The development of an analytical method for the determination of total organic-bound chlorine (TOCl) produced during the chlorination of municipal wastewater effluents is presented. Sewage effluent from the Denton, Texas municipal treatment plant was chlorinated at high chlorine doses (1000 - 4000 ppm), as well as typical treatment levels. Chlororganics present in the wastewater, before and after chlorination, were concentrated by adsorption on Amberlite XAD-2 macroreticular resin, followed by elution with diethyl ether. After concentration, the extracts were analyzed for TOC1 by microcoulometry. Analysis of wastewater extracts revealed the production of substantial amounts of new chlorinated organics when effluents were treated with chlorine. The method shows good precision and estimated accuracy is favorable.

Οι Μεσογειακές χώρες ετησίως, κατά την παραγωγή του ελαιολάδου, έρχονται αντιμέτωπες με τη διαχείριση των υγρών αποβλήτων των ελαιοτριβείων, τα οποία περιέχουν μεγάλες ποσότητες οργανικών ουσιών και αιωρούμενων στερεών, προερχόμενα από τον καρπό και το χρησιμοποιούμενο νερό κατά τη μεταποιητική διαδικασία. Η απόρριψή τους στο περιβάλλον ρυπαίνει υδροφόρους ορίζοντες και επιφανειακά ύδατα, υποβαθμίζει το έδαφος, προκαλεί τοξικότητα και δυσάρεστη οσμή. Πλήθος φυσικοχημικών, αλλά και βιολογικών μεθόδων έχουν δοκιμασθεί στην προσπάθεια εξάλειψης των δυσμενών τους χαρακτηριστικών, χωρίς να έχουν δώσει σε ευρεία κλίμακα λύση, προσκρούοντας κυρίως σε προβλήματα κόστους εγκατάστασης και λειτουργίας καθώς και στη διακύμανση της σύστασης τους. Στόχος της παρούσας έρευνας είναι η μελέτη της συμπεριφοράς των υγρών ελαιουργικών λυμάτων κατά τη διοχέτευση τους σε μονάδα επεξεργασίας αστικών λυμάτων, ώστε να είναι δυνατή η συνεπεξεργασία των δύο αυτών διαφορετικών ειδών λυμάτων και να διερευνηθεί η δυνατότητα χρήσης ενός αντιδραστήρα ενεργού ιλύος με προσροφητικό υλικό, PVA-gels Biocarriers. Δημιουργήθηκαν 6 αντιδραστήρες με συγκεκριμένες αραιώσεις κατσίγαρου προς αστικά λύματα, σε συγκεντρώσεις ½, 1/10 και 1/100. Στο υπερκείμενο των συνθετικών λυμάτων πραγματοποιούνταν μετρήσεις των φυσικοχημικών χαρακτηριστικών του ανεπεξέργαστου και επεξεργασμένου συνθετικού λύματος περιοδικά έως το τέλος της πειραματικής διαδικασίας (16/1/2011). Επίσης εξετάστηκε η μικροβιακή χλωρίδα του επεξεργασμένου συνθετικού λύματος και η αποκατάστασή της. Παρατηρήθηκε ότι όλα τα συστήματα επεξεργάζονταν ικανοποιητικά απόβλητα που περιείχαν ελαιουργικά λύματα σε αναλογία 1/100 κατ’ όγκο, ότι η μικροβιακή τους χλωρίδα αποκαθίσταται, και θα μπορούσαν να διατεθούν σε φυσικό αποδέκτη, ικανοποιώντας τα περισσότερα κριτήρια της οδηγίας 91/271/ΕΕC. Στα συστήματα με αναλογία ½ και 1/10 κατ’ όγκο, παρατηρήθηκε αξιόλογη επεξεργασία σε κάποιες παραμέτρους αλλά και πάλι ήταν υψηλότερη από τα όρια διάθεσης. Τέλος, δεν παρατηρήθηκε κάποια αξιόλογη διαφοροποίηση μεταξύ των δύο συστημάτων ενεργού ιλύος με και χωρίς Biocarriers, τουλάχιστον για αυτό το πρώτο στάδιο εισαγωγής των Biocarriers. / Every year Mediterranean countries face the same problem of the olive oil mill wastewater management. This type of wastewater contains high concentration of organic loads and particulate suspended matter originating from the olives and the production water. Dumping this kind of wastewater untreated to the environment pollutes both surface and groundwater, degrades the soil quality and creates toxic environments and unpleasant odors. Several physicochemical as well as biological methods have been tested unsuccessfully due to the construction and operational costs as well as the variability of the wastewater characteristics. The goal of the present research is to study the behavior of the olive oil mill wastewater while it is introduced in a municipal wastewater treatment plant. The use of PVA-gels as Biocarriers in such a system is also tested. Six bioreactors were used with constant ratios of olive oil mill wastewater to municipal wastewater equal to ½, 1/10, and 1/100. The physicochemical parameters of the supernatant were measured periodically till the end of the experiment (16/1/2011). In addition the microbial communities of the different reactors were monitored especially after the return to the normal operation with municipal wastewater. Both systems treat the olive oil mill wastewater mixed with municipal wastewater in a ratio of 1/100 satisfactorily with outflow that could be discarded to natural receiver being close to the requirements set by the European directive 91/271/ΕΕC. Also, after the return to the normal operation with municipal wastewater the microbial community was easily restored. In systems with such ratios equal to ½ and 1/10, the treatment is effective but the outflow is high over the limits set for municipal wastewater treatment plants. Finally, no significant deviation was observed for activated sludge systems with and without Biocarriers for this initial stage of Biocarriers introduction.

