首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Modified atmosphere based on lack of O2 offers a safe, residue-free alternative to chemical fumigants for pest control in stored grains. In this study, we intended to determine whether elevated CO2 (at a biologically achievable level) has an enhanced suppressive effect over low O2 atmosphere alone on the cowpea bruchid (Callosobruchus maculatus), a storage pest of cowpea and other legumes. Experiments were performed under two modified atmospheric conditions, (1) 2% O2 + 18% CO2 + 80% N2 and (2) 2% O2 + 98% N2. Both hypoxic environments significantly affected the development and survival of all insect developmental stages. Eggs were most vulnerable to hypoxia, particularly at the early stage (4–6 h old), surviving only up to a maximum of 2 days in both treatments. These were followed by adults, pupae and larvae, in order of decreasing susceptibility. The 3rd and 4th instar larvae were most resilient to hypoxia and could survive up to 20 days of low O2. The presence of 18% CO2 significantly increased the mortality of adults, the later stage of eggs, as well as 1st and 4th instar larvae caused by hypoxia. However, the surviving insects exhibited faster development, evidenced by their earlier emergence from cowpea seeds compared to those without CO2. One interesting observation was the frequent, premature opening of the emergence windows in the 4th instar larvae when CO2 was involved. This phenomenon was not observed at all in insects stressed by low O2 alone. Differential expression profiling of metabolic genes and proteolytic activity of midgut digestive enzymes suggested that the rate of metabolic activity could contribute in part to the difference in insect development and survival under hypoxia in the presence and absence of CO2.  相似文献   

2.
Application of methoprene to fourth (penultimate) instar larvae of the silkworm Bombyx mori induced the appearance of the feeding dauer larvae at the fifth (last) instar and prevented pupal metamorphosis. Methoprene also increased the protein concentrations of hemolymph last instar larvae by preventing sequestration of storage proteins by the fat body. Usually, the female-specific storage protein 1 (SP1)* disappears from the male hemolymph at the time of the last larval instar. However, exposure of male larvae to methoprene at the penultimate instar enhanced the accumulation of SP1 in the hemolymph. The SP1 accumulated in males did not differ in molecular weight and immunoreactivity from the SP1 produced in female larvae. Both sexes of fourth instar larvae allatectomized on day 1 instantly accumulated SP1 in the hemolymph, and methoprene application after allatectomy suppressed the hemolymph accumulation of the SP1. In contrast, if allatectomy was carried out at a later stage of the fourth larval instar, SP1 concentration in hemolymph of fifth instar larvae did not increase, suggesting the different juvenile hormone action for regulation of SP1 synthesis in the penultimate instar larvae of silkworms.  相似文献   

3.
To establish a Bioregenerative Life Support System (BLSS) in lunar or Mars bases in the future, manned stimulation experiments including several kinds of creatures are needed to be conducted first. Gas exchange relation, element transfer and transformation principles, etc. between humans and the multibiological system composed of plants, animals, microalgae and so on must be investigated in order to place different organisms with appropriate numbers and proportions in the BLSS. This research cultivated lettuce (Lactuca sativa L.) and silkworm (Bombyx mori L.) in the CICS (Closed Integrative Cultivating System) of the IES (Integrative Experimental System) with Chlorella vulgaris cultivated in the PPB (Plate Photo Bioreactor) of the IES. Conveyor-type cultivation method was implemented for harvesting the largest batch of lettuce and silkworms through the mass exchange chamber of the IES every four days and transferring the smallest batch of lettuce and silkworms into the system; carrying certain amounts of alga liquid out with nutrient liquid replenished every day. Gas exchange between testers and the IES including three phases was conducted periodically. Phase I involved one person participating in gas exchange with lettuce in plant chamber as primary means of air revitalization for 3 months. Phase II was gas exchange between one person and autotrophic creatures, which were lettuce and microalgae, for 1 month. In the Phase III test, silkworms were introduced into the animal chamber for 2 months. Mathematical modeling and experimental simulation for this system was done to study its gas robustness. Results show that CO2/O2 concentration fluctuated around normal levels, the system possessed relatively good gas robustness and there were no trace gas (CH4, NH3 and C2H4) contaminant problems in the system.  相似文献   

