Chlorobenzenes removal from municipal solid waste incineration fly ash by surfactant-assisted column flotation

The organic contaminants in municipal solid waste incineration (MSWI) fly ash, including chlorinated aromatic compounds and polycyclic aromatic hydrocarbons, have high toxicity and a potential negative impact on the environment. An effective and low energy consumption technique to remove the organic contaminants from MSWI fly ash is required urgently. Organic contaminants, such as chlorobenzenes (CBzs), in MSWI fly ash are known to become enriched in the unburnt carbon (UC) fraction. It is proposed that removal of UC from fly ash will result in the effective removal of most organic micropollutants. In this research, we use a technique of surfactant-assisted column flotation to decontaminate MSWI fly ash by removal of the CBzs-enriched UC from MSWI fly ash. We find that 39.8% of CBzs can be removed from fresh MSWI fly ash with 61.7% UC removal efficiency, whereas only 33.2% of CBzs can be removed from weathered MSWI fly ash with a low UC removal efficiency of 33.7%. By adding a mixture of two kinds of surfactants: sorbitan mono-oleate and polyoxyethylene (20) sorbitan mono-oleate to the weathered fly ash, 47.0% of CBzs were removed at the hydrophile lipophile balance value of 13.5, while the UC removal efficiency increased to 49.0%. The results show that surfactants can enhance CBzs and UC removal efficiencies during the column flotation process. Higher CBzs and UC removal efficiencies can be expected by further optimizing the conditions of surfactant-assisted column flotation.     

Aqueous leaching of cattle manure incineration ash to produce a phosphate enriched fertilizer

Ash produced from the combustion of livestock manure contains large amounts of phosphorus (P), which is an important resource as a fertilizer. Some studies have extracted and recovered P from incinerated biomass ash using inorganic acid or alkaline agents, which produce wastewater that requires treatment and is expensive due to the cost of chemicals. Livestock manure ash contains not only P, but also water soluble salts, which could be a negative influence on plant growth and shall be preferably removed from the recovered fertilizer. In this study, we removed salinity from cattle manure incineration ash by simple aqueous leaching, while retaining the P content. The optimal condition was a 20 min leaching time at a liquid/solid (L/S) ratio of 10 mL g-ash^?1. Under this condition, over 90 % of Cl and 20 % of Na in the original ash was removed, while over 99 % of the P was retained in the leached residue. The leached residue met the fertilizer standard in Japan in terms of citrate soluble fertilizer components and contained few heavy metals. X-ray analyses of the ash indicated that Cl was mainly present as KCl in the original ash, while P was mainly present as Ca compounds in the ash.     

Examination of in vivo mutagenicity of sodium arsenite and dimethylarsinic acid in gpt delta rats

Arsenic is a well-known human bladder and liver carcinogen, but its exact mechanism of carcinogenicity is not fully understood. Dimethylarsinic acid(DMAV) is a major urinary metabolite of sodium arsenite(i As~Ⅲ) and induces urinary bladder cancers in rats. DMAVand i As~Ⅲare negative in in vitro mutagenicity tests. However, their in vivo mutagenicities have not been determined. The purpose of present study is to evaluate the in vivo mutagenicities of DMAVand i As~Ⅲin rat urinary bladder epithelium and liver using gpt delta F344 rats.Ten-week old male gpt delta F344 rats were randomized into 3 groups and administered 0,92 mg/L DMAV, or 87 mg/L i As~Ⅲ(each 50 mg/L As) for 13 weeks in the drinking water. In the mutation assay, point mutations are detected in the gpt gene by 6-thioguanine selection(gpt assay) and deletion mutations are identified in the red/gam genes by Spi-selection(Spi-assay). Results of the gpt and Spi-assays showed that DMAVand i As~Ⅲhad no effects on the mutant frequencies or mutation spectrum in urinary bladder epithelium or liver. These findings indicate that DMAVand i As~Ⅲare not mutagenic in urinary bladder epithelium or liver in rats.     

Removal of unburned carbon from municipal solid waste fly ash by column flotation

Unburned carbon (UC) is the major source of organic contaminants in municipal solid waste (MSW) fly ash. So most organic contaminants can be removed by the removal of the UC from the MSW fly ash. In this paper, we first used a technique of column flotation to remove UC from MSW fly ash. The influences of column flotation parameters on the recovery efficiency of UC were systematically studied. It was found that the UC recovery efficiency was greatly influenced by the gas flow rate, pH value, collector kerosene's concentration and the types of fly ash. By optimizing the above parameters, we have successfully removed 61.2% of the UC from MSW fly ash having 5.24% UC content. The removal mechanism was well accounted for the kinetic theory of column flotation and surface-chemistry theory. The results indicate that the column flotation technique is effective in removing the UC from MSW fly ash, and show that there is a strong possibility for practical application of this technique in removing the organic contaminants from MSW fly ash.     

Evaluation of different sewage sludges as a potential biodiesel source in Japan

Journal of Material Cycles and Waste Management - Wastewater treatment plants (WWTPs) are producing and treating ever-larger quantities of sewage sludge as urban populations increase in size....     

