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Taikan Oki – One of the best experts on this subject based on the ideXlab platform.
Estimation of the effects of chemically-enhanced treatment of urban sewage system based on life-cycle managementSustainable Cities and Society, 2013Co-Authors: Goro Mouri, Satoshi Takizawa, Kensuke Fukushi, Taikan OkiAbstract:
Effluent requirements have frequently been established that are more stringent than those traditionally considered possible using biological secondary treatment. We evaluated aeration energy and CO2 emissions using an inorganic polymer Coagulant of polysilicato-iron (PSI) as a pre-treatment alternative to an Aluminium Coagulant. Use of the PSI Coagulant for CO2 reduction was evaluated in terms of the effects on the quality of the treated water and overall cost effectiveness using a simplified life-cycle assessment (LCA) technique for a wastewater treatment system in an urban catchment. The water quality improvement effects of the wastewater treatment were evaluated by calculating the flux change according to the water quality characteristics in an urban catchment using a catchment simulator. The system evaluated, in an integrated manner, the quality of the treated water and the CO2 emissions from a wastewater treatment system. The effects of wastewater treatment management measures were assessed by evaluating their CO2 emissions and cost, in addition to the water quality improvement. A flocculating agent was used at a concentration close to the water quality standard, and a major effect was seen in terms of reduced aeration energy costs and CO2 emissions. Model calculations of the cost of using flocculating agents, such as polyAluminium chloride (PAC), PSI, ferric chloride, and a polymer Coagulant, indicated that the most economical agent was PSI with a polymer. For a cost burden of about 200 million JPY per year, including the cost of the flocculant and of sludge disposal, the CO2 emissions could be reduced by approximately 30%. Thus, a reduced energy technology was established to optimally manage catchment wastewater.
Karin Granström – One of the best experts on this subject based on the ideXlab platform.
Experimental study and analysis of the functional and life-cycle global warming effect of low-dose chemical pre-treatment of effluent from pulp and paper millsJournal of Cleaner Production, 2018Co-Authors: Maria Sandberg, Govindarajan Venkatesh, Karin GranströmAbstract:
Abstract Aeration, as a process in pulp and paper wastewater treatment, uses the greatest share of the energy. Therefore, if the energy efficiency of the treatment has to be improved, the focus must be on aeration. A key finding from the trials conducted for this paper, with effluent from a paper and pulp mill, was that the oxygen transfer coefficient could be doubled and the chemical oxygen demand could be decreased by 25%, if the effluent was pre-treated with 30 mg/l of Aluminium Coagulant (equivalent to 9.4 tonnes per day of AVR to 20000 cubic metres of effluent). Decrease in oxygen requirement implies decreases in aeration energy use. Pulp and paper mill effluents are not as biodegradable as municipal sewage, and the improvement in oxygen transfer properties of the effluent will have a positive influence over a longer period of time in the biological treatment. If the sludge is digested anaerobically, pre-treatment will also result in doubling the potential for methane generation. A holistic analysis of modifications to processes entails a study of the economic and environmental consequences as well. While the economic aspect is beyond the scope of this paper, only the net global warming as an environmental impact category has been studied, by taking recourse to specific emission coefficients. Of the four dosages of ferric Aluminium sulphate considered in this analysis, the net greenhouse gas emissions are the least – 426 kg carbon dioxide equivalent per day when the daily consumption is 9.4 tonnes.
Mette Myrmel – One of the best experts on this subject based on the ideXlab platform.
Coagulant residues’ influence on virus enumeration as shown in a study on virus removal using Aluminium, zirconium and chitosan.Journal of Water and Health, 2018Co-Authors: Ekaterina Christensen, Mette MyrmelAbstract:
Research on microorganism reduction by physicochemical water treatment is often carried out under the assumption that the microbiological enumeration techniques are not affected by the presence of Coagulants. Data presented here indicate that bacteriophage enumeration by plaque assay and RT-qPCR (reverse transcription quantitative polymerase chain reaction) can be affected by these water treatment chemicals. Treatment of water samples with an alkaline protein-rich solution prior to plaque assay and optimization of RNA extraction for RT-qPCR were implemented to minimize the interference. The improved procedures were used in order to investigate reduction of three viral pathogens and the MS2 model virus in the presence of three Coagulants. A conventional Aluminium Coagulant was compared to alternative agents (zirconium and chitosan) in a coagulation-filtration system. The highest virus reduction, i.e., 99.9-99.99%, was provided by chitosan, while Aluminium and zirconium reduced virus by 99.9% in colour-rich water and by 90% in water with less colour, implying an effect of Coagulant type and raw water quality on virus reduction. Although charge characteristics of viruses were associated with virus reduction, the results reveal that the MS2 phage is a suitable model for aggregation and retention of the selected pathogens.