Coupling high-rate activated sludge process with aerobic granular sludge process for sustainable municipal wastewater treatment

Achieving a neutral/positive energy balance without compromising discharge standards is one of the main goals of wastewater treatment plants (WWTPs) in terms of sustainability. Aerobic granular sludge (AGS) technology promises high treatment performance with low energy and footprint requirement. In this study, high-rate activated sludge (HRAS) process was coupled to AGS process as an energy-efficient pre-treatment option in order to increase energy recovery from municipal wastewater and decrease the particulate matter load of AGS process. Three different feeding strategies were applied throughout the study. AGS system was fed with raw municipal wastewater, with the effluent of HRAS process, and with the mixture of the effluent of HRAS process and raw municipal wastewater at Stage 1, Stage 2 and Stage 3, respectively. Total suspended solids (TSS), chemical oxygen demand (COD), ammonia nitrogen (NH₄⁺-N), and total phosphorus (TP) concentrations in the effluent were less than 10 mg/L, 60 mg/L, 0.4 mg/L, and 1.3 mg/L respectively at all stages. Fluctuations were observed in the denitrification performance due to changes in the influent COD/total nitrogen (TN) ratio. This study showed that coupling HRAS process with AGS process by feeding the AGS process with the mixture of HRAS process effluent and raw municipal wastewater could be an appropriate option for both increasing the energy recovery potential of WWTPs and enabling high effluent quality.

Impact of primary sedimentation on granulation and treatment performance of municipal wastewater by aerobic granular sludge process

Aerobic granules contain microorganisms that are responsible for carbon, nitrogen, and phosphorus removal in aerobic granular sludge (AGS) process in which aerobic/anoxic/anaerobic layers (from surface to core) occur in a single granule. Optimizing the aerobic granular sludge (AGS) process for granulation and efficient nutrient removal can be challenging. The aim of this study was to examine the impact of settling prior to AGS process on granulation and treatment performance of the process. For this purpose, synthetic wastewater mimicking municipal wastewater was fed directly (Stage 1), and after primary sedimentation (Stage 2) to a laboratory-scale AGS system. In full-scale wastewater treatment plants, primary sedimentation is used to remove particulate organic matter and produce primary sludge which is sent to anaerobic digesters to produce biogas. Performances obtained in both stages were compared in terms of treatment efficiency, granule settling behavior, and granule morphology. Granulation was achieved in both stages with more than 92% chemical oxygen demand (COD) removal efficiencies in each stage. High nutrient removal was obtained in Stage 1 since anaerobic phase was long enough (i.e., 50 min) to hydrolyze particulate matter to become available for PAOs. Primary sedimentation caused a decrease in influent organic load and COD/N ratio, as a result, low nitrogen and phosphorus removal efficiencies were observed in Stage 2 compared to Stage 1. With this study, the effect of the primary sedimentation on the biological removal performance of AGS process was revealed. COD requirement for nutrient removal in AGS systems should be assessed by considering energy generation via biogas production from primary sedimentation sludge.

Removal of micropollutants from municipal wastewater by membrane bioreactors: Conventional membrane versus dynamic membrane

In this study, fate of micropollutants was investigated in a membrane bioreactor (MBR) having dynamic membrane (DM) and ultrafiltration (UF) membrane for the treatment of raw municipal wastewater. Removal efficiencies of different micropollutants including sulfamethoxazole, ciprofloxacin, trimethoprim, caffeine and acetaminophen were assessed. A commercial hollow fiber UF membrane was used in parallel with a DM that was formed on a low-cost hollow fiber support material, made of polyester. MBR was operated at a flux of 10 L/m²·h. High total suspended solids (>99%) and chemical oxygen demand (>91%) removal efficiencies were achieved with each membrane. Besides, high removal efficiencies of micropollutants (>68.3->99.7%) were achieved. Morphological analyses were conducted for each membrane in order to get insight to the cake (dynamic) layer that was accumulated on the membrane. DM technology provides an effective alternative to the conventional membrane systems for micropollutant removal from municipal wastewater.

