Rh/RhOx nanosheets as pH-universal bifunctional catalysts for hydrazine oxidation and hydrogen evolution reactions

Hydrazine oxidation (HzOR) assisted hydrogen evolution is a promising effluent treatment and energy conversion method for resolving the global energy shortage and environmental crisis. However, the highly efficient and pH-universal...

Performance Evaluation of Textile Effluent Treatment Plant: Bangladesh Perspective

The present study was undertaken to evaluate the performance efficiency of an Effluent Treatment Plant (ETP) of a Textile industry located at Tongi, Bangladesh with biological treatment (BT) and Membrane Bio-Reactor (MBR) with an average inflow of 300 m3/hr. The effluent samples were collected from the inlet and outlet of the ETP on a weekly basis for a 4 weeks’ period and were analysed for key parameters such as colour, temperature, total suspended solids (TSS), Total Dissolved Solids (TDS), pH, Dissolved Oxygen (DO), Biological Oxygen Demand (BOD), and Chemical Oxygen Demand (COD). In this study, it was observed that the colour of the effluent in the inlet was dark blue and after multiple unit treatments of the colour’s final outlet the discharge, water colour was very light purple. The temperature was varied from 32.2⁰C to 34.33⁰C. The TDS was varied from 1252.5 mg/l to 1087.5 mg/l and the percentage removal efficiency of TDS was varied from 21.47% to 42.7%. The TSS was varied from 4 mg/l to 4.5 mg/l and the percentage removal efficiency of TSS was varied from 98.48% to 98.21%. The pH value was varied from 6.48 to 7.63. The DO value in the inlet was varied from 6.47 mg/l to 6.775 mg/l. The BOD was recorded from 12.75 mg/l to 17.75 mg/l and the percentage removal efficiency of BOD was varied from 89.92% to 87.24%. The COD was varied from 33.75 mg/l to 34.25 mg/l and the percentage removal efficiency of COD was varied from 91.11% to 90.5%. It is conjectured that the values of the measured parameters are seen to be within the permissible limit as per the standard of the Department of Environment (DoE) of Bangladesh.

Effective and Low-Maintenance IMTA System as Effluent Treatment Unit for Promoting Sustainability in Coastal Aquaculture

Integrated multitrophic aquaculture (IMTA) is a versatile technology emerging as an ecological and sustainable solution for traditional monoculture aquacultures in terms of effluent treatment. Nevertheless, IMTA is still poorly applied in aquaculture industry due to, among other reasons, the lack of effective, low-investment and low-maintenance solutions. In this study, one has developed a practical and low maintenance IMTA-pilot system, settled in a semi-intensive coastal aquaculture. The optimisation and performance of the system was validated using Ulva spp., a macroalgae that naturally grows in the fishponds of the local aquaculture. Several cultivation experiments were performed at lab-scale and in the IMTA-pilot system, in static mode. The specific growth rate (SGR), yield, nutrient removal, N and C enrichment, protein and pigment content were monitored. Ulva spp. successfully thrived in effluent from the fish species sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) production tanks and significantly reduced inorganic nutrient load in the effluent, particularly, NH4+, PO43− and NO3−. The enrichment of nitrogen in Ulva spp.’s tissues indicated nitrogen assimilation by the algae, though, the cultivated Ulva spp. showed lower amounts of protein and pigments in comparison to the wild type. This study indicates that the designed IMTA-pilot system is an efficient solution for fish effluent treatment and Ulva spp., a suitable effluent remediator.

SYNTHESIS OF ACTIVATED CARBON AND CMC BEADS FROM CORN HUSK FOR EFFLUENT TREATMENT

Adsorption of dyes from the effluent is a well-known and feasible method been used in the industry. In the present work we are using corn husk agricultural waste as a sustainable raw material for synthesizing activated carbon using biopolymer carboxyl methyl cellulose for formation of beads. The beads formed are been used for removal of reactive ultra-orange RGB , acid telon yellow FG 01, basic coracryl red C2B. The surface area of beads is 39.87m2 /g. The maximum adsorption of reactive orange RGB , acid telon yellow and basic coracryl red is 68.25mg/g, 72.54mg/g and 30.21mg/g for 50ml of dye solution. The stock solution 0.4g/l of dye solution was prepared for each dye respectively. The beads formed shows a variable pH from 2 to 12 which is favourable for textile effluent. This is a green approach to use the agricultural waste for waste water treatment.

