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The study explores the aftermath of a wastewater reservoir failure in a phosphate fertilizer industry, resulting in the release of acidic water containing phosphorus and sulfate compounds into the Ashalim stream's Nature Reserve in the Judean desert, which affected the soil surface biological crusts (biocrusts) layer. The study aims to examine contamination effects on biocrusts over 3 years at two research sites along the stream, compare effects between contaminated sites, assess rehabilitation treatments, and examine their impact on soil characteristics. Hypotheses suggest significant damage to biocrusts due to acidic water flow, requiring human intervention for accelerated restoration. The results indicate adverse effects on biocrust properties, risking its key role in the desert ecosystem. The biocrust layer covering the stream's ground surface suffered significant physical, chemical, and biological damage due to exposure to industrial process effluents. However, soil enrichment treatments, including biocrust components and organic material, show promising effects on biocrust recovery. [ABSTRACT FROM AUTHOR]

The present research assists in resolving the issues allied with the disposal of industrial solid wastes/industrial by-products (IBPs) by developing sustainable IBPs based cement mortars. The applicability of IBPs as a feasible alternative to river sand in cement mortar has been evaluated by investigating the synergy among the ingredients, resulting engineering properties and microstructural developments at early and late curing ages. The study could effectively substitute 30% volume of river sand with bottom ash and 50% in the case of slag sand mortars. The experimental outcomes disclose that the practice of IBPs as fine aggregate enhances the engineering properties of mortar and the optimum replacement level lies at 10% and 40% usage of bottom ash and slag sand, respectively. The advanced characterization studies and particle packing density illustrate the refinement of pores by void filing action and accumulation of additional hydration products through secondary hydration reactions. The consumption of portlandite followed by increased hydration products formation observed through thermogravimetric analysis, X-ray diffraction analysis and energy dispersive X-ray spectroscopy that confirmed the contribution of finer fractions of IBPs to secondary hydration reactions. This constructive development was also observed from the lowering of wavenumber corresponding to Si–O–Si/Al vibration bands in Fourier transform infrared spectroscopy spectra. The improved microstructure resulted in enhancing the compressive strength by 9.01% and 18.18% in optimized bottom ash and slag sand mortars, respectively at the curing age of 120 days. Similarly, the water absorption reduced by 1.03% and 1.24% in bottom ash and slag sand mortars, respectively. [ABSTRACT FROM AUTHOR]

Industrial by-products; have received a lot of attention as a possible precursor for cement and/or concrete production for a more environmentally and economically sound use of raw materials and energy sources. Geopolymer is a potentially useful porous material for OPC binder applications. The use of industrial wastes to produce a greener geopolymer is one area of fascinating research. In this work, geopolymer pastes were developed using alkali liquid as an activator and metakaolin (MK), alumina powder (AP), silica fume (SF), and cement kin dust (CKD) as industrial by-products. Several geopolymer samples have been developed. Research has been carried out on its processing and related physical and mechanical properties through deep microstructure investigation. The samples were cured in water by immersion with relative humidity (95 ± 5%), and at room temperature (~ 19–23 °C) prior to being tested for its workability and durability. The effect of the different composition of precursors on water absorption, density, porosity, and the compressive strength of the prepared geopolymers have been investigated. The results showed that the compressive strength of geopolymers at 28 days of curing is directly proportional to the ratio of the alkali liquid. Ultimately, the best geopolymer paste mixture (GPD1 and GPD2), was confirmed to contain (15% of CKD + 85% MK and Alumina solution (55 wt%)) and (25% of CKD + 75% MK + Alumina solution (55 wt%)) respectively, with 73% desirability for maximum water absorption (~ 44%) and compressive strength (4.9 MPa). [ABSTRACT FROM AUTHOR]