The First Case of Multisystem Inflammatory Syndrome in Children Successfully Treated with Combined Therapies Including Extracorporeal Membrane Oxygenation and Plasmapheresis

Multisystem inflammatory syndrome in children (MIS-C) is a severe disease that can lead to death. There is no definitive treatment for MIS-C yet. It has been reported that intravenous immunoglobulin, intravenous methylprednisolone, fluid supplements, antibiotics, inotropics, extracorporeal membrane oxygenation (ECMO), plasmapheresis, biological therapy, and anticoagulation therapy can be used for treatment. In this article, we presented an 8-year-old girl child patient who survived due to timely administered ECMO and combined therapies including plasmapheresis without any sequela despite her life-threatening condition due to MIS-C.

Limited upper mini-sternotomy approach for closed heart surgery in the newborns and infants

BACKGROUND

The mini-sternotomy has become a common approach of choice for a wide range of congenital defects requiring minimally invasive surgery. Here, we aimed to present closed heart surgery results via limited upper mini-sternotomy in the newborn and infants.

METHODS

A total of 46 infants who underwent pulmonary artery banding, patent ductus arteriosus ligation, and aortopexy via limited upper mini-sternotomy between December 2017 and October 2020 were enrolled. Patients included 26 males and 20 females with ages ranging from 2 days to 12 months (median age 3.25 ± 0.9 months). The weight ranged from 0.7 kg to 8 kg (median weight 3.6 ± 1.8 kg). These patients were evaluated retrospectively in terms of clinical, preoperative, intraoperative, and postoperative parameters.

RESULTS

Closed heart surgery procedures were corrected successfully without adverse events intraoperatively. The median operation time was 32 min (32 ± 7 min). The limited upper mini-sternotomy was performed on 46 patients, including the pulmonary banding (18 patients), PDA ligation (16 patients), and aortopexy (12 patients). No patients required conversion to full sternotomy or to extend the incision. Re-intervention to adjust the tightness of the band was required in 1 patient. There were 4 cases of mortality (8.6%). All four death cases had comorbidity and low birth weight (2500 g or less).

CONCLUSION

Limited upper mini-sternotomy is a technically feasible, safe, and effective approach that providing an adequately surgical view in closed heart surgery to reduce the invasiveness of the closed heart surgical repair via median sternotomy or thoracotomy approach.

Bedside surgical ligation of the patent ductus arteriosus in very-low-birth-weight premature infants: Limited upper ministernotomy as an alternative approach

BACKGROUND

Patent ductus arteriosus (PDA) is an important cause of morbidity and mortality, especially in very-low-birth-weight infants. The aim of the present study was to evaluate the outcomes of bedside surgical ligation of PDA via limited upper ministernotomy as an alternative approach to thoracotomy.

MATERIALS AND METHODS

A total of 23 low-birth-weight premature infants, who underwent bedside ligation of PDA in the neonatal intensive care unit between January 2017 and April 2020, were enrolled. The patients were divided into two groups: those with thoracotomy (n = 13) and those with limited upper ministernotomy (n = 10). These patients were evaluated retrospectively in terms of clinical and preoperative, intraoperative, postoperative parameters between the groups.

RESULTS

Mean birth weight was 1059 ± 275 g in the thoracotomy group and 1035 ± 285 g in the ministernotomy group. There was no statistically significant difference in the age at surgery, weight at surgery, preoperative mechanical ventilation (MV) support, inotropic score onset of surgery, and total procedure time between the groups. There was a statistically significant difference in the hospital length of stay, postoperative MV time, and complications in the intensive care unit in favor of the ministernotomy group (p = .04, p = .03, p = .034, respectively). The study showed no statistically significant difference in the mortality rate between the two groups (two patients in the thoracotomy group and one patient in the ministernotomy group).

CONCLUSION

The limited upper ministernotomy is an anatomically and technically feasible alternative to classical left posterolateral thoracotomy for bedside surgical PDA ligation.

