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351.
响应面分析法优化造纸污泥吸附剂除磷工艺 总被引:2,自引:0,他引:2
以造纸厂废水污泥为原料,采用微波加热法制备造纸污泥吸附剂。利用制备的造纸污泥吸附剂对模拟含磷废水进行了吸附研究,探讨了吸附时间、投加量、pH值、转速和温度等因素对除磷效果的影响,并采用响应面设计法优化吸附工艺条件。结果表明,获得了最佳除磷工艺条件为吸附时间97 min,投加量6.9 g/L,pH=6,转速200 r/min,温度30℃,在此条件下磷的去除率可达99%以上。因此,造纸污泥吸附剂对磷的吸附效果良好,具有重要的实际应用价值。 相似文献
352.
造纸中段废水与生活污水合并深度处理工艺 总被引:2,自引:0,他引:2
采用水解酸化+CAST+混凝+复合滤池与水解酸化+接触氧化+混凝+复合滤池2种组合工艺对造纸中段废水与生活污水进行合并处理对照试验.结果表明,两种工艺都是切实可行的,二级出水均可达到《污水综合排放标准》(GB8978-1996)二级标准,深度处理出水可达中水水质要求.其中以水解酸化+CAST+混凝+复合滤池组合工艺效果最好. 相似文献
353.
废纸脱墨废水混凝性能研究 总被引:4,自引:0,他引:4
对脱墨废水混凝处理的混凝剂和助凝剂的种类和用量进行了试验.结果表明:PIO较硫酸铝混凝性能好,添加少量PAM助凝剂有利于絮凝物的沉降,脱墨废水中SS、CODCr和BOD5的去除率分别达到85.4%,78.2%和71.7%. 相似文献
354.
355.
356.
A bench-scale expanded granular sludge bed (EGSB) reactor was applied to the treatment of palm oil mill ettluent (POME).The reactor had been operated continuously at 35℃ for 514 d,with organic loading rate (OLR) increased from 1.45 to 17.5 kg COD/(m3·d).The results showed that the EGSB reactor had good performance in terms of COD removal on the one hand,high COD removal of 91% Was obtained at two days’ of hydraulic retention time (HRT),and the highest OLR of 17.5 kg COD/(m3·d).On the other hand,only 46% COD in raw POME Was transformed into biogas in which the methane content was about 70% (v/v).A 30-d intermittent experiment indicated that the maximum transformation potential of organic matter in raw POME into methane Was 56%.Volatile fatty acid (VFA) accumulation was observed in the later operation stage,and this Was settled by supplementing trace metal elements.On the whole,the system exhibited good stability in terms of acidity and alkalinity.Finally, the operational problems inherent in the laboratory scale experiment and the corresponding countermeasures were also discussed. 相似文献
357.
Background, aim, and scope The pulp and paper industry is the sixth largest polluter discharging a variety of gaseous, liquid, and solid wastes into
the environment. Effluents from bleached Kraft mill effluents (BKME) are polluting waters to a great extent These effluents
cause considerable damage to the receiving waters if discharged untreated since they have high levels of biological oxygen
demand (BOD), chemical oxygen demand (COD), chlorinated compounds (measured as AOX), suspended solids (mainly fibers), fatty
acids, tannins, resin acids, lignin and its derivatives, sulfur and sulfur compounds, etc. This study aimed to remove adsorbed
organic halogen (AOX), total nitrogen, and lignin-degrading products in the wastewater (4,500 m3/h) from the paper mill in the pulp and paper industry, which is discharged to sea from a plant located in western Turkey.
Materials and methods The photocatalytic degradation of AOX, total nitrogen, and chlorinated lignin in BKME have been investigated in different
parameters, such as time, H2O2 and TiO2 concentration. In addition, for investigating the effect of chlorine on the removal of lignin, pure lignin solution was prepared
in equal amounts to chlorinated lignin degradation products found in BKME. The same experiments were conducted for this solution.
Experiments were carried out in photocatalytic reactor made of Pyrex glass. The mercury lamp was used as a radiation source.
All irradiation was carried out under constant stirring. The existence of dissolved O2 is an important factor which increases the photocatalytic degradation. Hence, we used an air pump for the aeration of the
wastewater solutions. The temperature of the wastewater was controlled and adjusted to 25°C by thermostat pump in conjunction
with a cooler. At the end of all experiments, AOX, total nitrogen and lignin concentrations were analyzed according to standard
methods. All experiments were performed in duplicate and average values were used.
Results and discussion When the effect of H2O2 and time were investigated, it was observed that the AOX concentration increased from 3.0 to 11.0 mg/L by only UV. However,
when H2O2 was added, AOX concentration decreased from approximately 3.0 to 0.0 mg/L. The optimal conditions for the removal of AOX
appear to be an initial H2O2 concentration of 20.0 mL/L and reaction time of 50 min. In addition, at the same experiment conditions, it was seen that
the total nitrogen concentration decreased from 23.0 to 15.0 mg/L by only UV and by increasing H2O2 concentration, the concentration of 20.0 mL/L H2O2 appears to be optimal (9.0 mg/L). The AOX, total nitrogen and lignin degradation products and pure lignin go through a minimum
when the concentration of H2O2 and TiO2 increases at constant pH and UV intensity. The kinetics for the degradation of AOX, total nitrogen and lignin degradation
products followed a pseudo-first order law with respect to the products, and the degradation rates (min−1) for the UV/TiO2/H2O2 system were higher than that of the corresponding values for the UV/H2O2 system.
