Search results for "WASTE TREATMENT"
showing 10 items of 72 documents
Biological nitrogen removal from municipal landfill leachate: low-cost nitrification in biofilters and laboratory scale in-situ denitrification.
2002
The slow leaching of nitrogen from solid waste in landfills, resulting in high concentrations of ammonia in the landfill leachate, may last for several decades. The removal of nitrogen from leachate is desirable as nitrogen can trigger eutrophication in lakes and rivers. In the present study, a low-cost nitrification-denitrification process was developed to reduce nitrogen load especially in leachates from small landfills. Nitrification was studied in laboratory and on-site pilot aerobic biofilters with waste materials as filter media (crushed brick in upflow filters and bulking agent of compost in a downflow filter) while denitrification was studied in a laboratory anoxic/anaerobic column …
Anaerobic on-site black water and kitchen waste treatment using UASB-septic tanks at low temperatures.
2006
Anaerobic on-site treatment of black water (BW) and a mixture of black water and kitchen waste (BWKW) was studied in a two-phased upflow anaerobic sludge blanket septic tank (UASBst) at 10–20 °C. The processes were fed either continuously or discontinuously (twice per weekday). Moreover, BWKW was post-treated for nitrogen removal in an intermittently aerated moving bed biofilm reactor (MBBR) at 20 °C. Removal of total chemical oxygen demand (CODt) was efficient at minimum 90% with all three UASBst at all temperatures. Removal of dissolved COD (CODdis) was also high at approx. 70% with continuously fed BW and discontinuously fed BWKW, while with discontinuous BW feeding it was 20%. Temperatu…
Nitrification of anaerobically pretreated municipal landfill leachate at low temperature
2000
Abstract Nitrification of anaerobically pretreated municipal landfill leachate (270–1000 mg COD l −1 , 53–270 mg NH 4 –N l −1 ) was studied in laboratory-scale activated sludge reactors without (AS) and with (ASC) the addition of plastic carrier material. The reactors were run at 10°C (149 d), 7°C (21 d) and 5°C (16 d). With a loading rate of 0.027 g NH 4 –N g MLVSS −1 d −1 and a hydraulic retention time of ca. 3 d, at 10°C, complete nitrification was obtained in both reactors. At 7°C, and in loading rate of 0.023 g NH 4 –N g MLVSS −1 d −1 , both reactors appeared to be overloaded and ammonium removal was only ca. 93%. At 5°C, with a lower loading rate of 0.010 g NH 4 –N g MLVSS −1 d −1 …
Semi-continuous anaerobic digestion of solid poultry slaughterhouse waste: effect of hydraulic retention time and loading.
2002
Abstract We studied the effect of hydraulic retention time (HRT) and loading on anaerobic digestion of poultry slaughterhouse wastes, using semi-continuously fed, laboratory-scale digesters at 31°C. The effect on process performance was highly significant: Anaerobic digestion appeared feasible with a loading of up to 0.8 kg volatile solids (VS)/m 3 d and an HRT of 50–100 days. The specific methane yield was high, from 0.52 to 0.55 m 3 /kg VS added . On the other hand, at a higher loading, in the range from 1.0 to 2.1 kg VS/m 3 d, and a shorter HRT, in the range from 25 to 13 days, the process appeared inhibited and/or overloaded, as indicated by the accumulation of volatile fatty acids an…
Methane oxidation in a boreal climate in an experimental landfill cover composed from mechanically–biologically treated waste
2007
The present study evaluated microbial methane (CH4) oxidation in a boreally located outdoor landfill lysimeter (volume 112 m3, height 3.9 m) filled with mechanically-biologically treated waste (MBT residual) and containing a cover layer made from the same MBT residual. The calculations based on gas emission and pore gas measurements showed that, between April and October 2005, a significant proportion (96%) of the methane produced (23 l CH4 m(-2) d(-1)) in the lysimeter was oxidized. Methane was oxidized mainly at the depths of 35-75 cm, as indicated by the upward decrease both in the methane concentration and in the methane-to-carbon dioxide ratio in the pore gas. Lower methane oxidation (…
Performance in the treatment of municipal waste: Are European Union member states so different?
2019
Abstract Efficient management and treatment of municipal waste is essential for achieving green growth. Recent studies have revealed convergence in European Union (EU) member states' performance in municipal waste treatment, particularly since the transposition of the 2008 European Waste Framework Directive into national laws. However, there are still notable differences between countries. In this paper, we calculate a composite indicator of performance in municipal waste treatment at the country-level. We also present an in-depth examination of differences in performance across EU member states. Our results show that the best performers—mainly high income Northern and Central European coun…
Windrow composting of source separated kitchen biowastes in Finland
2000
All households in the City of Jyväskylä have been required to source-separate their wastes since June 1996. The accumulation of kitchen biowaste was about 60 kg per resident in 1997, with an efficiency of more than 75%. The residents of almost 50% of the detached houses in the city opted for small-scale composting. Ensuing kitchen biowaste was surprisingly pure: the estimated content of non-compostable material was less than 0.1 % by weight. The biowastes were composted at the Mustankorkea waste station in open windrows. Adequate aeration of the windrows was guaranteed when the initial height of the windrow was less than 1.5 m and the blending ratio for biowaste and bulking agent was one t…
Reliable method for assessing the COD mass balance of a submerged anaerobic membrane bioreactor (SAMBR) treating sulphate-rich municipal wastewater
2012
The anaerobic treatment of sulphate-rich wastewater causes sulphate reducing bacteria (SRB) and methanogenic archaea (MA) to compete for the available substrate. The outcome is lower methane yield coefficient and, therefore, a reduction in the energy recovery potential of the anaerobic treatment. Moreover, in order to assess the overall chemical oxygen demand (COD) balance, it is necessary to determine how much dissolved CH4 is lost in the effluent. The aim of this study is to develop a detailed and reliable method for assessing the COD mass balance and, thereby, to establish a more precise methane yield coefficient for anaerobic systems treating sulphate-rich wastewaters. A submerged anaer…
Biological Nutrient Removal and Fouling Phenomena in a University of Cape Town Membrane Bioreactor Treating High Nitrogen Loads
2013
The behavior of a University of Cape Town (UCT) membrane bioreactor (MBR) system was investigated for use in biological nutrient removal from real wastewater. The pilot plant was in operation for a period of 165 days, during which an extensive data gathering campaign was conducted. The pilot plant was started up by inoculating it with activated sludge from a nearby wastewater treatment plant, and it was fed by real municipal wastewater characterized by high organic nitrogen concentrations attributable to discharges from industrial wastewater and sporadic landfill leachate. Carbon and biological nutrient removal processes, a sludge production process, and a membrane fouling mechanism were an…
Two-stage anaerobic digestion of tomato, cucumber, common reed and grass silage in leach-bed reactors and upflow anaerobic sludge blanket reactors
2010
Abstract Anaerobic digestion of tomato, cucumber, common reed and grass silage was studied in four separate two-stage reactor configuration consisting of leach bed reactor (LBR) and upflow anaerobic sludge blanket reactor (UASB). LBR studies showed that COD solubilization for cucumber and grass silage was higher (50%) than tomato (35%) and common reed (15%). Results also showed that 31–39% of initial TKN present in tomato and cucumber was solubilized in the leachates and 47–54% of the solubilized TKN was converted to NH4-N. The corresponding values for common reed and grass silage were 38–50% and 18–36%, respectively. Biomethanation of the leachates in UASB reactors resulted in methane yiel…