EE05854B1

EE05854B1 - A method for removing nitrogen and phosphorus from wastewater using segregated activated sludge communities in a multi-stage biorefinery

Info

Publication number: EE05854B1
Application number: EEP201900030A
Authority: EE
Inventors: Olev Sokk; Enn Loigu; Karin Pachel; Argo Kuusik
Original assignee: Tallinna Tehnikaülikool
Priority date: 2019-12-19
Filing date: 2019-12-19
Publication date: 2023-05-15
Also published as: EE201900030A

Abstract

The invention relates to a method of removal of nitrogen and phosphor from waste water by means of segregated activated sludge in three stage biological treatment plant, according to which in the first stage the incoming waste water 1 is merged with active sludge sediment 26 of the third sedimentation basin, the outcoming mix 6 is directed into the first intermediate sedimentation basin 7 from where clarified water 8 from the first sedimentation basin is led through the second stage oxic zone 9 into second sedimentation basin 11 where it is separated into active sludge sediment 15 of the second sedimentation basin and clarified water 14 of the second sedimentation basin, whereas active sludge sediment 15 of the second sedimentation basin is led back to the oxic zone 9 of the second stage. In both stages segregated activated sludge is used and nitrates containing clarified water 14 from the second sedimentation basin 11 is directed back into anoxic zone 5 of the first stage where denitrification and conversion of adenosine diphosphate into adenosine triphosphate takes place, and which are entirely finished in the third stage anoxic zone 20 and oxic zone 22.

Description

MEETOD REOVEEST LÄMMASTIKU JA FOSFORI ÄRASTAMISEKS METHOD FOR REMOVING NITROGEN AND PHOSPHORUS FROM WASTEWATER

SEGREGEERITUD AKTIIVMUDA KOOSLUSTE ABIL MITMEASTMELISES BIOPUHASTIS SEGREGATED ACTIVATED SLUDGE IN A MULTISTAGE BIOTREATMENT PLANT WITH THE HELP OF COLLECTIONS

Tehnikavaldkond Technical field

Leiutis kuulub reoveepuhastuse valdkonda ja käsitleb meetodit reoveest lämmastiku ja fosfori tõhustatud ärastamiseks segregeeritud aktiivmuda koosluste abil mitmeastmelises biopuhastis, sealhulgas lämmastiku ärastamist ka madalatel temperatuuridel. The invention belongs to the field of wastewater treatment and relates to a method for enhanced removal of nitrogen and phosphorus from wastewater using segregated activated sludge communities in a multi-stage biological treatment plant, including nitrogen removal also at low temperatures.

Tehnika tase State of the art

Tuntud on leiutis (US5667688A), mis käsitleb meetodit reovee puhastamiseks kaheastmelise aktiivmudakoosluse abil, kus teise astme muda juhitakse teise astme setitist esimese astme torujuhtmesse, mis suubub esimese astme setitisse (ei ole näidatud). Seega on tegemist osaliselt segregeeritud mudadega, teises astmes on täielikult segregeeritud muda ning esimeses astmes on mõlema astme segu, mis vähendab esimese astme aktiivsust võrrelduna sellega, kui seal oleks ka täielikult segregeeritud muda. There is a known invention (US5667688A) which relates to a method for treating wastewater using a two-stage activated sludge system, where the second-stage sludge is fed from the second-stage sediment into a first-stage pipeline which flows into the first-stage sediment (not shown). Thus, the sludge is partially segregated, the second stage contains fully segregated sludge, and the first stage contains a mixture of both stages, which reduces the activity of the first stage compared to if there were also fully segregated sludge.

