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

Investigation on Chemical Properties and the Maturation Degree of Vermicompost Obtained from Button Mushroom Production Process Waste

Introduaction: Development of mushroom cultivation in Iran is considered and its production level is reached to Ninety tons per year. About five kg of waste is generated by producing one kilogram of button mushroom which can be refined by using vermicompost technology. This waste can be converted into valuable organic fertilizer and reduce the use of chemical fertilizers and reach to sustainable development. The purpose of this study is to convert the button mushroom production process waste to manure and investigate the chemical properties and quality of the fertilizer. Methods: Wastes such as rotten mushroom, spent mushroom compost and peat are generated in cultivation process of Button mushroom that is large amounts of waste, and say it (SMC). In this study, SMC was vermicomposted in optimized process with treatment of wood chips, rotten mushrooms, carrots scum and leaves. Quantitative and qualitative indicators and its changes have been studied during the six weeks and the results achieved were compared with the national standard vermicompost (No. 13724) and its quality was determined in final product. Then by Using SPSS software, Pearson correlation test at a significance level of 0.05 were used to examine the relationship between inorganic materials and changes in other parameters and linear regression test were used to find relationships between one variable and the other variables. Results: The results showed that the Total Organic Carbon (TOC), potassium and total nitrogen in all treatments, increased during the time, however, pH and EC levels decreased during the vermicomposting process. Also significant increase in C/N ratio was observed in all treatments at the end of the six weeks and all the fertilizers were classified as one grade. Conclusion: Results of this research showed that vermicompost process Lead to improvement in indicators of organic fertilizers derived from vermicompost beds and is one of the management suitable methods for workshop wastes of button mushroom production that is a way to achieve sustainable agriculture

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