Biological treatment for waste streams from propellants and explosives manufacturing

The liquid waste streams from the propellants and explosives production operations are different from the standard industrial waste streams because of     

Process design for the production of a ceramic-like body from recycled waste glass

The influence of fabrication variables on the sintering behaviour of a ceramic-like body containing 90% recycled waste glass was inferred from measurements of some of the fired properties (moduli of rupture and elasticity, firing shrinkage, bulk density and porosity). Interpretation of these results in terms of viscous sintering theory indicates the relative influence on the sintering behaviour of factors such as particle size and distribution, clay binder content and plasticity, pressing pressure, heating/cooling rate, firing temperature and time, thus enabling the fabrication variables to be optimized. Comparison of the physical properties of the resulting glass-based bodies with those of commercial ceramic tile bodies indicates that the glass-based bodies are very comparable with the best ceramic tiles tested, and considerably better than several commercially-produced clay-based bodies.     

Process analysis and optimization of biodiesel production from soybean oil

The overall goal of this work is to design and optimize a biodiesel production process from soybean oil. To achieve this goal, several inter-connected activities were undertaken. First, an initial flowsheet for the process was synthesized. The performance of this flowsheet along with the key design and operating criteria were identified by conducting computer-aided simulation using ASPEN Plus. Various scenarios were simulated to provide sufficient understanding and insights and to select a base-case flowsheet. Next, mass and energy integration studies were performed to reduce the consumption of material and energy utilities, improve environmental impact, and enhance profitability. Capital cost estimation was carried out using the ICARUS Process Evaluator computer-aided tool linked to the results of the ASPEN Plus simulation. The operating cost of the process was estimated using the key information on process operation such as raw materials, utilities, and labor. A profitability analysis was carried out by examining the return on investment and the payback period. It was found that the cost of soybean oil is the largest contributor to the production cost. A sensitivity analysis was carried out to determine the effect of soybean oil prices on the process profitability.     

Process optimization for efficient dye removal by Aspergillus lentulus FJ172995

Response surface methodology involving three variables with five level second order central composite experimental design was employed to optimize conditions for maximum dye removal by Aspergillus lentulus FJ172995. The interaction between three variables; glucose, urea and initial dye concentration was studied and modeled for two responses: dye removal and biomass production. The results indicate that urea is the main factor influencing dye removal whereas glucose plays a major role in biomass production. Also, initial dye concentration has depreciative effect on dye removal thereby suggesting that for the treatment of effluent containing higher concentrations of dye, nutrient input should be increased. A high dye removal efficiency (99.97%) and high uptake capacity (97.54 mg/g) was obtained in 24h using optimum process variables.     

A proposed process scheme for recovering metal values from pigment manufacturing waste streams

 Effluents from pigment manufacturing operations contain highly toxic substances. These substances in their pure form are highly valuable industrial raw materials and their loss in the effluents is not only a pollution problem but also one implying economic loss. This article describes an approach, which highlights a policy that can allow elimination of a pollution problem with simultaneous economic benefits through recovery of the pollutants in readily marketable forms. This approach converts serious "liabilities into substantial assets" and is worth adopting in many cases. The case considered here is that of the effluent from a plant manufacturing the pigment, phthalocyanine green (PG). This effluent is highly acidic and contains copper and aluminium in chloride form. There is a serious disposal problem concerning this effluent. The work reported here was focussed on recovering the metal values in this effluent in a form which can be readily marketed. Particularly important is the fact that the aluminium value can be recovered in the form of zeolite 4A, which is an environment friendly additive in modern detergent formulations. Received: 1 July 1998 / Accepted: 30 September 1998     

Recovering value from waste: biomaterials production from marine shell waste

Marine shell waste is rich in calcium carbonate \((\hbox {CaCO}_{3})\), which can be a good source for the synthesis of hydroxyapatite (HAP). HAP is a potential component in bone tissue engineering as it possesses similar elements to bone structure. In this study, three different species of marine shells that are normally found in Malaysia, namely short-necked clam (Paphia undulate), blood cockle (Anadara granosa) and hard clam (Meretrix lyrata) were used to produce \(\hbox {CaCO}_{3}\) and HAP. The characterization results indicate that the produced \(\hbox {CaCO}_{3}\) consists of mainly aragonite polymorph. Subsequently, the produced \(\hbox {CaCO}_{3}\) was used as the calcium source for the formation of HAP through the wet slurry precipitation method. The results from the analyses on crystallinity, functional group, surface morphology and elemental analysis of the synthesized HAP powders that were obtained through X-ray diffraction (XRD), Fourier-transform infrared (FTIR), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) have confirmed that HAP is comparable with other studies. Overall, the results obtained through this study indicate that it is possible to produce \(\hbox {CaCO}_{3}\) and HAP from various marine-based shell waste through greener synthesis routes with less chemicals and reactiontime.     

