Autotrophic nitrogen removal processes for nutrient removal from sidestream and mainstream wastewater
Date
2022-12-21
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Tekkivate jäätmekoguste suurenemine ohustab tänapäeval keskkonna kvaliteeti ja inimeste tervist. Reovee bioloogiline puhastus on energiasäästlik viis orgaaniliste ja anorgaaniliste saasteainete eemaldamiseks reoveest ning jääkainete põhjavette sattumise tõenäosuse vähendamiseks. Mitmete biogaasijaamade rakendamine hõlmab orgaanilise süsiniku muundamist biogaasiks ning kõrgenenud sisaldusega lämmastiku- ja fosforiühendite esinemist heitvees. Selliste jäätmevoogude töötlemine on kulukas traditsiooniliste meetoditega (nitrifikatsioon-denitrifikatsioon), mis nõuab orgaanilise süsiniku lisamist tagasi töötlemisprotsessi (sageli metanooli kujul). Reoveepuhastuse tehnoloogiate hulgas on anaeroobset ammooniumi oksüdatsiooni protsessi (anammox) kaasatud autotroofse lämmastiku eemaldamisse piloot- ja täismahus tehnoloogiates lämmastiku eemaldamiseks reoveest vähese orgaanilise süsiniku kasutamisega.
Peavoogu võib nimetada olmereoveeks ja kõrvalvoogu väduks, viimane tekib pärast liigmuda kääritamist ja tsentrifuugimist. Anammox protsessi on püütud kaasata nii kõrvalvoo kui ka peavoo puhastusse, kasutades liikuvate kandjatega biokilereaktorit (MBBR) ja annuspuhastuse reaktori (SBR) tehnoloogiaid.
Võrreldes kõrvalvoo puhastamisega, on peamised takistused, mis tuleb ületada, et saavutada edukas anammox protsessi kasutamine peavoos: reovee kõrge süsiniku ja lämmastiku suhe (C/N>1) ja reovee madal temperatuur (põhjamaade kliimas 12,5–19 °C). Varasemad uuringud peavoo anammox protsessi kasutamise kohta on näidanud, et madalad temperatuurid võivad tekitada probleeme anammox biomassi kasvule. Et ületada madalate temperatuuride pärssivat mõju anam-mox bakterite kasvukiirusele, saab peavoo süsteemi nakatada kõrvalvoolu tingimustes kasvatatava biomassiga.
Muutused redokspotentsiaalis (ORP-s) mõjutavad bakterite jaoks elutähtsate valkude koostist või mõjutavad bakterite mitokondriaalsete membraanide laengut. ORP muutusi saab juhtida aeratsiooni sisse/välja lülitamisega või aeraatoripõhiste intensiivsuse muutuste muutmisega, kasutades ORP-anduri signaali ja sobivate väärtuste vahemikke.
Reovee soolsus ja hüdrasiini mõju on olulised parameetrid, mille abil hinnata anammox protsessi kulgu. Optimaalse soolsuse taseme saavutamine suurendab anammox protsessi aktiivsust ja lämmastiku eemaldamise kiirust. Anammox protsessi vaheühend – hüdrasiin, võib mõjutada anammox protsessi efektiivsust, kuid kahandada ka muid protsesse, näiteks denitrifikatsiooni, et saavutada kõrge lämmastiku eemaldamine autotroofselt.
The increase in the amount of generated waste today threatens the quality of the environment and human health. Biological treatment of wastewater is an energy-efficient way to remove organic and inorganic pollutants from wastewater and to reduce the likelihood of residues entering the groundwater. The implementation of several biogas plants involves the conversion of organic carbon into biogas and the presence of elevated nitrogen and phosphorus compounds in the effluent. Treatment of such waste streams is costly with traditional methods (nitrification-denitrification), which require adding organic carbon back to the treatment process (often in the form of methanol). Among wastewater treatment technologies, the anaerobic ammonium oxidation process (anammox) has been incorporated into autotrophic nitrogen removal in pilot and full-scale technologies for nitrogen removal from waste with low organic carbon content. The mainstream can be called domestic sewage, and the side stream centrifuged anaerobic sludge reject water. The latter is formed after the fermentation and centrifugation of excess sludge. Attempts have been made to incorporate the anammox process into both sidestream and mainstream treatment using moving media biofilm reactor (MBBR) and batch scrubber (SBR) technologies. The main obstacles to be overcome in order to achieve a successful use of the anammox process in the mainstream are the high carbon to nitrogen ratio of the waste (C/N > 1) and the low temperature of the wastewater (12.5–19 °C present in the Nordic climate). Previous studies using the mainstream anammox process have shown that low temperatures can cause problems with anammox biomass growth. To overcome the inhibitory effect of cold temperatures on the growth rate of anammox bacteria, the mainstream system can be inoculated with biomass grown under side stream conditions. Changes in redox potential (ORP) affect the composition of proteins vital to bacteria or the charge of bacterial mitochondrial membranes. ORP changes can be controlled by turning aeration on/off or changing aerator-specific intensity changes using the ORP sensor signal and appropriate value ranges. The salinity of the wastewater and the effect of hydrazine are important parameters to evaluate the course of the anammox process. Achieving an optimal salinity level increases the activity of the anammox process and the rate of nitrogen removal. An intermediate in the anammox process, hydrazine, can affect the efficiency of the anammox process but also reduces other processes, such as denitrification, to achieve high nitrogen removal autotrophically.
The increase in the amount of generated waste today threatens the quality of the environment and human health. Biological treatment of wastewater is an energy-efficient way to remove organic and inorganic pollutants from wastewater and to reduce the likelihood of residues entering the groundwater. The implementation of several biogas plants involves the conversion of organic carbon into biogas and the presence of elevated nitrogen and phosphorus compounds in the effluent. Treatment of such waste streams is costly with traditional methods (nitrification-denitrification), which require adding organic carbon back to the treatment process (often in the form of methanol). Among wastewater treatment technologies, the anaerobic ammonium oxidation process (anammox) has been incorporated into autotrophic nitrogen removal in pilot and full-scale technologies for nitrogen removal from waste with low organic carbon content. The mainstream can be called domestic sewage, and the side stream centrifuged anaerobic sludge reject water. The latter is formed after the fermentation and centrifugation of excess sludge. Attempts have been made to incorporate the anammox process into both sidestream and mainstream treatment using moving media biofilm reactor (MBBR) and batch scrubber (SBR) technologies. The main obstacles to be overcome in order to achieve a successful use of the anammox process in the mainstream are the high carbon to nitrogen ratio of the waste (C/N > 1) and the low temperature of the wastewater (12.5–19 °C present in the Nordic climate). Previous studies using the mainstream anammox process have shown that low temperatures can cause problems with anammox biomass growth. To overcome the inhibitory effect of cold temperatures on the growth rate of anammox bacteria, the mainstream system can be inoculated with biomass grown under side stream conditions. Changes in redox potential (ORP) affect the composition of proteins vital to bacteria or the charge of bacterial mitochondrial membranes. ORP changes can be controlled by turning aeration on/off or changing aerator-specific intensity changes using the ORP sensor signal and appropriate value ranges. The salinity of the wastewater and the effect of hydrazine are important parameters to evaluate the course of the anammox process. Achieving an optimal salinity level increases the activity of the anammox process and the rate of nitrogen removal. An intermediate in the anammox process, hydrazine, can affect the efficiency of the anammox process but also reduces other processes, such as denitrification, to achieve high nitrogen removal autotrophically.
Description
Väitekirja elektrooniline versioon ei sisalda publikatsioone
Keywords
wastewater treatment, biological wastewater treatment, biofilm, nitrogen removal