bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimisation of Hamburg's wastewater treatment plants - three years of experience with the new concept
Authors: Ladiges G. , Bertram N.-P.
Published: May 2018

In the end of the year 1999 a new concept for Hamburg's wastewater treatment plants was commissioned to cope with the additional load of 250,000 PE which has been connected to the existing plant serving 1.85 million population equivalents. The new concept consists of an additional tank for the storage of sludge liquor to avoid peak nitrogen concentrations in the effluent of the plant. This solution has been developed within a study assessing a wide range of concepts with costs between initial €100 million and the final construction costs of €1 million. Here the dynamic simulation showed to be a very efficient planning tool. Within the first three years of operation the chosen solution showed to be able to fulfil the requirements. In 2002 the concept has been improved by a few more measures, mainly the equipment of one of the storage tanks as a SAT tank for further cost effective nitrogen removal. For a further improvement of the treatment capacity additional measures are planned to be carried out within the next years.
Combined quantity management and biological treatment of sludge liquor at Hamburg's wastewater treatment plants - first experience in operation with the Store and Treat process
Authors: Laurich F.
Published: May 2018

Store and Treat (SAT) is a new concept for the management of ammonium-rich process waste aters at wastewater treatment plants. It combines the advantages of quantity management and separate biological treatment, whereby both operations are carried out in the same tank. Now the first full-scale application of that method was realized in Hamburg. As first experience shows the process can help to increase nitrogen removal and to reduce energy consumption.
Sewage-treatment under substantial load variations in winter tourism areas – a full case study
Authors: Winkler S. , Natsché N. , Gamperer T. , Dum M.
Published: May 2018

The sewage-load variations in winter tourism areas are characterized by sudden increases - in the ange of a factor two to three - within only a few days at the start and the end of the tourist season, especially at Christmas. The sudden load increases occur during periods of low wastewater temperatures, which is an additional demanding factor with respect to nitrogen removal.

A full case study was carried out at WWTP Saalfelden, which is located near one of Austria's largest skiing resorts. The plant is designed for 80,000 PE and built according to the HYBRID®-concept, which is a special two stage activated sludge process for extensive nutrient removal.
North American performance experience with anoxic and anaerobic selectors for activated sludge bulking control
Authors: Parker D. , Appleton R. , Bratby J. , Melcer H.
Published: May 2018

Obtaining reliably high compaction characteristics and low SVI values has enormous economic consequences on activated sludge plant design and operation. Now that use of selectors has become more common for achieving low SVI values, the assessment of the full-scale performance characteristics of activated sludge plants incorporating selectors has high value for the design and operation of future plants. Treatment plant effluent quality is seldom analyzed solely on an average basis and the impact peak events have on effluent quality must be considered in design and operation. Descriptive statistics should also be used to assess selector performance, so that the influence of infrequently occurring values on plant design and operation can be assessed. The performance of 21 activated sludge plants incorporating selectors was evaluated. All the selector plants for which post installation data were available showed that the operating SVI values were significantly improved. One plant studied in detail showed that final effluent quality was significantly better after the selector installation. As a group, activated sludge plants with anaerobic selectors outperform those with anoxic selectors. Dissolved oxygen control is just as important in activated sludge plants with selectors as in conventional activated sludge plants.
A new side stream process for easily degradable industrial waste waters to avoid sludge bulking
Authors: Wandl G. , Matsché N. , Bayer H.
Published: May 2018

A new treatment scheme for the treatment of easily biodegradable industrial waste waters has been developed. The side stream treatment of dairy waste water with the excess sludge from the domestic treatment line of the regional treatment plant Bad Vöslau has been operated successfully for a period of three years during which the industrial load stemming from the dairy increased from 800 kg COD/d to 2,500 kg COD/d with peak loads up to 5,000 kg/d. Despite of the increased load to the treatment plant the total aeration tank volume had not been increased. This treatment is performed in an existing aeration tank of the WWTP (V = 1,800 m3) which is now used as contact tank for the combined aeration of dairy waste water and excess sludge from the domestic treatment line (volume aeration tank = 15,000 m3). In this tank the easily degradable substrate from the industrial waste is mainly adsorbed to the biological sludge and after a mechanical dewatering transferred to the anaerobic digester where it yields in an increased gas production. The filtrate of the dewatering process is completely free from biodegradable material and can without danger of bulking be fed to the aeration tank of the domestic treatment line.

The new process has proven to be extremely flexible since already now daily peak loads exceeding the design load by more then 60% could be treated in the plant without any problems. Compared to other alternatives for the dairy waste water treatment that were investigated during this study, the new side stream process is very advantageous. No other pre-treatment process for industrial waste water could have been operated under comparable loading conditions without severe operating problems.
The effect of public or private structures in wastewater treatment on the conditions for the design, construction and operation of wastewater treatment plants
Authors: Grünebaum T. , Bode H.
Published: May 2018

Organised in public or private structures, wastewater services have to cope with different framework conditions as regards planning, construction, financing and operation. This leads quite often to different modes of management. In recent years there has been a push for privatisation on the water sector in general, the reasons for which are manifold, ranging from access to external know-how and capital to synergistic effects through integration of wastewater treatment into other tasks of similar or equal nature.