4.
Effects of different physical pretreatments on water hyacinth for dilute acid hydrolysis process (121 ± 3 °C, 5% H2SO4, 60 min) were comparatively investigated. Untreated sample had produced 24.69 mg sugar/g dry matter. Steaming (121 ± 3 °C) and boiling (100 ± 3 °C) for 30 min had provided 35.9% and 52.4% higher sugar yield than untreated sample, respectively. The highest sugar yield (132.96 mg sugar/g dry matter) in ultrasonication was obtained at 20 min irradiation using 100% power. The highest sugar production (155.13 mg sugar/g dry matter) was obtained from pulverized samples. Hydrolysis time was reduced when using samples pretreated by drying, mechanical comminution and ultrasonication. In most methods, prolonging the pretreatment period was ineffective and led to sugar degradations. Morphology inspection and thermal analysis had provided evidences of structure disruption that led to higher sugar recovery in hydrolysis process.  相似文献   

5.
In this study, silkworm moth (Bombyx mori L.) larvae were regarded as an animal protein source for astronauts in the bioregenerative life support system during long-term deep space exploration in the future. They were fed with mulberry and stem lettuce leaves during the first three instars and the last two instars, respectively. In addition, this kind of environmental approach, which utilised inedible biomass of plants to produce animal protein of high quality, can likewise be applied terrestrially to provide food for people living in extreme environments and/or impoverished agro-ecosystems, such as in polar regions, isolated military bases, ships, submarines, etc. Respiration characteristics of the larvae during development under two main physiological conditions, namely eating and not-eating of leaves, were studied. Nutrient compositions of silkworm powder (SP), ground and freeze-dried silkworms on the 3rd day of the 5th instar larvae, including protein, fat, vitamins, minerals and fatty acids, were measured using international standard methods. Silkworms' respiration rates, measured when larvae were eating mulberry leaves, were higher than those of similar larvae that hadn't eaten such leaves. There was a significant difference between silkworms fed on mulberry leaves and those fed on stem lettuce in the 4th and 5th instars (P<0.01). Amounts of CO2 exhaled by the silkworms under the two physiological regimes differed from each other (P<0.01). There was also a significant difference between the amount of O2 inhaled when the insects were under the two physiological statuses (P<0.01). Moreover, silkworms' respiration quotient under the eating regime was larger than when under the not-eating regime. The SP was found to be rich in protein and amino acids in total; 12 essential vitamins, nine minerals and twelve fatty acids were detected. Moreover, 359?kcal could be generated per 100?gram of SP (dry weight).  相似文献   

6.
The capacity of hydrophobic octadecyl (C18) and SDR HyperD materials to remove the combination of 1% (v/v) solvent (tri-n-butyl phosphate, TnBP) with 1% (v/v) nonionic detergents (Triton X-100 and Triton X-45) used for viral inactivation of plasma-derived polyvalent intravenous immunoglobulin G (IVIG) preparation has been evaluated. Efficient removal of TnBP (<10 ppm in IVIG preparation) was found at ratios of 0.5 g of C18/7 ml of IVIG and 0.22 g of dry SDR HyperD/7 ml of IVIG. Binding capacities of TnBP were greater than 140 mg/g of C18 and greater than 318 mg/g of dry SDR HyperD. Complete removal of Triton X-45 (<2 ppm) was obtained at ratios of 1 g of C18/7 ml of IVIG and 0.44 g of dry SDR HyperD/7 ml of IVIG or above, corresponding to binding capacities in excess of 70 mg/g of C18 and in excess of 159 mg/g of dry SDR HyperD. Residual Triton X-100 was less than 30 ppm at a ratio of 4 g/14 ml of immunoglobulin G (IgG) for the C18 sorbent. Triton X-100 was less than 10 ppm when using SDR HyperD at a ratio of 0.66 g/7 ml of IgG, corresponding to a binding capacity of approximately 106 mg of Triton X-100/g of dry SDR HyperD. Good recoveries of IVIG were achieved in the effluent from both sorbents.  相似文献   

