bluuebunny/crossref_metadata_2025_split huggingface dataset:
Particle size analysis and sedimentation properties of activated sludge flocs
Authors: Hilligardt Dieter , Hoffmann Erhard 
Published: May 2018

Activated sludge is one of the best investigated and understood suspensions. But up to now we still lack the factors influencing the sedimentation velocities concerning the main sludge characteristics/properties to describe the settleability of different sludges. Different in terms of SVI, organic loading, sludge retention time, composition, content of polymers, iron or aluminium, density, porosity and particle size distribution. But for the design of clarifiers most of these parameters are disregarded, of none importance or neglectable. With the help of PSD and particle shape analysis we can improve our knowledge of the settleability of activated sludge flocs. The measurements, done with the CIS show the influence of the differential sedimentation in comparison to the effluent of the secondary clarifiers under different conditions.
Calculating the sedimentation velocities, the behaviour of activated and precipitated sludge could be explained and conclusions can be drawn to optimize the solid flux in secondary clarifiers.
Soil clogging in vertical flow reed beds – mechanisms, parameters, consequences and.......solutions?
Authors: Platzer Christoph , Mauch Klaus 
Published: May 2018

The purification efficiency of vertical flow reed beds (VFB) is dependent on a very efficient soil aeration. In most systems this is achieved by intermittent pulse loading at the surface providing an oxygenation by mass flow and diffusion. These oxygen transportation mechanisms only function as long as the upper layers of the bed have a high drainage capacity. Purification efficiency drops significantly when constant ponding occurs.
A review of the literature on clogging in sand filters is given. In our evaluations the following observations are made. Clogging occurs only in the upper 0-15 cm of the bed. Clogging is dependent on the height of organic mass loading. The content of volatile solids in the upper layers could not be proven as a significant parameter influencing clogging. The infiltration rate can be restored by giving the beds a recovery period of several weeks. The required length of rest is dependent on weather conditions, winter is the most critical time.
The design and performance of a vertical flow reed bed for the treatment of high ammonia, low suspended solids organic effluents
Authors: Morris Michael , Herbert Robert 
Published: May 2018

A design approach for vertical flow constructed wetlands based on selection of not only bed size, but also substrate characteristics, configuration, plant species/variety and management is piloted in a trial system to treat sugar beet processing wastes. In the beet processing season these wastes are hot, low in suspended solids and relatively high in ammoniacal nitrogen.
The pilot system consists of a small, coarse substrate first stage followed by a larger, fine substrate second stage. Results in the beet processing season show 87.3% COD removal, 87.7% TSS removal and a 79.5% reduction in ammoniacal nitrogen. Treating larger volumes of cooler stored wastes out of season, the mean removal efficiencies were 73.9% for COD, 88.0% for TSS and 93.4% for ammoniacal nitrogen.
TSS removal m−2 was found to be independent of influent concentration and temperature, whilst COD removal m−2 was found to be independent of temperature, but not influent concentration. Removal of ammoniacal nitrogen appeared to be dependent upon influent concentration and, in particular, upon temperature. Infiltration rates were shown to be negatively correlated to length of dosing cycle. Simple models of substrate permeability based on substrate particle size distribution are seen to be inadequate for describing infiltration rates in vertical downflow systems, even those treating low strength wastes.
Application of derived probability and dynamic programming techniques to planning regional stormwater management systems
Authors: Papa Fabian , Adams Barry J. 
Published: May 2018

There exists a need on the part of land developers or municipalities responsible for stormwater servicing master planning to reduce the costs associated with the initial construction of stormwater facilities as well as with their operation and maintenance. Common integral components of stormwater control systems include stormwater management ponds for water quality control. These ponds may occupy valuable urban land and, hence, it is desirable to minimize the land coverage of these facilities while simultaneously satisfying water quality control objectives. The employment of optimization techniques in the planning and design process can thus play an important role by reducing the costs associated with the implementation of such facilities.
This paper presents an optimization methodology for single catchments using a single stormwater quality control pond. This methodology is then further developed for a multiple parallel catchment (each with a single pond upstream of its outlet) optimization procedure employing principles of dynamic programming. The principal constraint of the problem formulation is to meet a specified pollution control level at the outfall to a receiving water body. The optimization technique employs analytical probabilistic models for stormwater management planning and analysis which are in a mathematically closed form and thus easily integrated into an optimization framework. The costs explicitly considered are land-associated costs and construction costs. Operation and maintenance costs can be incorporated into the framework if desired.
Sustainable water and waste management in urban areas
Authors: Otterpohl Ralf , Grottker Matthias , Lange Jörg 
Published: May 2018

