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1.
关于进一步完善中国城市餐厨垃圾规范化回收体系的探讨   总被引:1,自引:0,他引:1  
中国现有的规范化餐厨垃圾回收体系的设计未能充分考虑目前城市餐厨垃圾回收的现实情况,从而导致回收体系出现结构上的残缺.通过实地调研与资料调研相结合的方法,系统梳理了中国城市餐厨垃圾回收体系的现状及存在的问题,并在此基础上从健全组织结构、建立合理的运行机制、建立适当的联系机制3个方面对已构建的规范化餐厨垃圾回收体系的进一步...  相似文献   

2.
餐厨垃圾发酵废液组分表征   总被引:1,自引:0,他引:1  
餐厨垃圾发酵废液是在利用餐厨垃圾发酵产乙醇的过程中蒸馏后产生的废液。为研究分析餐厨垃圾发酵废液的组成成分,利用国家标准方法对其常规水质指标、无机离子进行了检测,并利用三维荧光光谱技术和固相萃取—GC/MS技术对其有机物组分进行了分析。结果表明:餐厨垃圾发酵废液为SS=1 000 mg/L,COD=60 000 mg/L的高悬浮物、高浓度有机废液,TN和TP含量分别为700 mg/L和180 mg/L,废液可生化性好;其金属阳离子和无机阴离子以Na+、Cl-为主,浓度分别为1 200 mg/L和2 200 mg/L;有机物组分以芳香族蛋白质类物质为主,约占有机物总量的80%;在可挥发性有机组分中,餐厨垃圾发酵废液中以酸类和醇类物质为主,易于生物降解,且有可回收利用价值。  相似文献   

3.
分析了餐厨垃圾酸化过程中的pH、挥发性脂肪酸(VFA)产量及含水量等参数的变化,考察了酸化餐厨垃圾厌氧消化过程中的产氢情况,并探讨了调节初始pH对酸化餐厨垃圾产氢的影响.结果表明,餐厨垃圾的酸化是一个前期极为快速的过程,经过1d的酸化,新鲜餐厨垃圾的pH就从6.0左右下降到4.5左右,而后pH缓慢下降,经过5~6 d的酸化,pH下降到4.0以下;餐厨垃圾酸化过程中,产生的VFA主要是异戊酸,其浓度变化与VFA的浓度变化趋势较为一致;酸化时间为1、3、4、5、6d的餐厨垃圾体系产生的氢气的最高体积分数呈递减趋势,产氢量也呈现出相同的变化趋势;初始pH对酸化餐厨垃圾体系的产氢影响是很大的,调节到相同初始pH的不同体系,产氢的结果可以相近.因此,pH是酸化餐厨垃圾厌氧消化产氢过程中必须控制的关键因素之一.  相似文献   

4.
进行了餐厨垃圾(FW)和接种污泥(Ⅰ)基于不同VS比(分别为FW/I=1,FW/I=3,FW/I=5)下的中温厌氧消化实验,对比了不同有机负荷下未添加氧化铁和添加氧化铁对餐厨垃圾厌氧消化产气的影响。结果表明,在FW/I=1时,餐厨垃圾厌氧消化体系的产气情况主要由接种污泥决定,添加氧化铁仅能在较小的程度上促进体系产甲烷能力提升;而在FW/I=3时,添加氧化铁可以帮助餐厨垃圾厌氧消化体系从低速产甲烷过程快速进入高速产甲烷,快速降解有机质实现稳定化;而对于FW/I=5时添加氧化铁可以解除由于有机负荷过高造成的酸抑制并恢复体系的产甲烷能力。因此,在实际应用厌氧消化技术处理餐厨垃圾中可以通过添加氧化铁来提高其有机负荷(OLR),提高处理效率,保证餐厨垃圾厌氧消化的正常运行和促进甲烷的产生。  相似文献   

5.
在中试规模下,研究餐厨垃圾高温厌氧消化试验,通过监测餐厨垃圾厌氧消化过程中产气量、气体组成等产气情况和消化液中pH值、SCOD、NH4+-N、VFAs等化学指标含量变化,确定餐厨垃圾厌氧消化的最大有机负荷,并分析餐厨垃圾高温厌氧消化技术的可行性,结果表明,在工程上餐厨垃圾单独进行高温厌氧消化产甲烷具有技术可行性,但难以保证系统长时间安全稳定运行;餐厨垃圾厌氧消化正常运行时最大有机负荷可达2.551 kg VS/(m3.d);当系统有机负荷为2.551 kg VS/(m3.d)时,每天每千克VS最高可产生甲烷量0.622 m3;氨氮对餐厨垃圾厌氧消化产甲烷影响明显;餐厨垃圾中固有Na+含量对厌氧消化产甲烷影响不明显。  相似文献   

