scholarly journals Gas composition of sludge residue profiles in a sludge treatment reed bed between loadings

2017 ◽  
Vol 76 (9) ◽  
pp. 2304-2312
Author(s):  
Julie D. Larsen ◽  
Steen M. Nielsen ◽  
Charlotte Scheutz
Keyword(s):  
Pore Space ◽  
Biological Processes ◽  
Gas Composition ◽  
Total Emission ◽  
Sludge Treatment ◽  
Ch4 Concentration ◽  
Reed Bed ◽  
Carbon Dioxide Co2 ◽  
By Products ◽  
Resting Period

Abstract Treatment of sludge in sludge treatment reed bed systems includes dewatering and mineralization. The mineralization process, which is driven by microorganisms, produces different gas species as by-products. The pore space composition of the gas species provides useful information on the biological processes occurring in the sludge residue. In this study, we measured the change in composition of gas species in the pore space at different depth levels in vertical sludge residue profiles during a resting period of 32 days. The gas composition of the pore space in the sludge residue changed during the resting period. As the resting period proceeded, atmospheric air re-entered the pore space at all depth levels. The methane (CH4) concentration was at its highest during the first part of the resting period, and then declined as the sludge residue became more dewatered and thereby aerated. In the pore space, the concentration of CH4 often exceeded the concentration of carbon dioxide (CO2). However, the total emission of CO2 from the surface of the sludge residue exceeded the total emission of CH4, suggesting that CO2 was mainly produced in the layer of newly applied sludge and/or that CO2 was emitted from the sludge residue more readily compared to CH4.

Economic assessment of sludge handling and environmental impact of sludge treatment in a reed bed system

2015 ◽  
Vol 71 (9) ◽  
pp. 1286-1292 ◽  
Author(s):  
Steen Nielsen
Keyword(s):  
Environmental Impact ◽  
Agricultural Land ◽  
Operating Cost ◽  
Cost Savings ◽  
Economic Assessment ◽  
Land Application ◽  
Sludge Dewatering ◽  
Sludge Treatment ◽  
Significant Saving ◽  
Reed Bed

The effect on the environment of the establishment and operation of a sludge treatment reed bed system (STRB) is quite limited compared to mechanical sludge dewatering, with its accompanying use of energy and chemicals. The assessment presented here of the investment, operation and maintenance costs of a typical STRB, and of the related environmental impact, is based on the experiences gained from the operation of a large number of STRB in Denmark. There are differences in the environmental perspectives and costs involved in mechanical sludge dewatering and disposal on agricultural land compared to STRB. The two treatment methods were considered for comparison based on a treatment capacity of 550 tons of dry solids per year and with land application of the biosolids in Denmark. The initial capital cost for STRB is higher than a conventional mechanical system; however, an STRB would provide significant power and operating-cost savings, with a significant saving in the overall cost of the plant over 20–30 years. The assessment focuses on the use of chemicals, energy and greenhouse gas emissions and includes emptying, sludge residue quality and recycling. STRB with direct land application is the most cost-effective scenario and has the lowest environmental impact. A sludge strategy consisting of an STRB will be approximately DKK 536,894–647,636 cheaper per year than the option consisting of a new screw press or decanter.

scholarly journals Green Concrete: By-Products Utilization and Advanced Approaches

2019 ◽  
Vol 11 (19) ◽  
pp. 5145 ◽  
Author(s):  
Al-Mansour ◽  
Chow ◽  
Feo ◽  
Penna ◽  
Lau
Keyword(s):  
Carbon Footprint ◽  
Review Paper ◽  
Rice Husk Ash ◽  
Sustainable Concrete ◽  
Coarse Aggregates ◽  
Natural Aggregates ◽  
Carbon Dioxide Co2 ◽  
Furnace Slag ◽  
By Products ◽  
Slag Waste

The popularity of concrete has been accompanied with dreadful consumptions that have led to huge carbon footprint in our environment. The exhaustion of natural resources is not yet the problem, but also the energy that is needed for the fabrication of the natural materials, in which this process releases significant amount of carbon dioxide (CO2) emissions into the air. Ordinary Portland Cement (OPC) and natural aggregates, which are the key constituents of concrete, are suggested to be recycled or substituted in order to address the sustainability concern. Here, by-products have been targeted to reduce the carbon footprint, including, but not limited to, fly ash, rice husk ash, silica fume, recycled coarse aggregates, ground granular blast-furnace slag, waste glass, and plastic. Moreover, advanced approaches with an emphasis on sustainability are highlighted, which include the enhancement of the hydration process in cement (calcium-silicate hydrate) and the development of new materials that can be used in concrete (e.g. carbon nanotube). This review paper provides a comprehensive discussion upon the utilization of the reviewed materials, as well as the challenges and the knowledge gaps in producing green and sustainable concrete.

