Applicability of the Forchheimer Equation to Forced-Aeration Windrow Composting: Variation of Airflow Characteristics with Humidity and Volatile Solids

2012 ◽  
Vol 39 (2) ◽  
pp. 149-159 ◽  
Author(s):  
Pedro Almeida ◽  
Ana Silveira ◽  
Antonio Ferreira Miguel
Keyword(s):  
Forchheimer Equation ◽  
Volatile Solids ◽  
Forced Aeration ◽  
Windrow Composting

Windrow composting of wastewater biosolids: process performance and product stability assessment

2000 ◽  
Vol 42 (9) ◽  
pp. 217-226 ◽  
Author(s):  
K. E. Lasaridi ◽  
E. I. Stentiford ◽  
T. Evans
Keyword(s):  
Process Performance ◽  
Stability Assessment ◽  
Stability Parameters ◽  
Compost Stability ◽  
Volatile Solids ◽  
Composting Facility ◽  
Two Parameters ◽  
Windrow Composting ◽  
Potential Stability ◽  
Ambient Levels

The composting process at the Thames Water composting facility at Little Marlow, Buckinghamshire, UK, was monitored in order to access the value of both process parameters (temperature, drying tendency) and compost stability indicators (VS, COD, respiration rate) for process performance evaluation. A simple model was developed to describe the process rate on the basis of volatile solids and respirometric results. Pile core temperature exceeded 55°C in the first 2-3 days and reached ambient levels after 8-10 weeks. Compost stability, as determined by both wet (SOUR) and dry (DSOUR) respirometry increased with age, the two parameters correlating well with each other and composting time. The SOUR dropped from about 20 mg/g VS/hr for the fresh compost to 5 mg/g VS/hr at the end of the 4 weeks of turning and to 1.5 mg/g VS/hr after five months of maturation. The COD, optical density at 665, 465 and 280 nm, and the E4/E6 ratio of water extracts were also analysed as potential stability parameters, but the information revealed was limited.

scholarly journals Effect of passive and forced aeration on composting of market solid waste

2020 ◽  
Vol 9 (1) ◽  
pp. 182
Author(s):  
M. Atauzzaman ◽  
Q. H. Bari
Keyword(s):  
Solid Waste ◽  
Total Sample ◽  
Bulking Agent ◽  
Percentage Reduction ◽  
Vegetable Waste ◽  
Volatile Solids ◽  
Before And After ◽  
Waste Mixture ◽  
Forced Aeration ◽  
Daily Time

This study aimed to determine the effect of passive and forced aeration on composting of market wastes. Suitable vegetable waste, waste paper and sawdust as bulking agent were mixed with the proportion 75:10:15. Temperature inside composting reactors was measured daily time to time. Total sample and volatile solids were determined before and after composting of waste mixture with both passive and forced aeration. Temperature increased to maximum 52 ºC for passive aeration and 54 ºC for forced aeration. The percentage reduction in total sample was found to be greater for forced aeration than passive aeration. The volatile solids decreased with time at the end of both processes. The extent of volatile solids degradation of waste mixture with time was determined through forced aeration for a series of composting process. Total sample and volatile solids were determined at 2, 3 or 4 days interval. The percentage reductions in total    sample and volatile solids were found to be varied from 3 to 68 % and 4 to 55% respectively. The percentage reduction in volatile solids increased with time. There is a possibility of recycling the waste mixture in the form of composting.  

Greenhouse gas emission from covered windrow composting with controlled ventilation

2011 ◽  
Vol 30 (2) ◽  
pp. 155-160 ◽  
Author(s):  
Evgheni Ermolaev ◽  
Mikael Pell ◽  
Sven Smårs ◽  
Cecilia Sundberg ◽  
Håkan Jönsson
Keyword(s):  
Municipal Solid Waste ◽  
Greenhouse Gas ◽  
Solid Waste ◽  
Greenhouse Gas Emission ◽  
Ghg Emissions ◽  
Control Schemes ◽  
Ambient Concentrations ◽  
Forced Aeration ◽  
Set Up ◽  
Windrow Composting

Data on greenhouse gas (GHG) emissions from full-scale composting of municipal solid waste, investigating the effects of process temperature and aeration combinations, is scarce. Oxygen availability affects the composition of gases emitted during composting. In the present study, two experiments with three covered windrows were set up, treating a mixture of source separated biodegradable municipal solid waste (MSW) fractions from Uppsala, Sweden, and structural amendment (woodchips, garden waste and re-used compost) in the volume proportion 1:2. The effects of different aeration and temperature settings on the emission of methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2) during windrow composting with forced aeration following three different control schemes were studied. For one windrow, the controller was set to keep the temperature below 40 °C until the pH increased, another windrow had minimal aeration at the beginning of the process and the third one had constant aeration. In the first experiment, CH4 concentrations (CH4:CO2 ratio) increased, from around 0.1% initially to between 1 and 2% in all windrows. In the second experiment, the initial concentrations of CH4 displayed similar patterns of increase between windrows until day 12, when concentration peaked at 3 and 6%, respectively, in two of the windrows. In general, the N2O fluxes remained low (0.46 ± 0.02 ppm) in the experiments and were two to three times the ambient concentrations. In conclusion, the emissions of CH4 and N2O were low regardless of the amount of ventilation. The data indicates a need to perform longer experiments in order to observe further emission dynamics.

