Life cycle assessment of disposal of residues from municipal solid waste incineration: recycling of bottom ash in road construction or landfilling in Denmark evaluated in the ROAD-RES model

Two disposal methods for MSWI bottom ash were assessed in a new life cycle assessment (LCA) model for road construction and disposal of residues. The two scenarios evaluated in the model were: (i) landfilling of bottom ash in a coastal landfill in Denmark and (ii) recycling of bottom ash as subbase layer in an asphalted secondary road. The LCA included resource and energy consumption, and emissions associated with upgrading of bottom ash, transport, landfilling processes, incorporation of bottom ash in road, substitution of natural gravel as road construction material and leaching of heavy metals and salts from bottom ash in road as well as in landfill. Environmental impacts associated with emissions to air, fresh surface water, marine surface water, groundwater and soil were aggregated into 12 environmental impact categories: Global Warming, Photochemical Ozone Formation, Nutrient Enrichment, Acidification, Stratospheric Ozone Depletion, Human Toxicity via air/water/soil, Ecotoxicity in water/soil, and a new impact category, Stored Ecotoxicity to water/soil that accounts for the presence of heavy metals and very persistent organic compounds that in the long-term might leach. Leaching of heavy metals and salts from bottom ash was estimated from a series of laboratory leaching tests. For both scenarios, Ecotoxicity(water) was, when evaluated for the first 100 yr, the most important among the twelve impact categories involved in the assessment. Human Toxicity(soil) was also important, especially for the Road scenario. When the long-term leaching of heavy metals from bottom ash was evaluated, based on the total content of heavy metals in bottom ash, all impact categories became negligible compared to the potential Stored Ecotoxicity, which was two orders of magnitudes greater than Ecotoxicity(water). Copper was the constituent that gave the strongest contributions to the ecotoxicities. The most important resources consumed were clay as liner in landfill and the groundwater resource which was potentially spoiled due to leaching of salts from bottom ash in road. The difference in environmental impacts between landfilling and utilization of bottom ash in road was marginal when these alternatives were assessed in a life cycle perspective.     

Temporal variations of airborne particles concentration in the Brussels environment

We report and analyze data on the PM10 fraction of airborne particles measured at five recording stations in the Brussels region from October 2002 till September 2003. These stations are representative of the various activity sectors of the Brussels urban area. The objective was the determination of the origin of the PM10 particles (particles up to 10 μm) that are recorded in that region in order to follow the EU directives concerning tolerance level of airborne particles concentration. In order to evaluate the impacts of local and external factors that inject solid particles in the atmosphere of Brussels we compared concentration data from working and not working (holidays) periods. Moreover, we also compared concentrations from periods of agricultural activity and rest in the Brabant provinces surrounding the Brussels region for various crop types. The results lead to the conclusion that the impact or urban traffic is rather limited while that of the agricultural activities is important. Moreover, there appears a clear-cut distinction between different types of crops.     

Deterioration of water quality of Surma river

Surma River is polluted day by day by human activities, poor structured sewerage and drainage system, discharging industrial and household wastes. The charas (natural channels) are responsible for surface runoff conveyance from its urban catchments to the receiving Surma River. Water samples have been collected from a part of Surma River along different points and analyzed for various water quality parameters during dry and monsoon periods. Effects of industrial wastes, municipal sewage, and agricultural runoff on river water quality have been investigated. The study was conducted within the Chattak to Sunamganj portion of Surma River, which is significant due to the presence of two major industries – a paper mill and a cement factory. The other significant feature is the conveyors that travel from India to Chattak. The river was found to be highly turbid in the monsoon season. But BOD and fecal coliform concentration was found higher in the dry season. The water was found slightly acidic. The mean values of parameters were Conductivity 84–805 μs; DO: dry-5.52 mg/l, monsoon-5.72 mg/l; BOD: dry-1mg/l, monsoon-0.878 mg/l; Total Solid: dry-149.4 mg/l, monsoon-145.7 mg/l. In this study, an effort has been taken to investigate the status of concentration of phosphate (PO⁻⁴) and ammonia–nitrogen (NH₄–N) at four entrance points of Malnichara to the city, Guali chara, Gaviar khal and Bolramer khal. Data has been collected from March–April and September–October of 2004. Concentrations have been measured using UV Spectrophotometer. Although the phosphate concentration has been found within the limit set by DOE for fishing, irrigation and recreational purposes, however ammonia–nitrogen has been found to exceed the limit.     

