观赏植物与驯化污泥联合修复垃圾渗滤液污染土壤

垃圾填埋场渗滤液污染土壤具有重金属-有机物复合污染的特性。研究了观赏植物广东万年青、白掌、孔雀竹芋和经垃圾渗滤液驯化的污泥对该污染土壤的修复效果,结果表明：采用单一植物修复时,广东万年青较白掌和孔雀竹芋对土壤污染物具有更强耐性,能在污染土壤中生长良好,对重金属Cd和Pb的富集能力也更强;驯化污泥能明显提高污染土壤中有机污染物的降解率,并使重金属Cd和Pb稳定态比例分别提高了34.7%和36.6%,降低了重金属的生物有效性。当采用广东万年青和驯化污泥联合修复时,污泥能促进植物的生长,且当污泥添加量为480 mg·kg-1时,联合修复对土壤中Cd、Pb及有机污染物的去除率分别较不加污泥的对照提高了51.7%、25.5%和40.2%。     

田湾核电站外围辐射环境监测工作的质量保证

总结了田湾核电站外围辐射环境监测中的质量保证实施情况，包括：人员培训和考核，仪器设备溯源，样品采集、运输、贮存及生物样品前处理的质控，样品分析和现场监测的质控，数据的记录处理和管理要求等，最后提出几点建议。     

Exploiting plant metabolism for the phytoremediation of persistent herbicides

Weed control by herbicides has helped us to create the green revolution and to provide food for at least the majority of human beings living today. However, some herbicides remain in the environment and pose an ecological problem. The present review describes the properties and fate of four representative herbicides known to be presistent in ecosystems. Metabolic networks are depicted and it is concluded that removal of these compounds by the ecologically friendly technique of phytoremediation is possible. The largest problem is seen in the uptake of the compounds into suitable plants and the time needed for such an approach.     

混合酶强化剩余污泥微生物燃料电池性能

为了提高剩余污泥为燃料的微生物燃料电池(SMFC)产电性能以及污泥减量化效果,在不同的温度(40、45和50℃)研究单室无膜微生物燃料电池中酶对SMFC产电特性的强化效果.加入单一酶(蛋白酶或α-淀粉酶)的结果表明,随着温度的上升,SMFC功率密度均上升,但40℃时强化效果最明显,与加入失活酶的对照组相比分别增加198％和130％.在40℃下,混合酶比(蛋白酶浓度:淀粉酶浓度)为2∶3时,SMFC最大功率密度为776 mW/m2.随着混合酶中淀粉酶的比例提高,SMFC库伦效率逐渐增加,当混合酶比为4∶1时,CE(库伦效率)可达18.3％,同时TCOD、TSS和VSS去除率分别为70.3％、66.7％和80.4％.因此,温度相对较低时,外加酶强化效果更明显;与单种酶相比,混合酶对SMFC产电性能和污泥减量化的强化效果更显著.     

Growth of Plants on TBT-contaminated Harbour Sludge and Effect on TBT Removal (10 pp)

Background Worldwide, large amounts of sediments have to be dredged annually from waterways and harbours. These sediments are sometimes polluted with a variety of toxic compounds. In some countries, including Belgium, the load with the biocide tributyltin (TBT) from ship coatings prohibits the dumping of harbour sludge into the sea. Land-based dumping is a commonly used alternative. Objective This research investigated the feasibility to use land-deposited harbour sludge for plant production. In a field trial, the growth of 38 more or less salt-tolerant plant species on low and high TBT-contaminated sediments was studied. The elimination of TBT from sludge with and without vegetation was compared. The uptake of TBT and its degradation products di- and monobutyltin (DBT and MBT) into harvest products under field conditions was determined. - Experimental Set-up. Sediments dredged in May 2003 from the brackish waters of the port of Antwerp were analysed in the laboratory for soil texture, pH, electroconductivity, sodium, magnesium, potassium, calcium, ammonium, nitrate, total nitrogen, chloride, sulphur and the organotins TBT, DBT and MBT. The sediments were lagooned for one year to dewater, desalinate and improve their structure. Salt-tolerant domestic and wild plants were selected and sown in May 2004. In August 2004, plants were harvested and the produced biomass was determined. Samples were taken from vegetated and non-vegetated top and bottom sediments and from plants growing above soil and analysed for TBT, DBT and MBT. Results The fresh sediments showed a good supply with nutrients and a neutral pH, but were rather saline (EC 14 mS cm-1 of the saturated paste extract). The salinity decreased to 3.7 mS cm-1 during lagoonation. The high and the low contaminated sediment had initially 43 and 1.6 mg TBT kg-1 dry weight, respectively. Besides TBT, several other contaminants were present in the sediments at critical levels. The biomass production of the plant species from the field trial ranged from 0.2 to 13 tons dry mass per hectare. Plants performing excellently were barley, sorghum, rape seed, a clover/grass mix and reed. If at all, a positive influence of TBT on plant growth was seen. TBT was degraded significantly faster (>40%) below barley. The uptake of TBT, DBT and MBT into stem and leaves of reed, grass and clover was very low, but measurable and not related to concentrations in soil. No uptake of TBT or its metabolites into corn of barley was found. Discussion This study confirmed former results: the toxicity of TBT to higher plants is low, and even high levels in soils would not be a hindrance for crop production. The removal of TBT seemed to be increased by both lagooning and plant growth, although the target values for sea dumping in use in certain European countries were not reached. A plausible explanation for the faster degradation of TBT under vegetation is that oxygen is a limiting factor, and plants dewater the soil, thus aerating it. The uptake of the organotins TBT, DBT and MBT into harvest products is probably due to attached soil particles. Conclusions To summarize, barley was the optimal species: it grew very well despite the salinity of the dredged sediments, it had a significantly positive effect on TBT removal; it showed no measurable uptake of TBT or the other butyltins into the harvested product; and it is a cash crop well established in European agriculture. Outlook The amounts of dredged sediments are high, and good soils are becoming increasingly rare. The feasibility of using dredged sediments for non-food production, such as energy crops, should be investigated by a critical risk assessment.     

