•A concept of AnMBR-PN/A process was proposed for mainstream treatment.•In-situ FA/FNA exposure eliminated Nitrospira while retained Nitosonomas community.••DO limitation prevented switch of the NOB ...community in the mainstream conditions.•The effluent TN of the mainstream PN/A system was lower than 10 mg-N/L.•Enhanced hydrodynamic shear force resulted in sludge settleability deterioration.
In this pilot-scale study, an innovative mainstream treatment process that couples the anaerobic membrane reactor (AnMBR) with a one-stage PN/A system was proposed for advancing the concept of carbon neutrality in the municipal wastewater treatment plant. This work demonstrates the start-up procedure of a pilot-scale one-stage PN/A system for mainstream treatment. The 255-day start-up of the one-stage PN/A system involved the cultivation of ammonium-oxidizing bacteria (AOB) from the activated sludge, suppression of nitrite-oxidizing bacteria (NOB), investigation of in-situ growth kinetics of anammox bacteria (AnAOB), and the 50-day operation of the pilot-scale AnMBR-PN/A process for natural mainstream treatment. It is verified in the pilot-scale system for the first time that the in-situ free ammonia (FA) and free nitrous acid (FNA) exposure could effectively eliminate the Nitrospira (the NOB genus) while retaining the Nitosonomas (the AOB genus) community in the suspended sludge. NOB community rebounding was not detected even at the mainstream conditions with low nitrogen concentrations (Influent ammonium concentration=38±6 mg-NH4+-N/L) by intermittent aeration to control the system dissolved oxygen (DO) below 0.5 mg/L. The results of the mainstream treatment showed that the average effluent total nitrogen (TN) in the coupled process was generally lower than 10 mg-N/L, which meets the discharge limits of most prefectures in Japan. The investigated results of the in-situ anammox bacteria (AnAOB) growth kinetics suggested that the promoted start-up strategy of taking advantage of the warm months with higher mainstream temperature to achieve the rapid in-situ growth of the AnAOB is applicable in the investigated regions. From the perspective of the removal performance of the TN and organic substance, the AnMBR-PN/A process has great potential as the layouts of the carbon-neutral mainstream wastewater treatment plants.
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•A 1670-L mainstream IFAS type PN/A at decreasing temperatures of 25, 20 and 15°C.•The NLR was 0.21–0.24 kg-N/m3/d and the NRE was 65.9–75.4%.•Insufficient treatment capacity of AOB results in ...reduction of nitrogen removal at 15°C.•Candidatus Brocadia and Candidatus Kuenenia were main AnAOB and almost enriched on carriers.•NOB was suppressed by the strategy of intermittent aeration and low DO.
Partial nitritation-anammox (PN/A) is a promising deammonification process to develop energy-neutral wastewater treatment plants. However, the mainstream application of PN/A still faces the challenges of low nitrogen concentration and low temperatures, and has not been studied under a realistic condition of large-scale reactor (kiloliter level), real municipal wastewater (MWW) and seasonal temperatures. In this research, a pilot-scale one-stage PN/A, with integrated fixed-film activated sludge (IFAS) configuration, was operated to treat the real MWW pretreated by anaerobic membrane bioreactor. The removal efficiency of total nitrogen (TN) was 79.4%, 75.7% and 65.9% at 25, 20 and 15°C, corresponding to the effluent TN of 7.3, 9.7 and 12.0 mg/L, respectively. The suppression of ammonium-oxidizing bacteria (AOB) and anammox bacteria (AnAOB) occurred at lower temperatures, and the significant decrease in AOB treatment capacity was the reason for the poorer nitrogen removal at 15°C. Biomass retention and microbial segregation were successfully achieved. Specifically, Candidatus_Brocadia and Candidatus_Kuenenia were main AnAOB genera and mainly enriched on carriers, Nitrosomonas and uncultured f_Chitinophagaceae were main AOB genera and mainly distributed in suspended sludge and retained by sedimentation tank. Moreover, nitrite-oxidizing bacteria (NOB) were sufficiently suppressed by intermittent aeration and low dissolved oxygen, the presence of heterotrophic bacteria upgraded the PN/A to a simultaneous partial nitritation, anammox, denitrification, and COD oxidation (SNADCO) system, which improved the overall removal of TN and COD. The results of this investigation clearly evidence the strong feasibility of PN/A as a mainstream nitrogen removal process in temperate climates.
