The influence of treated oleo-chemical wastewater applications on the metal speciation forms in soils

Abstract

This paper presents a developed method of pretreating wastewaters coming from small-tonnage oleochemical production and also the research results on the variability of concentrations of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn) in the soil irrigated and fertilized with wastewater from this production. The processing wastewater pretreatment was carried out at two stages. The first stage eliminated fatty substances by using dispersed air flotation aided with hydrogen peroxide as an oxidizer. The second stage included coagulation and chemical precipitation with milk of lime, flocculation, final dissolved air flotation (DAF), and also oxidation with hydrogen peroxide. Field experiments, the aim of which was to compare variability levels for speciation fractions of heavy metals, were carried out according to Tessier's method for four years. The study revealed that the average concentrations of the given metals fractions in soil samples where raw wastewaters were directed did not significantly change during the experiment, which clearly justifies the need for their physicalÁchemical pretreatment and further agro-utilization without the risk of soil environment degradation. The successive decrease of exchangeable fraction, the increase in the content of the fraction bound with carbonate forms, and stability of the fraction bound with hydrated iron and manganese oxides as well as organic and residual fractions were found in soil samples treated with pretreated wastewaters.

Formulation of Plant Nutrient with Synbiotic Enhancement

“…Nevertheless, oleo-chemical plants deal with manufacturing fatty products such as vegetables and animals, and the oleochemical sludge waste in this research comes from FPG Oleochemicals Sdn Bhd, which manufactures fatty alcohols, methyl esters, glycerine, and other organic chemicals mainly from palm plantation. Wastewaters from production contain fats, which after pre-treatment could be used in plant farming as fertilizers because they are biodegradable [3]. Due to the presence of nutrients such as nitrogen (N), phosphorus (P), and potassium (K), it is possible to optimize and regulate N:P:K in the mixed wastewaters for plant nutrients [3].…”

“…Wastewaters from production contain fats, which after pre-treatment could be used in plant farming as fertilizers because they are biodegradable [3]. Due to the presence of nutrients such as nitrogen (N), phosphorus (P), and potassium (K), it is possible to optimize and regulate N:P:K in the mixed wastewaters for plant nutrients [3].…”

Removal of Cadmium From Contaminated Soil Using Iron (Iii) Oxide Nanoparticles Stabilized With Polyacrylic Acid

“…Selective sequential extraction (SSE) is widely used for this purpose (Tessier et al 1979;Huang et al 2012Huang et al , 2016. Selective sequential extraction methods have been used for assessment of several heavy metals removal from soils, sediments, compost, sludge and wastewater and also the mobility of these metals have also been studied (Mulligan, Dahrazma 2003;Dahrazma, Mulligan 2006;Hseu 2006;Fan et al 2012;Zaleckas et al 2013;Zak et al 2013;Uduma, Jimoh 2013;Ozbas, Balkaya 2014;Zhao et al 2014;Pandey et al 2015).…”