Comparison of Surgical Outcomes of Two New Techniques Complementing Robotic Single-Site Myomectomy: Coaxial Robotic Single-Site Myomectomy vs. Hybrid Robotic Single-Site Myomectomy.

BACKGROUND: This study aimed to compare surgical outcomes between two new robotic single-site myomectomy (RSSM)-complementary techniques: coaxial robotic single-site myomectomy (Coaxial-RSSM) and hybrid robotic single-site myomectomy (Hybrid-RSSM). METHODS: Medical records for 132 women undergoing Coaxial-RSSM and 150 undergoing Hybrid-RSSM, consecutively, were retrospectively reviewed. Patient characteristics and surgical outcomes were assessed and compared after propensity score matching (PSM). RESULTS: In the outcomes of PSM, the Coaxial-RSSM group showed significantly reduced blood loss (79.71 vs. 163.75 mL, p < 0.001) and reduced hospital duration (4.18 ± 0.62 vs. 4.63 ± 0.90) relative to the Hybrid-RSSM group. Conversely, Hybrid-RSSM allowed for a shorter operative time compared with Coaxial-RSSM (119.19 vs. 156.01 min, p = 0.007). No conversions to conventional laparoscopy or laparotomy or any need for the multi-site robotic approach occurred in either group. Postoperative complications, including ileus, fever, and wound dehiscence, showed no statistically significant differences between the two groups. CONCLUSIONS: Blood loss was lower with Coaxial-RSSM, and operative time was shorter for Hybrid-RSSM. A follow-up prospective study is warranted for more comprehensive comparison of surgical outcomes between the two techniques.

Myomectomy with ArtiSential fully articulating laparoscopic instruments: A prospective multicenter study.

BACKGROUND: ArtiSential, a class of innovative laparoscopic instrument, has been developed to overcome the limitations of conventional laparoscopic surgery by enabling free, 360°-unrestricted movement of the wrist joint, as in robotic surgery. OBJECTIVE: The aim of the present study was to describe the initial experiences with these devices in myomectomy and to report the surgical outcomes. METHODS: A total of 77 women undergoing laparoscopic or robotic myomectomy between January 2021 and June 2022 were included in this multicenter prospective study. The ArtiSential instruments used by the surgeons were those chosen according to their respective preferences. The baseline characteristics, surgical outcomes, trocar placement options, and operator survey results were scrutinized. RESULTS: The mean age of the patients was 39.9 ± 6.3, and the mean body mass index (BMI, calculated as weight in kilograms divided by the square of height in meters) was 22.4 ± 3.4 kg/m2 ; 46.8% of the patients underwent robotic surgery, while 53.2% underwent laparoscopic surgery. The number of removed myomas was 3.3 ± 3.0, the size of the largest myoma was 7.1 ± 2.3 cm, and the operative time was 130.0 ± 54.0 min. No transfusions or laparotomy conversions were required. Other than one case of ileus, there were no postoperative complications. In most cases, the instruments were inserted through the umbilicus trocar, and the fenestrated forceps, needle holder, and bipolar fenestrated forceps, in that order, were frequently employed. According to a surgeon survey, 29.9% moderately or strongly agreed that the ArtiSential devices utilized were more convenient than conventional laparoscopic instruments, while only 9.7% moderately or strongly agreed that they were more convenient than robotic instruments. CONCLUSIONS: Myomectomy as performed with an ArtiSential instrument seems to be feasible and safe. Further studies are necessary in order to comparatively assess the outcomes and potential benefits of ArtiSential, robotic, and conventional laparoscopic myomectomy.

Recurrence, Reoperation, Pregnancy Rates, and Risk Factors for Recurrence after Ovarian Endometrioma Surgery: Long-Term Follow-Up of 756 Women.

