Ultra-violet absorption as a tracing technique for sewage dispersion and water masses in two red sea coastal lagoons in Jeddah

The u.v. absorbance is measured in water samples, collected on six successive cruises made within 1 year, from two Saudi sewage-affected fjord-like lagoons in Jeddah (Arbacen and Reayat Al-Shabab). The hydrochemical elements, salinity, phosphate and ammonia are also measured. The horizontal and vertical distribution pattern of u.v. absorbance and that for the other hydrochemical elements are found to coincide with each other to a great extent. The direction of the discharged wastewater spread at the surface can be easily identified. Three distinct water layers are observed. The surface layer is diluted by sewage effluent containing high values of u.v. absorbance, phosphate and ammonia. The intermediary layer has almost the same properties as the water outside the lagoon mouth at the same level where it is less diluted (i.e. less polluted). The third layer at the bottom (old water) where the water is dammed by the sills is more saline. It has exceptionally high values out of the four elements studied. This situation prevails almost throughout the year except during the intermittent flushing periods in winter and early spring, when the stratification is disturbed. The advantage of using u.v. absorbance measurement is that it can be read directly in the water samples without any chemical pre-treatment and so no special training is needed.     

The use of bromophenol blue as a tracer in sewage works

A reliable method for the quantitative assessment of water mixing in sewage works is presented. Using a rapid visible-spectroscopic technique to assay Bromophenol Blue, both laboratory and in situ adsorption/degradation studies are presented which confirm that this dye may be used quantitatively in tracer experiments.     

The use of an upflow fixed bed reactor for treatment of a primary settled domestic sewage

This study presents and demonstrates results obtained from an half full-scale upflow fixed bed reactor (UFBR) treating a primary settled domestic sewage. This study used expanded clay with an effective size of 2.7 mm containing hematite and magnetite as a granular medium.The content of TSS in the effluent treated was always between 10 and 20 mg l⁻¹ for bed depths ranging from 2 to 3 m and filtration rates of 3–6 m³m⁻²h⁻¹.The profiles taken all along the reactor show that the activity of the biomass is constant over the whole height of the reactor. Moreover, an air/water volume ratio of 2:1 is amply sufficient to satisfy the oxygen demand of the biomass. The average removal efficiency based on the soluble COD remains virtually unchanged as a function of the filtration rate at about 70% of the influent. For a final BOD₅ of 30 mg l⁻¹, loadings of 4.5–8 kg BOD₅m⁻³ can be applied. This corresponds to filtration rates of 3–6 m³m⁻²h⁻¹. The removal efficiencies for BOD₅ are then about 80%.After optimization of the backwashing conditions, the consumption of backwash water is about 5% of the volume of filtered water.Sludge measurements carried out during our experiments indicate an excess sludge production of 1 kg kg⁻¹ BOD₅ eliminated. The nature of these sludges is very similar to the biological sludges produced in the high rate activated sludge process.This study has made it possible to establish design parameters of an UFBR and to develop technology for applications. These results are applied to two wastewater treatment plants which began to operate in 1984: these plants serve population equivalents of 40,000 and 11,000.     

MBR在生活污水处理与回用中的应用

阐述了膜生物反应器（MBR）的分类及原理,总结出膜生物反应器较传统的活性污泥系统所具有的特点,重点介绍了膜生物反应器在生活污水处理领域的应用,从而达到较高的去除效果。     

Nutrient removal in a trapezoidal vegetated drainage ditch used to treat primary domestic sewage in a small catchment of the upper Yangtze River

A trapezoidal constructed ditch (TCD) of 300 m length and 2.2 m width was designed and built in the downstream section of the upper Yangtze River for in situ treatment of primary domestic sewage. The removal efficiencies of TN, NH₄‐N, NO₃‐N, TP and PO₄‐P from the TCD were approximately 61, 63, 48, 58 and 51%, respectively. The concentrations of TN, NH₄‐N, NO₃‐N, TP and PO₄‐P showed a decreasing trend with increasing distance downstream. Plant assimilation and sediment retention were the key mechanisms for N and P removal within the TCD, with subsequent microbial uptake and transformation of the nutrients. The TCD outlet showed significantly higher dissolved oxygen (DO) concentrations and lower values of electrical conductivity and total dissolved solids compared to the influent. Results of this study highlight the potential of TCD to mitigate nutrients from primary domestic sewage transported downstream and could be incorporated into local best management practices.     

