Peanut hull pellets as a single use sorbent for the capture of Cu(II) from wastewater

This paper investigates the ability of peanut hulls and peanut hull pellets to adsorb copper from dilute aqueous metal ion solutions in batch and fixed bed systems. The kinetics of copper uptake onto the media have been investigated in batch systems and the influence of pH and particle size on the rate and extent of copper capture determined. The Langmuir and Freundlich isotherm theories were determined; the Langmuir model was found to best represent the equilibrium isotherm data. In normalized kinetic tests at least 75% of copper removal occurred within the first 20 min; 92% removal was effected within the first 50 min. The rate of uptake was optimum within the pH range 5-7.5, and media capacities remained relatively constant at a pH above 4.0. Bench-scale column studies were performed using peanut hull pellets. The overall capacity of pelletized peanut hulls was higher than for unmodified peanut hulls. Due to their demonstrated ability for Cu(II) uptake and favorable structural characteristics, pelletized peanut hulls could gain use as a low-cost, once-through biomass filter medium for copper-bearing waste streams.     

Use of thermal analysis techniques (TG-DSC) for the characterization of diverse organic municipal waste streams to predict biological stability prior to land application

The use of organic municipal wastes as soil amendments is an increasing practice that can divert significant amounts of waste from landfill, and provides a potential source of nutrients and organic matter to ameliorate degraded soils. Due to the high heterogeneity of organic municipal waste streams, it is difficult to rapidly and cost-effectively establish their suitability as soil amendments using a single method. Thermal analysis has been proposed as an evolving technique to assess the stability and composition of the organic matter present in these wastes. In this study, three different organic municipal waste streams (i.e., a municipal waste compost (MC), a composted sewage sludge (CS) and a thermally dried sewage sludge (TS)) were characterized using conventional and thermal methods. The conventional methods used to test organic matter stability included laboratory incubation with measurement of respired C, and spectroscopic methods to characterize chemical composition. Carbon mineralization was measured during a 90-day incubation, and samples before and after incubation were analyzed by chemical (elemental analysis) and spectroscopic (infrared and nuclear magnetic resonance) methods. Results were compared with those obtained by thermogravimetry (TG) and differential scanning calorimetry (DSC) techniques. Total amounts of CO₂ respired indicated that the organic matter in the TS was the least stable, while that in the CS was the most stable. This was confirmed by changes detected with the spectroscopic methods in the composition of the organic wastes due to C mineralization. Differences were especially pronounced for TS, which showed a remarkable loss of aliphatic and proteinaceous compounds during the incubation process. TG, and especially DSC analysis, clearly reflected these differences between the three organic wastes before and after the incubation. Furthermore, the calculated energy density, which represents the energy available per unit of organic matter, showed a strong correlation with cumulative respiration. Results obtained support the hypothesis of a potential link between the thermal and biological stability of the studied organic materials, and consequently the ability of thermal analysis to characterize the maturity of municipal organic wastes and composts.     

Projection of end-of-life vehicle (ELV) population at provincial level of China and analysis on the gap between the future requirements and the current situation of ELV treatment in China

The paper describes a model for projecting the ELV population in 31 province-level regions of China in 2015, 2017, and 2020 under three scenarios, and compares the projection results with the current distribution and capacity of qualified ELV processors in China. Historical data on the population, GDP and vehicle scrap rates are combined to model ELVs. The development in vehicle ownership is modeled by a dynamic Gompertz function. We acquire a model for the changing trend of the vehicle scrap rate as motorization improves, using Japanese historical data of over 60 years. We recalculate the parameters of the model using Chinese historical data collected over a decade when applying the model to China. The paper not only presents a baseline projection of the ELV population in province-level regions of China at different levels of motorization, but also identifies the gap between the future requirements and the current situation of ELV treatment in China.     

Utilisation of IGCC slag and clay steriles in soft mud bricks (by pressing) for use in building bricks manufacturing

The subject of this study is the application to the construction of soft mud bricks (also known as pressed bricks), both green and heat-treated bodies, built from raw materials from Santa Cruz de Mudela, Ciudad Real, and IGCC slag from the power central of Puertollano (Ciudad Real, Spain). For this purpose, industrial level tests have been performed: the production of these kind of bricks from mixes of waste from ores of construction clays and to significant fraction of different ratios and clay granulometries mixed with IGCC slag. The results of this experimentation suggests that not only can IGCC slag be applied to a ceramic process, but also its use gives several advantages, as water and energy savings, as well as improvements on the final properties of products.     

Current pesticide practices and environmental issues in Vietnam: management challenges for sustainable use of pesticides for tropical crops in (South-East) Asia to avoid environmental pollution

Pesticides are widely used in modern agriculture to minimize financial losses and maintain food supplies. In southeast Asia, where agriculture is the principal economic activity, pesticides are considered essential, particularly in tropical regions seeking to enter the global economy by providing off-season fresh fruits and vegetables. The absence of a strong legal framework for pesticides facilitated a significant increase in the use of low-quality pesticides. Farmers ignore the risks, safety instructions, and protective directives when using pesticides. They are only concerned about the effectiveness of the pesticides for killing pests, without paying attention to the effects on their health and the environment. The improper usage of pesticides and the incorrect disposal of pesticide wastes contributed to the pollution of groundwater, surface water, and soil, and induced health problems in local communities. This paper describes the impact of the exposure of pesticides on human health and water resources in connection with the usage of pesticides and their management. Because of availability, the data are mainly taken for Northern Vietnam, and applied to the water quality in the delta; nevertheless, the problem relates to all countries in the delta, and similar situations may be found in other regions, particularly in Asia.     

A comparative study of two composts as filter media for the removal of gaseous reduced sulfur compounds (RSCs) by biofiltration: Application at industrial scale

This work presents the use of two composts as filter media for the treatment by biofiltration of odors emitted during the aerobic composting of a mixture containing sewage sludge and yard waste. The chemical analysis of the waste gas showed that the malodorous compounds at trace level were the reduced sulfur compounds (RSCs) which were dimethyl sulfide (Me₂S), methanethiol (MeSH) and hydrogen sulfide (H₂S). Laboratory tests for biofiltration treatment of RSCs were performed in order to compare the properties of two filter media, consisted of a mature compost with yard waste (YW) and a mixture of mature compost with sewage sludge and yard waste (SS/YW). The maximum elimination capacity (EC) values obtained with the YW mature compost as packing material were 12.5 mg m^?3 h^?1 for H₂S, 7.9 mg m^?3 h^?1 for MeSH and 34 mg m^?3 h^?1 for Me₂S, and the removal efficiency decreased in the order of: H₂S > MeSH > Me₂S. Moreover, the YW compost filter medium had a better behavior than the filter medium based on SS/YW in terms of acclimation of the microbial communities and moisture content. According to these results, a YW mature compost as packing material for an industrial biofilter were designed and this industrial biofilter was found effective under specified conditions (without inoculation and addition of water). The results showed that the maximum EC value of RSCs was 935 mg m^?3 h^?1 (100% removal efficiency, RE) for an inlet loads (IL) between 0 and 1000 mg m^?3 h^?1. Thus, YW compost medium was proven efficient for biofiltration of RSCs both at laboratory and industrial scale.