Kurzzeitermittlung der Ablaufqualität von Belebtschlammanlagen anhand der Atmungsaktivität

For checking the quality of the effluent from an activated sludge plant for waste-waters from the sulphite pulp production the respiration of an activated sludge sample in air-saturated water is determined initially without the addition of substrate (ground respiration) and after that with an addition of substrate (methanol, substrate respiration) by means of the Clark-electrode. The measuring device is designed by means of zero displacement in such a way that the difference of the oxygen concentration is indicated by a time relay as the difference quotient. Between the ground respiration and the effluent concentration of BOD₅ exists a significant positive regression, which can be used for controlling the plant. The determination of the substrate respiration serves only for checking with respect to perhaps given inhibition of the conversion of matter by the activated sludge. The determination of the activity of the activated sludge sample takes only 20 min; inclusive of the required determination of the dry matter of sludge, the technique provides a well reproducible measured value for the biochemical conversion in the activated sludge plant within 1… 1.5 h.     

Optimierung des Belebungsverfahrens durch Minimierung des Volumens von Belebungs- und Nachklärbecken

The separate examination of the processes of the settling and thickening of activated sludge allows us to minimize the volumes of aeration tanks and final clarification tanks. The following initial quantities are given: wastewater quantity, inflow and outflow concentrations of BOD₅, wastewater temperature and reflux ratio of activated sludge and, in addition, three parameters of the thickening behaviour of activated sludge as well as a parameter for the bioactivity of sludge, which are to be determined in an experimental plant. From this, the optimum concentration of the activated sludge in the aeration tank is calculated at which the total of volumes for aeration tank and final clarification tank becomes a minimum. The process is carried out numerically by an example.     

Studies on the Behaviour of Water-endangering Substances in Plants for the Biological Cleaning of Municipal Waste Waters. Part 1: Bromoxynil

The behaviour of the herbicide bromoxynil (3,5-dibromo-4-hydroxybenzonitrile), labelled with ⁸²Br, is investigated in an activated sludge plant on the laboratory scale with municipal wastewater. Only 5% of bromoxynil present in a concentration of 5 mg/l are degraded after preadaption of activated sludge for some weeks. The known hydrolysis products 3,5-dibromo-4-hydroxybenzamide and 3,5-dibromo-4-hydroxybenzoic acid were identified as degradation products. In addition, 1.9±0.9% of the quantity of ⁸²Br appeared in the solution as Br^? by debromination. Moreover, a pronounced adsorption of the active substance on activated sludge occurs. Its activity amounts to about 130% of the initial activity of the solution.     

Bestimmung der Aktivität von Belebtschlamm über die Geschwindigkeit der Biosynthese von Aminopeptidasen

The authors describe a possibility of a fast determination of the metabolic activity of various activated sludge samples. There is not used the sludge property of digestion, but the biosynthesis of aminopeptidases. Egg albumin has been found to be the optimum standard indicator. The activity of the investigated activated sludge is derived from the rate of the biosynthesis of aminopeptidases. The technique proposed can be used also for determining the toxic effects of different substances on activated sludge.     

The Growth of Micromycetes in Activated Sludge Media

Today already numerous micromycetes are a recognized part of the biocenosis of growth in receiving waters strongly polluted by organically rich waste waters and of growth on biofilter media surfaces. The principal representatives are some Deuteromycetes, Mucorales and Saccharomycetaceae, whereas the so-called true aquatic fungi (Oomycetes) with the exception of Leptomitus lacteus are practically absent. The growth of micromycetes in activated sludge remains still an unanswered question. Generally, the filaments in the activated sludge are ascribed to filamentous bacteria and as long as fungi were isolated from activated sludge their presence has been reported only in the form of spores. The nitrogen deficiency with regard to carbon present in the waste water is considered as one of the factors enhancing the development of fungi in the activated sludge. In a series of 13 tests carried out on laboratory-scale batch models using synthetic waste water, where the carbon source was glucose and the nitrogen source was (a) sodium nitrate, (b) ammonium sulphate, and (c) peptone, the fungal growth was studied in different models with the BOD:N ratio varying from 20 to 1000. The models were seeded with thickened activated sludge from the municipal sewage works. The sludge did not contain any microscopically detectable forms of fungoid growth. It was found that the fungi in activated-sludge medium grow well and both in the forms of single cells, occuring independently and in chains, as well as in the form of long branched filaments. In some instances, the micromycetes formed up to 80 to 100 per cent of the biocenosis of the activated-sludge flocs, but the dependency of their development on the increasing BOD:N ratios in the waste water has not been ascertained. Fifteen species of micromycetes were isolated and identified, and in addition several representatives of Saccharomycetaceae, which were not identified.     