7.
Olive pomace was composted by using a reactor for a period of 50 days in four bioreactors. Urea was added to adjust C/N ration between 25–30. At the end of 50 days of composting using Trichoderma harzianum and Phanerochaete chrysosporium, cellulose and lignin were highly degraded. It was found that after 30 days, P. chrysosporium and T. harzianum degraded approximately 71.9% of the lignin and 59.25% of the cellulose, respectively. The percent of ash content in the raw waste mixture was 13%. This percentage increased from 13% to 18.55% in treatment bioreactors and from 13% to 13.55% in control reactors during 50 day of composting process. The amount of CO2 produced by the treated sample was 3 mg of CO2/g organic carbon which is indicated that the treated sample was considered as stable compost. The results proved that the use of accelerating agents was found to be efficient in producing mature stable with nearly non-phytotoxicity compared to control sample in less than 50 days.  相似文献   

8.
Rasineni GK  Guha A  Reddy AR 《Plant science》2011,181(4):428-438
The photosynthetic response of trees to rising CO2 concentrations largely depends on source-sink relations, in addition to differences in responsiveness by species, genotype, and functional group. Previous studies on elevated CO2 responses in trees have either doubled the gas concentration (>700 μmol mol−1) or used single large addition of CO2 (500-600 μmol mol−1). In this study, Gmelina arborea, a fast growing tropical deciduous tree species, was selected to determine the photosynthetic efficiency, growth response and overall source-sink relations under near elevated atmospheric CO2 concentration (460 μmol mol−1). Net photosynthetic rate of Gmelina was ∼30% higher in plants grown in elevated CO2 compared with ambient CO2-grown plants. The elevated CO2 concentration also had significant effect on photochemical and biochemical capacities evidenced by changes in FV/FM, ABS/CSm, ET0/CSm and RuBPcase activity. The study also revealed that elevated CO2 conditions significantly increased absolute growth rate, above ground biomass and carbon sequestration potential in Gmelina which sequestered ∼2100 g tree−1 carbon after 120 days of treatment when compared to ambient CO2-grown plants. Our data indicate that young Gmelina could accumulate significant biomass and escape acclimatory down-regulation of photosynthesis due to high source-sink capacity even with an increase of 100 μmol mol−1 CO2.  相似文献   

9.
Microwave-assisted ammonium hydroxide (NH4OH) followed by phosphoric acid (H3PO4) treatments were used to release monomeric sugars from Miscanthus sinensis grown in Cha-Chueng-Sao province, Thailand. Treatment with 1.0% (w/v) NH4OH, 15:1 liquid-to-solid ratio (LSR) at 120 °C temperature for 15 min liberated 2.9 g of monomeric sugars per 100 g of dried biomass, whereas the corresponding yield for a treatment with 1.78% v/v H3PO4, 15:1 LSR at 140 °C for 30 min was 62.3 g/100 g. The two-stage pretreatment, treatment with NH4OH at 120 °C temperature for 15 min followed by treatment with H3PO4 at 140 °C for 30 min, impressively provided the highest total monomeric sugar yield of 71.6 g/100 g dried biomass.  相似文献   

