Hazardous Waste Disposal Research Articles

Effects of oxygen content on gaseous and solid products during molten salt oxidation of cation exchange resins.

Molten salt oxidation (MSO) is an advanced method for waste resins treatment; nevertheless, the research about gas product variations of resins under different stoichiometric air feed coefficient (α) is rare. The optimal working condition of hazardous waste disposal is obtained through thermodynamic equilibrium calculation, and the method to improve the treatment efficiency is found to guide the optimization of the actual experiment. In this paper, Fact Sage was used to calculate the oxidation products of cation exchange resins (CERs) at different temperatures and α, focusing on the similarities and differences through the contents of CO, CH4, CO2, and SO2 during the oxidation of CERs, the MSO of CERs, and the theoretical calculation. The results indicated that the gas products of the calculation and reality of the oxidation process of CERs are quite different, while the CO contents of CERs during MSO are close to the calculated values. The main reason for this consequence is that in the oxidation process of CERs, the S in the sulfonic acid group will form thermally stable C-S with the styrene-divinylbenzene skeleton. Moreover, the introduction of carbonate can promote the destruction of C-S and absorb SO2 as sulfate, weakening the influence of C-S on the oxidation products of CERs. The gas chromatograph results indicated that the SO2 content is reduced from 0.66% in the process of CERs oxidation to 0.28% in MSO of CERs. When 1.25 times stoichiometric air feed coefficient is fed, the sulfate content in the carbonate is the highest at 900°C, which is 23.4%.

Environmental Safeguards in the Construction of Padma Bridge

The Padma Bridge, being the largest infrastructure development project of Bangladesh, required extensive environmental safeguards to make the dream project of Bangladesh environmentally sound. Threat to biodiversity particularly breeding and migration of HIlsha (Tenualosa ilisha) fish, safe disposal of 50 million m3 of dredging spoils, disturbances and displacement of wildlife, conservation of biodiversity, plantation of trees lost to the project, control of construction related noise, air and water pollution, occupational health and safety of the workers were the main environmental impacts of the project. An Environmental Action Plan (EAP) with effective protective measures was successfully implemented. Environmental monitoring of quality of both surface and drinking water, ambient noise level, concentration of PM10, PM2.5, CO, ozone, oxides of nitrogen and sulfur in ambient air, disposal of domestic, construction and hazardous wastes, disposal of dredged spoils, use of personal protective equipment (PPE) and safety at work sites were conducted regularly by a team constituted for this purpose throughout the project period and protective measures were adopted as and when required. Increased flow, water level and temperature in Padma River due to climate change were considered in the design of the Bridge. A wildlife sanctuary has been established in the project area for flourishing of flora and fauna in the protected environment.

Study of refractory raw materials of the Republic of Kazakhstan

Important aspects of increasing the competitiveness of domestic metallurgy and mechanical engineering are increasing the durability of thermal units and involving non-traditional, cheaper energy resources in production. One of these resources is carbon waste from the aluminum industry - electrode scrap and waste from the carbon lining of electrolyzers. The problem of their use as substitutes for solid fuels (coke coal) in the metallurgical, engineering and energy industries is fluorine- and alkali-containing salts that impregnate them, destroying the traditional lining of thermal units. The development of effective refractories resistant to fluorine- and alkali-containing corrodants (melts and gases) makes it possible to increase the competitiveness and efficiency of thermal units both through the use of cheaper energy carriers and by increasing the duration of their campaign. An important aspect is the simultaneous disposal of hazardous industrial waste and the reduction of the environmental burden on the ecosphere of the Republic of Kazakhstan. The basis for the development of new refractory materials resistant to fluorine- and alkali-containing corrodants is the analysis of the existing raw material base of the Republic of Kazakhstan and the choice of materials that make it possible to obtain aluminosilicate refractories with increased chemical resistance. In the work, the phase and chemical composition of refractory clays and kaolins of the Republic of Kazakhstan were studied, their rheological and thermophysical properties were investigated. Selected raw materials for the development of technology for the production of dense aluminosilicate refractory products.