Distribution of linear alkylbenzenes (LABs) in riverine and coastal environments in South and Southeast Asia

This paper reports the result of sewage pollution monitoring conducted in South and Southeast Asia during 1998-2003 using linear alkylbenzenes (LABs) as molecular tracers of sewage contamination. Eighty-nine water samples collected from Malaysia, Vietnam, and Japan (Tokyo), and 161 surface sediment samples collected from Tokyo, Thailand, Malaysia, Philippines, Vietnam, Cambodia, Indonesia, and India were analyzed for alkylbenzenes. The concentration range of SigmaLABs in river water particles in Southeast Asia (<0.005-0.913 microg/L) was comparable to or higher than those found in Tokyo (<0.005-0.638 microg/L). I/E ratios (a ratio of internal to external isomers of LABs) in tropical Asian waters were close to the value of LABs in raw sewage ( approximately 1) and much lower than those in secondary effluents (3-5). This suggests that untreated or inadequately treated sewage is discharged into the water. SigmaLABs concentrations in sediments from South and Southeast Asia ranged from <0.002-42.6 microg/g-dry with the highest concentration occurring at several populous cities. Low I/E ratios of the sediments with high SigmaLABs concentrations suggest a heavy load of untreated sewage. Clearly in view of the current data and evidence of the implications of sewage pollution, this paper highlights the necessity of the continuation of water treatment system improvement in tropical Asia.     

Acetoacetic acid as a potential trihalomethane precursor in the biodegradation intermediates produced by sewage bacteria

When sodium linear dodecylbenzenesulfonate (LAS), sodium dodecylsulfate (AS) and glucose were incubated with sewage bacteria, a high level of chloroform was produced on chlorination in the course of biodegradation. In addition to LAS, AS and glucose, the primary biodegradation intermediates of LAS and AS were not able to produce high level of chloroform. Acetoacetic acid was found to produce a large quantity of chloroform on chlorination amounting to 55.5% on a molar basis. The formation of acetoacetic acid in the course of biodegradation was determined and it was found that from 51 to 87% of the total chloroform produced could be explained to be derived from acetoacetic acid. These results indicate that acetoacetic acid functions as a potential chloroform precursor in the biodegradation of organic materials by sewage bacteria.     

Identification of viruses isolated from sewage,riverwater and coastal seawater in Barcelona

In a virological survey carried out in Barcelona, enteric viruses were isolated in samples from a sewage outlet (90% positive isolations), from two rivers (92 and 80% positive isolations) and from three beaches (17, 17 and 8% positive isolations). Viral identifications revealed that Poliovirus was detected in all kinds of water under study, the prevalent strain being vaccine type 3.     

The determination of cadmium. lead, copper and zinc in ground water, estuarine water, sewage and sewage effluent by anodic stripping voltammetry

Anodic stripping voltammetry (ASV) using the thin-film mercury electrode was shown to be a successful technique for the determination of total (free plus complexed) trace metal concentrations in various types of aqueous sample. The method developed involved the minimum of sample treatment and required only simple and inexpensive equipment. The practical limit of sensitivity was about 0·1 μg I⁻¹ for cadmium, lead and copper. The determination of zinc was found to be complicated by the formation of an intermetallic compound with copper. Interference by other trace metals and by complexing agents was investigated. Photochemical oxidation for the decomposition of complexes of the metals with organic ligands in filtered sewage and sewage effluent was found to be successful, although the process is slower for cadmium than for the other metals. Good agreement with atomic absorption spectroscopy was obtained for all the types of aqueous sample investigated. Possible improvements of the ASV technique are discussed.     

Development and validation of a drinking water temperature model in domestic drinking water supply systems

Domestic drinking water supply systems (DDWSs) are the final step in the delivery of drinking water to consumers. Temperature is one of the rate-controlling parameters for many chemical and microbiological processes and is, therefore, considered as a surrogate parameter for water quality processes. In this study, a mathematical model is presented that predicts temperature dynamics of the drinking water in DDWSs. A full-scale DDWS resembling a conventional system was built and run according to one year of stochastic demands with a time step of 10 s. The drinking water temperature was measured at each point-of-use in the systems and the data-set was used for model validation. The temperature model adequately reproduced the temperature profiles, both in cold and hot water lines, in the full-scale DDWS. The model showed that inlet water temperature and ambient temperature have a large effect on the water temperature in the DDWSs.     

