A comparative study of microvillar enzyme activities in the prenatal diagnosis of cystic fibrosis

The potential of four enzyme-based analytical systems has been compared in the secondtrimester prenatal diagnosis of cystic fibrosis (CF). Direct activity measurements were made of γ-glutamyltranspeptidase (GGTP), aminopeptidase M (APM) and the intestinal isoenzyme of alkaline phosphatase (ALP). In the fourth system the proportions of total ALP inhibited by phenylalanine and homoarginine, respectively, were assessed. Each system was applied to amniotic fluid samples from 94 pregnancies with al in 4 risk of CF, divided into retrospective (36) and prospective (58) series. No system gave an absolute separation of affected from unaffected cases. Measurement of APM and intestinal ALP (phenylalanine-inhibitable ALP) gave a better detection rate for CF (35 of 41 cases, 85 per cent) than did measurement of GGTP (63 per cent) or assessment of ALP proportions (76 per cent). APM had a lower false positive rate (4 per cent) than intestinal ALP (8 per cent). For both the latter systems the detection rate of CF rose to 96 per cent (25 of 26), if gestations less than 17 weeks were excluded.     

化学生物絮凝工艺水质修复试验研究

介绍了污水化学生物絮凝处理工艺用于上海合流污水试验的典型工况 ,分析了此工艺和化学絮凝工艺在水质修复方面的差别 ,讨论了加药点对处理效果的影响。试验表明化学生物絮凝处理工艺优于化学絮凝工艺。     

空气氧化法处理碱渣的应用研究

采用低压空气氧化法使废碱液中的S^2-,SR-转变为S2O3^2-,RSSR，该过程能否成功操作取决于温度，压力和空气与水的接触，尤其是空气与水的传质速度将会较大的影响硫化物的氧化去除速率和空气中氧气的利用率。     

固定化聚铝的制备及在纸品加工废水处理中的应用

经水解尿素均匀沉淀 灼烧 ,在素瓷表面制备可能有共价结合的铝胶膜 ;铝胶薄膜载体与经复分解反应制得的氯化铝悬浊液共熟化 ,在其表面生成聚铝 ,经烧结进一步固化而制得固定化聚铝絮凝剂。经三级固定化絮凝剂床处理 ,纸品加工废水的COD、BOD、悬浮物、硫化物、色度等指标可分别降低 93 %、77%、97%、94%、80 %。     

Transformation and migration of phosphorus in excess sludge reduction pretreatment by alkaline ferrate oxidation combined with anaerobic digestion

Recently,more and more attention has been paid to the strong oxidation ability of newly prepared potassium ferrate(NAPF) in sludge reduction process,but less attention has been paid to the change of phosphorus in this process.The feasibility of phosphorus migration and transformation during excess sludge reduction pretre atment using NAPF pre-oxidation combined with anaerobic digestion was investigated.After 70 mg/g suspended solids NAPF pretreatment and 16 days anaerobic digestion,the solid-phase volatile suspended solids decreased by 44.2%,and much organic matter had been released into the liquid-phase and then degraded during digestion by indigenous microorganisms.As the sludge pre-oxidation process was performed,solid-phase organic phosphorus and chemically combined phosphorus also released into the liquid-phase as PO_4~(3-),peaking at 100 mg/L.During anaerobic digestion,the Fe~(3+)in the liquid-phase was gradually reduced to Fe~(2+),and then formed Fe~(2+)-PO_4~(3-) compound crystals and re-migrated to the solid-phase.The concentration of PO_4~(3-) decreased to 17.08± 1.1 mg/L in the liquid-phase after anaerobic digestion.Finally,the phosphorus in the Fe~(2+)-PO_4~(3-) compound accounts for 80% of the total phosphorus in the solid-phase.A large number of vivianite crystals in sludge were observed.Therefore,this technology not only effectively reduces sludge,but also increases the proportion of PO_4~(3-)in the sludge in the form of Vivianite.     

H2O2联合PAC对剩余污泥减量化的研究

为提高污水处理厂剩余污泥减量化效果,采用H 2O 2联合PAC技术强化调质与脱水效果,分析了H 2 O 2投加量、反应时间、PAC投加量、初始pH等因素对污泥破解及脱水性能的影响。结果表明:单独投加H 2 O 2,在H 2 O 2体积投加百分比为0.5%、反应时间为10 min的条件下可取得良好的溶胞效果,SCOD溶出率提高了近3倍;H 2 O 2联合PAC有利于污泥脱水性能的改善且不受初始pH(4.5~7)的影响,对于含水率为80%的污泥,调质、真空抽滤后的含水率可下降15%;在H 2 O 2的投加体积比为0.5%、反应时间为10 min、PAC投加量为绝干泥质量百分比2%~7%的条件下,污泥含水率随PAC投加量的增大而降低。     