钢渣掺量对泡沫混凝土砌块性能的影响

泡沫混凝土是一种环保、节能的保温隔热材料,以其优良的保温性能,受到越来越多研究者的关注。对钢渣的特性进行了分析测试,对钢渣不同掺量对泡沫混凝土砌块特性的影响进行了研究,结果表明,采用添加5％～35％钢渣所制备的钢渣泡沫混凝土砌块,其密度等级为JC／T1062—2007中的B10级,掺人5％、15％钢渣的泡沫混凝土抗压强度达到A3．5等级,掺人25％、35％钢渣的泡沫混凝土抗压强度达到A2．5等级。随着钢渣掺量的增大,抗压强度、抗折强度降低,吸水率增大。在同一钢渣掺量的情况下,泡沫混凝土砌块的抗压强度变化率增加显著,而且随着钢渣的加入量升高而增大。钢渣的加入有利于提高泡沫混凝土砌块的后期抗压强度。     

宁波市城市污水处理厂污泥处置方案探讨

随着城市污水处理率提高导致的污水污泥产量的增长趋势也使得污水污泥的处理问题更为突出。在总结国内外城市污泥处置技术发展趋势的基础上,结合宁波市的实际情况,根据无害化、减量化和资源化的原则,提出城市污泥近远期处置方案,并对处置方案作出可行性分析。     

预处理垃圾焚烧飞灰作为碱胶凝材料混合材的研究

试验分析了垃圾焚烧飞灰的主要化学成分及矿物组成,探讨了预处理垃圾焚烧飞灰作为碱胶凝材料混合材的可能性.研究表明,垃圾焚烧飞灰主要由黏土类矿物组成,飞灰直接作为混合材参与水化过程会产生明显膨胀现象,加入30%(质量分数)飞灰制成的矿渣/飞灰试块在成型1 d脱膜时膨胀率达到15.7%,标准养护28 d后无侧压抗压强度只有12.4 MPa.对飞灰进行热活化预处理,900℃条件下活化效果最佳,同样的飞灰掺量下,试块在标准养护28 d后无侧压抗压强度达到46.0 MPa,膨胀现象消失,且碱胶凝材料中重金属稳定性良好.     

Impact of Bioaugmentation with a Consortium of Bacteria on the Remediation of Wastewater-Containing Hydrocarbons (5 pp)