天津市某污水处理及再生水利用工程设计探讨

结合GB 18918-2002城镇污水处理厂污染物排放标准,对天津市某污水处理及再生水利用工程设计进行了探讨,分别阐述了具体处理工艺及相关设计参数,并归纳了该设计方案中的节能措施,以指导今后同类工程项目。     

The relative importance of Lemna gibba L., bacteria and algae for the nitrogen and phosphorus removal in duckweed-covered domestic wastewater

To arrive at detailed nutrient balances for duckweed-covered wastewater treatment systems, five laboratory-scale experiments were carried out in shallow (3.3 cm), 1 l batch systems to assess separately the contributions of duckweed itself, attached and suspended bacteria as well as algae to N- and P-removal in domestic wastewater. Depending on the initial concentrations, our duckweed-covered systems removed 120–590 mg N m⁻² d⁻¹ (73–97% of the initial Kjeldahl-nitrogen) and 14–74 mg P m⁻² d⁻¹ (63–99% of the initial total phosphorus) in 3 days. Duckweed (Lemna gibba L.) itself was directly responsible for 30–47% of the total N-loss by uptake of ammonium and, probably dependent on the initial P-concentrations, for up to 52% of the total P-loss. The indirect contribution of duckweed to the total nutrient removal was also considerable and included the uptake (and adsorption) of ammonium and ortho-phosphate by algae and bacteria in the attached biofilm and the removal of N through nitrification/denitrification by bacteria attached to the duckweed. Together these accounted for 35–46 and 31–71% of the total N- and P-loss, respectively. Therefore, approximately of the total N- and P-loss could be attributed to the duckweed mat. The remaining quarter is due to non-duckweed related components: uptake and nitrification/denitrification by algae and bacteria attached to the walls and the sediment of the system (including sedimentation). Other processes, like NH₃-volatilisation, N-fixation and nutrient uptake as well as nitrification/denitrification by suspended microorganisms did not influence the N- and P-balance of our systems, but could become important with increasing water depths and retention times.     

Glucose mineralization activity and the use of the heterotrophic activity method in an acidified lake

This paper concerns bacterial glucose mineralization in Silver Lake sampled during the summer; specifically, whether or not it occurs, and whether or not the “heterotrophic activity method” can be used to measure it, in this acidified lake.For Sampling I, linearity between turnover time (t/f) and added substrate concentration (A) did not exist at the in situ pH (3.2) or the experimental pH's (5.5 and 7.0), even though time studies showed that glucose was being mineralized at measurable rates. For Sampling II, modifications were made to the concentrations of labelled glucose and the incubation time. A highly significant linear relationship between t/f and A was demonstrated, and the turnover time and V_max were calculated to be 472.3 h and 0.005 μm l⁻¹ h⁻¹, respectively. For Sampling III, even though the environmental conditions were similar to those for the previous sampling, a statistically-significant relationship between t/f and A did not result.     

Distribution and potential significance of a gull fecal marker in urban coastal and riverine areas of southern Ontario, Canada

To better understand the distribution of gull fecal contamination in urban areas of southern Ontario, we used gull-specific PCR and qPCR assays against 1309 water samples collected from 15 urban coastal and riverine locations during 2007. Approximately, 58% of the water samples tested positive for the gull-assay. Locations observed to have higher numbers of gulls and their fecal droppings had a higher frequency of occurrence of the gull marker and a higher gull marker qPCR signal than areas observed to be less impacted by gulls. Lower gull marker occurrence and lower qPCR signals were associated with municipal wastewater (7.4%) and urban stormwater effluents (29.5%). Overall, there were no statistically significant differences in gull marker occurrence at beach sites for pore water, ankle, and chest-depth samples, although signals were generally higher in interstitial beach sand pore water and ankle-depth water than in chest-depth water samples. Overall, the results indicated that gull fecal pollution is widespread in urban coastal and riverine areas in southern Ontario and that it significantly contributes to fecal indicator bacterial loads.     

