Effect of silver nanoparticles for Coli forms disinfection in drinking water

Background and aims: Silver is the metal as a safe and effective antibacterial agent which can be raised more than 650 types of microorganisms such as bacteria and virus. Common indicator used to assess water quality and compliance with standards to determine the presence of total coli forms and fecal coli forms are bacteria. The aim of this study was to evaluate the effect of nanosilver on inactivation the coli forms and fecal coli forms from drinking water. Methods: This bench-scale experimental study was carried out in a batch system on artificially contaminated water samples prepared by adding 10 ml effluent to 90 liters of distilled water. In each run, the nanosilver (30-180 μgL) was added to 6 containers of contaminated water and then a sample was taken every 20 minutes for a 100-minute period. The samples were tested by 15-tube series method based on the instruction no. 9221-B of 21th edition of standard method book on water and wastewater experiments (21st edition). Results: Results revealed that the coli forms and fecal coli forms inactivation significantly increased with increasing the contact time of nonosilver (P=0.001), but there was no significant correlation between the nanosilver concentrations and coli forms and fecal coli forms inactivation (P=0.13). The maximum coli forms and fecal coli forms inactivation (76.2, 65%) was achieved within 100 minutes contact time for 180 μgL of silver. Conclusion: Based on the current results, it can be concluded nanosilver treatment is effective in coli forms and fecal coli forms inactivation from contaminated water and advice as a new method for water disinfection

Application of artificial neural network and multiple linear regression in modeling nutrient recovery in vermicompost under different conditions

© 2020 Elsevier Ltd Vermicomposting is one of the best technologies for nutrient recovery from solid waste. This study aims to assess the efficiency of Artificial Neural Network (ANN) and Multiple Linear Regression (MLR) models in predicting nutrient recovery from solid waste under different vermicompost treatments. Seven chemical and biological indices were studied as input variables to predict total nitrogen (TN) and total phosphorus (TP) recovery. The developed ANN and MLR models were compared by statistical analysis including R-squared (R2), Adjusted-R2, Root Mean Square Error and Absolute Average Deviation. The results showed that vermicomposting increased TN and TP proportions in final products by 1.5 and 16 times. The ANN models provided better prediction for TN and TP with R2 of 0.9983 and 0.9991 respectively, compared with MLR models with R2 of 0.834 and 0.729. TN and C/N ratio were key factors for TP and TN prediction by ANN with percentages of 17.76 and 18.33

Generators for the elliptic curve E(p,q):y2=x3−p2x+q2E_{(p,q)} : y^2 = x^3 - p^2x + q^2

Let $\{E_{(p,q)}\}$ be a family of elliptic curves over a rational field such that we have $E_{(p,q)} : y^2 = x^3 - p^2x + q^2$, where $p$ and $q$ are prime numbers greater than five. Earlier work showed that the elliptic curve $E_{(p,q)}$ had ranked at least two for all $p, q > 5$ and two independent points. This paper shows that two points that can be extended to a basis for $E_{(p,q)}$ under conditions are confident that we will fully recover.Comment: 4 pag

Evaluation of the Biosolids Compost Maturity in South Isfahan Wastewater Treatment Plant

The composting process is a useful method of producing a stabilized material that can be used as a source of nutrients and soil conditioner. Maturity of compost is essential for its optimal use as a soil amendment and a source of plant nutrients as well. Immature composts pose problems of malodors and flies and phytotoxicity and pollution during use. Stability and maturity both are required for compost quality control. Compost maturity tests can be classified into physical, chemical, plant, and microbial activity assays. In this study, several methods of evaluating the stability and maturity of composted biosolids were compared based on chemical and biological properties. The sludge used of windrow composting was obtained from the drying beds of South Isfahan wastewater treatment plant. The results showed that, C/N ratio after 100 days of composting reached to 15/1; NH4/NO3 ratio decreased with increase of the time dewatered sludge compost, which this loss is 57.3%. The content of volatile solids, 28.8% decreased with composting time. The number of fecal coliforms in the initial sewage sludge compost was 17.9×106 and at the end of composting was 898MPN/g of total solids and the compost process provided class A pathogen criteria. Use of chemical and biological parameters exhibited three phases: rapid decomposition (day 40), stabilization (day 80) and maturation (day 100) in biosolids compost. Thus, the biosolid compost was mature and ready for use as an agricultural substrate after about 100 days of composting