Epiphytic lichens as biomonitors of atmospheric pollution in Slovenian forests

Two country-wide surveys using epiphytic lichens as biomonitors of atmospheric pollution carried out during 2000 and 2001 in Slovenia were compared with surveys in 1991 and 1992. In the first survey, epiphytic lichen cover was studied in more than 500 plots of the 4 x 4 km national grid carried out within the framework of forest decline inventories. In the second survey, the epiphytic lichen Hypogymnia physodes (L.) Nyl., was collected on a 16 x 16 km bioindication grid and analysed for S, N, As, Br, Ce, Cd, Cr, K, La, Mo, Rb, Sb, Th, U and Zn contents. Only 'forested area' sampling points were included in the present study. Lichen cover was low, with about 70% of plots with less than 10% foliose lichen cover. No relationship was found between Hypogymnia trace element, N and S concentrations and foliose epiphytic lichen cover.     

Recycled vertical flow constructed wetland (RVFCW)--a novel method of recycling greywater for irrigation in small communities and households

The use of greywater for irrigation is becoming increasingly common. However, raw greywater is often contaminated and can cause environmental harm and pose health risks. Nevertheless, it is often used without any significant pretreatment, a practice mistakenly considered safe. The aim of this study was to develop an economically sound, low-tech and easily maintainable treatment system that would allow safe and sustainable use of greywater for landscape irrigation in small communities and households. The system is based on a combination of vertical flow constructed wetland with water recycling and trickling filter, and is termed recycled vertical flow constructed wetland (RVFCW). The RVFCW's properties, removal efficiency, hydraulic parameters and feasibility were studied, as well as the environmental effects of the treated greywater, as reflected by soil and plant parameters over time. The RVFCW was efficient at removing virtually all of the suspended solids and biological oxygen demand, and about 80% of the chemical oxygen demand after 8h. Fecal coliforms dropped by three to four orders of magnitude from their initial concentration after 8h, but this was not always enough to meet current regulations for unlimited irrigation. The treated greywater had no significant negative impact on plants or soil during the study period. The feasibility analysis indicated a return over investment after approximately three years. We concluded that the RVFCW is a sustainable and promising treatment system for greywater use that can be run and maintained by unskilled operators.     

碱性催化剂对农业废物液化产生生物油和气体的影响

采用热化学处理法对农业废物玉米秸秆和苹果渣进行处理,3种碱性物质Na2CO3、K2CO3和KOH作为催化剂,都能不同程度提高液化生物油收率、减少固体残渣收率.但碱性催化剂会降低气体收率,因而不适合作为以获得气体产物为目的的生物质气化试验的催化剂.就增加液化生物油收率方面而言,Na2CO3的催化效果最好,KOH催化效果次之,K2CO3的催化效果最差.     

Development of a Test System for Assessing the Toxicity of Multicomponent Wastes Stored in the Natural Environment

A biological test system is proposed for assessing the toxicity of multicomponent wastes stored in the natural environment, with sewage sludge being used as an example. The principles of creating a test system and ranking the samples of multicomponent masses with respect to environmental hazard are discussed.     

Distribution of nitrogen and phosphorus and estimation of nutrient fluxes in the water and sediments of Liangzi Lake,China

Environmental Science and Pollution Research - Water samples and sediments from Liangzi Lake were taken and used to study the vertical distribution characteristics of nitrogen (N) and phosphorus...