Nitrogen removal from wastewater has been exstensively addressed by scientific literature in recent years; one of the most widely implemented technologies consists of the combination of partial nitritation and anaerobic ammonium oxidation (ANAMMOX). Compared to traditional nitrification and denitrification techniques such solution eliminates the requirement for an external carbon source and allows for a reduced production of excess sludge; furthermore, it brings down the costs associated to aeration by 60-90% and the emissions of CO2 by 90%. Similar techniques can turn out to be particularly interesting when stringent environmental regulations have to be met. At present, most of the dedicated research dwells on wastewater at high temperatures, high nitrogen loads and low organic content, as it is typical of sidestream effluents; this project, instead, is focused on mainstream wastewater, characterized by lower temperatures and nitrogen content, but higher COD values. At the center of the thesis is the application of a one-stage reactor treating synthetic mainstream municipal wastewater. The chosen approach consisted in maintaining low DO values, allowing for both for the establishment of a proper reaction environment and for the out-selection of nitrite oxidizers; granular biomass was employed for the experiment, aiming at effective biomass retention. The HRT value was gradually decreased, with a minimum at 6 hours. Resulting nitrogen removal rates proved to be satisfactory, with a maximum TN removal efficiency of 54%. Retention of biomass was also positively enhanced throughout the experiment, and yielded a final SRT value of 15.6 days. The whole process was then inserted into a more complete framework, accounting for possible energetic optimizations of similar treatment plants. Employing COD fractionation as a primary step paves the way for anaerobic digestion side processes, which can produce methane and ultimately provide energy for the main nitrogen removal step. Therefore, envisioning energy-sufficient water treatment processes seems a more and more feasible and realistic possibility.

Many pharmaceuticals are found in municipal wastewater effluents due to their persistence in the human body as well as in conventional wastewater treatment processes. This discharge to the environment can lead to adverse effects in aquatic species, such as feminization of male fish. During the past decade, these findings have spawned investigations and research into suitable treatment technologies that could severely limit the discharge. Adsorption onto activated carbon has been identified as one of the two main technologies for implementation of (future) full-scale treatment. Recent research has put a closer focus on adsorption with powdered activated carbon (PAC) than on granular activated carbon (GAC). Studies where both methods are compared in parallel operation are thus still scarce and such evaluation in pilot-scale was therefore a primary objective of this thesis. Furthermore, recirculation of PAC can be used to optimize the treatment regarding the carbon consumption. Such a setup was evaluated as a separate treatment stage to comply with Swedish wastewater convention. Additionally, variation of a set of process parameters was evaluated. During successive operation at three different wastewater treatment plants an overall pharmaceutical removal of 95% could consistently be achieved with both methods. Furthermore, treatment with GAC was sensitive to a degraded effluent quality, which severely reduced the hydraulic capacity. Both treatment methods showed efficient removal of previously highlighted substances, such as carbamazepine and diclofenac, however in general a lower adsorption capacity was observed for GAC. By varying the input of process parameters, such as the continuously added dose or the contact time, during PAC treatment, a responsive change of the pharmaceutical removal could be achieved. The work in this thesis contributes some valuable field experience towards wider application of these treatment technologies in full-scale. / <p>QC 20161124</p> / MistraPharma

Denna rapport presenterar resultat och analys av prestandan i ett pilotförsök om temperaturstegsrötning (TPAD). Pilotförsöket genomfördes på uppdrag av Käppalaförbundet. Resultaten jämfördes med en nedskalad mesofil process som simulerade den nuvarande fullskaliga rötningsprocessen på Käppala  avloppsreningsverk. Syftet var att utvärdera om TPAD kunde erbjuda fördelar jämfört med det mesofila systemet. TPAD har tidigare visat stor potential i pilotstudier och till viss del i fullskaliga implementeringar på avloppsreningsverk runt om i världen. Då prestanda och beteende vid rötningsprocesser dock är starkt beroende av lokal slamkomposition och processparametrar, behövdes en skräddarsydd pilotstudie för att utvärdera TPADs