6.
竹叶与餐厨垃圾厌氧共消化工艺   总被引:1,自引:0,他引:1  
将黄金竹和毛竹的竹叶分别与餐厨垃圾厌氧共消化,通过分析消化过程中的产气量、pH、COD、NH4+-N和VFAs变化,探讨添加不同竹叶对餐厨垃圾厌氧消化效果的影响.实验结果表明,添加毛竹叶显著增强了餐厨垃圾的厌氧消化能力.毛竹叶+餐厨垃圾组的总产气量是餐厨垃圾对照组单独厌氧消化总产气量的3.28倍,甲烷总产量为10.1 L,COD去除率高达83.0%.而添加黄金竹叶对餐厨垃圾厌氧消化的影响则不明显,可能因为黄金竹叶在消化过程中释放了大量挥发性脂肪酸(VFAs),造成体系酸中毒.  相似文献   

7.
通过投加不同浓度的纳米零价铁(NZVI)和零价铁(ZVI),考察了暗发酵制氢过程中铁离子组成和浓度变化、氢化酶和脱氢酶活性,研究了2种添加剂强化餐厨垃圾高温((55±1)℃)暗发酵制氢的作用机制。结果表明:投加NZVI和ZVI均可提高餐厨垃圾暗发酵制氢性能;当投加100 mg·L~(-1) ZVI时,产氢效果最佳,最大产氢潜力和最大产氢速率分别为425.72 mL和66.32 mL·h~(-1),是投加NZVI实验组的1.64倍和1.34倍,代谢途径是以乙醇型发酵为主的混合型发酵;在投加NZVI和ZVI后,暗发酵制氢末端产物的Fe~(2+)和Fe~(3+)浓度升高,投加300 mg·L~(-1)NZVI和100 mg·L~(-1) ZVI实验组Fe2+浓度最大,是未投加实验组的2倍和1.87倍;与反应前相比,Fe~(2+)显著升高,Fe~(3+)由于微生物利用与转化浓度降低,同时可有效提高氢化酶活性。投加100 mg·L~(-1) ZVI不仅可提高氢化酶活性,还可提高脱氢酶活性。以上结果可为提高餐厨垃圾等复杂有机废物的高效能源化提供参考。  相似文献   

8.
餐厨垃圾中有机物大部分以大分子的形式存在,对其进行热处理,破坏大分子有机物的存在形式,将会影响其干式厌氧发酵的过程。实验对餐厨垃圾进行了热处理(100℃),处理后将其在含固率(TS)20%、接种率25%的条件下进行高温55℃厌氧发酵。实验结果表明,热处理后,餐厨垃圾的理化性质发生显著变化,累计产气量、TS和VS的去除率均增大。当热处理时间为15 min时,餐厨垃圾的SCOD值最高,为59.49 g/L,比未处理时提高了3.3倍。同样该条件下,累计产气量也最高,为2 782.8 m L,与未处理相比累积产气量提高58.30%,第二产气高峰比未处理提前3天。各发酵瓶发酵前后TS、VS去除率的变化趋势与累计产气量的变化基本一致,累计产气量越大,TS、VS的去除率越大。  相似文献   

9.
利用聚乙二醇(PEG)/葡聚糖(DEX)双水相体系分离餐厨垃圾发酵产物乳酸,分析了聚合物浓度和分子量的影响,以及餐厨垃圾多批次连续发酵时乳酸产率。实验结果表明,PEG/DEX双水相体系对乳酸菌生长影响不大,PEG和DEX浓度变化对乳酸产率、相体积比无显著影响;当DEX分子量由20 000升至40 000,乳酸生成速率由0.631 g/(L.h)降至0.518 g/(L.h),乳酸浓度由33 g/L降至22 g/L。多批次餐厨垃圾连续发酵可极大缩短发酵时间,在不投加缓冲剂的情况下,单批次乳酸产率仍大于0.30 g/g,累积产率大于0.45 g/g。  相似文献   