PURPOSE: The aims of this study were to evaluate the cumulative recurrence, reoperation, and pregnancy rates after ovarian endometrioma surgery at a single institution for more than a 5-year follow-up period. MATERIALS AND METHODS: This study was conducted as a retrospective chart review of patients with ovarian endometrioma who underwent surgery between January 2008 and March 2016. Study subjects included premenopausal women with at least 5 years of follow-up. Exclusion criteria were patients with stage I or II ovarian endometrioma, those who underwent hysterectomy or bilateral oophorectomy, and presence of residual ovarian lesions on the first postoperative ultrasonography at 3-6 months. Recurrence was defined as a cystic mass by ultrasonography. RESULTS: A total of 756 patients were recruited. The median follow-up duration was 85.5 months (interquartile range, 71-107 months). Recurrent endometrioma was detected in 27.9% patients, and reoperation was performed in 8.3% patients. Cumulative rates at 24, 36, 60, and 120 months were 5.8%, 8.7%, 15.5% and 37.6%, respectively, for recurrence and 0.1%, 0.5%, 2.9%, and 15.1%, respectively, for reoperation. After multivariable analysis, age ≤31 years [hazard ratio (HR)=2.108; 95% confidence interval (CI)=1.522-2.921; p<0.001], no subsequent pregnancy (HR=1.851; 95% CI=1.309-2.617; p<0.001), and postoperative hormonal treatment ≤15 months (HR=2.869; 95% CI=2.088-3.941; p<0.001) were significant risk factors for recurrent endometrioma. Among 315 patients who desired pregnancy, 54.0% were able to have a successful pregnancy and delivery. CONCLUSION: Considering that longer postoperative hormonal treatment is the sole modifiable factor for recurrent endometrioma, we recommend long-term hormonal treatment until subsequent pregnancy, especially in younger women.

Comparison of cesarean delivery outcome after robotic and laparoscopic myomectomy.

OBJECTIVE: The aim of this study was to determine whether robotic myomectomy (RM) resulted in any measurable clinical improvement over laparoscopic myomectomy (LM) in subsequent cesarean delivery. MATERIALS AND METHODS: The medical records of 273 patients who had undergone LM or RM followed by subsequent cesarean delivery for the period of September 2015 to December 2020 were retrospectively reviewed. The patients were divided into LM (n = 222) and RM (n = 51) groups. The cesarean delivery outcomes between the two groups were compared. RESULTS: RM had significantly more myomas removed (6.0 ± 4.8 vs. 3.6 ± 3.5, p < 0.001) and a larger size of largest myoma (7.7 ± 2.4 vs. 6.1 ± 2.4, p = 0.002) at myomectomy compared with LM. However, there were no significant differences in the groups' surgical characteristics at cesarean section, in their pregnancy complications, or in adhesion formation. CONCLUSIONS: Although more and larger myomas were removed in the RM group, RM showed similar cesarean delivery outcomes and adhesion formation to LM.

Robotic Single-Site Plus Two-Port Myomectomy versus Conventional Robotic Multi-Port Myomectomy: A Propensity Score Matching Analysis.

Background: Robotic single-site plus two port myomectomy (RSTM) was designed to reduce the number of incision sites while retaining the advantage of conventional robotic multi-port myomectomy (CRM). This study aimed to explicate RSTM and compare surgical outcomes between it and CRM. Methods: The medical records of 146 patients who had undergone RSTM and 173 who had undergone CRM were reviewed. The surgical outcomes between them were compared by propensity score matching (PSM) analysis. Results: The PSM analysis showed no statistically significant inter-group differences in patient characteristics. With regard to surgical outcomes, the RSTM group enjoyed shorter operative time (148.30 ± 44.8 vs. 162.3 ± 47.4 min, p = 0.011), less hemoglobin decrement (1.8 ± 0.9 vs. 2.3 ± 1.0 g/dL, p < 0.001), and shorter duration of hospital stay (5.4 ± 0.7 vs. 5.8 ± 0.7 days, p < 0.001). Conclusions: RSTM was associated with shorter operative time relative to CRM. Further prospective studies are needed in order to more fully investigate the advantages of RSTM.