10.
By exposing Spodoptera litura Fabricius larvae to nickel (Ni) in artificial diets for successive three generations, we investigated the impacts of the dietary Ni on growth and immune response of the fifth and sixth instar larvae at 24 h intervals. The time of newly moulted fifth instar larvae was labelled as 0 h. After exposure to 5 mg/kg Ni for two generations, Ni exposure significantly improved larval phenoloxidase activity and encapsulation grade in fifth instar larvae when compared to controls, except for encapsulation grade at 72-120 h in the second generation. However, higher concentrations of Ni (≥10 mg/kg) only significantly reduced encapsulation grade at 72-120 h. In the third generation, insects given higher dietary levels of Ni (≥10 mg/kg) showed lower immune responses and retarded relative growth rate (RGR) compared to controls, but those exposed to lower Ni levels (≤5 mg/kg) had a significantly improved encapsulation grade at 24-72 h. Larvae at lower Ni level (≤5 mg/kg) treatments had significantly higher RGR in comparison with that in controls. There was no significant difference in food relative consumption rate (RCR) and RGR among any treatment of the fifth instar larvae in three successive generations. These results indicated that the type and extent of effects on growth and immune responses of S. litura varied with the Ni concentrations and exposure periods.  相似文献   

11.
Carboxymethyl cellulose was prepared using a continuous, reduced solvent, reactive extrusion process with a short reaction time. The effects of the amounts of NaOH (30 g, 40 g and 50 g), water:ethanol ratio (100%, 70%, 50%, 30% and 10% H2O) and their interactions on the physical, chemical and morphological properties of carboxymethyl cellulose were studied. Experiments were conducted using to a 5 × 3 blocked factorial design. X-ray diffraction analyses revealed higher degrees of crystallinity and fractions of cellulose-II crystalline structure when 100% H2O was used as compared to that for 70%, 50%, 30% and 10% H2O and a commercially available brand of carboxymethyl cellulose, AQUASORB A500. Statistical analysis revealed a significant interaction between the effects of NaOH and H2O on the degrees of substitutions. The degrees of substitutions decreased with increasing amounts of NaOH and tended to increase with increasing alcohol concentrations. Liquid uptake measurements revealed that the extent of saline uptake, measured at intervals of 1 min, 5 min and 10 min, by carboxymethyl cellulose prepared with 100% H2O, especially when 40 g and 50 g NaOH was used, was higher than that for 70%, 50%, 30% and 10% H2O and AQUASORB A500. This may have been because of the higher crystallinity in carboxymethyl cellulose prepared with 100% H2O. Carboxymethyl cellulose prepared with 70% H2O and 30 g and 50 g NaOH had the highest saline absorption, using the soak method, before and after centrifugation, respectively. Scanning electron microscopy for carboxymethyl cellulose prepared with 100% and 10% H2O, through images at 120X magnification, revealed fibers 100 μ to >800 μ in length and 0.8-3.3 μ in breadth. Some non fibrous particles, 0.8-6.7 μ in dimensions, also were observed for 100% H2O. Images at 900× magnification revealed partially damaged fiber surfaces.  相似文献   

12.
Endothelins (ETs), a family of vasoconstrictor peptides, are up-regulated in several pathological conditions in the brain, and induce astrocytic proliferation. We previously observed that ET-1 increased the expression of cyclin D1 protein. Thus, we confirmed the intracellular up-regulation of cyclin D1 by ET-1 in rat cultured astrocytes. Real-time PCR analysis indicated that ET-1 (100 nM) and Ala1,3,11,15-ET-1 (100 nM), a selective agonist of the ETB receptor, induced a time-dependent and transient increase in cyclin D1 mRNA. The effect of ET-1 was diminished by an ETB antagonist (1 μM BQ788) or inhibitors of Sp1 (500 nM mithramycin), ERK (50 μM PD98059), p38 (20 μM SB203580) and JNK (1 μM SP600125), but not inhibitors of NF-κB (10 μM SN50 and 100 μM pyrrolidine dithiocarbamate). The binding assay for Sp1 indicated that ET-1 increased the binding activity of Sp1 to consensus sequences, and two oligonucleotides of the cyclin D1 promoter including the Sp1-binding sites diminished the effect of ET-1. Western blot analysis showed that ET-1 induced time-dependent and transient phosphorylation of Sp1 on Thr453 and Thr739 via the ETB receptor. ET-1-induced phosphorylation of Sp1 was attenuated by PD98059 and SP600125. Additionally, ET-1 increased the incorporation of bromodeoxyuridine (BrdU) in cultured astrocytes and the number of BrdU-positive cells decreased in the presence of PD98059, SP600125 and mithramycin. These results suggest that ET-1 increases the expression of cyclin D1 via activation of Sp1 and induces astrocytic proliferation.  相似文献   

