The effect of paper industry effluent on growth, pigments, carbohydrates and proteins of rice seedlings

The effect of paper industry effluent on the growth and content of certain macromolecules of seedlings of rice (Oryza sativa L. cv. Kesari-82K) has been examined. The effects were investigated in relation to both concentration of effluent and time of exposure to the effluent. Percentage of germination, water imbibing capacity, growth, pigment, carbohydrate and protein content showed a decreasing trend with increase in effluent concentration and time. Protein content was the most sensitive macromolecule affected by effluent. Measurement of protein and protein enzymes might therefore provide a useful criterion for the evaluation of the phytotoxicity of effluent released from the pulp and paper industries.     

The effectiveness of lime-based amendments and bauxite residues at removing phosphorus from piggery effluent

Piggery effluent may contribute to the eutrophication of waterways, if it is not treated before disposal, because of high levels of phosphorus. Limes and red muds (a residue from bauxite refining) were used to remove phosphorus from piggery effluent (41 mg litre(-1) total P). Lime-based amendments were more effective than the red muds at removing phosphorus when compared at the same liquid: solid ratios. Based on laboratory data, the cost of treating effluent increased rapidly as the final required phosphorus concentration decreased to less than 4 mg litre(-1). Kiln dust was the cheapest amendment tested down to 2 mg litre(-1). Hydrated lime was able to clarify and flocculate the effluent to 1 mg litre(-1) within 60 min. The re-useability of all limes may be determined by a simple pH test. Red mud could be used to remove phosphorus when its pH was lowered to 6.0-6.5 and it is used at liquid:solid ratios <20:1.     

Transformation of molecular weight distributions of dissolved organic carbon and UV-absorbing compounds at full-scale wastewater-treatment plants.

The molecular-weight distribution (MWD) of wastewater dissolved-organic carbon (DOC) was determined in samples from seven full-scale wastewater-treatment plants (WWTPs) that use different biological treatments (air activated sludge [air-AS], pure-oxygen AS [O2-AS], and trickling filters). The research objective was to determine how different biological treatments influenced the MWD of wastewater DOC. Primary sedimentation effluent DOC from most of the WWTPs exhibited a skewed distribution toward the low-molecular-weight fraction (MWF) (40 to 50%, < 0.5 K Daltons [KDa]). The Air-AS effluent DOC exhibited a centrally clustered distribution, with the majority of DOC in the intermediate MWF (0.5 to 3 KDa). The O2-AS effluent DOC exhibited a skewed distribution toward the high MWF (> 3 KDa). The removal of DOC by air- and O2-AS bacteria followed trends predicted by a macromolecule degradation model. Trickling-filter effluent DOC exhibited a skewed distribution toward the high MWF (50% DOC, > 3 KDa).     

Evaluation of the operating performance of conventional versus flocculator secondary clarifiers at the Kuwahee Wastewater Treatment Plant, Knoxville, Tennessee.

The difference in performance of three differently designed circular secondary clarifiers in the same wastewater treatment plant was analyzed in this paper. Data obtained using flocculated suspended solids and disperse suspended solids tests were analyzed using statistical tools. The conventional clarifier showed more variability in the average effluent suspended solids concentration when compared with the flocculator-clarifiers. Furthermore, a difference in performance among the two different flocculator-clarifiers was found.     

The distribution of polychlorinated dibenzo-p-dioxins and dibenzofurans in Jackfish Bay, Lake Superior, in relation to a kraft pulp mill effluent

Samples of whole effluent and effluent suspended solids from a kraft pulp mill and sediments and biota from Jackfish Bay, Lake Superior were analyzed for polychlorinated dibenzo-p-dioxins (CDDs) and dibenzofurans (CDFs). Tetra-CDFs (4CDF) were consistently detected in whole effluent at levels ranging between 0.3 and 1.3 ng/L. Effluent suspended solids also contained 4CDFs as well as traces of 4CDD, 5CDF, 8CDF and 8CDD. The horizontal sediment distribution suggests that the effluent was the only active source of 4CDF in the area but that 8CDD originated from a more general source such as the atmosphere. An abrupt appearance of 4CDF in the more recent sections of a core profile taken in the bay suggests that an operational change at the pulp mill resulted in the formation of 4CDFs in the mill effluent some time after 1973. Moderate values of 4CDF and low values of 4CDD were found in samples of the shrimp confirming the presence of an active source of 4CDF in Jackfish Bay.     

