The Microbial Associations Developing on Experimental Trickling Filters Irrigated with Domestic Sewage

S ummary . The bacterial flora of the film which developed on experimental trickling filters irrigated with domestic sewage was dominated by Acinetobacter and yellow-pigmented Gram negative rod-shaped organisms and it was deduced that purification in certain aerobic waste treatment processes may depend upon an association of these 2 organisms. Further evaluation of the operational procedures likely to have a selective influence on the microbial association which becomes dominant was made in studies using synthetic sewage.     

The Bacteriology of Trickling Filters

Summary: The nature of the bacterial flora of trickling filters has been investigated. It consisted primarily of Gram-negative, rod shaped bacteria closely related to the flora of fresh water. These bacteria were able to grow on nutrient agar at 22° and belonged mainly to the genera Achromobacter, Alcaligenes, Flavobacterium, Pseudomonas and Zoogloea . The results failed to confirm the importance previously attributed to coli-aerogenes organisms, aerobic sporeformers and filamentous bacteria. The influence of homogenization on these findings is discussed. Further evaluation of the ecological importance of the various groups of bacteria was carried out by metabolic studies using synthetic sewage.     

Isolation of Ether-Resistant Enteroviruses from Sewage: Methodology

Experiments were conducted to determine whether polio type 1 (Mahoney and coxsackie A8 viruses adsorb onto cotton fibers of sewer swabs. Negative results were obtained. It has been shown that viruses may exist in sewage as free virus particles or as bound (adsorbed) virus particles. The sewer-swab method of sampling is superior because it filters out the bound virus over several days; when collected, it represents a catch (grab) sample at that particular time which may or may not contain free virus. A simple method for the preparation of sewage inocula for virus isolations is described which samples the bound virus fraction. Only ether-resistant viruses can be isolated, and an ultracentrifuge is not required. By this method, an isolation rate between 60 and 80% of positive sewer swabs can be achieved. Corresponding figures of 84 and 96% were achieved by concentration of sewer-swab eluates with an ultracentrifuge. Quantitative studies showed that the virus concentration in raw sewage can be as high as one infectious particle per 0.5 ml.     

Concentration of Enteroviruses on Membrane Filters

Enteroviruses can be made to adsorb or to pass through membrane filters by manipulation of the suspending medium. Salts facilitate virus adsorption, but membrane-coating components (MCC) interfere. Because cells release MCC into the culture medium during viral growth, MCC must be removed before virus can be adsorbed to membranes. Adsorbed virus can be eluted with diluents containing MCC (cell extracts or serum) or agents that reduce surface tension (sodium lauryl sulfate). By membrane adsorption and elution, enteroviruses can be readily concentrated and quantitatively recovered from crude virus harvests.     

Removal of Styrene from Waste Gas Using a Biological Trickling Filter

Biodegradation of styrene in a biological trickling filter on lava stones was investigated, firstly, with the addition of silicon oil and, secondly, without the addition of silicon oil. After 400 days of trial runs the experimental results revealed that the biodegradation capacity of styrene in the trickling filter reached 537 g/m³ × h with a degradation yield of 96.8 % at an air inlet concentration of 1.06 g/m³ of styrene and a space velocity of 157 m/h in the presence of silicon oil. A removal of styrene up to 2.9 kg/m³ × h was obtained when the styrene input concentration in a constant inlet air flow of 0.78 m³/h was increased up to 6.6 g/m³. Interestingly, it was observed that after a period of 400 days, the seven dominant strains were completely different from those present in the inoculum. Surprisingly, this population was able to grow in an aqueous liquid phase without silicon oil on a styrene concentration of 45.5 g/L. In the biological trickling filter with lava stones but without silicon oil, the biodegradation capacity of styrene was 464 g/m³ × h with a removal yield of 98.3 % at an air inlet concentration of 1.03 g/m³ of styrene and a space velocity of 137 m/h. As in the presence of silicon oil, a removal of styrene of up to 2.375 kg/m³ × h was achieved when the air flow rate was kept constant and the styrene input concentration was increased. These experiments suggested that the biphasic medium could be very efficiently used for the selection of adapted strains for the removal of insoluble or poorly soluble organic compounds, rather than being used for long‐term degradation under industrial conditions.     

Evaluation of Filters for Removal of Bacteriophages from Air

Glass wool, nonabsorbent cotton, fiberglass filter medium, and a commercial absolute filter were tested for effectiveness in removing aerosolized bacterial viruses under low flow rate (1 ft(3)/min) and high flow rate (10 to 25 ft(3)/min) air-flow conditions. Special equipment was designed for measurement of filter efficiencies under the two air-flow conditions. Under low air-flow rate test conditions, glass wool was only 98.543 to 99.83% efficient, whereas cotton (five layers), fiberglass medium (three layers), and the commercial absolute filter were at least 99.900, 99.999, and 99.999 efficient, respectively. Glass wool and cotton were not used under higher air-flow conditions because they were difficult to assemble in leak-tight filters. The commercial absolute filter and fiberglass medium (three layers) were at least 99.990 and 99.999% efficient, respectively, under the higher air flow conditions. A stainless-steel filter of simple design and fitted with three layers of fiberglass medium was found to be greater than 99.999% efficient in removing high concentrations (20,000 to 70,000 plaque-forming units per cubic foot) of aerosolized bacteriophages from air moving at a low flow rate (1 ft(3)/min). Use of this filter on pressure-vacuum tanks in the fermentation industry is suggested. Several other uses of such a filter are proposed.     

