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1.
This paper focused on the removal and transformation of the dissolved organic matter （DOM） in secondary effluent during the granular activated carbon （GAC） treatment. Using XAD-8/XAD-4 resins, DOM was fractionated into five classes： hydrophobic acid （HPO-A）, hydrophobic neutral （HPO-N）, transphilic acid （TPI-A）, transphilic neutral （TPI-N） and hydrophilic fraction （HPI）. Subsequently, the water quality parameters of dissolved organic carbon （DOC）, absorbance of ultraviolet light at 254 nm （UV-254）, specific ultraviolet light absorbance （SUVA） and trihalomethane formation potential （THMFP） were analyzed for the unfractionated and fractionated water samples. The results showed that the order of the DOC removal with respect to DOM fractions was observed to be HPI〉HPO-A〉HPO-N〉TPI-A〉TPI-N. During the GAC treatment, the THMFP of the unfractionated water samples decreased from 397.4 μg/L to 176.5 μg/L, resulting in a removal efficiency of 55.6%. The removal order of the trilaalomethanes （THMs） precursor was as follows： HPO-A〉TPI-A〉TPI-N〉HPO-N〉HPI. By the GAC treatment, the specific THMFP of HPO-A, TPI-A, TPI-N and the original unfractionated water samples had a noticeable decrease, while that of HPO-N and HPI showed a converse trend. The Fourier transform infrared （FTIR） results showed that the hydroxide groups, carboxylic acids, aliphatic C-H were significantly reduced by GAC treatment. 相似文献
2.
本文主要研究了给水管网生物稳定性的问题,分析了饮用水中评价生物稳定性的四项指标:可生物同化有机碳(AOc)、可生物降解溶解性有机碳(BDOC)、可生物利用磷(MAP)和总磷(TP),以及各指标的测定方法和应用,并且分析了给水管网中水温,自由余氯等因素对生物稳定性的影响. 相似文献
3.
A pilot-scale ultrafiltration membrane plant was set up for treating Luanhe River water with flocculating and precipitation process of waterworks.The aim is to investigate the variation and characteristics of natural organic matter and disinfection byproducts formation potential in the whole process in winter.The results show that dissolved organic matter(DOM),UV254,trihalomethanes formation potential(THMsFP) and haloacetic acids formation potential(HAAsFP) of Luanhe River water were mainly distributed in t... 相似文献
4.
设计了膜生物反应器 (MBR)与粉末活性炭 (PAC)联合使用的膜组合工艺 (PAC MBR)处理微污染地表水 ,并用分子量分析方法来考察PAC MBR组合工艺及各单元工艺对有机物的去除效果 .分析结果表明 ,由于原水中的小分子有机物难生物降解 ,该工艺出水有机物集中在小于 1k的分子量区间内 ,活性炭的投加能显著提高这部分有机物的去除率 .试验证明 ,PAC MBR工艺中生物处理与活性炭吸附互相促进 ,在稳定运行阶段对CODMn、UV2 54 、UV4 10 和氨氮的去除率分别达到 70 %、70 %、10 0 %和 92 % . 相似文献
5.
The effects of the concentration of dissolved total organic carbon(TOC),the TOC/Br-ratio,bromide ion levels,the chlorine to ammonia-N ratio(Cl:N),the monochloramine dose and the chlorine dose on the formation of trihalomethanes(THMs)(including chloroform,bromodichloromethane,chlorodibromomethane,and bromoform)from chlorination were investigated using aqueous humic acid(HA)solutions.The profile of the chloramine decay was also studied under various bromide ion concentrations.Monochloramine decayed in the presence of organic material and bromide ions.The percentage of chloroform and brominated THMs varied according to the TOC/Br-ratio.Total THMs(TTHMs)formation increased from 112 to 190 μg/L with the increase concentrations of bromide ions from 0.67 to 6.72 mg/L,but the chlorine-substituted THMs were replaced by bromine-substituted THMs.A strong linear correlation was obtained between the monochloramine dose and the formation of THMs for Cl:N ratios of 3:1 and 5:1.These ratios had a distinct effect on the formation of chloroform but had little impact on the formation of bromodichloromethane or chlorodibromomethane.The presence of bromide ions increased the rate of monochloramine decay. 相似文献
6.