Semiconductor-assisted photodegradation of lignin, dye, and kraft effluent by Ag-doped ZnO

This work reports a preliminary study of semiconductor-assisted photochemical degradation of lignin, Remazol Brilliant Blue R and Kraft E1 paper effluent by using ZnO and Ag-doped ZnO photocatalysts. The doped semiconductor was prepared in the reaction media by photoreduction of silver nitrate. With the use of 100 mg of ZnO and 15 mg of Ag-ZnO, almost total decolorization of the dye and lignin samples in reaction times lower than 60 min were observed. Extending the photochemical reaction up to 120 min, the total organic carbon content (TOC) was reduced in 90%. For the paper effluent, a fast decolorization was obtained for relatively short reaction times. However, de TOC reduction was negligible (near of 10%) up to high reaction times (300 min). By using the Ag-ZnO photocatalyst, the toxicity of lignin and Kraft E1 effluent toward E. Coli was completely removed. For the dye, the formation of transient toxic species was observed.     

污水土壤含水层处理系统原理、管理、效率和应用

论述了污水土壤含水层处理系统中的地球化学过程.该系统通过对污染物的机械过滤、生物化学转化和降解过程、吸附/解吸过程、氧化/还原过程、沉淀/溶解过程、以及矿物的合成过程净化污水.运作周期通常为1～2 d灌水/4～5 d排干,年水力负荷变化于15～100 m之间,应根据季节变化调整水力负荷.该系统能有效去除污水中的微生物和悬浮物,降低COD和BOD含量,和去除潜在的有毒的无机成分,如重金属和含氧阴离子.作为一种低投资、低能耗、高净化效率、运行简单的自然的污水处理技术,其在世界各国得到了广泛应用.我国部分地区水资源极其短缺,在土壤和气候条件适合的地区,应用土壤含水层处理技术处理污水,实现污水资源化,既解决了污水污染环境问题,又将在一定程度上缓解该地区的水资源短缺问题,对于经济与环境的协调发展具有重要意义.     

A novel thermotolerant Pediococcus acidilactici B-25 strain for color, COD, and BOD reduction of distillery effluent for end use applications

The present study was aimed to characterize physico-chemical and microbial population of distillery effluent and isolate a novel thermotolerant bacterium for color, COD, and BOD reduction of spentwash. The level of alkalinity, TSS, DO, COD, BOD, TN, ammonical nitrogen, nitrate nitrogen, phosphorous, potassium, chloride, and calcium of spentwash (SW), bioreactor effluent (BE), and secondary treated effluent (STE) were well above the permissible limits. The level of color, TS, and TDS were under the permissible limits for STE but not for SW and BE. The microbial population was higher in BE. The results revealed that effluent was highly polluted and require suitable treatment before discharge. A novel thermotolerant bacterium, identified as Pediococcus acidilactici, was isolated which exhibited maximum 79 % decolorization, 85 % COD, and 94 % BOD reduction at 45 °C using 0.1 %, glucose; 0.1 %, peptone; 0.05 %, MgSO4; 0.05 %, K₂HPO₄; pH 6.0 within 24 h under static condition. The ability of this strain to decolorize melanoidin at minimum carbon and nitrogen supplementation warrants its possible application for effluent treatment at industrial level. In addition, it is first instance when melanoidin decolorization was reported by P. acidilactici. This study could be an approach towards control of environmental pollution and health hazards of people in and around the effluent distillery unit.     