13.
A preliminary experiment was carried out to study the effect of dietary pyridoxine (PN) on thermal tolerance of Labeo rohita fingerlings exposed to endosulfan (1/10th 96 h LC50=0.2 ppb) stress, reared at 26.0±0.5 °C to assess its culture potential in different agro-climatic zones. Two hundred seventy fingerlings were randomly distributed into six treatment groups in triplicate. Five iso-caloric and iso-nitrogenous purified diets were prepared with graded levels of pyridoxine. Six treatment groups were T0 (10 mg PN+without endosulfan), T1 (0 mg PN+endosulfan), T2 (10 mg PN+endosulfan), T3 (50 mg PN+endosulfan), T4 (100 mg PN+endosulfan) and T5 (200 mg PN+endosulfan). After feeding for 60 days, critical temperature maxima (CTmax), lethal temperature maxima (LTmax), critical temperature minima (CTmin) and lethal temperature minima (LTmin) were determined in each group. There was significant (P<0.05) effect of dietary pyridoxine on temperature tolerance (CTmax, LTmax, CTmin and LTmin) of the groups fed diets supplemented with 100 and 200 mg PN/kg diet compared to other experimental groups. Positive correlations were observed between CTmax and LTmax (R2=0.85) as well as between CTmin and LTmin (R2=0.97). The effect was more prominent on lower thermal tolerance limit (CTmin and LTmin). The overall results obtained in this preliminary study indicated that pyridoxine supplementation at 100 mg PN/kg diet enhances the thermal tolerance of endosulfan exposed L. rohita fingerlings.  相似文献   

14.
The insertion reaction of maleic anhydride into the Cu-O bond in [CuOtBu] produced the complexes [Cu2(CO2C2H2CO2tBu)4 · dme] (1), [Cu(CO2C2H2CO2tBu)2 · tmeda] (2) and [Cu2(CO2C2H2CO2tBu)2 · dppm]2 (3) (dme = 1,2-dimethoxyethane; tmeda = N1,N1,N2,N2-tetramethylethane-1,2-diamine; dppm = bis(diphenylphosphino)methane). This reaction represents a useful synthetic strategy for a range of functionalised Cu(I) and Cu(II) carboxylates.  相似文献   

15.
Lead intoxication is usually insidious and may cause a variety of complications such as kidney damage and hypertension. The role of intrarenal renin-angiotensin system (RAS) in lead-induced nephropathy has not been investigated. Adult male Sprague-Dawley rats were fed with water containing 250 ppm of lead acetate (lead group) and deionized water (control group) for 4 weeks. Another two groups started to receive intraperitoneal captopril (50 mg/kg/d) or losartan (10 mg/kg/d) after 2 weeks of lead feeding and continued for another 2 weeks. Immunoblotting was used to analyze the protein amount of intrarenal RAS components and transforming growth factor-beta (TGF-β). Compared with control group, lead exposure resulted in increased proteinuria after 2-week treatment (4.2 ± 0.9 mg/100 g vs. 1.8 ± 0.8 mg/100 g, p < 0.05) and 4-week (5.2 ± 1.7 mg/100 g, p < 0.05). Serum creatinine level was increased (0.40 ± 0.2 vs. 0.3 ±.04 mg/dL, p < 0.05) and calculated glomerular filtration rate (GFR) was decreased (2.68 ± 1.03 vs. 3.37 ± 0.11 mL/min, p < 0.05). Intrarenal angiotensin converting enzyme (ACE), angiotensin II (ANG II), angiotensin II type 1 receptor (AT1R) and transforming growth factor–beta (TGF-β) were upregulated in lead group. Captopril and losartan administration reduced proteinuria significantly (3.0 ± 0.50 mg/100 g of captopril and 2.7 ± 0.4 mg/100 g of losartan group) and lowered systolic blood pressure when compared with lead group. Furthermore, serum creatinine levels and GFR were improved by RAS blockade. Captopril treatment significantly reduced protein abundance of ACE, ANG II, AT1R and TGF-β. Losartan treatment also decreased ANG II and TGF-β. We concluded that lead exposure elicited intrarenal RAS activation with associated proteinuria and impaired renal function. RAS blockade was effective in alleviating lead-associated kidney injury and lowering blood pressure.  相似文献   