Environmental (in)justice in the Anthropocene ocean

Environmental justice refers broadly to the distribution of environmental benefits and burdens, and the fair treatment and meaningful involvement of all people in environmental decision-making and legal frameworks. The field of environmental justice initially developed out of a concern for the disproportionate distribution and impacts of environmental pollution and hazardous waste disposal on groups that have been historically and structurally marginalized, including Black populations and socio-economically disadvantaged communities. More recent environmental justice scholarship has expanded geographically and focused on a broader set of environmental hazards and harms, such as climate change impacts, biodiversity and habitat loss, and ecosystem service declines. Yet, the impacts and distribution of environmental hazards and harms in the marine environment on coastal populations has received less attention in the environmental justice literature. This narrative review paper starts to address this gap through a focus on five main areas of environmental injustice in the ocean: 1) pollution and toxic wastes, 2) plastics and marine debris, 3) climate change, 4) ecosystem, biodiversity and ecosystem service degradation, and 5) fisheries declines. For each, we characterize the issue and root drivers, then examine social and distributional impacts. In the discussion, we explore how these environmental injustices are converging and interacting, cumulative, differentiated, and geographically distributed, and briefly examine solutions and future research directions. In conclusion, we call for greater and more explicit attention to environmental justice in ocean research and policy.

Assessment of subsurface migration and simultaneous removal of Carbendazim in simulated constructed wetland through physical and numerical modeling

Indiscriminate disposal of hazardous waste into land generates harmful effects in the lithosphere. Carbendazim is widely used to prevent fungal diseases in agricultural fields and industries, such as paper, leather, and paint, in an uncontrolled manner and is reported as a possible human carcinogen when consumed. Therefore, it is urgently needed to find effective methods to remove Carbendazim from wastewater. In this investigation, Lightweight Expanded Clay Aggregate (LECA) and silty sand have been explored as alternating bed materials in a Constructed Wetland with Chrysopogon zizanioides for phytoremediation to attenuate Carbendazim from wastewater. The hydraulic conductivity of the soil and LECA were found as 1.63 × 10−7 m/s and 1.12 × 10−3 m/s, respectively. Batch adsorption test data exhibited that Langmuir and Pseudo second-order were the best fitting isotherm and kinetic models in both cases, with Regression Coefficient (R2) values of 0.99 for all also LECA had a high adsorptive capacity for the depletion of Carbendazim. Constructed Wetland study with LECA and phytoremediation using Chrysopogon zizanioides yielded maximum removal efficiency of Carbendazim in the range of 96–99.6 %, which corroborated closely with the results from the HYDRUS model. Results demonstrate the combined efficacious use of LECA and Chrysopogon zizanioides to abate Carbendazim from wastewater, which can be recommended as a cost-effective solution for its field-scale applications.

A Three-Year Comparison of Natural Gas and Diesel Transit Buses

This article details the experiences of two California public transit agencies, Sacramento Regional Transit District (RT) and SunLine Transit Agency, which replaced aging diesel buses with new compressed natural gas (CNG) buses in 1994. It compares the operating characteristics and costs of 170 CNG buses (with the same engine-chassis configuration) and 73 diesel buses in service at the same time. Equipment was tested over a three-year period for a total of 22.2 million miles.The data indicate that labor, parts, and fuel for diesel equipment cost more than for CNG buses. Both agencies also achieved significant savings in hazardous waste disposal. The study indicates payback of the incremental costs of CNG equipment is realized in six to eight years, and that both communities benefit from public transit s clean air leadership.

Research on the Informatization Management System of Hazardous Waste in Power Grid Based on the Virtual Warehouse

As the environmental protection policies become increasingly strict, hazardous waste disposal is a noteworthy issue for power grid companies to achieve clean production. Based on the radio frequency identification devices (RFID) and internet of things (IoT) technology, a virtual warehouse theory, and informatization management system was introduced in this article, which consists of waste identification and tracking, full-chain of IoT, trade matching, production forecast, and visual display. This study offers a new thought for grid companies to develop other management methods to promote environmental protection and management works.

Research on the Informatization Management System of Hazardous Waste in Power Grid Based on the Virtual Warehouse

As the environmental protection policies become increasingly strict, hazardous waste disposal is a noteworthy issue for power grid companies to achieve clean production. Based on the radio frequency identification devices (RFID) and internet of things (IoT) technology, a virtual warehouse theory, and informatization management system was introduced in this article, which consists of waste identification and tracking, full-chain of IoT, trade matching, production forecast, and visual display. This study offers a new thought for grid companies to develop other management methods to promote environmental protection and management works.

