Below, is a catalogue of Bangladeshi research on biochar for industrial, non-agricultural purposes.
Hasan, M; Khalekuzzaman, M; Alamgir, M; Datta, P; Kabir, SB. 2021. A new energy-positive technological approach for wastewater treatment and bioenergy generation using a photo anoxic baffled reactor (PABR). International Journal of Environmental Science and Technology DOI10.1007/s13762-021-03168-7 Expand ABSTRACT
ABSTRACT: This study proposed a new energy-positive technological approach for wastewater treatment and bioenergy generation using an algal–bacterial symbiosis system in a photo anoxic baffled reactor (PABR). The PABR consisted of a sedimentation chamber, four regular baffled chambers, and two floated filter media chambers. The PABR was operated in the presence of natural sunlight with an average intensity of 30 µmoles/m²/s. A wide range of ORP (-215 to 255 mV) data suggested that a suitable environment condition existed in the PABR for photosynthesis, nitrification, and denitrification. Simultaneous nitrification/denitrification (SND) was observed in the first three chambers, and microbial assimilation was governed in the last four chambers. An average biochemical oxygen demand (BOD), NH3–N, total nitrogen (TN), and PO43- removal efficiencies were more than 88, 48, 36, and 42%, respectively. Moreover, hydrothermal liquefaction (HTL) was carried out for sludge and microalgae samples for bioenergy (e.g., biocrude and biochar) conversion, where the sludge sample containing microalgae and bacteria was collected from PABR and microalgae sample was collected from photobioreactor. Finally, the Fourier transform infrared spectroscopy (FTIR) analysis was done for both biocrude and biochar derived from sludge and microalgae samples, and it was suggested that the biocrude and biochar derived from sludge sample were better than that of microalgae sample.
Payel, S; Abul Hashem, M; Hasan, MA. 2021. Recycling biochar derived from tannery liming sludge for chromium adsorption in static and dynamic conditions. Environmental Technology & Innovation 24: Article Number102010 DOI10.1016/j.eti.2021.102010 Expand ABSTRACT
ABSTRACT: In tannery industry, unhairing and liming (termed as liming) are indispensable but it is a very polluting part of process when producing quality leather. Expelled wastewater from liming generates significant amounts of liming sludge. In this study, efficacies of liming sludge biochar derived for adsorption of chromium from tannery wastewater are described. The biochar was characterized by FTIR, SEM, EDX, and BET technologies, and pHzpc. Surface area and responsible functional groups of biochar were as follows: 9.2 m²/g and C-H, C-N, C-O, C=C, N-H, S=O, and O-H. EDX analysis revealed chromium adsorption and SEM images led to changes in surface morphology. pHzpc for dry liming sludge and biochar were 4.1 and 6.1, respectively. Batch adsorption was verified by assorted parameters including biochar dose, shaking speed, contact time, and dilution factor. Column study results confirm the highest chromium adsorption efficiencies of 408.12 and 533.41 mg/g for 3 cm and 5 cm bed height, respectively. Regression coefficient suggested that adsorption obeys the Freundlich isotherm and pseudo-second order kinetics in batch mode, while it follows the Yoon–Nelson model in column mode. The physicochemical parameters of tannery wastewater prior and postadsorption revealed good removal efficiencies for chloride content (Cl), chemical oxygen demand (COD), and biochemical oxygen demand (BOD) were, respectively, 50.5%, 80.1%, and 85.5%. Desorption process recovers 69.37 mg/g Cr from adsorbed biochar which could be reused in the tanning process. Consequently, an innovative state-of-the-art tannery liming sludge biochar can satisfactorily use in tannery wastewater treatment by following wealth-from-waste principle.
Saeed, T; Miah, MJ. 2021. Organic matter and nutrient removal in tidal flow-based microbial fuel cell constructed wetlands: Media and flood-dry period ratio. Chemical Engineering Journal 411: Article Number128507 DOI10.1016/j.cej.2021.128507 Expand ABSTRACT
ABSTRACT: This study assessed the integrated impact of tidal flow, microbial fuel cell (MFC), flood (F)-dry (D) period ratio, and media on organic matter, nutrient removal pathways in subsurface flow constructed wetlands that received municipal wastewater. The tidal flow-based MFC constructed wetlands were filled with organic (biochar, coal, jute fiber), waste (slag), construction materials (concrete, brick), and planted with Phragmite australis or Chrysopogon zizanioides (i.e., Vetiver). The tidal flow-based MFC wetlands were operated under sequential flood-dry periods; three F:D ratio values (i.e., 8hrs: 16hrs; 16 hrs: 8 hrs; 24 hrs: 0 hrs) were employed within three operational periods. Mean input chemical oxygen demand (COD), nitrogen (N), and phosphorus (P) load across the tidal flow-based MFC wetlands ranged between 45 and 1130, 6–71, and 0.1–25 g/m²d, respectively; removal percentages ranged between 75 and 100, 57–86, and 80–100%, respectively. Nutrient accumulation percentage in wetland plants was <7% with respect to total removal. Electrochemically active-inactive microbial degradation and media-based adsorption supported nutrient, organics removals. Flood-dry period variation influenced N removal kinetics; organics and P removals were stable throughout the experimental run. Maximum power production rates (within the experimental systems) ranged between 63 and 982 mW/m². Tidal flow-based MFC wetlands filled with organic media achieved high N removal and power production than waste, construction materials based systems.