Under the dual-carbon target, CO2 mineralization through solid wastes presents a mutually beneficial approach for permanent carbon emission reduction at a low material cost, while also enabling the resource utilization of these wastes. However, despite its potential, a comprehensive understanding about the effect of industrial solid waste properties and operating parameters on the carbonation process, and the mechanism of direct aqueous carbonation is still lacking. A series of experiments were conducted to compare the carbonation performance of fly ash, steel slag, and carbide slag. Subsequently, CO2 mineralization by carbide slag was systematically studied under various operating parameters due to its high CO2 sequestration capacity. Results showed the reactivity of CaO and Ca(OH)2 was higher than that of CaO·SiO2 and 2CaO·SiO2. Carbide slag demonstrated a sequestration capacity of 610.8 g CO2/kg and carbonation efficiency ζCa of 62.04% under the conditions of 65 °C, 1.5 MPa initial CO2 pressure, 15 mL/g liquid-to-solid ratio, and 200 r/min stirring speed. Moreover, the formation of carbonates was confirmed through XRD, SEM-EDS, TG, and FTIR. A mechanism analysis revealed that initially, the rate of the carbonation process was primarily controlled by the mass transfer of CO2 in the gas–liquid interface. However, the rate-determining step gradually shifted to the mass transfer of Ca2+ in the solid–liquid interface as the reaction time increased. This study lays the foundation for the large-scale implementation of CO2 sequestration through carbide slag carbonation. [ABSTRACT FROM AUTHOR]

The utilization of industrial by-products (IBPs) in cement (OPC)-solidified sludge has been extensively studied as an approach to enhance the mechanical performance, but the presence of salt in groundwater and wetting–drying action would compromise the mass and mechanical behavior of such solidified sludge. Unfortunately, there is a paucity of research on the single or coupled impacts of these two phenomena on IBP–OPC-solidified sludge. This paper aims to address the research gap by exploring the durability of IBP–OPC-solidified sludge in distilled water, sulfate solution and chloride solution through the full immersion tests (IT) and cyclic wetting–drying (WD) tests. Samples were prepared where collected sludge was mixed with OPC and various types of IBPs (including fly ash, slag, calcium carbide residue and silica fume). The resulting unconfined compressive strength, mass loss, and visual changes of samples were evaluated after IT and WD tests. Furthermore, scanning electron microscopy, physisorption experiments, and X-ray diffraction tests were conducted to examine the microstructure, pore evolution and mineralogical characteristics, respectively. Grey correlation model analysis was used to quantify the relationship between components inside IBPs and strength. The results indicate that the use of IBPs is effective in minimizing the mass loss and strength degradation of OPC-solidified samples, with the exception of calcium carbide residue in a sulfate environment. The use of IBPs can promote the formation of C-(A)-S-H gels and increase the amount of hydrated products through pozzolanic reactions and reactions between salt and aluminosilicate phases. Furthermore, the pore volume of solidified samples tends to be reduced, creating a denser matrix with more smaller pores that contribute to excellent mechanical properties and durability. Overall, the findings suggest that IBP–OPC has the potential for promising applications in the high performance of solidified sludge in severe conditions, such as coastal and offshore engineering. [ABSTRACT FROM AUTHOR]

Mushroom production is a growing sector as the demand for this product is increasing. The quantity of waste and by-products generated along the supply chain is however considerable (about 20% of the fresh weight is disposed). Although the recovery of chitosan from mushrooms has been extensively studied, little has been done to optimize the recovery of proteins, which make up to 20% of dry weight. In the present work, six different by-products were studied for their crude composition and their protein fraction was characterized in detail. Then, a comparative study was conducted on three different extraction techniques (environmentally friendly aqueous extraction, ultrasound-assisted extraction, and enzyme-assisted extraction). Enzyme-assisted extraction has proven to be the most efficient technique in terms of protein extraction yield, even though the protein fraction is extracted in the form of peptides and not whole proteins. The lowest degree of hydrolysis is instead given by the ultrasound-assisted extraction, which however shows a rather high degree of racemization which decreases the quality of the proteins. The aqueous extraction, despite the low extraction yield, gave the purest protein extracts. [ABSTRACT FROM AUTHOR]

Globally, the annual generation of industrial and agricultural by-products is exceeding a thousand million tons and forecasted to tremendously inflate in the future. The by-products are usually either landfilled or incinerated causing environmental impacts. Many waste products are effectively utilized in the development of eco-friendly concrete. This study targets the adoption of generated by-products as an alternative to cement in the production of self-compacting concrete (SCC) based on the existing literature. SCC is majorly composed of high cement content, aggregates, chemical admixtures, and water. On the other hand, the cement production emits high levels of carbon dioxide causing environmental hazards and could be reduced to a certain extent by implementing these by-products as cement blends. The by-products are examined for its suitability by the material characterization, physical and chemical properties to match the pozzolanic behavior. This paper reviews comprehensively on the effect of utilizing industrial and agricultural by-products on the workability, strength, permeability, and microstructural performance when blended with SCC. This study summarizes the advantages of utilizing by-products towards the production methodology of a more sustainable and environmentally friendly SCC. [ABSTRACT FROM AUTHOR]