Tuntud on leiutis (EE05770B1), mis käsitleb meetodit reoveest lämmastiku ja fosfori ärastamist segregeeritud aktiivmuda koosluste abil kaheastmelises biopuhastis, mille kohaselt esimeses astmes viiakse sisenev reovesi kokku aktiivmudasettega, väljuv segu suunatakse vahesetitisse, millest reostust sisaldav selitatud vesi viiakse teises astmes läbi oksilise tsooni lõppsetitisse, milles see separeeritakse aktiivmudasetteks ja selitatud veeks, kusjuures aktiivmudasete juhitakse tagasi oksilisse tsooni. Kummaski astmes kasutatakse segregeeritud aktiivmudasid ja nitraate sisaldav selitatud vesi suunatakse lõppsetitist tagasi anoksilisse tsooni, kus viiakse läbi adenosiindifosfaadi konversioon adenosiintrifosfaadiks. Selle lahenduse puuduseks on, et anoksilise tsooni aereeritavasse ja mitteaereeritavasse tsooni (kummassegi) on paigaldatud oksüdatsioonredoks-potentsiaali (ORP) ja hapnikumõõturi andurid, mille vahendusel saadud näitude varal on võimalik otsustada, kas ja millisel määral juhtida sisenevat vett esimesest astmest mööda ja kas rakendada täiendavat aeratsiooni anoksilises tsoonis. Ekspluatatsioonis on selgunud, et nimetatud näitudest on vägagi keerukas juhinduda, sest koormused ja sellega seotud näidud muutuvad küllalt tihti ning puudub info, mil määral on taastunud esimese astme aktiivmudasettes (tagastusmudas) ATP (adenosiintrifosfaadi) tase. An invention (EE05770B1) is known, which relates to a method for removing nitrogen and phosphorus from wastewater using segregated activated sludge complexes in a two-stage biological treatment plant, according to which in the first stage the incoming wastewater is combined with activated sludge sediment, the outgoing mixture is directed to an intermediate settling tank, from which the clarified water containing pollution is directed in the second stage through an oxic zone to a final settling tank, in which it is separated into activated sludge sediment and clarified water, whereby the activated sludge sediment is directed back to the oxic zone. In both stages, segregated activated sludge is used, and the clarified water containing nitrates is directed back from the final settling tank to the anoxic zone, where the conversion of adenosine diphosphate to adenosine triphosphate is carried out. The disadvantage of this solution is that oxidation redox potential (ORP) and oxygen meter sensors are installed in the aerated and non-aerated zones of the anoxic zone (both), the readings of which make it possible to decide whether and to what extent to divert the incoming water past the first stage and whether to apply additional aeration in the anoxic zone. In operation, it has become clear that it is very difficult to follow these readings, because the loads and related readings change quite often and there is no information on the extent to which the ATP (adenosine triphosphate) level has recovered in the first stage activated sludge (return sludge).

Leiutisele kõige lähedasem tehnilise olemuse poolest on meetod (P201900018), mille kasutamisel aereeritakse täiendavalt esimese astme tagastusmuda diferentseeritud aeratsiooniseadmes, mille tulemusena muutuvad tagastusmuda koosseisus esinevad võimalikud ADP-jäägid ATP-ks ning seega realiseerub ATP regenereerumine palju täielikumalt, kuid see ei pruugi garanteerida 100% ATP-saagist, sest osa fosforit võib väljuda sellest astmest vahesetiti väljavoolu järgi ning selle sidumine teise astme mudasse jääb määratlematuks. Samuti võib jääda üsna juhuslikuks lämmastiku ärastus, sest selitatud vee retsirkulatsioonide astet ei saa tõsta lõpmatuseni ning arvutuslikult voolab osa vett puhastist läbi ilma denitrifikatsiooni läbimata. The closest to the invention in terms of technical nature is the method (P201900018), which uses additional aeration of the first-stage return sludge in a differentiated aeration device, as a result of which any ADP residues present in the return sludge are converted into ATP and thus ATP regeneration is realized much more completely, but this may not guarantee 100% ATP yield, because some phosphorus may exit this stage according to the outflow of the intermediate sediment and its binding to the second-stage sludge remains undefined. Nitrogen removal may also remain quite random, because the degree of clarified water recirculation cannot be increased to infinity and, by calculation, some water flows through the treatment plant without undergoing denitrification.

Leiutise olemus The essence of the invention

Esitatud leiutise eesmärgiks on viia lõpule ADP konversioon ATP-ks ja jääknitraatide ärakasutamine täiendavaks denitrifikatsiooniks, kasutada kõikides astmetes BHT-materjali ehk biokeemiliselt lagunduva orgaanilise aine degradatsiooni, mille tulemusena tekib heitvesi, millest on kõrvaldatud BHT materjal, lämmastik ja fosfor. The purpose of the presented invention is to complete the conversion of ADP to ATP and the utilization of residual nitrates for additional denitrification, to utilize the degradation of BOD material, i.e. biochemically degradable organic matter, in all stages, resulting in wastewater from which BOD material, nitrogen and phosphorus have been removed.