Nitrogen and Phosphorus Removal from Combined Sewage Components by Microbial Activity

When primary domestic sewage sludge was combined with settled sewage or secondary-treatment plant effluent, synergism resulted. The activity (measured by oxygen uptake, and the removal of Kjeldahl nitrogen and orthophosphate from solution) which resulted from incubating sludge together with settled sewage exceeded the sum of the activities when these components were incubated separately. A similar synergistic effect occurred with sludge and effluent. The sewage sludges were deficient in readily available nitrogen, but no shortage of phosphorus was demonstrated. The addition of ammonium and orthophosphate salts to sludge, in concentrations equivalent to those found in settled sewage and effluent, stimulated sludge oxygen uptake at least 80% as much as settled sewage or effluent. It is suggested that the synergism reflects increased microbial activity resulting from widened carbon-nitrogen and carbon-phosphorus ratios achieved by combining sludge with nutrient-rich settled sewage or effluent.     

Prevalence of Nonpolio Enteroviruses in the Sewage of Guangzhou City,China, from 2009 to 2012

The human-pathogenic viruses in urban sewage have been extensively monitored to obtain information on circulating viruses in human communities. Enteroviruses (EVs) excreted by patients who present with diverse clinical syndromes can remain infectious in the environment for several weeks, and limited data on circulating environmental EVs are available. A 4-year (2009 to 2012) surveillance study was conducted to detect nonpolio enteroviruses (NPEVs) in the urban sewage of Guangzhou city, China. After the viruses in the sewage samples were concentrated and isolated, molecular identification was used to detect and type the NPEVs. During the 4-year study, 17 different NPEV serotypes were identified in the sewage of Guangzhou city. The most common serotypes were echovirus 11 (ECHO11), ECHO6, ECHO7, and ECHO12 and coxsackie group B viruses 5 (CVB5) and CVB3. The predominant serotypes were influenced by spatial and temporal factors and differed each year. CVB5 was commonly detected in 2009 and 2010 but was rarely isolated in 2011 and 2012. In contrast, CVB3 was not observed in 2009 and 2010 but was increasingly detected in 2011 and 2012. Our study provides an overview of the serotype distribution and circulation patterns of NPEVs in the sewage of Guangzhou, China. In the absence of a systematic EV disease surveillance system, the detection and characterization of sewage-borne NPEVs will help us better understand the changes in EV disease trends and the epidemic background of circulating EVs, which could help interpret the EV trends and warn of future outbreaks in this area.     

生物淋滤技术在去除污泥中重金属的应用

利用微生物方法去除污泥中重金属（生物淋滤法）具有成本低,去除效率高,脱毒后污泥脱水性能好等优点,近年来在国际上备受关注,生物淋滤法采用的主要细菌为氧化亚铁硫杆菌（Thiobacillus ferrooxidans)和氧化硫硫杆菌（Thiobacillus thiooxidans),在其作用下,污泥中以难溶性金属硫化物被氧化成金属硫酸盐而溶出,通过固液分离即可达到去除重金属的目的,污泥的生物淋滤效果受温度、O2和CO2浓度,起始pH、污泥种类与浓度、底物种类与浓度、抑制因子、Fe^3 浓度等的影响,较为详细地介绍了生物淋滤法的作用机理及高效去除污泥中重金属的操作程序,并对其在环境污染治理方面的应用前景作了分析。     

Removal of Nonferrous Heavy Metals from Industrial Sewage Using Biosorbents

Producers of the antibiotics neomycin and lincomycin were most potent in sorbing nonferrous metals; they removed 99% Zn and Cd and 95% Ni. The degree of metal sorption increased with an increase in solution pH and calcium content in the biomass. Dynamic studies of biosorbents prepared from a microbial biomass showed that neomycin industrial waste products are highly efficient in treating galvanic washing water. The total dynamic exchange capacities by nickel and cadmium were 6.85 and 7.16 mg/ml, respectively.     

Preservation of Enteroviruses by Freeze-Drying

A method was developed for freeze-dry stabilization of poliovirus type 3. An ultrafiltration procedure was used to remove salts from infected tissue culture fluid, and the virus was freeze-dried after suspension in an alkaline organic buffer. This method was further tested with other picornaviruses including poliovirus types 1 and 2, coxsackieviruses A9, A20, B2, and B5, echovirus 11, and the encephalomyocarditis virus. Freeze-dried preparations of the poliovirus could be shipped to distant laboratories at ambient temperature with excellent retention of infectivity. Data are presented showing effects of freeze-drying as well as results of exposure to temperatures to 37 C.     

