Influence of different textile fibers on characterization of dyeing wastewater and final effluent

Textile industry needs to recover and reuse its wastewater as to fulfil the demand of increasingly strict regulations. The characterization of dyeing wastewater samples according to textile fiber and final textile effluent enables the application of different treatment methods. This study aims to characterize dyeing wastewater in black color of polyamide, polyester, and viscose fibers and final textile effluent. Samples were collected and characterized completely for major pollution indicator parameters. Dyeing wastewater of polyester showed higher values for some parameters, e.g., 4994.44% (49,944,400 mg L^?1 and 917 NTU) of turbidity and 4100.00% of phenol when compared to dyeing wastewater of other fibers. Other parameters such as pH, alkalinity, color, phosphorus, nitrogen, sulfides, chlorides, oil and grease, dissolved solids, and chemical and biochemical oxygen demand were also assessed. In addition to individual characterization, this study also presents a correlation of the contribution of each parameter to the final textile effluent. Although dyeing wastewater of polyamide contributes the most in terms of quantity for the final effluent, this study revealed that dyeing wastewater of polyester influenced the most on the final composition of the textile wastewater when evaluating color, turbidity, total iron, biochemical oxygen demand, chemical oxygen demand, phenol, mercury, oil and grease, and total phosphorus. The present study is focused on bringing new insights to provide future research with other strategies to improve the treatment of dyeing wastewater. In addition, some suggestions are also given for wastewater treatments according to type of textile fiber.     

Carbon Storage in Soil Size Fractions Under Two Cacao Agroforestry Systems in Bahia, Brazil

Shaded perennial agroforestry systems contain relatively high quantities of soil carbon (C) resulting from continuous deposition of plant residues; however, the extent to which the C is sequestered in soil will depend on the extent of physical protection of soil organic C (SOC). The main objective of this study was to characterize SOC storage in relation to soil fraction-size classes in cacao (Theobroma cacao L.) agroforestry systems (AFSs). Two shaded cacao systems and an adjacent natural forest in reddish-yellow Oxisols in Bahia, Brazil were selected. Soil samples were collected from four depth classes to 1 m depth and separated by wet-sieving into three fraction-size classes (>250 μm, 250–53 μm, and <53 μm)—corresponding to macroaggregate, microaggregate, and silt-and-clay size fractions—and analyzed for C content. The total SOC stock did not vary among systems (mean: 302 Mg/ha). On average, 72% of SOC was in macroaggregate-size, 20% in microaggregate-size, and 8% in silt-and-clay size fractions in soil. Sonication of aggregates showed that occlusion of C in soil aggregates could be a major mechanism of C protection in these soils. Considering the low level of soil disturbances in cacao AFSs, the C contained in the macroaggregate fraction might become stabilized in the soil. The study shows the role of cacao AFSs in mitigating greenhouse gas (GHG) emission through accumulation and retention of high amounts of organic C in the soils and suggests the potential benefit of this environmental service to the nearly 6 million cacao farmers worldwide.     

Degree of phosphorus saturation of an Oxisol amended with biosolids in a long-term field experiment

When applied to agricultural soils, phosphate fertilizers and the mineral or organic compounds present in solid and/or liquid waste may raise phosphorus (P) content and increase soil P saturation. The degree of phosphorus saturation (DPS) is a good indicator of potential P loss from agricultural soils. The purpose of this study was to calculate the DPS of samples from an Oxisol amended for 5 years with biosolids and mineral fertilizer. DPS was calculated based on P, iron, and aluminum extracted by ammonium oxalate and oxalic acid (DPS_ox) or by Mehlich-1 solution (DPS_M1). Treatments included NPK mineral fertilization (175 kg ha^?1 of P), B1?=?19.02 t ha^?1 of biosolids (350 kg ha^?1 of P), B2?=?38.17 t ha^?1 of biosolids (703 kg ha^?1 of P), B3?=?76.26 t ha^–1 of biosolids (1,405 kg ha^?1 of P), and a control (no P added). Water-extractable P (WEP) was also measured. Critical levels of DPS_ox and DPS_M1 (21 and 24 %, respectively) were only achieved in the topsoil (0–0.1 m) at the highest biosolid dose. Concentration of WEP was positively correlated to DPS_ox and DPS_M1. The DPS_M1 method may be an alternative to DPS_ox for assessing the environmental risk of P loss from soil into surface runoff.     

Forensic Evaluation of Metals (Cr,Cu, Pb,Zn), Isotopes (δ13C and δ15N), and C:N Ratios in Freshwater Sediment

A forensic approach was used to evaluate sediments from Portão Stream, including analysis of metals, carbon (C) and nitrogen (N) stable isotopes, and C:N ratios. Samples collected at various points located along the stream were tested in order to investigate a possible illegal leachate input. The studied stream is heavily impacted by sewage and industrial discharges from two cities along its course. Among the metals analyzed, chromium (Cr) was noticeably the main pollutant, showing the highest levels, above regulatory limits, downstream from some potential sources of effluents enriched with this metal. Isotope analyses revealed a general trend of depletion in the heavier isotope along the stream for C and N. The exception was one point near a hazardous waste landfill, where relatively more enriched δ¹³C and δ¹⁵N values were found. The isotope and metal analysis results indicated that this site was affected by a particular source, demonstrating the combination of these parameters could be used for the discrimination of sources in a heavily polluted stream. Nevertheless, further investigations are necessary to provide a comprehensive evaluation of the biogeochemical processes involved in the incorporation of leachate in sediments to use this analysis as evidence for the illegal leachate discharge.     

Integrated hydrologic–economic decision support system for groundwater use confronting climate change uncertainties in the Tunuyán River basin,Argentina

This study presents an integrated hydrologic–economic model as decision support system for groundwater use and incorporates uncertainties of climate change. The model was developed with the Vensim software (Ventana Systems) for system dynamic simulations. The software permitted the integration of economic variables along with hydrologic variables, in a unified format with the aim of evaluating the economic impacts of climate change on arid environments. To test the model, we applied it in one of the upper Tunuyán River sub-basin, located in the Mendoza Province (Argentina), where irrigation comes from groundwater. The model defines the best mix of crops and the total land use required to maximize the total river sub-basin monetary income, considering as a limit the amount of water that does not exceed the natural annual aquifer recharge. To estimate the impacts of climatic changes, four scenarios were compared: the business as usual (with the number of existing wells) in a dry year with a temperature increase of 4 °C; the business as usual in a wet year with an increase in temperature of 1.1 °C; an efficient use of wells in a dry year and a temperature increase of 4 °C and an efficient use of wells in a wet year with a temperature increase of 1.1 °C. Outputs calculated by the model were: land use per crop, total sub-basin net benefit, total sub-basin water extraction, water extraction limit depending on river discharge and total number of wells required to irrigate the entire area. Preliminary results showed that the number of existing wells exceeded the optimized number of wells required to sustainably irrigate the entire river sub-basin. Results indicated that in an average river discharge year, if wells were efficiently used, further rural development would be possible, until the limit of 350 million m³ of water extraction per year was reached (650 million m³ for a wet year and 180 million m³ for a dry year). The unified format and the low cost of the software license make the model a useful tool for Water Resources Management Institutions, particularly in developing countries.     

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.