Leiutise sisuks on meetod reoveest lämmastiku ja fosfori ärastamiseks segregeeritud aktiivmuda koosluste abil diferentseeritud aeratsiooniga mitmeastmelises biopuhastis, milles on lisaks kolmas aste reoveest lämmastiku ja fosfori ärastamiseks. Meetodi kohaselt viiakse sisenev reovesi 1 kokku esimese astme anaeroobses tsoonis 3 lõppsetitist 24 tuleva lõppsetiti aktiivmudasettega 26. Esimese astme anaeroobsest tsoonist 3 viiakse segu anoksilise tsooni sissevoolu 4 kaudu esimese astme anoksilisse tsooni 5, kus segu segatakse teisest vahesetitist 11 võetud teises vahesetitis selitatud veega 14. Saadud segu suunatakse esimesse vahesetitisse 7, kus separeeritakse esimese vahesetiti selitatud vesi 8 ja esimese vahesetiti aktiivmudasete 19. Esimese vahesetiti selitatud vesi 8 suunatakse teise astme aeroobsesse tsooni 9 ja teise astme aeroobsest tsoonist väljuv aktiivmudasegu 10 suunatakse teise vahesetitisse 11, kust teise vahesetiti selitatud vee väljavoolu 17 ja esimese vahesetiti 7 esimese vahesetiti aktiivmudasete 19 suunatakse biopuhasti kolmanda astme anoksilisse tsooni 20 ja sealt kolmanda astme aeroobsesse tsooni 22 ja lõppsetitisse 24. Teises vahesetitis 11 separeeritakse teises vahesetitis selitatud vesi 14 ja teise vahesetiti aktiivmudasete 15, kusjuures teises vahesetitis selitatud vesi 14 suunatakse tagasi esimese astme anoksilisse tsooni 5 ja teise vahesetiti selitatud vee väljavool 17 viiakse kolmandasse The invention relates to a method for removing nitrogen and phosphorus from wastewater using segregated activated sludge communities in a multi-stage biological treatment plant with differentiated aeration, which additionally has a third stage for removing nitrogen and phosphorus from wastewater. According to the method, the incoming wastewater 1 is combined with the final sedimentation activated sludge 26 from the final sedimentation 24 in the first stage anaerobic zone 3. From the first stage anaerobic zone 3, the mixture is transferred through the anoxic zone inlet 4 to the first stage anoxic zone 5, where the mixture is mixed with the water clarified in the second intermediate sedimentation 14 taken from the second intermediate sedimentation 11. The resulting mixture is directed to the first intermediate sedimentation 7, where the clarified water 8 from the first intermediate sedimentation and the activated sludge sediment 19 from the first intermediate sedimentation are separated. The clarified water 8 from the first intermediate sedimentation is directed to the second stage aerobic zone 9 and the activated sludge mixture 10 leaving the second intermediate sedimentation zone is directed to the second intermediate sedimentation 11, from where the effluent 17 of the clarified water from the second intermediate sedimentation and the activated sludge sediment 19 from the first intermediate sedimentation 7 are directed to the third stage anoxic zone 20 of the biological treatment plant and from there to the third stage aerobic zone 22 and to the final settling tank 24. In the second intermediate settling tank 11, the water clarified in the second intermediate settling tank 14 and the activated sludge sediment 15 of the second intermediate settling tank are separated, whereby the water clarified in the second intermediate settling tank 14 is directed back to the anoxic zone 5 of the first stage and the outflow of the clarified water 17 of the second intermediate settling tank is directed to the third

astmesse ja teise vahesetiti aktiivmudasete 15 suunatakse tagasi teise astme aeroobsesse tsooni 9. stage and the activated sludge sediment 15 from the second intermediate stage is directed back to the aerobic zone 9 of the second stage.