Biodiesel generated by transesterification of triglycerides from renewable sources is a clean form of energy that is currently used in many countries in blends with petrodiesel. It is mainly produced from food-grade vegetable oils obtained from oleaginous crops. High prices of these oils have made the sustainability of biodiesel production questionable. The use of nonedible feedstocks, such as intracellular triglycerides accumulated by oleaginous yeasts, appears as a feasible alternative. However, it has been demonstrated that an economically sustainable production of yeast oil could only be possible if low-cost media based on industrial subproducts, or wastes are used. In this work, we propose intracellular lipids production by a previously selected oleaginous yeast strain in a medium composed only by sugar cane vinasse and crude glycerol. Different culture strategies were studied. The highest biomass and lipid yields were obtained when the yeast R. graminis S1/2R was cultivated in batch without control of dissolved oxygen. The fatty acid methyl esters obtained under these conditions met the specification of international biodiesel standards. [ABSTRACT FROM AUTHOR]

Vegetable by-products represent a valuable source of compounds with biological activity that could be used in food and cosmetics industries. The objective of this work is the valorization through the lipophilic nutraceuticals characterization and in vitro antioxidant activity of Jalapeño pepper industrial by-product oil, and the remainder flour from oil extraction. Jalapeño pepper by-products and whole fruit from two regions: Chihuahua and Sinaloa States from Mexico were obtained from a local industry. From the whole fruit it was prepared a simulated raw by-product, in order to use it to evaluate the effect of industrial scalding process on the by-product. The Jalapeño pepper by-product contain around 22% of oil with important lipophilic nutraceuticals, the oil has a greenness color, and remains attractive concentrations of essential fatty acids, more than 70% of linoleic acid; β-carotene up to 1.85 mg/100 g of oil; α-tocopherol (46.12 mg/100 g of oil) up to four times more than red pepper seeds (C. annuum). Moreover, two and a half and five times more capsaicin and dihydrocapsaicin, respectively, were detected in the oil fraction, than the reported before in no polar extract from whole fruit of C. frutescens. The scalding process reduces the β-carotene, capsaicinoids, and total phenolic content and antioxidant activity of the oil fraction, but despite of this, Jalapeño pepper by-product oil and remainder flour contain bioactive compounds at similar concentrations to previously reports in other peppers. The Jalapeño pepper by-products derived by the food industry have the potential to be used for the recovery of an oil with nutraceutical potential. [ABSTRACT FROM AUTHOR]

In many plants, unsaturated fatty acids are naturally stored in organelles that are named as oil bodies (OB). Wheat germ is a by-product of wheat flour manufacture that is generated in high tonnage globally. Here, an attempt was made to valorize wheat germ through the generation of natural OB emulsions and their extraction was based on an aqueous method. The natural stability limits for OB emulsions were investigated primarily using FT-IR spectroscopy as influenced by processing treatments such as lyophilization, heating and acidification. Differential scanning calorimetry (DSC) and particle size analysis were carried out to complement the FT-IR data. While freeze-drying seemed to have minimal influence on the structural attributes of OB systems, varying pH and extended heating induced destabilization at varying extents. The mean size values for the unprocessed samples were < 8 µm in the first 15 days of refrigerated storage, which was characterized by significant increases in size (d32 ≥ 9 µm) after 15 days. For the reconstituted samples, while the mean size values were < 6 µm in the first 21 days of storage, d32 ≥ 8 µm was observed after 21 days. The location and magnitude of DSC peaks were significantly different between unprocessed vs. lyophilized and reconstituted samples implying processing induced changes in protein structure. At neutral pH, thermal sensitivity of OB emulsions were more pronounced compared to their pH 3 or 9 counterparts. The findings were interpreted primarily in regards to oleosin denaturation and oleosin-oil interactions. Although utilization of hydrocolloids and/or emulsifiers and further homogenization might be necessary to enhance the stability of the current samples, the global capacity in wheat germ generation could justify utilization of wheat germ OB emulsions in food formulations. [ABSTRACT FROM AUTHOR]

