高酚焦化废水萃取脱酚预处理

为了降低高酚焦化废水中挥发酚的浓度，实验研究了磷酸三丁酯煤油溶液在不同条件下对高酚焦化废水进行萃取脱酚预处理的效果。结果表明，萃取时间为8min，磷酸三丁酯煤油浓度为30％，温度低于40％，pH低于8．0，萃取比（油／水）R=1：2时，经过萃取后分水挥发酚浓度由4165mg降低到127．62mg／L，去除率高达96．94％，为后续生化处理奠定了基础。而萃取剂经过氢氧化钠溶液反萃取再生后，萃取剂的回收利用率可达94．25％以上。     

Arsenic contaminated site at an abandoned copper smelter plant: waste characterization and solidification/stabilization treatment

A preliminary survey of an arsenic contaminated site from an abandoned copper smelting facility and feasibility study of using solidification/stabilization (S/S) process to treat the contaminant waste were undertaken. It was found that the waste, located in the three-flue gas discharge tunnels, contained 2-40% arsenic. The pH of the contaminated waste is extremely low (ranging from 1.8 to 3.6). The X-ray diffraction evidence indicates that the arsenic particles present in the flue gas mainly exist as As(III), or As(2)O(3). The total amount of arsenic contaminated waste is estimated to be 700 ton in the studied area. About 50% of the particle sizes are less than 2 mm. Arsenic is easily extracted from wastes with a variety of leaching solutions. In order to meet the arsenic leaching standard of the toxicity characteristic leaching procedure (TCLP), an extremely high cement dosage is required in the S/S process (cement/waste weight ratio>6). The waste with lower particle size having higher specific surface area exhibits somewhat positive effect on the S/S performance. The use of fly ash from municipal waste incinerators, in conjunction with the reduced amount of cement, is able to meet the TCLP arsenic and lead standards. The use of lime alone could meet the TCLP arsenic standard, but lead leaching concentrations exceeded leaching Pb standard. The results of semi-dynamic leaching tests of some solidified samples indicate higher accumulated arsenic leaching concentrations after only a few leachant renewals.     

Measuring Inorganic and Alkyl Lead Emissions from Stationary Sources

Described are the results from studies done to provide test methods for state and local air pollution control agencies to measure accurately the lead emissions from stationary source stacks as required in the National Ambient Air Quality Standard for Lead. Separate test methods were developed for measuring inorganic lead and alkyl lead compounds. Inorganic lead is collected in a standard particulate sampling train, digested with 50% (V/V) nitric acid and 3% hydrogen peroxide and analyzed by atomic absorption spectrometry. Alkyl lead compounds are collected in iodine monochloride and analyzed by atomic absorption spectrometry without prior solvent extraction. Standard solutions of inorganic lead in dilute nitric acid are used to calibrate the spectrophotometer in both methods. The inorganic lead test method was evaluated using baghouse dust samples from a primary copper and a primary lead smelter and stack samples from a lead recovery furnace, a primary battery manufacturing plant, a gray iron foundry and a secondary lead smelter. The alkyl lead method was evaluated using alkyl lead motor mix fluids and samples from an alkyl lead manufacturing plant vent stack.     

Application of coupled thermostatted columns in civil engineering and for leaching heavy metals of wastes from foundry sands and mining industry

For many years, the mining industry at Pachuca Hidalgo, Mexico, has produced silver and gold through a cyanide process. Solid wastes (tailings) of this process have been deposited close to centres of population. Many of the metals in these wastes are dispersed via wind and rain, and can be toxic to flora and fauna. Foundry sands are wastes, produced by the automotive industry, the metallurgy industry and others, which are contaminated with many metals such as Fe, Cr, Zn, Pb, Au Ag, Ti, Ge, Co, As, Al, etc. We have previously patented a process for the extraction of toxic and valuable metals from foundry sands using a thermostatted column. The results of this study indicate that the process and the device could be used for removing heavy metals from tailings. In this research both types of waste (foundry sands and tailings) were leached using four coupled thermostatted columns. The presence of heavy metals in the solid wastes was studied using the ICP-AS technique and scanning electron microscopy, and to study the structure we used X-ray diffraction. After leaching we used the solid wastes (without toxic metals) to produce bricks. The mechanical properties of the bricks were assessed against international standards.     

