不同曝气位置曝气生物滤池（BAF）处理对虾养殖污水的试验研究

采用不同曝气位置的上向流生物滤池处理对虾养殖污水,连续运行30d,分析出水水质,并观察系统运行情况和装置污染状况。考察了对虾养殖污水中化学需氧量、氨氮、硝酸盐氮、亚硝酸盐氮、无机氮及活性磷酸盐6项指标的去除效果。结果表明：从养殖污水主要污染物指标的去除效果上看,中下部曝气生物滤池（MUBAF）要优于底部曝气生物滤池（BUBAF）。在系统进水化学需氧量质量浓度为7.62～8.20mg·L-1,氨氮质量浓度为0.62～0.65mg·L-1,硝酸盐氮质量浓度为0.54～0.59mg·L-1,亚硝酸盐氮质量浓度为0.23～0.27mg·L-1,无机氮质量浓度为1.40～1.47mg·L-1,活性磷酸盐质量浓度为0.24～0.29mg·L-1,水温为25℃～30℃时,中下部曝气生物滤池对养殖污水中6项指标的去除率分别为45.2%、88.9%、58.5%、78.8%、75.3%和25.1%。可见,对氨氮的去除效果最佳,亚硝酸盐氮和无机氮次之,化学需氧量和硝酸盐氮的去除效果较差,活性磷酸盐去除率最低。总体而言,曝气生物滤池在水产养殖污水应用中处理效果明显,具有可行性和实用性。     

Assessment of Luffa cylindrica as Support in Biofilms Reactors for the Biological Treatment of Domestic Wastewater

A simultaneous treatment of BOD, phosphorous and ammonia in artificial wastewater was carried out in biofilm reactors with Luffa cylíndrica as organic support and compared with PVC's support under variations of dissolved oxygen of 1.5 a 3.0 mg l^?1 in the same reactor. During semicontinous treatment, the removal of BOD (92.5%) with Luffa cilíndrica was higher than PVC support (80%). Nitrification only existed at levels of oxygen of 3 mg l^?1, showed in the effluent a final concentration of ammonium of 17 and 19 mg l^?1 for Luffa cilíndrica and PVC support, respectively. In reactors with Luffa cilíndrica a higher percentage of P removal (40%) was reached, while no elimination in reactors with PVC was observed. The formation of anaerobic-aerobic zones inside the natural support probably allowed the increase in the efficiency of removal of phosphorous. Oxidation of organic matter, P removal and nitrification can be achieved with the variation of oxygen inside of the same biofilm reactor using L. cylindrical as support material.     

荸荠秆枯病菌生物学性状研究

荸荠秆枯菌（ＣｙｌｉｎｄｒｏｓｐｏｒｉｕｍｅｌｅｏｃｈａｒｉｄｉｓＬｅｎｔｚ）生长发育温度８～３５℃，最适于菌丝体生长、产孢的温度为２５～３０℃，２０～２８℃孢子萌芽率较高。致死温度４６℃１０ｍｉｎ。病菌在ＲＨ７５％以上生长良好，其产孢量则随湿度升高而增加。ＲＨ８１％以上孢子可以发芽，饱和湿度再加水滴时发芽率最高。ＰＨ４．５０～９．１３均较适于病菌生长，产孢量则以在ＰＨ６．９４～９．１３时较多，ＰＨ４．２０～７．６０较适宜孢子发芽。连续黑光灯照射有促进孢子形成和菌丝体旺盛生长的作用。此菌对多种单糖、双糖和多糖都能利用，以蜜二糖、麦芽糖、葡萄糖等产孢量较多。适于病菌生长和产孢的氮源是甘氨酸、ＤＬ－α－氨基丙酸和氨基乙酸，脲素较差。     

Biological Degradation and Chemical Oxidation Characteristics of Coke-Oven Wastewater

Biological and chemical oxidation characteristics of two kinds ofcoke-oven wastewaters, A and B, discharged from a conventional batch coke-oven and a newly developed continuous coke-oven, respectively, were studied for selecting effective treatment processes of the wastewaters. Pollutants contained in Wastewater-A could be removed by biological process with a sufficient effluent quality, while those which existed in Wastewater-Bcould not be satisfactorily removed. Microbial community structure investigation using the respiratory quinone profile clarified that Pseudomonas putida (dominant quinone: ubiquinone-9) was a dominant species in the biological treatmentsystem. The refractory organic pollutants, existed in Wastewater-B,were mineralized more effectively by Fenton's reagent than by ozone. A wastewater treatment process, in which Fenton's oxidation is followed by a biological treatment, was proposed forthe treatment of Wastewater-B based on the experimental results.     