In the atmosphere greenhouse gases concentration has rapidly increased due to anthropogenic activities which cause global warming. Portland cement manufacturing process requires enormous amount of energy and also consumes huge quantity of natural resources. To overcome this issue, Portland cement free geopolymer concrete is produced with ground granulated blast furnace slag (GGBS) as main binder and micronized biomass silica (MBS) is substituted in place of GGBS at different quantities. Experimental investigation highlighting mechanical properties and durability performance of geopolymer concrete mixes produced with GGBS and MBS are presented here. Rice husk is used in the manufacture of MBS. Compressive, flexural, split tensile strength, elastic modulus and durability parameters like water absorption, sorptivity, rapid chloride permeability test were conducted. Geopolymer concrete mix with 20 percent MBS and remaining GGBS as binder was found to have optimal strength and durability performance. However, the compressive strength was above the target design strength for all the geopolymer concrete mixes. This experimental investigation vindicates the feasibility of utilizing MBS as a binder raw material in geopolymer concrete production. [ABSTRACT FROM AUTHOR]

Tomato field wastes and industrial by-products represents a valuable source of compounds with nutraceutical potential, and therefore of raw material to obtain food ingredients and additives. The objective of this study was to obtain a flour from tomato industrial by-product and from tomato field waste, dried by a conventional method, that allows to remain important nutraceutical compounds, which in the future, can be used for biotechnological purposes. We found that the drying procedure that allowed to reach an adequate water activity (0.4–0.6) in a forced convection oven were: 55 °C during 120 min. Both, the by-product and the field waste are potential sources for the extraction of phenolic and carotenoid compounds, getting up 11.26 μg/mg dry extract of lycopene and 162.82 μg/mg dry extract of phenolic compounds, highlighting the flavonoids: naringenin, catechin, and rutin. On the other hand, antioxidant analysis showed that oven dried by-product exhibits an inhibition around 80% against hydroxyl and peroxyl radicals, and a positive correlation of both lycopene and β-carotene with myoglobin protection ratio against these radicals. We concluded that the flour from tomato industrial by-products and field waste have nutraceutical properties attractive to the food industry. [ABSTRACT FROM AUTHOR]

Aedes aegypti is the main mosquito vector of dengue, zika, chikungunya, and yellow fever diseases. The low effectiveness of vector control options is mainly related to the increased insect's resistance and to the toxicity of products used for non-target organisms. The development of new environmentally friendly and safer products is imperative. Technical cashew nut shell liquid (tCNSL), mostly composed by cardanol (C), is an abundant by-product of the cashew (Anacardium occidentale L.) production chain, available at low cost, and with proven larvicidal activity. However, chemical modifications in both tCNSL and cardanol were required to increase their water solubilities. Our objectives were to synthesise and characterise sustainable, low-cost and easy-to-use multiple function products based on tCNSL, cardanol, and the sulphonates obtained from both; and to evaluate all these products efficacy as surfactants, larvicidal, and antimicrobial agents. None of the sulphonates presented antimicrobial and larvicidal activities. tCNSL and cardanol were successfully emulsified with sodium technical cashew nut shell liquid sulphonate (NatCNSLS, complex mixture of surfactants). The emulsions obtained presented larvicidal activity due to the presence of tCNSL and cardanol in their composition. Our results showed that the tCNSL+NatCNSLS mixture emulsion was an effective larvicide and surfactant multiple function product, with high availability and easy-to-use, which can facilitate its large-scale use in different environments. [ABSTRACT FROM AUTHOR]

By-products of the grape juice industry contain valuable compounds. The current work produced bioactive-enriched extracts from by-products of the grape juice, through three different extraction methods. Yields and chemical compositions varied, according to the extraction method (ultrasound, microwave, liquid–liquid). High-efficiency liquid chromatography with UV–Vis and high-resolution mass spectrometry characterised were used for chemical characterization, with glycosylated flavonoids evident. The crude extract was fractionated by open column, which has possibility carried-out fraction rich in resveratrol. The inhibition of DPPH radicals ranged from 14.2 to 74.2%, and the total phenolic content ranged from 0.1 to 107.0 mg gallic acid equivalents/100 g. Microwave-assisted extraction of grape juice by-products using polar solvents, such as ethanol and water, provided the best yield and chemical composition, obtaining extracts rich in flavonoids. In this way, this work has demonstrated the industrial grape by-products importances, which are a rich source of antioxidants if properly extracted. [ABSTRACT FROM AUTHOR]