Bio-augmented activated sludge treatment of potato wastewaters

A laboratory study was conducted to determine the effect of bacterial augmentation with LLMO (liquid live microorganisms) on the activated sludge treatment of potato wastewaters. Completed mixed activated sludge bench scale reactors were used in this study. Parameters varied during the continuous reactor run included hydraulic detention time, LLMO addition, and powdered activated carbon addition. The hydraulic detention time lasted 1, 2, and 3 days, while the sludge age was maintained at 10 days for both reactors. The bio-augmented reactor had a better COD removal than the non-bio-augmented reactor at a lower MLVSS level in the reactor. It is concluded that bacterial augmentation with LLMO improved slightly the COD removal efficiency in treating potato wastewaters with the activated sludge process. The bio-augmentation increased the substrate removal rate, increased the oxygen utilization, and decreased the excess sludge production.     

The role and significance of extracellular polymers in activated sludge. Part I: Literature review

In biological wastewater treatment, bacteria tend to aggregate by forming flocs, biofilms and even granules. A large part of the floc structure in activated sludge is composed of extracellular polymers. The extracellular polymeric substances (EPS) are mainly responsible for the structural and functional integrity of biofilms/flocs and they are considered to be important for the physico‐chemical properties of activated sludge. This review considers the composition of EPS and proportion between the constituents. Moreover it includes the relationship between the EPS constituents and sludge properties such as sludge retention time, hydrophobicity and surface charge.     

Fate of Lignin in the Process of Aerobic Biological Treatment of Paper Mill Wastewater

Although lignin is known to be not readily biodegradable the concentration of dissolved lignin decreased during aerobic biological treatment of paper mill wastewater performed in sequencing batch reactors (SBR). Systematic lab scale batch tests were conducted to clarify whether the observed removal of lignin was the result of biodegradation or adsorption onto the activated sludge. For the batch tests, sludge samples were taken from sequencing batch reactors operated at solid retention times (SRT) of 10, 15, 20, 30, and 40 days, respectively. The amount of lignin present in the bulk liquid and in the sludge samples was quantified by an analytical procedure comprising pyrolysis, gas chromatography and mass spectrometry (py‐GC/MS analysis). It was found that lignin adsorbs onto the activated sludge by up to 30%[TH]w/w. This demonstrates the sludge excellent adsorption properties. The ultimate removal of lignin is achieved by sludge wasting. The highest overall removal rate was found when sludge was used from the SBR run at SRT of 20 days.     

Sequencing Batch Experiments with activated Sludge Consuming Glucose and Phenol

During the rather short solids retention time θ = 1.25 d phenol is not utilized by activated sludge and only glucose is consumed during the sequencing batch experiments. After glucose consumption the residual COD concentration (COD = 820 mg/l) is represented mainly by the phenol concentration. During the rather long solids retention time θ = 8 d phenol is consumed by activated sludge as well as glucose. In this case the residual COD concentration is much smaller (COD = 46 mg/l) and the ratio BOD₅/COD = 0.1 is small, too. The general model of biological treatment suggested by one the authors earlier can describe the sequencing batch experimental data rather well.     

Biokinetics of Nitrification in the Activated Sludge Process with Bioaugmentation

A laboratory study was conducted to determine the effect of bioaugmentation on nitrification performance in activated sludge process for treating municipal wastewaters. Two continuous flow bench-scale activated sludge systems consisting of 3 reactors each were operated for 30 months. The bacterial culture product used in bioaugmentation contained supplementary heterotrophic and nitrifying microorganisms. Parameters investigated included wastewater strength, hydraulic detention time, and sludge age in an activated sludge reactor system, which were low, medium and high strength; 6, 12, and 24 hours detention time; and 5, 10, and 20 days sludge age. A first reaction order mathematical model was developed for the nitrification process. Statistical fitting of the experimental data to the mathematical model allowed for determination of nitrification rate constant, decay coefficients, minimum aeration time required for initiation of the nitrification process, and the ability of the system to perform nitrification for the applied operation conditions. The results indicated that bioaugmentation improved nitrification at higher influent strength and at longer sludge age, did initiate nitrification earlier in the reactors, and did not affect the nitrification rate nor the decay coefficients.     

