph. This esul s in he
deg ada ion o ammonia ni ogen accompanied by an inc ease in ni a es du ing ae a ion and a
dec ease in ni a e con en wi h a dec ease in dissol ed oxygen con en du ing he subsequen
deni i ica ion p ocess.
Ad ances in En i onmen al Enginee ing
IOP Con . Se ies: Ea h and En i onmen al Science 444 (2020) 012049
IOP Publishing
doi:10.1088/1755-1315/444/1/012049
4
Figu e 3. Concen a ion p og ess - measu ed pa ame e s o e 24 hou s.
5. WWTP e luen ope a ing alues
The ables below show he e luen alues o wo was ewa e ea men plan s ope a ed by one
ope a o . Bo h o hem use he T i on sys em in he ac i a ion eac o s. To unde s and he ea men
e iciency o hese sys ems, he ables show emission limi s and a e age alues o he moni o ed
indica o s o he whole yea .
Table 1. Emission limi s o discha ged was ewa e indica o s [1].
BOD
[mg·l
-1
]
COD
[mg·l
-1
]
SS
[mg·l
-1
]
N-NH
4+
[mg·l
-1
]
Value “p” (pe missible) 22 75 25 a e age 12
Value “m” (maximum) 30 140 30 20
Table 2. A e age alues o moni o ed indica o s o he calenda yea [1].
BOD
[mg·l
-1
]
COD
[mg·
l
-1
]
SS
[mg·l
-1
]
N-NH
4+
[mg·l
-1
]
WWTP “A” 3,11 28,93 6,30 0,14
WWTP “B” 3,08 24,93 8,08 1,87
Table 1 and Table 2 show ha he T i on sys em ensu es he equi ed WWTP e luen alues wi hou
any p oblems. This con i ms e y high e iciency o he en i e sys em. This expe ience, oge he wi h
o he indings, make he ope a o us he sys em, e en in ela ion o he u u e de elopmen o
municipali ies and owns. The e luen alues a e conside ably lowe han he limi alues p esc ibed
by he ele an municipal au ho i y.
0
10
20
30
40
50
60
0
1
2
3
4
5
6
7
8
9
10
10.0…
10.0…
10.0…
10.0…
10.0…
10.0…
10.0…
10.0…
10.0…
10.0…
10.0…
10.0…
10.0…
10.0…
10.0…
10.0…
10.0…
11.0…
11.0…
11.0…
11.0…
11.0…
11.0…
11.0…
11.0…
11.0…
11.0…
11.0…
11.0…
11.0…
11.0…
11.0…
11.0…
11.0…
11.0…
11.0…
N-NO3-
oxygen, N-NH4+
Kyslík [mg.l-1] N-NH4+ [mg.l-1] N-NO3- [mg.l-1]

Ad ances in En i onmen al Enginee ing
IOP Con . Se ies: Ea h and En i onmen al Science 444 (2020) 012049
IOP Publishing
doi:10.1088/1755-1315/444/1/012049
5
6. Conclusions
The e is qui e a high numbe o combined sys ems a ailable on he ma ke . Howe e , ope a o s o en
p e e con en ional blowe s and ae a ion elemen s. This is one o he easons why he e a e gaps in he
ope a ional expe ience wi h combined sys ems. The cou age associa ed wi h he deploymen o
combined sys ems, hei ope a ion and subsequen modi ica ions o con ol algo i hms is ce ainly
undeniable. The use o such sys ems helps u he esea ch, new ideas and inno a ions.
Pa ame e s en e ing he con ol algo i hm (i.e. all concen a ions, imes, empe a u es,…) need o be
es ed and adjus ed du ing he ial ope a ion. Each and e e y municipali y has i s speci ic composi ion
o was ewa e , a ying deg ees o ballas wa e , ega dless o any indus ial en e p ises. Fo hese and
o he easons, i is necessa y o app oach each WWTP and i s con ol indi idually, o moni o and
check he p ocesses. I is also c ucial o se a kind o sa e y elemen s when con olling he sys em.
How he sys em should e alua e eme gency si ua ions, a e wha pe iod and how o espond
accu a ely. The con ol is o cou se ela ed o he ans e o cu en in o ma ion and da a o he con ol
cen e.
In he u u e, hese sys ems should be explo ed om he ene gy poin o iew, in e ms o he
necessa y ai demand and unc ionali y o he ac i a ion p ocesses a low empe a u es. Fo he ime
being, he eliabili y o he ea men has been p o en using he alues o moni o ed indica o s o he
selec ed WWTP e luen s.
Acknowledgemen s
I would like o exp ess my hanks o VaK Hodonín, a.s. o he possibili y o publishing he da a and
o p o iding suppo ing da a and in o ma ion. I also e y much app ecia e he documen sha ing wi h
ZEMSKÝ Roha ec, s. .o, hei help ulness and communica ion.
The pape was d awn up wi hin he s anda d p ojec No. FAST-J-18-5545 “Tes ing o abso p ion
media o odou emo al om sewe s”.
Re e ences
[1] Documen s and in o ma ion p o ided by VaK Hodonín, a.s
[2] Documen and in o ma ion p o ided by ZEMSKÝ Roha ec, s. .o. A ailable on:
h ps://www.zemsky.cz/
[3] The Ai e-O
2
T i on TR Se ies Ae a o /Mixe , Ae a ion Indus ies In e na ional: a new e a
company [online]. [ci . 2019-10-10]. A aible on: h ps://www.ai eo2.com/en/home-page/
[4] Hluš ík P, Václa ík V and D o ský T 2016 Causes and impac s o d opping wa e consump ion
on a was ewa e ea men plan (Leiden: CRC P ess/Balkema) pp 419-424
[5] D o ský T, Václa ík V and Hluš ík P 2016 Was e wa e ea men in No h Mo a ia and
Silesia, om he pas o he p esen (Leiden: CRC P ess/Balkema) pp 389-394
[6] Hluš ík P and Sing o á V 2018 E iciency o was ewa e ea men plan s (Albena: STEF92
Technology) pp 321-28