CO2 mineral sequestration in oil-shale wastes from Estonian power production

In the Republic of Estonia, local low-grade carbonaceous fossil fuel--Estonian oil-shale--is used as a primary energy source. Combustion of oil-shale is characterized by a high specific carbon emission factor (CEF). In Estonia, the power sector is the largest CO(2) emitter and is also a source of huge amounts of waste ash. Oil-shale has been burned by pulverized firing (PF) since 1959 and in circulating fluidized-bed combustors (CFBCs) since 2004-2005. Depending on the combustion technology, the ash contains a total of up to 30% free Ca-Mg oxides. In consequence, some amount of emitted CO(2) is bound by alkaline transportation water and by the ash during hydraulic transportation and open-air deposition. The goal of this study was to investigate the possibility of improving the extent of CO(2) capture using additional chemical and technological means, in particular the treatment of aqueous ash suspensions with model flue gases containing 10-15% CO(2). The results indicated that both types of ash (PF and CFBC) could be used as sorbents for CO(2) mineral sequestration. The amount of CO(2) captured averaged 60-65% of the carbonaceous CO(2) and 10-11% of the total CO(2) emissions.     

活性污泥数学模型中溶解性惰性COD的测定

溶解性惰性COD(S1)是决定污水处理厂出水COD能否达标的关键指标.针对溶解性微生物产物对S1测定的影响,对S1的测定方法进行了修正.实际生活污水的测定试验表明,该方法具有很好的重现性和准确性.在长距离输送的合流制污水的实测过程中发现:晴天条件下,瞬时样的S1/COD和Si/SCOD(溶解性COD)变动较大,在24 h混合样中St/COD和S1/SCOD较为稳定,分别为(9.2±0.3)%和(27.3士2.1)%;暴雨天气下,S1/COD和S1/SCOD会明显增加.     

投加沸石粉活性污泥搅拌参数优化及其对离子交换速率的影响研究

在0.3 m×0.3 m×0.36 m方形搅拌槽中初步探讨了不同的搅拌器类型、安装高度以及曝气强度对投加了沸石粉的高浓度活性污泥悬浮状态的影响,并根据固液悬浮理论确定了最佳的搅拌参数.同时,进行了不同搅拌速率下沸石对污水中氨氮的离子交换动力学研究.结果表明在无曝气的情况下,选用三叶推进式搅拌器,搅拌器离底高度为1/3搅拌器直径时所需要的临界搅拌速率最低.曝气有助于反应池中污泥的悬浮,对于30 g/L的污泥,当曝气强度由10 m3/(m2·h)增大1倍时,临界搅拌速率降低了50%.搅拌速率为120 r/min时,沸石对污水中氨氮的离子交换速率受膜扩散过程控制,当其增大为180 r/min时,其控制步骤为粒内扩散,沸石粉活性污泥达到完全均匀悬浮的临界搅拌速率不足以满足传质的要求.需增大一定程度.     

The leaching of additive-derived flame retardants (FRs) from plastics in avian digestive fluids: The significant risk of highly lipophilic FRs

The exposure to plastic debris and associated pollutants for wildlife is of urgent concern,but little attention has been paid on the transfer of plastic additives from plastic debris to organisms. In the present study, the leaching of incorporated flame retardants(FRs),including polybrominated diphenyl ethers(PBDEs), alternative brominated FRs(AFRs), and phosphate flame retardants(PFRs), from different sizes of recycled acrylonitrile-butadienestyrene(ABS) polymer were investigated in avian digestive fluids. The impact of co-ingested sediment on the leaching of additive-derived FRs in digestive fluids was also explored. In the recycled ABS, BDE 209(715 μg/g) and 1, 2-bis(2,4,6-tribromophenoxy) ethane(BTBPE,1766 μg/g) had the highest concentrations among all target FRs. The leaching proportions of FRs were higher in finer sizes of ABS. The leaching proportions of FRs from recycled ABS increased with elevated logK OWof FRs. In the tests with coexisted ABS and sediment, hexato deca-BDEs, BTBPE, and decabromodiphenyl ethane(DBDPE) migrated from ABS to sediment, which resulted in the less bioaccessible fractions of these FRs in gut fluids. More lipophilic chemicals tended to be adsorbed by sediment from ABS. The results suggest the migration of additive-derived FRs from plastics to other indigestible materials in digestive fluids. The findings in this study provide insights into the transfer of additive-derived FRs from plastics to birds, and indicate the significant contribution of FR-incorporated plastics to bioaccumulation of highly lipophilic FRs.     

Electrochemical detoxification of four phosphorothioate obsolete pesticides stocks

The phosphorothioate pesticides are widely used for crop production and fruit tree treatment, but their disposal causes serious environmental problems. Four commercial phosphorothioate pesticides (Demeton-S-methyl, Metamidophos, Fenthion and Diazinon) were treated by an electrolysis system using Ti/Pt as anode and stainless steel 304 as cathode. A number of experiments were run in a laboratory scale pilot plant and the results are presented. For Fenthion the achieved reduction was over 60%, while for Demeton-S-methyl, Metamidophos and Diazinon was more than 50%. Diazinon had the lowest energy demand. The COD/BOD5 ratio was improved considerably after electrolysis for all four pesticides examined. As a conclusion, electrochemical oxidation could be used as a pretreatment method of the pesticides detoxification.     

山体绕流和尾流区气态污染物输送扩散规律的研究

采用瞬时烟线仪与迪沙(DISA)热线风速仪相结合的方法探测了山体的绕流区和尾流区结构。试验结果表明,山体的绕流和尾流对低架源排放的气态污染物扩散影响甚大,山体绕流可改变烟流的地面浓度分布.结果还表明,我们所用的探测流向的方法较为有效和准确.     

H2O2对载银TiO2光催化降解Aroclor1260的影响

光催化氧化法降解水中有机污染物是近来发展较为迅速的废水处理技术，以锐钛型载银TiO2为催化剂，在发射光谱波长为254nm，功率的15W紫外灯照射下，考察不同H2O2浓度对Aroclor1260的光催化降解的影响，结果表明：低浓度的H2O2对Aroclor1260的光催化降解有促进作用，而当H2O2的浓度高于30mol/l时，光催化降解受到抑制，而且这种影响对不同PCB单体化合物的效果基本一致。     

城市污水净化的环境效益与环境影响分析

对佛山城市污水净化系统的环境响应和效益预测原则，城市污水净系统正式运转将对佛山水道化纤厂至人民桥段及佛山涌水质有明显改善，其社会效益十分显著，但净化系统的建设交将带来以恶臭、卫生防疫和噪声等方面为主的不利环境影响。因此在城市环境建设中应尽量减少城市污水净化的负面影响，充分发挥其环境效应和社会效益，为城市环境综合整治创造良好的条件。