Conclusions The AOX, total nitrogen and lignin concentration go through a minimum when the concentration of H2O2 and TiO2 increases at constant pH and UV intensity. It was found that the UV/TiO2/H2O2 system has proved capable of the degradation of total nitrogen as well as chlorinated and degraded lignin in BKME.
Recommendations and perspectives The photocatalytic process can be considered a suitable alternative for the remove of some compounds from the BKME. Nevertheless,
further studies should be carried out to confirm the practical feasibility of BKME. Another result obtained from the study
is that pre-purification carried out with UV/TiO2/H2O2 photocatalytic process may constitute an important step for further purification processes such as adsorption, membrane processes,
etc. 相似文献
358.
359.
Disposal of untreated olive mill waste waters (OMW) is a serious environmental problem in many Mediterranean countries. The aim of this work was to assess whether changes in soil properties have occurred due to direct disposal of raw OMW on soil and in evaporation ponds, and to investigate the potential fate and transport of pollutants after olive oil production had ceased. The results clearly showed that uncontrolled OMW disposal is a significant source of pollution to surface soil and waters. Disposal of OMW on soil greatly increased electrical conductivity (EC), available phosphorous (P), exchangeable potassium (K) and magnesium (Mg), organic matter, polyphenols, total and inorganic nitrogen (N), and available micronutrients mainly in surface soil layers. The presence of a high content of clay and carbonates in soil act as barriers and prevent downward transport of pollutants. Residual levels of total carbon (C), polyphenols, total and inorganic N, exchangeable K+, available P, iron (Fe), and copper (Cu) were also elevated even 8 years after mill closure. The long term disposal of OMW highlights the need to establish soil quality standards for soil parameters in order to identify soils affected by the disposal of OMW. 相似文献
360.
Volatile organic compounds (VOCs) are regulated aerial pollutants that have environmental and health concerns. Swine operations produce and emit a complex mixture of VOCs with a wide range of molecular weights and a variety of physicochemical properties. Significant progress has been made in this area since the first experiment on VOCs at a swine facility in the early 1960s. A total of 47 research institutions in 15 North American, European, and Asian countries contributed to an increasing number of scientific publications. Nearly half of the research papers were published by U.S. institutions.Investigated major VOC sources included air inside swine barns, in headspaces of manure storages and composts, in open atmosphere above swine wastewater, and surrounding swine farms. They also included liquid swine manure and wastewater, and dusts inside and outside swine barns. Most of the sample analyses have been focusing on identification of VOC compounds and their relationship with odors. More than 500 VOCs have been identified. About 60% and 10% of the studies contributed to the quantification of VOC concentrations and emissions, respectively. The largest numbers of VOC compounds with reported concentrations in a single experimental study were 82 in air, 36 in manure, and 34 in dust samples.The relatively abundant VOC compounds that were quantified in at least two independent studies included acetic acid, butanoic acid (butyric acid), dimethyl disulfide, dimethyl sulfide, iso-valeric, p-cresol, propionic acid, skatole, trimethyl amine, and valeric acid in air. They included acetic acid, p-cresol, iso-butyric acid, butyric acid, indole, phenol, propionic acid, iso-valeric acid, and skatole in manure. In dust samples, they were acetic acid, propionic acid, butyric acid, valeric acid, p-cresol, hexanal, and decanal. Swine facility VOCs were preferentially bound to smaller-size dusts.Identification and quantification of VOCs were restricted by using instruments based on gas Chromatography (GC) and liquid chromatography (LC) with different detectors most of which require time-consuming procedures to obtain results. Various methodologies and technologies in sampling, sample preparation, and sample analysis have been used. Only four publications reported using GC based analyzers and PTR-MS (proton-transfer-reaction mass spectrometry) that allowed continuous VOC measurement. Because of this, the majority of experimental studies were only performed on limited numbers of air, manure, or dust samples. Many aerial VOCs had concentrations that were too low to be identified by the GC peaks.Although VOCs emitted from swine facilities have environmental concerns, only a few studies investigated VOC emission rates, which ranged from 3.0 to 176.5 mg d−1 kg−1 pig at swine finishing barns and from 2.3 to 45.2 g d−1 m−2 at manure storages. Similar to the other pollutants, spatial and temporal variations of aerial VOC concentrations and emissions existed and were significantly affected by manure management systems, barn structural designs, and ventilation rates.Scientific research in this area has been mainly driven by odor nuisance, instead of environment or health concerns. Compared with other aerial pollutants in animal agriculture, the current scientific knowledge about VOCs at swine facilities is still very limited and far from sufficient to develop reliable emission factors. 相似文献