Cumulative Recurrence Rate and Risk Factors for Recurrent Abdominal Wall Endometriosis after Surgical Treatment in a Single Institution.

PURPOSE: This study aimed to evaluate the cumulative recurrence rate and risk factors for recurrent abdominal wall endometriosis (AWE) after surgical treatment. MATERIALS AND METHODS: A retrospective cohort study was conducted at a single gynecological surgery center between January 2004 and December 2020. Patients who were surgically treated and followed up for at least 6 months after surgery were selected. RESULTS: Eighteen patients with pathologically diagnosed AWE were included in this study. The median follow-up duration was 22.5 months (range, 6-106). The median age was 37 years (range, 22-48), and 33.3% of the patients were nulliparous. Among the patients included in our study, 55.6% complained of a mass with cyclic pain, and 27.8% had a palpable mass. In addition, 22.2% of patients experienced recurrence with 17.5±9.7 months of mean time to recurrence. The cumulative recurrence rates at 24 and 60 months after surgical treatment of AWE were 23.8% and 39.1%, respectively. There were no statistically significant risk factors for the recurrence of AWE, including postoperative medical treatment. CONCLUSION: The recurrence rate of AWE appears to be correlated with the follow-up duration. There was no statistically significant risk factor for the recurrence of AWE. Unlike ovarian endometriosis, postoperative hormonal treatment does not seem to lower the recurrence of AWE. The findings of the current study may help healthcare providers in counselling and managing patients with AWE.

PAX2, PAX8, and PR are correlated with ovarian seromucinous borderline tumor with endometriosis.

BACKGROUND: Ovarian "seromucinous carcinoma" has been recently removed in 2020 5th Edition of WHO classification of Female Genital Tumors and is considered as a subtype of endometrioid carcinoma with mucinous differentiation, while "seromucinous borderline tumor" remains and exists as a distinct entity. Both diseases may be considered as no more same lineage. However, ovarian seromucinous borderline tumor (SMBT) is also one of the endometriosis-related neoplasm of ovary similar to endometrioid tumor, featuring that about 50% of ovarian SMBTs combine endometriosis. The present study was aimed to investigate whether the ovarian SMBTs are different in clinical features and molecular patterns, according to the presence of combined endometriosis. RESULTS: There were no statistical differences in clinical findings between two groups. There was also no significant difference in pregnancy outcomes and recurrence between two groups. In immunohistochemical patterns, there was a statistically significant difference in PAX2 and PAX8 expression between in ovarian SMBT with or without endometriosis (P = 0.016, P < 0.001). Only a few cases of ovarian SMBT with endometriosis showed expression of PAX2 and conversely, most of the cases showed expression of PAX8. PR positivity was more prominent in ovarian SMBT with endometriosis than without endometriosis (P = 0.018), although there was no difference in positive ER expression. There were no statistical differences in WT1, CK20 and CDX2 expressions between two groups. CONCLUSIONS: Ovarian SMBT with endometriosis did not clinically differ from that without endometriosis. However, the molecular patterns were different between two groups and ovarian SMBT with endometriosis is close to endometrioid tumor types unlike SMBT without endometriosis. Further, a direct comparison study between seromucinous borderline tumor and endometrioid borderline tumor is needed with a gene profiling study to prove their relationship.

Coaxial-Robotic Single-Site Myomectomy: Surgical Outcomes Compared with Robotic Single-Site Myomectomy by Propensity Score Matching Analysis.

