The Applicability of Electrical Current Based Treatment for the Remediation of Different Types of Polluted Soils Contaminated by Organic Compounds

Abstract

This study focused on the effect of the variation of intermediate volatile fatty acids (VFAs) caused by the change of organic load on methane production and methanogenic community shift during anaerobic digestion (AD). Eight groups with different F/I (VS food wastes :VS sludge ) were conducted, while the inoculation sludge had a same amount. Operational performance for every groups was monitored by assessing biological activity, methane production, concentration of VFAs. The major intermediate VFAs of anaerobic digestion were acetate, propionate, iso-butyrate, n-butyrate, n-valerate and iso-valerate; and acetate and n-butyrate were the most abundant components. The increasing of F/I changed the predominant VFAs type from acetic acid to n-butyric acid, while the total VFAs concentration increased. Besides, the methane production increased and then decreased, and reached the maximum (170.3 ml/g added VS -1 ) at F/I of 1. The methanogenic diversity was screened using the high-throughput sequencing, which shown VFAs had a significant impact on the archaeal community as the dominant archaea shifted from Methano bacterium to Methano sarcina.

Enhanced ex-situ bioremediation of soil contaminated with petroleum refinery waste effluents by biostimulation through electrokinetics and inorganic fertilizer

“…Furthermore, these observations revealed that irrespective of the applied specific voltage, pH relatively increased with increased distance from anode (conversely, pH decreased with increase of distance from cathode). Similar observations have been reported [12,30,35].It was generally observed that the moisture content decreased with time at the different applied voltage and hence sterilized distilled water was added at intervals so as maintain the moisture content at 30%.…”

“…Similar observations have been reported [12,21,35]. Nevertheless, the pH across soil bed was generally maintained between 6.8 and 7.5 which were still favourable for the autochthonous microbial activity; this was possible due to regular reversal of current intensity [12,35].…”

“…Similar observations have been reported [12,21,35]. Nevertheless, the pH across soil bed was generally maintained between 6.8 and 7.5 which were still favourable for the autochthonous microbial activity; this was possible due to regular reversal of current intensity [12,35]. It was generally observed that the moisture content decreased with time at the different applied voltage and hence sterilized distilled water was added at intervals so as to maintain the moisture content at 30%.…”

Remediation of Soil Polluted by Organic Compounds Through Chemical Oxidation and Phytoremediation Combined with DCT

“…In recent years, electrochemical applications used to reduce pollution have received increasing attention [45,46,47,48]. In such applications, the removal of pollutant species takes place directly or indirectly through electrochemical oxidation or a reduction process in the electrochemical cell, without the continuous supply of chemical additives.…”

“…In such applications, the removal of pollutant species takes place directly or indirectly through electrochemical oxidation or a reduction process in the electrochemical cell, without the continuous supply of chemical additives. The selectivity of many electrochemical processes also helps to prevent the production of derivatives and/or waste, which in many cases should be properly treated before disposal [47,48]. Despite these advantages, there are limitations to such applications, for example the heterogeneous nature of the electrochemical processes, as well as the long-term stability and activity of the electrode material and cell components.…”