Recent development in the treatment of oily sludge from petroleum industry: A review

Fly ash-based geopolymer: clean production, properties and applications

Immobilisation of heavy metal in cement-based solidification/stabilisation: a review.

Geopolymers for immobilization of Cr6+, Cd2+, and Pb2+

Leaching behavior of heavy metals from municipal solid wastes incineration (MSWI) fly ash used in concrete.

Factors affecting hazardous waste solidification/stabilization: a review.

An attempt was made to judge the environmental compatibility, the governing leaching mechanism, and mobility patterns in a waste–cement solidified/stabilized matrix after 21 days of curing. The mixed sludge from a steel pickling facility was stabilized by ordinary Portland cement. Iron was the major leachable metal, along with Pb, Zn, and Mn. To characterize the leaching behavior, the mobility and mechanism of leaching were determined by diffusion leaching tests. In the solidified/stabilized matrix, the mobility of all the elements studied was reduced, and average to low mobility was observed. Values for the negative log of the effective diffusion coefficient of more than 12.5 were obtained for the metals. The dominant leaching mechanisms were surface wash off in the initial stage, followed by diffusion. The environmental performance of the solidified/stabilized product when considered in terms of mass leached over 64 days was found to be satisfactory for consideration for the safe disposal and reuse of waste.

Evaluation of leaching characteristics and environmental compatibility of solidified/stabilized industrial waste

The sludge from a steel processing unit bearing zinc, lead, iron, and manganese was solidified with ordinary Portland cement. The waste was stabilized in the specimens with a waste/binder ratio range of 0.16–4.0. On the basis of the available leaching and unconfined compressive strength, the performance of the solidified/stabilized waste was compared for different numbers of curing days. It was found that curing up to 28 days resulted in a performance improvement, as shown by less leaching of heavy metals and the increased unconfined compressive strength of the specimen. The treatment effectiveness of the solidification/stabilization process was assessed for the metals Pb, Zn, Fe, and Mn, and was found to be 89%, 95%, 74%, and 90%, respectively, for an optimum ratio of 4.0 after 28 days of curing.

Study of the treatment effectiveness of a solidification/stabilization process for waste bearing heavy metals

In this paper, an effort has been made to understand the factors, which affect fixation of heavy metals in solidified/stabilized matrix. Various aspects related to the solidification/stabilization of different heavy metals (Ar, Ba, Cu, Cr, Pb, Zn, Hg) are reviewed. A comparative study of different binders for the fixation of each metal has also been carried out to suggest the most suitable binder, pretreatment required for the metal. Valence, speciation, pH and other factors are also considered while reviewing metal retention capacity of different matrix.

Factors affecting fixation of heavy metals in solidified/stabilized matrix: a review.

Disposal of industrial effluents containing synthetic dyes causes a potential hazard to the land and environment and therefore dyes need to be removed before disposal. In the present study, combined effluent treatment plant (CETP) sludge was activated at 200° C for 1 hour and used as an adsorbent for the removal of malachite green dye from wastewater. The adsorbent was characterized by XRF, SEM, XRD and FTIR. Batch studies were carried out under various experimental conditions by varying contact time, dye concentration, adsorption dose, pH and temperature to assess the potentiality of activated sludge for the removal of malachite green dye from wastewater. The results revealed that the removal of malachite green dye was strongly pH dependent and maximum dye removal was observed at equilibrium pH of 8.0. Optimum adsorbent dose and contact time were found to be 10 g/l and 180 minutes respectively. Thermodynamic studies showed the spontaneous and endothermic nature of the adsorption. Adsorption data have also been correlated with different isotherm models. Hence activated sludge can be used as an effective adsorbent for the removal of malachite green dye from wastewater. It could be considered as good replacement of commercially available adsorbent like zeolites, activated carbon etc. due to its significant low cost and high sorption efficiency.

Rachana Malviya

Papers

Factors affecting hazardous waste solidification/stabilization: a review.

Evaluation of leaching characteristics and environmental compatibility of solidified/stabilized industrial waste

Study of the treatment effectiveness of a solidification/stabilization process for waste bearing heavy metals

Factors affecting fixation of heavy metals in solidified/stabilized matrix: a review.

Equilibrium, Kinetic and Thermodynamic Studies of Malachite Green Dye Removal using Activated Sludge from Common Effluent Treatment Plant