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Elucidation of Microbial Diversity in Wastewater Treatment System Through Molecular Tools: Molecular Tools, Techniques, and Applications in Wastewater Treatment
Published in Maulin P. Shah, Wastewater Treatment, 2022
Nikhil Nair, Sanchita Patwardhan, Nilesh S. Wagh, Jaya Lakkakula, Nomvano Mketo
The goal of this study was to substantiate FISH on samples taken of activated sludge and biofilms from wastewater plants for the comparison of data published abroad. FISH was used along with 16S rRNA-targeted probes. The AOB and NOB were identified using the following fluorescent-labeled probes: NSO1225 and NSO190 for the β-AOB, NEU for most halophilic and halotolerant Nitrosomonas spp., Nsv443 for Nitrosospira spp., NmV for Nitrosococcus mobilis, Ntspa712 and Ntspa662 for most of the members of the phylum Nitrospirae and genus Nitrospira, NIT3 for Nitrobacter spp., Ntcoc206 for N. mobilis and Ntspn693 for Nitrospina gracilis, EUB338II (specific for Planctomycetales) and EUB338III (specific for Verrucomicrobia) were used for the detection of almost all the members of the domain Bacteria. Laser scanning confocal microscopes (LSCMs) were used for analysis. Using FISH, it was found that AOB were responsible for the conversion of ammonia to nitrite, and Nitrospira spp. was responsible for oxidation of nitrite to nitrate, which belonged to β-Proteobacteria. the nitrifying bacteria formed clusters of various shapes and sizes, with the exception of Nitrospira, which existed as single cells [18].
Advanced treatment processes
Published in Rumana Riffat, Taqsim Husnain, Fundamentals of Wastewater Treatment and Engineering, 2022
The term deammonification is used to describe an ammonium removal process that does not depend on the supply of organic matter (Hippen et al., 1997). It uses aerobic and anaerobic ammonium oxidizers to convert ammonium directly to nitrogen gas under oxygen-limited conditions. The ammonium reacts with nitrite acting as an electron acceptor to produce nitrogen gas. The anaerobic ammonium oxidizers or Anammox bacteria were discovered by Mulder et al. (1995) in a fluidized bed reactor. The Anammox bacteria belong to the phylum Planctomycetales. They have a very low growth rate of 0.072 d−1 with a mass doubling time of 11 d, which can be an obstacle in process start-up (Jetten et al., 2001). The overall process is illustrated in Figure 13.9.
Introduction
Published in Moustafa Samir Moussa, Nitrification in Saline Industrial Wastewater, 2014
The denitrifying bacteria (as described above) are not the only bacteria producing nitrogen gas. Ammonia can be oxidized under anaerobic conditions also leading to N2 and it became clear that slow growing autotrophic bacteria belonging to the order of the Planctomycetales are carrying out this process. This process, in which both ammonia and nitrite are converted to N2, is called ANAMMOX, an acronym for ANaerobic AMMonia OXidation (Mulder et al 1995; Schmidt et al 2003).
Effect of ammonium to nitrite ratio on reactor performance and microbial population structure in anammox reactors
Published in Environmental Technology, 2020
Nomalanga P. Gasa, Chika F. Nnadozie, Kiprotich Kosgey, Faizal Bux, Sheena Kumari
Anaerobic ammonium oxidation (anammox) is a more environmentally sustainable and cost-effective technology alternative for nitrogen removal from ammonium-rich wastewater [1]. The anammox process is carried out by anammox bacteria, which oxidize ammonia under anoxic conditions, with nitrite as electron acceptor to produce dinitrogen gas [2]. Anammox bacteria belong to the order Planctomycetales. To date, six Candidatus genera of anammox bacteria have been defined including: Brocadia, Kuenenia, Scalindua, Jettenia, Anammoxomicrobium and Anammoxoglobus [2]. Anammox bacteria have not yet been isolated as pure cultures because they coexist with other microbial species [2]. Previous studies have demonstrated the co-culture of anammox bacteria, ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) inside the same reactor under oxygen limited conditions [3]. Under these conditions, the AOB can provide nitrite to the anammox bacteria, an interaction analogous to that in completely autotrophic nitrogen-removal over nitrite (CANON) process [3]. Furthermore, where oxygen is not completely reduced, NOB may proliferate. Therefore, the microbial community of an anammox reactor can be dominated by the three microbial groups, namely anammox bacteria, AOB and NOB [3].
Mainstream-sidestream wastewater switching promotes anammox nitrogen removal rate in organic-rich, low-temperature streams
Published in Environmental Technology, 2021
Ivar Zekker, Markus Raudkivi, Oleg Artemchuk, Ergo Rikmann, Hans Priks, Madis Jaagura, Taavo Tenno
Considering anammox bacteria, DNA sequences belonging to uncultured Planctomycetales bacterium Candidatus Brocadia were detected at the highest quantities from biomass taken during mainstream operation (7.6%), followed by the anammox species Planctomyces and Candidatus anammoximicrobium, the quantities of which were highest for the sidestream operation period, followed by mainstream operation and inoculum bacterial abundances. Earlier, using ammonium, nitrite and bicarbonate enabled to achieve the enrichment of Candidatus Brocadia fulgida [20] and Planctomycetes clone P4 [17].
Potential of suspended growth biological processes for mixed wastewater reclamation and reuse in agriculture: challenges and opportunities
Published in Environmental Technology Reviews, 2021
Precious N. Egbuikwem, Gregory C. Obiechefu, Faisal I. Hai, Ma. Catriona E. Devanadera, Devendra P. Saroj
Alternative to the conventional nitrification–denitrification pathway for biological nitrogen removal is anaerobic ammonium oxidation (anammox) process which converts ammonium and nitrite directly to nitrogen gas by anammox bacteria. There are two-step reactions involved in anammox-based processes: partial oxidation of ammonium to nitrite with low DO by AOB, and subsequent oxidation of nitrite to nitrogen gas under anoxic conditions by anammox bacteria such as Planctomycetales [101]. Anammox process has received considerable attention in recent years as an innovative and resource-efficient process considering particularly its relatively minimal oxygen requirements and less sludge production. The process allows a short-cut for nitrogen removal through partial nitrification to nitrite (nitritation) which is then used for anammox activity. In more specific terms, the stoichiometric values for oxygen and carbon requirements and sludge production in anammox process given as 3.43 g-O2/g-N, 1.71 g-COD/g-N and 0.73 g-VSS/g-N, respectively are substantially lower than the corresponding values 4.57 g-O2/g-N, 2.86 g-COD/g-N and 1.19 g-VSS/g-N for conventional nitrification–denitrification pathway [102], adding that anammox process reduces power requirements by 64%, COD demand by 100% and sludge production by 80–90% [102]. For stability and efficiency of anammox process in biological nitrogen removal, conditions that promote nitritation over nitrification, such as enrichment of AOB over NOB, suppression of nitrite oxidation, etc. need to be applied. Like the traditional nitrification–denitrification process, the effectiveness of anammox process depends on operational factors, such as dissolved oxygen level, organic carbon content, substrate concentration, nitrogen loading, temperature and pH condition and sludge retention time [103,104]. Although the conventional biological nitrogen removal was originally developed to take place in two-stage reactors, studies have shown that both the nitrification–denitrification process and anammox process could be operated efficiently in a single-stage reactor by the proper management of dissolve oxygen concentration and selection of appropriate operational conditions [101,105].