Levoatrial Cardinal Vein: Occluder Embolization and Complication Management

In rare cases, levoatrial cardinal vein may occur as an isolated condition without additional congenital anomalies. Depending on the direction and flow of the shunt, this pathology may produce symptoms; alternatively, it may be asymptomatic, as in the case presented in this study. In asymptomatic cases, complications, such as paradoxical embolism and brain abscess, can arise later. In the 11-year-old patient whose case is presented here, the levoatrial cardinal vein was asymptomatic and incidentally detected. The percutaneous closure method was applied first. However, by 16 hours after the procedure, the occluder device had embolized to the iliac artery. Emergency surgery was performed; first, the occluder device was removed, and levoatrial cardinal vein ligation was then performed via a mini-thoracotomy. The symptoms, diagnosis, and treatment modalities of isolated levoatrial cardinal vein are discussed in the context of this case described herein.

Transversus Thoracic Muscle Plane Block for Analgesia After Pediatric Cardiac Surgery

OBJECTIVE

The objective of this study was to assess the effectiveness of transversus thoracic muscle plane block (TTPB) as a novel technique for postoperative analgesia in pediatric cardiac surgery.

DESIGN

A retrospective study.

SETTING

A tertiary care teaching hospital.

PARTICIPANTS

Children who underwent congenital heart surgery through median sternotomy between January 2018 and March 2019.

INTERVENTIONS

Bilateral ultrasound-guided TTPB was performed as a single-shot technique before the sternal incision. A total dose of bupivacaine 0.25% (0.5 ml/kg) was injected between the fourth and fifth ribs just lateral to the sternum. Patients who received TTPB were designated as the TTPB group, and the other group was named the non-TTPB group MEASUREMENTS AND MAIN RESULTS: Thirty-three patients underwent intraoperative bilateral TTPB before the sternal incision and 37 did not. The groups were comparable as for demographic and intraoperative clinical characteristics. Pain scores were significantly lower in the TTPB group compared with the non-TTPB group (p < 0.001). Intraoperatively, non-TTPB patients received significantly higher doses of fentanyl (p < 0.001). Moreover, the total fentanyl dose during a 24-hour period was also higher in the non-TTPB group (p < 0.001). The time to extubation was significantly lower in the TTPB group than in the non-TTPB group (p < 0.001).

CONCLUSIONS

TTPB appeared to be an effective technique for postoperative analgesia in pediatric patients undergoing cardiac surgery using a median sternotomy approach.

Randomized controlled trial of 8 weeks' vs 12 weeks' interval between neoadjuvant chemoradiotherapy and surgery for locally advanced rectal cancer

AIM

The aim was to compare the pathological complete response (pCR) rate at 8 compared to 12 weeks' interval between completion of neoadjuvant chemoradiotherapy (CRT) and surgery in patients with locally advanced rectal cancer.

METHOD

This was a randomized trial which included a total of 330 patients from two institutions. Patients with locally advanced (T3-4N0M0, TxN+M0) rectal cancer were randomized into 8- and 12-week interval groups. All the patients received long-course CRT (45 Gy in 1.8 Gy fractions and concomitant oral capecitabine or 5-fluorouracil infusion). Surgery was performed at either 8 or 12 weeks after CRT. The primary end-point was pCR. Secondary end-points were sphincter preservation, postoperative morbidity and mortality.

RESULTS

Two-hundred and fifty-two patients (n = 125 in the 8-week group, n = 127 in the 12-week group) were included. Demographic and clinical characteristics were similar between groups. The overall pCR rate was 17.9% (n = 45): 12% (n = 15) in the 8-week group and 23.6% (n = 30) in the 12-week group (P = 0.021). Sphincter-preserving surgery was performed in 107 (85.6%) patients which was significantly higher than the 94 (74%) patients in the 12-week group (P = 0.016). Postoperative mortality was seen in three (1.2%) patients overall and was not different between groups (1.6% in 8 weeks vs 0.8% in 12 weeks, P = 0.494). Groups were similar in anastomotic leak (10.8% in 8 weeks vs 4.5% in 12 weeks, P = 0.088) and morbidity (30.4% in 8 weeks and 20.1% in 12 weeks, P = 0.083).

