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Item Treatment of domestic wastewater by association of up flow anaerobic and aerobic biofilters(2007) Srinikethan, G.; Shrihari, S.; Pradeepan, V.S.Laboratory studies were conducted to assess the performance of association of up flow anaerobic & aerobic biofilters in treating domestic wastewater. Two simple models of 8 litres capacity, one up flow anaerobic biofilter (AnBF) packed with support media granite of size 20 mm and another up flow aerobic biofilter(ABF) packed with support media granite of size 10 mm respectively were installed. The experimental anaerobic & aerobic biofilters were made of PVC tubes. The hydraulic retention time (HRT) was maintained as 12 hours in anaerobic biofilter and 8 hours in aerobic biofilter. The study was carried out for a period of 90 days. The association of up flow anaerobic & aerobic biofilters demonstrated the average Turbidity, Suspended Solids, BOD and COD removal 96.56%, 96.53%, 95.67% and 90.42% respectively. The waste treatment performance indicates that the association of up flow anaerobic & aerobic biofilters is a promising technique for (sub) tropical countries. Copyright � Enviromedia.Item Treatment of domestic wastewater in up flow anaerobic biofilters (using granite as packing material)(2005) Srinikethan, G.; Shrihari, S.; Pradeepan, V.S.Laboratory studies were conducted to assess the influence of media related factors such as porosity and pore size and specific surface area on performance of up flow anaerobic biofilters (ABFs). Two simple model of 8 litres capacity up flow anaerobic biofilters (ABFs), one packed with support media granite of size 50 to 40 mm and the other packed with granite of size 25 to 20 mm were installed. The experimental anaerobic biofilters were made of PVC tubes. The hydraulic retention time (HRT) was maintained as 12 hours. The study was carried out for a period of 90 days. The waste treatment performance indicates that the biofilter associated with media of the lesser pore size and porosity with higher specific surface area demonstrated the highest BOD and COD removal 91.03% and 82.50% respectively. Copyright � Enviromedia.Item Performance evaluation of sewage treatment plant - A case study(2004) Yaragal, S.C.; Shrihari, S.A study was conducted to assess the performance of the domestic wastewater treatment plant designed for the New Mangalore Port Trust (NMPT) township, Panambur. The data of raw, aerated and treated wastewater samples were collected for a period of 24 months (January - 1998 to December 1999) with a sampling frequency of one month. The sewage treatment plant is designed to treat an average flow of 1.2 MLD. The treatment scheme is based on extended aeration activated sludge process and consists of bar screens, collection sump, grit channel, aeration tank, secondary clarifier, treated sewage sump and sludge drying beds. The salient design features of the plant, process description, physico-chemical characteristics of sewage at different stages of treatment, sludge and grit are presented. Various parameters were tested in the laboratory and analyzed to assess the performance of the treatment plant. The effluent concentrations revealed that the treatment plant was found to be working quite satisfactorily though the influent wastewater quality was varying considerably. Enviromedia.Item Shear strength characteristics and chemical characteristics of leachate-contaminated lateritic soil(2009) Sunil, B.M.; Shrihari, S.; Nayak, S.Leachate is a hazardous liquid and is a major cause of concern in landfills. Numerous environmental problems such as soil and groundwater contamination occur in unlined landfills due to free flow of leachate. Large quantities of leachate-contaminated soils result from open dumping in the study area. These dump yards receive large quantities of municipal solid waste which includes chemical and industrial wastes. Large areas of land are currently being used for this purpose. An extensive laboratory testing program was carried out to determine the properties of clean and contaminated lateritic soils. Laboratory prepared municipal solid waste leachate was used in this study. Contaminated specimens were prepared by mixing the soils with MSW leachate in the increments of 0%, 5%, 10% and 20% by weight to vary the degree of contamination. The results showed that the MSW leachate affects the Atterberg limits, shear strength and chemical characteristics of the lateritic soils. The liquid limit and the plasticity index of the lateritic soils increases with MSW leachate concentration. For specimens tested at the Proctor density, effective cohesion increases and effective friction angle decreases due to increase in leachate concentration. This is attributed due to the increase in clay content of lateritic soil after interaction with the leachate. This led to increase in cohesion parameter and the friction angle decreases. The pH measurements of lateritic soil contaminated with MSW leachate indicated an increase in pH values. This is also accompanied by slight increase in the cation exchange capacity of the soil. The change in chemical characteristics of lateritic soil contributed due to addition of leachate may be detrimental to foundation concrete in real field conditions. The present work deals with an attempt to study the effect of leachate on the Atterberg limits, shear strength properties and chemical characteristics of lateritic soil. 2009 Elsevier B.V. All rights reserved.Item Reuse of incinerated textile mill sludge as adsorbent for dye removal(2015) Jahagirdar, S.S.; Shrihari, S.; Manu, B.Textile industry is one of the largest and oldest industries in India. Textile mill uses large quantities of water for its variety of wet processes, which in turn generates a large amount of waste water. Effluent treatment plants treat textile mill waste water using a variety of chemical coagulants thus producing greater amount sludge. Disposal of sludge is a challenging problem. In this study Textile mill sludge was incinerated at 800 C and used as an adsorbent without any activation. SEM images confirmed that, sludge ash was porous in nature and could be used as an adsorbent. For the entire study, Remazol blue dye was used. Experimental studies were carried out in an acidic pH range, showed good dye removal by using incinerated textile mill sludge ash. Experimental results obtained fitted well in Langmuir and Freundlich isotherms. 