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Engineering Application of Biooxidation Processes for Treating Petroleum-Contaminated Soil
Published in Donald L. Wise, Debra J. Trantolo, Remediation of Hazardous Waste Contaminated Soils, 2018
Chi-Yuan Fan, Anthony N. Tafuri
Soil pH and soil moisture are factors that enter into the selection of microorganisms that will be able to thrive. Consequently, the soil pH will often determine what types of microorganisms can participate in hydrocarbon degradation. Soil pH values ranging from 6 to 8 are required for aerobic activity. The overall rate of hydrocarbon biodegradation is higher under slightly alkaline than under acidic conditions.13 Some soils, particularly those with moderate limestone content, will naturally buffer the pH in the desired range. Peats, soil derived from noncalcareous parent material, or soil exposed to leaching because of high levels of precipitation will tend to be acidic, however, and would have pH levels less than 6. Acidic soils should be amended with calcium carbonate limestone or dolomitic limestone to raise soil pH and provide a source of cations. Some soils, particularly those in arid, desert environments, may be alkaline and have average pH levels above the desired range. Alkaline soils should be amended with acidifying compounds such as aluminum sulfate to lower the pH to the desired range.
Alkali Soils
Published in Ranbir Chhabra, Soil Salinity and Water Quality, 2017
Alkali soils have pH greater than 8.2. Recent studies have shown that there is an intimate relationship between ESP and pH of the saturation paste. As the pH increases, ESP also increases (Fig. 3.10). Since the pH of the saturation paste can be easily determined in the laboratory, this property can be used as an approximate measure of ESP (Table 3.3), which is otherwise a cumbersome determination. The pH of a 1:2 of soil water suspension (pH2) is normally one unit lower than the pH of the saturation paste (pHs) (Fig. 3.11). Though pHs and ESP are well correlated over a large range of ESP, reliable interpretation of the data requires that the pH measurements are thoroughly standardized for any major group of soil.
Soil
Published in Stanley E. Manahan, Environmental Chemistry, 2022
Calcium-deficient soils are relatively uncommon. Application of lime, a process used to treat acid soils (see Section 15.4), provides a more than adequate calcium supply for plants. However, calcium uptake by plants and leaching by carbonic acid (Reaction 15.4) may produce calcium deficiency in soil. Acid soils may still contain an appreciable level of calcium that, because of competition by hydrogen ion, is not available to plants. Treatment of acid soil to restore the pH to near neutrality generally remedies the calcium deficiency. In alkaline soils, the presence of high levels of sodium, magnesium, and potassium sometimes produces calcium deficiency because these ions compete with calcium for availability to plants.
Impact of greywater on germination and physiological responses of Triticum aestivum L. HD 2967 in soil amended with poultry biochar
Published in Environmental Technology, 2023
Rekha Kumari, Rozi Sharma, Neeraj Kumar Sharma, Deepak Pant, Piyush Malaviya
The soil used in the study was alkaline, this alkalinity along with nutrients decreased with time, and the decline was prominent for 50% GW irrigation. Accordingly, greater nutrients were found in soil with 100 per cent GW irrigation particularly, for soil and 10 g biochar amendments. The pH between 6 and 7.5 is considered optimum for plant and soil microorganisms, care is needed when soil pH is more than 8.2 or drops below 6. As GW irrigation resulted in higher EC and soil pH; therefore, regular monitoring of GW irrigated soil is necessary and if soil pH is above 7.5 it needs to be neutralized by the addition of gypsum. Increasing the pH of alkaline soil may have an impact on nutrient solubility and bioavailability [24]. It causes an accumulation of salts [24], which can be prevented by repeatedly backwashing with freshwater which leads to the dilution of salt content. The data revealed that fewer variations were observed on the 14th day after sowing as compared to the initial day. Greywater has proven to be a useful substitute for freshwater, especially in non-potable uses such as toilet flushing and irrigation.
Effect of biochar, iron sulfate and poultry manure application on the phytotoxicity of a former tin mine
Published in International Journal of Phytoremediation, 2021
Manhattan Lebrun, Florie Miard, Romain Nandillon, Domenico Morabito, Sylvain Bourgerie
Overall, biochar and poultry manure addition had no effect on Phaseolus vulgaris growth; only iron sulfate application improved plant growth. In general, the biochar amendment increased plant growth (Lebrun et al.2017; Trakal et al.2017) due to the improvement of soil conditions. However, similarly to this study, previous studies did not observe an increase in plant growth following biochar amendments (Jones et al.2012; Lebrun, Miard, Hattab-Hambli, et al.2018; Chan et al.2007; Cui et al.2012; De Tender et al.2016) and linked this result it to the absence of biochar effect on the soil parameters, and low application rate (Lomaglio et al.2018). Indeed, in this study, biochar had no effect on the pH or metal(loid) concentrations in SPW. Manure is also known to increase plant DW biomass due to its high nutrient content (Marques et al.2008; Walker and Bernal 2008). Moreover, in general, a neutral to sub-alkaline soil pH is a factor leading to plant growth amelioration whereas an acidic pH is often detrimental for plant growth (Carter et al.2013). However, the optimum pH range for growth will depend on the plant species. Here, an increase in plant growth was only observed with the iron sulfate amendment, which showed a decrease in SPW pH. Therefore, the plant growth results indicate that the lower growth observed on non-amended Abbaretz substrate was mainly related to higher As SPW concentrations (Namgay et al.2010), and not to nutrient deficiency, as poultry manure had no effect.
Heavy metal contamination and ecological-health risk evaluation in peri-urban wastewater-irrigated soils of Beni-Mellal city (Morocco)
Published in International Journal of Environmental Health Research, 2020
Ahmed Barakat, Widad Ennaji, Samira Krimissa, Mustapha Bouzaid
The acidity or alkalinity in soils controls the heavy metal mobility. Generally, the mobility of metals in alkaline soils decreases. The measured pH showed values varying between 7.2 and 7.8, with an average of 7.7, suggesting thus that the studied soil samples are alkaline. This alkalinity of the studied soil could be related to the local geology that is carbonated. The alkaline soil nature favorites the heavy metal retention and reduces their mobility in the soils (Tian et al. 2017).