Reliability of pathogen control in direct potable reuse: Performance evaluation and QMRA of a full-scale 1 MGD advanced treatment train.

To safely progress toward direct potable reuse (DPR), it is essential to ensure that DPR systems can provide public health protection equivalent to or greater than that of conventional drinking water sources. This study collected data over a one-year period from a full-scale DPR demonstration facility, and used both performance distribution functions (PDFs) and quantitative microbial risk assessment (QMRA) to define and evaluate the reliability of the advanced water treatment facility (AWTF). The AWTF's ability to control enterovirus, Giardia, and Cryptosporidium was characterized using online monitoring of surrogates in a treatment train consisting of ozone, biological activated carbon, microfiltration, reverse osmosis, and ultraviolet light with an advanced oxidation process. This process train was selected to improve reliability by providing redundancy, defined as the provision of treatment beyond the minimum needed to meet regulatory requirements. The PDFs demonstrated treatment that consistently exceeded the 12/10/10-log thresholds for virus, Giardia, and Cryptosporidium, as currently required for potable reuse in California (via groundwater recharge and surface water augmentation). Because no critical process failures impacted pathogen removal performance during the yearlong testing, hypothetical failures were incorporated into the analysis to understand the benefit of treatment redundancy on performance. Each unit process was modeled with a single failure per year lasting four different failure durations: 15 min, 60 min, 8 h, and 24 h. QMRA was used to quantify the impact of failures on pathogen risk. The median annual risk of infection for Cryptosporidium was 4.9 × 10-11 in the absence of failures, and reached a maximum of 1.1 × 10-5 assuming one 24-h failure per process per year. With the inclusion of free chlorine disinfection as part of the treatment process, enterovirus had a median annual infection risk of 1.5 × 10-14 (no failures) and a maximum annual value of 2.1 × 10-5 (assuming one 24-h failure per year). Even with conservative failure assumptions, pathogen risk from this treatment train remains below the risk targets for both the U.S. (10-4 infections/person/year) and the WHO (approximately 10-3 infections/person/year, equivalent to 10-6 DALY/person/year), demonstrating the value of a failure prevention strategy based on treatment redundancy.

Effects of sludge properties on the thickening and dewatering of waste activated sludge.

The thickening and dewatering of waste activated sludge, from a pilot-scale submerged membrane bioreactor and two bench-scale, complete-mix activated sludge reactors (high-shear and low-shear aeration) treating the same municipal primary effluent, were investigated. Solids settling and compaction were measured using the diluted sludge volume index (DSVI) analysis and a batch centrifugation analysis, respectively. Elevated levels of filamentous microorganisms resulted in higher DSVI values and lower centrifuged pellet concentration. Elevated levels of nocardioform bacteria resulted in lower solids float concentrations, and higher colloidal material reduced solids recovery in batch flotation experiments. Sludge filterability, measured as time-to-filter, was shown to be a function of extracelluar polymeric substances and colloidal material, where higher levels of either reduced sludge filterability. Additional research is necessary to confirm these results using full- or demonstration-scale thickening and dewatering units.

A comparison of the physical, chemical, and biological properties of sludges from a complete-mix activated sludge reactor and a submerged membrane bioreactor.

The properties of sludges from a pilot-scale submerged membrane bioreactor (SMBR) and two bench-scale complete-mix, activated sludge (CMAS) reactors treating municipal primary effluent were determined. Compared with the CMAS sludges, the SMBR sludge contained a higher amount of soluble microbial products (SMP) and colloidal material attributed to the use of a membrane for solid-liquid separation; a higher amount nocardioform bacteria, resulting from efficient foam trapping; and a lower amount of extracellular polymeric substances (EPS), possibly because there was no selective pressure for the sludge to settle. High aeration rates in both the CMAS and SMBR reactors produced sludges with higher numbers of smaller particles. Normalized capillary suction time values for the SMBR sludge were lower than for the CMAS sludges, possibly because of its lower EPS content.

