Plappally, Anand K

2019-07-01, Nighojkar, Amrita Kaurwar, Vijay, Ankisha, Kumavat, Ajay, Gupta, Sandeep, Satankar, Raj Kumar, Plappally, Anand K

This paper elaborates manufacture and performance analysis of new clay ceramic (CC) water filtration materials. The CC is manufactured from clay and sawdust mix. Waste marble powder and machined iron fines are used as additives to the mix for manufacturing the new modified materials. An equal volume of clay and sawdust were used to manufacture the control CC. Another ceramic, marble clay ceramic (MCC), was manufactured with distinct volume fractions of clay, sawdust, and marble (40:40:10). Third ceramic, ferrous clay ceramic (FCC), was manufactured from an equal volume of clay and sawdust and five percent by volume of iron fines. FCC showcased better arsenic (As (V)) contaminant removal from water at acidic pH while MCC showcased best As (V) removal at around pH of 8. Average flexural strength of MCC was comparatively better than FCC and CC. The modified materials showcased similar percolation rates at par with control CC. MCC showcased comparatively better E. coli removal capabilities than FCC and CC. Only limited volumetric addition of marble powder and iron fines were found to positively affect compressive strength. The results demonstrate new low-cost ways of modifying strength and specific water treatment characteristics of CC using waste materials from local marble-processing and iron-machining industries.

2017-06-01, Sharma, Pragati R., Soni, Vineet Kumar, Pandey, Shubham, Choudhary, Ganpat, Plappally, Anand K, Sharma, Rakesh Kumar

The current study involves a simple hydrazine based colorimetric chemo-sensor for selective determination of various anions. The anion-binding ability of the ligand with various anions via polar-non polar interactions and hydrogen bonding has been examined. The sensor displayed significant UV-vis enhancement response to anions such as fluoride, acetate, hydroxide, cyanide and hydrogen sulphate, with respect to concentration and time. The rate constants (K) and binding constants, Ka, for these anions have been measured by using Benesi-Hildebrand equation. A time dependent NMR study revealed stronger interaction for cyanide and fluoride ions among competing anions.

2015-09-25, Singh, Rattandeep, Gupta, Sandeep, Raman, S., Chakraborty, Prodyut Ranjan, Sharma, Puneet, Sharma, Rakesh Kumar, Brown, Larry C., Wei, Xiaohua, Plappally, Anand K

Abstract: A numerical visualization study of wetlands is detailed in this article using finite volume methods. The aim of this study is to model treatment efficiency of the wetlands in terms of the residence time distribution function. Shape and depth of wetlands are critically analysed to find the optimal flow requirement for effective treatment. Laminar three-dimensional flow dynamics is used to simulate the slow water flows that occur in treatment wetlands. Slow inlet flows are assumed. Dye is used as the tracer to characterize the hydrodynamics within the wetlands. Three different geometrical configurations, namely square, square with two islands, and triangle, respectively, are simulated. The variation in the tracer concentration is studied as a function of recirculation volumes, flow rates, time and depth of the wetland for each of the wetland shapes. The change in the variation of tracer concentration at inlet and exit helps to assess treatment effectiveness. In another case, glycerine is used to simulate sewage flow. Plug flow is prominent in sewage-laden wetlands. The results obtained from the above-illustrated case studies are compared with each other to assess the reproducibility of the optimal flow model. Multi-parameter regression models for residence time distribution functions are derived to characterize flow through constructed wetlands of different shapes.

2013-01-01, Wei, Xiaohua, Wang, Xiugui, Dong, Bing, Li, Xinjian, Plappally, Anand K, Mao, Zhi, Brown, Larry C.

The experimental farmland-channel-wetland systems (FCWS) in Guilin, China have been recently designed based on wetland water recycling systems in Midwest USA. The present article develops a methodology for simplifying the prediction of residence time as a function of the flow rate and physical shape of these contaminant removal systems. A series of two-dimensional simulation studies on surface flow through FCWS wetland of different shapes are performed. Parameters influencing hydraulic characteristics such as empirical values of inlet and outlet flow conditions, and wetland shapes are utilized as inputs to the study. Roughness coefficient was assumed to be constant across the different wetland designs discussed in this article. The mean velocity values within the wetland decreases with increase in ratio of variant inlet widths and wetland inflow rates. The results from the simulation are used as inputs for performing a multivariate multiparameter regression algorithm. This framework models the residence time within the wetland independently as a function of shape, mass inflow, and inlet geometry. This simplified model can be used with ease to evaluate existing as well as new wetland system designs for potential improvement in its function of desalting and filtering waters. © 2013 Desalination Publications. All rights reserved.

2015-09-04, Choudhary, Ganpat, Sharma, Rakesh Kumar, Plappally, Anand K

The article elaborates the development of gravity-based water filtration systems capable of removing fluoride using natural organic material. In this study, the precipitation and dissolution reaction occurring in suspension of hydroxyapatite (HAP) as addition of fluoride were investigated under well-defined condition. This process is set to occur in a quasi-static gravity-based water filter system. This system is a (pond sand, organic material (gaur seed powder, neem, sesame sawdust, and Ayurvedic waste), water, and HAP mixture) composite ceramic. This article illustrates these ceramic material systems manufactured using distinct permutations of pond sand and organic materials. HAP is introduced into the composite mix of pond sand and organic materials to manufacture some of the sintered ceramic filtration material systems tested here. The fluoride removal efficiency of these variant systems is discussed. The energy dispersive X-ray spectroscopy studies of the ceramics provided the mineral content within the system variants. At high temperatures beyond 600°C, the sintered hydroxyapatite is observed to have a microstructural transformation from amorphous to crystalline. The surface properties of these sintered as well as raw materials used in the production of the ceramic composite are also investigated. A mathematical multivariate regression model is derived providing a relationship between the effectiveness of the water filtration systems as a function of the raw material composition and properties. The Ayurvedic waste material was found to be a good substitute for HAP for fluoride removal. The proposed treatment system is appropriate and suitable approach for fluoride removal in rural areas, because of its simplicity and easy operation and handling. Since Ayurvedic and organic waste materials are easily available at low cost, the proposed method is very suitable for the people living in low-income rural areas of developing countries like India.

