Extractable Al and Mn were reduced by the addition of fly ash and Calmasil to levels comparable to lime in the incubated soils. The addition of fly ash and Calmasil also increased the extractable base cations of both soils. The use of fly ash and Calmasil in lower quantities has great agronomic potential in improving soil acidity.
The effect of fly ash and processed stainless steel slag on soil pH, EC, extractable Al, Mn, base cations and trace elements 40. The effect of liming with fly ash and processed stainless steel slag: a preliminary study in the greenhouse with perennial ryegrass 59 Figure (i) A flowchart of the focus, objectives and some of the methods used in this preliminary study on the liming effect of fly ash and processed stainless steel.
List of Tables
List of Appendices
- Correlation matrices for trace elements leachable with TCLP, SPLP, and ART estimated correlation coefficients using Persons two-tailed
- Extractable trace elements of the incubated Avalon soil treated at rates of 0, 100 and 400% of the optimum liming rate (OLR) with equivalent
- Extractable trace elements of the incubated Inanda soil treated at 0, 100 and 400% of the optimum liming rate (OLR) with equivalent rates of fly
- ANOVA tables for the yield of perennial rye grass grown on the Avalon and Inanda soils treated at rates of 0, 50, 100, 200 and 400% of the
The present research is a preliminary evaluation of the suitability of fly ash from the Duvha power plant and a processed stainless steel slag, Calmasil, commercially distributed by Calmasil Pvt. The research aims to evaluate the potential benefits of applying fly ash and processed stainless steel slag to acidic agricultural soils in an effort to improve soil quality with minimal negative impacts on the environment, while also providing an alternative disposal option. A review of the literature on soil acidity and possible strategies for amelioration using fly ash and processed steel slag is given in the next chapter.
A flowchart of the focus, objectives and some methods used in this study on the liming effect of fly ash and processed stainless steel slag on acid agricultural soils. Effect of liming two acidic soils with fly ash and stainless steel slag on plant growth. Soil acidity and its possible strategies for improvement using fly ash and processed stainless steel slag.
Soil acidity and the potential strategies for amelioration using fly ash and processed stainless steel slag
- Introduction
- Soil acidity and its amelioration
- Fly ash
- Processed stainless steel slag
- Legal implications of liming acid agricultural soils with fly ash and processed stainless steel slag
- General conclusions
Some fly ash materials are pozzolanic, exhibiting cementitious properties when exposed to water and an activator (Adriano et al., 1980; Daniels et al., 2002). Increases in the pH of acidic soils treated with fly ash have been reported in pot experiments by Khan and Khan (1996), Sale et al. The increase in pH of the treated soils can be attributed to the alkaline nature of some fly ash and the absorption of H during the dissolution of non-alkaline compounds (Adriano et al., 1980;.
Under field conditions, Adriano et al. 2002) reported similar findings in the tilled layer (0-15 cm) of acid soils treated with fly ash in the first year of a three-year experiment. However, fly ash at relatively low doses is not expected to negatively affect the physical properties of soil (El-Mogazi et al., 1988). Processed stainless steel slag has pozzolanic properties (Shen et al., 2004), exhibiting cementitious properties when exposed to water and an activator.
Characterisation of fly ash and processed stainless steel slag
- Introduction
- Materials and methods
- Results and discussion
- Conclusions
The quality of fly ash and Calmasil as lime materials was determined using the procedures of McFarland et al. Comparison of some heavy metals present in fly ash and Calmasil (extracted with aqua regia) to the limits for heavy metals in wastewater of DWAF (2006) and EPA Part 503 Biosolids Rule (40 CFR Part 503) (USEPA, 1994) was performed. The differences in the morphology of the fly ash particles used in this study are consistent with results reported by Foner et al.
The low CCE or NV of fly ash compared to Calmasil and lime indicates that its calcification potential is low (Tables 2.3 and 2.4). In general, the levels of extractable plant nutrients in fly ash and Calmasil were higher than lime. In general, the concentrations of trace elements in the TCLP extracts of fly ash, Calmasil and lime were lower than the TCLP limits with the exception of As and Se in fly ash (Table 2.6).
The SPLP leachate levels of Mo in fly ash and Calmasil are high but are lower compared to lime. In general, the levels of trace elements in fly ash ART leachates, Calmasil and lime are low with the exception of As, V and Mo in fly ash (Table 2.8). The levels of most of the trace elements in the fly ash ART leachate are similar to the TCLP leachate (Table 2.6).
The high levels of As, Mo and Se in the fly ash leachates used in this study are consistent with Jankowski et al. In general, the concentrations of trace elements in the SPLP fly ash leachate were lower than the TCLP and ART leachate. Some of the physical and chemical properties of the fly ash and processed stainless steel slag used in this investigation are comparable to lime.
Fly ash is a potentially hazardous material due to high levels of As and Se.