The Influence of the Concentration of Dissolved Oxygen on the Determination of the Dehydrogenase Activity of Activated Sludge Using the Method of TTC Test

Due to its oxidation-reduction potential, oxygen occurs in the TTC test for the determination of the dehydrogenase activity as a competitive hydrogen acceptor. At different oxygen concentrations in the solution to be tested and also at varying rates of oxygen depletion, e.g. in activated sludge samples, thus the formazan formation from TTC shows differences. Under similar anaerobic conditions, the test results of the dehydrogenase activity are higher in most cases and show a smaller range of variation than under aerobic conditions. The importance of the oxygen concentration is demonstrated in investigations with activated sludge, anaerobic conditions being set by addition of Na₂SO₃.     

Cd(II), Pb(II) and Zn(II) Removal from Contaminated Water by Biosorption Using Activated Sludge Biomass

Biosorption using activated sludge biomass (ASB) as a potentially sustainable technology for the treatment of wastewater containing different metal ions (Cd(II), Pb(II) and Zn(II)) was investigated. ASB metal uptake clearly competed with protons consumed by microbial biomass compared with control tests with non‐activated sludge biomass. Biosorption tests confirmed maximum exchange between metal ions and protons at pH 2.0–4.5. It was revealed by the study that the amount of metal ions released from the biomass increased with biomass sludge concentration. The result showed that maximum absorption of metal ions was observed for Cd(II) at pH 3.5, Pb(II) at pH 4.0, and pH 4.5 for Zn(II) ions. The maximum absorption capacities of ASB for Cd(II), Pb(II) and Zn(II) were determined to be 59.3, 68.5 and 86.5%, respectively. The biosorption of heavy metals was directly proportional to ASB stabilization corresponding to a reduction in heavy metals in the order of Cd < Pb < Zn. The order of increase of biosorption of metal ions in ASB was Zn(II) < Pb(II) < Cd(II), and this was opposite to that of non active sludge. The results indicate that ASB is a sustainable tools for the bioremediation of Cd(II), Pb(II) and Zn(II) ions from industrial sludge and wastewater treatment plants.     

Use of Chemotaxonomy To Study the Influence of Benzalkonium Chloride on Bacterial Populations in Biodegradation Testing

Contradictory results are reported for the behaviour of quaternary ammonium compounds (QACs) in sewage treatment plants (STPs). QACs may sorb onto activated sludge. Only little information is available with respect to effects of QACs against bacteria in STPs. Only 5 to 15 % of bacteria present in sewage sludge can be detected by means of culture dependent microbiological methods. The shift of the bacterial populations due to effects of test compounds have not been studied up to now with culture independent methods. The microbial populations shift was studied in situ using culture independent chemotaxonomy profiling ubiquinones and polyamines. Additionally, toxic effects of QACs against bacteria present in the test vessels of the Zahn‐Wellens test (OECD 302 B) were assessed with a toxicity control in the test. The ubiquinone profiles representing changes in Gram‐negative populations mainly showed that the activated sludge was affected only in test vessels containing benzalkonium chloride. According to chemotaxonomy Acinetobacter or/and some members of Pseudomonas spp. have been selected by benzalkonium chloride after some adaptation period (8 to 12 days).     

The first absolute gravity measurements in Indonesia

For the purposes of the calibration of the superconducting gravimeter (SG) in Bandung and the establishment of the absolute gravity (AG) points, we carried out AG measurements for the first time in Indonesia in November 2002. The measurements in Bandung were conducted between November 15th and 20th by means of a FG5 (#210), and 14,520 effective drops were obtained. The gravity value newly determined at the AG point in Bandung is 977976701.2 μgal (1 μgal = 10⁻⁸ ms⁻²) and the scale factor for the SG is −52.22 μgal/V. We also established another AG point in Yogyakarta near Merapi volcano and carried out AG measurements in Yogyakarta between November 22nd and 26th. The gravity value determined for this station is 978203093.5 μgal.     