2015-09-25, Gupta, Sandeep, Singh, Rattandeep, Chakraborty, Prodyut Ranjan, Sharma, Rakesh Kumar, Soboyejo, A. B.O., Wei, Xiaohua, Plappally, Anand K

Abstract: Empirical stochastic multi-variable models for prediction of treatment efficiency of wetlands are presented in this article. Wetlands of seven different shapes are visualized using tracer studies. Two different variants of experiments are carried out. Numerous flow rate variations are performed keeping surface area of the wetland constant. The experiment is also carried out with a variation in volume of the wetland which helps to study the effect of flow height on the hydrodynamics within the wetland. A multi-variable model for treatment efficiency in terms of change in tracer concentration as a function of shape, volumetric height of water within the wetland, time, and mass flow rate is considered. Further, another set of experiments is performed studying the treatment efficiency in terms of electro-kinetic parameters. This involves measuring the pH, turbidity, temperature, electrical conductivity, total dissolved salts at inlet and outlet and residence time with varying flow rate, and height of water for the seven different wetland models under study. The electro-kinetic parameters changes due to difference in concentration of the tracer dye which simulates impurities. In this case, treatment efficiency is expressed as a function of the above-discussed electro-kinetic variables, time variation, water height, as well as variation in the mass flow rate. The stochastic multi-parameter models, thus, empirically derived in the above two cases have high coefficient of determination. The models thus derived may be used as a tool for quick analysis of treatment efficiency of any shape and size of a three-dimensional wetland.

2013-07-01, Yakub, Ismaiel, Plappally, Anand K, Leftwich, Megan, Malatesta, Karen, Friedman, Katie C., Obwoya, Sam, Nyongesa, Francis, Maiga, Amadou H., Soboyejo, Alfred B.O., Logothetis, Stefanos, Soboyejo, Wole

This paper presents the results of an experimental study of the effects of porosity on the flow rate and Escherichia coli (E. coli) filtration characteristics of porous ceramic water filters (CWFs) prepared without a coating of silver. Clay-based CWFs were fabricated by sintering composites of redart clay and fine woodchips (sawdust) in three different proportions by volume, viz: 50:50, 65:35, and 75:25. Sintering the greenware below 1,000 C produced reddish colored pot of three different degrees of porosity and micro-and nanoscale pores, which are the key to efficient filtration. The porosities and pore size distribution frequencies of the sintered clay ceramics were characterized using mercury intrusion porosimetry (MIP). The porosity of the CWFs ranged from ∼36% to ∼47% and increased with increasing sawdust content in a linear fashion, and the pore size varied from ∼10 nm to ∼100 μm. The volume flow rates of water through the CWFs were investigated by measuring the cumulative amount of water flow as a function of time. The flow rate was found to increase with increasing porosity of the CWFs. The effective intrinsic permeabilities of the CWFs were then obtained from Darcy fits to the flow rate data. These were compared with values obtained using the Katz-Thompson method. Both approaches gave comparable results of permeability between ∼1 millidarcy to ∼50 millidarcy. The tortuosity of the CWFs was found from Hager's equation to range from ∼10 to ∼60. In general, while the permeability of the CWFs decreased with increasing clay content, tortuosity increased with increasing clay content. The CWFs removed E. coli from aqueous suspension very efficiently with average log reduction values between 5.7-6.4. The implications and limitations of the results are discussed for the effective filtration of water in the developing world. © 2013 American Society of Civil Engineers.

2015-09-18, Yadav, A., Kumar, Gaurav, Soboyejo, A. B.O., Gaur, R. S., Tiwari, S, Plappally, Anand K

Abstract: Column reactor models of volume size 3,000  and 1,500 cm3 are made using organic materials such as sawdust and immature (drumstick) Moringa oleifera and other natural materials such as gravels (6 mm size) and ball clay available locally at Jodhpur, India. Water is passed through these porous reactors under gravity at once. The experiments were aimed at finding low-cost solutions for wastewater or sewage disposal at point of use. The change in pH during water filtration experiments is measured and modelled as functions of X1 (column height), X2 (flow rate), X3 (cumulative percolation time) and X4 (change in electrical conductivity). The parameters X1, X2, X3 and X4 are found to be highly correlated to each other irrespective of materials used for making the bioreactors. There is a hyperbolic relationship between temperature gradient within the porous material column bed through which water is percolating and time taken during that process. The temperature distribution in the gravel or sawdust media reactors is not influenced by the inflow rate or height of the reactor column used for experimentation. Distinct temperature distribution exists at each depth of the heterogeneous reactors. The multi-parameter model developed and the hyperbolic relationships help to characterize the efficacy of bioreactors. The effect of the materials on the wastewater treatment can now be individually evaluated using the multi-parameter approach presented in this paper.