Meetodi teises teostuses suunatakse sisenev reovesi 1 esimese astme anaeroobsesse tsooni 3, millest lähtuv anoksilise tsooni sissevool 4 viiakse kokku lõppsetitist 24 väljuva lõppsetiti aktiivmudasettega 26 ja suunatakse esimese astme anoksilisse tsooni 5 ning aktiivmudasegu tsirkulatsioon 18 esimese astme anoksilise tsooni 5 väljavoolust suunatakse tagasi esimese astme anaeroobsesse tsooni 3. In the second embodiment of the method, the incoming wastewater 1 is directed to the first-stage anaerobic zone 3, from which the anoxic zone inflow 4 is combined with the final sedimentation activated sludge 26 leaving the final sedimentation tank 24 and directed to the first-stage anoxic zone 5, and the activated sludge mixture circulation 18 from the outflow of the first-stage anoxic zone 5 is directed back to the first-stage anaerobic zone 3.

Biopuhasti esimeses ja kolmandas astmes kasutatakse ühte tüüpi segregeeritud aktiivmuda, millel on ühe- ja samatüübiline päritolu ning see on seotud toitainete N ja P kõrvaldamisega. Biopuhasti teises astmes kasutatakse teist tüüpi segregeeritud aktiivmuda, mis on seotud BHT kõrvaldamise ja ammoniakaalse lämmastiku nitrifikatsiooniga. Nitraatse lämmastiku kõrvaldamine viiakse lõpule kolmanda astme anoksilises tsoonis 20. The first and third stages of the biological treatment plant use one type of segregated activated sludge, which has the same origin and is involved in the removal of nutrients N and P. The second stage of the biological treatment plant uses another type of segregated activated sludge, which is involved in the removal of BOD and the nitrification of ammoniacal nitrogen. The removal of nitrate nitrogen is completed in the anoxic zone 20 of the third stage.

Jääk-adenosiindifosfaadi konversioon adenosiintrifosfaadiks viiakse lõpule kolmanda astme aeroobses tsoonis 22. The conversion of residual adenosine diphosphate to adenosine triphosphate is completed in the tertiary aerobic zone 22.

Segregeeritud aktiivmudade vanused ja kontsentratsioonid ning bakteriaalsed kooslused on erinevad ja segregeeritud aktiivmudadel on erinevad funktsioonid ning neil puudub omavaheline kontakt. The ages and concentrations and bacterial communities of the segregated activated sludge are different, and the segregated activated sludge has different functions and no contact with each other.

Jooniste loetelu List of drawings

Joonisel fig 1 on kujutatud meetodi teostamise tehnoloogiline skeem, kus taastunud aktiivmuda suunatakse lõppsetitist otse anaeroobsesse tsooni. Figure 1 shows a technological scheme for implementing the method, where the recovered activated sludge is directed from the final settler directly to the anaerobic zone.

Joonisel fig 2 on kujutatud meetodi teostamise tehnoloogiline skeem, kus taastunud aktiivmuda suunatakse lõppsetitist anaeroobsesse tsooni läbi esimese anoksilise tsooni. Figure 2 shows a technological scheme for carrying out the method, where the recovered activated sludge is directed from the final sedimentation tank to the anaerobic zone through the first anoxic zone.

Leiutise teostamise näide Example of carrying out the invention

Esitatud meetod sisaldab järgmisi toiminguid: meetodi ühes teostuses viiakse sisenev reovesi 1 kokku esimese astme anaeroobses tsoonis 3 lõppsetitist 24 tuleva lõppsetiti aktiivmudasettega 26 (otsene mudatsirkulatsioon). Reovesi 1 on soovitavalt läbinud võre ja liivapüünise (ei ole näidatud) ning olenevalt reovee iseloomust võib ta olla või mitte olla läbinud eelsetiti (ei ole näidatud). Esimese astme anaeroobset tsooni 3 ei õhustata, aktiivmuda hõljuvas olekus hoidmiseks on paigaldatud sinna The presented method comprises the following steps: in one embodiment of the method, the incoming wastewater 1 is brought into contact with the final sludge sludge 26 (direct sludge circulation) from the final clarifier 24 in the first stage anaerobic zone 3 (direct sludge circulation). The wastewater 1 has preferably passed through a screen and a sand trap (not shown) and, depending on the nature of the wastewater, may or may not have passed through a pre-clarifier (not shown). The first stage anaerobic zone 3 is not aerated, and a