废弃油基钻井液提取柴油剩余废弃物无害化处理研究

针对废弃油基钻井液中柴油回收过程产生的泥渣、废水、废白土和酸碱废渣具有高色度、高pH、高COD和高石油类的特点,通过优化实验得出了一步法无害化处理废弃混合物的最佳固化配方:水泥和粉煤灰加量分别为12.5%,激活剂SG加量1.5%,促凝剂LSL加量1.5%,石灰加量1%。在最佳固化配方下,固化体浸出液的各主要污染指标都符合《污水综合排放标准》(GB 8978-1996)一级标准,固化成本约100元/m3,与分别处理废渣、废液相比,其处理成本可降低约20%。     

Compressed air-assisted solvent extraction (CASX) for metal removal

A novel process, compressed air-assisted solvent extraction (CASX), was developed to generate micro-sized solvent-coated air bubbles (MSAB) for metal extraction. Through pressurization of solvent with compressed air followed by releasing air-oversaturated solvent into metal-containing wastewater, MSAB were generated instantaneously. The enormous surface area of MSAB makes extraction process extremely fast and achieves very high aqueous/solvent weight ratio (A/S ratio). CASX process completely removed Cr(VI) from acidic electroplating wastewater under A/S ratio of 115 and extraction time of less than 10s. When synthetic wastewater containing Cd(II) of 50mgl(-1) was treated, A/S ratios of higher than 714 and 1190 could be achieved using solvent with extractant/diluent weight ratio of 1:1 and 5:1, respectively. Also, MSAB have very different physical properties, such as size and density, compared to the emulsified solvent droplets, making separation and recovery of solvent from treated effluent very easy.     

Contaminants in waste foundry sand and its leachate

The environmental characteristics of Waste Foundry Sands (WFS), including chemicals in WFS and its leachate, are essential in understanding the environmental impact, rational disposal and potential development of beneficial applications of this solid industrial waste. This paper presents an assessment of broad-spectrum chemicals (metallic, non-metallic and organic chemicals) in aspects of their statistics (mean, median and the 95th percentile) in dry-weight WFS and WFS leachates based on laboratory measurements of 594 WFS samples from 123 foundry facilities in the USA. Results indicate that WFS is basically not hazardous except a risk associated with WFS from copper-based foundry facilities. Leachability of metallic chemicals varies among investigated WFS. A clear delineation between different leaching protocols is implicated.     

HISTORY of the Air Pollution Control Association

Bottom ash is a waste material from coal-fired power plants, and it is known to contain elements that are potentially toxic at high concentration levels when disposed in landfills. This study investigates the use of bottom ash as a partial substitute sorbent for wet flue gas desulfurization (FGD) processes by focusing on its leaching kinetics in adipic acid. This was studied basing on the shrinking core model that was applied to the experimental data obtained by the authors presented at the International Conference on Industrial, Manufacturing, Automation and Mechanical Engineering, Johannesburg, South Africa, November 27–28, 2013) on dissolution of bottom ash. The leaching rate constant was obtained from different reaction variables, namely, temperature, pH, acid concentration, and solid-to-liquid ratio, that could affect the leaching process. The solid sample of bottom ash was characterized at different leaching periods using X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that solid-to-liquid ratio had a significant effect on the leaching rate constant when compared with other variables. The leaching kinetics showed that diffusion through the product layer was the rate-controlling step during leaching, and the activation energy for the process was found to be 18.92 kJ/mol.

Implications:?The use of coal bottom ash waste as a sorbent substitute in wet flue gas desulfurization (FGD) has both economic and environmental advantages. This is because it is a waste from coal-fired thermal power plant and this study has proven that it can leach out a substantial amount of calcium ions for wet FGD process. This will abate anthropogenic pollution due to landfill disposal of bottom ash wastes and also reduce sulfur dioxide emissions.     

Static Leaching of Solidified/Stabilized Hazardous Waste from the Soliditech Process

WILT, ANS 16.1 and TCLP leach tests were performed on solidified/stabilized (s/s) wastes treated by Soliditech, Inc. of Houston, Texas as part of a U.S. EPA SITE demonstration project conducted in December 1988 at the Imperial Oil Company/ Champion Chemical Company Superfund site in Morganville, New Jersey. All three leaching tests performed on the s/s wastes indicated that the primary contaminants of concern (lead and PCBs) were not leachable. The ANS 16.1 static leach test for the s/s wastes provided diffusion coefficients (D_e) for Al, Ca, and Na that were comparable to those obtained from the WILT test. However, plots of the ANS 16.1 data indicated that wetting of the samples confounded the static leaching process. The large column WILT D_e was used to estimate that less than 0.8 μg/cm² lead would leach from a one-cubic yard block of s/s waste in contact with groundwater over a 60-month leaching period. This corresponds to concentrations less than 10 μg/L lead in the water contacting the block of s/s waste.     