Separation of critical radioactive and non-radioactive species from aqueous waste streams

The separation of radioactive and non-radioactive species from the simulated DOE neutralized current acid waste (NCAW) stream was studied. Cation and anion species were referred to their possible basic compounds, and divided into seven groups (nitrate, phosphate, sulfate, fluoride, nitrite, carbonate, and hydroxide). The nitrate group (the major anion in the DOE waste streams) contains several cations species, while the rest of the groups are only in the form of sodium. The precipitation measurements were conducted in three experimental stages. In the first stage, the precipitation of sodium sulfate, sodium phosphate, sodium-sulfate-phosphate, and aluminum nitrate systems were studied using isopropylamine (IPA) as a precipitation solvent. The objectives of this stage were to evaluate the precipitation ability of IPA in precipitating these compounds individually, and to validate the consistency of the analytical instruments and the employed experimental procedure. Tests performed on the acquired data indicated a high level of experimental consistency. The removal of phosphate, sulfate and aluminum were very high. In the second stage, the precipitation studies were conducted on the: (1) nitrate group alone; (2) binary groups containing the groups of nitrate-phosphate, nitrate-sulfate, nitrate-fluoride, nitrate-nitrite, and nitrate-carbonate; (3) combined nitrate, phosphate, sulfate, and fluoride groups and (4) combined nitrate, phosphate, sulfate, fluoride, nitrite, and carbonate groups. IPA was used as a precipitation solvent. The objectives of this stage were to evaluate the interactions of these groups in the absence of the hydroxide group (e.g. DOE acid-dissolved sludge and acidified supernate streams), and the influence of such interactions on the individual removal of the targeted species. The removal of the aluminum, phosphate, fluoride, and alkaline cations were significantly high (reached 99.9%). The removal of sulfate were moderately high (reached 87%), and the removal of nitrate and alkali cations including cesium were to some extent low (reached about 50%).In the third stage, the precipitation of inorganic species from the simulated NCAW stream was studied using IPA and ethylamine (EA). The precipitation process is very feasible for reducing the radioactivity contents of alkaline cations. However, the process is less effective in separating alkali cations including cesium. The removal of polyvalent transition metals such as aluminum ion is negatively influenced by the significant presence of hydroxide. While the process is effectively capable of separating phosphate, fluoride, and sulfate, it is significantly less effective in separating nitrate and nitrite. A previously derived thermodynamics framework was used to model the precipitation measurements. The framework provided two predictive equations (the 2-Suffix and 3-Suffix equations). Both equations were reasonably adequate for predicting the solubility phase behavior of tested inorganic species in a mixed-solvents mixture as well as for estimating optimum interaction parameters. However, the 3-Suffix equation was better than the 2-Suffix equation. The parameters were useful for estimating the: (1) precipitation fractions (%P) of the studied species, for instance, at different concentration levels of similar targeted species, or in different waste streams with similar or approximate abundance of species, or at different solvents volume ratio (V(r)) where no experimental data are available.     

Regulatory framework for the thermal treatment of various waste streams

Since 1990, regulations and standards have changed considerably. This article is an update of the regulatory requirements for the thermal treatment of various waste streams. The waste categories covered, along with the laws they are governed under, include: Hazardous waste under Subtitle C of the Resource Conservation and Recovery Act (RCRA) and under the Clean Air Act; municipal solid waste under Subtitle D of the RCRA; medical waste under Subtitle J of the RCRA; Superfund waste under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA); toxic waste under the Toxic Substances Control Act (TSCA); and sludge waste under the Clean Water Act (CWA).     

Comparison of ecological footprint for biobased PHA production from animal residues utilizing different energy resources

Realizing a sustainable development of our planet requires a reduction of waste production, harmful emissions, and higher energy efficiency as well as utilization of renewable energy sources. One pathway to this end is the design of sustainable biorefinery concepts. Utilizing waste streams as raw material is gaining great importance in this respect. This reduces environmental burden and may at the same time contribute to economic performance of biorefineries. This paper investigates the utilization of slaughtering waste to produce biodegradable polyesters, polyhydroxyalkanoates (PHA), via bioconversion. PHA are the target product while production of high quality biodiesel along with meat and bone meal (MBM) as by-products improves the economic performance of the process. The paper focuses on ecological comparison of different production scenarios and the effect of geographical location of production plants taking different energy production technologies and resources into account; ecological footprint evaluation using Sustainable Process Index methodology was applied. Keeping in mind that the carbon source for PHA production is produced from waste by energy intensive rendering process, the effect of available energy mixes in different countries becomes significant. Ecological footprint results from the current study show a bandwidth from 372,950 to 956,060 m²/t PHA production, depending on the energy mix used in the process which is compared to 2,508,409 m²/t for low density polyethylene.     