16.
We investigated the in vivo effects of orally administered cariprazine (RGH-188; trans-N-{4-[2-[4-(2,3-dichlorophenyl)-piperazin-1-yl]-ethyl]-cyclohexyl}-N′,N′-dimethyl-urea), a D3/D2 dopamine receptor partial agonist with ∼10-fold preference for the D3 receptor. Oral bioavailability of cariprazine at a dose of 1 mg/kg in rats was 52% with peak plasma concentrations of 91 ng/mL. Cariprazine 10 mg/kg had good blood-brain barrier penetration, with a brain/plasma AUC ratio of 7.6:1. In rats, cariprazine showed dose-dependent in vivo displacement of [3H](+)-PHNO, a dopamine D3 receptor-preferring radiotracer, in the D3 receptor-rich region of cerebellar lobules 9 and 10. Its potent inhibition of apomorphine-induced climbing in mice (ED50 = 0.27 mg/kg) was sustained for 8 h. Cariprazine blocked amphetamine-induced hyperactivity (ED50 = 0.12 mg/kg) and conditioned avoidance response (CAR) (ED50 = 0.84 mg/kg) in rats, and inhibited the locomotor-stimulating effects of the noncompetitive NMDA antagonists MK-801 (ED50 = 0.049 mg/kg) and phencyclidine (ED50 = 0.09 mg/kg) in mice and rats, respectively. It reduced novelty-induced motor activity of mice (ED50 = 0.11 mg/kg) and rats (ED50 = 0.18 mg/kg) with a maximal effect of 70% in both species. Cariprazine produced no catalepsy in rats at up to 100-fold dose of its CAR inhibitory ED50 value. Cariprazine 0.02-0.08 mg/kg significantly improved the learning performance of scopolamine-treated rats in a water-labyrinth learning paradigm. Though risperidone, olanzapine, and aripiprazole showed antipsychotic-like activity in many of these assays, they were less active against phencyclidine and more cataleptogenic than cariprazine, and had no significant effect in the learning task. The distinct in vivo profile of cariprazine may be due to its higher affinity and in vivo binding to D3 receptors versus currently marketed typical and atypical antipsychotics.  相似文献   