applicerbarhet vid Käppala avloppsreningsverk specifikt. Sammanfattningsvis visade TPAD något bättre metanutbyte än det mesofila kontollförsöket (MAD), och VSD ökade markant. Dessa fördelar erhölls trots den lägre totala retentionstiden för TPAD. Kvävemineraliseringen ökade dock också märkbart vilket potentiellt kan medföra ökade kostnader associerade med rening av kväve i rejektvattnet för avloppsreningsverket. Avvattningsprov på labbskala visade ett omfattande utsläpp av TSS i rejektvattnet efter det termofila rötningssteget. Detta förbättrades dock avsevärt (om än inte i samma utsträckning som MAD) efter det mesofila skedet. Mycket preliminära resultat indikerade att TPAD hade en utmärkt inneboende hygieniseringsförmåga tack vare det termofila skedet, och resulterade i ett slutgiltigt rötslam som uppfyllde hygieniseringsriktlinjer enligt Revaq. TPAD verkade uppvisa hög robusthet, utan någon uppenbar syrakollaps trots hög belastning i det termofila steget. Framtida stresstester föreslås för att tvinga fram en termofil syrakollaps, vilket skulle kunna ge en syra/gas-fasad TPAD, med potentiellt ytterligare ökad prestanda enligt mycket av den befintliga litteraturen. / This report analyzes the performance of a pilot scale temperature phased anaerobic digestion process (TPAD) undertaken on commission from the Käppalaförbundet wastewater treatment plant. Results from the newly initiated TPAD pilot were compared to those of a scaled down mesophilic process simulating the current full scale digestion used at Käppala, to evaluate whether TPAD could provide benefits over the mesophilic system. TPAD had previously showed great promise at pilot and full scale at other plants around the world, but given that anaerobic digestion performance and behavior are highly dependent on local sludge composition and process parameters, a bespoke pilot was needed to evaluate TPAD at Käppala WWTP specifically. In summary, the TPAD exhibited slightly better methane yields than the mesophilic control, and showed better removal of volatile solids. Such benefits were seen despite the lower overall retention time of the TPAD. Nitrogen mineralisation however also increased, potentially imposing increased costs associated with sludge liquor nitrogen purification. Dewaterability tests showed the thermophilic stage of TPAD releasing large amounts of problematic colloidal material, which however was reduced by the subsequent mesophilic stage. Preliminary results indicated the TPAD had an excellent inherent hygienization ability owing to the thermophilic stage, producing a final digestate which fulfilled Revaq hygienization guidelines. The TPAD also seemed to exhibit great robustness, with no acid collapse in the thermophilic stage apparent despite high loads and short retention times. Future stress tests are proposed to test an acid-gas phased TPAD, with potentially further increased performance as per much of the existing literature.

High costs for aeration, greenhouse-gas emissions and excess sludge disposal have entailed a paradigm shift in the wastewater treatment. Microalgal-bacterial-based wastewater treatments have gained increasing attention because of their potential in energy demand reduction and biomass resource recovery. In particular, photosynthetic oxygenation is combined with bacterial activity to treat wastewater avoiding external artificial aeration. To optimize the technology in order to become more competitive than activated sludge, an in-depth investigation about the treatment performance and the microbiology interactions under real operational condition is needed. This work focused on the study of wastewater-borne microalgal-bacterial consortia treating real municipal wastewater. The main objectives were to: (i) Understand the removal mechanisms and the influence of operational conditions to optimize the process; (ii) Analyze the microbial community. At first, a photo-sequencing batch reactor (PSBR), called Pilot, was started up and continuously monitored for two years to analyze the evolution of the treatment performance and of the biomass composition. At the same time, other two lab-scale PSBRs were installed to evaluate if microalgal inoculation is essential to start up a consortium. Samples of these consortia were collected over a period of one year and analyzed through microscopic observations, flow cytometry and metagenomics, to investigate the microbial structure and diversity.A second part of the research focused on the optimization of the Pilot to explore its limit in view of the scale-up of the system. In addition, respirometry was adapted to test microalgal-bacterial consortia to estimate the removal kinetic parameters for future modelling. To conclude, the research project addressed many aspects and lay the foundation to apply a methodological research approach to scale-up this promising technology.