Evaluation of nonhazardous lime requirement estimation methods for Oregon soils

AbstractThe Shoemaker, McLean, and Pratt (SMP) buffer pH method has been used historically in Oregon for estimating lime requirement, however concerns regarding hazardous waste disposal have caused increased interest in nonhazardous methods. The objective was to compare nonhazardous lime requirement estimate (LRE) methods to the SMP method for predicting incubation lime requirement (LRi) for Oregon soils. Twenty‐four soils (pH ≤ 5.5) were incubated with seven rates of CaCO3 ranging from 0 to 22.4 Mg ha–1 and incubated for 90 d at 19 °C. Seven different LRE methods were evaluated and regressed against LRi for pH targets of 5.6, 6.0, and 6.4 using linear regression. The Sikora (r2 = .91–.93), modified Mehlich (r2 = .87–.90), and Sikora‐2 (r2 = .82–.93) buffer methods showed potential as alternatives to SMP (r2 = .91–.93) based on accuracy. A multilinear model combining clay content, KCl‐extractable Al, soil organic matter (SOM), extractable Mg, and pH1:2 also effectively predicted LRi (R2 = .97). The Moore–Sikora method (r2 = .89–.93) showed precision issues due to high replication variability. The single addition of Ca(OH)2 method (r2 = .67–.74) was less accurate than other evaluated methods. In conclusion, there were several viable non‐hazardous LRE method alternatives to the SMP buffer method for Oregon soils, based on accuracy and precision.

Simulation research of a counter-flow rotary kiln hazardous waste incineration system

As industrialization accelerates and the amount of hazardous waste generated gradually increases, the means of disposal of hazardous waste is of increasing concern. In this paper, a 40 t/d counter-flow rotary kiln incineration system owned by a Jiangsu environmental protection company was researched. The software Aspen Plus was used to build the mixed pyrolysis model and the software Fluent was used to build the computational fluid dynamics model of the incineration system. The influence of the calorific value of the hazardous waste, the operating temperature and the air supply on the operational effectiveness of the incineration system were analyzed by varying the simulation conditions. The results show that the SOx and NOx content of the product is lower when the operating temperature is above 800 °C. The incineration system could only operate above 800 °C when the calorific value of the hazardous waste is not less than 1500 kcal/kg. The incineration system operated best at a primary air velocity of 1.5 m/s. The simulation results in this paper serve as a guide for the operation of counter-flow rotary kiln incineration systems.

The concept of modern ecosystem for the Ural Aluminium Smelter

The main requirement for the ecosystem of a modern industrial enterprise is to ensure the reduction of human impact on the environment. Facing the strict environmental policies of today, most production companies are forced to implement additional environmental measures, which can be quite costly. The share of such costs in the cost of production is constantly rising, which is especially critical in the steel industry where the rate of return is traditionally low. An effective way of tackling this problem would be to develop and implement a strategy for a comprehensive environmental modernization of production sites. This paper examines a concept of such strategy drawn up for the Ural Aluminium Smelter. The paper describes the main aspects related to the use and disposal of hazardous production waste – i.e. red muds and flue gas emissions. The concept is aimed at minimizing the negative impact of waste on the environment by waste neutralization and utilization in the production of additional marketable products. Such potential products may include iron-bearing pellets for iron and steel industry, mortars and fertilizers. The main organic additive considered for use in the above products is peat, a natural renewable resource found locally. A special focus of the modernization concept is on the development and implementation of innovative soil material designed as a temporary cover for existing tailings aimed at preventing wind erosion. It is shown that the use of flue gases for neutralization of highly alkaline solid waste will help reduce the impact of harmful emissions.

Efficiency Assessment of Hazardous Waste Disposal in EU Countries: A Three-Stage Super-Efficiency Data Envelopment Analysis Model.

Hazardous waste pollutes the air, soil, and water and adversely affects human health if not disposed of safely. Analysis of the efficiency of hazardous waste disposal is essential to sustainable development. This paper uses the three-stage super-efficiency Data Envelopment Analysis model to measure the efficiency of 28 EU countries from 2004 to 2016. To ensure the reliability of the results, the article utilizes a one-way ANOVA statistical test to verify whether DEA results vary significantly across various EU countries. This article discusses "how inputs and outputs can be adjusted to eliminate inefficiencies" to suggest a targeted improvement. The third stage supper efficiency DEA results shows that the efficiency varies significantly across different EU countries. The main reasons for the low efficiency are high generated hazardous waste, management expenditure, greenhouse gas emissions, and inadequate waste disposal volume. Targeted proposals from three aspects are given for policymakers in EU countries: Build a resource recycling system to reduce hazardous waste. Establish a sound fee management system to reduce expenses. Optimization of disposal technology to improve incineration efficiency.

