Problems of Identification according to National Catalogue of Hazardous Wastes

ldentification work of solid wastes ’ risks is a kind of improvement and amendment for environmental impact assessment document of constructed projectss. ln the research, waste identification is classified as per entrustment source and the characteristics of pol ution accidents are analyzed, with major problems of National Catalogue of Hazardous Wastes and countermeasures proposed.

An Intelligent Hazardous Waste Detection and Classification Model Using Ensemble Learning Techniques

Proper waste management models using recent technologies like computer vision,machine learning(ML),and deep learning(DL)are needed to effectively handle the massive quantity of increasing waste.Therefore,waste classification becomes a crucial topic which helps to categorize waste into hazardous or non-hazardous ones and thereby assist in the decision making of the waste management process.This study concentrates on the design of hazardous waste detection and classification using ensemble learning(HWDC-EL)technique to reduce toxicity and improve human health.The goal of the HWDC-EL technique is to detect the multiple classes of wastes,particularly hazardous and non-hazardous wastes.The HWDC-EL technique involves the ensemble of three feature extractors using Model Averaging technique namely discrete local binary patterns(DLBP),EfficientNet,and DenseNet121.In addition,the flower pollination algorithm(FPA)based hyperparameter optimizers are used to optimally adjust the parameters involved in the EfficientNet and DenseNet121 models.Moreover,a weighted voting-based ensemble classifier is derived using three machine learning algorithms namely support vector machine(SVM),extreme learning machine(ELM),and gradient boosting tree(GBT).The performance of the HWDC-EL technique is tested using a benchmark Garbage dataset and it obtains a maximum accuracy of 98.85%.

Problems of Hazardous Waste Storage Facilities in Coal-fired Power Plants and Countermeasures

The hazardous waste produced by coal-fired power plants are large in quantity and variety. It is important for ecological environment protection to properly store hazardous waste in coal-fired power plants. The environmental management of hazardous waste in coal-fired power plants started late, and there are many problems in the construction and management of their storage facilities. In this paper, taking eight typical coal-fired power plants as examples, the present problems of hazardous waste storage facilities in coal-fired power plants are analyzed, and corresponding countermeasures are put forward to solve the main common problems.

Rapid Laboratory Comparison Method for Identification of Hazardous Wastes from Illegal Oil Refining

[Objective] This paper aimed to study the rapid identification method of hazardous wastes from illegal oil refining,and provide a new theoretical basis and practical basis for shortening the appraisal cycle and reducing the cost of identification.[Method] The identified substance and the qualified oil products were diluted by carbon disulfide with a ratio of 1∶100 for the gas chromatographic analysis.According to the corresponding national standard,the oil change indexes,such as the moisture content,viscosity,acid value and mechanical impurities of the identified substance,were measured.[Result] By the comparison between the gas chromatogram spectrograms of the identified substance and the qualified oil,it is found that the main component of the identified substance was the mineral oils.And the test results of oil change index showed that the mineral oil was unqualified.[Conclusion] This method was of great significance to save the cost of appraisal and improve the efficiency of case handling.

A disposal strategy of industrial hazardous wastes in the Three Gorges Region

A large quantity of industrial hazardous wastes (IHWs) accumulates in the Three Gorges Region. This study found that approximately 15 000 t IHWs were piled in the region by October 2001. These IHWs came from various sources and were complex in composition, mostly toxic and difficult to be disposed. IHW is regarded as a potential threat to the ecological environment, water resources and survival of local residents. It is important and indispensable to dispose the waste properly. To meet the regulation requirements on the disposal of IHWs and to minimize environmental effects on the Three Gorges Region, a disposal strategy is proposed, according to which approximately 600 t of the IHWs can be disposed by chemical stabilization, incineration and other treatment measures, and the rest need be stockpiled in safe and reliable places situated above the 177 m impoundment line of the Three Gorges dam.

Simulation research of a counter‑fow 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-fow 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 fuid dynamics model of the incineration system.The infuence of the calorifc value of the hazardous waste,the operating temperature and the air supply on the operational efectiveness of the incineration system were analyzed by varying the simulation conditions.The results show that the SO_(x)and NO_(x)content of the product is lower when the operating temperature is above 800℃.The incineration system could only operate above 800℃when the calorifc 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-fow rotary kiln incineration systems.

Investigation and analysis of hazardous waste in the Three Gorges Area of Chongqing region

This article describes the investigation of hazardous waste (HW) in the Three Gorges Area of Chongqing region, which indicates that by May 2002, the dumped HW therein amounted to 14 600 t and was mainly distributed in five districts and counties with 11 000 t in Fuling, 1 650 t in Fengdu, 950 t in Wanzhou; 630 t in Wushan and 430 t in Yunyang. The total amount was composed of 9 670 t chromic residue, 2 310 t waste oil and residue, 410 t waste (false) fertilizer, 28 t waste chemical medicine, 26 t waste materials and 2 200 t other things including acid residue, waste asbestos, fluorine silicate, pigment, additive, waste acid, alkali, nitric acid, vitriol, lead mud, storage battery, calcium carbide, potassium cyanide, polluted soil, discard dynamite, waste packing barrel of cyanides, etc. In all of the HW, 578 t can be treated by chemical neutralization and stabilization technology such as redox, chemical precipitation, acid and alkali neutralization, etc., and the rest is temporarily untreatble and should be removed and piled at a temporary storage site above the 177 m water level of the dam with an aim to be transported to a future disposal site for innocuous treatment.

