化工废水生态毒性原因鉴别的实例研究

以南京市某一化工厂排出的废水为对象,对其生态毒性原因作了鉴别研究．结果表明,废水对Ｄａｐｈｎｉａｍａｇｎａ具有急性毒性,Ｃ１８固相提取可去除废水毒性,存在的主要毒物为非极性有机化合物．废水经Ｃ１８固相提取,发现废水中的主要可疑毒物为苯并吡喃酮和苯酚,是导致废水毒性的关键污染物,对废水毒性的贡献率分别为４４．６％和３２．９％．     

光合细菌与酵母菌综合处理柠檬酸废水的初步研究

对应用光合细菌和酵母菌综合处理柠檬酸废水进行了初步研究,考察了各段工艺的处理效果。结果表明,第一步用热带假丝酵母处理后,CODCr去除率为13．6％,出水pH为7．5,沉淀的酵母泥干重得率7．0g／L,蛋白质含量47％;第二步用光合细菌处理后,CODCr去除率为58％,总去除率达63．7％,出水pH为9．6,絮凝沉淀的光合菌泥干重得率1．2g／L,蛋白质含量51％。     

Enhanced solid–liquid separation of dairy manure with natural flocculants

The aim of this study was to determine the effectiveness of natural flocculants to reduce solids and nutrient loads in dairy cow wastewater using solid–liquid separation; chitosan was used as a model. Its use efficiency and optimum application rate were determined using flushed dairy cow manure of varied strengths – 0.4%, 0.8%, 1.6%, and 3.2% total solids (TS) content. Treatments consisted of nine rates of chitosan. The flocculated manure was dewatered using 1-mm and 0.25-mm screens. Separation by screening alone was not effective; average efficiencies were about 60% for total suspended solids (TSS), 22% for total Kjeldahl nitrogen (TKN), and 26% for total phosphorus (TP). Mixing with chitosan before screening substantially increased separation. At optimum chitosan rate (0.5 g/L for the highest strength effluent), separation efficiencies were >95% for TSS, >73% for TKN, and >54% for TP. The results of this study indicate that natural flocculants such as chitosan are useful for the solid–liquid separation treatment of livestock wastewater.     

Solid-state C NMR to assess organic matter transformation in a subsurface wetland under cheese-dairy farm effluents

Solid-state ¹³C NMR were used to follow organic matter transformation in a subsurface wetland under the effluent of a small cheese-dairy farm under a Mediterranean climate. The results showed that the ratios commonly used to quantify humification, (aromaticity and Alkyl-C/O-Alkyl-C ratios) can be considered as relevant chemical indicators of organic matter transformation. Polysaccharides were transformed throughout the subsurface wetland whereas aromatic, phenolic and alkyl compounds accumulated. Furthermore, Phenolic-C signal and O-Alkyl-C signal were negatively correlated to proteases and β-galactosidase activities showing that recalcitrant molecules actually accumulated. These results were correlated with high purification yields: the average decrease in chemical demand in oxygen was 90.75% and that in Total Kjeldahl Nitrogen was 75.65%. Thus subsurface wetlands can be considered as an efficient technology to purify effluents with high organic matter contents, such as cheese-dairy effluent, under drastic climate conditions. Furthermore this study highlights the fact that solid-state ¹³C NMR is a suitable tool to follow organic matter transformation.     

Investigation of soluble microbial products in a full-scale UASB reactor running at low organic loading rate

Investigation on a full-scale UASB treating industrial wastewater at a low organic loading rate (OLR) was conducted. Excellent treatment performance was achieved when treating the evaporator condensate of distillery wastewater at the OLR of less than 1 kg COD/m³ d. Anaerobic effluent could be discharged without further treatment, which saved energy and running cost considerably. GC–MS analysis showed that the soluble microbial products (SMPs) were decreased to a low level at the low OLR. The main SMP in the anaerobic effluent were long chain carbohydrates and esters, accounting for 55–65% of the total organic matters. Anaerobic SMP was more complex than the aerobic ones.     

Accumulation of Metals and Boron in Phragmites australis Planted in Constructed Wetlands Polishing Real Electroplating Wastewater

The concentration of metals (Al, Cu, Fe, Mn, Ni, Zn) and B were determined in the above- and belowground biomass of Phragmites australis collected from the microcosm constructed wetland system used for the polishing of real electroplating wastewater. Translocation factor and bioconcentration factor were determined. Pearson correlation test was used to determine correlation between metal concentration in substrate and above- and belowground parts of Phragmites australis. The obtained results suggested that Phragmites australis did not play a major role as an accumulator of metals. It was observed also that the substrate could have exerted an effect on the translocation of Ni, Cu, Zn and Mn. The analysed concentrations of metals and B in biomass were in the range or even below the concentrations reported in the literature with the exception of Ni. The aboveground biomass was found suitable as a composting input in terms of metals concentrations.     

