Bioremediation <i>In Situ</i> of an Alkaline Soil Polluted with Heavy Metals

Abstract

An experimental plot consisting of alkaline soil heavily polluted with heavy metals (copper, zinc, cadmium) was treated in situ by stimulating the activity of the indigenous soil microflora, which contained different metal-solubilizing microorganisms. This was achieved by adding to the soil solid biodegradable organic substrates (cow manure, plant compost, straw), zeolite saturated with ammonium phosphate and aqueous solution containing acetate, lactate and magnesium chloride. An efficient removal of the above-mentioned heavy metals was achieved via the drainage water and their residual contents in the soil decreased to below the relevant permissible levels within 18 months of treatment. The metals were solubilized mainly as complexes with the organic acids added by the irrigating water solutions or secreted by the indigenous heterotrophic microorganisms. The effluents containing dissolved metals were efficiently treated by means of a wetland constructed near to the experimental plot.

The Feasibility of Energy Extraction from Acidic Wastewater by Capacitive Mixing with a Molecular‐Sieving Carbon Electrode

“…Acidic wastewater can originate from various industries, such as electroplating, leaching, metal finishing, and phosphate production [1,2] Safe disposal of acidic wastewater poses major environmental challenges. Most of the acidic wastewater also containsh eavy metals; however, these can be extracted by methods such as supplied or chelating precipitation, ion exchange, electrochemical treatment, adsorption,a nd membrane filtration [3][4][5][6][7] After removalo ft he hazardous heavy metals, the acidic wastewater disposal itself is still of great concern for the environment and ecological systems.…”

Soil Contamination by Heavy Metals and Radionuclides and Related Bioremediation Techniques: A Review

“…The soil rehabilitation process of microbes is carried out using mechanisms such as bioprecipitation, biosorption, bioaccumulation, bio-assimilation, bio-extraction, biodegradation, and biotransformation [58][59][60][61][62][63]. Some methods for fixing heavy metals and radionuclides are shown in Figure 4.…”

“…This activity was intensified by the corresponding changes in environmental factors, such as water, oxygen, and nutrient levels. Furthermore, dissolved-impurities soil leachates were efficiently treated using a nearby natural wetland ecosystem [59].…”

“…Physical and chemical methods can precede biological methods and serve as a preliminary stage. Groudeva et al [59] investigated the dissolution and removal of contaminants from soil using Na 2 CO 3 and NaHCO 3 solutions, linked to the activity of heterotrophic and basophilic chemo-lithotrophic microorganisms. This activity was intensified by the corresponding changes in environmental factors, such as water, oxygen, and nutrient levels.…”