Anaerobic Digestion and Co-digestion of Thickened Waste Activated Sludge (TWAS) and Food Waste (FW)

This study aimed at assessing the impact of ultrasonication on the anaerobic digestibility of thickened waste activated sludge (TWAS) in anaerobic fluidized bed reactor (AnFBR), determining the unbiodegradable fraction of TWAS, and exploring co-digestion of food waste (FW) and TWAS. Two lab-scale AnFBRs treating TWAS were studied to explore the impact of ultrasonication (US) in the break down and reuse of scum for methane production. At an organic loading rate (OLR) of 4.7 kg COD/m3-d and 480 kJ of US energy, COD and VSS destruction efficiencies were 65% and 63%, respectively roughly 20% higher than the control reactor without US. To explore the specific methanogenic bacterial activity (SMA), the SMA test was conducted during OLR of 9.7 kg COD/m3-d and showed that the activity-based sludge retention time is higher for the ultrasonicated AnFBR (U-AnFBR) (7.1 days) compared to AnFBR (5.1 days). The investigation also indicated that the unbiodegradable fractions of PCOD and VSS were 0.28 based on PCOD and 0.26 based on VSS. However, to investigate the co-digestibility of FW as co-substrate, five semi-continuous flow anaerobic digesters were operated to explore the co-digestion performance treating a mixture of FW and municipal biosolids (primary sludge and TWAS) at an HRT of 20 days. Sixty days of steady-state operation at organic loading rates of 2.2 kgCOD/m3-d to 3.85 kgCOD/m3-d showed that COD removals were higher for the three co-digesters than for the two municipal biosolids digesters i.e. 61%-69% versus 47%-52%. Specific methane production per influent CODs were 1.3-1.8 folds higher in co-digestion than mono-digestion. Additional methane production through synergism accounted for the minimum 18%-20% of the overall methane production

Anammox process for nitrogen removal: development of sustainable gel beads and its application in fluidized bed reactors (FBRs)

Biological nitrogen removal (BNR) processes have been widely used for removing wastewater nitrogen because of effectiveness, economics, and environmental friendliness. Considering the energy requirements for nitrification and need for external carbon for denitrification in conventional BNR processes, anaerobic ammonia-oxidizing bacterial (anammox) processes facilitate energy-neutral or net energy positive biological treatment as well as reduce operational costs because of reduction in aeration energy, which constitutes 50%-60% of the overall energy consumption at municipal wastewater treatment plants, elimination of external organic carbon requirements, and lower sludge production. However, one of the major challenges in the practical application of the anammox process is the slow growth rate of anammox bacteria (a doubling time range of 7 – 14 days), resulting in long start-up times and biomass washout. As biomass immobilization technologies offer several advantages over convnetional suspended growth systems, including enhanced higher cell densities and biomass retention, reusability, and biomass protection from extreme environmental conditions, the main objective of this study is to develop sustainable anammox gel beads to retain the biomass in reactor efficiently. To develop sustainable anammox gel beads, four different types of anammox gel beads were prepared using sodium alginate (SA) and support materials, including distilled water (DW) as control SA bead (B1), sodium silicate as SA-SS bead (B2), polyvinyl alcohol as SA-PVA bead (B3), and colloidal silica SA-CS bead (B4). Detailed characterization and comparison of the anammox gel beads was conducted using four lab-scale semi-continuous stirred tank reactors (CSTRs) and revealed that the SA-SS beads showed superior durability with better reactor performance. SA-SS (B2) beads showed the minimum reduction in the effective diameter of 24% compared to 98%, 57%, and 96% for SA (B1), SA-PVA (B3), and SA -CS (B4), respectively indicating higher integrity of B2 beads. Moreover, the reactor containing SA-SS beads not only showed the maximum biomass retention after 30 days of operation, relative to the initial mass of 72% compared to 3%, 44%, and 5%, for SA, SA-PVA, and SA-CS, respectively but also the highest total nitrogen removal efficiencies of 80% . The diffusion coefficients (De) of ammonium in anammox gel beads was maximum for B2 beads (26.2 µm2/s) compared to B1 (18.8 µm2/s), B3 (22.4 µm2/s), and B4 (13.9 µm2/s) beads, indicating enhanced internal mass transfer. Due to the extremely slow anammox growth rate, the minimum initial concentration of anammox biomass in gel beads for rapid reactor start up was assessed at, four different initial biomass concentrations of 208 mg/L, 310 mg/L, 416 mg/L, and 540 mg/L immobilized in SA-SS beads and packed at 20% (vbead/vtotal) in four 100-ml CSTRs, and was determined to be 311 mg/L . To evaluate the effect of bead volume on nitrogen removal performance, four identical anaerobic fluidized bed reactors (AFBRs) with 0.5L working volume were inoculated with immobilized beads containing 311 mg/L of anammox biomass at packing ratios of 20%, 30%, 45%, and 60%. The optimum packing ratio (on a volumetric basis) of the AFBR was 30% (v/v) with a nitrogen removal rate (NRR) of 0.40 kg N/m3-d at volumetric nitrogen loading rate (NLR) of 0.51 kg N/m3-d, corresponding to nitrogen removal efficiencies (NRE) of 77%. A higher anammox detachment rate was observed in AFBR1 (packing ratio 20%) compared to AFBR2 (packing ratio 30%) and AFBR3 (packing ratio 45%). Finally, the impact of holed anammox gel beads on nitrogen removal performance was investigated using two lab-scale FBRs, one as control with immobilized non-holed anammox beads (CFBR) and the other with holed immobilized anammox beads (PFBR). The PFBR achieved a maximum NRR of 0.81 kg N/m3-d at NLR of 1.01 kg N/m3-d with NRE of 80% after 35 days without operational problems, whereas the CFBR with non-holed anammox gel beads failed after 30 days due to excessive biomass loss of 78% of the initial biomass from day 30 to day 36. The hindrance to diffusion of the generated nitrogen gas was the main mechanism of beads breakup and biomass washout