ENHANCED BIODEGRADATION OF OIL

1985 ◽  
Vol 1985 (1) ◽  
pp. 531-537 ◽  
Author(s):  
Gerd Halmö
Keyword(s):  
Water Soluble ◽  
Oil Degradation ◽  
Optimal Conditions ◽  
Oil Emulsion ◽  
Enhanced Biodegradation ◽  
Soluble Fertilizer ◽  
Forced Aeration ◽  
One Year ◽  
Leachate Quality ◽  
Windrow Composting

ABSTRACT In a study of biodegradation of a weathered crude oil emulsion, direct addition of fertilizers to oil on shore enhanced the natural biodegradation. An oil-soluble urea fertilizer was at least as efficient as a water-soluble one containing ammonia and nitrate. In one year, the paraffins were totally degraded. Composting was studied both in aerated full-scale windrows and in model columns. Oily seaweed was mixed and composted with different oil sorbents and fertilizers to find the optimal conditions for oil degradation. The best alternative was obtained by mixing the oily seaweed with pine bark and a nutrient of urea in a microemulsion of oleic acid. Windrow composting of this mixture, with forced aeration from the bottom, resulted in approximately 65 percent degradation of the paraffins within a summer season, 70 percent over the entire year. The oil-soluble fertilizer was better retained in the windrows than the water-soluble one tried earlier, thus improving the leachate quality. Revegetation on this compost was successful.

Windrow composting as an effective method to dispose of large numbers of fish

1998 ◽  
Author(s):  
L.C.I. Tabb ◽  
C.E. Starliper ◽  
E.B. Shotts ◽  
J. Everson ◽  
A.W. Palmisano
Keyword(s):  
Large Numbers ◽  
Windrow Composting

Deep Shaft High Rate Aerobic Digestion: Laboratory and Pilot Plant Performance

1981 ◽  
Vol 16 (1) ◽  
pp. 71-90 ◽  
Author(s):  
F. Tran ◽  
D. Gannon
Keyword(s):  
Retention Time ◽  
Oxygen Transfer ◽  
Pilot Plant ◽  
High Rate ◽  
Plant Performance ◽  
High Solids ◽  
Aerobic Digestion ◽  
Volatile Solids ◽  
Solids Content ◽  
High Solids Content

Abstract The Deep Shaft process, originating from ICI Ltd. in the U.K., has been further developed by C-I-L Inc., Eco-Technology Division into an extremely energy efficient, high rate biological treatment process for industrial and municipal wastewaters. The Deep Shaft is essentially an air-lift reactor, sunk deep in the ground (100 - 160 m): the resulting high hydrostatic pressure together with very efficient mixing in the shaft provide extremely high oxygen transfer efficiencies (O.T.E.) of up to 90% vs 4 to 20% in other aerators. This high O.T.E. suggests real potential for Deep Shaft technology in the aerobic digestion of sludges and animal wastes: with conventional aerobic digesters an O.T.E. over 8% is extremely difficult to achieve. This paper describes laboratory and pilot plant Deep Shaft aerobic digester (DSAD) studies carried out at Eco-Research's Pointe Claire, Quebec laboratories, and at the Paris, Ontario pilot Deep Shaft digester. An economic pre-evaluation indicated that DSAD had the greatest potential for treating high solids content primary or secondary sludge (3-7% total solids) in the high mesophilic and thermophilic temperature range (25-60°C) i.e. in cases where conventional digesters would experience severe limitations of oxygen transfer. Laboratory and pilot plant studies have accordingly concentrated on high solids content sludge digestion as a function of temperature. Laboratory scale daily draw and fill DSAD runs with a 5% solids sludge at 33°C with a 3 day retention time have achieved 34% volatile solids reduction and a stabilized sludge exhibiting a specific oxygen uptake rate (S.O.U.R.) of less than 1 mgO2/gVSS/hour, measured at 20°C. This digestion rate is about four times faster than the best conventional digesters. Using Eco-Research's Paris, Ontario pilot scale DSAD (a 160 m deep 8 cm diameter u-tube), a 40% reduction in total volatile solids, (or 73% reduction of biodegradable VS) and a final SOUR of 1.2 mg02/gVSS/hour have been achieved for a 4.6% solids sludge in 4 days at 33°C, with loading rates of up to 7.9 kg VSS/m3-day. Laboratory runs at thermophilic temperatures (up to 60°C) have demonstrated that a stabilized sludge (24-41% VSS reduction) can be produced in retention time of 2 days or less, with a resulting loading rate exceeding 10 kg VSS/m3-day.