Current status and strategy of hazardous waste management in China

This paper deals briefly with the pollution caused by hazardous wastes in China, the hazardous waste management at present and the strategy that should be taken for hazardous waste management in the future. Hazardous waste problem has become one of the important environmental concerns in China. Hazardous waste have resulted in ecological and environmental destruction, caused damage to human health, and restricted economic development. Although a great effort has been devoted to the management of hazardous wastes, there remain many issues in legislation, experience, technology and finance to be solved. Some recommendations are made on the strategic measures for improving the hazardous waste management in China, particularly relating to legislation, technical development and international cooperation.

Current Status of Manufacturing Hazardous Waste in Shanghai

It is difficult to manage the manufacturing hazardous waste (MHW) which is generated from a huge amount of compli- cated sources and causes very serious pollution. Therefore more and more attention has been paid to MHW pollution. Shanghai, as an industrial and economic center and an international metropolis in China, has a vast industrial system spanning a multitude of sectors, which generates MHW not only in a huge magnitude but also in a large variety of types from complicated sources, resulting in severe pollution. In 2003, the production of MHW in Shanghai is about 3.96 × 105 ton, involving 33 indices. Most of MHW in Shanghai is treated and disposed of, but a significant portion is not handled properly and effectively. This paper carries out in-field investigation on the current status of MHW production and treat- ment in Shanghai, and puts forward scientific proposals that Shanghai should facilitate cleaner production and minimize haz- ardous waste; strictly enforce hazardous waste registration system, strengthen monitoring the certified enterprises; strengthen intent disposal center construction and realize hazardous waste reclama- tion; accelerate establishing the technical criteria and the man- agement policy, promote the research and development on the treatment and disposal technology, and strengthen information management, thus realizing integrated management on MHW pollution.

Ag, Hg and Cr Precipitation for Recycling Derived of Hazardous Liquid Waste

Production of different compounds can generate large amounts of hazardous wastes which are dangerous to the environment and human health. The disposal or treatment of hazardous liquid waste rich in heavy metals like silver (Ag), mercury (Hg) and chromium (Cr) is difficult due to the strong acidity and toxicity which usually present in these contaminants. For this study, several research works were reviewed in order to obtain an efficient and viable treatment in time and removal efficiency. A series of chemical precipitations were evaluated for efficiency in the reduction of heavy metals in liquid waste. The precipitation of all three metals lasted 30 minutes and after treatment the wastewater presented concentrations of 0.064 mg·L-1 Ag, 0.010 mg·L-1 Hg and 0.048 mg·L-1 Cr, with a standard pH (7.5-8.5);with removal efficiencies of 94.31% for Ag, 99.99% for Hg and 98.17% for Cr.

Key Vulnerabilities and Limitations in the Management of Hazardous Waste and Its Disposal: A Checklist Assessment Tool

From an environmental protection perspective, the crucial issues pertaining to the policing of hazardous waste relate to both the vulnerabilities and limitations of current practices, and the potential issues that demand attention in the here and now, to alleviate future calamity. This paper describes the process involved in developing a vulnerabilities and limitations checklist that provides a relatively simple yet multi-pronged approach to assessing present and future environmental harms and crimes within the hazardous waste sector. Although it was not the intention of the authors to develop a generic checklist, this tool may prove useful to other industry sectors.

Typical Refractories Design of Rotary Kiln Hazardous Waste Incineration System

This paper summarizes the current situation of China’s industrial hazardous waste treatment,the disposal technology and the characteristics of rotary kiln incineration system,analyzes the refractory lining design of rotary kiln incineration system in China,and puts forward optimization suggestions according to the process characteristics.

Corrosion-resistant Refractory Linings for Hazardous Waste Treatment inRotary Kilns

Mega trends like urbanization,industrialization and growing population drive the demand of daily necessaries and therefore result in increased refractory consumption for waste treatment carried out at elevated temperatures.It is estimated that for burning 1 t of waste about 5.5 kg of refractory materials need to be consumed.In the present study,the corrosion resistance of refractory bricks based on alumina-chromia and alumina-silica was tested by exposing them to slag from hazardous waste incineration.Samples from the cup test were investigated macroscopically and mineralogically.They showed that alumina-chromia bricks had high corrosion resistance when in contact with the tested slags,while alumina-silica bricks containing silicon carbide showed an overall good performance.