Heavy metals and arsenic fixation into freshwater organic matter under Gammarus pulex L. influence

Organic sediments are a main sink for metal pollutants in aquatic systems. However, factors that make sediments a sink of metals and metalloids are still not clear. Consequently, we investigate the role of invertebrate shredders (Gammarus pulex L.) on quality of metal and arsenic fixation into organic partitions of sediment in the course of litter decay with laboratory microcosm experiments. During the decomposition of leaf litter, G. pulex significantly facilitated the development of small particles of organic matter. The capacity of metal fixation was significantly higher in smaller particles than leaf litter and litter residuals. Thus, G. pulex enhanced metal fixation into the organic partition of sediments by virtue of increasing the amount smaller particles in the aquatic system. Furthermore, invertebrates have a significant effect on formation of dissolved organic matter and remobilization of cobalt, molybdenum and cesium, but no significant effect on remobilization of all other measured elements.     

Growth and alkaline phosphatase activity of Chattonella marina and Heterosigma akashiwo in response to phosphorus limitation

The growth and alkaline phosphatase activity(APA) of two raphidophyceae species Chattonella marina and Heterosigma akashiwo were investigated in response to P-limitation and subsequent addition of dissolved inorganic phosphorus(DIP, Na H2PO4) and two dissolved organic phosphorus(DOP) compounds: guanosine 5-monophosphate(GMP) and triethyl phosphate(TEP). APA levels increased greatly after P-starvation as the decrease of the cellular phosphorus quotes(Qp). C. marina responded to P-limitation quickly and strongly, with 10-fold increase in APA within 24 hr after P-starvation. The larger difference between maximal and minimal QP values in C. marina indicated its high capacity in P storage. APA of H. akashiwo was maximally enlarged about 2.5 times at 48 hr of P-starvation. After the addition of nutrients, cell numbers of C. marina increased in all treatments including the P-free culture, demonstrating the higher endurance of C. marina to P-limitation. However, those of H. akashiwo increased only in DIP and GMP cultures. APA increased only after the addition of the monophosphate ester GMP. The results suggest that quick responses of C. marina to P-limitation, high capacity in P storage as well as endurance for P-depletion provide this species an ecological advantage in phytoplankton community competition under DIP-limited conditions.     

硫酸铁与聚合氯化铝处理城市景观水的比较实验研究

针对城市景观水的水质状况加剧恶化,本文对比在不同情况下用氯化铁及聚合氯化铝处理景观水,探讨了投加量、搅拌速度、搅拌时间、静沉时间以及pH对景观水有机物和浊度去除率的影响.结果表明:当水样pH值在6～8之间时,投加4～6mL混凝剂后,当先中速搅拌(120 r/min)2 min,最后慢速搅拌(60 r/min)搅拌10 min.此后静沉35 min,此时CODcr去除率及浊度去除率都可达到最佳情况;其中pH为8时,硫酸铁对CODcr去除率可达82％,浊度去除率率为92％;当PH为7时PAC对城市景观水CODcr的去除可达84％,浊度去除率率为96％.聚合氯化铝的处理效果优于硫酸铁,故而得出处理城市景观水时更适合选用聚合氯化铝.     

The fate of nitrogen in a moderately alkaline and calcareous soil amended with biosolids and urea

The determination of nitrogen (N) based loading rates for land application of biosolids is challenging and site specific. Over loading may contribute to environmental, agricultural, or human health problems. The objective of this study was to monitor N mineralization and losses in a moderately alkaline and calcareous desert soil amended with either anaerobically digested (AN) or lime-stabilized (LS) biosolids, and irrigated with and without urea enriched water. For Experiment 1, N inputs, leaching and residuals in soil were evaluated in an open soil column system. For Experiment 2, ammonia (NH₃) emissions were evaluated in a closed soil column system. In Experiment 1, AN and LS biosolids increased soil ON (organic N) by three and two fold, respectively. Respective net N mineralization of ON from biosolids alone was 90% and 62% without urea, and 71% and 77%, respectively with added urea. Nitrogen leaching losses and residuals in amended soil did not account for all N inputs into the soil/biosolids system. In Experiment 2, NH₃ emissions were not significantly different among treated soils with or without added urea, except LS amended soil receiving urea. Ammonia losses did not account for unaccounted N in Experiment 1. We concluded that deep placement and rapid mineralization of AN biosolids promoted anaerobic soil conditions and denitrification, in addition to the high denitrification potential of desert soil. LS biosolids showed greater potential than AN biosolids for safe and beneficial land application to desert soils regardless of biosolids placement and the inclusion of N rich irrigation water.