CONCLUSION

Extending the interval between CRT and surgery from 8 to 12 weeks resulted in a 2-fold increase in pCR rate without any difference in mortality and morbidity.

Comparative evaluation of ultrafiltration and dynamic membranes in an aerobic membrane bioreactor for municipal wastewater treatment

This study investigated the applicability of self-forming hollow fiber dynamic membrane (DM) as a low-cost alternative to ultrafiltration (UF) membrane. A hollow fiber polyester fabric was used as a support material to form the DM layer. Submerged DM and UF hollow fiber membrane were placed in the same reactor in order to compare the treatment and filtration performance of each membrane. Morphological analyses were also carried out for DM surface. The system was operated continuously at a flux of 5 L/m² h for 85 days. High COD removal efficiency and total suspended solids (TSS) rejection were achieved by the DM. Transmembrane pressure (TMP) of the DM was higher in comparison to the UF membrane, which was related with the formation of cake layer in DM. DM technology can be used as an alternative to UF membrane for municipal wastewater treatment.

Surgical Site Infection: Re-assessment of the Risk Factors

BACKGROUND

Surgical site infection (SSI) is a well-known complication of general surgery. Although overall SSI rate is relatively low, it is the most common nosocomial infection. SSI adversely affects patient outcomes and healthcare costs.

METHODS

Patients who underwent general surgical procedures between 2003 and 2009 were included in the study. SSI diagnosed based on the National Nosocomial Infection Surveillance System (NNIS) criteria. Patients were classified into two groups: SSI (+) and SSI (-). Patient demographics, co-morbidities, procedural details, and SSI type and treatment were evaluated. Multivariate analysis was performed to determine independent risk factors of SSI.

RESULTS

In total, 4690 patients were included. Overall SSI rate was 4.09% (192/ 4690). Colorectal surgery was associated with the highest SSI rate (9.43%) followed by pilonidal sinus (8.79%), upper gastrointestinal (GI) (8.09%), hepatobiliary (6.68%), hernia (0.78%), and breast-thyroid (0.3%) surgery. Procedure type (pilonidal sinus, colorectal, hepatobiliary and upper GI surgery), prolonged preoperative hospital stay, higher ASA score, emergency surgery, dirty- infected wound class, experienced surgeon, prolonged operating time, presence of surgical drains, and intraoperative transfusion were determined as independent risk factors of SSI (p 0.05).

CONCLUSION

Most of the determined risk factors were surgeon and procedure related. Reduced SSI rate and better outcomes can be achieved by controlling modifiable risk factors.

Endoscopic Removal of Duodenal Perforating Fishbone - A Case Report

BACKGROUND

Accidental ingestion of foreign bodies is common in clinical practice. While perforation of the ileum and jejunum due to the ingested foreign body is common, duodenal perforation is rare. In this report, our experience with this rare entity is shared.

CASE REPORT

Here we present a 31-year-old patient with gastrointestinal tract perforation at the second part of the duodenum due to an ingested fishbone. The patient was admitted to the emergency room with abdominal pain. Right upper quadrant tenderness was detected at physical examination, and leukocytosis on the laboratory test results. Ultra-sonography was not diagnostic, however, computerized tomo-graphy showed an ingested foreign body in the second part of the duodenum. A fishbone perforating the duodenum was retrieved by endoscopy. The patient was managed non-operatively, and discharged without any problems on the third day after endoscopy.

CONCLUSION

Endoscopic removal and non-operative management may be feasible in carefully selected patients with duodenal perforated fishbone ingestion.

Right Anterolateral Thoracotomy in the Repair of Atrial Septal Defect: Effect on Breast Development

BACKGROUND AND AIM

The aim of this study was to assess the cosmetic results and the impact on the breast development of a right anterolateral thoracotomy (RALT) in pre-pubertal children who underwent RALT for correction of atrial septal defects.