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A membrane-aerated biofilm reactor (MABR) provides bubbleless aeration and direct oxygen supply to a biofilm, achieving excellent aeration efficiency. Despite this advantage, research on membrane ...material is scarce. Here, we developed a composite membrane with high oxygen permeability and low vapor permeability with polystyrene elastomer (PS) as the intermediate non-porous layer sandwiched with porous polyethylene as the support layer. The oxygen transfer test demonstrated that the PS composite membrane provided 1.7 times higher oxygen transfer than the polyurethane (PU) composite membrane at an applied air pressure of 10 kPa. The membrane wettability test revealed that the PS composite membrane retained oxygen transfer capability. Two MABRs with the PU and PS composite hollow-fiber membranes, termed PU-MABR and PS-MABR, respectively, were continuously operated to treat organic carbon and nitrogen in synthetic wastewater. A higher carbon removal rate was obtained in PS-MABR 10.07 ± 0.76 g-C/(m2·day) than in PU-MABR 9.48 ± 0.83 g-C/(m2·day). The superior performance was likely because of the higher oxygen utilization rate by the biofilm on the PS membrane 33.41 ± 2.77 g-O2/(m2·day) than on the PU membrane 25.67 ± 7.36 g-O2/(m2·day). Moreover, PS-MABR allowed faster biofilm formation than PU-MABR. The new PS composite membrane resulted in effective oxygen supply, rapid startup, and high carbon removal by an MABR.
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•A new composite gas-permeable membrane using polystyrene was developed for MABRs.•The composite membrane exhibited high O2 and low H2O permeabilities.•Biofilm growth was faster on the polystyrene membrane than the polyurethane.•The biofilm showed high oxygen utilization and organic carbon removal rates.
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•Mass flows of C and N were redesigned by AnMBR-PN/A.•Removal efficiencies of COD and TN were 90.3%-95.1% and 75.0%-81.7%, respectively.•48.4%-63.1% of C was captured as CH4 and ...26.7%-39.7% of C was captured as sludge.•8.5%-16.1% of N was entrapped by membrane and 45.3%-58.1% of N was removed by PN/A.•AnMBR and PN/A mutually complement each other ensured excellent system performance.
A pilot-scale anaerobic membrane bioreactor (AnMBR) integrated with a one-stage partial nitritation-anammox (PN/A) reactor was operated for the treatment of municipal wastewater (MWW) at seasonal temperatures of 15–25 °C. The removal efficiencies of COD and total nitrogen (TN) were always > 90% and > 75% respectively. The methanogenesis and PN/A were identified as the primary removal pathways of COD and TN, respectively, and were suppressed at low temperatures. With the temperature dropped from 25 °C to 20 °C to 15 °C, the methane-accounted COD decreased from 63.1% to 59.6% to 48.4%, and the PN/A-accounted TN decreased from 58.1% to 51.7% to 45.3%. The AnMBR and PN/A mutually complement each other in this combined process, as the AnMBR removed 8.5%-16.1% of TN by sludge entrainment and the PN/A reactor removed 2.6%-3.4% of COD by denitrification and aerobic oxidation. These results highlighted the strong feasibility of applying the AnMBR-PN/A process to the treatment of MWW in temperate climate.
To summarize the pathophysiological analysis of idiopathic sudden sensorineural hearing loss (ISSNHL) by magnetic resonance imaging (MRI), focusing on the findings of high signal or endolymphatic ...hydrops (EH) in the inner ear.
We summarize the published studies of our research group regarding the pathophysiological analysis of ISSNHL on MRI and review related clinical articles that have reported significantly high signal or the existence of EH in ears with ISSNHL.
Pre-contrast high signal on MRI may indicate minor hemorrhage or increased permeability of surrounding vessels to the perilymph, whereas post-contrast high signal indicates breakdown of the blood-labyrinth barrier, in which irreversible changes would lead to poor prognosis. In some cases of ISSNHL, primary EH could be pre-existing and may be a risk factor for the onset of ISSNHL.
Analysis of ISSNHL by cutting-edge MRI evaluation could provide useful information for elucidating its pathophysiology and for predicting prognosis in this disease.
We summarize the presence of endolymphatic hydrops (EH) in otological disorders evaluated with magnetic resonance imaging (MRI) of temporal bones, and propose a classification of EH based on its ...pathological significance. A search of the literature published in English-language journals was performed using electronic databases, especially focusing on EH-related otological disorders. Clinical articles that contained the terms EH and contrast-MRI published from 2007 to the present, with relevant human temporal bone studies, were included. The following three main points are discussed based on the results in the relevant articles: i) otological disorders that present EH, ii) current grading for evaluation of EH on MRI, and iii) a proposed classification of EH based on its pathological significance. MRI evaluation revealed that EH exists extensively not only in ears with typical Meniere’s disease (MD), but also in those with various other otological disorders. The etiological classification of EH helps to summarize ideas for determining the pathophysiology of otological disorders, while a therapeutic classification provides clues to their management. MRI evaluations of EH have led to breakthroughs in investigations of EH in otological disorders. Precise grading for evaluation and clarification of EH on MRI based on its pathological significance could provide keys to elucidating the pathophysiology of EH-related otological disorders.