Comparison of two types of municipal solid waste incinerator fly ashes with different alkaline reagents in washing experiments

In this study, we propose a "washing-calcination-conversion of washed fly ash into cement material with bottom ash" (WCCB) system to reduce the amount of fly ash that must be specially treated so it can be used as raw cement material. Calcium hydroxide (Ca(OH)2) is widely used in air-pollution control devices of incinerators while sodium bicarbonate (NaHCO3) is not. We conducted single-, double-, and triple-washing experiments to compare the washing characteristics of two types of fly ash. Unlike NaHCO3 fly ash, Ca(OH)2 fly ash has almost twice as much washed residue and almost 2.5 times more chlorine after the same washing procedure. After washing once, the washing frequency is also important for NaHCO3 fly ash, while the mixing time and liquid/solid ratio are more critical for Ca(OH)2 fly ash. The use of NaHCO3 is more suitable for the WCCB system.     

不同溶剂提取芦竹化感物质对铜绿微囊藻生长的影响

研究并比较了3种极性不同的有机溶剂(甲醇、乙酸乙酯、正己烷)提取的芦竹(Arundo donax Linn.)化感物质对铜绿微囊藻生长的影响.通过跟踪观察藻细胞形态,测定藻细胞密度和细胞大小,发现3种溶剂提取物对铜绿微囊藻均有抑制作用.抑藻作用出现早晚次序:甲醇提取物<乙酸乙酯提取物<正己烷提取物.随作用时间的延长,投加低浓度甲醇提取物藻细胞生长恢复明显,高浓度抑藻效果较乙酸乙酯提取物及正己烷提取物弱.高浓度乙酸乙酯提取物、正己烷提取物在分别作用2　d、 4 d　后,抑藻效果均接近100%.各溶剂提取物的半效应质量浓度(EC_50,6　d)分别为甲醇提取物0.17　 g·L^-1,乙酸乙酯提取物0.05 g·L^-1,正己烷提取物0.08 g·L^-1.研究同时发现,投加甲醇提取物藻细胞空洞化,投加乙酸乙酯提取物藻细胞空洞化、破碎以及部分抱团,投加正己烷提取物藻细胞出现褶皱及聚团现象.各溶剂提取物均引起铜绿微囊藻细胞体积减小,其中乙酸乙酯提取物的效果最强.     

Satellite Tracking of White-naped Crane Migration and the Importance of the Korean Demilitarized Zone

Satellite-tracking of 15 White-naped Cranes ( Grus vipio ) from their Japanese wintering grounds through the Korean Peninsula shows that there are four important regions for conserving migrant cranes: the Three Rivers Plain, the People's Republic of China; Lake Khanka, Russia; Kumya, North Korea; and—most importantly—the demilitarized zone of the Korean Peninsula. Two sites along the Korean demilitarized zone, Panmunch'om and Ch'olwon, were the most heavily used stopover sites, and they present complex international conservation challenges. Cranes stopped at these sites for up to 87.1% of their total migration time; cranes migrating to Zhalong Nature Reserve, China, made it their only lengthy stop. We report the migration routes and the importance of the identified stopover sites, and we outline conservation issues at those sites.     

烧结升温方式及气氛对水洗焚烧飞灰晶体演变的影响

为使水洗焚烧飞灰的稳定化处理进一步优化，探讨了热处理的加热过程、气氛条件等对水洗焚烧飞灰晶体成分演变的影响.同时也探讨了3种飞灰：锅炉飞灰（RFA）、CaO/Ca（OH）₂和NaHCO₃分别作为中和剂得到的两种飞灰（CaFA和NaFA）水洗后（RFA-II#、CaFA-II#和NaFA-II#）进行热处理比较.结果发现700℃是个转折点，从这个温度点开始3种水洗飞灰中的晶体成分发生明显变化；原位连续加热模式更容易形成固体溶液因而更适合重金属的稳定；NaFA-II#较之CaFA-II#更易于稳定重金属成分.Factsage的模拟结果与XRD结果一致，而且发现飞灰中氯化物在加热过程中首先释放的是HCl.     

Evaluation of metals in the residue of paper sludge after recovery of pulp components using an ionic liquid

The quantity of sludge produced by the paper industry in Japan in 2011 was estimated to be 27.91 million tons wet weight. This amount is the third largest among all industrial wastes. To explore ways of reusing recovered paper pulp and safely disposing of the residue, we investigated the distribution of metals in the process of recovery of pulp from two types of paper sludge using an ionic liquid. 32 and 46 % of pulp from paper sludge A and B was recovered using ionic liquid, respectively; the resultant weight reduction of the solid mass was comparable to that of incineration. There were virtually no heavy metals but aluminum in the recovered pulp, which makes its reuse viable at present. The characteristics of the metals in the residues differed according to the treatment used and properties of the paper sludge. Copper accounted for ~10 % in the ionic liquid used for recovery of pulp from the paper sludges. This suggests that [bmIm]Cl has the potential to dissolve a specific amount of copper compared to other metals.