Saeed, T; Miah, MJ; Khan, T. 2021. Intensified constructed wetlands for the treatment of municipal wastewater: experimental investigation and kinetic modelling. Environmental Science and Pollution Research 28(24):30908-30928 DOI10.1007/s11356-021-12700-8 Expand ABSTRACT
ABSTRACT: This study reports organics and nutrient removal performances of the intensified constructed wetlands, i.e., tidal flow-based microbial fuel cell (MFC) and tidal flow wetlands that received municipal wastewater. The wetland systems were filled with organic (coco peat, biochar) or waste (Jhama brick, steel slag) materials, planted with Phragmites australis or Chrysopogon zizanioides (Vetiver) species, and operated under three flood periods: 8, 16, 24 h. Input ammonia nitrogen (NH3–N), total nitrogen (TN), phosphorus (P), chemical oxygen demand (COD), and biochemical oxygen demand (BOD) load across the wetland systems ranged between 3–27, 12–78, 0.1–23, 36–1130, and 11–281 g/m2day, respectively; mean removal percentages were 60–83, 74–84, 95–100, 94–98, and 93–97%, respectively, throughout the experimental run. The wetland systems achieved similar organics and P removals; operational and media variation did not influence removal kinetics. All wetland systems achieved the highest TN removal (76–87%) when subjected to 24-h flood period. TN removal performances of waste material–based wetlands were comparable to organic media-based systems. Tidal flow-based MFC wetlands achieved better TN removal than tidal flow wetlands because of supplementary electron production through fuel cell–based organics degradation kinetics. Maximum power production rates across the tidal flow-based MFC wetlands ranged between 53 and 57 mW/m². Monod kinetics–based continuous stirred tank reactor (CSTR) models predicted NH3–N, TN, and COD removals (in wetland systems) more accurately. Kinetic models confirmed the influence of substrate (i.e., pollutant) and environmental parameters on pollutant removal routes.
Whitehead, PG; Mimouni, Z; Butterfield, D; Bussi, G; Hossain, MA; Peters, R; Shawal, S; Holdship, P; Rampley, CPN; Jin, L; Ager, D. 2021. A new multibranch model for metals in river systems: impacts and control of tannery wastes in Bangladesh. Sustainability 13(6): Article Number3556 DOI10.3390/su13063556 Expand ABSTRACT
ABSTRACT: A new multibranch Integrated Catchment (INCA) model INCA-Metals has been developed to simulate the impact of tannery discharges on river systems. The model accounts for the key chemical reaction kinetic processes operating as well as sedimentation, resuspension, dilution, mixing and redistribution of pollutants in rivers downstream of tannery discharge points and for mine discharges or acid rock drainage sites. The model is dynamic and simulates the daily behaviour of hydrology and eight metals, including cadmium, mercury, copper, zinc, lead, arsenic, manganese and chromium, as well as cyanide and ammonia. The model is semi-distributed and can simulate catchments, tributaries and instream river behaviour. The model can also account for diffuse pollution from rural runoff as well as point sources from effluent and trade discharges. The model has been applied to the new Savar tannery complex on the Dhaleshwari River system in Bangladesh to assess the impacts on pollution levels in the river system and to evaluate a set of treatment scenarios for pollution control, particularly in the dry season. It is shown that the new effluent treatment plant at Savar needs to significantly improve its operation and treatment capability in order to alleviate metal pollution in the downstream Dhaleshwari River System and also protect the Meghna River System that falls in the Bay of Bengal.