BACKGROUND: The aim of this study was to introduce a coaxial-robotic single-site myomectomy (C-RSSM) technique to compensate for the shortcomings of robotic single-site myomectomy (RSSM) using semi-rigid instruments and to compare the surgical outcomes of C-RSSM and RSSM. METHODS: The medical records of 13 consecutive women who had undergone C-RSSM and 131 consecutive women who had undergone RSSM were retrospectively reviewed. Patient characteristics and surgical outcomes after propensity score matching were evaluated and compared between the two groups. RESULTS: According to the propensity score matching results, the C-RSSM group had a lower estimated blood loss (75.0 vs. 210.5 mL, p = 0.001) and a shorter operating time (101.0 vs. 146.1 min, p = 0.008) relative to the RSSM group. In RSSM, there was one case of conversion to conventional laparoscopy and four cases of conversion to the multi-site robotic approach. There was no case of conversion from C-RSSM to conventional laparoscopy or the multi-site robotic approach. CONCLUSIONS: C-RSSM was found to be associated with shorter operative time and lower estimated blood loss. However, further prospective studies are needed to confirm these advantages.

Effects of Using Barbed Suture in Myomectomy on Adhesion Formation and Adverse Pregnancy Outcome.

Background: There is still concern regarding postoperative adhesion formation and adverse effects on pregnancy outcomes caused by barbed suture (BS) after myomectomy. The aim of this study was to compare the postoperative adhesion and pregnancy outcomes between conventional suture (CS) and BS after minimally invasive myomectomy (MIM) by robotic myomectomy (RM) or laparoscopic myomectomy (LM). Methods: The medical records of 94 women who had undergone MIM with CS and 97 who had undergone MIM with BS and achieved pregnancy were reviewed. Postoperative adhesion was evaluated following cesarean section. Results: The number of removed myomas was greater (5.3 ± 4.6 vs. 3.5 ± 3.1, p = 0.001) and the size of the largest myoma was larger (7.0 ± 2.2 vs. 5.8 ± 2.7 cm, p = 0.001) in the BS group relative to the CS group. A total of 98.9% of patients in the CS group and 45.4% in the BS group had undergone LM (p < 0.001), while the others underwent RM. There was no significant difference in the presence of postoperative adhesion at cesarean section between the BS and CS groups (45.5 vs. 43.7%, p = 0.095). Additionally, there were no intergroup differences in pregnancy complications such as preterm labor, placenta previa, accrete or abruption. Note also that in our logistic regression analysis, the suture type (BS or CS) was excluded from the independent risk factors regarding postoperative adhesion formation. Conclusions: Our data indicated that the incidence of postoperative adhesion after MIM with BS was similar when compared with CS. Also it seems that the suture type does not have a significant effect on pregnancy outcomes.

Lead time on confirmatory test after abnormal Pap test in the COVID-19 era.

ABSTRACT: During the COVID-19 pandemic, there are concerns about medical delay, including confirmatory tests after screening for various cancers. We evaluated the lead time to a confirmatory test after an abnormal screening Papanicolaou (Pap) test in women before the COVID-19 period and during the COVID-19 period.The medical records of 1144 women who underwent colposcopy at a single institution located in Seoul after abnormal Pap results from January 2019 to December 2020 were reviewed. The lead time to colposcopy from the Pap test between 2019 and 2020 was compared; the adverse factors for a long lead time to colposcopy were also evaluated.Age, residence, institution, and the Pap results did not differ between women who underwent colposcopy in 2019 (n = 621) and 2020 (n = 523). The time to colposcopy from the Pap test was also not different. A higher number of women were diagnosed with high-grade dysplasia in 2020 and underwent excision procedures; however, the difference was not statistically significant. Instead, patients' residence, institution of the Pap test, and results of the Pap test were associated with a long lead time to colposcopy of >6 weeks.The lead time to colposcopy from the abnormal Pap test was not delayed in the COVID-19 era compared to before. However, regional factors could affect a long lead time.

Anti-Müllerian hormone level may predict successful pregnancy after adenomyomectomy in patients with infertility due to adenomyosis.

