Waste Weight Change ( g )
Before After
Residual (%)
Water
Ignition Loss
% %
Inlet Outlet HC Ignition
Oil Water Oil Loss mg / kgdry
% % mg / kgdry
Removal Rate
CLAY 1,000 755 75.5 14.3 7.2 162,000 0.5 1.4 229 99.86 AC 2,001 1,341 67.0 18.6 78.3 3,800 2.2 62.9 170 95.53 CTP 2,002 317 15.8 75.9 34.2 206,000 0.6 14.2 854 99.59 RIB 1,852 186 10.0 29.9 91.8 684,000 0.8 41.7 483 99.93 VGO 3,003 82 2.7 25.0 95.3 874,000 0.3 26.3 201 99.98 Table 2 : Phase 1 pilot results for five hazardous waste samples from MRCSB
% carbonised / treated samples were removed . To determine waste weight reduction , samples were weighed and analysed before and after treatment . One waste sample type was assessed per day using the above cycle .
Results & Analysis
The results for the Phase 1 pilot are shown in Table 2 . In general , CTP sludge , RIB sludge and VGO sludge samples showed significant weight reductions ranging between 84.2 to 97.3 % from the original weight , which corroborated with the high initial oil content ( ranging between 206,000 to 874,000 mg / kg for all types of samples ). Weight reduction for spent clay and spent activated carbon was low due to high mineral contents in both samples . For all samples , the oil removal rates ranged between 95.59 % to 99.98 %, showing very efficient oil removal from all samples . The results for all waste samples were promising . For the study of the residual content of treated waste samples , X-ray fluorescence ( XRF ) was used to assess four of the samples . Significant sulphurs were detected in RIB , VGO and CTP samples ( 17.2 % to 43.8 %), with traces of silica , aluminium and iron detected . No other hazardous substances were detected in all four samples . The conditions of samples before and after carbonisation treatment are shown in Figures 2 and 3 .
The Phase 1 pilot was successfully conducted in December 2022 and the results concluded that oil concentrations for most of the samples were reduced by the carbonisation system at a rate of more than 99 % and the generated offgas could be used to heat the carbonisation kiln , hence reducing the system ’ s energy requirement . This feature will potentially reduce the energy requirement in the next project scale-up , where no additional fuel is needed to energise the system while treating the intended waste . The carbonisation system has also proven that the waste weight reduction of between 84.2 % to 97.3 % of initial weight for high hydrocarbon content wastes was achievable . Based on the initial calculations , it is expected that the cost savings per tonne of waste from the carbonisation system will be significant compared to waste treatment via disposal or other treatments , depending on the quality of wastes and any further treatment required to treat the generated residual . As for activated carbon samples , the treated activated carbon was considered regenerated and can be reused . Further testing will be done in the Phase 2 pilot to validate the conditions of activated carbon samples .
A subsequent Phase 2 pilot was carried out at the MRCSB site until mid-November 2023 , where a bigger carbonisation kiln ( 1700L ) test equipment was used to cater for larger waste loads . After the completion of the Phase 2
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