10.
城市餐厨垃圾前处理的工艺优化   总被引:1,自引:0,他引:1  
为提高餐厨垃圾资源化,利用自动化分选设备组合处理餐厨垃圾,考察餐厨垃圾快速减量化和资源化的可行性,对自动化分选前后餐厨垃圾成分进行分析,发现分选前其总量为243.05 t·d~(-1),TS为12.69%,VS为93.26%,分选后总量为242.00 t·d~(-1),TS为10.97%,VS为91.93%,其有机物含量稳定,利于厌氧发酵处理的工艺控制;对分选后餐厨垃圾进行厌氧发酵处理,考察其pH和NH_4~+-N变化,发现反应初期pH值出现弱酸性,NH_4~+-N浓度较低;随着反应进行,pH稳定在7.6~7.8,NH_4~+-N浓度约为1 200 mg·L~(-1)左右。最后对厌氧发酵产气量进行考察发现,反应前期受到pH、NH_4~+-N以及温度等反应条件影响,产气量和甲烷含量较低;随着实验趋于稳定,产气量为22 000 m3·d~(-1)左右,甲烷含量范围在65%~72%。结果表明,使用新型餐厨垃圾预处理设备,其分选效率较高,能提高后续厌氧发酵产气量和甲烷含量,较大程度实现餐厨垃圾资源化。  相似文献   

11.
Weathering of sulphide minerals produces a great variety of efflorescences of soluble sulphate salts. These minerals play an important role for environmental pollution, since they can be either a sink or a source for acidity and trace elements. This paper aims to characterise surface waters affected by mining activities in the Sierra Minera of Cartagena-La Union (SE, Spain). Water samples were analysed for trace metals (Zn, Cd, Pb, Cu, As and Fe), major ions (Na+, K+, Ca2+ and Mg2+) and anions (F?, Cl?, NO3 ?, CO3 2?, SO4 2?) concentrations and were submitted to an “evaporation-precipitation” experiment that consisted in identifying the salts resulting from the evaporation of the water aliquots sampled onsite. Mineralogy of the salts was studied using X-ray diffraction and compared with the results of calculations using VISUAL MINTEQ. The study area is heavily polluted as a result of historical mining and processing activities that has produced large amount of wastes characterised by a high trace elements content, acidic pH and containing minerals resulting from the supergene alteration of the raw materials. The mineralogical study of the efflorescences obtained from waters shows that magnesium, zinc, iron and aluminium sulphates predominate in the acid mine drainage precipitates. Minerals of the hexahydrite group have been quantified together with minerals of the rozenite group, alunogen and other phases such as coquimbite and copiapite. Calcium sulphates correspond exclusively to gypsum. In a semiarid climate, such as that of the study area, these minerals contribute to understand the response of the system to episodic rainfall events. MINTEQ model could be used for the analysis of waters affected by mining activities but simulation of evaporation gives more realistic results considering that MINTEQ does not consider soluble hydrated salts.  相似文献   

12.
In this study, fine particulate matter (PM2.5) emitted from a municipal solid waste incinerator (MSWI) was collected using dilution sampling method. Chemical compositions of the collected PM2.5 samples, including carbon content, metal elements, and water-soluble ions, were analyzed. Traditional in-stack hot sampling was simultaneously conducted to compare the influences of dilution on PM2.5 emissions and the characteristics of the bonded chemical species. The results, established by a dilution sampling method, show that PM2.5 and total particulate matter (TPM) emission factors were 61.6 ± 4.52 and 66.1 ± 5.27 g ton-waste?1, respectively. The average ratio of PM2.5/TPM is 0.93, indicating that more than 90% of PM emission from the MSWI was fine particulate. The major chemical species in PM2.5 included organic carbon (OC), Cl?, NH4+, elemental carbon (EC) and Si, which account for 69.7% of PM2.5 mass. OC was from the unburned carbon in the exhaust, which adsorbed onto the particulate during the cooling process. High Cl? emission is primarily attributable to wastes containing plastic bags made of polyvinyl chloride, salt in kitchen refuse and waste biomass, and so on. Minor species that account for 0.01–1% of PM2.5 mass included SO42-, K+, Na, K, NO3?, Al, Ca2+, Zn, Ca, Cu, Fe, Pb, and Mg. The mean ratio of dilution method/in-stack hot method was 0.454. The contents of water-soluble ions (Cl?, SO42-, NO3?) were significantly enriched in PM2.5 via gas-to-particle conversion in the dilution process. Results indicate that in-stack hot sampling would underestimate levels of these species in PM2.5.

Implications: PM2.5 samples from a municipal solid waste incinerator (MSWI) were collected simultaneously by a dilution sampling technique and a traditional in-stack method. PM2.5 emission factors and chemical speciation profiles were established. Dilution sampling provides more reliable data than in-stack hot sampling. The results can be applied to estimate the PM2.5 emission inventories of MSWI, and the source profile can be used for contribution estimate of chemical mass balance modeling.  相似文献   

13.