Occurrence, diversity and morphology of poroid wood decay by Ganoderma spp. from tropical moist deciduous forest region of Bangladesh

There are many hot spots in tropical moist deciduous forest region where wood decay fungi grow naturally. An investigation was carried  out  to  collect, identify  and  preserve wood decay Ganoderma spp. on the basis of morphological characteristics  from Pabna,  Dhaka and  Rajshahi under tropical  moist deciduous  forest  region in Bangladesh during  June  to September  2016 and July to October  2017. This study was conducted to  record the  morphological  variability,  distribution,  habitat  and diversity of  the Ganoderma  population. A  total  of  40 Ganoderma  samples  were  collected  and identified to nine species  under  Ganodermataceae family.  The samples were collected from the sites by walking through the area following standard method. The field data and laboratory analytical data was recorded during sample collection and in the laboratory, respectively.The highest density of occurrence (23%) was recorded for Ganoderma lucidum and Ganoderma oregonense followed by Ganoderma applanatum (20%), Ganoderma praelongum (19%), Ganoderma lesklokorka (18.5%), Ganoderma pfeifferi (17%), Ganoderma boninense (15%), Ganoderma lipsiense (13%) and Ganoderma tsugae (11%). The highest frequency of occurrence (10%) was recorded for Ganoderma applanatum and Ganoderma oregonense followed by Ganoderma lucidum (9%), Ganoderma pfeifferi (8%), Ganoderma boninense (8%), Ganoderma praelongum (7%), Ganoderma lesklokorka (7%),Ganoderma tsugae (6%) and  Ganoderma lipsiense (5%). During survey, Koroi (Albizia procera), Aurjun (Terminalia arjuna), Sisso plant (Dalbergia sissoo), Neem (Azadirachta indica), Golden shower (Acacia auriculiformis) and Rain tree (Albizia lebbeck) were found as hosts of Ganoderma spp. The specimens were preserved in the SAU Herbarium of Macro Fungi (SHMF) and might be useful in mushroom breeding and development program for medicine and food industry sector in future

Psychiatric disorders among the children of 5 to 18 years old of 'SIDR' affected areas