Sewerage system and centralised aerobic wastewater treatment plants (WTP) should not be considered as the only possible solution for sanitation. Systems with source control can avoid many problems of the end-of-pipe technology by respecting different qualities of wastewater and by treating them appropriately for reuse.
Different qualities of waste and wastewater in human settlements and appropriate treatment technologies can be: 1. low diluted faeces with/without urine and bio waste (composter or anaerobic digester), 2. grey ·water/aerobic biofilm plant, 3. storm water (usage and infiltration) and 4. non-biodegradable waste (reuse as raw material). In order to perform resource management, the material originating from agriculture should be returned to the soil as fertiliser. Of similar importance is the organic material. This helps maintaining or building up humus and creates a sink for carbon when the C-content in the soil is increased. Energy will be saved, too: energy-intensive aerobic treatment with nitrification is obsolete as well as the production of the respective amount of replaced artificial fertiliser. A pilot project for a new settlement for about 300 inhabitants in Lübeck, Germany, shall demonstrate the feasibility of a new integrated system with vacuum toilets and pipes for the collection of black water. This will be mixed with shredded bio waste and fed to a semicentralised biogas plant that produces liquid fertiliser without dewatering. Grey water will be treated in decentralised biofilm systems. Storm water is collected, retained and infiltrated in a trench system. This way the expensive centralised sewerage system can be avoided for this settlement.
Verification of anoxic phosphate uptake as the main biochemical mechanism of the “dephanox” process
Authors: Sorm R. , Wanner J. , Saltarelli R. , Bortone G. , Tilche A. 
Published: May 2018

The phenomenon of anoxic phosphate uptake with simultaneous denitrification was studied. For this purpose kinetic batch tests have been carried out by using the activated sludge samples from three modifications of nutrient removal activated sludge systems: two based on an anaerobic-anoxic-oxic (A2/O) system and a third on an anaerobic-oxic (A/O) system.
The results showed significant differences in anoxic phosphate uptake rate between activated sludge which was alternatively exposed to anoxic conditions and activated sludge from the A/O arrangement. These differences were also accompanied by different denitrification rates. Simultaneously with batch experiments the microscopic observation of activated sludge samples was carried out. Neisser and Gram stained samples showed clear differences in shape, size and distribution of polyphosphate accumulating bacteria between A2/O and A/O Processes. Moreover, experiments performed using genetic probes confirmed the differences in microbiological composition of activated sludge samples from different nutrient removal system arrangements.
Anaerobic treatment of inuline effluent in an internal circulation reactor
Authors: Habets L. H. A. , Engelaar A. J. H. H. , Groeneveld N. 
Published: May 2018

Sensus Operations C.V. is a 100 percent subsidiary of the Dutch Suiker Unie group (Cosun). At the site in Roosendaal it operates an inuline and fructose production line, using chicory beet as raw material. Inuline is a product which is gaining more and more popularity as a structural improver in food, as a low calory replacement in ice-cream and chocolate bars and as moisturizer to improve the spreadability of cleaning products. It consists of a polyfructose fibre which is hardly degraded in the human body.
The cleaning and chipping process of the chicory beet is similar to the sugar beet preparation process and so is the effluent. The production process itself is different and the effluent released, also contains the effluent from a demineralisation plant, which results in an additional high COD and salt loaded effluent. During the first two years of inuline production the “heavy water” (high COD, salty effluent) was simply added to one of the existing UASB reactors, because the inuline factory was running at a very low capacity. However since 1995 the production could be increased drastically to 1500 tpd so that an extra anaerobic treatment unit had to be installed. The third would require enough capacity to convert 30 tons of COD per day (COD load 37.5-40 tpd). However, the investment was quite high and the reactor volume would be of such a size that it would be more difficult to operate, considering the sludge weight and the important ground surface. At the moment the size of the reactor was known, the idea was born to consider the installation of an Internal Circulation (IC) reactor. This reactor was 25% lower in investment cost and space occupation was only 55 m2 instead of 450 m2. This paper reveals the performance of the IC reactor during the first campaign in 1995.
Resistance of EDTA and DTPA to aerobic biodegradation
Authors: Hinck M. L. , Ferguson J. , Puhaakka J. 
Published: May 2018