Nessa pesquisa foi realizado um estudo experimental da potencialidade do emprego da ozonização após tratamento anaeróbio de efluentes, no que se refere a dosagem, tempo de contato, alcalinidade, aplicação conjunta com peróxido de hidrogênio, quantidade de ozônio consumida e oxidação de matéria orgânica. O estudo proposto foi executado por meio de: (a) estudos preliminares; (b) testes preliminares; (c) experimento I, empregando ozônio sem variação da alcalinidade afluente; (d) experimento II, empregando ozônio com variação da alcalinidade afluente; (e) experimento III, empregando ozônio combinado com peróxido de hidrogênio sem variação da alcalinidade afluente; (f) verificação da desinfecção; (g) análise crítica dos resultados. Fez-se comparação entre os parâmetros de análise, a dosagem de ozônio consumida e o tempo de contato e entre a qualidade do efluente ozonizado e os critérios de qualidade para reuso de efluentes, permitindo chegar as seguintes conclusões: (i) a maior parte do teor de ozônio consumido durante a ozonização é consumido nos primeiros 5 minutos; (ii) o consumo de ozônio pode ser melhor entendido analisando-se a variável dose instantânea aplicada de ozônio; (iii) o comportamento da transferência de ozônio é influenciado por três fatores: hidrodinâmica do reator, quantidade de ozônio, disponível para reagir e características do efluente; (iv) a variação no pH indica o grau de oxidação atingido no processo; (v) a presença de nitrato favorece a oxidação;(vi) a ozonização é um processo muito eficiente para desinfetar efluentes. A inativação de coliformes totais e fecais atingiu 7,51 e 6,98 Log, respectivamente; (vii) a massa de ozônio por tempo regula a taxa de remoção de DQO enquanto a dose média, a eficiência de remoção de DQO; (viii) Com o consumo de 32,46 +/- 8,19 mg/L de ozônio em 25 minutos de ozonização chegou-se a remoção média de DQO e Turbidez de 48,33 mais ou menos 2,90% e 89,22 +/- 0,35%, respectivamente; (ix) a adição de peróxido de hidrogênio melhorou significativamente a eficiência de remoção de DQO e de carbono. Sem adicionar o peróxido de hidrogênio, precisou-se de 25 minutos de ozonização para se atingir cerca de 25% de remoção de DQO; enquanto que, adicionando peróxido de hidrogênio na razão O3/H2O2 de aproximadamente 0,30, este tempo foi de apenas 10 minutos e a remoção de carbono total dobrou de valor; (x) o efluente ozonizado deve passar por tratamento adicional antes de ser lançado no corpo receptor ou ser reusado. / In this research an experimental study of the potentiality of employment of the ozonization was accomplished after anaerobic treatment, in what refers the dose, time of contact, alkalinity, application combined with hydrogen peroxide, amount of consumed ozone and oxidation of organic matter. The proposed study was executed by means of: (a) preliminary studies; (b) preliminary tests; (c) experiment I, using ozone without variation of the affluent alkalinity; (d) experiment II, using ozone with variation of the affluent alkalinity; (and) experiment III, using ozone combined with hydrogen peroxide without variation of the affluent alkalinity; (f) verification of the disinfection; (g) critical analysis of the results. The results were analyzed by means of graphs, it was make itself comparison among analysis parameters, transferred ozone dose and time of contact and among quality of ozonized effluent and quality criterion for effluent reuse. Permitting arrive the following conclusions: (i) the most of the content of consumed ozone during the ozonization is consumed in the first 5 minutes; (ii) the consumed ozone can be better understood analyzing itself the variable applied instant ozone dose; (iii) the behavior from the ozone transference is influenced by three factors: hydrodynamic of the reactor, quantity of ozone available to react and characteristics of the effluent; (iv) the change in pH shows the reached rank of oxidation in the process; (v) the presenceof nitrate favors to oxidation; (vi) the ozonization is a very efficient process to disinfect effluent. The inativation of total and fecal coliforms reached 7,51 and 6,98 Log, respectively; (vii) the mass of ozone controls the rate of COD removal while the medium dose controls the efficiency of COD removal; (viii) with the consumption of ozone of 32,46 +/- 8,19 mg/L in 25 minutes of ozonization, it arrived COD and turbidity medium removals of 48,33 +/- 2,90% and 89,22 +/- 0,35%, respectively; (ix) the addition of hydrogen peroxide improved significantly the efficiency of COD and carbon removal. Without adding hydrogen peroxide, it was needed 25 minutes of ozonization to reach about 25% of COD removal; while that, adding hydrogen peroxide in reason O3/H2O2of approximately 0,30, this time was only 10 minutes and total carbon removal double; (ix) the ozonized e to be submitted an additional treatment before of its discharge in the surface water or its reused.

