A/O活性污泥系统与生物膜系统处理炼焦工业废水对比试验研究

考察了在相同的运行条件下,A/O活性污泥系统和生物膜系统对炼焦工业废水的处理效果。试验结果表明,生物膜系统的抗冲击负荷能力强,处理效果优于A/O活性污泥系统,达到相同污染物去除率,生物膜系统的总水力停留时间缩短了7.5h,而且运行管理简单。     

汞对河道底泥的污染与防治

本文以某金矿为例,通过对含汞废水跟踪监测,论述了汞对河道底泥的污染状况,同时提出了防治措施。     

Microbial quantification in activated sludge: the hits and misses

Since the implementation of the activated sludge process for treating wastewater, there has been a reliance on chemical and physical parameters to monitor the system. However, in biological nutrient removal (BNR) processes, the microorganisms responsible for some of the transformations should be used to monitor the processes with the overall goal to achieve better treatment performance. The development of in situ identification and rapid quantification techniques for key microorganisms involved in BNR are required to achieve this goal. This study explored the quantification of Nitrospira, a key organism in the oxidation of nitrite to nitrate in BNR. Two molecular genetic microbial quantification techniques were evaluated: real-time polymerase chain reaction (PCR) and fluorescence in situ hybridisation (FISH) followed by digital image analysis. A correlation between the Nitrospira quantitative data and the nitrate production rate, determined in batch tests, was attempted. The disadvantages and advantages of both methods will be discussed.     

Biodiversity of an Acinetobacter population isolated from activated sludge

A culturable microbial community from a sewage treatment plant collecting mainly surfactant-enriched wastes was selected on minimal medium containing two nonylphenol ethoxylates as sole carbon source. Biodiversity of the community was assessed on fifty randomly chosen isolates by a combination of molecular techniques. Isolates were first analysed by amplified 16S ribosomal DNA restriction analysis (ARDRA); most of them (75%) were assigned to the genus Acinetobacter on the basis of 16S ribosomal DNA sequencing. Random amplified polymorphic DNA (RAPD) fingerprinting and the analysis of plasmid content showed a high degree of genetic variability and suggested a marked horizontal gene transfer.     

Inhibition of anaerobic phosphate release by nitric oxide in activated sludge

Activated sludge not containing significant numbers of denitrifying, polyphosphate [poly(P)]-accumulating bacteria was grown in a fill-and-draw system and exposed to alternating anaerobic and aerobic periods. During the aerobic period, poly(P) accumulated up to 100 mg of P x g of (dry) weight. When portions of the sludge were incubated anaerobically in the presence of acetate, 80 to 90% of the intracellular poly(P) was degraded and released as orthophosphate. Degradation of poly(P) was mainly catalyzed by the concerted action of polyphosphate:AMP phosphotransferase and adenylate kinase, resulting in ATP formation. In the presence of 0.3 mM nitric oxide (NO) in the liquid-phase release of phosphate, uptake of acetate, formation of poly-beta-hydroxybutyrate, utilization of glycogen, and formation of ATP were severely inhibited or completely abolished. In cell extracts of the sludge, adenylate kinase activity was completely inhibited by 0.15 mM NO. The nature of this inhibition was probably noncompetitive, similar to that with hog adenylate kinase. Activated sludge polyphosphate glucokinase was also completely inhibited by 0.15 mM NO. It is concluded that the inhibitory effect of NO on acetate-mediated phosphate release by the sludge used in this study is due to the inhibition of adenylate kinase in the phosphate-releasing organisms. The inhibitory effect of nitrate and nitrite on phosphate release is probably due to their conversion to NO. The lack of any inhibitory effect of NO on adenylate kinase of the poly(P)-accumulating Acinetobacter johnsonii 210A suggests that this type of organism is not involved in the enhanced biological phosphate removal by the sludges used.     

Numerical taxonomy of Skermania piniformis and related isolates from activated sludge

This study compared 21 female adult psychiatric patients diagnosed with dissociative identity disorder (DID) with 21 female adult nondissociative psychiatric patients to determine whether DID patients exhibit a distinguishing set of clinical features, and perceptual, attentional, and cognitive processes. Participants were assessed with the Dissociative Disorders Interview Schedule to assess diagnostic status. Group scores on the Dissociative Experiences Scale, Tellegen Absorption Scale, Childhood Trauma Questionnaire, Brief Symptom Inventory, and the Rorschach test were compared. DID participants reported earlier and more severe childhood trauma, more dissociative symptoms, and a greater propensity for altered states of consciousness. The DID participants also exhibited increased projective and imaginative activity, a diminished ability to integrate mental contents, a complex and driven cognitive style, and a highly unconventional view of reality.     

Isolation and identification of bacteria from activated sludge purifying petroleum wastewaters

Several strains growing well in minimal media with 500 and 1000 mg/l of oil or phenol as a sole carbon source were isolated from activated sludge purifying petroleum waste waters and identified. Five of the best growing strains classified as Arthrobacter, Pseudomonas, Xanthomonas and Enterobacter were selected and their capacity to remove petroleum components and phenol (in the oil fraction of petrochemical waste waters) was studied. The enzymatic activity of the strains, including respiration intensity and dehydrogenase activity was also determined. All the examined strains were found to use oils as the sole source of carbon (percent age of the oils reduction during cultivation of the individual strains ranged from 58 to 78). Phenol was completely reduced by only one strain. The rest of the strain removed only from 7 to 24% of this compound. The activity of dehydrogenases and the respiration intensity in the presence of the studied substrates -- oil and phenol was low for all the examined strains.     