Fertilization increases paddy soil organic carbon density 总被引：5，自引：0，他引：5
Shao-xian Wang Xin-qiang Liang Qi-xiang Luo Fang Fan Ying-xu Chen Zu-zhang Li Huo-xi Sun Tian-fang Dai Jun-nan Wan Xiao-jun Li 《Journal of Zhejiang University. Science. B》2012,13(4):274-282
Field experiments provide an opportunity to study the effects of fertilization on soil organic carbon (SOC) sequestration.
We sampled soils from a long-term (25 years) paddy experiment in subtropical China. The experiment included eight treatments:
(1) check, (2) PK, (3) NP, (4) NK, (5) NPK, (6) 7F:3M (N, P, K inorganic fertilizers+30% organic N), (7) 5F:5M (N, P, K inorganic
fertilizers+50% organic N), (8) 3F:7M (N, P, K inorganic fertilizers+70% organic N). Fertilization increased SOC content in
the plow layers compared to the non-fertilized check treatment. The SOC density in the top 100 cm of soil ranged from 73.12
to 91.36 Mg/ha. The SOC densities of all fertilizer treatments were greater than that of the check. Those treatments that
combined inorganic fertilizers and organic amendments had greater SOC densities than those receiving only inorganic fertilizers.
The SOC density was closely correlated to the sum of the soil carbon converted from organic amendments and rice residues.
Carbon sequestration in paddy soils could be achieved by balanced and combined fertilization. Fertilization combining both
inorganic fertilizers and organic amendments is an effective sustainable practice to sequestrate SOC. 相似文献
7.
8.
The effects of the concentration of dissolved total organic carbon (TOC), the TOC/Br- ratio, bromide ion levels, the chlorine to ammonia-N ratio (Cl:N), the monochloramine dose and the chlorine dose on the formation of trihalomethanes (THMs) (including chloroform, bromodichloromethane, chlorodibromomethane, and bromoform) from chlorination were investigated using aqueous humic acid (HA) solutions. The profile of the chloramine decay was also studied under various bromide ion concentrations. Monochloramine decayed in the presence of organic material and bromide ions. The percentage of chloroform and brominated THMs varied according to the TOC/Br- ratio. Total THMs (TTHMs) formation increased from 112 to 190 μg/L with the increase concentrations of bromide ions from 0.67 to 6.72 mg/L, but the chlorine-substituted THMs were replaced by bromine-substituted THMs. A strong linear correlation was obtained between the monochloramine dose and the formation of THMs for Cl:N ratios of 3:1 and 5:1. These ratios had a distinct effect on the formation of chloroform but had little impact on the formation of bromodichloromethane or chlorodibromomethane. The presence of bromide ions increased the rate of monochloramine decay. 相似文献
9.
10.
A one-dimensional column is set up to study the mass transfer during air sparging process for methyl tertiary butyl ether(MTBE) removal in saturated soil and groundwater, with the condition of different airflow and soil penetrability. It is shown that the removal rate of MTBE can reach 80%, 90% and 95% when airflow is 0.05 m3/h, 0.085 m3/h and 0.10 m3/h, respectively. Increasing airflow will help to increase the removal rate of dissolved MTBE, but eventually a threshold removal rate is reached, above which further increasing air injection rates does not increase the removal rate. Fine sand allows the injected air to travel in bubble form, while coarse sand and medium sand allow the injected air to travel in the form of discrete channels; the greater the soil grain size is, the more extensive the channel net work forms, which in turn leads to higher removal rate. A tailing effect of lingering residual contaminant concentrations occur within the fine sand. About 20% of MTBE cannot be removed. 相似文献
11.
12.