Biological Processing Capacities and Biomass Growth in Waste Water Treatment by Infiltration On two Kinds of Sand

In this article, work is presented which highlights the biological processing capacities of urban waste water within porous media of different textures. A comparative study on the growth of biomass coupled with the general mechanisms for gas transfer through two biological beds is undertaken. Infiltration-percolation beds are simulated using columns filled with sands of different origins and structures. These are periodically fed using an influent with a COD load of 525 mg/l and 54 mg/l of Kjeldahl nitrogen. The results obtained show that a balanced development of biomass, including growth and regression phases, is intrinsically related to the physical nature of the material support. Using core samples from the columns and oxymetry probes set at various heights, it is shown that both the vertical distribution of the biofilm in the columns and oxygenation of the porous media during a rest period also correlate with the support structure. The effectiveness of biological treatment is optimum for carbon with alluvial sand rather than crushed sand, with this tendency being significantly reversed for nitrogen abatement.     

Operational Optimisation of Pilot Scale Biological Nutrient Removal at the Ciudad Real (Spain) Domestic Wastewater Treatment Plant

The aim of this work is optimising operating conditions for a possibleimplementation of a Biological Nutrient Removal (BNR) process in the Wastewater Treatment Plant (WWTP) of Ciudad Real (Spain). Several factors (hydraulic retention times, anaerobic nitrate concentration, sludge age and wastewater biodegradability) were tested using a pilot scale VIP (Virginia Initiative Plant) activated sludge process and domestic wastewater from the full scale plant. Hydraulic retention times used did not cause changes in N and P removal. P removal was adversely affected by anaerobic NO₃ ^- and improved with higher BOD₅/COD ratios in wastewater. Influence of sludge age was very low in P removal, but N removal was mainly affected by this factor. Final operating conditions were selected taking into account their effects over one of both nutrients. COD and SS removal were always successful. N removal was also easily reached and the main difficulty was P removal. P sludge content was very low (2.5–4%) approximately and was also affected by the same factors tested. The main factor to improve P removal was supposed to be the organic wastewater composition. Wastewater characteristics were modified by using different sources from the WWTP. Volatile fatty acids (VFA) addition to the wastewater by using supernatant of the anaerobic sludge digesters seemed to be the best practical solution for a future BNR implementation in the WWTP.     

Enhancement of Biological Nitrogen Removal from Wastewater by Low-Intensity Ultrasound

This paper investigated the influence of low-intensity ultrasound in biological nitrification and denitrification. The results showed that the nitrification activity of activated sludge could not be promoted significantly by ultrasound in 5–40 min with intensities ranging from 0.1 to 1.2 W?cm^?2. It suggested the fact that nitrifying bacteria were insensitive to ultrasound, possibly related with their specific structures of cell membrane and ways of metabolism. Whereas, biological denitrification was enhanced quite remarkably by ultrasound and the optimal results were achieved at the ultrasonic intensity of 0.2 W?cm^?2 and the irradiation time of 10 min. Compared with the control without ultrasonic irradiation, it took 5 h for the enhancement of denitrification rates induced by the optimum ultrasound to reach its peak level (16%). Therefore, ultrasound with intensity of 0.2 W?cm^?2 could be employed in the biological denitrification system for 10 min every 5 h to obtain the optimal effect theoretically.     

Ecological Engineering of Bioreactors for Wastewater Treatment

Biological nutrient removal (BNR) systems remove carbon, nitrogen, and phosphorus from wastewaters through biodegradation of organic compounds, oxidation of ammonia-N to nitrate-N, reduction of nitrate-N to N₂ gas, and sequestration of phosphorus as polyphosphate. The microbial community in such systems is complex because it must contain heterotrophic bacteria capable of aerobic respiration, anaerobic respiration, and fermentation; specialized heterotrophic bacteria that can store polyphosphate; and autotrophic nitrifying bacteria that can withstand long periods without oxygen. Although the basic design principles for BNR systems are reasonably well established, it is becoming apparent that a greater understanding of the microbial interactions involved is required to increase system reliability. For example, although the environment established for the selection of phosphorus accumulating organisms was thought to give them a strong competitive advantage over other heterotrophic bacteria, this has turned out not to be the case. Rather, glycogen accumulating organisms can compete quite effectively in the same environment. Furthermore, BNR systems have suffered from problems with sludge settleability, even though many of the system characteristics are considered to be conducive to the suppression of filamentous bacteria. Finally, the use of molecular techniques has revealed that the autotrophic nitrifying bacteria are different from those that had been considered to be present. This paper reviews the microbial ecology of BNR systems, establishes how molecular biology techniques are changing our understanding of that ecology, and suggests ways in which engineering control can be exerted over community structure, thereby increasing the reliability of BNR systems.     