17.
It is known that (−)-linalool is a competitive antagonist of NMDA receptors, which play a key role in the learning and memory processes; however, only a few studies have reported a possible interference of (−)-linalool in memory. The purpose of this study was to investigate the (−)-linalool effects on acquisition of short- and long-term memories through the objects recognition task, inhibitory avoidance test and habituation to a novel environment. Furthermore, the open field test was used to investigate the interference of (−)-linalool in motivation, locomotion and exploration by animals. Wistar male adult rats received an intraperitoneal injection (i.p.) of saline (NaCl 0.9%), tween 5% or (−)-linalool (50 or 100 mg/kg) before training in the tasks; MK-801 (0.1 mg/kg), a glutamate antagonist, was used as positive control. Short-term (STM) and long-term (LTM) memories were tested 1.5 and 24 h after training, respectively, in the inhibitory avoidance and recognition objects. The results suggested that (−)-linalool (as 50- and 100-mg/kg doses) impaired LTM acquisition, but not STM acquisition, in the object recognition task. In the inhibitory avoidance test, animals receiving linalool (both doses) showed impairment in acquisition of both memories measured. In the open field test, the animals that received (−)-linalool showed no significant difference in the crossings and latency to start the locomotion in any of the doses tested, although (−)-linalool 100 mg/kg reduced rearing behavior. When re-exposed to open field 24 h after training, the rats that received (−)-linalool 100 mg/kg showed no habituation. Taken together, these data suggested that (−)-linalool was able to impair the acquisition of memory in rats, which can be associated to (−)-linalool antagonist capacity as regards NMDA glutamatergic receptors, since other glutamate antagonists also seem to affect memory.  相似文献   

18.
This study examined the preparation of high-capacity silica supports containing immobilized protein G. A maximum content of 39 mg protein G/g silica was obtained when using 100 Å pore size silica, followed by 33 mg/g for 50 Å silica and 9.3-24 mg/g for 300-4000 Å silica. The surface coverage of protein G increased with pore size, with a maximum level of 0.037 μmol/m2 being obtained for 4000 Å silica. These supports gave comparable apparent activities (i.e., 30-47% binding to rabbit immunoglobulin G [IgG]), with the highest binding capacities (71-77 mg IgG/g silica) being obtained for 50-100 Å silica.  相似文献   

19.
Methane emissions from a full-scale A/A/O wastewater treatment plant   总被引:5,自引:0,他引:5  
Wang J  Zhang J  Xie H  Qi P  Ren Y  Hu Z 《Bioresource technology》2011,102(9):5479-5485
Methane (CH4) emissions from a full-scale anaerobic/anoxic/oxic (A/A/O) wastewater treatment plant (WWTP) (Jinan, China) were investigated during spring and summer of 2010. Results showed that the major emission sources of CH4 performed the following descending order: anaerobic tanks, oxic tanks, aerated grit chambers and sludge concentration tanks. The total annual fluxes of CH4 emissions from the Jinan WWTP were 1.69 × 104 kg yr−1, with the emission factors of per capita emissions of 11.3 g CH4 person−1 yr−1 and flow-based emissions of 1.55 × 10−4 g CH4 (L of wastewater)−1. The estimated source strength of methane for all WWTPs in China was 6.2 Gg yr−1 (1 Gg = 109 g). The most significant factors influencing methane emissions were dissolved oxygen concentration in aerated grit chamber and oxic tank and water temperature in high density settler tanks.  相似文献   

20.
Sulfidogenic fluidized bed treatment of real acid mine drainage water   总被引:1,自引:0,他引:1  
The treatment of real acid mine drainage water (pH 2.7-4.3) containing sulfate (1.5-3.34 g/L) and various metals was studied in an ethanol-fed sulfate-reducing fluidized bed reactor at 35 °C. The robustness of the process was tested by increasing stepwise sulfate, ethanol and metal loading rates and decreasing feed pH and hydraulic retention time. Highest sulfate reduction rate (4.6 g/L day) was obtained with feed sulfate concentration of 2.5 g/L, COD/sulfate ratio of 0.85 and HRT of 12 h. The corresponding sulfate and COD removal efficiencies were about 90% and 80%, respectively. The alkalinity produced in sulfidogenic ethanol oxidation neutralized the acidic mine water. Highest metal precipitation efficiencies were observed at HRT of 24 h, the percent metal removal being over 99.9% for Al (initial concentration 55 mg/L), Co (9.0 mg/L), Cu (49 mg/L), Fe (435 mg/L), Ni (3.8 mg/L), Pb (7.5 mg/L) and Zn (6.6 mg/L), and 94% for Mn (7.21 mg/L).  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号