Ridge culture is a special conservation tillage method, but the long-term influence of this tillage system on soil aggregate-size stability in paddy fields is largely unknown in southwest of China. The paper is to evaluate soil aggregate stability and to determine the relationship between soil organic carbon （SOC） and soil aggregate stability. Soil samples at 0 cm-20 cm layer were adopted from a long-term （16 a） field experiment including conventional tillage： plain culture, summer rice crop and winter upland crop under drained conditions （PUR-r）; and conservation tillage： ridge culture without tillage, summer rice and winter fallow with floodwater layer annually （NTR-f）, winter upland crop under drained conditions （NTR-r）, and wide ridge culture without tillage, summer rice crop and winter upland crop under conditions （NTRw-r）, respectively. Different pretreatments, such as slaking in fast wetting, wetting and subsequent slaking, were applied to simulate the breakdown mechanisms of aggregates in paddy soil. The results show that soil particles contents were mainly consisted of silt （0.050 mm to 1.000 mm） in fraction of 42.9% to 51.2%, sand （0.050 mm to 0.001 mm） in fraction of 28.0% to 31.8%, and clay （〈0.001 mm） in fraction of 17.9% to 25.4%. The amount of aggregate-size was greatly observed in fraction of 2.000 mm-6.720 mm under ridge culture in paddy soil （more than 50$） under slaking and wetting pretreatment. The proportion of soil macro-aggregates （〉0.250 mm） in conservation tillage was greatly higher than that in conventional tillage under subsequent fast slaking treatment. Minimal differences of aggregate stability between slaking in fast wetting and wetting were observed, while significant differences were found between ridge culture and plain culture. The aggregate stability under slaking treatment ranked in the order of NTR-r〉NTRw-r〉 NTR-f 〉 PUR-r, while under wetting was NTRw-r 〉 NTR-r 〉 NTR-f 〉PUR-r. There was a positive correlation between the aggregate stability and SOC concentration under wetting, and a low correlation was observed under slaking pretreatment. Soil exposure with tillage and lack of rice/rape-seed stubble inputs caused declines in aggregation and organic carbon, both of which make soil susceptible to water erosion. Adoption of ridge culture with no-tillage integrated with crop rotation and stubble mulch significantly altered soil organic concentration. It was a valuable conservation practice for soil aggregation and soil organic carbon sequestration on paddy soil. 相似文献
13.
The simultaneous removal of ethyl acetate, benzene and toluene with relatively low or high initial concentration is studied using a laboratory scale gliding arc gas discharge （GA） reactor. Good decomposition efficiencies are obtained which proves that the GA is effective for the treatment of volatile organic compounds （VOCs） with either low or high concentration. A theoretical decomposition mechanism is proposed based on detection of the species in the plasma region and analysis of the decomposition by-products. This preliminary investigation reveals that the GA has potential to be applied to the treatment of exhaust air during color printing and coating works, by either direct removal or combination with activated carbon adsorption/desorption process. 相似文献
14.
Combined treatment of landfill leachate with fecal supernatant in sequencing batch reactor 总被引：2，自引：1，他引：1
A laboratory-scale sequencing batch reactor （SBR） is used to treat landfill leachate containing high concentration of ammonium nitrogen with municipal fecal supernatant. The SBR system is operated in the following sequential phases： fill period, anoxic period, aeration period, settling period, decant and idle period. The results indicated that the average removal efficiencies of COD, BOD5, TN, NH4^＋-N were 93.76%, 98.28%, 84.74% and 99.21%, respectively. The average sludge removal loading rates of COD, BOD5, TN and NH4^＋-N were 0.24 kg/（kg SS.d）, 0.08 kg/（kg SS.d）, 0.04 kg/（kg SS.d） and 0.036 kg/（kg SS.d）, respectively. Highly effective simultaneous nitrification and denitrification was achieved in the SBR system. The ratio of nitrification and denitrification was 99% and 84%, respectively. There was partial NO2^- denitrification in the system. 相似文献
15.
INTRODUCTION Coking wastewater is generated in the produc- tion of coke, coal gas, tar and other coke by-products The coking wastewater includes inorganic pollutants such as ammonia, cyanogen, sulfocyan, heterocycle compounds and polycyclic aromatic compounds such as phenol, oils, naphthalene, pyridine, quinoline and anthracites, which are difficult to biodegradation under aerobic conditions (Ganczarczyk, 1972). Dis- charge of coking wastewater to the environment may cause severe contamin… 相似文献
16.