Phytoaccumulation of Heavy Metals in Natural Plants Thriving on Wastewater Effluent at Hattar Industrial Estate,Pakistan

The objective of this research was to compare the potential of native plants for the phytoaccumulation of heavy metals (HM). Thirteen predominant plant species (including trees, bushes and grasses) namely Ricinus communis, Ipomoea carnea, Cannabis sativa, Parthenium hysterophorus, Acacia nilotica, Dalbergia sissoo, Acacia modesta, Solanum nigrum, Xanthium stromarium, Chenopodium album, Cynodon dactylon, Eleusine indica, and Dactyloctenium aegyptium were collected from the wastewater originated from Hattar industrial estate of Pakistan, Plants shoots and roots were analyzed for heavy metals / metalloid: Pb, Cr, Cd, Zn, Fe, Ni, and As. Among plant species, the accumulation potential for HM varied depending on the type of element. Regardless of the plant species, HM concentrations varied in the order of Fe > Zn > Cr > Pb > Ni > Cd > As. Tree species of R. communis, A. nilotica, A. modesta, and D. sissoo exhibited an enhanced concentrations of metals. Accumulation pattern of Fe, Pb, Cd, and As in plants could be related to the HM composition of soil and wastewater. Most of the species exhibited higher HM composition in the root as compared to shoot. The species that found with greater ability to absorb HM in the root, got higher HM concentrations in its shoot. Shoot tissue concentrations of HM were attained by the species as D. sissoo > A. modesta > A. nilotica > R. communis > I. carnea > C. album > E. indica > P. hysterophorus > S. nigrum > C. sativa > D. aegyptium > X. strumarium > C. dactylon. Based on results, tree plants were noticed as higher accumulators of HM in polluted soils.     

脱氮菌株P6的分离鉴定及其处理氨氮废水的试验研究

目的：从污水处理池的污泥中分离得到去除氨氮效果较好的菌株,对其进行分类鉴定和去除氨氮的最佳条件的研究。方法：根据维诺格拉斯基柱法分离出几种纯菌株,选取其中脱氮效果较好的一株,经形态观察和生理生化实验,鉴定其分类地位。研究不同培养条件对该菌生长的影响,用滴定法测定不同条件下其对氨氮的去除率。结果：获得一脱氮菌株P6,初步推测该菌为产碱杆菌。其最适生长条件为：温度29℃,初始pH值7.5以及摇床（100r/min）培养,且在温度29℃、废水的初始pH值11、接种量与废水体积的比例为1.2g/150mL、添加乙酸钠浓度为0.1%、废水的氨氮浓度为600mg/L和摇床（100r/min）的条件下,3d后该菌对氨氮的去除率达到45%。结论：P6菌有一定的去除氨氮能力,具有应用价值。     

Two-stage biological treatment of olive mill wastewater with whey as co-substrate

Olive mill wastewater (OMW) is a highly polluting wastewater, caused by a high organic load and phenol content. These characteristics suggest that it may be suitable for aerobic treatment and anaerobic bacterial digestion. Aerobic treatment coupled with anaerobic bacterial digestion may be economically feasible as the methane produced is a valuable energy source while simultaneously purifying the OMW. In an attempt to improve the overall performance of the process, the addition of a co-substrate such as whey to the aerobic treatment pre-treatment of OMW by the yeast Candida tropicalis was studied.The two-stage system operated satisfactorily up to an organic loading rate (OLR) of 3.0 kg COD L⁻¹ day⁻¹ with a biogas production rate of 1.25 L_biogas L_reactor⁻¹ day⁻¹ and a total COD reduction in excess of 93% (62% COD reduction in aerobic pretreatment and 83% COD reduction in anaerobic digestion). Fifty-four percent of the phenol was biodegraded during the aerobic treatment stage, and biogas with between 68% and 75% methane was produced during anaerobic digestion.     

Biosorption of Lead from Industrial Wastewater Using Chrysophyllum albidum Seed Shell

The shell of the seed of Chrysophyllum albidum carbon was used to adsorb lead (Pb) from aqueous solution, the sorption process with respect to its equilibria and kinetics as well as the effects of pH, contact time, adsorbent mass, adsorbate concentration, and particle size on adsorption were also studied. The most effective pH range was found to be between 4.5 and 5 for the sorption of the metal ion. The first-order rate equation by Lagergren was tested on the kinetic data and the adsorption process followed first-order rate kinetics. Isotherm data were analyzed for possible agreement with the Langmuir and Freundlich adsorption isotherms; the Freundlich and Langmuir models for dynamics of metal ion uptake proposed in this work fitted the experimental data reasonably well. However, equilibrium sorption data were better represented by Langmuir model than Freundlich. The adsorption capacity calculated from Langmuir isotherm was 72.1 mg Pb (II) g^{- 1} at initial pH of 5.0 at 30°C for the particle size of 1.00 to 1.25 mm with the use of 2.0 g/100 ml adsorbent mass. The structural features of the adsorbent were characterized by Fourier transform infrared (FTIR) spectrometry; the presence of hydroxyl, carbonyl, amide, and phosphate groups confirms the potential mechanism adsorption of the adsorbent. This readily available adsorbent is efficient in the uptake of Pb (II) ion in aqueous solution, thus, it could be an excellent alternative for the removal of heavy metals and organic matter from water and wastewater.