Burning Chemical Wastes as Fuels in Cement Kilns

Hazardous wastes in the environment represent one of our most serious problems. Ever increasing quantities of toxic wastes have contaminated our land, air, and water. Lack of adequate hazardous waste disposal facilities is a critical problem. Landfilling toxic wastes is no longer considered safe. The tragedy of the Love Canal has demonstrated the need for proper hazardous waste disposal facilities. The best organic chemical waste disposal method is process incineration. Cement kilns have been used for burning toxic chemical industrial wastes in Canada, Michigan, New York, Sweden, etc. Existing cement kilns, when properly operated, can destroy most organic chemical wastes. Even the most complex chlorinated hydrocarbons, including PCB can be completely destroyed during normal cement kiln operations, with minimal emissions to the environment. Burning toxic chemical wastes in cement kilns, and other mineral industries, is mutually beneficial to both industry, who generates such wastes, and to society and government, who want to dispose properly of such wastes in a safe, environmentally acceptable manner. The added benefit of energy conservation is important, since large quantities of valuable fuel can be saved in the manufacture of cement when such techniques are employed.     

Wastes of multilayer containers as substrate in composting processes

An evaluation of the influence and degradation of ground multilayer containers, such as Tetra Brik Aseptic (TBA), in the composting process of municipal solid wastes (MSW) is presented. Two composting piles were formed by mixing, in different proportions, an organic fraction of MSW and TBA material ground as flakes or stripes. Piles were periodically aerated by mechanical mixing. Evolution of the composting was followed by frequent measurements of suitable parameters such as temperature, moisture, ashes, total organic carbon (TOC), nitrogen, C/N ratio, pH, conductivity, nutrients, and heavy metals. As expected, aluminum and polyethylene films from TBA were not degraded during the processes, but the cardboard fraction of TBA showed a partial decomposition that was more intense in the material ground as flakes. After two months of curing, the composts were refined and analyzed to determine their nutrient and heavy-metals contents. Despite their poor aesthetic properties, mainly resulting from the presence of little pieces of plastic and aluminum films, the composts contained the required amounts of nutrients; furthermore, their heavy-metals content was below the limits proposed by some official European organizations.     

Treatment Technologies For Hazardous Wastes: Part IV A Review of Alternative Treatment Processes for Metal Bearing Hazardous Waste Streams

The U.S. Congress and the U.S. Environmental Protection Agency believe that treatment and recovery techniques should be given maximum priority when considering methods for managing the nation's generated hazardous waste. A prohibition for the disposal of certain categories of hazardous wastes either directly onto or into the land without being treated to an accepted degree prior to such disposal practice has been promulgated.¹ Wastes containing toxic metals and cyanide complexes have been selected as a group to be restricted. Due to the high generation rate associated with this category, a large capacity of waste treatment processing will be required. Existing and emerging treatment alternatives which are or have the potential to be employed for waste treatment of metal bearing wastes are presented in this paper.     

Composting of vegetable waste in subtropical climates

This experiment examined the possibility of using composting as a method of waste disposal in subtropical countries, such as the United Arab Emirates (UAE), where temperatures are high and humidity is low. In order to simulate conditions in the UAE, a representative mixture of wastes generated in the UAE was prepared and tested at ambient temperatures resembling those of subtropical countries. The mixture consisted of tomatoes, cabbage, eggplant and grass. The addition of grass (40% of the mixture by weight) adjusted the carbon/nitrogen ratio and the moisture content of the compost to the necessary level for initiating decomposition. To maintain the moisture content of the compost under severe dry hot weather, a saturated insoluble polymer (IP) was added at 20% and 60% concentration (wet weight). The mixture was then composted at three different temperatures. Results showed that the mixture requires about two weeks for stabilisation. High temperature is an advantage to the compost process; at temperatures between 40 and 60°C, the waste mixture (regardless of IP concentration) decomposed quicker than at low temperature (25°C). The addition of 20% saturated IP to the compost increases the moisture content and decomposition rate. It also increases the organic chemical content of the compost, which will be reflected by microbial activity.     

A Review of Treatment Alternatives for Wastes Containing Treatment Technologies For Hazardous Wastes: Part V

The Hazardous and Solid Waste Amendments to the Resource Conservation and Recovery Act direct the Environmental Protection Agency to determine the available treatment technologies for a number of hazardous waste streams, including halogenated organics. If it is determined that existing technology and capacity is sufficient for the safe management of the designated halogenated organic wastes, these wastes will be prohibited from land disposal, effective July 8,1987. This article summarizes the general characteristics and treatment alternatives for this waste category.     