Background: Natural disasters give raise a significant amount of physical and mental impairment in human beings. Any sort of disaster acts as a causative and maintaining factor for any psychiatric morbidity. In November 15, 2007, the cyclone "SIDR" intensified to reach peak winds of 215 km/h (135 mph) according to the IMD, a peak of 250 km/h (155 mph) according to the JTWC. "SIDR" officially made landfall around 1700 UTC later that day, with sustained winds of 215 km/h (135 mph). As it intensified to a Category 4-equivalent cyclone and thus coastal districts of Bangladesh faced heavy rainfall as an early impact of the cyclone. The damage in Bangladesh was extensive, including tin shacks flattened, houses and schools blown away and enormous tree damage. The entire cities of Patuakhali, Barguna and Jhalokati District were hit hard by the storm surge of over 5 meters ( 16 ft). The head of the Red Crescent in Bangladesh expects the death toll to reach as high as 10,000. Over 3,000 other fishermen were reported missing on over 500 fishing boats. The "SIDR" left its strong impact on those who survived. Objectives: The Study was aimed to estimate the prevalence of psychiatric disorder among children and adolescents in the "SIDR" affected areas. Method: This was cross sectional, qualitative study done among the children and adolescent groups of 5 to 18 years old to see the effect of natural disaster on the people of southern part of Bangladesh. The whole of the children population who attended in the health camp were included in the study during the study period. Three teams have worked among the four "SIDR" affected districts. Each team consists of Psychiatrists, General Physicians, and Clinical Psychologist.Results: A total of 158 children in four defined areas revealed that the prevalence rate of psychiatric disorder was 48%.Conclusion: This type of study should be done in multi-centers in SIDR affected disti.icts of Bangladesh to find out the actual prevalence rate of child and adolescent psychiatric disorder

A neuroimaging study in childhood autism

Background: Childhood autism is now widely viewed as being of developmental neurological origin. Abnormality in neuroimaging is reported in autism.Objectives: To delineate the proportion of structural magnetic resonance imaging (MRI) and electro encephalography (EEG) abnormality among the children with Autism and to assess any association of MRI and EEG changes with co morbid mental illness.Methods: It was a cross sectional descriptive study done at a child and adolescent consultation centre, Dhaka. The study was Carried out from January 2009 to December 2009. Both boys and girls were included in the study. A total of 42 children with childhood autism aged between two and 12 years partici­pated in this study. Diagnosis of autism was based on ICD-10(DCR) criteria. Results: Abnormalities were found to be 35.7% in MRI and 42.9% in EEG. EEG abnormalities were found in the form of defuse slow waves activities, generalized faster activities, epileptogenic discharge and mixed discharge. The abnormalities in MRI was found in the form of diffuse cortical atrophic changes, focal cortical atrophy in frontal and temporal cortex with widening of major sulci, prominent ventricles, periventricular degeneration and abnormal basal ganglia. EEG changes were significantly associated with increased number of co-morbid illness (mental retardation, epilepsy and others). Conclusion: A number of abnom1alities that observed in the present study indicative of relations between structural and physiological dysfunctions and childhood autism. Further exploratory and in-depth researches are certainly required in this field. Intervention of autism needs to address co morbidities for better outcome

Asymmetric Ionospheric Jets in Jupiter's Aurora

Simultaneous infrared observations of (Formula presented.) and H2 emissions from Jupiter's northern aurora using the Near Infrared Spectrograph at Keck Observatory were used to measure the ionospheric and thermospheric wind velocities. (Formula presented.) ions supercorotate near the dawn auroral oval and subcorotate across the dusk sector and in the dawn polar region relative to the planetary rotation rate, broadly in agreement with past observations and models. An anticyclonic vortex is discovered in H2 flows, closely matching the mean magnetospheric subcorotation when the observed magnetospheric flows are averaged azimuthally. In comparing ion and neutral winds, we measure the line-of-sight effective ion drift in the neutral reference frame for the first time, revealing two blue-shifted sunward flows of ∼2 km/s. Observed (Formula presented.) and H2 emissions overlap with predictions of the Pedersen conductivity layer, suggesting two different regions of the ionosphere: (a) a deep layer, where neutral forces dominate the thermosphere and symmetric breakdown-in-corotation currents can close, and (b) a higher layer, where the observed effective ion drift allows dawn-to-dusk Pedersen currents within the upper atmosphere, in turn closing asymmetric currents within the magnetosphere. This ionospheric structure aligns well with recent Juno observations of Jupiter's aurora. The detected thermospheric vortex implies the driving of neutral flows by the momentum from the magnetosphere within the thermosphere and deeper in the atmosphere to potentially 20 mbar. Jovian neutral thermosphere might bridge the gap between current observations and modelings and perhaps be significant to the dynamics of aurora on Earth and other outer planets

