Publications by authors named "D M Santoro"

486 Publications

Digital solutions for continued operation of WRRFs during pandemics and other interruptions.

Water Environ Res 2021 Jul 28. Epub 2021 Jul 28.

Jacobs, Englewood, CO, USA.

This paper includes survey results from seventeen (17) full-scale water resource recovery facilities (WRRFs) to explore their technical, operational, maintenance and management related challenges during COVID-19. Based on the survey results, limited monitoring and maintenance of instrumentation and sensors are among the critical factors during the pandemic which resulted in poor data quality in several WRRFs. Due to lockdown of cities and countries, most of the facilities observed interruptions of chemical supply frequency which impacted the treatment process involving chemical additions. Some plants observed influent flow reduction and illicit discharges from industrial wastewater which eventually affected the biological treatment processes. Delays in equipment maintenance also increased the operational and maintenance cost. Most of the plants reported that new set of personnel management rules during pandemic created difficulties in scheduling operator's shifts which directly hampered the plant operations. All the plant operators mentioned that automation, instrumentation, and sensor applications could help plant operations more efficiently while working remotely during pandemic. To handle emergency circumstances including pandemic, this paper also highlights resources and critical factors for emergency responses, preparedness, resiliency, and mitigation that can be adopted by WRRFs.
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http://dx.doi.org/10.1002/wer.1615DOI Listing
July 2021

Biological nutrient removal enhancement using fermented primary and rotating belt filter biosolids.

Sci Total Environ 2021 Jul 10;796:148947. Epub 2021 Jul 10.

Department of Civil and Environmental Engineering, Western University, London, ON N6A 5B9, Canada; Department of Chemical and Biochemical Engineering, Western University, London, ON N6A 5B9, Canada.

This research compared the impact of two primary treatment options (i.e. primary clarification and rotating belt filtration (RBF)) on biological nutrients removal (BNR) process, using sludge fermentation liquid (SFL) as a carbon source. The liquid fraction of both fermented primary and RBF sludges comparably enhanced BNR. Despite the significant contribution of the unpurified SFL to the sharp increase in nutrient levels; i.e. 47%-64% (primary effluent; PE), and 45%-53% (RBF) of the soluble nitrogen and phosphorus loads; readily biodegradable COD and volatile fatty acids (VFAs) fractions of the combined feed increased significantly (2.5-6.1 times), compared to the original feed by additional SFL. Removal efficiencies in the reactors reached 57% (total nitrogen) and 92% (total phosphorus) after addition of SFL. Effluent nitrogen and phosphorus of the two reactors were close in the range of 15 ± 6 mg N/L, and 0.5 ± 0.3 mg P/L, respectively. Kinetics studies showed denitrification rates of 1.3, and 1.13 kg NO-N/m.d for primary effluent and RBF effluent-fed reactors, respectively. Phosphorus release rates were 11.7 and 9.7 mg PO-P/g VSS.h, for primary, and RBF effluents, respectively; showing 20%-22% lower rates in the RBF SFL. Incorporating experimental data into a plant-wide model for a 100 MLD facility receiving typical medium strength wastewater, showed that although primary treatment enhanced the biogas production by 96% (primary clarification) and 62% (RBF) trains; combined fermentation and anaerobic digestion was effective to enhance the biogas production by 59% on average, compared to the base scenario without primary treatment. Additionally, if primary clarification exists, then the addition of fermentation results in additional revenue of C$1890/d in the plant, considering additional revenue of C$2230/d due to VFA generation in contrast to only C$340/d loss due to the reduced methane production.
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http://dx.doi.org/10.1016/j.scitotenv.2021.148947DOI Listing
July 2021

Mechanistic modeling of peracetic acid wastewater disinfection using computational fluid dynamics: Integrating solids settling with microbial inactivation kinetics.

Water Res 2021 Jun 11;201:117355. Epub 2021 Jun 11.

US Peroxide Technologies, 1375 Peachtree St. NE, Suite 300 N., Atlanta, GA, USA. Electronic address:

