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661.
生物膜填料塔净化低浓度苯乙烯废气的实验研究 总被引:2,自引:0,他引:2
研究了进口气体中苯乙烯浓度、气体流量和液体流量等3个因素对生物膜填料塔净化苯乙烯废气的影响。研究结果表明,当进口气体中苯乙烯浓度为1000mg/m^3以下、气体流量为200L/h、循环液流量为10L/h的操作条件下,废气中苯乙烯的去除率可达90%以上。 相似文献
662.
针对我国采用高临界流动水分的磷矿进行湿法生产普钙普遍存在产品水分达不到部颁标准的难题,直接采用制浆废液(利用其主要对环境有害成分之一——MNA作减水剂)进行降低普钙水分的研究和应用.实验结果表明,添加少量的减水剂MNA可显著降低国内朝阳、昆阳、浏阳和国外摩洛哥等单种磷矿以及昆阳-朝阳混矿的矿浆粘度和水分.采用国产昆阳-朝阳混矿进行工业生产试验结果表明,添加0.35%~0.4%干矿粉重量的减水剂MNA,不仅可使球磨添加水量从145 kg降至103 kg,矿浆含水量从30.5%降至27%,成品肥含水量从16.24%降至13.77%,而且可使有效磷从10.67%升至12.24%,转化率由86.57%提高到90.45%,矿浆细度由90.18%提高到93.12%.实验和工业生产试验表明,直接用造纸制浆废液降低普钙水分,既确保和改善了普钙的产品质量,又治理了环境污染,取得了较好的经济、环境和社会效益. 相似文献
663.
人工湿地防治湖泊富营养化污染探讨 总被引:1,自引:0,他引:1
针对湖泊富营养化问题,结合抚仙湖当前污染状况,以马料河人工湿地为例,探讨利用人工湿地控制水体水质下降、脱氮除磷机理及其去除效率.结果显示:马料河人工湿地对TN、TP、SS的去除效率分别为:44.21%、46.03%、86.6%;其中TN的去除效率与进水流速具有一定的相关性;TP的去除效率相对稳定,去除机制主要与湿地基质有关. 相似文献
664.
Tian C Zhang Mohamed F Dahab Germana S Nunes Cong Hu Rao Surampalli 《Water environment research》2007,79(11):2343-2351
In this study, several columns of different lengths were filled with composite soils sampled from the field at corresponding depths and then loaded intermittently with influent of a high phosphorus concentration to evaluate phosphorus fate and transport in soil. The results indicate that the height of the mass transfer zone, solvent pore velocity, and soil's life expectancy for phosphorus removal increased with depth, while the retained phosphorus per kilogram of soil and the linear adsorption equilibrium coefficient, R, decreased with depth. An equation was developed to link liquid-phase phosphorus with solvent traveling time and soil depth. The results of X-ray diffraction and washout tests indicate that calcium-phosphorus precipitation and/or crystal growth occurred in the columns. The new protocol is useful for evaluation of phosphorus fate and transport in other subsurface systems, because it allows flexible adjustments in hydraulic loadings, feed solution, and sampling schemes. 相似文献
665.
666.
针对我国采用高临界流动水分的磷矿进行湿法生产普钙普遍存在产品水分达不到部颁标准的难题,直接采用制浆废液(利用其主要对环境有害成分之一--MNA作减水剂)进行降低普钙水分的研究和应用.实验结果表明,添加少量的减水剂MNA可显著降低国内朝阳、昆阳、浏阳和国外摩洛哥等单种磷矿以及昆阳-朝阳混矿的矿浆粘度和水分.采用国产昆阳-朝阳混矿进行工业生产试验结果表明,添加0.35%~0.4%干矿粉重量的减水剂MNA,不仅可使球磨添加水量从145 kg降至103 kg,矿浆含水量从30.5%降至27%,成品肥含水量从16.24%降至13.77%,而且可使有效磷从10.67%升至12.24%,转化率由86.57%提高到90.45%,矿浆细度由90.18%提高到93.12%.实验和工业生产试验表明,直接用造纸制浆废液降低普钙水分,既确保和改善了普钙的产品质量,又治理了环境污染,取得了较好的经济、环境和社会效益. 相似文献
667.