Potential low-cost sorption materials (mostly industrial by-products) were screened for removal of arsenic from mine effluent water. First, the maximum adsorption capacities were determined in batch tests with various liquid to solid ratios. The highest arsenic sorption capacity, 46 mg As/g of sorption material, was measured for cast iron chips. The most promising materials were also studied in batch tests that assessed the reaction kinetics and in kinetic column tests for their behavior in a filter or reactive barrier application. The column tests revealed the cast iron chips caused clogging in the percolation column when operating with real mine water. A commercial ferric oxi-hydroxide sorption material developed for As removal for drinking water showed good As removal in the column tests. Around 10,000 bed volumes of mine process water containing 2 mg/L of arsenic was treated with this material, and treated water concentrations ranged between 0 and 0.05 mg/L before breakthrough. The measured adsorption capacity for the commercial ferric oxi-hydroxide sorption material was 8.3 mg As/g. [ABSTRACT FROM AUTHOR]

This study evaluated the mechanical characteristics and durability of porous concrete produced with a cementless binder based on ground granulated blast furnace slag (BFS), fly ash (FA) and flue gas desulfurization gypsum (CP). As a result, the void ratio was increased slightly from the target void ratio, by 1.12-1.42 %. Through evaluating the compressive strength, it was found that the compressive strength of porous concrete with cementless binder decreased in comparison to the compressive strength of porous concrete with ordinary Portland cement (OPC), but the difference was insignificant, at 0.6-1.4 MPa. Through the freeze-thawing test to evaluate the durability, it was found that the relative dynamic elastic modulus of porous concrete with cementless binder decreased to 60 % or less at 80 cycles. The result of the chemical resistance test showed that the mass reduction rate was 12.3 % at 5 % HCl solution, and 12.7 % at 12.3 and 5 % HSO solutions. [ABSTRACT FROM AUTHOR]

Background: Controlled low strength materials (CLSM), known as flow able fill is used as a replacement of compacted soil in cases where the application of the latter is difficult or impossible. The low mechanical requirements compared with concrete enable the use of industrial wastes for the production of CLSM. In general, CLSM mixtures consist of standard materials such as Portland cement, fly ash, fine aggregate and water. However, other industrial by-products and recycled materials are also accepted and encouraged as long as they are considered to be available, cost-effective for specific application and the necessary characteristics of the mixture such as flowability, strength, excavatability, and density are acceptable. Methods: The aim of this study is to evaluate the feasibility of incorporating red mud as a partial replacement for Portland cement into a controlled low-strength material (CLSM) made by industrial by-products (e.g., ponded ash and fly ash). A control mixture was initially produced with ponded ash, Portland cement, Class F fly ash, and water. For other mix proportions, red mud was substituted for Portland cement in amounts of 5, 10, 15, 20, 25, and 30 % by weight. The bleeding, flowability, fresh density, initial setting time of fresh CLSM mixtures were measured and the follows were hardened ones including compressive strength, corrosivity. Results: Expectedly, all general properties of CLSM incorporating red mud did fall within the acceptable ranges. They performed well and conformed to the requirements of CLSM in ACI 229 standards with regard to flowability, bleeding rate, initial setting time, corrosivity and unconfined compressive strength. Conclusions: The partial replacement of cement by red mud, possibly up to 30 % in mixtures, would reduce flowability and slightly increase corrosivity evidenced by pH but still meet the requirements. Especially, it was found that an increase in red mud content could lead to an improvement in the stability (bleeding rate) and accelerate the setting process on the performances of the proposed CLSM. Finally, with regard to strength at 28 days, CLSM with highest strength could be produced by an optimum replacement of 15 % red mud to cement. In overall, it is worth noting that red mud could be feasible and potential in use as a partial replacement to Portland cement in CLSM production. [ABSTRACT FROM AUTHOR]

This study assesses the impact of variations of the raw mix design, with respect to the type and proportions of materials, on the formation of calcium sulphoaluminate belite ( CSA) type clinkers. Additionally, the hydraulic reactivity, depending on both the raw mix design as well as on the clinker composition, is addressed. Various industrial byproducts and wastes were used to produce raw mixes for different classes of CSA clinkers. The clinkers differed in the ye'elimite over belite ratios: 60/20, 40/40 and 20/60. It was possible to produce all classes of CSA with a relatively comparable mineralogy for a given ye'elimite over belite ratio. The formed clinkers show profoundly different hydration characteristics at early age, depending on the initial raw mix composition. However, after 24 hours, a very comparable hydration development was observed by means of isothermal calorimetry. The hydrates assemblage after 2 days of hydration consists mainly of AFt, X-ray amorphous phases and traces of poorly crystalline phases like aluminium hydroxide and strätlingite. The cement notation is used throughout the document: A = (Al)O, C = CaO, F = (Fe)O, H = HO, K = HO, M = MgO, S = SiO, T = TiO, $$\overline{S}$$ = (SO). [ABSTRACT FROM AUTHOR]

