Effect of humic compost on the adsorption of cadmium (II) in aqueous medium.

The humic compost obtained from the treatment of tobacco from smuggled cigarettes (SCT) and industrial sewage sludge (ISS) was evaluated as adsorbent for Cd (II) in aqueous solution, for possible decontamination of water resources. Optimum conditions were found at pH 5 and a 3 g/L adsorbent concentration, which presented 92% Cd (II) removal and maximum adsorption capacity of 28.546 mg/g. The pseudo-second-order kinetic model presented the best fit, pointing 120 min as the time needed to attain a steady state. FTIR and EDX results suggest the formation of coordinated Cd (II) bonds by functional groups between the compost and the solution. The results obtained in real samples showed that, even under different environmental conditions, the Cd (II) adsorption varied between 80.05 and 91.61%. The results indicated that the compost evaluated can be used for remediation of Cd (II)-contaminated water resources.

Combined process of chemically enhanced sedimentation and rapid filtration for urban wastewater treatment for potable reuse.

The objective of this study is to propose a new post-treatment of effluents from Upflow Anaerobic Sludge Blanket (UASB) using rapid filtration, aiming at the production of water for potable reuse. The final quality of the effluent produced by the treatment using gravel, sand, clinoptilolite and activated carbon associated with disinfection was evaluated by physical chemical analysis, heavy metals and persistent organic contaminants. Experiments were carried out in jar test, filter operation time, evaluation of the efficiency using peracetic acid and free chlorine as disinfectant and all results were statistically analysed. The best conditions were those using 20 mg/L of ferric chloride and natural pH of the effluent (≈ 7.0), which resulted in less reagent consumption. The use of intermediate fund discharges made it possible to obtain approximately 91% of recovered water efficiency. The effluent treated under these conditions showed DOC <2.0 mg/L, COD <1.0 mg/L, BOD <1.0 mg/L, turbidity <1.0 NTU, TSS <1.0 mg/L, ammonia <0.1 mg/L, total phosphorus <0.1 mg/L and surfactants <0.1 mg/L. The disinfection process with free chlorine and PAA allowed the total inactivation of faecal coliforms and total coliforms. The treatment using rapid filtration with disinfection by chlorine reached the appropriate level for urban, environmental, industrial and indirect potable water reuse.

Treatment of smuggled cigarette tobacco by composting process in facultative reactors.

This paper presents a study on the degradation of smuggled cigarette tobacco combined with domestic organic waste and sawdust or wood chips, using facultative reactor. Four reactors with different amounts of residue were assembled. For the study of the quality of the compost obtained, physicochemical, phytotoxicity and microbiological analyses were carried out. The mixture with wood chips presented the best temperature conditions and pH variation optimizing the degradation. The final germination index (GI) values of all treatments were above the recommended GI value (50%) and the final C/N ratio between 8 and 13 indicated a mature compost. The concentration of metals under study was below the limit allowed for the commercialization. The composting carried out in all facultative reactors provided ideal conditions for the total sterilization of the final compost. Therefore, the treatment of smuggled cigarettes through facultative reactors was efficient to produce stable and mature compost.