Polyfunctional Plants for Industrial Waste Disposal—Part II: Economics and Model Evaluation

ABSTRACT

This is the second part of a two-part paper dealing with the preliminary design and costing of polyfunctional waste treatment plants. In this article, we present some criteria for estimating capital investment and annual operating costs of polyfunctional plants for industrial waste treatment. The process and equipment design methods presented in Part I of this article, together with the economic approach proposed here, allow for complete technical/economic analyses. The overall mathematical model appears to be a useful tool in economic feasibility studies. The accuracy of the developed computer mathematical model has been demonstrated, referring to actual cost data from the literature.     

Cost-Effectiveness Analysis of Waste Gas Treatment Plants for the Glass Industry

ABSTRACT

Cost-effectiveness of different plant solutions for glass furnace waste gas cleaning is compared in the present paper. Plant arrangements based on electrostatic precipi-tator or fabric filter dust collectors and wet, semi-dry, or dry processes for acid gas removal have been considered. A critical survey of each solution's advantages and disadvantages has been presented, taking into account both effectiveness and costs resulting from each available system. Finally, a quantitative assessment has been provided with reference to a case study involving actual float glass production lines at SIV plants located in northern and central Italy.     

Economic Comparison of Emission Control Systems for Glass Manufacturing Furnaces with Heat Recovery

ABSTRACT

Glass manufacturing, like other process industries, is faced with air pollution compliance problems due to ever stricter emission limits. Several waste gas cleaning equipment options are available for air pollution control (APC) in glass plants, the most common arrangements being based on electrostatic precipitator (ESP) or fabric filter (FF) dust collectors and semi-wet or dry processes for acid gas removal. However, several counteracting aspects affect the choice of gas cleaning technologies, which are confirmed by the discrepancies encountered in actual suppliers' bids. In this paper, the main pollution control options are analyzed by carrying out a critical comparison under the cost-effectiveness point of view to select the lowest cost arrangement considering capital investment, operating expenses, and energy-saving revenues from heat recovery processes. The analysis is carried out with reference to a case study involving actual float glass production lines at Pilkington plants in Italy.     

Adsorption of As(III) on chitosan-Fe-crosslinked complex (Ch-Fe)

It was reported the adsorption of As(III) on the surface of the chitosan-Fe-crosslinked complex. Theoretical correlation of the experimental equilibrium adsorption data for As(III)/Ch-Fe system is best explained by the non-linearized form Langmuir-Freundlich isotherm model. At optimum conditions, pH 9.0, the maximum adsorption capacity, calculated using the Langmuir-Freundlich isotherm model was 13.4 mg g⁻¹. The adsorption kinetics of As(III) onto Ch-Fe are described by the pseudo-first-order kinetic equation. The results of the Mössbauer spectroscopy showed that there is no redox process on the surface of the adsorbent.     

Determination of lipid peroxidation and cytotoxicity in calcium, magnesium, titanium and hectorite (SHCa-1) suspensions

This paper reports data on the relative ability of CaO, CaCl₂, MgO, MgCl₂, TiO₂, and hectorite (SHCa-1) to induce oxidative stress (as determined by lipid peroxidation, LP) in biological matrices. The effectiveness of structural (oxide form) versus soluble Ca and Mg to induce LP is compared. An assessment on cytotoxicity as affected by soluble and structural Ca, Mg, TiO₂ and SHCa-1 is also addressed. LP was screened and monitored using the Thiobarbituric Acid Reactive Substances (TBARS). The extent of TBARS production was found to vary with the type and initial concentration of the soluble or structural cation, Ca or Mg respectively. Obtained results showed higher magnitude values for the latter set of experiments. In the presence of TiO₂ no significant TBARS production was detected pointing out a negligible effect of TiO₂ on LP. At solid concentrations ca. 100 ppm, CaO appears to be more effective than SHCa-1 to induce LP. By contrast at ca. 25 ppm, MgO appears to be more effective than the clay mineral. The SHCa-1 LP-inducing activity has been proven to closely relate to structural Ca. The prevalence of mechanisms that may induce LP but not cytotoxicity (as determined by cell growth inhibition) was also addressed. Results on cell growth inhibition as affected by soluble and structural Ca, Mg, TiO₂ and hectorite provide evidence to support that structural Ca or Mg brings about significantly higher variations than soluble Ca.     

Occurrence and distribution of pharmaceuticals in surface water, suspended solids and sediments of the Ebro river basin, Spain

The occurrence of 43 pharmaceuticals belonging to predominant therapeutic classes and their distribution in surface water, suspended solids and sediments has been investigated in the Ebro river basin in the Northeast of Spain. WWTP effluents were found to be a main source of contamination and the spatial distribution was affected by the river flow at the sampling point and corresponding dilution factor, resulting in higher concentrations and higher loads in small tributary rivers than in the Ebro river. The study showed that some compounds are preferentially found bound to suspended solids and not detected in river water. Generally, compounds with basic characteristics (pKa > 7) showed higher tendency to bind to suspended solids. The sediment samples generally presented lower concentrations than suspended solids.     

Atmospheric fate of non-volatile and ionizable compounds

A modified version of the Multimedia Activity Model for Ionics MAMI, including two-layered atmosphere, air-water interface partitioning, intermittent rainfall and variable cloud coverage was developed to simulate the atmospheric fate of ten low volatility or ionizable organic chemicals. Probabilistic simulations describing the uncertainty of substance and environmental input properties were run to evaluate the impact of atmospheric parameters, ionization and air-water (or air-ice) interface enrichment.The rate of degradation and the concentration of OH radicals, the duration of dry and wet periods, and the parameters describing air-water partitioning (K_AW and temperature) and ionization (pK_a and pH) are the key parameters determining the potential for long range transport. Wet deposition is an important removal process, but its efficiency is limited, primarily by the duration of the dry period between precipitation events.Given the underlying model assumptions, the presence of clouds contributes to the higher persistence in the troposphere because of the capacity of cloud water to accumulate and transport non-volatile (e.g. 2,4-D) and surface-active chemicals (e.g. PFOA). This limits the efficiency of wet deposition from the troposphere enhancing long-range transport.     

Use of recycled fine aggregate in concretes with durable requirements

The use of construction waste materials as aggregates for concrete production is highly attractive compared to the use of non-renewable natural resources, promoting environmental protection and allowing the development of a new raw material. Several countries have recommendations for the use of recycled coarse aggregate in structural concrete, whereas the use of the fine fraction is limited because it may produce significant changes in some properties of concrete. However, during the last decade the use of recycled fine aggregates (RFA) has achieved a great international interest, mainly because of economic implications related to the shortage of natural sands suitable for the production of concrete, besides to allow an integral use of this type of waste. In this study, the durable behaviour of structural concretes made with different percentage of RFA (0%, 20%, and 30%) is evaluated. Different properties related to the durability of concretes such as absorption, sorptivity, water penetration under pressure, and carbonation are determined. In addition, the results of compressive strength, static modulus of elasticity and drying shrinkage are presented. The obtained results indicate that the recycled concretes have a suitable resistant and durable behaviour, according to the limits indicated by different international codes for structural concrete.     

Microplastic distribution in surface sediments along the Spanish Mediterranean continental shelf

Environmental Science and Pollution Research - Microplastics (MPs) are widely recognised as a contaminant of emerging concern in the marine environment. This work provides original data of the...