Electrochemical Processes for the Treatment of Hazardous Wastes Exemplified by Electroplating Sludge Leaching Solutions

The solidified landfill disposal of hazardous solid waste such as electroplating sludge in arid/semi-arid areas has potential risks and hazards. In this study, the electrochemical method was used to destroy the structures of metal complexes in electroplating sludge and release metal ions so that the organics were removed by direct mineralization in the anode while the metal was recovered in the cathode. A SnO2/Ti electrode was used as the anode during the electrolysis process. The effect of different current densities (10, 20, 30, 40, 50, 60 A/m2), different pH values (2, 3, 4, 5, 6), and the presence of chloride (0.1 or 0.2 M NaCl) and sulfate (0.1 or 0.2 M Na2SO4) on treatment were investigated. Under the optimal treatment conditions (current density = 50 A/m2, pH = 3), the removal rates of CODCr, TOC, and Ni2+ reached 88.01%, 85.38%, and 97.57%, respectively, with a metal recovery of 97.01%. Further studies showed that active chlorine and active persulfate generated in the presence of chloride and sulfate had less effect on the removal of organics, while hydroxyl radicals played a major role. The dilution of the leachate would be detrimental to electrochemical treatment. The by-products of organic chlorination were produced in low amounts, mainly CHCl3. This method can be used to treat electroplating sludge in various areas to recover valuable metals while removing organic pollutants, complying with the concept of sustainable development. This method provides a new solution for the treatment of metal-containing hazardous solid waste such as electroplating sludge from the perspective of practical application.

DESIGN OF HAZARDOUS WASTE STATION IN XYZ RADIOACTIVE INDUSTRY

A hazardous waste station must be designed following Regulation of the Minister of Environment and Forestry Number P.12 of 2020 concerning the Storage of Hazardous Waste so as not to cause environmental impacts. The purpose of this design is to improve the design criteria for the hazardous waste station in accordance with applicable regulations. The type and volume of hazardous waste storage have jerry can shape in 60 and 30-liter volumes, HDPE drum, and pallet. Each container is equipped with a symbol and label. Hazardous liquid waste and hazardous solid waste are designed with the dimensions of 10.66m x 8.2m and 8.65m x 8.2m. Each is equipped with coordinate, spill kit, fire extinguisher, pallet, shower & eyewash, and container. The new design of hazardous waste selected has met the requirements in the regulation, safe from outside interference and environmental impacts.

MATHEMATICAL APPROACH ON HOUSEHOLD WASTE CAUSING ENVIRONMENTAL POLLUTANTS DUE TO LANDFILL AND TREATMENTS

Household solid waste is the solid waste mixture of garbage and rubbish which comes during the use of various products in daily life. It also called as domestic waste or residential waste. It may fall into two categories either hazardous or non-hazardous which are stored and forsaken directly to the landfills. This is how household solid waste plays vital role in spreading environmental pollutants. For reduction of the pollution, treatment plant is constructed for hazardous solid waste and compost plant is organized for non-hazardous solid waste. In this paper, we have developed a system of non-linear differential equations to analyse the household solid waste storage. In order of preventive measures, five various controls are given to the different compartments. The basic reproduction number and the stability are derived to check the endurance of the model. The numerical simulation is also done using validated data.

Use of Non-Hazardous Solid Waste as Alternative Fuels in Cement Manufacturing Process

The incineration of non-hazardous solid waste and its use as alternative fuel in cement manufacturing process was studied and simulated under the effect of air flow acceleration in a laboratory scale reactor. Firstly, analysis of the different waste materials (textile, wood and paper) was performed separately, showing that textile samples presented the highest levels of heavy metals (H.M). In the course of a test run using solid recovered fuel (SRF), the mass balance of heavy metals revealed that lead and chromium probably volatilized during firing while arsenic, cadmium and zinc were trapped in clinker. As to gaseous emissions, heavy metals concentration in the stack remained relatively low and below the standard limits. Secondly, the temperature and concentration of gases flue was monitored. It was shown that the combustion regime is characterized by low reaction temperatures and an oxygen-deficient environment. Air injection rate affected significantly the formation and degradation mechanisms of the emitted gases concentrations, particularly CO, CO2, NO, NOx, SO2. Textile waste exhibited the lowest concentration of emitted gases compared to the other types of waste.