Correlation of Landfill and Digester Gas Composition With Gas Turbine Pollutant Emissions

2006 ◽  
Author(s):  
V. G. McDonell ◽  
M. W. Effinger ◽  
J. L. Mauzey
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Wastewater Treatment Plants ◽  
Quantitative Relationship ◽  
Pollutant Emissions ◽  
Systematic Effect ◽  
Gas Composition ◽  
Emission Regulations ◽  
Carbon Dioxide Co2

The deployment of small gas turbines at landfills and wastewater treatment plants is attractive due to the availability of waste fuel gases generated at these sites and the need for onsite power and/or heat. The fuel gases produced by these applications typically contain 35 to 75% of the heating value of natural gas and contain methane (CH4) diluted primarily with carbon dioxide (CO2) and sometimes nitrogen (N2). Demonstrations of 30 to 250 kW gas turbines operating on these waste fuels are underway, but little detailed information on the systematic effect of the gas composition on performance is available. Growth in the use of small gas turbines for these applications will likely require that they meet increasingly stringent emission regulations, creating a need to better understand and to further optimize emissions performance for these gases. The current study characterizes a modified commercial natural gas fired 60 kW gas turbine operated on simluated gases of specified composition and establishes a quantitative relationship between fuel composition, engine load, and emissions performance. The results can be used to determine the expected impact of gas composition on emissions performance.

Musk fragrances, DEHP and heavy metals in a 20 years old sludge treatment reed bed system

2012 ◽  
Vol 46 (12) ◽  
pp. 3889-3896 ◽  
Author(s):  
Víctor Matamoros ◽  
Loc Xuan Nguyen ◽  
Carlos A. Arias ◽  
Steen Nielsen ◽  
Maria Mølmer Laugen ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Sludge Treatment ◽  
Musk Fragrances ◽  
Reed Bed

Reed beds: constructed wetlands for municipal wastewater treatment plant sludge dewatering

2001 ◽  
Vol 44 (11-12) ◽  
pp. 393-398 ◽  
Author(s):  
J.S. Begg ◽  
R.L. Lavigne ◽  
P.L.M. Veneman
Keyword(s):  
Wastewater Treatment ◽  
Total Phosphorus ◽  
Biochemical Oxygen Demand ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Total Suspended Solids ◽  
Sludge Dewatering ◽  
Sludge Treatment ◽  
Reed Beds ◽  
Reed Bed

Reed beds are an alternative technology wastewater treatment system that mimic the biogeochemical processes inherent in natural wetlands. The purpose of this project was to determine the effectiveness of a reed bed sludge treatment system (RBSTS) in southern New England after a six-year period of operation by examining the concentrations of selected metals in the reed bed sludge biomass and by determining the fate of solids and selected nutrients. Parameters assessed in both the reed bed influent and effluent: total suspended solids, biochemical oxygen demand, nitrate-nitrogen and total phosphorus. In addition, the following metals were studied in the reed bed influent, effluent and Phragmites plant tissue and the sludge core biomass: boron, cadmium, chromium, copper, iron, lead, manganese, molybdenum, nickel, and zinc. The removal efficiencies for sludge dewatering, total suspended solids and biochemical oxygen demand were all over 90%. Nitrate and total phosphorus removal rates were 90% and 80% respectively. Overall metals removal efficient was 87%. Copper was the only metal in the sludge biomass that exceeded the standards set by the Massachusetts Department of Environmental Protection for land disposal of sludge. The highest metal concentrations, for the most part, tended to be in the lower tier of the sludge profile. The exception was boron, which was more concentrated in the middle tier of the sludge profile. The data and results presented in this paper support the notion that reed bed sludge treatment systems and the use of reed beds provide an efficient and cost effective alternative for municipal sludge treatment.

scholarly journals Sewage sludge and waterworks sludge stabilization in sludge treatment reed bed systems

2017 ◽  
Vol 76 (2) ◽  
pp. 355-363 ◽  
Author(s):  
Grazia Masciandaro ◽  
Eleonora Peruzzi ◽  
Steen Nielsen
Keyword(s):  
Organic Matter ◽  
Point Of View ◽  
Pyrolysis Gas ◽  
Organic Matter Quality ◽  
Sludge Treatment ◽  
Chromatography Analysis ◽  
Sludge Stabilization ◽  
Study Results ◽  
Reed Bed ◽  
Waterworks Sludge