The effect of fly ash and processed stainless steel slag on soil pH, EC, extractable Al, Mn, base cations and trace elements
- Introduction
- Materials and methods
- Results and discussion
- Conclusions
Fly ash treatments in Avalon soil at the two highest rates of 200% and 400% OLR showed an increase to the desired extent for perennial ryegrass growth. Treatments with Calmasil in Avalon soil showed an increase in soil pH to the desired range by three levels and 400% OLR (Figure 3.1). The pH reduction shown by Calmasil treatments at these rates is comparable to similar fly ash treatments (Figure 3.1).
The pH value of Inanda soil treated with fly ash, Calmasil and lime increased as application rate increased and with time (Figure 3.2). Fly ash treatments in Inanda soil showed an increase in soil pH to a desired pH between 5 and 8 only at the highest application rate of 400% OLR (Figure 3.2). The lower than expected increase in pH with the fly ash treatment in both soils appears to be contrary to the expected results as the CCE at different rates was the same as the other materials.
Extractable Al in the fly ash, Calmasil and lime treatments in Avalon soil and Inanda soil showed a decrease with increasing application rate and time (Figures 3.3 and 3.4). Extractable Al at the two highest application rates 100% and 400% OLR in the fly ash, Calmasil and Inanda soil lime treatments were significantly lower than the zero rate (Figure 3.4). Extractable Mn levels decreased with increasing application rate and time in the fly ash, Calmasil and lime treatments in the Avalon and Inanda soils (Figures 3.5 and 3.6).
The extractable Mn was not readily extractable in any of the higher treatments in the Avalon soil. The 1M NH4NO3 and 0.01M CaCl2 extractable trace elements in the treatments with fly ash, Calmasil and lime from both soils showed a trend similar to the DTPA extractions (Appendix 3.1 and 3.2). The Ni in the treatments with Calmasil from both soils showed a similar trend to As in the fly ash treatments.
The overall decrease observed in the fly ash treatments is consistent with the results reported by Bilski et al.
The effect of liming with fly ash and processed stainless steel slag on plant growth: a preliminary glasshouse investigation with perennial
- Introduction
- Materials and Methods
- Results and Discussion
- Conclusions
- General conclusions and recommendations
The yield of ryegrass in the treatments with lime showed a trend different from the yield with fly ash and Calmasil, with the highest yield at the lowest application rate of 50% OLR followed by a decrease to a constant yield for the following three higher application rates. The yield of ryegrass grown on the treated Inanda soil was generally in the following order: fly ash > Calmasil > lime (Figure 4.4). The yield of ryegrass grown on the Inanda soil treated with fly ash showed an increase as the application rate increased and reached a maximum at the highest application rate (Figure 4.4).
The yield response of ryegrass grown on Inanda treated with fly ash and Calmasil showed a different trend than the Avalon soil. The overall increase in ryegrass yield with increasing application rates of ash and Calmasil at higher rates than lime suggests that the yield increase was not solely the result of improved soil acidity. Improved plant growth in the fly ash and Calmasil treatments of both soils was probably due to increased plant nutrient supply as they have a higher nutritional value (Chapter 2).
The high concentrations of Si in fly ash and Calmasil (Figure 2.4) may therefore also have played a role in improving the growth of ryegrass in the treated acid soils. The soil type greatly influences the growth response of ryegrass grown in acidic soils amended with fly ash and Calmasil. However, the growth response of perennial ryegrass to fly ash and Calmasil is not necessarily an indication of a low toxicity threat.
Fly ash increased Avalon and Inanda soil pH with increasing application rate. Fly ash and Calmasil improved the growth of perennial ryegrass at the optimum lime rate and higher at greater lime rates in both soils. Application of fly ash and Calmasil at higher rates in Avalon with low organic carbon and clay may pose a phytotoxic threat.
The investigation showed that liming the Avalon and Inanda soil with fly ash and Calmasil improved the growth of perennial ryegrass.
Review of the physico-chemical and biological properties of fly ash and effects on agricultural ecosystems. Differential effects of weathered coal fly ash and filter ash leachate on maize genome. Effect of coal fly ash application on the mobility and distribution of trace elements in soil, plants and leachate.
Application of fly ash to two acidic soils and its effect on soil salinity, Ph, B, P and on the growth and composition of ryegrass. Fly ash - a potential source of soil improvement and part of an integrated plant and nutrient supply system. Effect of soil application of fly ash on the chemical composition and yield of maize (zea mays L.) and on the chemical composition of displaced soil solutions.
Effect of fly ash, organic waste and chemical fertilizers on yield, nutrient uptake, heavy metal content and residual fertility in a rice-mustard cropping sequence under acid lateritic soils. Barley seedling growth in soils amended with fly ash or agricultural lime followed by acidification. The production of artificial soil from sewage sludge and fly ash and the subsequent evaluation of growth enhancement, heavy metal translocation and leaching potential.
Effect of fly ash on the availability of Zn, Cu, Ni and Cd for chicory. Comparison of technical and durability properties of fly ash mixed cement concrete made in the UK and Malaysia. Efficacy of various amendments to improve fly ash toxicity: growth performance and metal composition of Cassia siamea Lamk.
Suitability and effectiveness of power plant fly ash for coal water quality control.
Appendices
Correlation matrix for TCLP, SPLP, and ART estimated correlation coefficients using Persons two-tailed test for fly ash, Calmasil and
