Sugarcane vinasse: Environmental implications of its use

The inadequate and indiscriminate disposal of sugarcane vinasse in soils and water bodies has received much attention since decades ago, due to environmental problems associated to this practice. Vinasse is the final by-product of the biomass distillation, mainly for the production of ethanol, from sugar crops (beet and sugarcane), starch crops (corn, wheat, rice, and cassava), or cellulosic material (harvesting crop residues, sugarcane bagasse, and wood). Because of the large quantities of vinasse produced, alternative treatments and uses have been developed, such as recycling of vinasse in fermentation, fertirrigation, concentration by evaporation, and yeast and energy production. This review was aimed at examining the available data on the subject as a contribution to update the information on sugarcane vinasse, from its characteristics and chemical composition to alternatives uses in Brazil: fertirrigation, concentration by evaporation, energy production; the effects on soil physical, chemical and biological properties; its influence on seed germination, its use as biostimulant and environmental contaminant. The low pH, electric conductivity, and chemical elements present in sugarcane vinasse may cause changes in the chemical and physical–chemical properties of soils, rivers, and lakes with frequent discharges over a long period of time, and also have adverse effects on agricultural soils and biota in general. Thus, new studies and green methods need to be developed aiming at sugarcane vinasse recycling and disposal.     

Fenton试剂催化氧化--混凝法处理焦化废水的实验研究

用Fenton试剂结合自制聚硅硫酸铝对焦化废水进行了催化氧化—混凝试验研究 ,选择了最佳的工作条件。结果表明 ,经氧化—混凝处理后废水的COD从 1 1 73mg/L降至 38.2mg/L ,去除率达 96 .7%。研究中还发现 ,Fenton试剂具有将废水的 pH值调节为 2 .5～ 3的特性 ,为该工艺实际处理焦化废水提供了科学依据     

苯甲酸生产废水的处理与资源化

为有效地回收甲苯液相氧化法生产苯甲酸的工业废水中的苯甲酸和乙酸,并配合废水生物降解的末端处理技术,研究了20%,30%和50%磷酸三丁酯(TBP)/煤油的混合溶剂、正辛醇和甲苯萃取苯甲酸稀溶液特性,以及对工业废水处理的实验.结果表明,TBP对苯甲酸稀溶液具有良好的萃取作用,而纯溶剂体系与溶剂的极性有关,正辛醇的萃取能力与30%TBP相当;残液中的COD_Cr值由萃取剂在水中的溶解和苯甲酸自身的COD_Cr值组成,其中残液中溶剂溶解导致的COD_Cr值随其中苯甲酸浓度变化不明显,且COD_Cr值的大小为:50%TBP≈30%TBP>正辛醇>20%TBP>甲苯.针对工业废水中主要含有苯甲酸和乙酸的工况,提出了废水资源化的处理工艺流程,即首先采用甲苯进行废水中苯甲酸的回收,之后,再利用三烷基氧磷/煤油为萃取剂回收废水中的醋酸,进一步生产绿色化学品乙酸钙镁盐.     

电池生产含铅废水处理技术研究

研究针对电池生产废水含铅、含氟、含磷、高酸性的特点,采用物化加生化的混凝气浮-化学反应-曝气生物滤池的处理工艺,去除废水中的氟、铅及部分磷酸盐,同时充分吸收、吸附污水中的污染物,达到降解有机污染物、减少污水中BOD5、COD的含量,从而达到良好的处理效果,最终达标排放。     

催化氧化法处理焦化污水生化出水的中试研究

采用ClO_2三相催化氧化工艺对焦化污水二沉池出水的处理进行了中试研究,考察了进水量、供气量、加药量等参数对焦化污水COD处理效果的影响,得出的最佳工艺条件为:进水量0.2 m~3/h,有效催化剂用量0.5 m~3,供气量10 m~3/h,盐酸投加量60 m L/h,氯酸钠投加量30 m L/h。最佳工艺条件下,平均出水COD为44 mg/L,平均去除率为80.3%,能达到国家一级排放标准。     

Denitrification potential enhancement by addition of external carbon sources in a pre-denitrification process

The aim of this study is to investigate the denitrification potential enhancement by addition of external carbon sources and to estimate the denitrification potential for the predenitrification system using nitrate utilization rate （NUR） batch tests. It is shown that the denitrification potential can be substantially increased with the addition of three external carbon sources, i.e. methanol, ethanol, and acetate, and the denitrification rates of ethanol, acetate, and methanol reached up to 9.6, 12, and 3.2 mgN/（g VSS.h）, respectively, while that of starch wastewater was only 0.74 mgN/（g VSS,h）. By comparison, ethanol was found to be the best external carbon source. NUR batch tests with starch wastewater and waste ethanol were carried out. The denitfification potential increased from 5.6 to 16.5 mg NO3-N/L owing to waste ethanol addition. By means of NUR tests, the wastewater characteristics and kinetic parameters can be estimated, which are used to determine the denitrification potential of wastewater, to calculate the denitrification potential of the plant and to predict the nitrate effluent quality, as well as provide information for developing carbon dosage control strategy.     