A study has been conducted for the qualitative and Quantitative analysis of chlorinated organic compounds in water. The study included the adaptation of Amberlite XAD macroreticular resin techniques for the concentration of municipal wastewater samples, followed by GC/MS analysis. A new analytical method was developed for the determination of volatile halogenated organics using liquid-liquid extraction and electron capture gas chromatography. And, a computer program was written which searches raw GC/MS computer files for halogen-containing organic compounds.

Nessa pesquisa foi realizado um estudo experimental da potencialidade do emprego da ozonização após tratamento anaeróbio de efluentes, no que se refere a dosagem, tempo de contato, alcalinidade, aplicação conjunta com peróxido de hidrogênio, quantidade de ozônio consumida e oxidação de matéria orgânica. O estudo proposto foi executado por meio de: (a) estudos preliminares; (b) testes preliminares; (c) experimento I, empregando ozônio sem variação da alcalinidade afluente; (d) experimento II, empregando ozônio com variação da alcalinidade afluente; (e) experimento III, empregando ozônio combinado com peróxido de hidrogênio sem variação da alcalinidade afluente; (f) verificação da desinfecção; (g) análise crítica dos resultados. Fez-se comparação entre os parâmetros de análise, a dosagem de ozônio consumida e o tempo de contato e entre a qualidade do efluente ozonizado e os critérios de qualidade para reuso de efluentes, permitindo chegar as seguintes conclusões: (i) a maior parte do teor de ozônio consumido durante a ozonização é consumido nos primeiros 5 minutos; (ii) o consumo de ozônio pode ser melhor entendido analisando-se a variável dose instantânea aplicada de ozônio; (iii) o comportamento da transferência de ozônio é influenciado por três fatores: hidrodinâmica do reator, quantidade de ozônio, disponível para reagir e características do efluente; (iv) a variação no pH indica o grau de oxidação atingido no processo; (v) a presença de nitrato favorece a oxidação;(vi) a ozonização é um processo muito eficiente para desinfetar efluentes. A inativação de coliformes totais e fecais atingiu 7,51 e 6,98 Log, respectivamente; (vii) a massa de ozônio por tempo regula a taxa de remoção de DQO enquanto a dose média, a eficiência de remoção de DQO; (viii) Com o consumo de 32,46 +/- 8,19 mg/L de ozônio em 25 minutos de ozonização chegou-se a remoção média de DQO e Turbidez de 48,33 mais ou menos 2,90% e 89,22 +/- 0,35%, respectivamente; (ix) a adição de peróxido de hidrogênio melhorou significativamente a eficiência de remoção de DQO e de carbono. Sem adicionar o peróxido de hidrogênio, precisou-se de 25 minutos de ozonização para se atingir cerca de 25% de remoção de DQO; enquanto que, adicionando peróxido de hidrogênio na razão O3/H2O2 de aproximadamente 0,30, este tempo foi de apenas 10 minutos e a remoção de carbono total dobrou de valor; (x) o efluente ozonizado deve passar por tratamento adicional antes de ser lançado no corpo receptor ou ser reusado. / In this research an experimental study of the potentiality of employment of the ozonization was accomplished after anaerobic treatment, in what refers the dose, time of contact, alkalinity, application combined with hydrogen peroxide, amount of consumed ozone and oxidation of organic matter. The proposed study was executed by means of: (a) preliminary studies; (b) preliminary tests; (c) experiment I, using ozone without variation of the affluent alkalinity; (d) experiment II, using ozone with variation of the affluent alkalinity; (and) experiment III, using ozone combined with hydrogen peroxide without variation of the affluent alkalinity; (f) verification of the disinfection; (g) critical analysis of the results. The results were analyzed by means of graphs, it was make itself comparison among analysis parameters, transferred ozone dose and time of contact and among quality of ozonized effluent and quality criterion for effluent reuse. Permitting arrive the following conclusions: (i) the most of the content of consumed ozone during the ozonization is consumed in the first 5 