厌氧—好氧处理垃圾浸出污水装置的试验研究

采用厌氧好氧生物氧化技术设计和制造了一套与工艺流程相一致的处理垃圾物浸出污水的模拟装置。该装置用有机玻璃为主要材料,便于观察处理池内污水流向、色泽变化及污泥增长情况。经这种装置处理后的污水,基本可达到国家农田灌溉的污水排放标准和国家三类废水排放标准。试验结果表明,该装置处理垃圾浸出污水效果良好。     

Biofilm Airlift Suspension Reactor Treatment of Domestic Wastewater

Domestic wastewater with an influent COD of 160 to 327 mg L^-1 was evaluated for treatment by the Biofilm Airlift Suspension-reactor (BAS-reactor). Ceramic materials withdiameters of 0.25–0.5 mm (for reactor (1)) and 0.5–0.71 mm(for reactor (2)) were used as carriers, respectively. Theresults show that reactor (1) with smaller carriers outperformedreactor (2) with larger carriers. At steady state, the BAS-reactors showed high COD removal efficiencies. When the HRT was kept at 0.5 hr, the mean effluent CODs were 33±4 and 58±5 mg L^-1 for reactors (1) and (2), respectively, at a confidence interval of 95% (p = 95%). When HRT was extended to 1.0 hr, these values decreased to 24±2 and 30±3 mg L^-1 for reactors (1) and (2), respectively (p = 95%). Biomass concentration increased whilebiofilm thickness decreased with an increase in carrierconcentration. Biomass concentrations as high as 6.16±0.12 and 5.50±0.10 g VSS L^-1 (p = 0.95) were achieved at carrier concentrations of 100 g L^-1 forreactors (1) and (2), respectively. Biofilm thickness had a significanteffect on reactor performance: with an increase in biofilm thickness, biomass concentration increased and the critical gas velocity to maintain carrier fluidization decreased. An oxygenation model for a BAS-reactor was proposed and the effectsof gas velocity and carrier concentration on the oxygen transfercoefficient were examined. It was found that oxygen transfer coefficient increased with gas velocity while the relationship between carrier concentration and oxygen transfer coefficient wascomplicated. During a period of more than three months of steadystate operation, carrier washout with the effluent was negligible.Comparison of the parameters of the conventional activated sludgeprocess to that of the BAS-reactor shows that the BAS-reactor isa promising wastewater treatment process with high efficiency andlow operation cost.     

Ciprofloxacin Resistance in Domestic Wastewater Treatment Plants

The potential of domestic wastewater treatment plants to contribute for the dissemination of ciprofloxacin-resistant bacteria was assessed. Differences on bacterial counts and percentage of resistance in the raw wastewater could not be explained on basis of the size of the plant or demographic characteristics of population served. In contrast, the treated effluent of the larger plants had significantly more heterotrophs and enterobacteria, including ciprofloxacin-resistant organisms, than the smaller (p?<?0.01). Moreover, longer hydraulic retention times were associated with significantly higher percentages of resistant enterobacteria in the treated effluent (p?<?0.05). Independently of the size or type of treatment used, domestic wastewater treatment plants discharged per day at least 10¹⁰–10¹⁴ colony forming units of ciprofloxacin-resistant bacteria into the receiving environment.     

Volatile Organic Contaminant Emissions from Wastewater Treatment Plants During Secondary Treatment

Volatile organic contaminant (VOC) emissions from wastewater treatment plants may occur through a variety of mechanisms which mainly include volatilization, evaporation, biodegradation, and photodecomposition. A mathematical model incorporating the significant factors affecting VOC emissions from a secondary treatment facilities has been developed and verified with the operational data from wastewater treatment plant in south Florida. The model includes mass transfer considerations for volatilization from clarifier surfaces and weirs, in addition to volatilization from aeration basins. A simple model such as this one can be a useful tool to estimate VOC emissions from municipal wastewater treatment plants and to evaluate the present and future state of compliance with applicable air quality standards.     

