Biowaste

Modern charcoal retorts are charged with wood, biowaste (bark, sawdust, etc.), peat, and sometimes low-rank coals. Yield and properties (hardness, density, surface area, etc.) can vary widely so the desired end use must be considered. Charcoal from coniferous trees is soft and porous, while that from hardwoods is dense and strong. For barbecuing, charcoal is usually compressed into briquettes, with binders and additives chosen to improve handling and ease of ignition. 

Samples were taken from MSW in district Hai Ba Trung, Hanoi. Waste sources are mainly from households and small street restaurants without separation at source. In this district, waste composition contains high percentage of biowaste which accounts for 55-69%, and plastic and nylon bag are 4-5% and 1.5-2%, respectively [11, 12]. 

Figure 12 presented sample composition of Rl —> R3 for the three barrels with four high-calorific fractions biowaste, nylon bag (plastics), paper, and textile in different ratio. 

For these three barrels, percentage of paper and textile was kept equally, while shares of nylon bag and biowaste were varied. Details of input material are shown in Table 6. 

In this study, volume of leachate was monitored twice a week. Once a week, waste was taken out to mix with air with an expectation of raising microorganism activities to enhance the aerobic condition. High amount of leachate in the next days was noticed. As a result, leachate volume of barrels 1 and 3 was higher but not the case for barrel 2 (Fig. 14). Barrel 2 contained lower content of biowaste, which... 

In the final product, R2 still had higher water content than that in R1 and R3 in spite of in input material this factor of R2 was lower. May think, the percentage of biowaste plays a key role in reducing the water content. Low biowaste content may result in inefficient drying process, but if this component is high, it will cause low quality of RDF. 

The reduction of biowaste content after stabilization time can be identified by the waste composition of input flow (in barrel) and of RDF products of R1 —> R3, which is shown in Fig. 16. 

The higher heating value of R1 —> R3 was calculated based on RDF composition when assuming that only biowaste was degradated and the reduction rate was 60%. 

R1 has the lowest gross heating value of 16.53 MJ/kg which resulted from the low percentage of nylon bag and the high biowaste content from input material. R2 contained the highest percentage of nylon bag thereafter, it received the highest... 

All of the measured data are higher than the calculated data. One of the reasons therefore may be the way of calculation - that it was done when assuming biowaste lost 60% - but in fact, it may lost even more. 

RDF quality is affected by input component, in that, biowaste content accounted for a remarkable parameter. The three parameters - high heating value, water content (WC), and emission factor (EF) - could be better from sample with medium ratio of bio waste to nylon waste (4 1). The higher or lower value of this ratio has not yet given better result. 

Hartlieb et al. [60] In-vessel Municipal biowaste DEHP, pyrene and 86% after... 

Hartlieb N, Ertunc T, Schaeffer A, Klein W (2003) Mineralization, metabolism and formation of non-extractable residues of 14C-labelled organic contaminants during pilot-scale composting of municipal biowaste. Environ Pollut 126 83-91... 

Keywords Agronomic value of composting Anaerobic digestion Biowaste Compost quality Composting process Maturity... 

The collected and treated amounts of organic material differ much in the European Union (EU) countries. Around 35% of the estimated 49 million tons biowaste is presently collected separately (ECN 2008). In Germany, 30% of the household waste insists of biowaste and between 1990 and 2004 the highest increase is also documented for biowaste from two million tons in 1990 to around eight million tons in 2004. The German Federal Compost Quality Assurance Organisation (BGK) assumes the amount in 2007 to 9-10 million tons, but in this year alone six million tons biowastes were delivered to composting plans connected to the BGK. 

In Germany, 60-70% of the biowastes are collected separately and recycled by composting or digestion, but in the EU-15 countries only 6% and 22% are incinerated, and 72% is landfilled (Kehres 2008). For composting the selective collection of waste is important because of the separation of biowaste. 

Furnishing proof and the documents required by the plants to show treatment according to the Biowaste and Fertilizer Ordinance to the regional competent authorities... 

The importance of the composting as biowaste recycling for the sustainable development in Europe can be summarized in the following two points ... 

The increase of the recent years in the biological waste treatment in Europe is reported by ECN (2008). The environmental and market requirements of the biologically treated waste are also reported. The selective biowaste collection the compost production is around 9 million Mg in the European Union. 

The strategies for the management of biowaste in the European Union are summarized by Favoino (2008) as follows ... 

The European Thematic Strategy on Soil Protection 45% of the EU soils are poor in humus and composted biowaste could be a source of organic matter for the soils. 

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