The transformation of byproducts and wastes generated by agro-food companies is of high importance since only a small portion of plant material is utilized directly for human consumption. Squash pumpkin is greatly used in Portugal and as by-products of its processing are generated tons of shell and seeds. In this study we aim to evaluate the potential of these wastes as sources of beneficial and bioactive compounds (antioxidants and antimicrobials), studying the effect of different extraction solvents and drying methods. The samples (fresh and cooked) were freeze-dried and oven-dried followed by extraction with different solvents that revealed the following decreasing order of efficiency: 70 % ethanol, 70 % methanol, 70 % acetone, ultra-pure water and 100 % dichloromethane. The oven-dried samples showed higher values of antioxidant activity and phenolic content, with exception of the values of phenolics for the seeds material. The shell samples presented higher values (1.47 - 70.96 % inhibition) of antioxidant activity and total phenolic content (2.00 - 10.69 mg GAE/g DW). A positive correlation was found between these two parameters on the shell samples, however the squash seeds revealed a negative correlation between the phenolic content and the antioxidant activity. The results show that these industrial agro-food residues are potentially good sources of bioactive compounds with health benefits. [ABSTRACT FROM AUTHOR]

Purpose: Using reactive industrial by-products (IBPs) to reduce phosphorus (P) losses associated with diffuse water pollution is a potentially cost-effective mitigation strategy. However, IBPs must be screened to assess their effectiveness and optimum application rates. This requires accurate estimates of parameters such as the maximum P sorption capacity. Traditionally, these parameters have been derived from the Langmuir model applied to data from batch sorption experiments following a 24-h equilibration period. In this paper, we examined (i) how equilibration time can influence estimates of the maximum P sorption capacity for IBPs and (ii) the relative P sorption characteristics of a range of IBPs available in the UK. Materials and methods: Four IBPs containing different reactive components including ochre, aluminium (Al)-based water treatment residual (WTR), iron (Fe)-based WTR and Fe-lime (CaO)-based WTR were selected for this study. The maximum P sorption capacities of these IBPs were determined using a linearized Langmuir model applied to batch sorption data collected at different equilibration times of 24 h, 5 days and 10 days. Results and discussion: The maximum P sorption capacity of ochre, Al-based WTR, Fe-based WTR and Fe-CaO-based WTR estimated from the linearized Langmuir model following a 24-h equilibration period was 10.1, 13.7, 2.4 and 9.3 mg P g, respectively. However, extending the equilibration time from 24 h to 5 days increased the estimated maximum P sorption capacity for these IBPs by factors of 2.2, 2.1, 6.8 and 2.3, respectively. No significant increase was found in estimates of the maximum P sorption capacity when further extending the equilibration time to 10 days. Conclusions: A minimum equilibration period of 5 days is recommended to avoid underestimating the maximum P sorption capacity of the IBPs examined in this paper. Each of the IBPs we evaluated was able to sorb P from solution, although with variable capacity (maximum sorption capacity after 5 days of equilibration ranged from 16.3-28.5 mg P g). These findings emphasise the importance of accurate quantification of the P sorption capacity of IBPs before application. [ABSTRACT FROM AUTHOR]

