ABSTRACT
The present study focused on the investigation of the performance of a Moving Bed Bioreactor coupled with a Membrane Bioreactor (MBBR-MBR) on a small scale for textile wastewater treatment. The parameters examined in this study included the removal efficiency of chemical oxygen demand (COD), biochemical oxygen demand (BOD), total suspended solids (TSS), turbidity, color, and heavy metals (HM). The two reactors were operated consecutively and maintained aerobic conditions. The idea is to reduce the pollutant load significantly through the activity of microorganism attached to the biofilm covered carriers in MBBR and successive membrane filtration. The system demonstrated a favorable outcome even in a smaller hydraulic retention time (HRT) of 1 day, which presents a significant advantage in terms of cost and space saving. The removal effectiveness of COD attained a maximum of 92 %, BOD reached a maximum of 95 %, and the color removal performance obtained a removal efficiency of 87 %. Furthermore, the treatment showed remarkable efficiency in removing up to 100 % of TSS and 96 % of turbidity. Additionally, an evaluation was conducted on the elimination of heavy metals, including Zinc (Zn), Lead (Pb), Chromium (Cr), and Iron (Fe). The efficacy of removing these HMs was found to exceed 85 %. All these favorable outcomes contribute to the improvement of effluent quality, mitigation of contamination hazards, and fouling reduction.
ABSTRACT
In response to the heightened awareness of infectious diseases and the growing emphasis on personal protection in daily life, the utilization of natural bioresources for textile fabric dyeing has garnered substantial research attention. This is particularly due to their ability to confer antibacterial and UV protection properties to fabrics. In this study, the dyeing properties of Mimusops elengi Linn extract, alone and mordanted, were evaluated on blended wool/acrylic and silk fabrics, along with an assessment of their antibacterial and UV protection characteristics. The dyed fabrics exhibited good color strength and color fastness. Quantitative assessment of antibacterial activity was conducted using the reduction percentage test, while UV protection properties were determined through the measurement of Ultraviolet Protection Factor (UPF). Aqueous extract alone, when applied to blended wool/acrylic fabric, demonstrated an impressive 99.88 % reduction against Staphylococcus aureus, and 48.33 % for silk fabric, albeit less effective against Escherichia coli. Notably, when fabrics were dyed with a combination of leaves extract and various metal salt mordants, a substantial improvement in antibacterial properties was observed. Zinc and copper salts, in particular, exhibited the ability to enhance antibacterial properties to almost 100 % against Staphylococcus aureus and Escherichia coli in both blended wool/acrylic and silk fabrics. Concurrently, this combination contributed to an increase in the UV protection property of both fabrics. The findings underscore the potential of plant-based natural dye for blended wool/acrylic and silk fabrics, imparting antimicrobial and UV protection properties. This has significant implications in preventing the spread of infections and skin diseases, emphasizing the vital role of such textiles in promoting health and well-being.
ABSTRACT
Background: Identification of prior mental events of suicide attempts has immense importance in suicide prevention. However, it has not been studied in Bangladesh as there was no available psychometrically valid instrument measuring it. Objectives: We aimed to test the psychometric properties of the interpersonal needs questionnaire (INQ-15) and acquired capability for suicide scale-fearlessness about death (ACSS-FAD) in Bangla along with the determination of the level of thwarted belongingness, perceived burdensomeness, and acquired capability for suicide. Materials and methods: We collected data between 29 March and 14 April 2022 from 1,207 students of medical colleges and universities in Bangladesh by Google form. We assessed the psychometric properties of Bangla INQ and ACSS-FAD scales and examined factors associated with thwarted belongingness, perceived burdensomeness, and acquired capability for suicide. Results: The mean age of the participants was 22.82 ± 1.68 (range 18-29) years, 51% were females, 84% were graduate students, and 92% were unmarried. Both of the scales revealed acceptable levels of reliability. Confirmatory factor analysis revealed a two-factor structure of Bangla INQ after dropping three items from thwarted belongingness domain (item 9, 11, and 12) and a single factor structure for Bangla ACSS-FAD after dropping three items (item 1, 4, and 6). Perceived burdensomeness was significantly higher in females, students with a history of mental illness, family history of suicide, and the history of suicidal attempts. Fearlessness about death was significantly higher among females, non-Muslim participants, and history of suicidal attempts. Conclusion: The current study revealed psychometric properties of two suicide scales (INQ and ACSS-FAD) in Bangla that can be used in subsequent studies. Prevention strategies targeting to females, persons with psychiatric disorder, history of previous attempt(s) should be prioritized specially among the young age group.