Grundlagen für die Dimensionierung der Belüftung bei Belebtschlammanlagen

Summary The generally accepted theory for the calculation of the oxygen consumption caused by the microbes in an aeration basin assumes that the total of oxygen utilizedq _g is the sum of the endogenous respiration of the sludgeq _e plus a quantity for substrate respirationq _s . This theory—though physiologically probably not quite correct—, is very convenient because it allows a causal calculation of the necessary oxygen input into an activated sludge plant. Extensive data on endogenous respiration of activated sludge are presented (Table 1 and 5) and are correlated with sludge load and sludge age (Fig. 4 and 5). The term substrate respiration is discussed and a calculation method, based on the removal of organic C by the mixed liquor, is proposed. In view of the fact that nitrification is an inevitable reaction in activated sludge treatment (its extent being strictly a function of the operation parameters of a plant), oxygen consumption for the oxidation of ammonia has to be included into the term of substrate respiration. The amount of this oxygen fraction has to be predicted from the degree of nitrification to be expected at the desired operation conditions. The following formula for the calculation of the oxygen input into a completely mixed aeration basin is proposed (explanations of symbols see annex): or This same calculation method may be applied stepwise for aeration basins of the tubular reactor type (longitudinal flow basins) considering the concentration decrease of the substrates along the length profile of the basin (the term for endogenous respiration can be assumed constant for the entire aeration time).

---

     

甘肃岷县漳县6.6级地震强震动观测记录与初步分析

2013年7月22日甘肃省定西市岷县漳县交界(东经104.2°,北纬34.5°)发生M6.6地震。甘肃强震动台网在该地区覆盖良好,获得了丰富的主震加速度记录。本文收集整理了此次地震中各强震动台站获得的加速度记录资料并进行了基本处理;经统计分析绘出了峰值加速度分布图。     

场地条件对地面加速度峰值离散性的影响研究

本文在研究了数百个工程场地钻孔资料的基础上,选取和构造了209个有代表性的典型场地剖面,利用目前工程上广泛应用的一维等效线性化波动方法,进行了6种输入强度下(30gal、50gal、100gal、150gal、200gal、300gal)的场地土层地震反应分析.在计算时对每种工况均采用9条互不相关的基岩加速度时程作为输入地震波,同时用均方差来定量评估所得到的地面加速度峰值的离散性,发现计算结果离散性很大,其最大均方差为0.206,最小均方差为0.138,且离散性随基岩地震动输入强度的增大而变大,随场地类别的变差也变大.     

Die Zählung von Protozoen und kleinen Metazoen im Belebtschlamm

Summary: A method for the estimation of the abundance of protozoa and small metazoa in activated sludge is described. 5 × 10 μl of activated sludge are counted in vivo microscopically using a Thoma-Counting-Chamber and a magnification of 100: 1. The efficiency of this counting method was tested by “recovery” experiments. 46–100% of the ciliates (mean 85 %, n = 165 countings) were recovered. A positive correlation between body size and percentage of recovery could be found. Preliminary experiments showed that the method is suitable for nematodes (recovery 95 %, n = 10), rotators (recovery 84 %, n = 10) and testate amoebae (recovery 78 %, n = 10), too. The described method is independent of the sludge-structure, is easy to handle and is an acceptable compromise between time spent and necessary degree of accuracy.     

Waste Activated Sludge Disintegration in an Ultrasonic Batch Reactor

The production of excess sludge is one of the most serious challenges in biological wastewater treatment. In the present work, disintegration is added as a new additional unit operation in a wastewater treatment plant, and the main objective is to reduce the amount of excess sludge. The use of high power ultrasound can effectively disintegrate the bacterial cells, and thereby, enhance the subsequent biodegradation during digestion. In the study, attempts are made to determine the disintegration capacity of waste activated sludge that has different total solids (TS) concentrations with low ultrasound frequency (20 kHz) and a fixed amplitude value (50%). The results show that in terms of soluble chemical oxygen demand (SCOD) release, sludge disintegration was primarily governed by ultrasonic density (W mL^–1), whereas specific energy input appears to be more critical for protein release. A SCOD release of about 329 mg SCOD gTS^–1 was obtained at a TS content of 2% and specific energy input of 5 kWs gTS^–1. The SCOD release decreased to 248.5 and 124.2 mgSCOD gTS^–1 at TS contents of 4 and 6%, respectively. The highest protein release of 80.7 mg gTS^–1 was obtained at a TS content of 2% and a specific energy input of 10 kWs g^–1. The sludge disintegration efficiency declined significantly at higher TS content.