nan Kunal

An overview on characterization, utilization and leachate analysis of biomedical waste incinerator ash

Solid waste management is one of the major global environmental issues, as there is continuous increase in industrial globalization and generation of waste. Solid wastes encompass the heterogeneous mass of throwaways from the urban community as well as the homogeneous accumulations of agricultural, industrial and mineral wastes. Biomedical waste pose a significant impact on health and environment. A proper waste management system should be required to dispose hazardous biomedical waste and incineration should be the best available technology to reduce the volume of this hazardous waste. The incineration process destroys pathogens and reduces the waste volume and weight but leaves a solid material called biomedical waste ash as residue which increases the levels of heavy metals, inorganic salts and organic compounds in the environment. Disposal of biomedical waste ash in landfill may cause contamination of groundwater as metals are not destroyed during incineration. The limited space and the high cost for land disposal led to the development of recycling technologies and the reuse of ash in different systems. In order to minimize leaching of its hazardous components into the environment several studies confirmed the successful utilization of biomedical waste ash in agriculture and construction sector. This paper presents the overview on the beneficial use of ash in agriculture and construction materials and its leachate characteristics. This review also stressed on the need to further evaluate the leachate studies of the ashes and slag for their proper disposal and utilization.

Design and development of self-compacting concrete made with coal bottom ash

An experimental program was carried out to study the properties of self-compacting concrete (SCC) made with coal bottom ash (CBA). The mixes were prepared with CBA as partial replacement of fine aggregates. Tests were conducted for slump flow, J-ring, V-funnel, L-box and U-box, compressive strength, splitting tensile strength, deicing salt surface scaling, carbonation and rapid chloride penetration resistance. Results indicated that SCC mixes achieved 28-day compressive strength between 25.8 and 35.2 MPa and splitting tensile strength between 1.9 and 2.4 MPa. Compressive and splitting tensile strength increased with the increase in age. Carbonation depth and deicing salt surface scaling weight loss increased with the increase in CBA. Maximum carbonation depth was observed to be 1.17 mm at 90 days and 1.66 mm at 365 days for SCC with 30% CBA content. SCC mixes made with CBA exhibited very low chloride permeability resistance (between 381 and 800 Coulomb).

Influence of Bacterial-Treated Cement Kiln Dust on Strength and Permeability of Concrete

AbstractCement kiln dust (CKD), a waste by-product, is a major problem at many cement manufacturing plants because of high alkalinity, metals, and sulfates. CKD possesses the same cementitious characteristics as those of cement, but the use of high-alkaline cement kiln dust reduces the quality of the cement and the strength of the concrete. In this study, the CKD used contained high alkali (1,467u2009u2009mg/L) and hardness (467u2009u2009mg/L) content in leachate, which on treatment with bacterium Bacillus halodurans strain KG1 showed a decrease of 67.3% alkalinity, 85.6% hardness, 46% K2O, and 27% SO3 in powdered CKD after 20xa0days of treatment at 35±2°C. This study investigates the effect of bacterial-treated CKD as a partial replacement (10, 20, and 30%) for portland cement on compressive and splitting tensile strength, water absorption and porosity, ultrasonic pulse velocity, and chloride permeability of concrete at the age of 28 and 91xa0days. Utilization of 10% bacterial-treated CKD in concrete resulted in 26.6 and 25...

Bacterial treatment of alkaline cement kiln dust using Bacillus halodurans strain KG1

This study was conducted to isolate an acid-producing, alkaliphilic bacterium to reduce the alkalinity of cement industry waste (cement kiln dust). Gram-positive isolate KG1 grew well at pH values of 6–12, temperatures of 28–50 °C, and NaCl concentrations of 0–16% and thus was further screened for its potential to reduce the pH of an alkaline medium. Phenotypic characteristics of the KG1 isolate were consistent with those of the genus Bacillus, and the highest level of 16S rRNA gene sequence similarity was found with Bacillus halodurans strain DSM 497 (94.7%). On the basis of its phenotypic characteristics and genotypic distinctiveness from other phylogenetic neighbors belonging to alkaliphilic Bacillus species, the isolated strain was designated B. halodurans strain KG1, with GenBank accession number JQ307184 (= NCIM 5439). Isolate KG1 reduced the alkalinity (by 83.64%) and the chloride content (by 86.96%) of cement kiln dust and showed a potential to be used in the cement industry for a variety of applications.

Bacterial Treatment and Metal Characterization of Biomedical Waste Ash

Biomedical waste ash generated due to the incineration of biomedical waste contains large amounts of heavy metals and polycyclic aromatic hydrocarbons (PAHs), which is disposed of in regular landfills, and results in unfavorable amounts of hazardous materials seeping into the ground and may pollute surface water and groundwater. Therefore, it is essential to remove the toxicity of ash before disposal into landfills or reutilization. Environmental characteristic analysis of BMW ash showed increased hardness (1320u2009mg/L) and chloride (8500u2009mg/L) content in leachate compared to World Health Organization (WHO) and Environment Protection Agency (EPA) guidelines for drinking water (hardness, 300u2009mg/L; chloride, 250u2009mg/L). The alkalinity and pH of the ash leachate were 400u2009mg/L and 8.35, respectively. In this paper, study was carried out to investigate the metal tolerance level of bacterial isolates isolated from soil. The isolate Bacillus sp. KGMDI can tolerate up to 75u2009mg/L of metal concentration (Mn, Mo, Cr, Fe, Cu, and Zn) in enriched growth medium. This shows that the isolated culture is capable of growing in presence of high concentration of heavy metals and acts as potential biological tool to reduce the negative impact of BMW ash on the environment during landfilling.

Isolation, Characterisation of Novel Pseudomonas and Enterobacter sp. from Contaminated Soil of Chandigarh for Naphthalene Degradation

Naphthalene an organic pollutant arises from industrial operations and natural events such as forest fires. According to US EPA list of priority pollutants, naphthalene is considered as possible carcinogen due to its low solubility and bioavailability. Degradation of this recalcitrant can be carried out using physical and chemical methods but it leads to various products, most of them are toxic to the environment. Therefore, bioremediation using selected microorganisms remains the most suitable solution to treat such pollutants.