ABSTRACT: We aimed to determine clinical factors predicting successful pregnancy by comparing pregnancy failure and success groups after adenomyomectomy. Additionally, we analyzed fertility outcomes after adenomyomectomy.The medical records of 43 patients who had undergone adenomyomectomy and received in vitro fertilization treatment from 2017 to 2020 were retrospectively reviewed. Patients were divided into pregnancy failure (n = 28) and pregnancy success (n = 15) groups. Patients' demographic factors were evaluated and compared between the groups.The age of patients was higher (39.0 [32.0-45.0] vs. 37.0 [33.0-42.0] years, P = .006) whereas the level of anti-Müllerian hormone (anti-Müllerian hormone [AMH]; 0.54 [0.01-8.54] vs. 2.91 [0.34-7.92] ng/mL, P = .002) lower in the pregnancy failure group compared to the pregnancy success group. The operative time was longer (220.0 [68.0-440.0] vs. 175.0 [65.0-305.0] min, P = .048) while the estimated blood loss higher (750 [100-2500] vs. 500 [50-2000] mL, P = .016) in the pregnancy failure group compared to the pregnancy success group. No significant difference was observed in body mass index, symptoms, cancer antigen 125, preoperative uterine volume, or type of adenomyosis. In the multivariate analysis, age and AMH were significant predictive factors for successful pregnancy.Ovarian reserve (age and AMH) and disease severity might be predictive factors for successful pregnancy in patients who have undergone adenomyomectomy. Adenomyomectomy should be considered for women desiring pregnancy and having appropriate ovarian reserve. Our results would be beneficial for patients and clinicians before deciding on adenomyomectomy. Larger prospective studies are required to confirm our findings.

Fertility-sparing treatment in women with endometrial cancer.

Endometrial cancer (EC) in young women tends to be early-stage and low-grade; therefore, such cases have good prognoses. Fertility-sparing treatment with progestin is a potential alternative to definitive treatment (i.e., total hysterectomy, bilateral salpingo-oophorectomy, pelvic washing, and/or lymphadenectomy) for selected patients. However, no evidence-based consensus or guidelines yet exist, and this topic is subject to much debate. Generally, the ideal candidates for fertility-sparing treatment have been suggested to be young women with grade 1 endometrioid adenocarcinoma confined to the endometrium. Magnetic resonance imaging should be performed to rule out myometrial invasion and extrauterine disease before initiating fertility-sparing treatment. Although various fertility-sparing treatment methods exist, including the levonorgestrel-intrauterine system, metformin, gonadotropin-releasing hormone agonists, photodynamic therapy, and hysteroscopic resection, the most common method is high-dose oral progestin (medroxyprogesterone acetate at 500-600 mg daily or megestrol acetate at 160 mg daily). During treatment, re-evaluation of the endometrium with dilation and curettage at 3 months is recommended. Although no consensus exists regarding the ideal duration of maintenance treatment after achieving regression, it is reasonable to consider maintaining the progestin therapy until pregnancy with individualization. According to the literature, the ovarian stimulation drugs used for fertility treatments appear safe. Hysterectomy should be performed after childbearing, and hysterectomy without oophorectomy can also be considered for young women. The available evidence suggests that fertility-sparing treatment is effective and does not appear to worsen the prognosis. If an eligible patient strongly desires fertility despite the risk of recurrence, the clinician should consider fertility-sparing treatment with close follow-up.

The recurrence rate of ovarian endometrioma in women aged 40-49 years and impact of hormonal treatment after conservative surgery.