segistid (ei ole näidatud). Esimese astme anaeroobsest tsoonist 3 pärinev segu liigub anoksilise tsooni sissevoolu 4 kaudu esimese astme anoksilisse tsooni 5. Esimese astme anoksilises tsoonis 5 toimub segunemine teisest vahesetistist 11 võetud teises vahesetitis selitatud veega 14, mis sisaldab nitraate ja selles praktiliselt puudub aeroobsest tsoonist pärit aktiivmuda ja BHT aines, kuid olenevalt mitmesuguste tingimuste kombineerumisest on nimetatud komponentide väiksem sisaldus põhimõtteliselt võimalik. See vesi, olenevalt tehnoloogilisest lahendist, võetakse teisest vahesetitist 11, kas teise vahesetiti pinnalt lähtuvast selitatud veest 12 või teise vahesetiti selitatud väljavoolust lähtuvast selitatud veest 13. Esimese astme anoksilisest tsoonist 5 väljavoolava segu 6 koostises sisalduv sisenenud reovesi 1 on BHT osas osaliselt puhastunud ning väljavoolav segu 6, mis on ATP osas osaliselt taastunud ja nitraatidest eeldatavalt vabastatud, suunatakse esimesse vahesetitisse 7, mille aktiivmudasete 19 suunatakse kolmanda astme anoksilisse tsooni 20, mis on varustatud segistiga ja mida ei aereerita. mixers (not shown). The mixture from the first stage anaerobic zone 3 moves through the inflow 4 of the anoxic zone to the first stage anoxic zone 5. In the first stage anoxic zone 5, mixing takes place with the water 14 clarified in the second intermediate settling tank taken from the second intermediate settling tank 11, which contains nitrates and is practically free of activated sludge and BOD from the aerobic zone, but depending on the combination of various conditions, a lower content of these components is in principle possible. This water, depending on the technological solution, is taken from the second intermediate clarifier 11, either from the clarified water 12 coming from the surface of the second intermediate clarifier or from the clarified water 13 coming from the clarified outflow of the second intermediate clarifier. The incoming wastewater 1 contained in the composition of the mixture 6 flowing out of the first-stage anoxic zone 5 is partially purified in terms of BOD, and the flowing mixture 6, which is partially recovered in terms of ATP and presumably freed from nitrates, is directed to the first intermediate clarifier 7, the activated sludge sediments 19 of which are directed to the third-stage anoxic zone 20, which is equipped with a mixer and is not aerated.

Esimeses vahesetitis 7 saadud esimese vahesetiti selitatud vesi 8 (sisaldab jääk BHT-d) suunatakse teise astme aeroobsesse tsooni 9 ja sealt edasi teise vahesetitisse 11, kust teise vahesetiti aktiivmudasete 15 tsirkuleerib aktiivmuda tagastusena teise astme aeroobsesse tsooni 9 ja toimub liigse aktiivmuda ärastamine 16teisest vahesetitist. The clarified water 8 (containing residual BOD) obtained from the first intermediate settler 7 is directed to the second stage aerobic zone 9 and from there to the second intermediate settler 11, from where the activated sludge sediment 15 of the second intermediate settler circulates as activated sludge return to the second stage aerobic zone 9 and excess activated sludge is removed 16 from the second intermediate settler.