Examination of a Hazardous Waste Disposal Plant in the Context of Occupational Health and Safety

It is required to determine the factors that are dangerous in terms of occupational health and safety in hazardous waste disposal facilities, which is an area where multidisciplinary work is required. It is also needed to find solutions for preventing risks that may cause. In this study; probability, severity and frequency criteria were used as decision criteria and the importance weights of these criteria were determined with fuzzy analytical hierarchy process. Then, 46 risks identified for the five main processes such as entry of waste to the plant, waste analysis, intermediate storage of hazardous waste, disposal of hazardous waste, and auxiliary facilities; were evaluated by fuzzy TOPSIS method according to decision criteria and prioritized according to their level. It is found that the highest priority risks for all sub-process are “fire and explosion”.

An innovative optimization model for sustainable hazardous waste reverse logistics network considering co-processing in cement kilns technology

As the rapid growth in hazardous waste (HW) is threatening both the environment and public health, more efficient disposal methods are needed. This paper proposes an innovative HW reverse logistics network (RLN) considering advanced co-processing in cement kiln technology, establishing three disposal lines to reduce HW volumes, develop renewable products, reduce greenhouse gas emissions, and conserve resources. To optimise the HW disposal process, a multi-objective optimisation model comprehensively considering social, economic, and environmental dimensions is proposed. Then a numerical example is used to demonstrated the validity of the proposed model and a real-world case is conducted to demonstrate the practicality and efficiency of the proposed model in determining the most suitable hazardous waste disposal facilities, transportation routes and transportation quantities. Scenario analyses under different decision-maker attitudes towards the objectives are conducted while also considering the influence of governmental disposal subsidies. Finally, practical policy suggestions are provided to guide scientific and sustainable HW disposal. This study concludes that 1) different decision maker and disposal subsidy levels affect the optimal system decisions, 2) advanced co-processing in cement kiln technology increases the effectiveness of the HW-RLN in terms of economic and environmental perspectives, and 3) policy subsidy support could encourage the application of co-processing in cement kiln technology; a unit disposal subsidy of 160 CNY is considered suitable for “technologically pessimistic” decision-makers, while 200–220 CNY is considered suitable for “technologically optimistic” decision-makers.

Reutilization of textile sludge stabilized with low grade-MgO as a replacement of cement in mortars

Hazardous waste materials pose a serious threat to the environment. Disposal of hazardous wastes by land filling or incineration can cause secondary pollution by contamination of major land and water resources. Textile sludge is considered as a hazardous waste because of the large amount of heavy metals present in it. Stabilization and solidification (S/S) of heavy metals is generally recommended for such waste before its disposal. The alkaline nature of many construction materials makes them a potential candidate of sludge utilization. In the present study, environment friendly magnesium-based stabilizer (low grade- MgO) is used for stabilization of textile sludge. The treated sludge was then used to make mortar specimens and evaluated for their mechanical, absorption and microstructural characteristics. The leachability of heavy metals from the stabilized sludge was analyzed by Inductive Coupled Plasma Atomic Emission Spectroscopy. Low grade MgO was found to be effective in stabilizing the heavy metals, which led to their precipitation and resulted in tremendous improvement in properties of mortar mixes. Stabilization with 10% and 15% MgO produced highest compressive strength and increased pH of mortar favorably for possible use in reinforced concrete. Up to 10% replacement of cement by stabilized textile sludge was found to be optimum without negatively affecting the properties of the mortar.SEM images revealed densification of microstructure on addition of stabilized textile sludge to the mix.

Disposal of medical waste: a legal perspective in Zimbabwe

The constitution of Zimbabwe provides that everyone has the right to an environment that is not harmful to their health and well-being. However, the illegal dumping and inappropriate disposal of hazardous waste poses a danger to the health of scavengers who are directly exposed to it and to the environment when pollutants migrate into water sources, spread into air and ultimately causing widespread of infection and toxicity.2 The safe disposal of hazardous waste is governed by legislation and regulations which in turn gives effect to the constitution.

