Cadmium landfill

Because of increasing environmental concerns, the disposal of all batteries is being reviewed (70—76). Traditionally silver batteries were reclaimed for the silver metal and all other alkaline batteries were disposed of in landfills or incinerators. Some aircraft and industrial nickel —cadmium batteries are rebuilt to utilize the valuable components. 

Because many batteries contain toxic constituents such as mercury and cadmium, they pose a potential threat to human health and the environment when improperly disposed. Although batteries generally make up only a tiny portion of MSW, <1%, they account for a disproportionate amount of the toxic heavy metals in MSW. For example, the U.S. EPA has reported that, as of 1995, nickel-cadmium batteries accounted for 75% of the cadmium found in MSW. When MSW is incinerated or disposed of in landfills, under certain improper management scenarios, these toxics can be released into the environment. 

Heavy metals have the potential to enter the water supply from the leachate or runoff from landfills. It is estimated that nonrecycled lead-acid batteries produce about 65% of the lead in the municipal waste stream. When burned, some heavy metals such as mercury may vaporize and escape into the air, and cadmium and lead may end up in the ash, making the ash a hazardous material for disposal. 

Levels of analyzed compounds were comparable with those reported in previous studies with the exception of cadmium, ammonia, 2(3H)benzothiazolone, and bisphenol A, which were higher than the published data regarding long-term composition of MSW landfill leachate from some European MSW landfills while... 

The evaluation of risk has underlined the possible adverse effects both on human health after the exposure to drinking water contaminated by landfill leachate and on small rodents and aquatic species at the hypothesized condition for humans, the estimated toxic effects of the raw leachate are mainly due to the levels of ammonia and cadmium and carcinogenic effects are induced by arsenic first and then by PCBs and PCDD/Fs while ecological potential risk is mainly attributable to the concentration of inorganic compounds, in particular ammonia for small rodents, cadmium, ammonia, and heavy metals for fishes. 

Tetronics A process for treating dusts from electrical arc furnaces for making steel and nonferrous metals. Volatile metals (zinc, lead, cadmium) are recovered, and residual slag is nontoxic and suitable for landfill. The dusts, mixed with coal dust and a flux, are fed to a furnace heated by a plasma gun. The metal oxides present are selectively reduced and the vapors of zinc, lead, and cadmium are condensed in a modified Imperial Smelting furnace. Developed by Tetronics Research Development Company, United Kingdom, and first commercialized for steel dusts at Florida Steel, Jackson, TN, in 1989. Seven plants were operating in several countries in 1992. 

Similar to other batteries and accumulators, the burying of cadmium batteries is a very great problem in every country, and Cd seepage from landfills and waste sites (in addition to fertilizers) is responsible for soil and water pollution and environmental risks to human and ecosystem health. The same is true for lead and mercury. 

Trace metals (arsenic, cadmium, chromium, copper, nickel, lead, mercury, zinc) Industrial and municipal wastewaters runoff from urban areas and landfill erosion of contaminated soils and sediments atmospheric deposition Toxic effects including birth defects, reproductive failure, cancer, and systemic poisoning. 

Mercury or cadmium in the contaminated material may be volatilized during treatment and therefore would have to be captured by the off-gas treatment system. If mercury or cadmium is present in the off-gas waste, it will be captured in a scrubber solution that would then require drying and stabilization prior to disposal at a landfill licensed under Resource Conservation and Recovery Act (RCRA) criteria. 

Christensen and Lun [57] developed a speciation procedure using a cation-exchange resin (Chelex 100) in a sequential batch/column/batch system for determining free divalent cadmium and cadmium complexes of various stabilities at the cadmium concentrations typically found in landfill leachates... 

Wear nitrile rubber gloves, laboratory coat, and eye protection. Avoid breathing dust. Cadmium compounds are not so toxic as to present serious disposal problems. The insoluble compounds can be mixed with wet sand, swept up, and treated as normal waste. The soluble salts can be mopped up with water, and a 10% aqueous solution of sodium metasilicate (Na2Si03-5H20) added until no further precipitation occurs. Adjust the pH to 11.0 with 2 M sulfuric acid. The solid is collected by filtration or by allowing the filtrate to evaporate in the fume hood. It is dried, packaged, and labeled for disposal in a secure landfill.14... 