Using industrial by-products (IBPs) in conjunction with buffer strips provides a potentially new strategy for enhancing soluble phosphorus (P) removal from agricultural runoff. Here, we investigate the feasibility of this approach by assessing the P sorption properties of IBPs at different solution-IBPs contact time (1-120 min) and solution pH (3, 5.5, 7.5), as well as possible adverse environmental effects including P desorption or heavy metal mobilisation from IBPs. Batch experiments were carried out on two widely available IBPs in the UK that demonstrated high P sorption capacity but different physicochemical characteristics, specifically ochre and Aluminium (Al) based water treatment residuals (Al-WTR). A series of kinetic sorption-desorption experiments alongside kinetic modelling were used to understand the rate and the mechanisms of P removal across a range of reaction times. The results of the kinetic experiments indicated that P was initially sorbed rapidly to both ochre and Al-WTR, followed by a second phase characterised by a slower sorption rate. The excellent fits of kinetic sorption data to a pseudo-second order model for both materials suggested surface chemisorption as the rate-controlling mechanism. Neither ochre nor Al-WTR released substantial quantities of either P or heavy metals into solution, suggesting that they could be applied to buffer strip soils at recommended rates (≤30 g kg soil) without adverse environmental impact. Although the rate of P sorption by freshly-generated Al-WTR applied to buffer strips reduced following air-drying, this would not limit its practical application to buffer strips in the field if adequate contact time with runoff was provided. [ABSTRACT FROM AUTHOR]

In situ metal stabilisation by amendments has been demonstrated as an appealing low-cost remediation strategy for contaminated soil. This study investigated the short-term leaching behaviour and long-term stability of As and Cu in soil amended with coal fly ash and/or green waste compost. Locally abundant inorganic (limestone and bentonite) and carbonaceous (lignite) resources were also studied for comparison. Column leaching experiments revealed that coal fly ash outperformed limestone and bentonite amendments for As stabilisation. It also maintained the As stability under continuous leaching of acidic solution, which was potentially attributed to high-affinity adsorption, co-precipitation, and pozzolanic reaction of coal fly ash. However, Cu leaching in the column experiments could not be mitigated by any of these inorganic amendments, suggesting the need for co-addition of carbonaceous materials that provides strong chelation with oxygen-containing functional groups for Cu stabilisation. Green waste compost suppressed the Cu leaching more effectively than lignite due to the difference in chemical composition and dissolved organic matter. After 9-month soil incubation, coal fly ash was able to minimise the concentrations of As and Cu in the soil solution without the addition of carbonaceous materials. Nevertheless, leachability tests suggested that the provision of green waste compost and lignite augmented the simultaneous reduction of As and Cu leachability in a fairly aggressive leaching environment. These results highlight the importance of assessing stability and remobilisation of sequestered metals under varying environmental conditions for ensuring a plausible and enduring soil stabilisation. [ABSTRACT FROM AUTHOR]

This work outlines an integrated methodology for converting metallurgical by-products into high added value products, through an essentially zero-waste process. Thermodynamic modelling and conceptual design for processing bauxite residues (red mud) from the primary aluminium industry and ferro-nickel production slags are presented as examples. Furthermore, results of semi-industrial scale experiments for processing bauxite residues are illustrated, along with a preliminary financial analysis and an exergy flowsheet of the new conceptual alumina refinery, all confirming the financial viability as well as the resource-efficient utilization of the proposed technology. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to compare the effectiveness of chemical-enhanced soil washing (with chelating agents, humic substances and inorganic acids) and soil stabilisation by inorganic industrial by-products (coal fly ash, acid mine drainage sludge and zero-valent iron) and organic resource (lignite) for timber treatment site remediation. Materials and methods: Both remediation options were assessed in terms of extraction/leaching kinetics and residual leachability (toxicity characteristic leaching procedure, TCLP) of the major risk drivers, i.e. Cu and As. Results and discussion: In chemical-enhanced soil washing, chelating agents only minimised the Cu leachability. Humic substances were ineffective while inorganic acids reduced the As leachability to the detriment of the soil quality. For the waste-stabilised soil, the short-term leaching potential (72 h) and long-term TCLP leachability (9 months) revealed that Fe-/Al-/Ca-rich AMD sludge and coal fly ash sequestered As through adsorption and (co-)precipitation, while carbonaceous lignite stabilised Cu with oxygen-containing functional groups. The short-term and long-term leaching of Cu and As into the soil solution was negligible in the presence of the waste materials. However, the waste-stabilised soil did not maintain sufficient Cu stability in the TCLP tests, in which acetate buffer induced significant mineral dissolution of the waste materials. Conclusions: These results suggest that chelant-enhanced washing (significant reduction of Cu leachability) may be augmented with subsequent stabilisation with inorganic waste materials (effective control of As leachability), thus minimising the environmental risks of both Cu (heavy metal) and As (metalloid) while preserving the reuse value of the soil. Additional tests under field-relevant conditions are required to provide a holistic performance evaluation. [ABSTRACT FROM AUTHOR]