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Showing 2 results for Water Treatment Plant Sludg
Adsorption of Reactive Red 198 Azo Dye fromAqueous Solution onto theWaste Coagulation Sludge of theWater Treatment Plants
H. Asilian, G.r Moussavi, M. Mahmoudi,
Volume 3, Issue 1 (4-2010)
Abstract

Backgrounds and Objectives:Much attention has been recently paid on using waste materials as adsorbents for removal of contaminants from water and wastewater. A new low cost waste was examined for its capacity to adsorb RR198, an azo reactive model dye, from an aqueous solution.
Materials andMethods: The waste was dried, powdered and characterized before being used as an adsorbent. The effects of pH (3-10), adsorbent dose (0.2-3 g), dye concentration and contact time on the adsorption efficiency were investigated. Equilibrium study data were modeled using Langmuir and Freundlich models.
Results: The characterization analysis indicated that itwas composedmainly of ferric hydroxide. The powder had a BET and average pore size of 107 m2/g and 4.5 nm, respectively. The results showed that dye removal was highest at a solution pH of 7 to 8 and a powder dose of 2 g/L. The RR198 removal percentage decreased from 100& to 43& at 140 min contact time when the concentration of dye was increased from 25 mg/L to 100 mg/L, at optimum pH and dosage. The Langmuir equation provided the best fit for the experimental data. The maximum adsorption capacity was calculated to be 34.4 mg/g.
Conclusion: According to the obtained results, the water coagulation waste sludge appears to be a suitable low cost and effcient adsorbent for removing reactive azo dyes from waste streams.


Risk assessment of exposure to heavy metals (Pb, Cd, Cr, and Ni) in the hazardous solid wastes identified in the wastewater treatment plant of industrial city
Hamid Kariab, Mohammad Mehdi Emamjomeh, Sheida Zakariaie,
Volume 15, Issue 4 (3-2023)
Abstract
Background and Objective: Due to the presence of heavy metals (HMs), sludge produced in industrial wastewater treatment plants (WWPT) is classified as special waste and can cause adverse health effects. The present study aimed to identify special wastes and assess the risk associated with the presence of HMs in the sludge of WWTP from an Industrial City.
Materials and Methods: Identifying the special wastes was conducted using a checklist, and classification was performed in accordance with the Basel Convention. Ecological risk assessment was done by determining the geo-accumulation and ecological indexes. The estimation of health risk was done by determining HQ and ELCR indexes.
Results: The highest amount of special waste was allocated to sludge with a value of 3900.0 kg/month. Chromium was detected in the highest concentration (95.89 ± 52.15 mg/kg). The level of chromium and nickel pollution was evaluated in the low range, and cadmium was very severe. The ecological risk of lead was estimated in a significant range and was very high for cadmium. The HQ was less than 1, and the ELCR for inhalation and dermal exposure was estimated to be lower than the acceptable risk level of WHO.
Conclusion: The present study showed that the largest amount of special waste is dedicated to sludge. Although the concentration of  HMs was lower than the acceptable limits, the sludge had a high ecological risk level. Therefore, the accumulation and transfer of sludge must be carried out under the provisions of the Basel Convention and environmental considerations.

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