The aim of this study was to evaluate the rate of and risk factors for recurrence ovarian endometrioma after conservative surgery in patients aged 40-49 years. This retrospective, single-center study included 408 women between January 2008 and November 2018. All patients underwent ovarian cyst enucleation, were pathologically diagnosed with ovarian endometrioma and were followed up for ≥ 6 months. Recurrence was defined as a cystic mass with diameter ≥ 2 cm detected by sonography. Recurrence rate after conservative surgery and risk factor of recurrence were analyzed. The median follow-up duration after surgery was 32.0 ± 25.9 months (range 6-125 months). Ovarian endometrioma recurred in 34 (8.3%) of included women and median time to recurrence was 22.4 ± 18.2 months. The cumulative recurrences rate at 12, 24, 36, and 60 months were 3.7%, 6.7%, 11.1%, and 16.7%, respectively. Recurrence was correlated with multilocular cysts (p = 0.038), previous surgical history of ovarian endometrioma (p = 0.006) and salpingectomy (p = 0.043), but not use or duration of post-operative medication. In multivariate analysis, large cyst size (> 5.5 cm) was only risk factor for recurrence in this age group. Post-operative medication did not reduce disease recurrence rate, and thus may be administered for endometriosis-associated pain rather than to prevent recurrence in patients aged 40-49 years.

Atypical endometriosis is related to a higher recurrence rate.

OBJECTIVES: The aims of this study were to evaluate the clinical characteristics and recurrence rate of atypical endometriosis (AE)1 compared to typical endometriosis (TE) in addition to the malignant transformation rate among a large cohort. STUDY DESIGN: The medical records of 2681 patients who had undergone surgical treatment of ovarian endometrioma between January 2008 and September 2019 were retrospectively reviewed. The patients were divided into AE (n = 86) and TE (n = 2595) groups. Patients' characteristics and recurrence rates were evaluated and compared between the two groups. RESULTS: The mean size of ovarian cysts was significantly larger in the AE group (7.6 ± 3.5 cm vs 6.7 ± 3.3 cm, p = 0.01) and the proportion of nulliparous women was significantly lower in AE group (65.1 % vs 77.8 %, p = 0.008). Otherwise, there were no statistically significant differences in patient characteristics between the two groups. After Cox regression analyses with IPTW was adjusted, the risk factors for recurrent endometrioma were higher preoperative CA125 level >48 U/mL (hazard ratio [HR] = 2.741; 95 % confidence interval [CI] = 1.517-4.952; p < 0.001), multilocular cyst (HR = 1.909; 95 % CI = 1.128-3.230; p = 0.016), and atypical endometriosis (HR = 2.666; 95 % CI = 1.659-4.284; p < 0.001). The AE group displayed a significantly higher cumulative recurrence rate than the TE group (p = 0.0057, log-rank test). No patients were diagnosed with atypical endometriosis to malignant transformation during the follow-up periods. However, two typical endometriosis patients experienced borderline malignancy and serous carcinoma, respectively. CONCLUSION: Recurrence rates for AE were higher than for TE. Although the AE group included no patient with malignant transformation in this study, considering the higher recurrence as well as the possibility of malignant transformation, long-term close surveillance is warranted.

Comparison of operative time between robotic and laparoscopic myomectomy for removal of numerous myomas.

BACKGROUND: We hypothesized that the total operative time of robot myomectomy (RM) is shorter than that of laparoscopic myomectomy (LM) in cases where numerous myomas are removed, due to the faster suturing time of the robotic system. To verify this, we compared the surgical outcomes of RM vs LM for the number of myomas removed. METHODS: The medical records of 144 women underwent LM and 121 women underwent RM by a single surgeon were reviewed. RESULTS: The operative time did not statistically differ between the groups, even when the number of removed myomas was more than 12 (200.6 ± 48.2 vs 196.0 ± 48.4 minutes, P = .791). Note that in our logistic regression analysis, the operation type was excluded from the independent risk factors prolonging operative time. CONCLUSION: RM showed a similar operative time relative to LM regardless of the number of myomas removed (numerous or not).

Clinical management of abnormal Pap tests: differences between US and Korean guidelines.