Initiatives to reduce lead from electronic devices: evidence of success from the toxicity characteristic leaching procedure

Discarded electronic devices (E-waste) have historically been found to exceed US Toxicity Characteristic hazardous waste thresholds for lead. Research was conducted to assess whether global and national lead reduction initiatives in the past decade translate to reduced toxicity characteristic leaching procedure (TCLP) lead leaching from E-waste. Nine categories of devices were subjected to TCLP and in all devices except one (smoke detectors), mean TCLP lead concentration results decreased by an order of magnitude or more (to levels below regulation thresholds). Mean TCLP lead concentrations decreased from 29.1 mg/L (2000–2005) to 0.224 mg/L (2008+) for cell phones and 1.26 mg/L (2000–2005) to 0.060 mg/L (2008+) for PCs. Most recently manufactured electronic devices (of those types tested here) comply with the definition of non-hazardous waste under US regulations.

Implications: Discarded electronic devices (E-waste) have often been tested as hazardous waste in the US because of lead leaching. Toxicity characteristic leaching procedure (TCLP) testing on more recently manufactured devices reveals that global lead reduction efforts have resulted in newer devices complying with US non-hazardous waste definitions. While these results highlight the success of lead reduction efforts, they raise policy questions regarding how best to incentivize E-waste recycling going forward.     

Characterization of polycyclic aromatic hydrocarbons (PAHs) on lime spray dryer (LSD) ash using different extraction methods

In this study, traditional Soxhlet, automatic Soxhlet and ultrasonic extraction techniques were employed to determine the speciation and concentration of polycyclic aromatic hydrocarbons (PAHs) on lime spray dryer (LSD) ash samples collected from the baghouse of a spreader stoker boiler. To test the efficiencies of different extraction methods, LSD ash samples were doped with a mixture of 16 US EPA specified PAHs to measure the matrix spike recoveries. The results showed that the spike recoveries of PAHs were different using these three extraction methods with dichloromethane (DCM) as the solvent. Traditional Soxhlet extraction achieved slightly higher recoveries than automatic Soxhlet and ultrasonic extraction. Different solvents including toluene, DCM:acetone (1:1 V/V) and hexane:acetone (1:1 V/V) were further examined to optimize the recovery using ultrasonic extraction. Toluene achieved the highest spike recoveries of PAHs at a spike level of 10 microg kg(-1). When the spike level was increased to 50 microg kg(-1), the spike recoveries of PAHs also correspondingly increased. Although the type and concentration of PAHs detected on LSD ash samples by different extraction methods varied, the concentration of each detected PAH was consistently low, at microg kg(-1) levels.     

The digestibility of waste activated sludges.

Laboratory digestion studies using waste activated sludges (WAS) were conducted to compare the digestion performance between anaerobic and aerobic processes. Nine samples of WAS from seven wastewater treatment plants were collected and batch-digested under both anaerobic and aerobic conditions for 30 days at 25 degrees C. The cation content of wastewater (both floc and solution phases) and solution biopolymer (protein and polysaccharide) was measured before and after digestion and compared with volatile solids destruction data. The study revealed that each digestion process was associated with a distinct biopolymer fraction, which accounted for differences in volatile solids reduction under anaerobic and aerobic conditions. The anaerobic digestion data showed strong correlations between soluble protein generation, ammonium production, percent volatile solids reduction, and floc iron (Fe). These data suggest that the amount of volatile solids destroyed by anaerobic digestion depends on the Fe content of floc. In aerobic digestion, polysaccharide accumulated in solution along with calcium and magnesium. For aerobic digestion, correlations between divalent cation release and the production of inorganic nitrogen were found. This implies that divalent cation-bound biopolymer, thought to be lectin-like protein, was the primary organic fraction degraded under aerobic conditions. The results of the study show that the cation content in wastewater is an important indicator of the material that will digest under anaerobic or aerobic conditions and that some of the volatile solids will digest only under either anaerobic or aerobic conditions.     

水泥回转窑固化处理废弃重金属元素的实验研究

废弃的重金属化学试剂是一类危险的固体废物.通过在水泥回转窑中添加质量小于水泥质量的重金属化学试剂的实验研究表明(本实验添加质量约为水泥的0.1%):掺加化学试剂重金属元素后,各水泥熟料的XRD图谱相似,水泥熟料主要矿物相没有发生大的改变;重金属化学试剂的添加对水泥的7 d、28 d抗压强度的影响较小,符合国家标准;熟料试样在其水化28 d时各重金属的浸出量都很低,已低于工业固体废物浸出毒性鉴别标准规定的指标,由此表明利用水泥回转窑处理废弃化学试剂方法可行.     

