Optimizing nutrients from fly ash-amended soil through microbial-assisted phytoremediation using response surface methodology.

Nutrients are vital ingredients to boost plant health. The availability of nutrients is limited in fly ash (FA) waste to properly implement phytoremediation. The research explored the integration of microbes and treated wastewater irrigation in phytoremediation to provide the necessary nutrients for plant growth in fly ash-amended soils. The Box-Behnken method was used to design the experimental layout for the pot study. Response surface methodology (RSM) was applied as the optimization approach to model predictions for nutrient accumulation. The implemented pot study attained the highest morphological indicators with a plastochron index of 33.40, an absolute growth rate of 2.63 cm/day, and a leaf area of 2681.68 cm2 and attained maximum biomass of 24.91 g for the treatments that included a mid-range of the variables. The combination of FA 14.98%, microbial dose 4.07 mL, and treated wastewater as the irrigation source was found to be the optimized combination for nitrogen and phosphorus accumulation of 212.4 and 8.867 mg/L.

Response surface method for optimization of process variables for bioaccumulation of metals with Jatropha curcas on fly ash-amended soil.

Heavy metal contamination is a serious rising issue with the dumping of fly ash (FA). A recent focus of researches and practices tends towards reutilization of FA with bioremediation technique using various plants. The present research aimed to investigate optimum metal extraction in fly ash-amended soil using microbes and treated wastewater with Jatropha curcas plant using response surface methodology (RSM). The Box-Behnken design was used to determine the optimum condition for maximum metal remediation with three levels and three variables, viz., fly ash percentage (5, 12.5, 20%), microbial dose (0.5, 5.25, 10 ml), and contaminant level of water to irrigate the plant (freshwater, treated wastewater, untreated wastewater). The approach adopted was to set fly ash percentage as "maximum," microbial dose as "minimum," and contaminant level of water to irrigate the plant as "in range." The outcome of the present research provided the best prediction models, integrated the process variables, and developed rotational curves for analyzing metal remediation in 360° rotation for Fe, Mn, Zn, Cu, and Al as responses of interest. The optimum conditions for maximum bioremediation from fly ash-amended soils by bioaccumulation on Jatropha curcas plant worked out as 13.866% fly ash, 4.088 ml microbial dose, and treated wastewater as type of water to irrigate the plant that bioaccumulated Fe, Mn, Zn, Cu, and Al as to 26.904, 0.760, 0.160, 0.162, and 12.895 mg/l.

Utilization of isolated microbe and treated wastewater for enhanced growth of Jatropha curcas for bioremediation of fly ash amended soil.

The generation of Fly Ash (FA) waste is continuously piling up with the increasing energy demand. Recent research is focused towards reutilizing this fly ash waste through bioremediation practices. But fly ash retards the growth of plants and holds back to support the bioremediation process due to a deficiency of essential main nutrients. The present research envisages overcoming this problem by providing a novel concept of inducing isolated microbes and treated wastewater which provides necessary nutrients and promotes better plant growth and metal extraction. A pot experimental study was executed with treatments T1 (FA amended soil), T2 (FA with isolated microbe), and T3 (FA with microbes and treated wastewater). As an outcome of the present research, T3 gained relatively higher morphological characteristics viz. Leaf area (29.8%), absolute growth rate (61.7%), plastochron index (18.6%), biomass yield (47.3%) and enhanced metal extraction for Fe (34.4%), Al (27.1%), Mn (72.0%), Zn (17.5%) in comparison to the control. Treatment T3 also gained higher Remediation Efficiency (RE) and Bio-Concentration Factor (BCF) values for Al, Fe, and Mn. The involvement of nutrients via treated wastewater energizes the process mechanism and increases the working zone for the microbes thereby, enhancing the bioremediation.

Sustainable amelioration of fly ash dumps linking bio-energy plantation, bioremediation and amendments: A review.

Disposal of fly ash in dumps is posing serious environmental problem causing air pollution, groundwater contamination, and loss of valuable land making it unproductive dumpsites. Cultivation of plants using bioremediation technique is looked upon as one of the sustainable remedial solution to these fly ash dumpsites. In recent years, researches on the plantation of bio-energy crops over the fly ash dumpsites is creating renewed interest, as it serves remediation along with distinct energy outcomes creating a win-win situation. The issue of the slow growth of plants, due to lack of nutrients and microbial activities is being resolved through advances in bioremediation research done in conjunction with organic matter, microbial inoculants, and inclusion of wastewater. New researches are being done with different plants and microbes in the matrix combination and use wastewater to supplement nutrients requirement to find eco-friendly & sustainable solutions. The present paper critically reviews the research on bioremediation and amendments with specific to bio-energy plantation on fly ash dumps.

Optimization of defluoridation using Ficus benghalensis leaf biosorbent through Taguchi's method.

Present research focuses on optimization of process parameters for defluoridation on novel Ficus benghalensis leaf biosorbent using Taguchi design tool. The maximum fluoride removal is obtained at pH 7, initial concentration 5 mg/L, contact time 120 min, adsorbent dose 10 g/L, and temperature 30°C, and its percentage contribution is found using ANOVA in the following order: pH 50.76% > initial concentration of adsorbate 44.76% > contact time 2.54% > adsorbent dose 1.17% > temperature 0.76%. It follows Langmuir isotherm with constants "a" and "b" obtained as 2.183 mg/g and 0.667 L/mg and fitting well with pseudo-second-order kinetic model. The thermodynamic study indicated the spontaneous and endothermic nature (ΔH = 15,530.55 J/mol). Advanced Analyses, viz., BET, FESEM-EDS, and FTIR are done to know the characteristics of Ficus benghalensis leaf biosorbent. Experiment on defluoridation of contaminated groundwater indicated over 90% removal efficacy, and the concentration of treated water satisfies drinking water standards for fluoride. PRACTITIONER POINTS: A fundamental research leading towards development of a novel biosorbent from Ficus benghalensis leaves waste for defluoridation. Necessary adsorption equilibrium, kinetic and thermodynamic studies to arrive at optimum operating parameters using Taguchi method and constants useful for designing defluoridation unit and advanced analysis mainly BET, FESM-EDS and FTIR to have better insight. Validation on real field samples to prove its technical feasibility of defluoridation using the novel biosorbent developed.