共查询到20条相似文献,搜索用时 15 毫秒
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M. N. Chavan N. D. Dandi M. V. Kulkarni A. B. Chaudhari 《Water, air, and soil pollution》2013,224(11):1-10
Humic acids (HA) are known as the precursors of carcinogenic compounds formed by the disinfection of drinking water. While conventional treatments were found to be inefficient HA removal processes in drinking water, advanced oxidation processes have been proven to have a significant effect in the treatment of HA. The degradation of HA was investigated using nano-sized zinc oxide (ZnO)/laponite composite (NZLC). The reactions occurred in a UVC reactor by considering following variables: pH, initial HA concentration, catalyst loading, addition of hydrogen peroxide (H2O2), and catalyst reuse. Water samples containing HA were analysed by ultraviolet/visible spectrophotometer and high-performance size-exclusion chromatography. Initial HA concentrations were tested by the Langmuir–Hinshelwood model with k and K ads values, determined to be 0.126 mg/L.min and 0.0257 L/mg, respectively. The change in pH affected the HA degradation efficiency by the photocatalytic activity where it was higher under acidic conditions rather than alkaline ones. Optimal catalyst loading was proved to be a constrained factor in influencing the photocatalytic efficiency: the increase of catalyst concentration enhanced the HA decomposition efficiency up to an optimum value of 20 g/L, where there was no further degradation with excess loading. The addition of H2O2 was investigated through homogenous and heterogeneous photocatalysis, and, heterogeneous photocatalysis showed higher removal efficiency due to the combined effect of both catalysts and H2O2. Finally, NZLC was effective for reuse and exhibited an excellent stability after six times of usage. 相似文献
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El-Masry Mohamed H. Sadek Olfat M. Mekhemer Wafaa K. 《Water, air, and soil pollution》2004,158(1):373-385
The purification of raw surface water from its organic, inorganic and microbial content using the electro-coagulation method was investigated. Batch coagulation experiments were conducted using the jar-test method. A pair of aluminum electrodes (suspended in the jar) was charged with low voltage current for releasing aluminum ions in the raw water to precipitate the suspended matter. The optimum current density was 0.6325 mA cm–2. The coagulation efficiency was evaluated by determining the turbidity of treated water. The efficiency reduction in raw water turbidity was 90%, leading to a change in water Zeta potential from –85 mV (before treatment) to –40 mV (after treatment), i.e. the particles tended to be destabilized and the coagulation process became predominant. Water contents of nitrates, phosphates and sulfates were considerably reduced by 77.5, 83.3 and 20.0%, respectively. Also, this method is effective in reducing both the total viable bacterial count (TVBC) and total coliforms (TC) by a ratio of 1/104 and 1/103, respectively. 相似文献
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Muhammad Nawaz Shahbaz Khan Hakoomat Ali Muhammad Ijaz Muhammad Umer Chattha Muhammad Umair Hassan 《Communications in Soil Science and Plant Analysis》2019,50(10):1239-1249
Excessive and inappropriate use of fertilizers is a key factor of low sugarcane yield and degradation of soil. A two-year (2013–14 and 2014–15) field study was conducted to assess the impact of combined application of organic and inorganic fertilizers on sugarcane at research farm of Shakarganj Sugar Research Institute, Jhang, Pakistan. Experiment was conducted under randomized complete block design with three replications. Treatments were used as control (no exogenous application), spent wash (160 t ha?1), (nitrogen, phosphorus and potassium) NPK (168:112:112 kg ha?1), spent wash (120 t ha?1) + NPK (42:28:28 kg ha?1), spent wash (80 t ha?1) + NPK (84:56:56 kg ha?1), spent wash (40 t ha?1) + NPK (126:84:84 kg ha?1), and spent wash (160 t ha?1) + NPK (42:28:28 kg ha?1). Application of spent wash @ 80 t ha?1 + NPK @ 84:56:56 kg ha?1 resulted maximum crop growth rate (11.35 g m?2 d?1), leaf area index (7.78), and net assimilation rate (2.53 g m?2 d?1). Maximum number of millable canes (14), weight per stripped cane (0.90 kg), stripped cane yield (117.60 t ha?1) and unstripped cane yield (141.25 t ha?1) were observed with spent wash @ 80 t ha?1 + NPK @ 84:56:56 kg ha?1, followed by sole fertilizer application @ 168:112:112 kg NPK ha?1 and spent wash @160 t ha?1 + NPK @ 42:28:28 kg ha?1. Similar trend was observed regarding quality parameters. The maximum benefit–cost ratio (1.80) was achieved with integrated application of spent wash @ 80 t ha?1 + NPK @ 84:56:56 kg ha?1. 相似文献
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黎毓鹏 《广西农业生物科学》1998,(Z1)
在实际的机构优化设计问题中,求解优化问题的切实可行的方法显得至关重要。本文以一个四连杆机构作为实例,立足编程的需要,对在约束优化问题上的内点惩罚函数方法和Pow-ell方法进行了多方面的探讨。 相似文献