Composting of spent pig litter in turned and forced-aerated piles

A study was carried out to compare the compositing efficiency of spent litter (a mixture of partially decomposed pig manure and sawdust) in turned and forced-aerated piles. Duplicate piles were built with manual turning (every 4 days) during composting, and duplicate piles were set up with forced aeration using an air pump. The present study demonstrated that the efficiency of composting in the turned and forced-aerated piles was similar. Spent litter in these piles reached maturity at the same time (60 days). The forced-aerated piles went through similar physical, chemical, and microbial changes with the turned piles during composting. The forced-aerated composting system was also as effective as the turned system in eliminating Salmonella sp. in the spent litter. These results suggest that a forced-aerated composting system could be used as an alternative method in composting spent litter. The similarities in temporal changes in temperature, chemical, and microbiological properties of the forced-aerated piles, compared with the turned piles, indicate that addition of a bulking agent under forced aerated composting of spent litter is not necessary. The partially decomposed sawdust in the spent litter provided enough free air space, allowing the delivery of oxygen for the microorganisms in the spent litter piles.     

实验室常见化学废弃物的危害及处理

论述了实验室几种常见废弃物的危害及处理方法，指出了废弃物必须经过有效处理，才能利于环境保护，防止意外事故发生。     

The Fate of the Recombinant DNA in Corn During Composting

Abstract

In order to make regulations that safeguard food and the environment, an understanding of the fate of transgenes from genetically modified (GM) plants is of crucial importance. A compost experiment including mature transgenic corn plants and seeds of event Bt 176 (Zea mays L.) was conducted to trace the fate of the transgene cryIA(b) during the period of composting. In bin 1, shredded corn plants including seeds were composted above a layer of cow manure and samples from the corn layer were collected at intervals during a 12-month period. The samples were tested for the transgene persistence and microbial counts and also the compost was monitored for temperature. In bin 2, piles of corn seeds, surrounded by sheep manure and straw, were composted for 12 months. A method combining nested polymerase chain reaction (PCR) and southern hybridization was developed for detection of the transgene in compost. The detection sensitivity was 200 copies of the transgene per gram of dry composted corn material. Composting commenced on day 0, and the transgene was detected in specimens from bin 1 on days 0 and 7 but not on day 14 or thereafter. The transgene in corn seeds was not detectable after 12 months of composting in bin 2. Temperatures in both bins rose to about 50°C within 2 weeks and remained above that temperature for about 3 months, even when the ambient temperature dropped below ?20°C. Extracts from compost were inoculated onto culture plates and then were incubated at 23 to 55°C. Within the first 2 weeks of composting in bin 1, the counts of bacteria incubated at 55°C increased from 3.5 to 7.5 log ₁₀, whereas those incubated at 23°C remained at about 7.5 log ₁₀. The counts of fungi incubated at 45°C increased slightly from 2.5 to 3.1 log₁₀, but those incubated at 23°C decreased from 6.3 to 3.0 log ₁₀. The rapid degradation of the transgene during composting of Bt corn plants suggested that the composting process could be used for safe disposal of transgenic plant wastes.     

牛粪堆肥腐殖质的动态变化研究

牛粪堆肥实质是有机物质分解的同时形成腐殖质的过程。本研究通过向牛粪中接种发酵微生物进行堆肥,研究分析了总有机碳含量、总腐殖酸、游离腐殖酸和水溶性腐殖酸等的腐殖质物质含量的动态变化。研究结果表明：在牛粪发酵过程中,总有机碳含量呈明显降低趋势,发酵微生物处理下的下降幅度明显大于不接种发酵微生物的处理;总腐殖酸、游离腐殖酸和水溶性腐殖酸含量在发酵前期呈明显的降低趋势,但至发酵腐熟期又逐渐升高。发酵前期,外源微生物的处理,使其下降幅度明显大于不接种外源微生物的处理,但在发酵腐熟期变化不大。     

Composting of wastewater treatment sludge with different bulking agents

The main objectives of this study were to investigate the compostability of wastewater treatment sludge (WTS) containing different bulking agents (BAs) and to determine the most efficient BA. Four different compost trials consisting of mixtures of wheat straw (WS), plane leaf (PL), corncob (CC) and sunflower stalk (SS) with WTS were performed in laboratory reactors. In all experiments, a mixture of 60% WTS and 40% BA (wet basis) was used. The temperature, dry matter (DM), organic matter (OM), pH, electrical conductivity (EC) and C/N ratio were monitored during the composting process. Evaluation of the operational parameters showed that the highest organic matter degradation (i.e. 37.6%), loss of dry matter (i.e. 29.6%) and temperature (i.e. 64 °C) were achieved for the WTS-CC mixtures. Results also showed that the WTS-SS mixture was also successful in terms of these operational parameters. Use of bulking agents for the treatment of wastewater treatment sludge in composting process is an important issue with regards to process efficiency, economy and disposal of agricultural waste. Corncob and sunflower stalk that were previously not used for the composting of WTS from food industry were shown to be highly successful BA materials in this study.