Ethylenediamine tetraacetic acid (EDTA) and diethylenetriamine pentaacetic acid (DTPA) are synthetic chelating agents that form stable complexes with most metals and are used in a variety of industrial applications. They are increasingly used with peroxide and ozone bleaching of wood pulp to sequester iron and manganese. These chelates have been widely reported to either resist degradation or undergo slow biodegradation. EDTA and DTPA have few known environmental impacts in receiving waters.
A study was conducted to assess the biodegradability of EDTA and DTPA and to determine if these compounds could be transformed in conventional effluent treatment processes. Four dissimilar inocula were used in batch and continuous aerobic tests using a variety of enrichment techniques. Selection pressure was applied to bacterial populations by providing EDTA and DTPA as sole carbon sources. Additionally, experiments were conducted using degraders of chemically similar compounds nitrilotriacetic acid and triethanolamine. In all experiments, the results showed that neither EDTA or DTPA are biodegraded under aerobic conditions.
In line biological water regeneration in a zero discharge recycle paper mill
Authors: Habets Leo H. A. , Knelissen Heins J. 
Published: May 2018

The recycled paper group of KNP-BT operates in total 12 paper and board mills in Western Europe. All together the output of recycled product is 1.5 million tpy, of which approx. 50% is testliner and corrugated medium. The company has been a pioneer in process water closure for more than 20 years and several of its mills were already operating totally effluent free, long before the term “zero effluent” was invented.
Some advantages of this way of operation are energy conservation and no charges for effluent discharge. Disadvantages are amongst others, accumulation of organic compounds, increased salt content, water hardness and volatile fatty acid build up.
One of the fluting and testliner mills in the group is Zülpich Papier, which is currently going through an extension phase from 170.000 tpy to 340.000 tpy. This particular mill has been operated under complete effluent free circumstances almost 20 years. However, even though the new machine is to be put into operation in October 1996, a biological process water regeneration plant has been put on stream already in September 1995 in order to collect experience with the internal treatment and to have everything running smoothly by the time the new machine is started.
The in line treatment consists of an anaerobic and an aerobic stage. During the first stage the dissolved organic components like carbohydrates and volatile fatty acids are converted into methane gas. At the same time, sulphate reducing bacteria convert sulphate into hydrogen sulphide, which is stripped out by the biogas. During the subsequent aerobic stage, residual organic components are oxidized into carbonate, which precipitates with calcium ions into the aerobic sludge and accumulates as calcium carbonate. These are a few examples of what is being achieved. Due to several favourable reactions in the biological stage, the process water quality has improved drastically for the following criteria:
Odour, corrosion properties, salt content (conductivity), hardness, viscosity, COD-level and pH. Also components like stickies, waxes and colloidal material are presumably being degraded during the biological regeneration process.
In the paper a description is given of the plant, as well as an overview of the main improvements of the process water quality during the first four months of in line biological treatment.
An assessment of the quality and treatment of detergent wastewater
Authors: Papadopoulos A. , Savvides C. , Loizidis M. , Haralambous K. J. , Loizidou M. 
Published: May 2018