METHODS

From December 2002 to July 2010, 25 female patients with a mean age of 8.5 ± 1.3 years underwent repair of atrial septal defects with a right anterolateral thoracotomy. Breast symmetry was described by a clinical index. The degree of scoliosis was measured by clinical examination. The subjective evaluation in breast asymetry, size, and shape was assessed by a survey obtained by the patients.

RESULTS

There was no intraoperative or postoperative complication or late mortality in the thoracotomy approach or in the long-term follow-up (7.5 ± 2.2 years). According to the survey, breast asymmetry and differences between both breast size or shape were found in 15 (60%) and seven (28%) patients, respectively. One patient (4%) complained of a keloid scar. Mild sensitive skin deficit in the mammary area was determined in four patients (16%). According to the objective assessment, breast asymmetry was found 12 patients (48%) with index 1 and 13 patients (52%) with index 2.

CONCLUSION

Although it is safe, the RALT is associated with the potential to effect unilateral breast development.

Selective management of high risk patients with an ascending aortic dilatation during aortic valve replacement

BACKGROUND

The ascending aortic dilatation secondary to aortic valve disease may be a risk for rupture or dissection unless it is not corrected with a graft replacement during valve surgery. This additional procedure requires prolonged operation time that can be harmful for the critical patient. External reinforcement of diseased aorta is an old but simple method with debated long term results, providing brief duration and lower complication rate of the aneurysm operation for critically ill patients whose life expectancy is poor.

METHODS

Twenty-two patients underwent aortic valve replacement and external aortic wrapping procedure in our clinic. All of the patients had severe associated risk factors to complicate the classical aortic graft replacement procedure. In this prospective clinical study, the follow-up period of the patients is 79.91 patient-years.

RESULTS

There was no operative mortality. The average hospital stay was 8.6+/-2.6 days. There was no late death or cardiac morbidity. All of the patients were in NYHA Class 1 at postoperative 3rd month and thereafter. In CT scans the mean preoperative ascending aortic diameter was 5.12+/-0.38 cm while the mean diameter at 3rd month postoperatively was 3.19+/-0.25 cm. The reduction in diameter showed a significant difference (p<0.0001). The time related changes in luminal diameters showed some enlargement within the first year of the operation (p=0.03) that remained the same thereafter.

CONCLUSIONS

The early results and 4 years follow-up suggest that the technique can be regarded as safe and effective in selected high risk patients.

Sternal cyanoacrylate gluing in mediastinitis. Effects on infection, stability and bone healing

BACKGROUND

It is crucial to determine stability, histocompatibility and antibacterial properties of the cyanoacrylate used for sternal fixation.

METHODS

Clinical study: in 17 cases of mediastinitis, debridement and rewiring the sternum, was applied as the treatment method (Group I). Eighteen cases of mediastinitis were treated with the same method added sternal cyanoacrylate gluing (Group II). A comparative study was done; the follow-up period was 36.7+/-4 and 18.5+/-6.9 months in Group I and II, respectively. Animal study: in 10 rats, upper sternotomy was done and the sternal bone was contaminated. Direct wound closure was done in 4 rats (Group A), in 6 animals, wounds were closed after applying cyanoacrylate in sternal split (Group B). In this prospective study, all rats alive were sacrificed at the 3rd and 8th weeks and sternums were examined histologically.

RESULTS

Clinical study: in Group I, 6 patients required additional interventions due to recurrent sternal detachment and osteomyelitis (35.3%). In Group II neither osteomyelitis nor sternal detachment occurred, 3 patients required re-intervention related to cyanoacrylate histotoxicity. Hospital stay was higher in Group I than Group II (24.06+/-4.7 vs 14.16+/-3.98 days, respectively). Experimental study: all of the animals in Group A died of sepsis. In Group B all rats survived the procedure. At the 3rd week histologic evaluations showed that cyanoacrylate was not degraded, and no infection or foreign body reaction was observed. At the 8th week histologic examination showed that cyanoacrylate was completely degraded and replaced by connective tissue.

CONCLUSIONS

Cyanoacrylate is effective in diminishing sternal wound complications and related cost and hospital stay of mediastinitis.