啤酒废水常温厌氧消化启动及运行实验

采用自行设计的复合式厌氧反应器在常温下对啤酒废水进行了厌氧发酵产沼气的实验研究,将进水COD控制在5 000 mg/L左右,采取逐步缩短HRT的方法来提高进水有机负荷,结果表明,启动运行41 d之后,产气量上升速度加快,反应器成功启动运行;在稳定运行过程中,随着负荷的升高,产气量呈阶梯式渐次上升,COD去除率保持在90%以上,出水pH值维持在7.0左右,TSS去除率达到60%以上,出水水质较好,说明该反应器具有较好的厌氧消化处理有机废水的能力。     

Dechlorination of chloroorganics,decolorization, and simultaneous bioremediation of Cr6+ from real tannery effluent employing indigenous Bacillus cereus isolate

A native Bacillus cereus isolate has been employed, for the first time, for simultaneous decolorization, dechlorination of chloroorganics, and Cr⁶⁺ remediation from the real tannery effluent. Most of the physicochemical variables in 3:1 diluted effluent were well above the standard prescribed limits, which decreased substantially upon microbial treatment. The extent of bioremediation was better in diluted (3:1) as compared to undiluted effluent supplemented with nutrients and augmented with B. cereus isolate. Maximum growth, effluent decolorization (42.5 %), dechlorination (74.1 %), and Cr⁶⁺ remediation (34.2 %) were attained with 4.0 % (v/v) inoculum, 0.8 % glucose, and 0.2 % ammonium chloride in 3:1 diluted effluent at natural pH (8.1) within 72 h of incubation. The efficiency of bioremediation in a bioreactor was higher as compared to a flask trial during 72 h of incubation: decolorization (47.9 %) was enhanced by 5.4 %, dechlorination (77.4 %) by 3.3 %, and Cr⁶⁺ removal (41.7 %) by 7.5 % at an initial color of 286 Pt-Co units and initial concentration of 62 mg chloride ions and 108 mg l^?1 Cr⁶⁺. Immobilized biomass of Pseudomonas putida and B. cereus coculture enhanced the extent of Cr⁶⁺ remediation (51.9 %) by 10.2 % compared to the bioreactor trial. Chromate reductase activity and reduced Cr directly correlated and were mainly associated with soluble fraction of B. cereus plus effluent natural microflora. The GC-MS analyses revealed the formation of metabolites such as acetic acid and 2-butenoic acid in bacterially treated effluent. The supplementation of nutrients along with B. cereus augmentation is required for efficient effluent bioremediation.     

矿物载体锯末碳源低温生物修复硝酸盐污染地下水

研究了低温条件下,沸石和火山岩为载体,锯末为碳源的生物反应器对地下水中硝酸盐氮的去除效果。结果表明,在（14±1）℃,水力停留时间18 h,进水硝酸盐氮浓度为27 mg/L的条件下,以锯末为碳源能有效去除地下水中的硝酸盐,沸石为载体时对硝酸盐氮的平均去除率为98%;火山岩为载体时对硝酸盐氮的平均去除率为95%。实验过程中出现铵盐和亚硝酸盐的积累,出水中氨氮浓度为1～2.55 mg/L,亚硝酸氮浓度为0～0.98 mg/L。出水pH均介于7～8,满足饮用水标准中pH的要求（6.5～8.5）。     

Characterization of preferential flow in undisturbed, structured soil columns using a vertical TDR probe