Primary laryngeal cryptococcosis is an extremely rare infection and presents with non-specific symptoms such as hoarseness or sore throat, resulting in delayed diagnosis. Here, we report the patient ...of a 56-year-old female patient with primary laryngeal cryptococcosis, who was being treated with oral and inhaled steroids for rheumatoid arthritis and bronchial asthma. The patient suffered from prolonged hoarseness and sore throat, and endoscopic biopsy was performed several times under local anesthesia, demonstrating only inflammatory cell infiltration. Considering the possibility of laryngeal malignancy, a third biopsy was performed by endoscopic laryngomicrosurgery under general anesthesia. Intraoperative frozen section revealed non-neoplastic laryngeal mucosa with erosion and severe inflammatory cell infiltration. However, we could not confirm the definite diagnosis of the lesion in the intraoperative consultation. Postoperative histopathological examination revealed a small number of yeast-type fungi and a definitive diagnosis was established by special stains including Alcian blue stain. Finally, the patient was diagnosed as primary laryngeal cryptococcosis. Daily oral administration of fluconazole (400 mg/day) was performed for 6 months according to the treatment protocol for pulmonary cryptococcosis. The symptoms gradually improved, and endoscopy revealed no recurrence 6 months post-treatment. Clinicians should consider the possibility of laryngeal cryptococcosis when severe inflammation is found in the larynx and discuss the disease history and pathological results with pathologists more closely.
High-amylose rice elicits a mild glycemic response; however, the effect of cooking condition on the glycemic response remains unclear. We aimed to investigate the effect of pressure-cooker cooking on ...postprandial glycemic response and eating qualities of the high-amylose rice “Koshinokaori”; and rice cooked in an electric rice cooker (KKE) was compared with that cooked in a pressure cooker (KKP). The intermediate-amylose rice “Koshihikari”, cooked in an electric rice cooker (KHE), was the reference. In ten healthy subjects, blood glucose variation was significantly lower after consumption of KKP (45 to 120 min) and KKE (60 to 120 min) compared to KHE. Incremental area under the curve after KKE and KKP intake was significantly lower than that after KHE intake. While the hardness of KKP was the highest, strength and stickiness were similar for all three samples. The sensory evaluation score of KKP was closer to that of KHE than KKE, indicating that KKP is a better choice for glycemic control.
The potential mechanism of augmented response on cervical vestibular evoked myogenic potential (cVEMP) testing and its decrease following treatment in a patient with Meniere's disease (MD) are ...discussed. Changes of static posturography and cVEMP testing before and after a glycerol drip in a 69-year-old man with unilateral MD, in which significant endolymphatic hydrops (EH) was confirmed on magnetic resonance imaging (MRI) on the diseased side, were evaluated. Values of total locus lengths, areas of postural sway, and their Romberg ratios were decreased after the glycerol drip. On cVEMP testing, the diseased ear demonstrated a 375% larger amplitude than the contralateral ear before treatment, but both ears showed almost the same responses after treatment. An augmented response on cVEMP testing and a decrease following treatment for MD reflect the diversity of clinical findings in MD. Responses on cVEMP testing may relate not only to the degree of EH, but also be due to abnormal acoustic energy absorbance transmitted into the saccule.
Two patients with auditory neuropathy spectrum disorder (ANSD) considered to be associated with Charcot-Marie-Tooth (CMT) are reported. In case 1, a 23-year-old man presented with progressive ...bilateral sensorineural hearing loss (SNHL) from 10 years of age and was diagnosed with ANSD. He was later diagnosed with CMT by neurological testing. In case 2, a 16-year-old girl, the younger sister of the patient in case 1, presented with progressive SNHL with similar auditory findings since 6 years of age as those of her brother. Both cases underwent bilateral cochlear implantation. In case 1, the maximum discrimination score improved to 45% 24 months after the first side of cochlear implantation from 5% before the surgery. In case 2, the score was 5% 10 months after cochlear implant (CI) surgery from 0% before the surgery. CI treatment for CMT patients has been considered difficult because of both failure in synchronization of nerve conduction due to demyelination and axonal failure of the auditory nerve. Though slower progress compared to the average subset of patients receiving CI was seen, significant improvement was gradually observed in the present patients after bilateral cochlear implantations. CI is thus a viable option for rehabilitation of SNHL in CMT patients.