Degradation of refractory organic matter in the effluent from a semi-aerobic aged refuse biofilter-treated landfill leachate by a nano-Fe3O4 enhanced ozonation process

In this study, the transformation and degradation mechanisms of refractory organic matter in biologically treated leachate from a semi-aerobic aged refuse biofilter (SAARB) in a nano-Fe3O4 enhanced ozonation process (nFe3O4-O3) were investigated in batch experiments. A continuous experiment then confirmed the effectiveness of the process for SAARB effluent treatment. In a batch experiment, the effects of influencing factors, including nFe3O4 dosage, O3 dosage and initial pH on the treatment performance of nFe3O4-O3 process, were comprehensively investigated. The results showed that when the nFe3O4 dosage = 6 g L−1, O3 dosage = 0.15 L minute−1 and initial pH = 7, the total organic carbon, absorbance at 254 nm and colour number removal efficiencies were 40.58%, 62.55% and 89.80%, respectively. In addition, most of the humic- and fulvic-like substances in the SAARB effluent were removed, and the condensation degree, aromaticity and humification degree of the organics were substantially reduced. The morphology and elemental valence state analysis showed that the nFe3O4 in the process was relatively stable and could form an nFe3O4-organic complex. Therefore, the probability of organics reacting with hydroxyl radical increased and the oxidation efficiency was enhanced. In the continuous experiment, both the O3 dosage and hydraulic retention time (HRT) were the key influencing factors. The treatment efficiency of the nFe3O4-O3 process was enhanced at a higher O3 dosage and longer HRT. The electrical energy consumption of the continuous nFe3O3-O3 process was calculated to be 17.72 kW h m−3 in SAARB effluent treatment. This study proved the feasibility of biologically treated landfill leachate treatment by the nFe3O3-O3 process.

Acid Black 194 Dye Clarifications Onto Natural And Acid/Base Activated Smectitic Clays

The present work is concerned the Acid Black 194 dye adsorption by Two smectitic clays (BJ and AJ) aged upper Eocene were sampled from Atlas Central of Tunisia in Kairouan region. Technical characterization was carried out using calcimetry and X-ray diffraction. The activation studies of clays by HCl/ Na2CO3 have been conducted to improve their physicochemical properties. The optimum result of the surface area after acid activation (aa) was 398 m2/g for BJ aa and AJ aa, after basic activation (ab) the surface area was 460 m2 /g for BJ ab and 440 m2/g for AJ ab. The characterization by XRD, chemical analysis and SEM observations, were performed before and after optimum activation.Moreover, the raw and activated samples (aa/ab) under the optimum activation conditions were used in the effluent treatment. Adsorption tests were made by batch system at 25 °C in different pH (2-12) and by varying the adsorbent amount (0.025-0.1 g). The best adsorption results were recorded with pH = 11 and amount adsorbent 0.025 g. The raw clay adsorption capacity was slightly better than activated samples. The best yield was given by BJ (94%). Therefore, clay can be used in various applications without any characteristic modification.

Perceptions of Urban Pollution of River Dependent Rural Communities and Their Impact: A Case Study in Bangladesh

This study considers the Old Brahmaputra River, Bangladesh, as a case study regarding community perceptions on urban pollution and its impact on rural communities. In doing so, in-depth individual interviews (n = 195), key informant interviews (n = 7), and focus group discussions (n = 7) were conducted by emphasizing different perspectives on urban pollution and its effects on people related to losses of fisheries resources, agricultural production, human health, and livelihood transformation. The findings illustrate that poor urban solid waste management and direct sewage discharge degrade rivers daily. The most vulnerable rural communities are directly dependent upon the river, including fishermen, farmers, and boatmen. Specific measures such as an effluent treatment plant should be established near the river, and households and commercial drains should be cut off from the direct connection with the river. Alternative income-generating activities for the stakeholders are suggested to safeguard the river from urban pollution and the wellbeing of the stakeholders.

Photocatalytic Remediation of Methylene Blue and Antibacterial Activity Study Using Schiff Base - Cu Complexes

Photocatalytic degradation of organic dyes under visible light and ultraviolet radiation is an efficient strategy for effluent treatment. This work describes the design of novel Cu(II) complexes using the ligand N'-(3-hydroxy-4-methoxybenzylidene)nicotinohydrazide and their application in the photocatalytic degradation of the organic dye, methylene blue (MB). The photocatalytic degradation of MB follows pseudo first-order kinetics with high correlation coefficient values (R2> 0.95), making them useful as simple and low-cost organic dye degradation agents. The antibacterial screening studies of the ligand and the Cu(II) complexes by disc diffusion method show the systems to exhibit activity against Escherichia coli (gram negative) and Bacillus circulans (gram positive).