Goals, Scope and Background It has been observed that hydrocarbon treated wastewaters still contain high COD and a number of intermediates. This suggests that the required catabolic gene pool for further degradation might be absent in the system or, that its titer value is not significant enough. By providing the desired catabolic potential, the overall efficiency of the treatment system can be improved. This study aims to demonstrate this concept by bioaugmentation of a lab-scale reactor treating refinery wastewater with a consortium having the capacity to complement the alkB genotype to the available microbial population. Methods Two reactors were set up using activated biomass collected from a refinery treatment plant and operated at a continuous mode for a period of 8 weeks. The feed to both reactors was kept constant. Crude oil was spiked regularly. One reactor was bioaugmented with a consortium previously described for crude oil spill remediation. The efficiency of the bioaugmented reactor was demonstrated by reduced COD. The changes in the microbial population over a period of time were analyzed by RAPD. Catabolic activity of the biomass in both reactors was monitored by PCR. The presence of the catabolic loci was confirmed by Southern Hybridization. Results and Discussion 52.2% removal of COD was observed in the bioaugmented reactor while only 15.1% reduction of COD was observed in the reactor without bioaugmentation. The change in microbial population can be seen from the 4th week, which also corresponds to improved catabolic activity. The presence of the bedA locus was seen in all samples, which indicates the presence of aromatic degraders, but the appearance of the alkB locus, from the 6th week onwards, which was observed only in the samples from the bioaugmented reactor. The results suggest that the gene pool of the bioaugmented reactor has catabolic loci that can degrade accumulated intermediates, thus improving the efficiency of the system. Conclusions In this study, improvement of efficiency of bioremediation was demonstrated by addition of catabolic loci that are responsible for degradation. Bioaugmentation was carried out in biomass that was collected from an ETP (effluent treatment plant) treating hydrocarbon containing wastewater to study the strategies for improvement of the treatment system. Biostimulation, only marginally improved the efficiency, when compared to bioaugmentation. The improved efficiency was demonstrated by COD removal. The presence of the alkB locus suggests the importance of a catabolic gene pool that acts on accumulated intermediates. It is well documented that straight chain aliphatics and intermediates of aromatic compounds after ring cleavage, accumulate in refinery wastewater systems, thereby hindering further degradation of the wastewater. Supplementation of a catabolic gene pool that treats the lower pathway compounds and alkanes will improve the overall efficiency. In this study, results suggest that the alkB locus can also be used to monitor the degradative mode of the activated biomass. Recommendations and Perspective . Pollution from petroleum and petroleum products around the globe are known to have grave consequences on the environment. Bioremediation, using activated sludge, is one option for the treatment of such wastes. Effluent treatment plants are usually unable to completely degrade the wastewater being treated in the biological unit (the aerator chambers). The efficiency of degradation can be improved by biostimulation and bioaugmentation. This study demonstrates the improved efficiency of a treatment system for wastewater containing hydrocarbons by bioaugmentation of a consortium that supports degradation. Further experiments on a pilot scale are recommended to assess the use of bioaugmentation on a large scale. The use of molecular tools, like DNA probes for alkB, to monitor the system also needs to be explored.     

Heavy metals in untreated/treated urban effluent and sludge from a biological wastewater treatment plant

Background, Aim and Scope

The presence of heavy metals in wastewater is one of the main causes of water and soil pollution. The aim of the present study was to investigate the removal of Cd, Cu, Pb, Hg, Mn, Cr and Zn in urban effluent by a biological wastewater treatment, as well as to quantify the levels of As, Be, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sn, Tl, V and Zn in dewatering sludge from the Biological Wastewater Treatment Plant to Ribeirão Preto (RP-BWTP), Brazil.

Materials and Methods

Concentrations of Cd, Cr, Cu, Mn and Pb in wastewater and those of Ni in sludge were determined by atomic absorption spectrophotometry with graphite furnace atomization. Mercury concentrations in wastewater were measured by hydride generation atomic spectrophotometry, and Zn levels were determined by atomic absorption spectrophotometry using acetylene flame. In sludge, the levels of As, Be, Cd, Cr, Cu, Fe, Hg, Mn, Pb, Sn, Tl, V and Zn were determined by inductively coupled plasma-mass spectrometry.

Results

The percentages of removal efficiency (RE) were the following: Hg 61.5%, Cd 60.0%, Zn 44.9%, Cu 44.2%, PB 39.7%, Cr 16,5% and Mn 10.4%. In turn, the mean concentrations (mg/kg) of metals in dewatering sludge followed this increasing order: Tl (<0.03), Hg (0.31), Be (0.43), As (1.14), Cd (1.34), V (59.2), Pb (132.1), Sn (166.1), Cr (195.0), Mn (208.1), Ni (239.4), Cu (391.7), Zn (864.4) and Fe (20537).

Discussion

The relationship between metal levels in untreated wastewater, as well as the removal efficiency are in agreement with previous data from various investigators, It is important to note that metal removal efficiency is not only affected by metal ion species and concentration, but also by other conditions such as operating parameters, physical, chemical, and biological factors.

Conclusions

Metal values recorded for treated wastewater and sludge were within the maximum permitted levels established by the Environmental Sanitation Company (CETESB), São Paulo, Brazil.

Recommendations

There is an urgent need for the authorities who are responsible for legislation on sludge uses in agriculture of establishing safety levels for As, Be, Hg, Sn, Tl and V.

Perspectives

According to the current metal levels, RP-BWTP sludge might be used for agriculture purposes. However, for an environmentally safe use of sewage sludge, further studies including systematic monitoring are recommended. Annual metal concentrations and predicted variations of those elements in the sludge should be monitored.