Influence of mixed liquor properties and aeration intensity on membrane fouling in a submerged membrane bioreactor at high mixed liquor suspended solids concentrations.

This paper presents the results of 195 days of pilot-scale submerged membrane bioreactor (SMBR) experiments on settled municipal wastewater. Short-term and long-term thickening experiments were performed at a constant membrane flux of 30L/(m(2)h) to determine the impact of the following mixed liquor properties: colloidal material, soluble COD, soluble microbial products, extracellular polymeric substances, and viscosity along with aeration intensity on membrane fouling at high mixed liquor suspended solids (MLSS) concentrations. The normalized permeability declined with increasing MLSS concentrations in all experiments and increasing the coarse bubble aeration intensity increased the permeability at a given MLSS concentration. Using a dynamic approach, this work demonstrates the importance of mixed liquor viscosity, which impacts the efficacy of the coarse bubble aeration, in sustaining membrane permeability. Over an extended thickening time period, a small increase in MLSS concentration and mixed liquor viscosity becomes more prevalent and leads to greater permeability decline at a given MLSS concentration.

The effect of organic loading on process performance and membrane fouling in a submerged membrane bioreactor treating municipal wastewater.

The results of experiments on municipal wastewater primary effluent are presented for a pilot-scale submerged membrane bioreactor (SMBR). The SMBR pilot plant employed an ultrafiltration membrane with a nominal pore size of 0.035 microm and was operated at a constant membrane flux of 30 L/m(2)h. The mixed liquor suspended solids (MLSS) concentration was maintained at 8+/-2 g/L and steady-state fouling rates were determined for 10, 5, 4, 3, and 2-d MCRTs, corresponding to food-to-microorganism (F/M) ratios of 0.34, 0.55, 0.73, 0.84, and 1.41 gCOD/gVSS d, respectively. Membrane fouling rates increased as the F/M was increased. Steady-state membrane fouling rates were correlated with total soluble microbial products (SMP) concentrations. The membrane fouling rates did not correlate well with soluble COD measured on a 0.45 microm membrane filtrate of mixed liquor or with soluble COD rejection (effluent COD/soluble COD).

Partial leptin deficiency and human adiposity.

The adipocyte-derived hormone leptin is crucial for energy homeostasis in mammals; mice and humans without it suffer from a voracious appetite and extreme obesity. The effect on energy balance of variations in plasma leptin above a minimal threshold is uncertain, however, particularly in humans. Here we examine a group of individuals who are genetically partially deficient in leptin, and show that differences in circulating leptin levels within the range found in normal human populations can directly influence the laying down of fat tissue (adiposity).

Feasibility of the membrane bioreactor process for water reclamation.

The feasibility of the membrane bioreactor (MBR) process for water reclamation was studied. Process evaluation was based on the following: literature review of MBRs, worldwide survey of MBRs, and preliminary costs estimates. The literature review and the survey have shown that the MBR process offers several benefits over the conventional activated sludge process, including: smaller space and reactor requirements, better effluent water quality, disinfection, increased volumetric loading, and less sludge production. The MBR process can exist in two different configurations, one with the low-pressure membrane modules replacing the clarifier downstream the bioreactor (in series), and the second with the membranes submerged within the bioreactor. Four major companies are currently marketing MBRs while many other companies are also in the process of developing new MBRs. The MBR process operates in a considerably different range of parameters than the conventional activated sludge process. The preliminary cost evaluation has shown that the MBR process is cost competitive with other conventional wastewater treatment processes.

Evaluation of an integrated membrane system for water repurification.

An integrated membrane system was evaluated for water repurification. Performance evaluation of the membrane system was based on three criteria: flux and fouling, disinfection capability, and rejection of pollutants. Minimal membrane fouling was observed for all of the membranes employed in the study. Significant contaminant rejection was also achieved by the membrane system purifying the reclaimed water to meet and exceed drinking water standards. Wide range of virus rejection was observed for the membranes, which was dependent on the membrane type, manufacturer, and the fouling status. Overall, the results of this study demonstrated that the integrated membrane system is a very effective and reliable process for water repurification.