Zero-valent iron (Fe0) has been widely used for Cr(VI) removal; however, the removal mechanisms of Cr(VI) from aqueous solution under complex hydrogeochemical conditions were poorly understood. In this research, the mixed materials containing cast iron and activated carbon were packed in columns for the treatment of aqueous Cr(VI)-Cr(III) in groundwater with high concentration of Ca2+, Mg2+, HCO3 , NO3 , and SO4 2−. We investigate the influences of those ions on Cr(VI) removal, especially emphasizing on the reaction mechanisms and associated precipitations which may lead to porosity loss by using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) techniques. The results show that the precipitations accumulated on the material surface were (Fe/Cr) (oxy)hydroxide, mixed Fe(III)-Cr(III) (oxy)hydroxides, Fe2O3, CaCO3, and MgCO3. During these reactions, the Cr(VI) was reduced to Cr(III) coupled with the oxidated Fe0 to Fe(II) through the galvanic corrosion formed by the Fe0-C and/or the direct electron transfer between Fe0 and Cr(VI). In addition, Cr(VI) could be reduced by aqueous Fe(II), which dominated the whole removal efficiency. The primary aqueous Cr(III) was completely removed together with Cr(III) reduced from Cr(VI) even when Cr(VI) was detected in the effluent, which meant that the aqueous Cr(III) could occupy the adsorption sites. In general, the combined system was useful for the Cr(VI)-Cr(III) treatment based on galvanic corrosion, and the hardness ions had a negative effect on Cr(VI) removal by forming the carbonates which might promote the passivation of materials and decrease the removal capacity of the system.

  相似文献   

14.
Regeneration of iron for trichloroethylene reduction by Shewanella alga BrY   总被引:1,自引:0,他引:1  
Shin HY  Singhal N  Park JW 《Chemosphere》2007,68(6):1129-1134
Zero valent iron (ZVI), the primary reactive material in several permeable reactive barriers, is often oxidized to ferrous or ferric iron, resulting in decreased reactivity with time. Iron reducing bacteria can reconvert the ferric iron to its ferrous form, prolonging the reduction of chlorinated organic contaminants. In this study, the reduction of Fe(II,III) oxide and Fe(III) oxide by a strain of iron reducing bacteria of the group Shewanella alga BrY(S. alga BrY) was observed in both aqueous and solid phases. S. alga BrY preferentially reduced dissolved ferric iron over the solid ferric iron. In the presence of iron oxide the Fe(II) ions reduced by S. alga BrY efficiently reduced trichloroethylene (TCE). On the other hand, Fe(II) produced by S. alga BrY covered the reactive surfaces of ZVI iron filings and inhibited the reduction of TCE by ZVI. The formation of precipitates on the iron oxide or Fe0 surface was confirmed by scanning electron microscopy. The results suggest that iron-reducing bacteria in the oxidized Fe0 barriers can enhance the removal rate of chlorinated organic compounds and influence on the long-term performance of Fe0 reactive barriers.  相似文献   

15.
Zn/Fe体系湿法催化氧化高效脱除沼气中H2S的研究   总被引:2,自引:1,他引:1  
提出了Zn/Fe体系湿法催化氧化脱除沼气中H2S新工艺,阐述了反应机理、实验装置和工艺流程,考察了各单因素操作条件对H2S脱除效率的影响,在此基础上进行的综合条件实验,脱硫效率都维持在99.6%以上,净化后沼气中H2S含量低于国家标准。过程不消耗任何化工原料,不产生二次污染,体系无降解问题。  相似文献   

16.
ABSTRACT

Water is effective in leaching out Cr6+ from a mixture of paint powders and abrasive blast media. However, acids such as HNO3, HCl, and H2SO4 significantly enhance the leaching procedure. Cr ions in the leaching solutions are successfully removed by electrochemical precipitation. The consumable Fe electrodes generate ferrous ions to cause the reduction of Cr6+ to Cr3+. Cr3+ ions along with Fe2+ and Fe3+ are then removed mainly by precipitation as Cr(OH)3, Fe(OH)2, and Fe(OH)3 near the cathode where OH- ions are generated by water electrolysis. The electrochemical process is capable of discharging low levels of Cr6+, less than 1 mg/L, without pH adjustment.  相似文献   