Implications: The compostability of wastewater treatment sludge from the food industry with different bulking agents was studied. Wheat straw, plane leaf, corncob, and sunflower stalk were used as bulking agents. The required microbial stabilization and degree of mineralization were achieved with corncobs and sunflower stalks.     

Vermicomposting of Winery Wastes: A Laboratory Study

In Mediterranean countries, millions of tons of wastes from viticulture and winery industries are produced every year. This study describes the ability of the earthworm Eisenia andrei to compost different winery wastes (spent grape marc, vinasse biosolids, lees cakes, and vine shoots) into valuable agricultural products. The evolution of earthworm biomass and enzyme activities was tracked for 16 weeks of vermicomposting, on a laboratory scale. Increases in earthworm biomass for all winery wastes proved lower than in manure. Changes in hydrolytic enzymes and overall microbial activities during the vermicomposting process indicated the biodegradation of the winery wastes. Vermicomposting improved the agronomic value of the winery wastes by reducing the C:N ratio, conductivity and phytotoxicity, while increasing the humic materials, nutrient contents, and pH in all cases. Thus, winery wastes show potential as raw substrates in vermicomposting, although further research is needed to evaluate the feasibility of such wastes in large-scale vermicomposting systems.     

化工固体废物的综合利用

对我国化工固废的产生、治理、利用和重点化工行业氯碱工业等化工固体废弃物的处理和综合利用技术进行了分析、综述，并指出了该领域的发展趋势。     

Composting of spent pig litter at different seasonal temperatures in subtropical climate

To investigate the effects of seasonal temperatures on the composting of spent pig-manure sawdust litter (spent litter), two sets of experiments were carried out: one during winter, the other during summer. Physicochemical and microbial parameters including temperature, pH, inorganic N, humification indicators (HA and FA), heavy metals (Cu and Zn), total aerobic heterotrophs, ATP content and dehydrogenase activity were measured to understand changes in the spent litter during composting. Results demonstrated that the composting was faster during summer than winter. The spent litter during the summer trial reached maturity at day 56 whereas that of the winter trial was still immature at the end of composting (days 91). Microbial activities during the thermophilic stage of composting were much lower in the winter trial. Values began to increase during the latter part of composting, indicating that the spent litter in this winter trial was biologically unstable and must be further composted to reach full maturity. The changes in the microbial activities of the spent litter during summer or winter reflected the changes in their temperatures and chemical properties. The maturation of the spent litter during summer was accompanied by stabilization of the microbial and chemical properties and a drop in temperature to ambient level. Results of correlation analysis showed that temperature correlated not only with the microbial parameters but also with most of the chemical parameters. These parameters also correlated with each other. Among all the parameters measured, the trend of temperature changes is the simplest and most rapid parameter that can be used to evaluate the maturity of spent litter.     

扬州市危险废弃物现状及处置措施

通过对扬州市危险废弃物环境管理现状的分析,提出了加强危险废物环境管理的几点措施.     

Processes controlling metal transport and retention as metal-contaminated groundwaters efflux through estuarine sediments

Factors affecting the transport and retention of Cd, Cr, Cu, Ni, Pb and Zn in acidic groundwaters as they pass through estuarine sediments were investigated using column experiments. Acidic groundwaters caused the rapid dissolution of iron sulfide (AVS) and other iron and manganese phases from sediments that are important for metal binding and buffering. Metal breakthrough to overlying water occurred in the order of Ni>Zn>Cd>Cu>Cr/Pb. Metal transport increased as the sediment permeability increased, reflecting the low resistance to flow caused by larger sand-sized particles and the decreased abundance of metal adsorption sites on these materials. Metal mobility increased as the groundwater pH decreased, as flow rate or metal concentrations increased, and as the exposure duration increased. Groundwater Cr and Pb were promptly attenuated by the sediments, the mobility of Cu was low and decreased rapidly as sediment pH increased above 4.5, while Cd, Ni and Zn were the most easily transported to the surface sediments and released to the overlying waters. For groundwaters of pH 3, metal migration velocities through sandy sediments were generally 0.5-2% (Cr, Pb), 1-6% (Cu) and 4-13% (Cd, Ni, Zn) of the total groundwater velocity (9-700 m/yr). The oxidative precipitation of Fe(II) and Mn(II) in the groundwaters did not affect metal mobility through the sediments. The results indicated that the efflux of acidic and metal-contaminated groundwater through estuarine sediments would affect organisms resident in sandy sediments more greatly than organisms resident in fine-grained, silty, sediments.     