Removal of Heavy Metals from Sewage Sludge Used as Soil Fertilizer

This work has examined sewage sludge of the following heavy metal concentrations (mg/kg): Cd-3.43; Co-5.25; Cu-131; Fe-51300; Mn-177; Ni-37.5; Pb-104; Zn-3300. Metals speciation by sequential extraction according to Tessier et al. (1979), and Rudd et al. (1988), and a procedure recommended by European Community Bureau of Reference (BCR) (Ure et al., 1993; Quevauiller et al., 1996; Davidson et al., 1999), as well as analysis of chemical forms of metals, have been carried out. It has been found that only Zn concentration is higher than the value permissible for agricultural sewage sludge application (2500 mg/kg). The results obtained by Tessier et al. (1979) Tessier, A., Campbell, P. C. and Bisson, M. 1979. Sequential extraction procedure for the speciation of particulate trace metals.. Anal. Chem., 51: 844–851. [Crossref], [Web of Science ®] [Google Scholar], and BCR procedures (Ure et al., 1993; Quevauiller et al., 1996; Davidson et al., 1999) appeared to be consistent. A comparison of the sequential analysis and the analysis of chemical forms of metals indicates that the sum of metal concentrations for the exchangeable, carbonate and bound to Fe/Mn oxyhydroxides forms (found by Tessier et al., 1979, and BCR analyses (Ure et al., 1993; Quevauiller et al., 1996; Davidson, et al., 1999)) corresponds to the sum of sulfate, oxide, metallic and siliceous forms. The concentrations of the forms bound to organic matter or sulfides correspond to the sulfide form while the residue corresponds to the ferrate form. Preparative extraction of metals from the sewage sludge using sodium salt of ethylenediaminetetraacetic acid (EDTA-Na), sodium pyrophosphate (V) and ammonia water has also been investigated. As far as the examined leaching agents are concerned, EDTA-Na appeared to be the best. Single leaching with this agent results in the following metal concentrations remaining in the sludge (mg/kg): Cd-1.1; Co-2.1; Cu-105; Fe-17700; Mn-28.3; Ni-12.8; Pb-44; Zn-1200. They meet the requirements of Polish regulations concerning the use of sewage sludge as a soil fertilizer.     

A Method for the Removal from Membrane Filters of Micro-Organisms Filtered from Water and Air

S ummary : The micro-organisms in tap water were quantitatively (99%) retained by Oxoid membrane filters. The trapped organisms were extracted from the membrane filter by a simple washing process using glass beads or a magnetic stirrer. For counts on air, the membrane filter was considerably more efficient than an ammonium alginate filter in trapping bacteria, but both techniques were equally satisfactory for moulds.     

Filtration Methods for Recovering Enteroviruses from Foods

A set of simple, rapid filtration methods has been developed for recovering enteroviruses from foods. The methods employ quite inexpensive equipment, and the resulting extract might be concentrated in any of several ways. Three model enteroviruses were apparently recovered with at least 80% efficiency when inoculated, at levels ranging from thousands to one plaque-forming unit per 20-g sample, into eleven foods representing six major food groups.     

The Removal of Salmonellas in Conventional Sewage Treatment Processes

The numbers of salmonellas in raw sewage entering a treatment plant varied hourly and diurnally; their peak concentration preceded the peak influent waste water flow into the plant by about 2 hours. Salmonellas were detected in all raw influent samples collected from 2 sewage works and the mean population level at the daily peak period was 3000 organisms/1. On average. 70–80% of the salmonellas were removed during primary sedimentation when upwards of 74–84% of solids were removed. Biological treatment and secondary sedimentation removed a further 70–100% of the pathogen. Compared with the activated sludge process the trickling filters were less efficient in removing salmonellas and they were adversely affected by increased loading following rainfall. Considering the whole treatment process, the Guildford works with its activated sludge treatment removed an average of 99–83% salmonellas while the Woking works with its trickling filter plant removed an average of 93–04% of the organisms. The large variance in the numbers of salmonellas in the final effluent from the trickling filters suggest that greater emphasis should be placed on the actual quality of the effluent rather than on percentage removal efficiencies.     

毛蚶中肠道病毒检测方法的建立

本文建立了检测毛蚶中肠道病毒的方法。病毒在pH4.5时吸附于毛蚶组织,离心后用pH9.5甘氨酸盐水将病毒从毛蚶组织中洗脱出来,并用0.0005mol/L三氯化铝代替Johnson法中的Cat—Floc,达到去除细胞毒性物质的目的。经过再一次离心,利用牛肉浸膏在pH3.5—4.0时凝聚并吸附病毒的特性使洗脱液中的病毒得到浓缩。离心后沉淀溶解于0.1mol/L磷酸氢二钠溶液。用本法提取毛蚶中脊髓灰质炎病毒,当病毒含量为每克组织3.5×10~5至35PFU时,平均回收率为71.2％。