17.
In the present study, selected advanced oxidation processes (AOPs)—namely, photo-Fenton (with Fe2+, Fe3+, and potassium ferrioxalate—FeOx—as iron sources), solar photo-Fenton, Fenton, and UV/H2O2—were investigated for degradation of the antineoplastic drug mitoxantrone (MTX), frequently used to treat metastatic breast cancer, skin cancer, and acute leukemia. The results showed that photo-Fenton processes employing Fe(III) and FeOx and the UV/H2O2 process were most efficient for mineralizing MTX, with 77, 82, and 90 % of total organic carbon removal, respectively. MTX probably forms a complex with Fe(III), as demonstrated by voltammetric and spectrophotometric measurements. Spectrophotometric titrations suggested that the complex has a 2:1 Fe3+:MTX stoichiometric ratio and a complexation constant (K) of 1.47 × 104 M–1, indicating high MTX affinity for Fe3+. Complexation partially inhibits the involvement of iron ions and hence the degradation of MTX during photo-Fenton. The UV/H2O2 process is usually slower than the photo-Fenton process, but, in this study, the UV/H2O2 process proved to be more efficient due to complexing of MTX with Fe(III). The drug exhibited no cytotoxicity against NIH/3T3 mouse embryonic fibroblast cells when oxidized by UV/H2O2 or by UV/H2O2/FeOx at the concentrations tested.  相似文献   

18.
The effects of the burning of fireworks on air quality in Beijing was firstly assessed from the ambient concentrations of various air pollutants (SO2, NO2, PM2.5, PM10 and chemical components in the particles) during the lantern festival in 2006. Eighteen ions, 20 elements, and black carbon were measured in PM2.5 and PM10, and the levels of organic carbon could be well estimated from the concentrations of dicarboxylic acids. Primary components of Ba, K, Sr, Cl, Pb, Mg and secondary components of C5H6O42−, C3H2O42−, C2O42−, C4H4O42−, SO42−, NO3 were over five times higher in the lantern days than in the normal days. The firework particles were acidic and of inorganic matter mostly with less amounts of secondary components. Primary aerosols from the burning of fireworks were mainly in the fine mode, while secondary formation of acidic anions mainly took place on the coarse particles. Nitrate was mainly formed through homogeneous gas-phase reactions of NO2, while sulfate was largely from heterogeneous catalytic transformations of SO2. Fe could catalyze the formation of nitrate through the reaction of α-Fe2O3 with HNO3, while in the formation of sulfate, Fe is not only the catalyst, but also the oxidant. A simple method using the concentration of potassium and a modified method using the ratio of Mg/Al have been developed to quantify the source contribution of fireworks. It was found that over 90% of the total mineral aerosol and 98% of Pb, 43% of total carbon, 28% of Zn, 8% of NO3, and 3% of SO42− in PM2.5 were from the emissions of fireworks on the lantern night.  相似文献   

19.
Sun Y  Takaoka M  Takeda N  Wang W  Zeng X  Zhu T 《Chemosphere》2012,88(7):895-902
An activated carbon (AC) containing a high concentration (374 mg g−1) of Fe was prepared by carbonization of an ion-exchange resin. To examine its chemical reactivity as a catalyst to decompose 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB-153), the decomposition parameters of temperature and time were varied under air or N2. Decomposition at 350 °C was achieved within 15 min under air and 30 min under N2, and the efficiency of PCB-153 decomposition was 99.7% and 98.0%, respectively. An analysis of inorganic chloride ions revealed that PCB-153 was mineralized effectively during the decomposition. The Brunauer-Emmett-Teller (BET) surface area and pore volume of the AC were measured to assess the adsorption capacity before and after the decomposition. The differences between decomposition under air and N2 reflected the differences in the BET surface and pore volume measurements. A decomposition pathway was postulated, and the reactive characteristics of chlorine atoms loaded on the benzene rings followed the order of para meta ortho, which agrees with the calculated results from a density functional theory study.  相似文献   

20.
Cheng WP 《Chemosphere》2002,47(9):963-969
Fluorescence quenching is commonly used to study the extent of metal binding to humic acid or fulvic acid. By studying this phenomenon, the hydrolysis and precipitation behaviors of polymeric and monomeric iron coagulants in the coagulation of humic acid were evaluated. Combined measurements of fluorescence intensity and dissolved organic carbon were performed to distinguish the hydrolysis and organic matter binding of polymeric and monomeric iron salts in coagulating high molecular weight organic compounds. Experimental results showed that ferric chloride had lower fluorescence quenching than polyferric sulfate (PFS), indicating more rapid hydrolysis of the monomeric ferric ion in the coagulation and dilution process. The less fluorescence quenching was caused by the lower residual concentration of Fe-humic acid complexes in the filtrate. There was no clear difference in adsorption ability and fluorescence quenching, which indicated that the physical and chemical properties of Fe(OH)3 flocs formed from PFS and FeCl3 coagulation were similar. From the pH study, we found that sludge formed from PFS coagulation was more stable than that from FeCl3 coagulation.  相似文献   

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