基于新型分层结构的污泥好氧堆肥处理

为了提高堆肥效率以及改进传统的堆肥方式,采用分层的堆置方式,以竹炭作为分隔材料,进行好氧堆肥实验,系统地分析了堆肥过程中常规理化特性的变化以及氮素损失情况。结果表明:木屑处理组(A)和竹炭处理组(B)中温度均经历了升温期、高温期以及降温期3个阶段,满足堆肥3阶段理论;以竹炭作为分层材料使高温期pH值降低至8.23,低于A组(8.98),而pH值的降低有利于控制氨气挥发;堆肥结束时,B组中DOC降解率为75.3%,明显高于A组(60.2%)。B组处理中氨气累积释放量为2 127.8 mg,小于A组的2 522.8 mg,可见竹炭作为堆体分隔材料对堆肥过程有机质的降解利用以及氨气挥发的控制均有一定的促进作用。     

Thermal Exploitation of Wastes with Lignite for Energy Production

Abstract

The thermal exploitation of wastewood with Greek lignite was investigated by performing tests in a laboratory-scale fluidized bed reactor, a 1-MW_th semi-industrial circulating fluidized bed combustor, and an industrial boiler.

Blends of natural wood, demolition wood, railroad sleepers, medium-density fiberboard residues, and power poles with lignite were used, and the co-combustion efficiency and the effect of wastewood addition on the emitted pollutants were investigated. Carbon monoxide, sulfur dioxide, and oxides of nitrogen emissions were continuously monitored, and, during the industrial-scale tests, the toxic emissions (polychlorinated dibenzodioxins and dibenzofurans and heavy metals) were determined. Ash samples were analyzed for heavy metals in an inductively coupled plasma-atomic emission spectroscopy spectrophotometer.

Problems were observed during the preparation of wastewood, because species embedded with different compounds, such as railway sleepers and demolition wood, were not easily treated. All wastewood blends were proven good fuels; co-combustion proceeded smoothly and homogeneous temperature and pressure profiles were obtained. Although some fluctuations were observed, low emissions of gaseous pollutants were obtained for all fuel blends. The metal element emissions (in the flue gases and the solid residues) were lower than the legislative limits. Therefore, wastewood co-combustion with lignite can be realized, provided that the fuel handling and preparation can be practically performed in large-scale installations.     

铜酞菁生产中的三废综合治理及其资源化探讨

通过某铜酞菁化工生产企业三废治理及其资源化工艺改进的实践，总结出了一套行之有效的利用酸化工艺废酸的资源化新方法，不但从中回收了高价值的铜泥；同时利用废酸吸收生产工艺中的高含氨尾气，生产硫酸铵，达到了以废治废的目的，整个治理工艺符合循环经济的理念。通过该回收工艺的改进，使上述三废不再进入污水处理系统，从而解决了传统铜酞菁生产废水的高酸度、高盐分、高含氨、高难处理的矛盾，使铜酞菁三废处理易于实行。     

Case Studies of Minimizing Plating Bath Wastes in the Electronics Products Industry

In this paper the authors report on the results of case studies carried out under the sponsorship of the U.S. EPA to determine the effectiveness of four processes designed to reduce the amount of hazardous waste from plating operations. Data reported are based on the results of actual on-site sampling of the processes and encompass effectiveness, environmental, and economic considerations. Two of the case studies evaluating the use of sodium borohydride reduction as a substitute for lime/ferrous sulfate precipitation, found that the technology was a viable substitute in one case and was marginally acceptable in another. Another case study, involving carbon adsorption removal of organic contaminants from plating bath wastes, found that this technology significantly reduced both disposal costs and waste volume. A final case study of electrolytic recovery indicated that while acid copper electroplating rinses are amenable to electrolytic recovery, other metal-bearing rinses, such as those from solder (tin/lead) plating or etching are less appropriate.