Successful stabilization/solidification of cadmium in the concentration 50,000 mg l1 of Cd2+, and lead in the concentration 10,000 mg T1 of Pb2+, in the cement matrix, was obtained. Low concentrations during leaching pointed out that the heavy metal containing waste could be successfully stabilized and immobilized on this way and landfilled, or safely utilized as the building material. 

There is growing concern about the dangers of cadmium in the environment. Some rechargeable batteries are made with cadmium and nickel. Cadmium can escape from landfills (where trash is buried) and get into the ground and groundwater. From there, it can become part of the food and water that humans and other animals ingest. 

The scope of what constitutes hazards waste, an ever-present downside of the benefits we derive from the manufacture, processing, and use of chemicals and their products, continues to expand as technology moves forward. In the US two million tons of electronic products, including 50 million computers and 130 million cellphones, are disposed of every year. According to the International Association of Electronic Recylers, this number will more than triple by 2010. With such quantities in landfills and rivers, there are bound to be consequences for our air and water. Potential toxicants include lead, cadmium, and beryllium. 

Finally, water pollution arises from landfill leachates, although the causes of leachates are, rather, the remains of products on the packages. Historical packaging can also be the source of organic plasticizers for PVC, or lead and cadmium from pigments. ... 

Chromium is important in mordant dyeing. Cadmium, chromium, copper, lead, and mercury have been important in inorganic pigments. These pigments provide good heat and light stability at relatively low cost. However, their manufacture can lead to release of toxic heavy metal ions into the environment. Other releases can occur when products made from them end up for disposal in an incinerator or landfill. Many efforts are underway to replace them with less harmful materials. 

The fly ash formed in coal combustion also represents a disposal problem (see also Chap. 14). Although there are some uses such as in concrete and bricks, soil stabilization, soil conditioner, and landfill cover, more need to be found.24 Additional uses in wallboard, concrete blocks, and other construction materials should be possible. Other ashes include bottom ash and boiler slag. Experiments have been run on the recovery of iron, aluminum, and other metals from the ashes, but the processes may not be economical at this time. This could reduce the need to mine for these other materials. Coal-fired power plants produce over 100 million tons of ash annually in the United States. Coal fly ash is routinely mixed with water and put into settling basins. This process extracts some arsenic, cadmium, mercury, selenium, and strontium into water, which can then cause abnormalities in amphibians.25... 

Eggenberger and Waber 1998, Cadmium in Seepage Waters of Landfills A Statistical and Geochemical Evaluation, Report of November 20, 1997 for the OECD Advisory Group on Risk Management Meeting, February 9-10,1998, Paris, France. 

This fraction can lead to emissions of cadmium to the environment (atmospheric and water emissions). Today, in the EU members states these emissions need to be strictly controlled according to EU Directives on Waste (91/156/EEC), on Emissions from Municipal Solid Waste Incinerators (2000/76/EC), and from Landfills (99/31/EC). These emissions could be further reduced by an optimised collection efficiency of portable rechargeable batteries. 

The flue gas treatment should lead to the recovery of more than 98% of the cadmium as fly ash and wet sludge. These materials are stored in controlled landfills due to their heavy metal and other toxic material contents (Pb, Cd, Hg, As, Sb, dioxines, etc). 

The second fraction of spent Ni-Cd batteries is introduced in landfills (as illustrated in Figure 22). The EC Directive on waste imposes a strict control of leachate emissions. More than 2,000 sites have been reviewed and 95% of them show cadmium concentrations in leachates below 5 micrograms per litre (Eggenberger 2000). This represents the recommended concentration of cadmium for drinking water by the World Health Organization (WHO). This low emission level from MSW landfills has been confirmed by Swedish researchers (Flyhammer 1996). 

Several sites may have higher concentration of cadmium emissions. These are industrial waste landfills and the origin of their cadmium emissions is not proven to be from spent batteries. 

---