Continuous infusion of glucagon induces severe hyponatremia and thrombocytopenia in a premature neonate.

We report on a 35-week gestation infant who developed severe hyponatremia and thrombocytopenia after continuous infusion of glucagon for the treatment of intractable hypoglycemia. Given these serious side effects,glucagon infusion should be avoided in the treatment of premature infants.hypoglycemia, glucose, small for gestational age. Hypoglycemia is commonly seen in premature infants, and the provision of a standard glucose intake is often not sufficient to maintain euglycemia. For these infants, an increase in glucose infusion to provide 4 to 8 mg/kg/min is initially recommended.1 Should this approach fail, pharmacologic agents such as corticosteroids or diazoxide are indicated.1 When the serum glucose in premature or small for gestational age infants cannot be adequately maintained, a glucagon infusion is now suggested as the best treatment approach.2,3 We report the use of glucagon infusion for the treatment of severe hypoglycemia in a premature infant. A severe hyponatremia associated with transient convulsions and thrombocytopenia was observed in the neonate after treatment. Discontinuation of the glucagon infusion resulted in prompt resolution of these abnormalities.

Human endogenous retrovirus with a high genomic sequence homology with IDDMK(1,2)22 is not specific for Type I (insulin-dependent) diabetic patients but ubiquitous.

AIMS/HYPOTHESIS: It has been reported recently that a novel human endogenous retroviral gene, insulin-dependent diabetes mellitus (IDDM)K(1,2)22, was expressed in the plasma of Type I diabetic patients but not in that of nondiabetic control subjects. This investigation was initiated to determine the specificity of the selective expression of IDDMK(1,2)22 in diabetic patients. METHODS: We isolated the total RNA from the plasma and lymphocytes of 13 new onset Type I diabetic patients and 10 normal control subjects and amplified it by reverse transcriptase polymerase chain reaction. We then determined the presence of IDDMK(1,2)22 with a specific primer set, U3/R-poly(A), used in a recent report and the 5 'SAg/3 'SAg primer set recognizing the putative superantigen encoding the region of the IDDMK(1,2)22 envelope (env) gene. In addition, we carried out nested PCR of the U3/R-poly(A) polymerase chain reaction product using U3N/R primers. RESULTS: We found no difference in the presence of the polymerase chain reaction products between diabetic patients and all nondiabetic subjects tested. Sequencing of the U3/R-poly(A) polymerase chain reaction products showed that the exact sequence of IDDMK(1,2)22 was not present in any of the samples tested, neither in the plasma of diabetic patients nor in that of nondiabetic control subjects. Endogenous retroviral sequences with 90-93% sequence homology to IDDMK(1,2)22 were, however, equally present in both the diabetic and nondiabetic subjects. CONCLUSION/INTERPRETATION: We conclude that a human endogenous retroviral gene with high sequence homology with IDDMK(1,2)22 is not specific for diabetic patients but, rather, is ubiquitous.

Constructing a CT table for Cryptosporidium inactivation with ozone and low turbidity waters

Se presenta un estudio iniciado en 1996 tendiente a desarrollar una base de datos sobre la inactivacion de oocistos de Cryptosporidium con ozono en aguas naturales, a distintas temperaturas. Se presentan los resultados del trabajo y, como se esperaba, se requieren mayores niveles de ozono para inactivar los oocistos de Cryptosporidium que los de Giardia

Using the coliphage naturally present in secondary effluent to monitor performance of a water repurification process in removing virus

Se exponen dos metodos para el monitoreo del agua cuyo objeto es determinar la remocion de virus en el tratamiento avanzado del agua. Ambos metodos se basan en la detecion de bacterias coliformes, el primero mediante filtracion por membrana, y el segundo, mediante agar. La metodologia ha sido presentada para evaluar el Proyecto de Repurificacion del Agua en San Diego, Estados Unidos