Sealed model and computation of hazardous waste landfill high voltage DC leakage detection

According to the structural characteristics of hazardous waste landfill and the leakage current model of high voltage DC Landfill leakage detection, a sealed model is established detail. The detection layer of the hazardous waste landfill is considered as a sealed assumed that the source current flows through the leak entirely. The leak is regard and analyzed in space and it is ed as a positive current resource ＋ I located at the current entrance or a negative resource - I located at the current exit, which depends on the placement of the current supply. The electrical potential of an arbitrary in detection layer satisfies Poisson equation. The boundary condition is regarded as a natural bound- ary condition for the high resistivity of high density polyethylene （HDPE） membrane. Based on which a numerical calculation method is developed. Satisfactory agreement between experimental da- ta and simulated data validates the analysis. Parametric studies show that a larger horizontal distance between the power supply electrode and leak and a smaller distance between the detector electrodes and the detected liner are helpful to leak location. More parametric curves show that parameters leaks can be detected effectively with optimum selection of field survey.

A working group set up for hazardous waste management

The national standardization working group on hazardous waste disposal and resource utilization (SAC/TC 15/WG 4) was set up on April 3,drawing over 100 research institutions,industry associations and enterprises including Solid Waste and Chemicals Management Center of the Ministry of Ecology and Environment,CNIS,Chinese Research Academy of Environmental Sciences,and Tsinghua University.

The Application and Prospect of Stabilization/Solidification Technology for Hazardous Waste in China

The number of hazardous waste in our country increased dramatically in recent years,stabilization/solidification technology begins to attract a wide spread attention by domestic scholars.Based on the domestic related literature,this paper discussed the present situation about the treatment of the solid waste using stabilization/solidification technology;meanwhile we have a variety of outlooks on the future of the stabilization/solidification technology.

The Application and Prospect of Stabilization/Solidification Technology for Hazardous Waste in China

The number of hazardous waste in our country increased dramatically in recent years,stabilization/solidification technology begins to attract a wide spread attention by domestic scholars.Based on the domestic related literature,this paper discussed the present situation about the treatment of the solid waste using stabilization/solidification technology;meanwhile we have a variety of outlooks on the future of the stabilization/solidification technology.

A Sustainable Strategy for Spent Cathode Carbon Blocks Hazardous Waste Recycling Using Binary Molten Salt Thermal Treatment

Waste-to-Energy treatment is a promising path to environment and energy management in the future.This work detailed a binary molten salt thermal treatment methodology for the detoxification of spent cathode carbon block(SCCB)waste and the recycling of carbonaceous materials.The thermal behavior of SCCB and SCCB blended with molten salts was investigated.It was found that the NaCl-Na_(2)CO_(3)binary molten salts significantly contributed to reducing pyrolysis onset temperature by 334.3 K compared to that of SCCB itself(i.e.,activation energy of pyrolysis reaction was reduced from 4.24×10^(5)to 2.30×10^(5)J/mol),thus helping to lower thermal treatment energy consumption.With the addition of binary molten salts,the residue after thermal treatment in a horizontal tube furnace experiment was separated into two layers.The bottom-layer residue was mainly composed of molten salts.The fluorine content in the form of NaF and CaF_(2)of top-layer residue was reduced significantly while the carbon content remained unchanged.Specifically,the leaching concentration of fluoride ion was decreased from 4620 mg/L to 856 mg/L.It is noted that the NaF and CaF_(2)can be removed through water-leaching and hydrothermal acid-leaching methods and thus the carbonaceous materials with a calorific value of 17.5 MJ/kg were obtained.

An ensemble machine learning model to uncover potential sites of hazardous waste illegal dumping based on limited supervision experience

With the soaring generation of hazardous waste(HW)during industrialization and urbanization,HW illegal dumping continues to be an intractable global issue.Particularly in developing regions with lax regulations,it has become a major source of soil and groundwater contamination.One dominant challenge for HW illegal dumping supervision is the invisibility of dumping sites,which makes HW illegal dumping difficult to be found,thereby causing a long-term adverse impact on the environment.How to utilize the limited historic supervision records to screen the potential dumping sites in the whole region is a key challenge to be addressed.In this study,a novel machine learning model based on the positive-unlabeled(PU)learning algorithm was proposed to resolve this problem through the ensemble method which could iteratively mine the features of limited historic cases.Validation of the random forest-based PU model showed that the predicted top 30%of high-risk areas could cover 68.1%of newly reported cases in the studied region,indicating the reliability of the model prediction.This novel framework will also be promising in other environmental management scenarios to deal with numerous unknown samples based on limited prior experience.

Geographic Information Technologies for the Study of Mass Wasting Hazards

The purpose of the research was to obtain the mass wasting hazard map for the state of Vargas, central coast of Venezuela, using GIS technology. The work was developed through the heuristic method with the generation of thematic digital maps, univariate statistical treatment, weighting of each variable and quantifying the relationship of each parameter unit regarding mass wasting processes. The algorithm designed to perform map algebra was designed using the variables: surface geology, slope, slope orientation, terrain curvature, moisture topographic index, power index surface flow rate and capacity sediment transport and the rate normalized difference vegetation. The results show a distribution of landslide hazard with the highest values in the west central part of Vargas state, where the dominant lithology is incompetent, and combined with topographic elements, determining high instability, meanwhile the lower hazard areas were found in specific areas such as the middle watershed areas east of the state. The calibration of this model shows a reliability of 80%, so it is highly advisable to use the information generated in this work by governmental and non-governmental organizations in the planning, management and use of land.