The organic precursors affecting the formation of disinfection by-products with chlorine dioxide 总被引:8,自引:0,他引:8
The object of this research was to study the formation of disinfection by-products by using chlorine dioxide (ClO2) as a disinfectant reacting with different properties of organic substance in natural aquatic environment. The adsorbent resin (XAD-4, XAD-7) was used to divide the organic matters in raw water into three groups. The influence of the function groups on structure, reaction tendency, and formation of disinfection by-products generated by the reaction of these organic substances with chlorine dioxide was explored. The experimental results show that the three different organic groups formed using adsorbent resin were hydrophobic substance, hydrophilic acid, and non-acid hydrophilics in proportions of 43%, 41%, and 16%, respectively. Within the raw water in our study, the hydrophilic substance had a higher distribution proportion than that described in general articles and journals, which indicates that this water was contaminated with pollution from human beings. The exploration of the reactivity of the three different organic substances with chlorine dioxide shows that the unit consumption of disinfection agent per unit organic matters (represented by ClO2/DOC) is in the following sequence hydrophobic substance > hydrophilic substance > non-acid hydrophilics. It indicated that larger molecular organic precursors had larger consumption of disinfectant. We also discovered that after the reaction of the three different organic substances with chlorine dioxide, the largest amount of disinfection by-products were generated by the non-acid hydrophilics. 相似文献
668.
Copper contamination in paddy soils irrigated with wastewater 总被引:19,自引:0,他引:19
Copper (Cu) contamination was investigated in paddy soils where Cu-rich wastewater (12 mg Cu/l) was used for irrigation. The results showed that Cu contamination increased the soil Cu content from 17.0 mg Cu/kg in the non-wastewater irrigated soils (NWIS) to 101.2 mg Cu/kg in the wastewater irrigated soils (WIS), and Cu accumulated mostly in the surface layer (0-10 cm) of the paddy soil. The average Cu contents in brown rice, rice hull and rice straw from NWIS were 1.4, 7.3 and 14.5 mg Cu/kg, while those from WIS were 15.5, 133.2, and 101.4 mg Cu/kg, respectively. Correlation analysis revealed that the relationship between the Cu content in the rice straw and the rice hull with the total Cu content of the soil could be described by an exponential function (R2 = 0.921 and 0.831, respectively; P <0.01). Rice plants grown in the WIS showed symptoms of black roots, less effective tiller, etc. Subsequently, the rice yield decreased by 18-25%, compared with that grown in NWIS. 相似文献
669.
Arbuscular mycorrhizae enhance metal lead uptake and growth of host plants under a sand culture experiment 总被引:2,自引:0,他引:2
A sand culture experiment was conducted to investigate whether mycorrhizal colonization and mycorrhizal fungal vesicular numbers were influenced by metal lead, and whether mycorrhizae enhance host plants tolerance to metal lead. Metal lead was applied as Pb(NO3)2 in solution at three levels (0, 300 and 600 mg kg(-1) sand). Five mycorrhizal host plant species, Kummerowia striata (Thunb.) Schindl, Ixeris denticulate L., Lolium perenne L., Trifolium repens L. and Echinochloa crusgalli var. mitis were used to examine Pb-mycorrhizal interactions. The arbuscular mycorrhizal inoculum consisted of mixed spores of mycorrhizal fungal species directly isolated from orchard soil. Compared to the untreated control, both Pb concentrations reduced mycorrhizal colonization by 3.8-70.4%. Numbers of AM fungal vesicles increased by 13.2-51.5% in 300 mg Pb kg(-1) sand but decreased by 9.4-50.9% in 600 mg Pb kg(-1) sand. Mycorrhizae significantly enhanced Pb accumulation both in shoot by 10.2-85.5% and in root by 9.3-118.4%. Mycorrhizae also enhanced shoot biomass and shoot P concentration under both Pb concentrations. Root/shoot ratios of Pb concentration were higher in highly mycorrhizal plant species (K.striata, I. denticulate, and E. crusgalli var. mitis) than that in poorly mycorrhizal ones (L. perenne and T. repens,). Mycorrhizal inoculation increased the root/shoot ratio of Pb concentration of highly mycorrhizal plant species by 7.6-57.2% but did not affect the poorly mycorrhizal ones. In the treatments with 300 Pb mg kg(-1) sand, plant species with higher vesicular numbers tended to show higher root/shoot ratios of the Pb concentration. We suggest that under an elevated Pb condition, mycorrhizae could promote plant growth by increasing P uptake and mitigate Pb toxicity by sequestrating more Pb in roots. 相似文献
670.