Using the coliphage naturally present in secondary effluent to monitor performance of a water repurification process in removing virus

Se exponen dos metodos para el monitoreo del agua cuyo objeto es determinar la remocion de virus en el tratamiento avanzado del agua. Ambos metodos se basan en la detecion de bacterias coliformes, el primero mediante filtracion por membrana, y el segundo, mediante agar. La metodologia ha sido presentada para evaluar el Proyecto de Repurificacion del Agua en San Diego, Estados Unidos

Use of immunoglobulin A-antiendomysial antibody to screen for celiac disease in North American children with type 1 diabetes.

OBJECTIVE: Our objective was to determine if a serological marker, the immunoglobulin A antiendomysial antibody (IgA-EMA), can be used to screen for celiac disease in North American children with type 1 diabetes. RESEARCH DESIGN AND METHODS: Subjects included 236 diabetes clinic patients and 56 gastrointestinal clinic patients who underwent intestinal biopsy for suspected malabsorption. Total IgA and IgA-EMA assays were performed. Diabetic patients who were positive for IgA-EMA were asked to undergo biopsy. RESULTS: Of 236 diabetic patients tested, none were IgA deficient and 19 were positive for IgA-EMA (8%). Of 17 patients biopsied, 12 had celiac disease and 3 were symptomatic. The estimated prevalence of celiac disease was 5.1%, consistent with data from European diabetic clinics. Of the 56 gastrointestinal clinic patients, the 3 who were IgA-EMA positive had biopsies diagnostic of celiac disease. Three were found to be IgA deficient, one of whom had celiac disease. Of the 50 IgA-sufficient and IgA-EMA-negative patients, 1 had celiac disease and 49 did not. The IgA-EMA test had a sensitivity of 94% and a specificity of 91% for IgA-sufficient biopsied patients. CONCLUSIONS: IgA-EMA is an appropriate tool for demonstrating an increased prevalence of celiac disease in a North American pediatric diabetic population. Positive testing should be confirmed by intestinal biopsy, and false-positive results require serial follow-up. Symptomatic children require biopsy regardless of their IgA-EMA status.

Corrosion of galvanized pipes

Esta publicación trata en detalle los problemas de la corrosión en los caños galvanizados usados en instalaciones de agua, espialmente las domiciliarias. Se habla de los procesos de fabricación y de los problemas inherentes, los métodos de caracterización, su protección, la química del zinc, las distintas formas de corrosión

Communications at the pharmacy-nursing interface.

The next evolutionary step at the pharmacy-nursing interface is the implementation of a new patient care delivery model to enhance quality and contain costs. In addition, increasingly sophisticated biotechnology drugs and drug delivery systems will require close communication and collaborative practice between pharmacy and nursing. The effective communication interface already established will form the foundation for an even closer relationship and for working together effectively and efficiently in the constantly evolving health care environment. Indeed, regardless of what the future may hold, effective communications and resultant teamwork will continue to strengthen the achievement of patient care goals and ensure a bright future for both departments.

Automated medication dispensing: the ATC 212 system.

Innovative technology is currently being designed and produced that will change the way hospital pharmacy is practiced in the future. Automated technology is becoming a powerful component of health care as human resources become scarce. The report describes a technology currently in use at a large general acute care hospital. This new automated system assists the pharmacy department by packaging and dispensing medications to be used in the centralized, computer supported cart-filling process. The ATC 212 System (Baxter Healthcare Corporation, Deerfield, IL) was reviewed and selected as a tool to enhance pharmacy operations. The system has made a positive impact on the unit dose centralized cart-fill operations. A reduction of one full-time technician, a reallocation of pharmacists' time and an increase in productivity and operational flexibility has been realized as a result of the ATC 212 system implementation.