硫酸锰废渣浸出毒性及淋溶特性研究

长沙市兴镇13家硫酸锰厂的生产废渣使当地的生态环境造受到了严重破坏。本文在废渣浸出毒性实验、渣柱淋滤实验以及废渣的全分析基础上,全面地研究了废渣的组成、浸出毒性大小以及在当地酸沉降条件下的淋滤特征,为其安全处置提供了理论基础。研究证明,废渣中重金属种类多、含量高,尤其是锰,高达138800mg/kg。渣的浸出毒性虽未达到国家规定的危险废物鉴别标准,但远超过了《污水综合排放标准》,其衰减可用负指数方程来描述。在酸雨淋溶下,渣中的锰离子会在短时期内大量释放后,维持在一相对较低水平长期释放,对环境威胁巨大。     

Gaseous ammonia uptake in compost biofilters as related to compost water content

Sewage sludge and yard waste compost were used as biofilter materials and tested with respect to their capacity for removing ammonia from air at different water contents. Ammonia removal was measured in biofilters containing compost wetted to different moisture contents ranging from air dry to field capacity (maximum water holding capacity). Filters were operated for 15 days and subsequently analyzed for NH3/NH4+, NO2-, and NO3-. The measured nitrogen species concentration profiles inside the filters were used to calculate ammonia removal rates. The results showed that ammonia removal is strongly dependent on the water content in the filter material. At gravimetric water contents below 0.25 g H2O g solids(-1) for the yard waste compost and 0.5 g H2O g solids(-1) ammonia removal rates were very low but increased rapidly above these values. The sewage sludge compost filters yielded more than twice the ammonia removal rate observed for yard waste compost likely because of a high initial concentration of nitrifying bacteria originating from the wastewater treatment process and a high airwater interphase surface area that facilitates effective ammonia dissolution and transport to the biofilm.     

Metal extraction by Arabidopsis halleri grown on an unpolluted soil amended with various metal-bearing solids: a pot experiment.

Most studies dealing with phytoremediation have considered metal extraction efficiency in relation to metal concentration of bulk soil samples or metal concentration of the soil solution. However, little is known about the effect of various metal-bearing solids on plant growth and metal extraction of hyperaccumulators. In this study, we investigated the ability of Arabidopsis halleri to grow and extract metals from different substrates consisting in an unpolluted soil amended with various metal-bearing solids collected in soils around a Zn smelter complex. The metal-bearing solids used as amendments were: fresh and decomposing organic residues in the soil, a soil clay fraction and two waste slags. Pure mono-metallic salt (ZnSO4) was also used. Two series of substrates were produced, one moderately polluted, and the other highly polluted. An additional substrate was formed by the unamended soil, and used as an unpolluted control. Zn, Cd, Cu, and Pb were measured in the substrates, and in the roots and shoots of A. halleri. The dry matter yield of A. halleri was shown not to depend on the nature of the metal-bearing solid used, except when Cu-toxicity was suspected. On highly-polluted substrates, Zn extraction by A. halleri depended on the nature of metal-bearing solids used, showing the following trend: pure mono-metallic salt > waste slags and soil clay fraction > fresh and decomposing organic matter. We explained these differences by the high solubility of Zn in the mono-metallic salt, whereas in the mineral metal-bearing solids and in both fresh and decomposing organic matter, Zn release required mineral weathering or organic matter mineralization, respectively. This work clearly showed that phytoremediation studies have to consider the nature of metal-bearing solids in contaminated soils to better predict the efficiency of plant extraction.     

Anaerobic codigestion of municipal, farm, and industrial organic wastes: a survey of recent literature.

