Application of Bioremediation on Solid Waste Management: A Review

Abstract

IntroductionAquatic ecosystems are mainly affected by heavy metals and represent a potential risk to the health of humans and ecosystems [1]. Heavy metal ions in the environment are biomagnified in the food chain and are accumulated in tissues. Although low concentrations of some heavy metals are metabolically important to many living organisms, at higher levels they can potentially be toxic [2].Arsenic (As) is a component of many industrial raw materials, products and wastes. Elevated levels of arsenic in drinking water have been implicated in human diseases and mortality [3]. Chronic exposure to arsenic causes neurological and haematological toxicity [4]. Arsenic impacts the major organs and is a potential carcinogen [5][6][7]. The most common arsenic species observed in the environment are the trivalent form arsenite As (III) and pentavalent form arsenate As (V) in which As (III) is more toxic than As (V) [8]. Because arsenic readily changes valence state and reacts to form species with varying toxicity and mobility, effective treatment of arsenic can be challenging. Arsenic treatment technologies require peroxidation step to form As (V) from As (III) [9] but the cost and secondary product formation during other conventional methods reduce the practices [10]. Use of biological processes provides a means for cost-effective removal of metals for the treatment of metal contaminated waters.Microbes are ideal candidates to decrease the heavy metal ion concentration from ppm to ppb levels [11]. Microalgae are known to sequestrate heavy metals due to their cell wall constituents which act as binding sites for metals [12][13][14][15][16][17]. Bioaccumulation of metals by algae may create a feasible method for remediating water contaminated with metals [18,19]. It is well established that several marine and fresh water algae are able to take up various heavy metals selectively from aqueous media and to accumulate these metals within their cells [20][21][22]. Microalgae have been shown to accumulate arsenic and could potentially remediate through adsorption and biotransformation of inorganic arsenic [23][24][25].In this study, the emphasis has been laid to know the efficiency of fresh water algal species in removing the arsenic from aqueous solutions. The research was to simultaneously determine the differences in arsenate and arsenite sorption capacities of living and dried algal biomass. Materials and Methods Sample collection and identificationAlgal samples were collected from Bangalore fresh water habitats (13°04'N, 77°58'E) and washed several times with tap water and then with deionized water before analysed by using microscope. The family and genus identified with reference to the biology of algae [26]. The identified algae were Chlorophyceae (Botryococcus, Chlamydomonas, Chlorella, Gonium, Pandorina, Scenedesmus, Spirogyra, Volvox), Cyanophyceae (Oscillatoria, Spirulina) and Euglenophyceae (Phacus). ChemicalsAll chemicals used in this study were of analytical reagent grade. Stock solutions of 100 mg/L concentra...

Microbe-mediated bioremediation: Current research and future challenges

“…It has been estimated that about 1000 new chemicals are synthesized annually. More than 450 million kilograms of toxins are released globally into air and water in accordance to the third world network reports [1]. The pulp and paper industry is known to be the sixth largest polluter of the environment [2].…”