Teises vahesetitis 11 jaguneb selitatud vesi, mis sisaldab nitraate, kaheks - teise vahesetiti selitatud veeks 14 ja vee väljavooluks 17. Neist teise vahesetiti selitatud vesi 14 suunatakse pinnalt lähtuva selitatud vee 12 ja/või väljavoolust lähtuva selitatud vee 13 abil esimese astme anoksilisse tsooni 5 ja see on mahuliselt suurem. Teise vahesetiti selitatud vee väljavool 17 on koguseliselt praktiliselt võrdne siseneva reovee 1 vooluga ja ta suundub kolmanda astme anoksilisse tsooni 20, kuhu suundub ka esimese vahesetiti 7 aktiivmudasete 19. Kolmanda astme anoksiline tsoon 20 on varustatud segistiga ja seda ei aereerita. Kolmanda astme anoksilises tsoonis 20 viiakse lõpuni hapnikku sisaldavate nitritite-nitraatide degradatsioon. Kolmanda astme anoksilisest tsoonist 20 lähtuv kolmanda astme anoksilise tsooni väljavool 21 juhitakse kolmanda astme aeroobsesse tsooni 22. Selles tsoonis viiakse lõpuni ADP muundumine ATP-ks ja see aereeritav segu lahkub kolmanda astme väljavoolu 23 kaudu lõppsetitisse 24, kus eraldub aktiivmudasete, mis jaguneb lõppsetiti aktiivmudasetteks 26 ja fosforirikkaks liigse aktiivmuda In the second intermediate settler 11, the clarified water containing nitrates is divided into two - the clarified water of the second intermediate settler 14 and the water outflow 17. The clarified water of the second intermediate settler 14 is directed to the first-stage anoxic zone 5 by means of the clarified water 12 coming from the surface and/or the clarified water 13 coming from the outflow and is larger in volume. The clarified water outflow 17 of the second intermediate settler is practically equal in quantity to the flow of the incoming wastewater 1 and is directed to the third-stage anoxic zone 20, where the activated sludge 19 of the first intermediate settler 7 also goes. The third-stage anoxic zone 20 is equipped with a mixer and is not aerated. In the third-stage anoxic zone 20, the degradation of oxygen-containing nitrites-nitrates is completed. The tertiary anoxic zone effluent 21 from the tertiary anoxic zone 20 is directed to the tertiary aerobic zone 22. In this zone, the conversion of ADP to ATP is completed and this aerated mixture leaves the tertiary effluent 23 to the final settler 24, where the activated sludge is separated, which is divided into the final settler activated sludge 26 and the phosphorus-rich excess activated sludge.

ärastuseks 27 lõppsetitist. Heitvesi 25 on selitatud vesi, mis on täielikult vabastatud fosforist ja lämmastikust ning normatiivselt heljumist ja BHT-st. 27 final sedimentation tanks are used for the discharge. 25 of the effluents are clarified water, which is completely free of phosphorus and nitrogen and, according to the standard, suspended solids and BOD.

Lõppsetiti aktiivmudasete 26 suunatakse normaalsete olude korral (meetodi esimeses teostuses) tagasi esimese astme anaeroobsesse tsooni 3 (otsene aktiivmuda tagastus, joonis fig 1) või kui anaeroobne protsess saab seeläbi häiritud (meetodi teises teostuses), siis esimese astme anoksilise tsooni 5 kaudu aktiivmudasegu tsirkulatsiooniga 18 (vahendatud aktiivmuda-tagastus) esimese astme anaeroobsesse tsooni 3 (joonis fig 2). The activated sludge sediment 26 of the final septic tank is directed under normal conditions (in the first embodiment of the method) back to the first-stage anaerobic zone 3 (direct activated sludge return, Figure 1) or, if the anaerobic process is thereby disturbed (in the second embodiment of the method), then through the first-stage anoxic zone 5 with the activated sludge mixture circulation 18 (mediated activated sludge return) to the first-stage anaerobic zone 3 (Figure 2).

Veel parema tulemuse saavutamiseks võib kaskaadi lülitada tagasipesuga liivafiltri (ei ole näidatud). For even better results, the cascade can be connected to a backwash sand filter (not shown).

Leiutisekohast meetodit realiseeriv seade on kolmeastmeline biopuhasti, kus esimese astme moodustavad esimese astme anaeroobne tsoon 3, esimese astme anoksiline tsoon 5 ja esimene vahesetiti 7. Teiseks astmeks on teise astme aeroobne tsoon 9 ja sellele järgnev teine vahesetiti 11. Kolmanda astme moodustavad kolmanda astme anoksiline tsoon 20, kolmanda astme aeroobne tsoon 22 ja lõppsetiti 24. The device implementing the method according to the invention is a three-stage biological treatment plant, where the first stage consists of the first stage anaerobic zone 3, the first stage anoxic zone 5 and the first intermediate settler 7. The second stage consists of the second stage aerobic zone 9 and the second intermediate settler 11 following it. The third stage consists of the third stage anoxic zone 20, the third stage aerobic zone 22 and the final settler 24.