Codigestion of organic wastes is a technology that is increasingly being applied for simultaneous treatment of several solid and liquid organic wastes. The main advantages of this technology are improved methane yield because of the supply of additional nutrients from the codigestates and more efficient use of equipment and cost-sharing by processing multiple waste streams in a single facility. Many municipal wastewater treatment plants (WWTPs) in industrialized countries currently process wastewater sludge in large digesters. Codigestion of organic wastes with municipal wastewater sludge can increase digester gas production and provide savings in the overall energy costs of plant operations. Methane recovery also helps to reduce the emission of greenhouse gases to the atmosphere. The goal of this literature survey was to summarize the research conducted in the last four years on anaerobic codigestion to identify applications of codigestion at WWTPs. Because the solids content in municipal wastewater sludge is low, this survey only focuses on codigestion processes operated at relative low solids content (slurry mode). Semi-solid or solid codigestion processes were not included. Municipal wastewater sludge, the organic fraction of municipal solid waste, and cattle manure (CAM) are the main wastes most often used in codigestion processes. Wastes that are codigested with these main wastes are wood wastes, industrial organic wastes, and farm wastes. These are referred to in this survey as codigestates. The literature provides many laboratory studies (batch assays and bench-scale digesters) that assess the digestibility of codigestates and evaluate the performance and monitoring of codigestion, inhibition of digestion by codigestates, the design of the process (e.g., single-stage or two-stage processes), and the operation temperature (e.g., mesophilic or thermophilic). Only a few reports on pilot- and full-scale studies were found. These evaluate general process performance and pretreatment of codigestates, energy production, and treatment costs.     

Water-extractable phosphorus in biosolids: implications for land-based recycling.

Phosphorus-based nutrient management will inevitably be required for land application of biosolids. Water-extractable phosphorus (WEP) in livestock manures is an indicator of phosphorus loss from agricultural watersheds and this study evaluated its use for biosolids. The WEP to total phosphorus percentage (PWEP) in 41 biosolids (representing a variety of wastewater and solids treatment processes) was compared to dairy and poultry manures and triple superphosphate fertilizer. The mean PWEP for conventionally treated and stabilized biosolids was 2.4%, which was significantly lower than inorganic fertilizer (85%), dairy manure (52%), and poultry manure (21%). Low biosolids PWEP is attributed to elevated aluminum and iron content from chemical additions during wastewater treatment and solids dewatering operations. Facilities using biological phosphorus removal had the highest mean biosolids PWEP (approximately 14%), whereas heat-dried biosolids had the lowest average PWEP (< approximately 0.5%). Paired samples of digested cake and the corresponding biosolids treated by processes to further reduce pathogens (i.e., thermal treatment, composting, and advanced alkaline stabilization) showed that these processes tended to reduce biosolids PWEP. Biosolids composition and processing mode exert a controlling influence on the potential for off-site phosphorus migration at land-application sites. Nutrient management policies for land-based recycling should account for the widely varying potential of organic amendments to cause soluble phosphorus losses in runoff and leaching.     

Flow Injection Analysis of MWC Fly Ash Leaching Characteristics

Abstract

A completely mixed batch reactor leaching method utilizing flow injection analysis (the CMBR-FIA method) was developed to study the lead leaching characteristics of municipal waste combustor fly ash. Flow injection analysis (FIA) coupled with atomic absorption spectrophotometry enabled the determination of lead concentrations at one minute intervals. The pH and oxidation-reduction potential of the solution were continuously monitored to characterize the leaching conditions. Automatic titration was used to alter the solution pH to defined endpoints. The CMBR-FIA method offers the ability to immediately observe alterations to the leaching solution, and grants the freedom to study a number of parameters concurrently. The CMBR-FIA method is a rapid and reliable means to investigate leaching characteristics. This paper describes the method and demonstrates its use to monitor the leaching of lead from municipal solid waste combustor fly ash as a function of pH. Soluble lead concentrations are shown to increase quickly with decreasing pH.

A maximum of 50% of the total lead concentration was available in solution at pH 2. This value gradually decreased with time to over 35% of the total.     

Process performance evaluation of the contact stabilisation system at Birzeit University

The purification capacity of the contact stabilisation system at Birzeit University campus has been studied for two years. The oxidation capacity of organic matter, ammonium oxidation, and denitrification potential were determined. The reduction of chemical oxygen demand (COD) was 85%, and the effluent COD concentration was less than 110 mg/l (the average value was 88 mg/l). Suspended solids were removed with equal efficiency. The aerobic stabilization of organic solids was efficient, and no excess biosolids (sludge) had to be removed. High nitrification (70% of the influent nitrogen were nitrified) could be maintained at 15°C, and 42% of the oxidised nitrogen was denitrified. The specific oxygenation capacity of the treatment system is relatively high and reached about 5 kwh/kg COD. The specific wastewater treatment cost is about 0.52 US$/m3 or about 58 US$ per population equivalent per year. Based on the results obtained, batch operation and intermittent aeration of the biological process are suggested to achieve high effluent quality and to reduce power consumption.