一种有效的数据流最大频繁模式挖掘算法

针对频繁项集挖掘存在数据和模式冗余的问题,对数据流最大频繁项集挖掘算法进行了研究。针对目前典型的数据流最大频繁模式挖掘算法DSM-MFI存在消耗大量存储空间及执行效率低等问题,提出了一种挖掘数据流界标窗口内最大频繁项集的算法MMFI-DS,该算法首先采用SEFI-tree存储包含在不断增长的数据流中相关最大频繁项集的重要信息,同时删除SEFI-tree中大量不频繁项目,然后使用自顶向下和自底向上双向搜索策略挖掘界标窗口中一系列的最大频繁项集。理论分析与实验表明,该算法比DSM-MFI算法具有更高的效率,并能节省存储空间。     

Wet air oxidation — A treatment means for aqueous hazardous waste streams

Wet air oxidation (WAO) is a process in which dissolved or suspended oxygen-demanding components of a wastewater are oxidated at elevated temperature and pressure using an oxygen-containing gas such as air bubbling through the aqueous phase. In this paper the increasing use of WAO in detoxification of hazardous wastes is described. The cost of WAO is compared with that of incineration. Various present day applications of WAO are described in detail.     

Approaches for the treatment of waste streams of the aluminium anodising industry

The aluminium anodising industry is an important industrial sector that invariably generates great amounts of different waste streams. Classical and especially new-developing technologies dealing with them are reviewed. Innovative methods are mainly based on engineering geochemical processes, looking for the recovery of resource materials and the reduction of emissions to the environment. These represent a promising alternative to the classical method (neutralisation process and anodising mud disposal) which is an end-of-pipe solution. Among the treatments recently proposed, there are the use of anodising mud in the manufacture of refractory bodies, and the synthesis of useful minerals from the wastewaters arising from the etching, anodising and brightening processes. The viability of the application of such methods in the treatment of waste streams of the aluminium anodising industry is discussed, pointing out the main shortcomings and benefits of each of them. For those methods appearing environmentally friendly the process cost and the actual marketability of the final products should be determinant on their near future applicability.     

An efficient approach for reliability-based topology optimization

This article presents an efficient approach for reliability-based topology optimization (RBTO) in which the computational effort involved in solving the RBTO problem is equivalent to that of solving a deterministic topology optimization (DTO) problem. The methodology presented is built upon the bidirectional evolutionary structural optimization (BESO) method used for solving the deterministic optimization problem. The proposed method is suitable for linear elastic problems with independent and normally distributed loads, subjected to deflection and reliability constraints. The linear relationship between the deflection and stiffness matrices along with the principle of superposition are exploited to handle reliability constraints to develop an efficient algorithm for solving RBTO problems. Four example problems with various random variables and single or multiple applied loads are presented to demonstrate the applicability of the proposed approach in solving RBTO problems. The major contribution of this article comes from the improved efficiency of the proposed algorithm when measured in terms of the computational effort involved in the finite element analysis runs required to compute the optimum solution. For the examples presented with a single applied load, it is shown that the CPU time required in computing the optimum solution for the RBTO problem is 15–30% less than the time required to solve the DTO problems. The improved computational efficiency allows for incorporation of reliability considerations in topology optimization without an increase in the computational time needed to solve the DTO problem.     

Use of 3D printing for biofuel production: efficient catalyst for sustainable biodiesel production from wastes

This work deals with the sustainable biodiesel production from low-cost renewable feedstock (waste and non-edible oils) using a heterogeneous catalyst constituted by potassium loaded on an amorphous aluminum silicate naturally occurring as volcanic material (pumice). The main challenge to biodiesel production from low-quality oils (used oils and greases) is the high percentage of free fatty acids (FFAs) and water in the feedstock that causes undesirable side reactions. The catalytic materials studied were tested in the transesterification reaction when using low-quality oils containing a high proportion of free fatty acids (FFAs) and water. Results indicated that the amount of acid and basic sites on the catalytic surface increases upon increasing potassium loading in the catalyst, displaying better performance for biodiesel production. Indeed, the modification of the aluminum silicate substrate upon potassium incorporation results in a catalytic material containing both acidic and basic sites, which are responsible for both triglycerides transesterification and FFA esterification reactions. The studied catalyst not only showed good performance in the biodiesel production reaction but also good tolerance to FFA and water contained in the feedstock for biodiesel production. The catalytic material was microstructured by 3D printing in order to design a catalytic stirring system with high mechanical strength, efficient and reusable. The use of 3D printing in biofuel production is a novelty that brings good solutions for catalyst production.     

拓扑与形状优化用于有效的产品设计

 介绍了基于有限元法(FEM)的计算机辅助结构优化方法． 拓扑优化有助于设计新零件的形状，形状优化则通过表面几何形状的局部调整改善零件的刚度或使用寿命．