Wei-dong Guo Jun Liang Xiao-e Yang Yue-en Chao Ying Feng 《Journal of Zhejiang University. Science. B》2009,10(4):251-257
We studied the responses of the activities of adenosine-triphosphate (ATP) sulfurylase (ATPS) and serine acetyltransferase
(SAT) to cadmium (Cd) levels and treatment time in hyperaccumulating ecotype (HE) Sedum alfredii Hance, as compared with its non-hyperaccumulating ecotype (NHE). The results show that plant growth was inhibited in NHE
but promoted in HE when exposed to high Cd level. Cd concentrations in leaves and shoots rapidly increased in HE rather than
in NHE, and they became much higher in HE than in NHE along with increasing treatment time and Cd supply levels. ATPS activity
was higher in HE than in NHE in all Cd treatments, and increased with increasing Cd supply levels in both HE and NHE when
exposed to Cd treatment within 8 h. However, a marked difference of ATPS activity between HE and NHE was found with Cd treatment
for 168 h, where ATPS activity increased in HE but decreased in NHE. Similarly, SAT activity was higher in HE than in NHE
at all Cd treatments, but was more sensitive in NHE than in HE. Both ATPS and SAT activities in NHE leaves tended to decrease
with increasing treatment time after 8 h at all Cd levels. The results reveal the different responses in sulfur assimilation
enzymes and Cd accumulation between HE and NHE. With increasing Cd stress, the activities of sulfur assimilation enzymes (ATPS
and SAT) were induced in HE, which may contribute to Cd accumulation in the hyperaccumulator Sedum alfredii Hance.
Project supported by the National Natural Science Foundation of China (No. 30630046) and the Hi-Tech Research and Development
Program (863) of China (No. 2006AA06Z386), and the Program for Changjiang Scholars and Innovative Research Team in University,
China (No. IRT0536) 相似文献
17.
A treatability study of industrial wastewater containing chlorinated nitroaromatic compounds (CNACs) by a catalytic ozonation process (COP) with a modified Mn/Co ceramic catalyst and an aerobic sequencing batch reactor (SBR) was investigated.A preliminary attempt to treat the diluted wastewater with a single SBR resulted in ineffective removal of the color,ammonia,total organic carbon (TOC) and chemical oxygen demand (COD).Next,COP was applied as a pretreatment in order to obtain a bio-compatible wastewater for SBR treatment in a second step.The effectiveness of the COP pretreatment was assessed by evaluating wastewater biodegradability enhancement (the ratio of biology oxygen demand after 5 d (BOD5) to COD),as well as monitoring the evolution of TOC,carbon oxidation state (COS),average oxidation state (AOS),color,and major pollutant concentrations with reaction time.In the COP,the catalyst preserved its catalytic properties even after 70 reuse cycles,exhibiting good durability and stability.The performance of SBR to treat COP effluent was also examined.At an organic loading rate of 2.0 kg COD/(m3·d),with hydraulic retention time (HRT)=10 h and temperature (30±2) °C,the average removal efficiencies of NH3-N,COD,BOD5,TOC,and color in a coupled COP/SBR process were about 80%,95.8%,93.8%,97.6% and 99.3%,respectively,with average effluent concentrations of 10 mg/L,128 mg/L,27.5 mg/L,25.0 mg/L,and 20 multiples,respectively,which were all consistent with the national standards for secondary discharge of industrial wastewater into a public sewerage system (GB 8978-1996).The results indicated that the coupling of COP with a biological process was proved to be a technically and economically effective method for treating industrial wastewater containing recalcitrant CNACs. 相似文献
18.
