Dataset Information

Analysis of the Partial Nitrification Process Affected by Polyvinylchloride Microplastics in Treating High-Ammonia Anaerobic Digestates.

ABSTRACT: Large amounts of microplastics entering into wastewater treatment plants are retained as wasted sludges, which are usually transferred to the anaerobic digestion process afterward. The partial nitrification (PN) process is known for treating the high ammonia anaerobic digestate; its treatment performance that is affected by the existence of microplastics is rarely reported. This study investigated the effect of microplastics on the PN process with polyvinylchloride (PVC) abundances at 0, 1000, 5000, and 10,000 particles/L. Results indicated that the corresponding nitrite transfer rates with the existence of PVC were 90.97, 64.24, 52.88, and 46.66%. The ammonia oxidation rate was reduced to 0.69, 0.55, and 0.49 times as compared with control. The average dissolved nitrous oxide (N2O) emission was also mitigated to 0.58, 0.49, and 0.64 times with added microplastics as compared with control. The average gaseous form of N2O emitted was mitigated to 0.54, 0.45, and 0.37 times as compared with control. The first-order kinetic model fitted well with all tests. The highest NO2-N generation potential was found in the blank reactor at a coefficient of 1430.1 (R 2 = 0.9776), which was 1.9-2.3 times higher than the other reactors with added microplastics. This study indicated that PVC inhibited the PN process and mitigated N2O emission during such a process. The microplastic contamination effects on high-ammonia wastewater treatment during the PN process must be considered for investigation.

SUBMITTER: Song K

PROVIDER: S-EPMC7513334 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Analysis of the Partial Nitrification Process Affected by Polyvinylchloride Microplastics in Treating High-Ammonia Anaerobic Digestates.

Song Kang K Li Zhouyang Z Liu Dan D Li Lu L

ACS omega 20200908 37

Large amounts of microplastics entering into wastewater treatment plants are retained as wasted sludges, which are usually transferred to the anaerobic digestion process afterward. The partial nitrification (PN) process is known for treating the high ammonia anaerobic digestate; its treatment performance that is affected by the existence of microplastics is rarely reported. This study investigated the effect of microplastics on the PN process with polyvinylchloride (PVC) abundances at 0, 1000, 5 ...[more]

PMID: 32984703

Similar Datasets

Project description:The aim of the study was enrichment of nitrifying bacteria and to investigate the potential of autotrophic fixed-film and hybrid bioreactors to treat high strength ammonia wastewater (up to 1,000 mg N/L). Two types of fixed-film systems [moving bed biofilm reactor (MBBR) and BioCordTM] in two different configurations [sequencing batch reactor (SBR) and a continuous stirred tank reactor (CSTR)] were operated for 306 days. The laboratory-scale bioreactors were seeded with activated sludge from a municipal wastewater treatment plant and fed synthetic wastewater with no organics. Strategies for acclimation included biomass reseeding (during bioreactor start-up), and gradual increase in the influent ammonia concentration [from 130 to 1,000 mg N/L (10% every 5 days)]. Stable ammonia removal was observed up to 750 mg N/L from 45 to 145 days in the MBBR SBR (94-100%) and CSTR (72-100%), and BioCordTM SBR (96-100%) and CSTR (92-100%). Ammonia removal declined to 87% ± 6, in all bioreactors treating 1,000 mg N/L (on day 185). Following long-term operation at 1,000 mg N/L (on day 306), ammonia removal was 93-94% in both the MBBR SBR and BioCordTM CSTR; whereas, ammonia removal was relatively lower in MBBR CSTR (20-35%) and BioCordTM SBR (45-54%). Acclimation to increasing concentrations of ammonia led to the enrichment of nitrifying (Nitrosomonas, Nitrospira, and Nitrobacter) and denitrifying (Comamonas, OLB8, and Rhodanobacter) bacteria [16S rRNA gene sequencing (Illumina)] in all bioreactors. In the hybrid bioreactor, the nitrifying and denitrifying bacteria were relatively more abundant in flocs and biofilms, respectively. The presence of dead cells (in biofilms) suggests that in the absence of an organic substrate, endogenous decay is a likely contributor of nutrients for denitrifying bacteria. The nitrite accumulation and abundance of denitrifying bacteria indicate partial denitrification in fixed-film bioreactors operated under limited carbon conditions. Further studies are required to assess the contribution of organic material produced in autotrophic biofilms (by endogenous decay and soluble microbial products) to the overall treatment process. Furthermore, the possibility of sustaining autotrophic nitrogen in high strength waste-streams in the presence of organic substrates warrants further investigation.

Project description:BackgroundAnaerobic digesters become unstable when operated at a high organi c loading rate (OLR). Investigating the microbial community response to OLR disturbance is helpful for achieving efficient and stable process operation. However, previous studies have only focused on community succession during different process stages. How does community succession influence process stability? Is this kind of succession resilient? Are any key microbial indicator closely related to process stability? Such relationships between microbial communities and process stability are poorly understood.ResultsIn this study, a mesophilic anaerobic digester for treating food waste (FW) was operated to study the microbial diversity and dynamicity due to OLR disturbance. Overloading resulted in proliferation of acidogenic bacteria, and the resulting high volatile fatty acid (VFA) yield triggered an abundance of acetogenic bacteria. However, the abundance and metabolic efficiency of hydrogenotrophic methanogens decreased after disturbance, and as a consequence, methanogens and acetogenic bacteria could not efficiently complete the syntrophy. This stress induced the proliferation of homoacetogens as alternative hydrogenotrophs for converting excessive H2 to acetate. However, the susceptible Methanothrix species also failed to degrade the excessive acetate. This metabolic imbalance finally led to process deterioration. After process recovery, the digester gradually returned to its original operational conditions, reached close to its original performance, and the microbial community profile achieved a new steady-state. Interestingly, the abundance of Syntrophomonas and Treponema increased during the deteriorative stage and rebounded after disturbance, suggesting they were resilient groups.ConclusionsAcidogenic bacteria showed high functional redundancy, rapidly adapted to the increased OLR, and shaped new microbial community profiles. The genera Syntrophomonas and Treponema were resilient groups. This observation provides insight into the key microbial indicator that are closely related to process stability. Moreover, the succession of methanogens during the disturbance phase was unsuitable for the metabolic function needed at high OLR. This contradiction resulted in process deterioration. Thus, methanogenesis is the main step that interferes with the stable operation of digesters at high OLR. Further studies on identifying and breeding high-efficiency methanogens may be helpful for breaking the technical bottleneck of process instability and achieving stable operation under high OLR.

Dataset Information

Analysis of the Partial Nitrification Process Affected by Polyvinylchloride Microplastics in Treating High-Ammonia Anaerobic Digestates.

Publications

Analysis of the Partial Nitrification Process Affected by Polyvinylchloride Microplastics in Treating High-Ammonia Anaerobic Digestates.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets