Solid Waste Management Programme for Phitsanulok. Summary Report. Characteristics of Solid Waste after Mechanical Biological Treatment (MBT)

Transcription

1 Solid Waste Management Programme for Phitsanulok Summary Report Characteristics of Solid Waste after Mechanical Biological Treatment (MBT) Environmental Research Centre (ERC) Naresuan University Summary Report: April 200

2 Characteristics of Solid Waste after Mechanical Biological Treatment (MBT) Dr Dondej Tungtakanpoung Environmental Research Centre Naresuan University Phitsanulok, Thailand

3 Introduction In early 999, the Solid Waste Management Project for the Phitsanulok Municipality was started. The main focus of the first phase of the technical assistance project between the Municipality of Phitsanulok and the German Agency for Technical Cooperation (GTZ) ( ) was to develop a model for a sustainable solid waste management system for the city in cooperation with the municipal administration, citizens and the private sector. During this phase all efforts were concentrated on developing a waste management system based on the principles of waste avoidance, reduction, recycling and disposal. Adjustments in the organizational system of the municipality with respect to waste management were also a priority. The main strategic areas for intervention by the project were defined as follows: Improvement of management in the municipality Transfer of technology and know-how Cooperation with the public Involvement of the local private sector and the surrounding cities and communities For landfill management, GTZ produced a feasibility study for application of a mechanical-biological waste treatment process at the Phitsanulok landfill. This study showed the enormous potential of the mechanical biological waste treatment process. At the end of 200, a pilot facility was started as a PPP project (introduction of mechanical biological waste treatment) in co-operation with the city of Phitsanulok and the GTZ Technical Co-operation project. The pilot project was conducted by application of the FABER-AMBRA process type on the landfill in Phitsanulok. It was envisaged to treat 50 % of incoming waste in the landfill. At the beginning of 2005, the Phitsanulok municipality signed a contract with FABER Technology Company Ltd as a consultant for operation of the mechanical biological waste treatment process at the Phitsanulok landfill. The

4 process conducted with the FABER-AMBRA process has been operating successfully. The solid waste after the MBT process has been placed properly in the sanitary landfill. Nevertheless, the filling of solid waste is not the best solution for disposal of the solid waste containing many beneficial materials which could be recycled as Refuse Derived Fuel (RDF) and compost. Therefore, GTZ, FABER Technology Company Ltd and the Phitsanulok municipality agreed to investigate the characteristics of the solid waste after the MBT process for further application. Subsequently, they also contracted the Environmental Research Centre, Naresuan University to conduct an analysis of the solid waste. The result of that study was concluded in April, 200. The MBT Process

5 Material and Method Solid waste maintained in the MBT process for 5 and 9 months was separated into parts: diameter less than 0 mm, between 0 and 40 mm and greater than 40 mm by sieving with a Trommel screen. The sieved products were investigated for composition, physical-chemical characteristics and heat values, as shown in Table. The analysis of the physical-chemical characteristics and heat values was carried out using the methodology described by Standard Methods and ASTM D240, respectively.

6 Table Parameter and Number of Samples Parameter Density Moisture content Total solids Volatile solids Ash content Heavy metals - As - Cr - Cu - Mn - Ni - Cd - Al - Fe - Hg - Pb Carbon Hydrogen Nitrogen ph Heat values (moisture free) Heat value (as collected) Volume Weight Chloride Sulfate 5 month 9 month 9/ 9/2 9/ 5/ 5/2 5/ Total Sample Total

7 Result Waste Composition After the MBT processing of 500 tons of fresh solid waste for 9 months, it was found that the quantity of the solid waste was reduced to 55 tons (4 % reduction). Figure shows that the processed solid waste consists of a diameter lower than 0 mm for 7 tons, between 0 and 40 mm for 9 tons and greater than 40 mm for 42 tons. The composition of the solid waste after the MBT process for 5 and 9 months is shown in Figure 2-4. It can be seen that almost all sieved solid waste with a diameter lower than 0 mm was found to be compost (Figure 5) whereas % of the sieved solid waste with a diameter greater than 40 mm was found to be plastic (Figure ). Quantity of solid waste (tons) Before MBWT > 40 mm 0-40 mm < 0 mm After MBWT for 9 months Figure Quantity of the solid waste before and after MBT process

8 Compost * 00% (a) Compost * 00% (b) Figure 2 The composition of the solid waste with a diameter lower than 0 mm (a) after MBT process for 5 months (b) after MBT process for 9 months

9 Wood 4.2% Plastic.2% Rubber 2.% Metal 2.% Glass 8.5% Textiles.% Foam 0.5% Glazed tiles.8% Compost * 5.5% (a) Foam 0.7% Textiles 0.% Wood 5.7% Plastic 5.2% Metal 2.9% Glazed tiles.4% Paper 0.9% Compost* 0.% Glass.% Figure The composition of the solid waste with a diameter of 0 to 40 mm (a) after MBT process for 5 months (b) after MBT process for 9 months (b)

10 Foam.9% Textiles.2% wood.5% Metal 2.0% Compost*.4% plastic 72.0% (a) Metal.8% Foam.0% Compost* 7.2% Wood 9.8% Plastic 80.0% Figure 4 The composition of the solid waste with a diameter greater than 40 mm (a) after MBT process for 5 months (b) after MBT process for 9 months (b)

11 Figure 5 Solid waste with a diameter lower than 0 mm after MBT process Figure Solid waste with a diameter greater than 40 mm after MBT process

12 Physical and Chemical Characteristics The physical and chemical characteristics of the solid waste after the MBT process for 5 and 9 months is shown in Table 2. It would seem that the characteristics of the solid wastes after the MBT process for 5 months are about the same as that for 9 months. The C/N ratio of the sieved product with a diameter less than 0 mm is 8/ for 5 month old MBT and 2/ for 9 month old MBT. Therefore, the sieved product diameter less than 0 mm may be considered to be compost identified by The Thai Agricultural Commodity and Food Standard TACFS However, heavy metal composition in the compost has to meet the Standard (see Table ). The density and organic carbon of solid waste with a diameter more than 40 mm is lower than that of solid waste with a diameter lower than 40 mm because most of it is plastic (Figure 4). Therefore, it could be developed for Refuse Derived Fuel (RDF). Table 2 Characteristics of the solid waste after MBT process for 5 and 9 months Parameter 5 months MBT 9 months MBT 0 mm - < 0 mm 40 mm > 20 mm < 0 mm 0 mm - 40 mm > 20 mm Density (kg/m) Moisture content (%) Total solids (mg/g) Volatile Solids (mg/g) Ash Content (mg/g) Organic Carbon (mg/g) Hydrogen (mg/g) Nitrogen (mg/g) ph Chloride (mg/g) Sulfate (mg/g) Heavy Metals

13 The heavy metals concentration of the solid waste after the MBT process for 5 and 9 months is shown in Table. It can be seen from the Table that the concentration of heavy metals in the solid waste is lower than the standard values limit in compost except for arsenic. The concentration of aluminum exhibited an excessive quantity in the solid waste. Therefore, the use of the solid waste as compost after MBT would be possible by reducing the heavy metals concentration in the solid waste. Alternatively, the solid waste after the MBT process with a diameter lower than 0 mm and between 0 and 40 mm could be reused as a bio-filter to cover the MBT pile owing to the extreme concentration of some heavy metals. Table Heavy metals concentration in the solid waste after MBT process for 5 and 9 months Parameter 5 month MBT 9 month MBT Value Limits < 0 mm 0 mm - 40 mm > 20 mm < 0 mm 0 mm - 40 mm > 20 mm in Compost As (mg/kg) < 50 (Thailand) Cr (mg/kg) < 00 (Thailand) Fe (mg/kg) Al (mg/kg) Hg (mg/kg). 0. ND < 2 (Thailand) Cu (mg/kg) < 500 (Thailand) Mn (mg/kg) < 200(Australia ) Ni (mg/kg) ND ND ND ND ND ND < 50 (EEC) Cd (mg/kg) ND ND ND ND < 5 (Thailand) Pb (mg/kg) < 500 (Thailand)

14 Heat values The heat values of the solid waste after the MBT process for 5 and 9 months is shown in Table 4. It can be seen that the heat values of the solid waste with a diameter greater than 40 mm is higher than the waste with a diameter lower than 0 mm and between 0 and 40 mm. It is approximately the same as the heat value of diesel fuel. On this basis, it is almost certain that the solid waste with a diameter greater than 40 mm can be developed into Refuse Derived Fuel (RDF). Table 4 Heat values of the solid waste after MBT process for 5 and 9 months Parameter 5 month MBT 9 month MBT < 0 mm 0 mm - 40 mm > 20 mm < 0 mm 0 mm - 40 mm > 20 mm Heat values (J/g) As collected Moisture free

15 Conclusion The separation of solid waste after the MBT process into parts: diameter lower than 0 mm, between 0 and 40 mm and greater than 40 mm was found to be an effective classification for the reuse of the materials. The characteristics of the solid waste after the MBT process for 5 months were found to be nearly the same as that for 9 months. The solid waste after the MBT process with a diameter lower than 0 mm was found to have the potential for development to be compost. However, arsenic in the solid waste was greater than the standard limits in compost. Therefore, the solid waste would have to be modified by reducing the heavy metals concentration before using as compost. The solid waste after the MBT process with a diameter of 0 and 40 mm was found to have the potential for reuse as a bio-filter to cover the MBT pile. The solid waste after the MBT process with a diameter greater than 40 mm was found to have outstanding heat values. Consequently, the potential for developing the biggest-size MBT solid wastes as Refuse Derived Fuel (RDF) appears to be quite high. The MBT process could be maintained for about 5 months because the heat values of the solid waste after the MBT process for 5 and 9 months were not very different. The heat values of the dried solid waste after the MBT process were found to be the same as that of the fresh solid waste. As a result, the drying process is not necessary for pretreatment of the solid wastes before reusing as Refuse Derived Fuel (RDF).