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I.G. Mason 《Compost science & utilization》2013,21(3):207-214
This paper reviews the composition and performance of simulated feedstock mixtures previously employed in composting research, and presents a new simulated feedstock. The new feedstock was prepared using readily available dry ingredients — ostrich feed pellets, office paper, finished compost and woodchips — representing the substrate, amendment, seed, and bulking agent components of a composting mixture respectively. The design criteria chosen were a) a substrate plus amendment C:N ratio of 30:1, b) an energy ratio of > 800 cal/g-H2O, c) a water ratio of < 8 g-H2O/g-BVS, d) a wet bulk density of < 600 kg/m3 and e) a moisture content of 60% (w/w). Resultant final proportions of the substrate:amendment:seed:bulking-agent:added-water mix were 0.071:0.098:0.009:0.267:0.555 (w/w). When composted in a controlled temperature difference (CTD), forced-aeration reactor operated with condensate return, the mixture was shown to self-heat rapidly and remain at realistic temperatures for extended periods. Thermophilic temperatures were reached within 22-33 h of start-up, following lag periods of 13-22 h, and maintained for up to 34 d. Final compost characteristics were consistent with a normal composting process. It is suggested that future variations in the simulated feedstock composition could be made, and proposed that use of this type of feedstock would facilitate future experimental work associated with composting kinetics and temperature profile modeling. 相似文献
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长江流域山区以土石山地为主,山高坡陡,土层薄,石料丰富,基本农田建设以修筑石坎梯田为主。对梯形断面石坎进行稳定分析,认为最大稳定坎高为262m。从物理概念入手,建立了以坎高H为决策变量,以综合费用损失最小为目标的石坎梯田优化设计数学模型。优化设计施工实例表明,优化设计方案与农民常规修筑方法相比,具有田块大、田面平、田坎占地少且稳定、节省修筑投工等优点。 相似文献
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J.A. Buswell 《Compost science & utilization》2013,21(3):31-36
? Several approaches involving the use of spent mushroom substrate (SMS) for bioremediation purposes warrant further investigation. SMS has important potential for the biological treatment of contaminated soils in situ and offers an attractive technology for the decontamination of land sites used for the disposal of hazardous wastes. Development of the bioremediation potential of SMS, coupled with the well-documented environmental benefits of SMS (e.g. provision of plant nutrients, neutralization of soil acidity, improvement of water quality), should serve to enhance the value of SMS as an additional source of revenue to the mushroom grower. large scale bioremediation system involves the seeding of contaminated sites with microbial inoculants. Apart from cost considerations (i.e. they must be cheap to produce to have any practical value), bioremediation inoculants should be selected for their degradative capacity (ability to totally mineralise the contaminant, broad substrate specifity). The stability of that capacity and their survival properties under the conditions that prevail at the contaminated site also are important, and they should not possess any undesirable characteristics such as pathogenicity and allergenicity. 相似文献
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Isaac Fern��ndez Elzbieta Plaza Jozef Trela Bengt Hultman Ram��n M��ndez 《Water, air, and soil pollution》2011,215(1-4):299-309
The influence of the operational variables on the Anammox process has been generally researched considering each variable separately. However, the optimization of the process also requires the identification of the more significant variables and their possible interactions. Response surface models were successfully applied to evaluate the performance of the Anammox process in a deammonification system (i.e., one-stage biofilm Anammox process) taking into account the combined effects caused by two sets of three variables. Specific Anammox activity was measured by a manometric method and used as the response variable. The obtained models pointed out that the significant variables were the temperature, the value of pH, and the ratio between the unionized species of the substrates (free ammonia and free nitrous acid (FA/FNA)). There were interactions among them caused by chemical equilibriums. Total nitrogen concentration and ammonium concentration were found to be not significant in the tested range. According to the models, the optimum values of temperature, pH, and free ammonia to free nitrous acid ratio within the test ranges were, respectively, 30°C, 7.0, and 0.3. Further research at higher temperatures and lower values of pH and FA/FNA ratios would be necessary in order to find the absolute optimum conditions for the process. The obtained model can be also useful in order to develop control strategies that take into account the significant variables and their optimum ranges. A strategy to control deammonification reactors has been proposed, according to the results of the modeling. 相似文献