Evaluation of the Biosolids Compost Maturity in South Isfahan Wastewater Treatment Plant

The composting process is a useful method of producing a stabilized material that can be used as a source of nutrients and soil conditioner. Maturity of compost is essential for its optimal use as a soil amendment and a source of plant nutrients as well. Immature composts pose problems of malodors and flies and phytotoxicity and pollution during use. Stability and maturity both are required for compost quality control. Compost maturity tests can be classified into physical, chemical, plant, and microbial activity assays. In this study, several methods of evaluating the stability and maturity of composted biosolids were compared based on chemical and biological properties. The sludge used of windrow composting was obtained from the drying beds of South Isfahan wastewater treatment plant. The results showed that, C/N ratio after 100 days of composting reached to 15/1; NH4/NO3 ratio decreased with increase of the time dewatered sludge compost, which this loss is 57.3%. The content of volatile solids, 28.8% decreased with composting time. The number of fecal coliforms in the initial sewage sludge compost was 17.9×106 and at the end of composting was 898MPN/g of total solids and the compost process provided class A pathogen criteria. Use of chemical and biological parameters exhibited three phases: rapid decomposition (day 40), stabilization (day 80) and maturation (day 100) in biosolids compost. Thus, the biosolid compost was mature and ready for use as an agricultural substrate after about 100 days of composting

Heavy Metals Bioaccumulation by Iranian and Australian Earthworms (Eisenia fetida ) in the Sewage Sludge Vermicomposting

Vermicomposting of organic waste has an important part to play in an integrated waste management strategy. In this study, the possibility of heavy metals accumulation with two groups of Iranian and Australian earthworms in sewage sludge vermicompost was investigated. Eisenia fetida   was the species of earthworms used in the vermicomposting process. The bioaccumulation of Cr, Cd, Pb, Cu, and Zn as heavy metals by Iranian and Australian earthworms was studied. The results indicated that heavy metals concentration decreased with increasing vermicomposting time. Comparison of the two groups of earthworms showed that the Iranian earthworms consumed higher quantities of micronutrients such as Cu and Zn comparing with the Australian earthworms, while the bioaccumulation of non-essential elements such as Cr, Cd, and Pb by the Australian group was higher. The significant decrease in heavy metal concentrations in the final vermicompost indicated the capability of both Iranian and Australian E.fetida species in accumulating heavy metals in their body tissues

Ionic liquid-assisted sol-gel synthesis of Fe2O3-TiO2 for enhanced photocatalytic degradation of bisphenol a under UV illumination: Modeling and optimization using response surface methodology

This study was undertaken to synthesize Fe2O3-doped TiO2 nanoparticles using a long tail ionic liquid-assisted sol-gel method (IL-Fe2O3/TiO2) in order to photodegrade bisphenol A (BPA). Physicochemical properties of the synthesized photocatalysis were characterized through FTIR, FESEM-EDX, XRD, and DRS. The modeling and optimization of the photodegradation of BPA by IL/ Fe2O3-TiO2 were conducted with response surface methodology (RSM) by considering the central composite design (CCD). The results revealed that the 1-octadecyl-3-methylimidazolium bromide (OMDBr) ionic liquid, in combination with ferric oxide dopant, created low aggregated nanocomposites with a uniform and tiny grain size. 2.4 eV. bandgap energy was computed for IL-Fe2O3/TiO2. The quadratic model obtained from the ANOVA results of photodegradation processes. A BPA removal efficiency of 90.33 % was acquired under optimal conditions (IL-Fe2O3/TiO2 loading dose = 0.75 g/L, pH = 9, initial BPA concentration = 10 mg/L, and UV irradiation time = 97.5 min). The results indicated that the photodegradation of BPA was mostly affected by the variables of time, pH, and initial BPA concentration, respectively. Only the second term of the IL-Fe2O3/TiO2 loading dose as a variable had a significant effect on the efficiency of the process. The Langmuir�Hinshelwood model was selected to investigate photodegradation kinetics. © 2020 Elsevier Gmb