Treatment of 2-phenylamino-3-methyl-6-di-n-butylaminofluoran production effluent by combination of biological treatments and Fenton＇s oxidation

High strength refractory organic stream is produced during the production of 2-phenylamino-3-methyl-6-di-n-butylaminofluoran （One Dye Black 2, abbr. ODB 2）, a novel heat-sensitive material with a promising market. In this study, a combination of acidificationprecipitation, primary biological treatment, Fenton＇s oxidation and another biological treatment was successfully used for the removal of COD from 18000-25000 mg/L to below 200 mg/L from the ODB 2 production wastewater in a pilot experiment. A COD removal of 70%-80% was achieved by acidification-precipitation under a pH of 2.5-3.0. The first step biodegradafion permitted an average COD removal of 70% under an hydraulic residence time （HRT） of 30 h. By batch tests, the optimum conditions of Fenton＇s oxidation were acquired as： Fe^2＋ dose 6.0 mmol/L; H2O2 dose 3000 mg/L; and reaction time 6 h. The second step biological treatment could ensure an effluent COD below 200 mg/L under an HRT of 10 h following the Fenton＇s treatment.     

Decolorization of molasses melanoidins and palm oil mill effluent phenolic compounds by fermentative lactic acid bacteria

Lactobacillus plantarum SF5.6 is one of the lactic acid bacteria (LAB) that has the highest ability of molasses melanoidin (MM) decolorization among the 2114 strains of LAB. The strains were isolated from spoilage, pickle fruit and vegetable, soil and sludge from the wastewater treatment system by using technical step of enrichment, primary screening and secondary screening. This LAB strain SF5.6 was identified by 16S rDNA analysis and carbohydrate fermentation (API 50 CH). The top five LAB strains having high MM decolorization ( 55%), namely TBSF5.8-1, TBSF2.1-1, TBSF2.1, FF4A and SF5.6 were selected to determine the optimal condition. It was found that the temperature at 30°C under facultative conditions in GPY-MM medium (0.5% glucose, 0.1% peptone, 0.1% yeast extract, 0.1% sodium acetate, 0.05% MgSO4 and 0.005% MnCl2 in MM solution at pH 6) giving a high microbial growth and MM decolorization for all five strains. It was noticed that the decolorization of MM by LAB strains might be cell growth associated. L. plantarum SF5.6 grew rapidly within one day while the other strains took 2–3 days. This L. plantarum SF5.6 could rapidly decolorize MM to 60.91% without any lag phase, and it also had the ability to remove 34.00% phenolic compounds and 15.88% color from treated palm oil mill effluent.     

人工湿地净化海水养殖外排水影响因素与效果实验研究

以海水养殖外排水为处理对象,构建芦苇复合垂直流人工湿地模拟系统进行处理效果的影响因素(盐度,水力负荷,污染负荷)实验。植物选择芦苇,种植密度为48株/m2,基质填料选择细纱、蛭石、高炉矿渣、沸石和砾石。实验结果显示,随着盐度的升高,人工湿地对CODMn和NH4-N的去除率差异不显著(P>0.05),对PO4-P的去除率在逐渐降低,变化显著(P<0.05),但芦苇表现出较强的耐盐性,在盐度20时生长良好。随着水力负荷的增加,人工湿地对CODMn、NH4-N和PO4-P的去除率呈现出降低的趋势,变化显著(P<0.05);而当污染负荷增加时,去除率呈现出先增加后降低的趋势。综合考虑运行合理性及运行效果,得出合理工况为盐度20,水力负荷0.4 m3/(m2.d),污染负荷CODMn 10 mg/L,NH4-N 2 mg/L,PO4-P 0.5 mg/L。在此工况下,系统稳定运行2个月,显示人工湿地对海水养殖外排水中的污染物具有较好的去除效果。     

Algal toxicity induced by effluents from textile-dyeing wastewater treatment plants

This research aimed to evaluate the alga Scenedesmus obliquus toxicity induced by textiledyeing effluents(TDE).The toxicity indicator of TDE in alga at the physiological(algal growyth),biochemical(chlorophyll-a(Chl-a) synthesis and superoxide dismutase(SOD) activity) and structural(cell membrane integrity) level were investigated.Then we further study the relationship among toxicity indicators at physiological and biochemical level,and supplemented by research on algal biomacromolecules.Accordin...