In this study, results about sludge stabilization in sludge treatment reed bed (STRB) systems in two different systems, Hanningfield STRB 1 (England), treating waterworks sludge, and Stenlille STRB 2 (Denmark), treating surplus activated sludge, are presented. The study mainly focused on the effectiveness of the STRBs systems in stabilizing sludge organic matter; in fact, parameters correlated to biochemical and chemico-structural properties of organic sludge matter were determined. Dewatering and sludge stabilization were effective in both STRBs, as highlighted by total and volatile dry solids trend. β-glucosidase, phosphatase, arylsulphatase, leucine amino-peptidase and butyrate esterase activities, enzymes related to C, P, S, N and overall microbial activity, respectively, significantly declined along the profile in both STRBs. The determination of humic carbon highlighted the formation of a stable nucleus of humified organic matter in both STRBs in the deepest layers, thus meaning the successful stabilization of sludge organic matter for both kind of sludges. Similar conclusions can be drawn from pyrolysis gas chromatography analysis (Py-GC), which enables the characterization of soil organic matter quality from a chemical-structural point of view. The pyrolytic indices of mineralization and humification showed that in both STRBs the sludge organic matter is well stabilized.

scholarly journals A competitive advantage through fast dead matter elimination in confined cellular aggregates

2021 ◽  
Author(s):  
Yoav G. Pollack ◽  
Philip Bittihn ◽  
Ramin Golestanian
Keyword(s):  
Critical Role ◽  
Cell Types ◽  
Self Organization ◽  
Biological Processes ◽  
Local Growth ◽  
Agent Based ◽  
Active Processes ◽  
Biofilm Development ◽  
Cellular Aggregates ◽  
By Products

Competition of different species or cell types for limited space is relevant in a variety of biological processes such as biofilm development, tissue morphogenesis and tumor growth. Predicting the outcome for non-adversarial competition of such growing active matter is non-trivial, as it depends on how processes like growth, proliferation and the degradation of cellular matter are regulated in confinement; regulation that happens even in the absence of competition to achieve the dynamic steady state known as homeostasis. Here, we show that passive by-products of the processes maintaining homeostasis can significantly alter fitness. Even for purely pressure-regulated growth and exclusively mechanical interactions, this enables cell types with lower homeostatic pressure to outcompete those with higher homeostatic pressure. We reveal that interfaces play a critical role in the competition: There, growing matter with a higher proportion of active cells can better exploit local growth opportunities that continuously arise as the active processes keep the system out of mechanical equilibrium. We elucidate this effect in a theoretical toy model and test it in an agent-based computational model that includes finite-time mechanical persistence of dead cells and thereby decouples the density of growing cells from the homeostatic pressure. Our results suggest that self-organization of cellular aggregates into active and passive matter can be decisive for competition outcomes and that optimizing the proportion of growing (active) cells can be as important to survival as sensitivity to mechanical cues.

scholarly journals The functions and clinical significance of circRNAs in hematological malignancies

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Xiangxiang Zhou ◽  
Linquan Zhan ◽  
Kai Huang ◽  
Xin Wang
Keyword(s):  
Molecular Mechanisms ◽  
Hematological Malignancies ◽  
Clinical Applications ◽  
Mrna Splicing ◽  
Circular Rnas ◽  
Biological Processes ◽  
The Novel ◽  
Novel Biomarkers ◽  
Regulatory Rnas ◽  
By Products

Abstract With covalently closed circular structures, circular RNAs (circRNAs) were once misinterpreted as by-products of mRNA splicing. Being abundant, stable, highly conserved, and tissue-specific, circRNAs are recently identified as a type of regulatory RNAs. CircRNAs bind to certain miRNAs or proteins to participate in gene transcription and translation. Emerging evidence has indicated that the dysregulation of circRNAs is closely linked to the tumorigenesis and treatment response of hematological malignancies. CircRNAs play critical roles in various biological processes, including tumorigenesis, drug resistance, tumor metabolism, autophagy, pyroptosis, and ferroptosis. The N6-methyladenosine modification of circRNAs and discovery of fusion-circRNAs provide novel insights into the functions of circRNAs. Targeting circRNAs in hematological malignancies will be an attractive treatment strategy. In this review, we systematically summarize recent advances toward the novel functions and molecular mechanisms of circRNAs in hematological malignancies, and highlight the potential clinical applications of circRNAs as novel biomarkers and therapeutic targets for future exploration.

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