An innovative in-situ stabilisation treatment followed by ex-situ sediment composting was tested for its ability to treat and dispose of heavy-metal-polluted sediments in a river near the Chinese Pearl Delta. First, p...An innovative in-situ stabilisation treatment followed by ex-situ sediment composting was tested for its ability to treat and dispose of heavy-metal-polluted sediments in a river near the Chinese Pearl Delta. First, polluted sediments were treated in-situ to stabilise the heavy metals. Then the treated sediments were dredged, dewatered and sent for high temperature aerobic composting （HTAC） treatment. Finally, the compost products were used as a fertiliser for fiver bank plants. The stabilisation efficiency of heavy metals during the process was investigated and the results are as follows： （1） using in-situ stabilisation, the extraction concentrations of Cu, Zn and Pb were reduced by 65.0%, 82.2% and 90.0%, respectively, which are much lower than the national standard given in the Identification Standard for Hazardous Waste （GB5085.3-1996）; （2） chemical fraction analysis showed that heavy metals were further stabilized during the HTAC treatment; （3） the concentrations of Cu, Zn and Pb in rainwater leachate through the river bank met the level of class V in the Environmental Quality Standards for Surface Water in China （GB3838-2002）. Therefore, using this new process, the toxicities of heavy metals in sediments were reduced markedly.展开更多
Whereas the pulp and paper industrial sector—considered the second highest consumer of freshwater in Europe—has already been provided with sufficient wastewater characterization and treatment technologies, other woo...Whereas the pulp and paper industrial sector—considered the second highest consumer of freshwater in Europe—has already been provided with sufficient wastewater characterization and treatment technologies, other wood-based industries (e.g. furniture, floor production), which do not use water for manufacturing processes, generate different wastewater streams after: 1) cleaning/washing of machinery that applies adhesives and coatings onto wood surfaces;2) cleaning/washing of machinery that applies specific products for the curing phase of adhesives;3) cleaning/washing of sharp planar blades used for the sawn process and to prepare wood surfaces for the adhesive application;4) cleaning/washing of the floor;5) cleaning/washing of trucks and vehicles. The dilution of low-volumes of highly polluted wastewater is not acceptable any longer since conventional treatment plants are not designed for these types of industrial wastewater. There is a need for proper characterization, treatability studies, designing and testing alternative small size and cost-effective treatment systems for on-site implementation. Treatment systems based on sorption mechanisms are flexible, easy to operate and generate less sludge and several low-cost sorbents generated by forestry activities have advantageous physico-chemical characteristics. The current paper presents the preliminary results from a pilot treatment system consisting of an equalization tank, settling/sedimentation and two sorption reactors in parallel using Pinus sylvestris sawdust as sorbent implemented as part of an integrated water management plan in a wood-floor industry. The simple to operate and cost-effective pilot treatment system performs satisfactorily during an initial period of operation. The study shows an average 39% - 54% reduction of TPH;17% - 38% reduction of oil;2% - 15% of reduction of COD and;11% - 74% reduction of most toxic metals but for Co, Ni and Zn in the system B. Based on these results, Pinus sylvestris sawdust is a potential low-cost and abundant material to be considered for industrial wastewater treatment plants.展开更多
基金supported by the Scientific and Tech- nological Planning Project of Guangdong Province (No. 2003A3040404)the Guangdong & Hong Kong Tech- nology Cooperation Funding (No. 2006A36702001)
文摘An innovative in-situ stabilisation treatment followed by ex-situ sediment composting was tested for its ability to treat and dispose of heavy-metal-polluted sediments in a river near the Chinese Pearl Delta. First, polluted sediments were treated in-situ to stabilise the heavy metals. Then the treated sediments were dredged, dewatered and sent for high temperature aerobic composting （HTAC） treatment. Finally, the compost products were used as a fertiliser for fiver bank plants. The stabilisation efficiency of heavy metals during the process was investigated and the results are as follows： （1） using in-situ stabilisation, the extraction concentrations of Cu, Zn and Pb were reduced by 65.0%, 82.2% and 90.0%, respectively, which are much lower than the national standard given in the Identification Standard for Hazardous Waste （GB5085.3-1996）; （2） chemical fraction analysis showed that heavy metals were further stabilized during the HTAC treatment; （3） the concentrations of Cu, Zn and Pb in rainwater leachate through the river bank met the level of class V in the Environmental Quality Standards for Surface Water in China （GB3838-2002）. Therefore, using this new process, the toxicities of heavy metals in sediments were reduced markedly.
文摘Whereas the pulp and paper industrial sector—considered the second highest consumer of freshwater in Europe—has already been provided with sufficient wastewater characterization and treatment technologies, other wood-based industries (e.g. furniture, floor production), which do not use water for manufacturing processes, generate different wastewater streams after: 1) cleaning/washing of machinery that applies adhesives and coatings onto wood surfaces;2) cleaning/washing of machinery that applies specific products for the curing phase of adhesives;3) cleaning/washing of sharp planar blades used for the sawn process and to prepare wood surfaces for the adhesive application;4) cleaning/washing of the floor;5) cleaning/washing of trucks and vehicles. The dilution of low-volumes of highly polluted wastewater is not acceptable any longer since conventional treatment plants are not designed for these types of industrial wastewater. There is a need for proper characterization, treatability studies, designing and testing alternative small size and cost-effective treatment systems for on-site implementation. Treatment systems based on sorption mechanisms are flexible, easy to operate and generate less sludge and several low-cost sorbents generated by forestry activities have advantageous physico-chemical characteristics. The current paper presents the preliminary results from a pilot treatment system consisting of an equalization tank, settling/sedimentation and two sorption reactors in parallel using Pinus sylvestris sawdust as sorbent implemented as part of an integrated water management plan in a wood-floor industry. The simple to operate and cost-effective pilot treatment system performs satisfactorily during an initial period of operation. The study shows an average 39% - 54% reduction of TPH;17% - 38% reduction of oil;2% - 15% of reduction of COD and;11% - 74% reduction of most toxic metals but for Co, Ni and Zn in the system B. Based on these results, Pinus sylvestris sawdust is a potential low-cost and abundant material to be considered for industrial wastewater treatment plants.