Viitenumbrite loetelu List of reference numbers

1 reovesi 1 wastewater

2 osaline möödavool 2-way bypass

3 esimese astme anaeroobne tsoon 3 first stage anaerobic zone

4 anoksilise tsooni sissevool 4 anoxic zone inflow

5 esimese astme anoksiline tsoon 5 first-stage anoxic zone

6 väljavoolav segu 6 flowing mixture

7 esimene vahesetiti 7 first intermediate set

8 esimese vahesetiti selitatud vesi 8 first intermediate sediment clarified water

9 teise astme aeroobne tsoon 9 second level aerobic zone

10 teise astme aeroobsest tsoonist väljuv aktiivmudasegu 11 teine vahesetiti 10 activated sludge mixture leaving the second stage aerobic zone 11 second intermediate settling tank

12 teise vahesetiti pinnalt lähtuv selitatud vesi 12 clarified water from the surface of the second intermediate sediment

13 teise vahesetiti väljavoolust lähtuv selitatud vesi 13 clarified water from the outflow of the second intermediate settling tank

14 teises vahesetitis selitatud vesi 14 clarified water in the second intermediate stage

15 teise vahesetiti aktiivmudasete 15 second intermediate activated sludge sediments

16 liigse aktiivmuda ärastus teisest vahesetitist 16 removal of excess activated sludge from the second intermediate clarifier

17 teise vahesetiti selitatud vee väljavool 17 second intermediate settling tank clarified water outflow

18 aktiivmudasegu tsirkulatsioon 18 activated sludge circulation

19 esimese vahesetiti aktiivmudasete 19 activated sludge deposits of the first intermediate set

20 kolmanda astme anoksiline tsoon 20 tertiary anoxic zone

21 kolmanda astme anoksilise tsooni väljavool 21 tertiary anoxic zone outflow

22 kolmanda astme aeroobne tsoon 22 tertiary aerobic zone

23 kolmanda astme väljavool 23 tertiary outflow

24 lõppsetiti 24 final sets

25 heitvesi 25 wastewater

26 lõppsetiti aktiivmudasete 26 final activated sludge sediments

27 liigse aktiivmuda ärastus lõppsetitist 27 Removal of excess activated sludge from the final settler

Claims

1. A method for removing nitrogen and phosphorus from wastewater using segregated activated sludge communities in a multi-stage biological treatment plant, according to which the incoming wastewater (1) is directed to the first stage anaerobic zone (3) or the first stage anoxic zone (5), the mixture (6) flowing out of the first stage anoxic zone (5) is directed to the first intermediate settling tank (7), the clarified water (8) from the first intermediate settling tank is directed to the second stage aerobic zone (9) and from there to the second intermediate settling tank (11), in the second intermediate settling tank (11) the clarified water (14) from the second intermediate settling tank and the activated sludge sediment (15) from the second intermediate settling tank are separated, whereby the clarified water (14) from the second intermediate settling tank is directed back to the first stage anoxic zone (5) and the activated sludge sediment (15) from the second intermediate settling tank is directed back to the second stage aerobic zone (9), characterized in that - the mixture of the clarified water outflow (17) from the second intermediate settling tank and the activated sludge sediment (19) from the first intermediate settling tank is directed to the third stage anoxic zone (20) and from there to the third stage aerobic zone (22) and the final settler (24); - in the final settler (24), the final settler activated sludge sediment (26) and the wastewater (25) are separated, whereby the final settler activated sludge sediment (26) is directed back to the first stage anaerobic zone (3) or the first stage anoxic zone (5); - one type of segregated activated sludge is used in the first and third stages and another type of segregated activated sludge is used in the second stage.

2. The method according to claim 1, characterized in that the incoming wastewater (1) is directed to the first-stage anaerobic zone (3), from which the inflow (4) of the anoxic zone is combined with the activated sludge sediment (26) of the final sedimentation tank (24) and directed to the first-stage anoxic zone (5), and the circulation (18) of the activated sludge mixture from the outflow of the first-stage anoxic zone (5) is directed back to the first-stage anaerobic zone (3).

3. The method according to claim 1, characterized in that the activated sludges segregated in the first and third stages have the same origin and type and are related to the removal of nutrients N and P.

4. The method according to claim 1, characterized in that the second stage segregated activated sludge is associated with BOD removal and ammoniacal nitrogen nitrification.

5. The method of claim 1, wherein the conversion of residual adenosine diphosphate to adenosine triphosphate is completed in the tertiary aerobic zone (22).

6. The method of claim 1, wherein the removal of nitrate nitrogen is completed in a tertiary anoxic zone (20).

7. The method according to claim 1, characterized in that the segregated activated sludges have different functions and are not in contact with each other.