Mechanical versus biological valve prosthesis in the mitral position: a 10-year follow up of St. Jude Medical and Biocor valves

BACKGROUND AND AIM OF THE STUDY

During the past 30 years, the development of mechanical and biological valves has led to major improvements in patient survival. Here, we present long-term results obtained with both types of prosthesis.

METHODS

At our institution, between 1985 and 1989, 158 patients received a Biocor porcine bioprosthesis, and 100 patients a St. Jude Medical (SJM) mechanical valve. Preoperatively, mean age, male:female ratio, NYHA functional class and pathology of mitral valve disease were similar in both groups.

RESULTS

The 30-day mortality was 4.4% in the Biocor group and 4% in the SJM group, the major cause being congestive heart failure. Late mortality was 17.9% and 15.6% respectively in the two groups, but valve-related mortality was very low in both (1.3% versus 4.2%). Ten-year survival was similar in each group (77.8+/-3.4% versus 81.0+/-3.9%; p = 0.538). Ten-year freedom from anticoagulant-related hemorrhage was higher with Biocor prostheses (99.3+/-0.7% versus 90.9+/-3.1%; p = 0.007). Valve thrombosis was seen only in the SJM group, and structural valve degeneration (SVD) only in the Biocor group. Ten-year freedom from reoperation was lower in the Biocor group (84.9+/-3.2% versus 92.2+/-2.8%; p = 0.206). The significant causes of reoperation were SVD in the Biocor group and valve thrombosis in the SJM group. Freedom from prosthetic valve endocarditis was similar in both groups (96.3+/-1.6% versus 95.5+/-2.2%).

CONCLUSION

As no difference was seen in survival and reoperation rates between patients receiving either bioprostheses or mechanical valves, the valve used will depend on the surgeon's choice and the type of patient, notably elderly patients who are intolerant of anticoagulation, and young women wishing to have children.

Surgical repair in ruptured congenital sinus of Valsalva aneurysms: a 13-year experience

BACKGROUND AND AIM OF THE STUDY

Rupture of congenital sinus of Valsalva aneurysm is a rare cardiac malformation that usually causes reduced cardiac performance.

METHODS

Twenty patients (mean age 28.3 +/- 10.7 years; range: 14 to 55 years) with rupture of congenital sinus of Valsalva aneurysm were operated on at our institution between January 1985 and March 1999. The origin of the ruptured aneurysms was the right coronary sinus in 18 patients (90%) and the non-coronary sinus in two (10%). No ruptures were observed originating from the left coronary sinus. The aneurysms ruptured into the right ventricle in 14 patients (70%), into the right atrium in five (25%), and into the left ventricle in one patient (5%). Subarterial ventricular septal defect (VSD) was the most common associated defect (30%), and aortic insufficiency the second (20%). No correlation was found between subarterial VSDs and aortic insufficiency (p > 0.05). To achieve repair, the aorta and cavity into which the aneurysm had ruptured were opened. The aneurysmal sac was excised and the defect closed with a patch in 18 patients, and without patch in two.

RESULTS

One patient died in hospital (mortality rate 5%); no late mortality was observed. Surviving patients were followed up for 4.4 +/- 3.3 years (range: 1 to 13 years). The actuarial survival rate was 95% at 12.35 years. Recurrence of fistula was observed in one patient (5%) in whom the ruptured aneurysm had been closed by primary suture without the use of a patch. At 12.35 years, the actuarial freedom from recurrence of fistula was 94.74% for all survivors, and 100% for patients with patch closure. No late complications have been observed.

CONCLUSIONS

Following diagnosis of ruptured sinus of Valsalva aneurysm, surgical repair is the treatment of choice. Surgery performed as rapidly as possible after diagnosis in general leads to an excellent outcome.

Gastrocolic fistula due to gastric cancer (a case report)

Gastrocolic fistula originating from gastric cancer is a rare complication. Allison [1] collected 233 reports on patients with fistulas due to malignant tumours of the stomach and colon. In this article, a patient suffering from gastrocolic fistula as a complication of gastric carcinoma is presented.