Rapid movement of agricultural chemicals through soil to groundwater via preferential flow pathways is one cause of water contamination. Previous studies have shown that time domain reflectometry (TDR) could be used to characterize solute transport in soil. However, previous studies have only scarcely addressed preferential flow. This study presents an extended application of TDR for determining preferential flow properties. A TDR method was tested in carefully controlled laboratory experiments using 20-cm long and 12-cm diameter undisturbed, structured soil columns. The method used a vertically installed TDR probe and a short pulse of tracer application to obtain residual mass (RM) breakthrough curves (BTC). The RM BTC obtained from TDR were used to estimate mobile/immobile model (MIM) parameters that were compared to the parameter estimates from effluent data. A conventional inverse curve fitting method (CXTFIT) was used to estimate parameters. The TDR-determined parameters were then used to generate calculated effluent BTC for comparison with observed effluent BTC for the same soil columns. Time moments of the calculated and observed BTC were calculated to quantitatively evaluate the calculated BTC. Overall, the RM BTC obtained from TDR were similar to the RM BTC obtained from effluent data. The TDR-determined parameters corresponded well to the parameters obtained from the effluent data, although they were not within the 95% confidence intervals. Correlation coefficients between the parameters obtained from TDR and from effluent data for the immobile water fraction (theta im/theta), mass exchange coefficient (alpha), and dispersion coefficient (Dm) were 0.95, 0.95, and 0.99, respectively. For three of the four soil cores, theta im/theta ranged from 0.42 to 0.82, indicating considerable preferential flow. The TDR-calculated effluent BTC also were similar to the observed effluent BTC having an average coefficient of determination of 0.94. Time moments obtained from calculated BTC were representative of those obtained from observed BTC. The vertical TDR probe method was simple and minimally destructive and provided representative preferential flow properties that enabled the characterization of solute transport in soil.     

Copper-promoted heterogeneous Fenton-like oxidation of Rhodamine B over Fe3O4 magnetic nanocatalysts at mild conditions

Environmental Science and Pollution Research - Rhodamine B (RhB) is used in various industries and its effluent must be effectively treated because of its harmful and carcinogenic nature. In this...     

A comparative study of photo-Fenton process assisted by natural sunlight,UV-A,or visible LED light irradiation for degradation of real textile wastewater: factorial designs,kinetics, cost assessment,and phytotoxicity studies

Environmental Science and Pollution Research - The present work aims to evaluate the treatment of the effluent from the textile industry via advanced oxidative processes of photo-Fenton assisted by...     

Toxicity to Microtox, micro-algae and duckweed of effluents from the Bai Bang paper company (BAPACO), a Vietnamese bleached kraft pulp and paper mill

Toxicity of the combined effluent as well as effluents from different production units of BAPACO, a Vietnamese bleached kraft integrated pulp and paper mill, was studied using three ecotoxicological tests: Microtox, the micro-alga, Selenastrum capricornutum, and the duckweed, Lemna aequinoctialis. Physico-chemical characteristics of the effluents were also analyzed. Due to unstable operating conditions of the mill, a number of samples taken at different monitoring periods from each effluent were tested, in order to get statistically reliable ranges and averages of toxicity characteristics. For the mill combined effluent, it was found that the micro-algae were the most sensitive followed by Microtox bacteria, while duckweed was not sensitive. Microtox tests showed that the bleaching filtrate from the chlorination stage (C-stage) was the most toxic among all effluents in the mill. The combined effluent from the bleaching plant contributed the largest TEF (Toxicity Emission Factor) to the toxicity balance of the whole BAPACO combined effluent. A less-than-additive mode of toxicity was obtained. In spite of high pollution loads, e.g. BOD, COD, SS, to the Red River, the toxicity of the effluent was considered to be low. However, during periods of low river water sublethal toxic effects on the biota may be expected.     

Treatment of pretreated coking wastewater by flocculation,alkali out,air stripping,and three-dimensional electrocatalytic oxidation with parallel plate electrodes