Performance of biological phosphorus removal and characteristics of microbial community in the oxic-settling-anaerobic process by FISH analysis 总被引：1，自引：0，他引：1
Jian-fang Wang Qing-liang Zhao Wen-biao Jin Shi-jie You Jin-na Zhang 《浙江大学学报(A卷英文版)》2008,9(7):1004-1010
Performance of biological phosphorus removal in the oxic-settling-anaerobic （OSA） process was investigated. Cell staining and fluorescent in situ hybridization （FISH） were used to analyze characteristics and microbial community of sludge. Experimental results showed that phosphorus removal efficiency was near 60% and the amount of biological phosphorus accumulation in aerobic sludge of the OSA system was up to 26.9 mg/g. Biological phosphorus removal efficiency was partially inhibited by carbon sources in the continuous OSA system. Contrasted to the OSA system, biological phosphorus removal efficiency was enhanced by 14% and the average total phosphorus （TP） contents of aerobic sludge were increased by 0.36 mg/g when sufficient carbon sources were supplied in batch experiments. Staining methods indicated that about 35% of microorganisms had typical characteristics of phosphorus accumulating organisms （PAOs）. FISH analysis demonstrated that PAOMIX-binding bacteria were predominant microbial communities in the OSA system, which accounted for around 28% of total bacteria. 相似文献
19.
Wei-dong GUO Jun LIANG Xiao-e YANG Yue-en CHAO Ying FENG 《Journal of Zhejiang University. Science. B》2009,10(4)
We studied the responses of the activities of adenosine-triphosphate (ATP) sulfurylase (ATPS) and serine acetyl-transferase (SAT) to cadmium (Cd) levels and treatment time in hyperaccumulating ecotype (HE) Sedum alfredii Hance, as compared with its non-hyperaccumulating ecotype (NHE). The results show that plant growth was inhibited in NHE but promoted in HE when exposed to high Cd level. Cd concentrations in leaves and shoots rapidly increased in HE rather than in NHE, and they became much higher in HE than in NHE along with increasing treatment time and Cd supply levels. ATPS activity was higher in HE than in NHE in all Cd treatments, and increased with increasing Cd supply levels in both HE and NHE when exposed to Cd treatment within 8 h. However, a marked difference of ATPS activity between HE and NHE was found with Cd treatment for 168 h, where ATPS activity increased in HE but decreased in NHE. Similarly, SAT activity was higher in HE than in NHE at all Cd treatments, but was more sensitive in NHE than in HE. Both ATPS and SAT activities in NHE leaves tended to decrease with increasing treatment time after 8 h at all Cd levels. The results reveal the different responses in sulfur assimilation enzymes and Cd accumulation between HE and NHE. With increasing Cd stress, the activities of sulfur assimilation enzymes (ATPS and SAT) were induced in HE, which may contribute to Cd accumulation in the hyperaccumulator Sedum alfredii Hance. 相似文献
20.
Due to the importance of biological safety in drinking water quality and the disadvantages which exist in traditional methods of detecting typical microorganisms such as Cryptosporidium and Giardia, it is necessary to develop an alternative. Particle counts is a qualitative measurement of the amount of dissolved solids in water. The removal rate of particle counts was previously used as an indicator of the effectiveness of a biological activated carbon （BAC） filter in removing Cryptosporidium and Giardia. The particle counts in a BAC filter effluent over one operational period and the effects of BAC filter construction and operational parameters were investigated with a 10 m^3/h pilot plant. The results indicated that the maximum particle count in backwash remnant water was as high as 1296 count/ml and it needed about 1.5 h to reduce from the maximum to less than 50 count/ml. During the standard filtration period, particle counts stay constant at less than 50 count/ml for 5 d except when influenced by sand filter backwash remnant water. The removal rates of particle counts in the BAC filter are related to characteristics of the carbon. For example, a columned carbon and a sand bed removed 33.3% and 8.5% of particles, respectively, while the particle counts in effluent from a cracked BAC filter was higher than that of the influent. There is no significant difference among particle removal rates with different filtration rates. High post-ozone dosage （〉2 mg/L） plays an important role in particle count removal; when the dosage was 3 mg/L, the removal rates by carbon layers and sand beds decreased by 17.5% and increased by 9.5%, respectively, compared with a 2 mg/L dosage. 相似文献