Abul Hashem, M; Hasan, M; Momen, MA; Payel, S; Nur-A-Tomal, MS. 2020. Water hyacinth biochar for trivalent chromium adsorption from tannery wastewater. Environmental and Sustainability Indicators 5: Article Number100022 DOI10.1016/j.indic.2020.100022 Expand ABSTRACT
ABSTRACT: This investigation studied the utilization of water hyacinth (Eichhornia crassipes) as biochar for adsorption of trivalent chromium ion. The prepared biochar has been characterized by Fourier transforms infrared spectroscopy (FTIR) before and after the experiment. The trivalent chromium ion adsorption efficacy on biochar was investigated considering parameters e.g., adsorbent dose, interaction time, and relative pH. In the batch-wise treatment process, 70 mL chromium loaded tannery wastewater was treated with prepared biochar as adsorbent, shaken for a fixed period, rested, and the chromium, as well as pollution load, was measured. Chromium content in the untreated wastewater and treated wastewater at optimized conditions was 3190.1 and 27.3 mg/L, respectively. The chromium ion adsorption on biochar was 99%. The chloride, biochemical oxygen demand (BOD), and chemical oxygen demand (COD) reduction were by 56%, 93.4%, and 92.6%, respectively. The use of aquatic weed Eichhornia crassipes as biochar could be a novel economical alternative to adsorb trivalent chromium ion from the tannery wastewater.
Saeed, T; Miah, MJ; Khan, T; Ove, A. 2020. Pollutant removal employing tidal flow constructed wetlands: Media and feeding strategies. Chemical Engineering Journal 382: Article Number122874 DOI10.1016/j.cej.2019.122874 Expand ABSTRACT
ABSTRACT: Six partially saturated and unsaturated tidal flow constructed wetlands (TFCWs) were studied for the removal of nitrogen, phosphorus and organics from municipal wastewater. The TFCWs were packed with organic (biochar, coal, coco-peat), waste (slag), construction (gravel, concrete block) materials and planted with Phragmites or Vetiver. Daily wastewater feeding cycle was divided into sub-cycles across all TFCWs. Experimental analyses illustrated higher nitrogen and organics removals in organic media based TFCWs (71–85% and 84–96%, respectively), when compared with those of waste, construction material based units (49–69% and 74–95%, respectively); carbon availability from organic materials increased denitrification that was also supported by energy dispersive spectroscopy (EDS) analyses. Construction and waste material based TFCWs achieved better P removals (=93%); Ca/Al/Fe ingredients of such materials allowed P removal via adsorption. Increment of wastewater contact period inside the media triggered physico-chemical and microbial removal routes. Partially saturated coal packed TFCW was the most efficient unit in terms of N removal percentage; presence of stationary water volume created anoxic environment and reduced input load, thereby improving removal performances. In terms of removal rates (g/m² d), unsaturated TFCWs showed higher removal (over partially saturated units), which could be linked with greater input load. Mass balance analyses indicated =3% N removal through plant uptake; variation of plant species did not influence N removal. Therefore, observed removal kinetics was governed by adsorption and microbial routes. The results of this study suggest that, feeding sub-cycles could improve pollutant removals in TFCWs when packed with specific media.
Saeed, T; Khan, T. 2019. Constructed wetlands for industrial wastewater treatment: Alternative media, input biodegradation ratio and unstable loading. Journal of Environmental Chemical Engineering 7(2): Article Number103042 DOI10.1016/j.jece.2019.103042 Expand ABSTRACT
ABSTRACT: This paper reports comparative pollutant removal performances across two parallel hybrid wetland trains, that were dosed with mixed industrial wastewater (with poor biodegradability); each train included two vertical flow (VF) wetlands arranged in series, followed by a surface flow (SF) wetland as the final treatment stage. VF wetlands of system 1 and 2 were packed with biological and construction materials, respectively. Input hydraulic load (HL) was fluctuated between 113.0–226.0 mm/d across first stage wetland units of both systems. Performance analyses indicated higher organics and nitrogen removal percentages in first stage VF wetland of system 1, due to carbon leaching from the employed organic bagasse and biochar media. On the other hand, lack of carbon supply from inorganic construction materials hindered such removals in first stage VF wetland of system 2, which was counter-balanced as the wastewater passed through second stage VF unit. Enhanced P removals were quantified in VF wetlands of system 2, which could be linked to P adsorption properties of the employed construction materials. VF wetlands of both systems were inefficient in terms of color compounds removal. Physico-chemical and microbial pathways enhanced removal in the last stage SF wetlands of both systems and improved overall removal. Organics and nitrogen removal rates (g/m² d) in experimental wetlands were high at upper input loadings; however, load based (g/m² d) removal percentages were high in first and third stage wetlands (of both systems) during lower loading ranges. Concentration based mean overall NH4-N, TN, P, BOD, COD and color removal percentages across both systems were: = 90.0, = 86.0, = 91.0, = 92.0, = 85.0 and = 87.0%, respectively. Such performances signify potential combination of VF (packed with biological and construction materials) and SF wetlands, for the treatment of hardly degradable industrial wastewater.
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