Activated Sludge Exocellular Material Extraction Methods and Problems

1974 ◽  
Vol 9 (1) ◽  
pp. 250-261
Author(s):  
D.F. Carr ◽  
J. Ganczarczyk
Keyword(s):  
Activated Sludge ◽  
High Speed ◽  
Sewage Treatment ◽  
Dry Weight ◽  
Extraction Methods ◽  
Volatile Material ◽  
Bacterial Cultures ◽  
Volatile Solids ◽  
Pure Bacterial Cultures ◽  
Material Extraction

Abstract Activated sludge samples from two Toronto sewage treatment plants were subjected to the extraction of exocellular material by means of 9 different methods suggested for this purpose. Some of those methods, originally developed for pure bacterial cultures, were modified for the application to activated sludge. The amount of exocellular material obtained varied for Lakeview sludges from 0.4 to 3.2% of their dry volatile solids, and for Humber sludges from 0.3 to 5.3%. It has been found that extractions by the use of sulphuric acid, high-speed centrifugation and sodium hydroxide, were not suitable for the studied material. Especially surprising was the ineffectiveness of high-speed centrifugation to yield any measurable amounts of extract. The boiling water extraction is recommended for further studies on activated sludge exocellular material. The material extracted from activated sludge is very complex in nature. Generally more polysaccharide than protein was extracted, but the remaining volatile material may form up to 70% of the dry weight.

Comparison of Aerobic and Anoxic-Aerobic Digestion of Waste Activated Sludge

1985 ◽  
Vol 17 (8) ◽  
pp. 1475-1478 ◽  
Author(s):  
A P. C. Warner ◽  
G. A. Ekama ◽  
G v. R. Marais
Keyword(s):  
Experimental Data ◽  
Activated Sludge ◽  
Waste Activated Sludge ◽  
Activated Sludge Process ◽  
Cycle Times ◽  
Waste Sludge ◽  
Volatile Solids ◽  
In Series ◽  
Flow Through ◽  
Theoretical Simulations

The laboratory scale experimental investigation comprised a 6 day sludge age activated sludge process, the waste sludge of which was fed to a number of digesters operated as follows: single reactor flow through digesters at 4 or 6 days sludge age, under aerobic and anoxic-aerobic conditions (with 1,5 and 4 h cycle times) and 3-in-series flow through aerobic digesters each at 4 days sludge age; all digesters were fed draw-and-fill wise once per day. The general kinetic model for the aerobic activated sludge process set out by Dold et al., (1980) and extended to the anoxic-aerobic process by van Haandel et al., (1981) simulated accurately all the experimental data (Figs 1 to 4) without the need for adjusting the kinetic constants. Both theoretical simulations and experimental data indicate that (i) the rate of volatile solids destruction is not affected by the incorporation of anoxic cycles and (ii) the specific denitrification rate is independent of sludge age and is K4T = 0,046(l,029)(T-20) mgNO3-N/(mg active VSS. d) i.e. about 2/3 of that in the secondary anoxic of the single sludge activated sludge stystem. An important consequence of (i) and (ii) above is that denitrification can be integrated easily in the steady state digester model of Marais and Ekama (1976) and used for design (Warner et al., 1983).

Estimation of Energy Saving for Melting Process on Sewage Sludge

1991 ◽  
Vol 23 (10-12) ◽  
pp. 2011-2018 ◽  
Author(s):  
T. Murakami ◽  
K. Sasabe ◽  
K. Sasaki ◽  
T. Kawashima
Keyword(s):  
Sewage Sludge ◽  
Moisture Content ◽  
Energy Saving ◽  
Fuel Consumption ◽  
Melting Process ◽  
System Operation ◽  
Operational Conditions ◽  
Volatile Solids ◽  
Cake Moisture ◽  
Very High

The possible volume reduction and stabilization of the sewage sludge associated with the melting process are expected to be greater than with the incineration process. In addition, melted slag can be utilized. However, since the melting process requires a very high temperature to melt inorganics (ash) in the sludge, the technologies to minimize energy consumption, to establish system operation and to prolong durability of facilities should be developed. This paper discusses the auxiliary fuel consumption as follows.(1)Preparation of a model that provides the auxiliary fuel consumption of the melting system on the basis of the mass and heat balances.(2)Evaluation of the auxiliary fuel consumption in the above model using the cake moisture content, the volatile solids of the cake, the dried cake moisture content and the melting temperature as parameters.(3)Examination of the operational conditions for an energy saving melting system based on the results of (1) and (2) above.

Sign in / Sign up

Export Citation Format

Share Document