Search results for "WASTE TREATMENT"

A Tool for Energy Management and Cost Assessment of Pumps in Waste Water Treatment Plants

2017

Waste Water Treatment Plants (WWTPs) are generally considered energy intensive. Substantial energy saving potentials have been identified by several authors. Pumps consume around 12% of the overall WWTP energy consumption. In this paper we propose a methodology that uses the sensors commonly installed in WWTPs, such as volume and energy sensors, to perform energy benchmarking on pumps. The relationship between energy efficiency and flow rate is used to detect specific problems, and potential solutions are proposed, taking into consideration economical and environmental criteria (cost of externalities in energy production). The methodology integrates energy benchmarking, data-mining, and eco…

Landfill Culture: Some Implications to Degrowth

2016

To some extent, waste is just one more sign of the unsustainability of growth. Waste from industrial and socio-economic metabolism must be understood as any unusable material left over after a job, function or operation has been completed, which however, retains the ability to disrupt natural systems and interfere with them as one of its inherent properties. As part of such waste, Municipal Solid Waste (MSW) represents the unusable (or underused) and rejected fraction of the material resources mobilized by the sophisticated urban and/or industrial ecosystem. Although the volume of MSW is relatively small compared to other waste types, it is increasingly important as a result of its steady r…

Municipal Solid Waste Management in the Accra Metropolitan Area, Ghana

2003

Municipal solid waste management in Accra, Ghana, is at present delivered in an unsustainable manner. Due to uncontrolled urbanisation, large quantities of waste are generated daily in Accra, and this exerts much pressure on an over strained solid waste management system. Coupled with weak institutional capacity, and lack of resources, both human and capital, the city authorities face difficulties in ensuring that all the waste generated in the city is collected for disposal. Home collection of waste is limited to high and, some middle income areas while the poor are left to contend with the problem on their own. This leads to indiscriminate disposal of waste in surface drains, canals and s…

Healthcare Waste Treatment by Microwave: Critical Parameters and Future Perspectives

2019

Modelling hydrolysis: Simultaneous versus sequential biodegradation of the hydrolysable fractions

2018

Hydrolysis is considered the limiting step during solid waste anaerobic digestion (including co-digestion of sludge and biosolids). Mechanisms of hydrolysis are mechanistically not well understood with detrimental impact on model predictive capability. The common approach to multiple substrates is to consider simultaneous degradation of the substrates. This may not have the capacity to separate the different kinetics. Sequential degradation of substrates is theoretically supported by microbial capacity and the composite nature of substrates (bioaccessibility concept). However, this has not been experimentally assessed. Sequential chemical fractionation has been successfully used to define i…

Trace compounds of biogas from different biogas production plants

2007

Biogas composition and variation in three different biogas production plants were studied to provide information pertaining to its potential use as biofuel. Methane, carbon dioxide, oxygen, nitrogen, volatile organic compounds (VOCs) and sulphur compounds were measured in samples of biogases from a landfill, sewage treatment plant sludge digester and farm biogas plant. Methane content ranged from 48% to 65%, carbon dioxide from 36% to 41% and nitrogen from <1% to 17%. Oxygen content in all three gases was <1%. The highest methane content occurred in the gas from the sewage digester while the lowest methane and highest nitrogen contents were found in the landfill gas during winter. The amoun…

Occupational hygiene in a Finnish drum composting plant

2005

Bioaerosols (microbes, dust and endotoxins) and volatile organic compounds (VOCs) were determined in the working air of a drum composting plant treating source-separated catering waste. Different composting activities at the Oulu drum composting plant take place in their own units separated by modular design and constructions. Important implication of this is that the control room is a relatively clean working environment and the risk of exposure to harmful factors is low. However, the number of viable airborne microbes was high both in the biowaste receiving hall and in the drum composting hall. The concentration (geometric average) of total microbes was 21.8 million pcs/m3 in the biowaste…

Microbial Fuel Cell with Ni–Co Cathode Powered with Yeast Wastewater

2018

Wastewater originating from the yeast industry is characterized by high concentration of pollutants that need to be reduced before the sludge can be applied, for instance, for fertilization of croplands. As a result of the special requirements associated with the characteristics of this production, huge amounts of wastewater are generated. A microbial fuel cell (MFC) forms a device that can apply wastewater as a fuel. MFC is capable of performing two functions at the same time: wastewater treatment and electricity production. The function of MFC is the production of electricity during bacterial digestion (wastewater treatment). This paper analyzes the possibility of applying yeast wastewate…

Correlation of wood-based components and dewatering properties of waste activated sludge from pulp and paper industry.

2010

Large amounts of wet sludge are produced annually in municipal and industrial wastewater treatment. Already in pulp and paper industry, more than ten million tons of primary sludge, waste activated sludge, and de-inking sludge is generated. Waste activated sludge contains large quantities of bound water, which is difficult to dewater. Low water content would be a matter of high calorific value in incineration but it also has effects on the volume and the quality of the matter to be handled in sludge disposal. In this research waste activated sludges from different pulp and paper mills were chemically characterised and dewatered. Correlations of chemical composition and dewatering properties…

Pyrolysis of humic acids from digested and composted sewage sludge

2000

Humic acids (HAs) were extracted from four digested sewage sludge samples composted for four months, one, two and four years. HAs were pyrolyzed at three different temperatures applying both conventional and in situ methylation (ISM) pyrolysis. The pyrolysates were analyzed using gas chromatography-mass spectrometry (GC/MS). Derivatization (ISM) and pyrolysis temperature had dramatic effects on the composition and relative amounts of the pyrolysates. Among the derivatized HA fragments aliphatic compounds prevailed under all the pyrolysis conditions tested. Aromatic substances consisting mainly of guaiacyl-type compounds were detected in higher abundances only at elevated temperatures. Witho…