Selenite bioremediation potential of indigenous microorganisms from industrial activated sludge

Ten bacterial strains were isolated from the activated sludge waste treatment system (BIOX) at the Exxon refinery in Benicia, California. Half of these isolates could be grown in minimal medium. When tested for selenite detoxification capability, these five isolates (members of the genera Bacillus, Pseudomonas, Enterobacter and Aeromonas), were capable of detoxifying selenite with kinetics similar to those of a well characterized Bacillus subtilis strain (168 Trp+) studied previously. The selenite detoxification phenotype of the Exxon isolates was stable to repeated transfer on culture media which did not contain selenium. Microorganisms isolated from the Exxon BIOX reactor were capable of detoxifying selenite. Treatability studies using the whole BIOX microbial community were also carried out to evaluate substrates for their ability to support growth and selenite bioremediation. Under the appropriate conditions, indigenous microbial communities are capable of remediating selenite in situ.     

Investigation of methods for lessening drainage from sludge pits into underground and river waters via physicochemical activation of belite sludge

Possible routes of conversion of belite sludge into mineral paragenesis, which is stable under hypergene conditions, changes the physical structure of sludge, and reduces its filtrating properties, are investigated using thermodynamic modeling methods. It is found that the filtration drainage may be reduced by clinker minerals (carboaluminates and tobermorite) formed by using finely dispersed colmatant prepared from amorphous silicon dioxide. Finely dispersed powder from silicon production (cyclone collector of gas-cleaning systems) may be used as a raw material in colmatant production.     

Real-time control of aerobic/anoxic digestion for waste activated sludge

Experiments were conducted to study the performance characters of aerobic/anoxic(A/A)digestion of sludge at 30±1℃,while the sludge retention time(SRT)was kept 16 d.The variations of oxidation reduction potential(Eh)and pH were continuously monitored during the A/A digestion and the conversions of ammonium and nitrate were investigated.Important features on both Eh and pH profiles were identified to develop process control strategy.Since the feature point on Eh profile where d2 Eh/dt2=0 is very stable during anoxic cycle,it cart be used to determine the end of denitrification.The end of nitrification can be identified according to dpH/dt=0.A real-time control strategy of A/A digestion of sludge was developed and tested with pH and Eh as control parameters.It is shown that the performance of the real-time control strategy is better than that of a fixed-time control strategy.While the real-time controlled A/A digestion system call achieve a similar volatile suspended solids(VSS)destruction efficiency of 35.2% as a continuously aerated system,it improves the superuatant quality in a shorter aeration time(7.75 d for a 20 d period).     

Population dynamics of phenol-degrading bacteria in activated sludge determined by gyrB-targeted quantitative PCR

A method for quantifying bacterial populations introduced into an activated-sludge microbial community is described. The method involves extraction of DNA from activated sludge, appropriate dilution of the extracted DNA with DNA extracted from nonintroduced activated sludge, PCR amplification of a gyrB gene fragment from the introduced strain with a set of strain-specific primers, and quantification of the electrophoresed PCR product by densitometry. The adequacy of the method was examined by analyzing the population dynamics of two phenol-degrading bacteria, Pseudomonas putida BH and Comamonas sp. strain E6, that had been introduced into phenol-digesting activated sludge. The density of each of the two populations determined by the PCR method immediately after the introduction was consistent with the density estimated from a plate count of the inoculum. This quantitative PCR method revealed different population dynamics for the two strains in the activated sludge under different phenol-loading conditions. The behavior of both of these strains in the activated sludge reflected the growth kinetics of the strains determined in laboratory axenic cultures.     

Mass spectra of acetylenic fatty acid methyl esters and derivatives

A series of isomeric methyl octadecynoates was analyzed by mass spectrometry; each isomer gave a unique spectrum. The characteristic ions were those resulting from a McLafferty rearrangement of the allenic sites or of the already-rearranged allenic sites. The acetylenic esters were also subjected to oxymercuration whereupon a carbonyl group was formed at either of the original actylenic carbon atoms providing two oxostearates. Further reaction with NaBH4 formed hydroxy esters which, after silylation, gave diagnostic mass spectra indicative of the triple bond location. Applied to esters with both double and triple bonds, this procedure permitted differentiation between the two types of unsaturation. Methoxyl groups marked the original double bond locations and hydroxyls did so for triple bonds.     

Quantification of Gordona amarae strains in foaming activated sludge and anaerobic digester systems with oligonucleotide hybridization probes

Previous studies have shown the predominance of mycolic acid-containing filamentous actinomycetes (mycolata) in foam layers in activated sludge systems. Gordona (formerly Nocardia) amarae often is considered the major representative of this group in activated sludge foam. In this study, small-subunit rRNA genes of four G. amarae strains were sequenced, and the resulting sequences were compared to the sequence of G. amarae type strain SE-6. Comparative sequence analysis showed that the five strains used represent two lines of evolutionary descent; group 1 consists of strains NM23 and ASAC1, and group 2 contains strains SE-6, SE-102, and ASF3. The following three oligonucleotide probes were designed: a species-specific probe for G. amarae, a probe specific for group 1, and a probe targeting group 2. The probes were characterized by dissociation temperature and specificity studies, and the species-specific probe was evaluated for use in fluorescent in situ hybridizations. By using the group-specific probes, it was possible to place additional G. amarae isolates in their respective groups. The probes were used along with previously designed probes in membrane hybridizations to determine the abundance of G. amarae, group 1, group 2, bacterial, mycolata, and Gordona rRNAs in samples obtained from foaming activated sludge systems in California, Illinois, and Wisconsin. The target groups were present in significantly greater concentrations in activated sludge foam than in mixed liquor and persisted in anaerobic digesters. Hybridization results indicated that the presence of certain G. amarae strains may be regional or treatment plant specific and that previously uncharacterized G. amarae strains may be present in some systems.