Cleaner and safer disposal of electrolytic manganese residues in cement-based materials using direct electric curing

The direct stockpiling of electrolytic manganese residues (EMR) poses a major environmental issue, and more eco-friendly disposal is urgently needed. The combination of cement solidified waste (CSW) and direct electric curing (DEC) provides a potential solution for hazard-free value-added utilization of EMR. The effects of DEC voltages and EMR dosages on mechanical properties, hydrated products, pore structure of mixture were investigated. The influencing mechanism of DEC on the properties of cement hydration was explored in-depth using TG and XRD results. The environmental and economic evolution of DEC was analyzed, and the leaching test was conducted to evaluate the immobilization of heavy metals. Results indicate that cement-EMR pastes cured in higher DEC voltage and reduced EMR dosage increase mechanical strength and improve pore structure and capillary water absorption with respect to indoor curing (IC). The increased cement dosage improves the effectiveness of CSW, while the increased DEC voltage enhances the ionic driving force. The boosted ettringite formation occurs in system after introducing DEC and amplifying the DEC voltage. The improvement of ion concentration in DEC accelerates the formation of hydration products. The CO2-e per MPa (EIF) and cost per MPa (CIF) values of paste DMP-7 cured in 12V-DEC exhibit the lowest values with respect to those cured in other voltages and IC. The decrease in the leaching amount of Mn2+ and NH4+-N as the DEC voltage increases, and the 28-d leaching concentration of Mn2+ and NH4+-N in pastes are in accordance with the national standards. The application of DEC and cement-solidified disposal for EMR could provide a potential solution for high-value and large-capacity disposal of hazardous solid waste.

Environmental Damage Due to Hazardous and Toxic Pollution: A Case Study of Citarum River, West Java, Indonesia

Until now, environmental crimes in the Citarum watershed, especially the disposal of hazardous and toxic waste (HTW) still occurs. Consequently, there are a countless number of disasters that are happening in a day. However, where is the social control of bureaucrats of the State Ministry for the Environment of the Republic of Indonesia? This research approach method was the qualitative method. The research results showed that the perpetrators of environmental damage to the Citarum watershed were not aware that the impact of environmental damage was more violent than other crimes. It was because this type of crime sometimes had unexpected impacts related to the intensity, duration, and extent of the area affected. Therefore, the efforts to prevent environmental crimes against the Citarum river water should cover various aspects. These include very strict supervision in terms of check and balance of the independent state institutions as well as the discretion given to the authorities in the disposal of hazardous and toxic waste into the Citarum River.

The world-wide waste web

Countries globally trade with tons of waste materials every year, some of which are highly hazardous. This trade admits a network representation of the world-wide waste web, with countries as vertices and flows as directed weighted edges. Here we investigate the main properties of this network by tracking 108 categories of wastes interchanged in the period 2001–2019. Although, most of the hazardous waste was traded between developed nations, a disproportionate asymmetry existed in the flow from developed to developing countries. Using a dynamical model, we simulate how waste stress propagates through the network and affects the countries. We identify 28 countries with low Environmental Performance Index that are at high risk of waste congestion. Therefore, they are at threat of improper handling and disposal of hazardous waste. We find evidence of pollution by heavy metals, by volatile organic compounds and/or by persistent organic pollutants, which are used as chemical fingerprints, due to the improper handling of waste in several of these countries.

A preliminary study of aeolian sand-cement-modified gasification slag-paste backfill: Fluidity, microstructure, and leaching risks

To realize low-cost green backfill mining, this paper proposes a novel model of aeolian sand-cement-modified gasification slag-paste backfill (ACGPB). This model realizes the safe disposal and resource utilization of hazardous solid wastes. A comprehensive experiment (including slump test, uniaxial compressive strength tests, microscopic test, and leaching toxicity tests) was conducted to explore how the mechanism of ACGPB depends on activator type and dosage. The results showed that fresh ACGPB slurry can be expressed by the Herschel-Bulkley model (R2 ≥ 0.965 in all recipes). With Na2SO4 as activator type, the yield stress, apparent viscosity, thixotropy, and slump of ACGPB slurry increased with increasing activator dosage. With CaO as activator type, the yield stress, apparent viscosity, thixotropy, and slump of ACGPB slurry fluctuated with increasing activator dosage. The mechanical properties of all recipes (not including Control group and C-C1) met the mechanical requirement (3 d ≥ 0.5 MPa and 28 d ≥ 1.0 MPa). In addition, the concentrations of all heavy metals remained within the range specified by the national standard. Specifically, the activator exerted a positive effect on the stabilization/solidification of heavy metal ions (Cu, Cd, Ba, Ni, Cr, Se, and As). Finally, FTIR, TG-DTG, SEM, and hydration heat were used to analyze the microstructure of ACGPB. The research results provide a creative way for the resource utilization of solid waste.