While the impact of suspended solids on chemical disinfection kinetics has been widely recognized, a detailed modeling framework for assessing their contribution on disinfection efficiency in municipal contact tanks is yet unavailable. In this paper, we conducted experimental and modeling studies to mechanistically describe the interplay between suspended solids (not removed by gravity settling in secondary clarifiers) and disinfection performance of an emerging disinfectant, peracetic acid, operated in a municipal contact tank. Specifically, we developed an integrated computational fluid dynamics (CFD) model to simultaneously predict the fate and transport of suspended solids, Escherichia coli and peracetic acid in a hypothetical reactor using an exposure-based (i.e., CT-based) inactivation rate expression. The integrated CFD model, calibrated against laboratory data, was used to gain insights on the vertical distribution and local PAA decay effect associated with solids settling and their impact on disinfectant decay and microbial inactivation. Results indicated that: (a) solids settling in contact tanks is a significant phenomenon that cannot be neglected, which can substantially impact disinfection efficiency under low flow conditions; (b) vertical solids distribution and stratification in contact tanks can strongly affect Escherichia coli inactivation by peracetic acid, as highlighted by the CFD modeling studies; (c) Escherichia coli settling is experimentally measurable, and strongly correlated with solids settling. These phenomena can be successfully integrated into a CFD model to obtain a comprehensive description of the PAA disinfection process in presence of changes in secondary effluent quality and flow, a situation typically encountered in municipal contact tanks operated in full scale wastewater treatment plants.
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http://dx.doi.org/10.1016/j.watres.2021.117355DOI Listing
June 2021

A clinical retrospective study of Caparinia tripilis (Psoroptidae) mite dermatitis in pet African pygmy hedgehogs (Ateletrix albiventris) in southern Italy.

Vet Dermatol 2021 Jun 27. Epub 2021 Jun 27.

Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, 2015 SW 16th Ave, Gainesville, FL, 32610, USA.

Background: Caparinia tripilis is a common ectoparasitic mite affecting African pygmy hedgehogs, and is associated with pruritus and self-trauma. There have been no published surveys on the prevalence of such mites in pet African pygmy hedgehogs in Italy.

Objective: To evaluate the prevalence and clinical signs of C. tripilis infestation in African pygmy hedgehogs.

Animals: Clinical records of hedgehogs examined between December 2017 and December 2020 were searched retrospectively.

Methods And Materials: The prevalence of C. tripilis infestation was evaluated and exposure variables were assessed using stepwise conditional logistic regression and odds ratios (OR) were calculated.

Results: The overall prevalence of C. tripilis was 39.5% (81 of 205) in client-owned and 81.5% (66 of 81) in pet shop-housed affected hedgehogs. Fifty-two hedgehogs (64.2%) showed clinical signs of pruritus, scales, erythema, spine loss, crusting, alopecia and lichenification, while 29 infested hedgehogs (35.8%) were asymptomatic. The head was the most frequently affected area in 30 of 81 (37%) animals. In a multivariable analysis, affected hedgehogs were significantly younger [OR 0.27, 95% confidence interval (CI) 0.1-0.73; P = 0.0097] and more likely to be from a pet shop (OR 2.1, 95%CI 1-4.4; P = 0.04) than unaffected hedgehogs.

Conclusions And Clinical Importance: The results of this study indicate a prevalence rate of C. tripilis infestation that is consistent with trends observed in other studies. African pygmy hedgehogs, especially younger animals and those originating from a pet shop, should always be evaluated for C. tripilis.
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http://dx.doi.org/10.1111/vde.12991DOI Listing
June 2021

Management of factor XI deficiency in oncological liver and colorectal surgery by therapeutic plasma exchange: A case report.

Transfus Apher Sci 2021 May 31:103176. Epub 2021 May 31.

Transfusion Medicine Deparment, Hospital Italiano de Buenos Aires, Argentina.

Introduction: Factor XI (FXI) deficiency is a rare congenital hemostatic disorder associated with increased bleeding tendency in trauma, surgery or when other hemostatic defects are present. Perioperative hemostatic management of a patient with a severe FXI deficiency undergoing major oncological liver and colorectal surgery with therapeutic plasma exchange (TPE) with fresh frozen plasma (FFP) is reported.

Case Description: A 54-year-old male with severe FXI deficiency was scheduled for resection of synchronous rectal cancer and multiple liver metastases. Baseline prothrombin time (PT) was 97 %, activated partial thromboplastin time (aPTT) 89 s(s) and FXI levels <1 IU/dL. The rotational thromboelastometry (ROTEM™) presented a prolonged INTEM clotting time (CT) = 443 s (RV 100-240 s) and a clot formation time (CFT) = 110 s (RV 30-100 s). TPE with FFP was carried out achieving FXI levels up to 46 IU/dL and an aPTT of 33 s, normalizing thromboelastometry parameters to an INTEM CT = 152 s and a CFT = 86 s before the procedure. After surgery, the patient received daily FFP to maintain FXI levels above 30 IU/dL until discharge on the eighth day. A total of 30 FFP units were transfused during hospital stay. No significant bleeding events neither transfusion related complications were observed during the perioperative period.

Conclusion: Given the lack of correlation between FXI levels and bleeding risk, a multidisciplinary approach based on daily FXI levels monitoring, close clinical assessment and factor supplementation is mandatory. In conclusion, TPE with FFP is an efficacious alternative strategy to correct severe FXI deficiency in patients undergoing major surgery.
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http://dx.doi.org/10.1016/j.transci.2021.103176DOI Listing
May 2021
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