2015, Korean Society of Civil Engineers and Springer-Verlag Berlin Heidelberg.Item Organics and nutrients contributions by benthalsludges under continuously accumulating conditions(2000) Bhargava, D.S.; Shrihari, S.In this paper, the nutrient and organics release under continuously accumulating conditions of benthalsludge, the affect of frequency of addition and organic loading rates are analysed and discussed. The rate of organics release decrease with increasing time from start of experiment. The rate of organics release has been lower when the organics loading rate is less, and frequency of addition is more. However, the nutrients release is less when the frequency of addition is lower.Item Nutrient contributions by benthal sludge deposits(2009) Bhargava, D.S.; Shrihari, S.Settled solids from effluents discharged into a river system, undergoing decomposition at the river bottom, form an appreciable internal nutrient source for the biological activities in the river system. During the stabilization of benthal deposits, a variety of nutrients are released into the overlying waters. The exchange between sediment and overlying waters is a major component of the nitrogen and phosphorous cycles in the natural waters. The releases of such nutrients is a surface phenomenon, regulated by the conditions of benthal sludge layers, flow rate of overlying waters, etc. The rate of ammonia nitrogen release manifested an optimum low value when benthal sludge depth was 0.2 m, but was not influenced by the flow rate of overlying water and h/d ratios. The rate of phosphate release from benthal sludge was independent of depth of benthal sludge, flow rate and h/d ratios. The nutrients in the benthal sludge layers were increasing with time, and were concentrated at a layer 10 cm below the top surface. The nutrients release (percent of nutrient remaining in top benthal sludge layers) decreased with time and became almost constant after about 40 days. The nutrients release under continuously accumulating conditions of benthal sludge and me effects of frequency of addition have been discussed in this paper. The nutrients release was less when the frequency of addition was less.Item Modelling for organics and nutrients release during Benthal sludge stabilisation : Part I -organics(2008) Bhargava, D.S.; Shrihari, S.Settleable solids in the untreated and partially treated domestic and industrial effluents discharged into a river system undergoes settling and decomposition in the form of benthal sludge deposits, Early models of biochemical oxygen demand (BOD) assimilation in rivers do not account for the BOD contribution by these benthal sludge deposits. In this paper, a model for computations of the BOD contribution by benthos (both from the top aerobic layers and the leached portion of BOD from the bottom anaerobic layers) was presented. Observations from three sets of experiments at the chosen overlying water flow rates (500 ml/min, 1000ml/ min and 1500 ml/min) show a higher BOD contribution by benthos at higher overlying water flow rates. The ratio of the BOD contributions by benthos to the volatile solids in the top aerobic layers was lower when compared to the similar ratio in respect of the bottom layer volatile solids showing that a higher contribution was made by the top layers.Item Modelling for organics and nutrients release during benthal sludge stabilisation part il - Nutrients(2009) Bhargava, D.S.; Shrihari, S.Settleable solids from untreated or partially treated domestic and industrial effluents undergoing stabilisation in stream beds contain significant amount or nutrients such as ammonia and phosphates apart from carbonaceous organic material. An experimental investigation was carried out to study the contribution of biochemical oxygen demand (BOD) and nutrients by this benthal-sludge undergoing stabillisation in steam beds. Sludge was collected from a sewage channel and placed at the bottom of an experimental reactor, and a continuous flow of clean tap water was maintained, in such a manner that the sludge was not disturbed. The first part of this work contained a discussion on degreadation of carbonaceous matter. The degradation of the nutrients, such as ammonia and phosphates being released from the sediments into the overlying waters at different flow rates of over laying waters is evaluated. It was noticed that the ammonia and phosphates released from the sediments into the overlying waters become more or less uniform after some days. The ammonia release and phosphate release were found to be affected by changes in the flowrates of overlying waters. The ammonia and phosphates remaining in the top and bottom layers of the sediments also showed similar trends. Predictive models have been presented for the variation of ammonia and phophate release into the overlying water, ammonia and phosphates remaining in the sediment layers at different times and different flow rates.Item Hydraulic and compaction characteristics of leachate-contaminated lateritic soil(2007) Nayak, S.; Sunil, B.M.; Shrihari, S.Large quantities of leachate-contaminated lateritic soil results from dump yards in the southwest coast of India. These dump yards receive large quantities of municipal solid waste which includes chemical, industrial and biomedical wastes. Large areas of land are currently being used for this purpose. An extensive laboratory testing program was carried out to determine the compaction characteristics and hydraulic conductivity of clean and contaminated lateritic soil. Batch tests were used to study the immediate effect of leachate contamination on the properties of lateritic soil. Contaminated specimens were prepared by mixing the lateritic soil with leachate in the amount of 5%, 10% and 20% by weight to vary the degree of contamination. The results indicated a small reduction in maximum dry density and an increase in hydraulic conductivity due to leachate-contamination. The change induced by chemical reaction in the microstructure of the soil was studied by scanning electron microscope before and after contamination of soil with leachate. The structure of the leachate contaminated soil sample appeared to be aggregated in scanning electron microscope analysis. The aggregated structure increases the effective pore space and thus increases the hydraulic conductivity. Fifty percent increase in hydraulic conductivity was observed for specimens prepared at standard Proctor density and mixed with 20% leachate. Compaction characteristics did not change much with the presence of leachate up to 10%. With 20% leachate the maximum dry density decreased slightly indicating excess leachate in the soil. However the changes are not significant. 2007 Elsevier B.V. All rights reserved.