Biological Denitrification of High Nitrate Processing Wastewaters from Explosives Production Plant

Wastewater samples originating from an explosives production plant (3,000 mg N l⁻¹ nitrate, 4.8 mg l⁻¹ nitroglycerin, 1.9 mg l⁻¹ nitroglycol and 1,200 mg l⁻¹ chemical oxygen demand) were subjected to biological purification. An attempt to completely remove nitrate and to decrease the chemical oxygen demand was carried out under anaerobic conditions. A soil isolated microbial consortium capable of biodegrading various organic compounds and reduce nitrate to atmospheric nitrogen under anaerobic conditions was used. Complete removal of nitrates with simultaneous elimination of nitroglycerin and ethylene glycol dinitrate (nitroglycol) was achieved as a result of the conducted research. Specific nitrate reduction rate was estimated at 12.3 mg N g⁻¹ VSS h⁻¹. Toxicity of wastewater samples during the denitrification process was studied by measuring the activity of dehydrogenases in the activated sludge. Mutagenicity was determined by employing the Ames test. The maximum mutagenic activity did not exceed 0.5. The obtained results suggest that the studied wastewater samples did not exhibit mutagenic properties.     

Natural Diffusers for the Treatment of Residual Water in an Aerobic System

The adsorption capacity of vermiculite, a natural clay, for removing dibenzothiphene (DBTP) from water solutions was investigated. DBTP is an organic compound with sulfur, commonly found in fossil fuels and coal. This compound can also be found in the environment due accidental spills of oil and derivatives. Due to its structure and physical–chemical properties it is considered a persistent compound. Vermiculite (VT) was used as an adsorbent in its natural form, impregnated with copper ions (Cu-VT), and hydrophobically modified (HDTMA-VT) by replacement sodium cations by hexadecyltrimethyl ammonium ion. The results showed that DBTP was adsorbed in considerable amounts by HDTMA-VT; however, the Cu-VT adsorbed DBTP in some proportions of HDTMA-VT. Because of the presence of sulfur atoms in the structure of the molecule, π complexation can be observed. The adsorption isotherms were treated by the Freundlich equation. The values of K _f are similar to Cu-VT and HDTMA-VT, showing that the adsorption may be either through hydrophobic interactions or interactions through the formation of π complex. Meanwhile, the results with the VT (natural form) showed a much smaller value of K _f. It is believed, compared with the literature, and because of the chemical composition of the vermiculite, that the adsorption mechanism is also conducted by π complexation, considering the absence of organic carbon content.     

Evaluation of some Methods for Fish Canning Wastewater Treatment

A fish canning facility processes 1900–2000 tons of mackerel and sardine annually at arate of 10–15 tons per day for a total of 200 days yr^-1. This factory generates an average of 20 m³ of industrial wastewaters per day. The objective of our study, which was carried out on a bimonthly basisfrom December 1995 to November 1996, was to determine the overall pollutant load associated with this effluent in relation to the applicable Egyptian Standards and to propose methods for pollutant load reduction before discharging it to the local sewer. The methods were to benefit through the recovery of wasted organic load and transform it into an environmentally safe residue amenable for either immediate reuse or final disposal thereafter. Five chemical coagulation/flocculation treatments were tried using ferric chloride, alum, lime, ferric chloride and lime, and alum and lime. The best method involved the use of FeCl₃ and Ca(OH)₂ (0.4 g Fe L^-1 and 0.2 g Ca L^-1, respectively) which reduced the average influent BOD₅ from 989 to 204 mg L^-1, the COD from 1324 to 320 mg L^-1, TSS from 4485 to 206 mg L^-1, total protein content from 812 to 66 mg L^-1 and oil and grease from 320 to 66 mg L^-1. The separated dried precipitate averaged 50 g L^-1 which was found to contain 40% by weight recovered protein and 20% recovered fat. The solid was ideal for on-site reprocessing as animal feed. As well, the final effluent, if not discharged to the area sewer, was safe for controlled use in some irrigation applications or forestry projects at the desert area surrounding the factory.     

Removal Processes for Tributyltin During Municipal Wastewater Treatment

Water, Air, &; Soil Pollution - The fate and behaviour of tributyltin (TBT) at two wastewater treatment works was examined. Both sites had two inlet streams, and each utilised high rate...