minutes; (ii) the consumed ozone can be better understood analyzing itself the variable applied instant ozone dose; (iii) the behavior from the ozone transference is influenced by three factors: hydrodynamic of the reactor, quantity of ozone available to react and characteristics of the effluent; (iv) the change in pH shows the reached rank of oxidation in the process; (v) the presenceof nitrate favors to oxidation; (vi) the ozonization is a very efficient process to disinfect effluent. The inativation of total and fecal coliforms reached 7,51 and 6,98 Log, respectively; (vii) the mass of ozone controls the rate of COD removal while the medium dose controls the efficiency of COD removal; (viii) with the consumption of ozone of 32,46 +/- 8,19 mg/L in 25 minutes of ozonization, it arrived COD and turbidity medium removals of 48,33 +/- 2,90% and 89,22 +/- 0,35%, respectively; (ix) the addition of hydrogen peroxide improved significantly the efficiency of COD and carbon removal. Without adding hydrogen peroxide, it was needed 25 minutes of ozonization to reach about 25% of COD removal; while that, adding hydrogen peroxide in reason O3/H2O2of approximately 0,30, this time was only 10 minutes and total carbon removal double; (ix) the ozonized e to be submitted an additional treatment before of its discharge in the surface water or its reused.

This membrane aerated biofilm reactor (MABR) pilot project was performed at Ekeby wastewater treatment plant (WWTP) in Eskilstuna, Sweden. This plant is facing a future challenge of effluent TN &lt; 10mg/L according to the new standard and the growing population, where higher treatment capacity is needed. The MABR as a newly invented technology, is chosen as a promising countermeasure towards the challenge, because of the simultaneous nitrification and denitrification of this technology. By the time of reporting, this project is still on-going, and more information will be reported later in separate report. The feed water comes from the secondary clarifier of full-scale plant. Dissolved oxygen (DO), processing air and flow rate was manually controlled to test different operational settings. However, there were a lot challenges during the testing period which makes it hard to evaluate the performance of this pilot. The ammonium removal efficiency is satisfying when the pilot was running smoothly. However, the TN removal efficiency did not comply with the expectation, achieved in average of 39,01%, due to the limitation of readily bio-degradable COD (rbCOD), which is a limitation of the biological process in general and is not specific to MABR. This technology is considered as promising by the end of the current testing period, since it can oxidize the ammonium effectively with smaller volume. / Detta pilotprojekt med membranluftad biofilmreaktor (MABR) utfördes på Ekeby avloppsreningsverk i Eskilstuna, Sverige. Denna anläggning står inför en framtida utmaning med utflöde-TN &lt;10 mg / L enligt den nya standarden och den växande befolkningen, där högre behandlingskapacitet behövs. MABR som nyutvecklad teknik, väljs som en lovande motåtgärd för utmaningen på grund av den samtidiga nitrifikationen och denitrifikationen med denna teknik. Vid rapporteringstillfället är projektet fortfarande pågående och mer information kommer att rapporteras senare i separat rapport. Matarvattnet kommer från den sekundärfällningen i fullskaleanläggningen. Löst syre (DO), bearbetningsluft och flödeshastighet kontrollerades manuellt för att testa olika driftsinställningar. Det fanns emellertid många utmaningar under testperioden vilket gör det svårt att utvärdera prestanda för denna pilot. Ammoniumavlägsningsgraden var tillfredsställande när piloten körde smidigt. TN-avlägsningseffektiviteten som i genomsnitt uppnådde 39,01% TN-avlägsning motsvarade emellertid inte förväntan, på grund av begränsningen av lätt biologisk nedbrytbar COD (rbCOD), vilken är en begränsning av den biologiska processen i allmänhet och inte specifik för MABR. Denna teknik anses vara lovande vid slutet av den aktuella testperioden, eftersom den kan oxidera ammoniumen effektivt med en mindre volym.