Detection of enteric viruses in municipal sewage sludge by a combination of the enzymatic virus elution method and RT-PCR

Pathogenic enteric viruses can be retained in municipal sewage sludge as has been reported by many researchers. Although the RT-PCR technique has been extensively employed for the virus detection from various environmental samples, the application of RT-PCR to the detection of viruses in sewage sludge has the difficulty because of inhibitory substances to the gene amplification. However, a combination of the enzymatic virus elution (EVE) method with RT-PCR made it possible to effectively detect viruses in sewage sludge. The enzymatic breakdown of sludge flocs in the EVE method enhanced the virus elution from poliovirus 1 (PV1)-inoculated sewage sludge, and the detection of PV1 was performed by RT-PCR without any inhibitions. On the contrary, the application of RT-PCR to the viral assay in the US EPA method using the 10% beef extract solution was not practical because of inhibitions to the viral gene amplification. The combination of the EVE method using lysozyme (polysaccharide-degrading enzyme), papain (protease), and chymotrypsin (protease) with RT-PCR resulted in a virus recovery efficiency of 31%, but a synergistic effect of these enzymes on the virus recovery efficiency was not observed. The EVE method using lysozyme or papain could be a promising procedure for the virus elution from sewage sludge in detecting these viruses with RT-PCR.     

GBInSAR 技术及其在水利工程中的应用

研究了基于地基合成孔径雷达干涉测量（ Ground Based InSAR,GBInSAR）技术的微变形监测系统（ IBIS-L）关键技术和精度,并分析了该系统在紫平铺大坝和泰西纳（ Tessina）滑坡区的监测实例,实践表明该系统具有长期连续监测、覆盖范围广、监测精度高的优点,为水利工程变形监测提供了新方法。     

Coliphages as an indicator of faecal pollution in water. Its relationship with indicator and pathogenic microorganisms

The study was designed to test the proposal that Escherichia coli specific bacteriophages might serve as universal faecal pollution indicators in water. A highly specific, sensitive and rapid technique for the detection and quantification of these virus particles was developed. The numerical relationship between E. coli and its parasitic phages was investigated in three different aqueous ecosystems such as sea water in the vicinity of sewage outfalls, river water contaminated by domestic and industrial sewage discharges, and estuarine waters, and found to be very close. In addition, the results obtained indicate that the coliphages are good indicators of the presence of the pathogenic microorganisms studied. In nearly all the water samples tested, the results suggest that coliphages are better indicators of faecal pollution than the classical indicator systems currently employed.     

The accumulation of La,Ce and Y by Lemna minor and Lemna gibba in the Keban gallery water,Elazig Turkey

This study investigated the phytoremediation ability of Lemna minor and Lemna gibba to accumulate lanthanum, cerium and yttrium from gallery water polluted by metals. L. minor and L. gibba were settled in the mining water and adapted to separate reactors. During the experiment, the water and plant samples were daily taken and the temperature, electric conductivity and pH of the water were daily measured in situ. These plants were firstly washed, dried in and then ashed at 300°C for 24 h in an oven. Both water and ashed plant samples were measured by ICP‐MS to detect the concentrations of lanthanum (La), cerium (Ce) and yttrium (Y). Although these elements are at low concentrations in gallery water, they were accumulated at the highest levels in L. gibba and in L. minor. This study showed that both plants have high ability to remove lanthanum, cerium and yttrium in gallery water polluted by different elements.     

运砖车蓄电池的使用、维护与故障分析

砖厂运砖车一般采用农用车或小型装载机,不管是哪种车辆,蓄电池是不可缺少的装置,其工作状况的优劣直接影响车上电气系统以及电控装置的性能。运砖车大都使用铅酸蓄电池,它具有电动势高、     

Sorbic acid as a quantitative probe for the formation, scavenging and steady-state concentrations of the triplet-excited state of organic compounds

Sorbic acid (trans,trans-hexadienoic acid) was developed as a probe for the quantification of the formation rate, overall solution scavenging rate and steady-state concentrations of triplet-excited states of organic compounds. The method was validated against literature data for the quenching rate constant of triplet benzophenone by tyrosine obtained by laser flash photolysis and by Stern-Volmer plots of phosphorescence quenching. In contrast to these methods, the probe method does not require knowledge of the optical properties of triplets to monitor their quenching. Moreover, the probe method permits simultaneous quantification of triplet formation, quenching and steady-state concentrations during illumination of complex chromophore mixtures, such as natural organic matter (NOM), with polychromatic light >315 nm. Application of the method to de-aerated Suwannee River NOM illuminated with polychromatic light (315-430 nm) resulted in a triplet quantum yield of 0.062.