Cervical cancer has been the most common gynecological cancer in Korea but has become a preventable disease with regular screening and proper vaccination. If regular screening is provided, cervical cancer does not progress to more than carcinoma in situ, due to its comparatively long precancerous duration (years to decades). In 2012, the American Society for Colposcopy and Cervical Pathology published guidelines to aid clinicians in managing women with abnormal Papanicolaou (Pap) tests, and they soon became the standard in the United States. Not long thereafter, the Korean Society of Gynecologic Oncology and the Korean Society for Cytopathology published practical guidelines to reflect the specific situation in Korea. The detailed screening guidelines and management options in the case of abnormal Pap test results are sometimes the same and sometimes different in the United States and Korean guidelines. In this article, we summarize the differences between the United States and Korean guidelines in order to facilitate physicians' proper management of abnormal Pap test results.

Robotic single-site myomectomy: A hybrid technique reducing operative time and blood loss.

BACKGROUND: To introduce a hybrid robotic single-site myomectomy (H-RSSM) technique that includes laparoscopic single-site myoma excision followed by robotic single-site suture and compare its surgical outcomes with those of conventional robotic single-site myomectomy (RSSM) using the da Vinci Si surgical system. METHODS: Medical records of 89 consecutive women who underwent H-RSSM and 131 consecutive women who underwent RSSM were retrospectively reviewed. Patients characteristics and surgical outcomes were evaluated and compared between two groups. RESULTS: The H-RSSM group had a significantly reduced operation time (98.7 ± 31.7 vs 141.4 ± 54.4 min, P < .001) and lower estimated blood loss (131.5 ± 78.1 vs 212.3 ± 189.8 mL, P < .001). Peritoneal adhesions were reported significantly more in the H-RSSM group than in the RSSM group (27.0% vs 9.2%, P < .001). CONCLUSION: H-RSSM was found to be associated with reduced operative time and lower estimated blood loss. However, further prospective studies are needed to clarify these advantages.

Membrane distillation combined with an anaerobic moving bed biofilm reactor for treating municipal wastewater.

A fermentative strategy with an anaerobic moving bed biofilm reactor (AMBBR) was used for the treatment of domestic wastewater. The feasibility of using a membrane separation technique for post-treatment of anaerobic bio-effluent was evaluated with emphasis on employing a membrane distillation (MD). Three different hydrophobic 0.2 µm membranes made of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and polypropylene (PP) were examined in this study. The initial permeate flux of the membranes ranged from 2.5 to 6.3 L m(-2) h(-1) when treating AMBBR effluent at a temperature difference between the feed and permeate streams of 20 °C, with the permeate flux increasing in the order PP < PVDF < PTFE. The permeate flux of the PTFE membrane gradually decreased to 84% of the initial flux after the 45 h run for distillation, while a flux decline in MD with either the PVDF or PP membrane was not found under the identical distillation conditions. During long-term distillation with the PVDF membrane, total phosphorus was completely rejected and >98% rejection of dissolved organic carbon was also achieved. The characterization of wastewater effluent organic matter (EfOM) using an innovative suite of analytical tools verified that almost all of the EfOM was rejected via the PVDF MD treatment.

Membrane fouling control using a rotary disk in a submerged anaerobic membrane sponge bioreactor.

Despite significant research efforts over the last few decades, membrane fouling in anaerobic membrane bioreactors (AnMBRs) remains an unsolved problem that increases the overall operational costs and obstructs the industrial applications. Herein, we developed a method for effectively controlling the membrane fouling in a sponge-submerged AnMBRs using an anaerobic rotary disk MBR (ARMBR). The disk rotation led the effective collision between the sponge and membrane surface; thus successfully enhanced the membrane permeability in the ARMBR. The effect of the disk rotational speed and sponge volume fraction on the membrane permeability and the relationship between the water flow direction and membrane permeability were investigated. The long-term feasibility was tested over 100days of synthetic wastewater treatment. As a result, stable and economical performance was observed without membrane replacement and washing. The proposed integrated rotary disk-supporting media appears to be a feasible and even beneficial option in the AnMBR technology.