Membrane bioreactor process of organic wastewater from brassylic acid manufacturing plant

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｂｒａｓｓｙｌｉｃａｃｉｄｍａｎｕｆａｃｔｕｒｉｎｇｗａｓｔｅｗａｔｅｒｃｏｎｔａｉｎｓｈｉｇｈｃｈｅｍｉｃａｌｏｘｙｇｅｎｄｅｍａｎｄ(ＣＯＤ)ｃｏｎｃｅｎｔｒａｔｉｏｎ3000—12000ｍｇ/ＬａｎｄｉｔｓＢＯＤ5/ＣＯＤｉｓａｍｏｎｇ04—05Ｍｅａｎｗｈｉｌｅｔｈｅｗａｓｔｅｗａｔｅｒｃｏｎｔａｉｎｓｈｉｇｈｓｕｌｐｈａｔｅｃｏｎｃｅｎｔｒａｔｉｏｎａｂｏｕｔ13000ｍｇ/ＬａｎｄｉｔｓｐＨｖａｌｕｅｉｓｏｎｌｙ1—2Ａｃｈｅｍｉｃａｌｃｏｍｐａｎｙａｐｐｌｉｅｄｎｅｕｔｒａｌｉ…     

猪场废水厌氧发酵液循环脱氮工艺

研究了水解酸化与生物接触氧化组合循环工艺处理猪养殖场废水厌氧发酵液的脱氮特性,重点考察了组合工艺的最佳运行工况和参数,同时讨论了组合工艺低温运行的性能。结果表明,水力停留时间24 h和污水循环比1∶3为最佳运行工况,此时出水氨氮浓度为2.16～8.20 mg/L。溶解氧(DO)浓度2～3 mg/L和有机负荷3 g/L以下为最佳运行参数,出水氨氮浓度稳定在10 mg/L以下。在春季低温条件下(8～12℃),组合工艺也能较好运行,水解酸化池内小分子有机酸产生总量为114.50～244.22 mg/L。组合工艺连续运行3个月以上,污染物去除效果稳定。     

Comparison of different combined treatment processes to address the source water with high concentration of natural organic matter during snowmelt period

The source water in one forest region of the Northeast China had very high natural organic matter (NOM) concentration and heavy color during snowmelt period. The efficiency of five combined treatment processes was compared to address the high concentration of NOM and the mechanisms were also analyzed. Conventional treatment can hardly remove dissolved organic carbon (DOC) in the source water. KMnO₄ pre-oxidization could improve the DOC removal to 22.0%. Post activated carbon adsorption improved the DOC removal of conventional treatment to 28.8%. The non-sufficient NOM removal could be attributed to the dominance of large molecular weight organic matters in raw water, which cannot be adsorbed by the micropore upon activated carbon. O₃ + activated carbon treatment are another available technology for eliminating the color and UV₂₅₄ in water. However, its performance of DOC removal was only 36.4%, which could not satisfy the requirement for organicmatter. The limited ozone dosage is not sufficient to mineralize the high concentration of NOM. Magnetic ion-exchange resin combined with conventional treatment could remove 96.2% of color, 96.0% of UV₂₅₄ and 87.1% of DOC, enabling effluents to meet the drinking water quality standard. The high removal efficiency could be explained by the negative charge on the surface of NOM which benefits the static adsorption of NOM on the anion exchange resin. The results indicated that magnetic ion-exchange resin combined with conventional treatment is the best available technology to remove high concentration of NOM.     

Impact of litter removal on soil characteristics under a Pinus caribaea stand

ABSTRACT

Forest productivity is dependent on soil quality, which in turn is related to litter; yet there is limited understanding of the relationships between litter and soil quality. The effects of litter removal treatment on tree growth and soil properties were examined in a Pinus caribaea stand with the aim of providing an understanding of consequences of litter removal on soil patterns. This knowledge is important for planning appropriate long-term forest management. Three pairs of 30 × 30 m² plots (each pair a control and treatment) were established in the center of a P. caribaea stand in April 2002. The controls were left undisturbed with an intact litter layer, while litter was removed monthly from treated plots. The diameter and height of the P. caribaea decreased and soil quality was degraded over the experimental period in litter-removed (treated) plots. Litter removal also produced a significant increase in soil bulk density at 0–20 and 20–40 cm depths. The capillary porosity, capillary moisture capacity, and natural water content in controls at 0–20 and 20–40 cm depths were significantly greater than treated plots. The non-capillary porosity in controls at the 0–20 cm depth was also significantly higher than treated plots. The organic carbon, total nitrogen (N), total potassium (K) and alkalized N content in each layer, and available P and exchangeable K at 0–20 and 40–60 cm depths in control plots were significantly greater than litter-removed plots. The numbers of bacteria at 0–20 and 40–60 cm depths and of fungi at 20–40 and 40–60 cm depths were higher in control than treated plots. The number of actinomyces and urease, catalase, and acid phosphatase activities in controls at each depth were significantly greater than litter-removed plots.     

基于响应面法的污泥快速固化效能综合影响简

针对现有污泥固化技术存在的固化养护时间长、低温条件下固化效能低等问题。研究提出污泥快速（3 d）固化技术,采用响应曲面分析方法,重点考察了石灰、组分A、硅酸盐水泥、粉煤灰和温度等5因素对固化效能的综合影响,研究结果表明,石灰、组分A、硅酸盐水泥、粉煤灰和养护温度等因素对3 d固化体的无侧限抗压强度和含水率的线性效应显著,石灰和组分A、石灰和养护温度对无侧限抗压强度的交互影响显著,石灰和粉煤灰、组分A和养护温度、硅酸盐水泥和粉煤灰对含水率的交互影响显著;得出了5因素对固化体3 d无侧限抗压强度和含水率影响的定量模型,可对污泥快速固化进行优化和预测;并利用XRD和SED对污泥固化块的化学成分和微观结构进行了分析。     

Enhanced efficiency of cadmium removal by Boehmeria nivea (L.) Gaud. in the presence of exogenous citric and oxalic acids

Boehmeria nivea（L.） Gaud. is a potential candidate for the remediation of Cd contaminated sites. The present investigation aims to explore Cd tolerance threshold and to quickly identify the role of exogenous organic acids in Cd uptake and abiotic metal stress damage.Elevated Cd levels（0–10 mg/L） resulted in an obvious rise in Cd accumulation, ranging from268.0 to 374.4 in root and 25.2 to 41.2 mg/kg dry weight in shoot, respectively. Citric acid at1.5 mmol/L significantly facilitated Cd uptake by 26.7% in root and by 1-fold in shoot,respectively. Cd translocation efficiency from root to shoot was improved by a maximum of66.4% under 3 mmol/L of oxalic acid. Citric acid exhibited more prominent mitigating effect than oxalic acid due to its stronger ligand affinity for chelating with metal and avoiding the toxicity injury of free Cd ions more efficiently. The present work provides a potential strategy for efficient Cd remediation with B. nivea.     

硫脲法浸出回收炼锌废渣中的银

对用硫脲法从炼锌废渣中浸出回收银的工艺及其影响因素进行了研究;确定了最佳浸出工艺条件为：硫脲质量浓度１０ｇ／Ｌ,「Ｆｅ＾３＋」０．０１２５ｍｇ／Ｌ,液固比１０：１,浸出液ＰＨ１．５－２．０,浸出温度４０－６０℃;     

市场经济与宜宾经济发展战略

宜宾有丰富的自然资源,但至今经济仍然落后。本文剖析了这种既富饶又贫困的主要原因,提出了振兴宜宾经济的发展战略。