Circulating Mucosal Associated Invariant T Cells Are Activated in Vibrio cholerae O1 Infection and Associated with Lipopolysaccharide Antibody Responses

Background: Mucosal Associated Invariant T (MAIT) cells are innate-like T cells found in abundance in the intestinal mucosa, and are thought to play a role in bridging the innate-adaptive interface. Methods: We measured MAIT cell frequencies and antibody responses in blood from patients presenting with culture-confirmed severe cholera to a hospital in Dhaka, Bangladesh at days 2, 7, 30, and 90 of illness. Results: We found that MAIT (CD3+CD4−CD161hiVα7.2+) cells were maximally activated at day 7 after onset of cholera. In adult patients, MAIT frequencies did not change over time, whereas in child patients, MAITs were significantly decreased at day 7, and this decrease persisted to day 90. Fold changes in MAIT frequency correlated with increases in LPS IgA and IgG, but not LPS IgM nor antibody responses to cholera toxin B subunit. Conclusions: In the acute phase of cholera, MAIT cells are activated, depleted from the periphery, and as part of the innate response against V. cholerae infection, are possibly involved in mechanisms underlying class switching of antibody responses to T cell-independent antigens

Enhanced Case Detection and Improved Diagnosis of PKDL in a Kala-azar-Endemic Area of Bangladesh

PKDL is a skin disorder which usually develops in 10–20% and about 60% of patients with visceral leishmaniasis (VL) after treatment respectively in the Indian subcontinent and Sudan. However, cases among people without prior VL have also been reported. Except skin lesion, PKDL patients are healthy and usually do not feel sick. However, persistence of a few PKDL cases is sufficient to initiate a new epidemic of anthroponotic VL. Thus, identifying and treating people with PKDL is a key strategy for the elimination of kala-azar. Diagnosis of PKDL relies upon clinical criteria and a serological test which is not specific for PKDL. The use of the existing laboratory diagnostic tools for confirmation of PKDL among PKDL suspects is unknown. In the Indian subcontinent, PKDL is not self-limited and needs to be treated with sodium stibogluconate injections for 4–6 months. No data are available relating to treatment compliance by patients, particularly in Bangladesh. The results of the present study showed that trained village volunteers were useful for identifying PKDL suspects, and diagnostic confirmation improved with the use of PCR. However, patients' adherence to prescribed treatment was poor

Impact of Rapid Urbanization on the Rates of Infection by Vibrio cholerae O1 and Enterotoxigenic Escherichia coli in Dhaka, Bangladesh

Bangladesh is a country where acute dehydrating diarrhea or cholera is common and is seen at least two times every year and additionally in natural disasters. In addition cholera cases have increased in the country, especially in urban settings such as in the capital city, Dhaka, where the number of hospitalized patients with more severe disease has tremendously increased. In the present observation, we have concentrated on determining the occurrence of diarrhoea caused by the two most common bacterial agents V. cholerae O1 and enterotoxigenic Escherichia coli (ETEC) in a densely populated, disease prone area Mirpur in Dhaka for two years from March 2008 to February 2010. Stool or rectal specimens from diarrheal patients coming to the ICDDR,B hospital from Mirpur were tested for the two bacterial pathogens. We found that V. cholerae O1 was the major bacterial pathogen and a cause of severe cholera disease in 23% of patients (2,647 of a total of 11,395 patients) from Mirpur. We surmise that cholera vaccines, as well as other public health tools that can target such high risk groups in the country, will be able to reduce the disease morbidity and the transmission of pathogens to improve the quality of life in urban settings