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Maryam Zolghadr Sergei Zuyev 《Journal of Agricultural, Biological & Environmental Statistics》2016,21(4):663-683
The paper develops methods to construct a one-stage optimal design of dilution experiments under the total available volume constraint typical for biomedical applications. We consider various design criteria based on the Fisher information both in Bayesian and non-Bayesian settings and show that the optimal design is typically one-atomic meaning that all the dilutions should be of the same size. The main tool is variational analysis of functions of a measure and the corresponding steepest descent-type numerical methods. Our approach is generic in the sense that it allows for inclusion of additional constraints and cost components, like the cost of materials and of the experiment itself. 相似文献
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Haiyan Huang Guanglei Cheng Lan Chen Xiaoqiang Zhu Heng Xu 《Water, air, and soil pollution》2009,203(1-4):53-63
In this paper, Taguchi method was applied to determine the optimum condition for Pb (II) removal from aqueous solution by spent Agaricus bisporus. An orthogonal array experiment design (L9(34) which is of four control factors (pH, t (contact time), m (sorbent mass), and C 0 (initial Pb (II) concentration)) having three levels was employed. Biosorption capacity (mg metal/g biosorbent) and percent removal (%) were investigated as the quality characteristics to be optimized. In order to determine the optimum levels of the control factors precisely, range analysis and analysis of variance were performed. The optimum condition for biosorption capacity was found to be pH?=?5.00, t?=?5.0 h, m?=?0.010 g, and C 0?=?50 mg/L. And for percent removal, the optimum condition was found to be pH?=?4.00, t?=?4.0 h, m?=?0.100 g, and C 0?=?50 mg/L. Under these optimum conditions, biosorption capacity and percent removal can reach 60.76 mg/g and 80.50%, respectively. 相似文献
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Mushroom farmers have large quantities of spent mushroom substrate after their crops are harvested. This material is used for a variety of purposes including the growth of field crops. SMS was incorporated into a poor quality soil before planting 90-day corn. Field plots were established where spent mushroom substrate (SMS) was incorporated at 22.5, 45.0 or 90.0 kg m?1, plus an untreated control on each of three years. Analysis of SMS indicates its nutrient level was 0.9-0.6-1.0 (N-P-K). Starter fertilizer was applied at planting along with an insecticide, but no herbicide. No additional fertilizer was used. Corn yields were significantly higher in SMS amended plots and the nitrogen content of both grain and stover was significantly higher than the control. Surface runoff water quality values from SMS amended soil were in the same range as those from the control treatments, the plots that received no SMS. Annual incorporation of up to 90 kg m?2 of SMS into land planted to corn did not degrade the quality of surface water. Nutrients were retained in the SMS soil matrix and were, apparently, used as nutrients by the corn plants. Surface runoff was very low in ammonia nitrogen, CBOD, and chlorides. Use of SMS as an exclusive soil nutrient/soil ameliorant in corn production resulted is exceptionally good yields and quality. 相似文献
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Mimi Suliza Muhamad Nuramidah Hamidon Mohd Razman Salim Zulkifli Yusop Woei Jye Lau Tony Hadibarata 《Water, air, and soil pollution》2018,229(7):222
In this work, the effects of various operating parameters (pressure, pH, BPA concentration, and filtration time) toward bisphenol A (BPA) removal via ultrafiltration (UF) membrane system were investigated using response surface methodology (RSM). Historical data design of RSM was used to obtain the interaction between variables and response as well as optimizing the process. The analysis of variance (ANOVA) showed that the third-order polynomial model was significant in which pH and filtration time were identified as significant terms that influence BPA removal. The 3D response surface plots revealed the two-factor interaction between independent and dependent variables. The optimization process of the model predicted optimum conditions of 99.61% BPA removal at 1 bar, pH 6.7, 10 μg/L BPA concentration, and 10-min filtration time. The predicted optimum conditions for BPA removal were consistent with the obtained experimental values, indicating reliable application of historical data design RSM for modeling BPA removal in UF membrane system. 相似文献
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生物质压块挤压部件结构参数的优化设计 总被引:2,自引:0,他引:2
根据对物质物料挤压过程的理论分析和实测数据,建立了挤压部件优化设计的数学模型,在模型中,以挤压系统的单耗为目标函数,根据某些设计要求推导了约束条件,并以挤压部件的主要参数如螺杆直径、螺距、螺槽深等作为设计变量。应用优化技术对部件的主要结构参数进行了优化设计,经验证表明,使用优化参数的挤压部件生产能力和功耗都有明湿地改进。 相似文献