Effects of Natural Zeolites on Bioavailability and Leachability of Heavy Metals in the Composting Process of Biodegradable Wastes

The bioavailability and leachability of heavy metals play an important role in the toxicity of heavy metals in the final compost followed by land application. This chapter examines the effects of natural zeolite on bioavailability of heavy metals (Zn, Cu, Mn, Fe, Ni, Pb, Cd, and Cr) in the form of water soluble and diethylenetriaminepentaacetic acid (DTPA) extractable. The toxicity characteristic leaching procedure (TCLP) test was performed to examine the leachability of heavy metals. Water solubility, DTPA extractability, leachability, and most bioavailable fractions were reduced during agitated pile composting (APC) and rotary drum composting (RDC) of water hyacinth with zeolite addition. The addition of the natural zeolite (clinoptilolite) during the composting process led to an increase in Na, Ca, and K concentrations and significantly reduced the water solubility and DTPA and TCLP extractability of heavy metals. The addition of an appropriate amount of natural zeolite during the composting process enhanced the organic matter degradation, thereby increasing the conversion into the most stabilized organic matter and reducing the bioavailability and leachability of heavy metals

Estimation of Compost Stability During Rotary Drum Composting of Municipal Solid Waste

oai:ojs2.gjestenv.com:article/2Studies are conducted to evaluate the stability of compost prepared by three combinations (C/N 16, 22 and 30) of grass cutting, mix vegetable waste, cattle dung, food waste, paper waste and saw waste in a rotary drum composter. Variations in key stability parameters were observed to assess the stability of compost. The decrease in CO2 evolution rates for the C/N 16, 22 and 30 strongly recommended the viability of rotary drum for all kind of municipal organic waste with different C/N ratios. Results indicated the compost of C/N 22 with lower final Oxygen Uptake Rate (OUR), Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) can be considered as the very mature compost with a Solvita® maturity index of 8 and were ready for usage as a soil conditioner. Therefore, it can be suggested that rotary drum composting of mixed organic waste at initial C/N ratio of 22 can produce stable compost within 20 days of composting

Speciation of trace metals (Cu, Zn, Ni, Fe and Mn) during rotary drum composting of paper mill sludge

Chemical speciation is a very proficient tool for assessing bioavailability of heavy metals. Thus, this study was carried out to detect the variation in distribution of different fractions (Exchangeable, Carbonate, Reducible, Oxidizable and Residual) of Cu, Fe, Ni, Zn and Mn and also to assess the influence of physico-chemical parameters on chemical speciation during rotary drum composting of primary paper mill sludge (PPMS). Residual fraction was established as the most dominant fraction during speciation. Concentration of Ni was found to be mostly associated with residual fraction. However, though concentration of Cu was not found very high but its bioavailability was prominent. The current study reveals that cow dung addition in optimization can influence the physico-chemical parameters, which in turn decreases the bioavailable fraction (exchangeable and carbonate) of heavy metals during composting

Heavy metal removal through bacterial biomass isolated from various contaminated sites

ABSTRACT Heavy metal contamination causes serious threat to the ecosystem. Microbe metal interaction has been most sought after topic in terms of the usage of microbes in removing heavy metals from the surrounding environment along with the bioremediation. It is the most efficient and least costly method for treating heavy metal contaminated areas. Varied number of bacteria, fungi, algae and yeasts had been reported for removing heavy metals effectively. Industrial waste, wastewater, soils, plant roots and compost have been found to be good sources of heavy metal resistant microbes. Biosorption technology applies to the inanimate biosorbents as well as to living and non-living microorganisms. Therefore, this review paper highlights the microbiological aspect of heavy metal removal in the wastewater, industrial effluents, and water from other contaminated regions. The application of microbial study in the aspects of heavy metal removal and purification of water with the adsorption technology has been focused. Thus, proving microbioremediation to be an effective field of research oriented towards heavy metal removal by microbes in the most effective, safe and economical way

Utilization of Construction and Demolition Mix Waste in the Fired Brick Production: The Impact on Mechanical Properties

The European Green Deal, which emphasizes zero-waste economies, and waste recycling in construction and building materials, has arisen due to significant worldwide needs for solid waste recovery and usage. This ambitious study focuses on recycling mixed construction and demolition (C&D) waste into burnt bricks and investigating the influence of firing temperature. While pursuing its objectives, this is dependent on raw material characterization and burnt-brick product quality assessment. The recycling of mixed C&D waste is explored by mixing the waste into two soil types (alluvial and laterite) in ratios ranging from 5% to 45% at three firing temperatures (700 °C, 850 °C and 900 °C). The utilization of mixed C&D waste in amounts of 10% at 700 °C and 25% at 850 °C and 900 °C fulfilled the Indian standard. Although a fire at 700 °C results in less optimal waste utilization, it is beneficial and recommended for reducing the carbon footprint and energy use. Additional mineralogical and microstructural analyzes are performed on the optimal fired samples. The study’s findings are promising for sustainable resource usage, reducing carbon footprint, and reducing waste disposal volume. This research is a big step toward the Sustainable Development Goals of the United Nations and a circular economy

The recycling of demolition roof tile waste as a resource in the manufacturing of fired bricks: A scale-up to the industry

This study illustrates the utilization of roof tile waste as a resource in the manufacturing of fired bricks. Although commonly referred to as demolition waste, it is technically classifed as construction and demolition waste (C&D). This demolition waste was used as a partial replacement of two soils (alluvial and laterite soil) at three firing temperatures that were considered economical (700, 850, and 900 ◦C). The waste considered was obtained from roof tiles previously fired at a low temperature below 800 ◦C, thus containing residual carbonates and clay minerals. The increased waste input resulted in higher firing shrinkage, bulk density, and water absorption while decreasing loss on ignition. An increase in firing temperature led to higher firing shrinkage, loss on ignition, and bulk density, but lower water absorption. The bricks met both Indian and ASTM standards for 2nd and 3rd class by adding 20–35 wt% of roof tile waste and firing at 850–900 ◦C in laboratory and industrial settings. The minimum acceptable quality for the produced bricks was achieved with an addition of 35 wt% waste, resulting in a water absorption of approximately 19% and a compressive strength ranging from 6 to 9 MPa. The study suggests that incorporating waste from demolished roof tiles into the production of burned bricks can be advantageous. It can partially replace the need for soils, reduce natural resource usage, lower energy consumption during production, and decrease the carbon footprint

Municipal waste management systems for domestic use

© 2017 The Authors. Every year, the average citizen of a developed country produces about half a tonne of waste, thus waste management is an essential industry. Old waste management systems based on the collection of mixed/ sorted waste and transporting it a long way to disposal sites has a significant negative impact on the environment and humans. This paper will review the available waste management systems for house- holds. Biological methods (such as composting or anaerobic digestion) and physicochemical methods (such as burning or pyrolysis) of waste utilization will be considered from the householder’s point of view. The most important features of each system will be discussed and compared. Municipal waste management systems for domestic use could eliminate or significantly reduce the stage of waste collection and transportation. Additionally, they should not require special infrastructure and at the same time should allow garbage to be changed into safe products or energy sources with no harmful emissions. The aim of the work is to identify the best available waste disposal systems for domestic use.This reported work was conducted as part of the“Design Optimisation of the HERU Waste Treatment System”project that wasfunded by Manik Ventures Limited Project ID: 10300