Removal efficiency of organic load from a detergent wastewater by a bench scale physical-chemical treatment is reported. The results of the wastewater characterisation showed that the concentrations of the organic matter were very high, expressed as COD, ranging from 2400-26,400 mg/l, while the biodegradable portion was very low, since the BOD/COD ratio was low. These values indicate that organic compounds are not easily subjected to biological treatment. In addition, methylene blue active substances appeared in high concentrations as well as sulphates and ammonia.
The experiments for the treatment of the wastewater were performed using various chemicals such as lime, alum and polyelectrolyte. The use of lime gave a 26% average COD removal, while by using alum a slightly lower removal was achieved, 23%. The use of lime (pH=9-10) in combination with alum led to a 41% COD reduction. Similar removal was achieved by using alum (pH=5-6) in combination with lime, 43%. Finally, the addition of polyelectrolyte in the systems of lime and alum did not improve total removal of organic matter giving reductions of 46% and 48%, respectively.
Methanogenesis in sediments from deep lakes at different temperatures (2–70°C)
Authors: Nozhevnikova Alla N. , Holliger C. , Ammann A. , Zehnder A. J. B. 
Published: May 2018

Methanogenic degradation of organic matter occurs in a wide temperature range from psychrophilic to extreme thermophilic conditions. Mesophilic and thermophilic methanogenesis is relatively well investigated, but little is known about low temperature methanogenesis and psychrophilic methanogenic communities. The aim of the present work was to study methanogenesis in a wide range of temperatures with samples from sediments of deep lakes. These sediments may be considered deposits of different types of microorganisms, which are constantly exposed to low temperatures. The main question was how psychrophilic methanogenic microbial communities compare to mesophilic and thermophilic ones.
Methanogenesis in a temperature range of 2–70°C was investigated using sediment samples from Baldegger lake (65 m) and Soppen lake (25 m), Switzerland. Methane production from organic matter of sediments occurred at all temperatures tested. An exponential dependence of methane production rate was found between 2 and 30°C. Methanogenesis occurred even at 70°C. At the same time stable methane production from organic matter of sediments was observed at temperatures below 10°C. Methanogenic microbial communities were enriched at different temperatures. The communities enriched at 4–8°C had the highest activity at low temperatures indicating that a specific psychrophilic community exists. Addition of substrates such as cellulose, volatile fatty acids (butyrate, propionate, acetate), methanol and H2/CO2 stimulated methane production at all temperatures. H2/CO2 as well as methanol were directly converted to methane under thermophilic conditions. At low temperatures these substrates were converted to methane by a two-step process. First acetate was formed, followed by methane production from acetate. When acetate concentrations were high, acetoclastic methanogenesis was inhibited at low temperatures. This reaction appears to be one of the “bottle neck” in psychrophilic methanogenesis.
Kinetic data and new enzymatic activities of Methanosarcina barkeri grown on methanol as the sole carbon source
Authors: Daußmann Thomas , Aivasidis Alexander , Wandrey Christian 
Published: May 2018

The strictly anaerobic methanogen Methanosarcina barkeri strain Fusaro (DSM 804) was fermented on a 3-liter scale in a CSTR (continuous stirred tank reactor) to obtain almost 10 g biomass dry weight per day. The generation time of the microorganism with methanol as the sole carbon source was 6.0 h, the maximal growth rate 0.115 h−1 correspondingly.
In cell-free extracts from the fermented organism active hydrogenases were found. They reduced methyl viologen (MV⊕⊕), an artificial electron acceptor, molecular hydrogen being the substrate. This reaction was used to get electrochemical energy in a biochemical fuel cell. The maximum output of this fuel cell was 2.6 mW.
Furthermore, cell-free extracts from M. barkeri showed alcohol dehydrogenase activity under aerobic conditions when N,N′-dimethyl-4-nitrosoaniline (NDMA) was used as an artificial electron acceptor. The NDMA-dependent alcohol dehydrogenase (NDMA-ADH) was purified to homogeneity by column chromatography. It is a homodimeric enzyme consisting of subunits of 45 kDa, the native molecular mass is about 87 kDa. The enzyme is independent of free coenzyme such as NAD, NADP, FMN, FAD and F420, but it possesses a tightly but noncovalently bound NADP(H) cofactor.
The purified enzyme exhibited activity only with primary alcohols including aromatic alcohols, but methanol was not accepted. It also catalyzed the stoichiometric dismutation of aldehydes, especially long-chain aldehydes, to form a half mol of each of the corresponding alcohol and acid without addition of an electron carrier. NDMA-ADH from M. barkeri is a novel type of nicotinoprotein in methanogenic bacteria.
Innovative technology for the improvement of the anaerobic methane fermentation
Authors: Dohányos Michal , Zábranská Jana , Jenícek Pavel 
Published: May 2018