The coking wastewater generally comprises highly concentrated, recalcitrant, and toxic organic pollutants, so its treatment has been of great importance to prevent living beings and their environment from these hazardous contaminations. The treatment of pretreated coking wastewater by flocculation-coagulation, alkali out, air stripping, and three-dimensional (3-D) electrocatalytic oxidation was performed (gap between the used β-PbO₂/Ti anode and titanium cathode, 12 mm; mass ratio of Cu-Mn/granular activated carbon (GAC) to effluent, 1:4; cell voltage, 7 V). The results showed that the pH adjusting from 3.7 to 6.1 was necessary for coagulants; alkali out played an important role because it brought up precipitation containing higher fatty acids as well as other contaminants to decrease the chemical oxygen demand (COD) in the effluent, and it had also forced the reduction of ammonia nitrogen (NH₃-N) by incorporating with air stripping; for 3-D electrocatalytic oxidation with a bleaching liquid assisting, the initial pH 8.5 of effluent was suitable for Cu-Mn/GAC; moreover, it was considered that its Cu component was dedicated to the decrease of COD and NH₃-N, while the Mn component specialized in the decay of NH₃-N. The residual COD and NH₃-N values in the final effluent with pH 6.5 were 95.8 and 8.8 mg/L, respectively, demonstrating that the whole processes applied were feasible and low in cost.     

Numerical analysis of an 80,000 Nm3/h fly ash entrained-flow gasifier at various burner inclination angles

Environmental Science and Pollution Research - The raw syngas effluent from a fluidized bed gasifier typically contains a large amount of fly ash having a high concentration of carbon, which is...     

低温下ZCS工艺和改进式ZCS工艺脱氮效率研究及微生物特性分析

考察冬季低温下沸石联合生物吸附再生工艺和改进式沸石联合生物吸附再生工艺对城市污水的脱氮效率,结果表明在HRT为3.5 h下,ZCS工艺出水氨氮为11.65 mg/L,总氮高于20 mg/L.而相同条件下MZCS工艺氨氮出水为5.45 mg/L,总氮去除率比原ZCS工艺提高了11%,均值为16.8 mg/L.通过聚合酶链式技术,变性梯度凝胶电泳和电镜扫描技术发现两工艺微生物多样性、丰度高于传统活性污泥法,兼具活性污泥法和生物膜法的微生物特性.     

Process performance evaluation of the contact stabilisation system at Birzeit University

The purification capacity of the contact stabilisation system at Birzeit University campus has been studied for two years. The oxidation capacity of organic matter, ammonium oxidation, and denitrification potential were determined. The reduction of chemical oxygen demand (COD) was 85%, and the effluent COD concentration was less than 110 mg/l (the average value was 88 mg/l). Suspended solids were removed with equal efficiency. The aerobic stabilization of organic solids was efficient, and no excess biosolids (sludge) had to be removed. High nitrification (70% of the influent nitrogen were nitrified) could be maintained at 15°C, and 42% of the oxidised nitrogen was denitrified. The specific oxygenation capacity of the treatment system is relatively high and reached about 5 kwh/kg COD. The specific wastewater treatment cost is about 0.52 US$/m3 or about 58 US$ per population equivalent per year. Based on the results obtained, batch operation and intermittent aeration of the biological process are suggested to achieve high effluent quality and to reduce power consumption.     

Occurrence and abundance of tetracycline,sulfonamide resistance genes,and class 1 integron in five wastewater treatment plants

To understand the transport and fate of antibiotic resistance genes in wastewater treatment plants, 12 resistance genes (ten tetracycline resistance genes, two sulfonamides genes) and class 1 integron gene (intI1) were studied in five wastewater treatment plants with different treatment processes and different sewage sources. Among these resistance genes, sulfonamides genes (sul1 and sul2) were of the most prevalent genes with detection frequency of 100 %. The effluent water contained fewer types of resistance genes than the influent in most selected plants. The abundance of five quantified resistance genes (tetG, tetW, tetX, sul1, and intI1) decreased in effluent of plants treating domestic or industrial wastewater with anaerobic/aerobic or membrane bioreactor (MBR) technologies, but tetG, tetX, sul1, and intI1 increased along the treatment units of plants treating vitamin C production wastewater by anaerobic/aerobic technology. In plant treating cephalosporins production wastewater by UASB/aerobic process, the quantities of tetG, tetX, and sul1 first decreased in anaerobic effluent water but then increased in aerobic effluent water.