The intensification method of anaerobic methane fermentation of sludges, based on the stimulation activity of cell lysate, was studied. The effect of lysate is caused by the still remaining activity of released enzymes and by the stimulating properties of other compounds that are present inside the cells. The anaerobic cell lysate was prepared by a thermal treatment of anaerobic sludge and the aerobic cell lysate by a partial mechanical destruction of cells of the excess activated sludge by a special adapted thickening centrifuge.
The use of cell lysate as a stimulating agent was examined in the laboratory experiments of anaerobic degradation of simple organic compounds (glucose, acetate, formate and propionate) and of complex substrates as municipal raw sludge, excess activated sludge and some pharmaceutical organic wastes. The results show a significant improvement of the removal rates of substrates and the enhancement of methane production in all cases of lysate addition. In the fermentation of raw sludges and pharmaceutical wastes with anaerobic lysate, the increment of the methane yield ranges from 38.2–61.8% and 20.2–36.7% respectively. The aerobic lysate increased the methane yield of excess activated sludge and of its mixture with primary sludge at the range of 17.1–86.4% and 24% respectively.
Temperature-phased anaerobic digestion of wastewater sludges
Authors: Han Yue , Sung Shihwu , Dague Richard R. 
Published: May 2018

The temperature-phased anaerobic bioreactor (TPAB) has been under study by Dague and co-workers at Iowa State University. The temperature-phased approach involves a two-stage reactor system with the first stage operated at a thermophilic temperature (commonly 55°C) and the second stage operated at a mesophilic temperature (commonly 35°C). The purpose of laboratory study was to compare the performance of the temperature-phased system with the conventional single-stage mesophilic system for treating mixtures of primary and waste activated sludge. Of particular interest in the research was a comparison of the two systems from the standpoint of coliform reduction, volatile solids (VS) destruction, and biogas production.
The temperature-phased system achieved complete destruction of total and fecal coliforms over a range of SRTs from 11 to 28 days. The concentration of fecal coliforms in the effluent from the temperature-phased system never exceeded 1000 MPN/g total solids (TS), which can meet the U.S. Code of Federal Regulations, Title 40 (40 CFR), Part 503 coliform requirements for Class A sludge. At the optimal SRTs ranging from 11 to 17 days, the capacity of VS removal of temperature-phased system was more than double that of the conventional single-stage system. The foaming problem associated with the digestion of waste activated sludge was eliminated.
UASB-reactor in the fruit juice industry
Authors: Austermann-Haun Ute , Seyfried Carl Franz , Rosenwinkel Karl-Heinz 
Published: May 2018

This paper presents experiences with a full scale UASB-reactor in a fruit juice factory. The focus is on demonstrating that a UASB-reactor is as suitable for campaign industries running only 2 months a year with higher concentrated wastewater as well as for the time outside the campaign when the wastewater concentrations are very low (average COD 1000 mg/l). A number of operating results and recommendations are given, resulting from the experiences in order to show solutions for handling these very different situations. Examples of recommendations are: discontinuous feeding 8 hours a day outside the campaign, removal of pellet sludge at the end of the campaign. These frame conditions provided a COD removal efficiency in the UASB-reactor consistently above 80% throughout the year. Furthermore, it is shown that the anaerobic pre-treatment of industrial wastewater is the cheapest way in regard to the running expenses.
Another point of research was the co-fermentation of the kieselguhre-sludge-mixture. Although only 10% of the load was based on this substrate at a volumetric loading rate of 3 kg COD/(m3 · d), there was a quick drop in pH to a level of 3.5 and the pellet structure of the biomass got lost.