Discussed are various models of public/private partnership (PPP) in wastewater treatment, encompassing for example the delegation of partial tasks or even the proportional or entire transfer of ownership of treatment facilities to private third parties. Decisive for high performance and efficiency is not the legal or organisational form, but rather the clear and unmistakable definition of tasks which are to be assigned to the different parties, customers and all other partners involved, as well as of clear-cut interfaces. On account of the (of course legitimate) profit-oriented perspective of the private sector, some decisionmaking processes in relation to project implementation (design and construction) and to operational aspects will differ from those typically found on the public sector. This does apply to decisions on investments, financing and on technical solutions too. On the other hand, core competencies in wastewater treatment should not be outsourced, but remain the public bodies’ responsibility, even with ‘far-reaching’ privatisation models. Such core competencies are all efforts geared to sustainable wastewater treatment as lifesupporting provision for the future or as contribution to the protection of health and the environment and to the development of infrastructure. Major areas of wastewater treatment and other related tasks are reviewed. The paper concludes with a list of questions on the issue of outsourcing.
In-situ characterization of microbial community in an A/O submerged membrane bioreactor with nitrogen removal
Authors: Sofia A. , Liu W.-T. , Ong S.L. , Ng W.J.
Published: May 2018

The bacterial community involved in removing nitrogen from sewage and their preferred DO environment within an anoxic/oxic membrane bioreactor (A/O MBR) was investigated. A continuously operated laboratory-scale A/O MBR was maintained for 360 d. At a sludge age of 150 d and a C/N ratio of 3.5, the system was capable of removing 88% of the influent nitrogen from raw wastewater through typical nitrogen removal transformations (i.e. aerobic ammonia oxidation and anoxic nitrate reduction). Characterization of the A/O MBR bacterial community was carried out using fluorescence in situ hybridization (FISH) techniques. FISH results further showed that Nitrosospira spp. and Nitrospira spp. were the predominant groups of ammonia and nitrite oxidizing group, respectively. They constituted up to 11% and 6% of eubacteria at DO below 0.05 mg/l (low DO), respectively, and about 14% and 9% of eubacteria at DO between 2–5 mg/l (sufficient DO), respectively, indicating preference of nitrifiers for a higher DO environment. Generally low counts of the genus Paracoccus were detected while negative results were observed for Paracoccus denitrificans, Alcaligenes spp, and Pseudomonas stutzeri under the low and sufficient DO environments. The overall results indicate that Nitrosospira spp., Nitrospira spp. and members of Paracoccus spp. can be metabolically functional in nitrogen removal in the laboratory-scale A/O MBR system.
Sludge thickening performance of mesh filtration process
Authors: Park M.-S. , Kiso Y. , Jung Y.-J. , Simase M. , Wang W.H. , Kitao T. , Min K.-S.
Published: May 2018

Small-scale wastewater treatment facilities play an important role in improving the aquatic environment in many countries. Although sludge treatment is essential for overall wastewater treatment, it is difficult for small-scale facilities to use mechanical equipment or other facilities. As the first step of the sludge treatment, it is important to develop a convenient sludge thickening process for small-scale facilities. In this work, we examined the sludge thickening performance of a mesh filtration system: the mesh opening sizes of 100-500 μm, and the sludge (3,000-9,000 mg-SS/L) was obtained from a domestic wastewater treatment facility. The filtration was carried out only under the hydraulic pressure between the water level and the effluent port connected to the mesh filter module. The sludge reduction rates were in the range of 85-95% for 6-7 h; the initial filtration rate was very high, but the rate decreased with a decrease in hydraulic pressure due to the reduction of the water level in the vessel. In addition, the effluents (passed through the mesh) contained very low SS and could be directly discharged into the environment.
Case study: a decade of changes in a small environmental engineering graduate program
Authors: Leung S.W.
Published: May 2018

For a small graduate program in environmental engineering in a rural state in the US, it is important for the program curriculum to stay in the mainstream. While resident student enrollment is approaching a steady level, international student enrollment increases steadily, this is due in part to the out-of-state tuition waiver provided to the students. Part-time students are a significant part of the program, these students have special needs that are different from traditional full-time students that must be taken into consideration in program planning. A small program provides an attentive atmosphere for students’ learning, but it also has problems that a larger program would not encounter, such as competitiveness, personal conflicts, program identity, etc. Despite success in the past, the program is likely to merge with other related programs in the university during times of budget restrictions.
European higher education space: where do we go from here?
Authors: Iza J. , García Encina P.
Published: May 2018

The Declaration of Bologna and subsequent documents have drastically changed the European university panorama and the future role of universities as providers of continuous education for a lifelong learning. There will be a convergence not only in academic titles, but also in the way we see university education. The previous EEE symposium gave some clues on the approaches taken by different European countries: organization of EE studies, integration of graduates into the market, and interaction with professional bodies. Bologna's outcomes were sold in Spain as a change into an American (USA) model, which, as any other model, has advantages and drawbacks. This paper deals with an open reflection on the future of university studies in Europe.
Nitrate removal with low N2O emission by application of sulfur denitrification in actual agricultural field
Authors: Hasegawa K. , Shimizu K. , Hanaki K.
Published: May 2018

Sulfur denitrification was applied to the agricultural field and the characteristics of the treatment were evaluated from the viewpoints of nitrate removal efficiency and nitrous oxide (N2O) emission. Two actual sites where sulfur denitrification was performed were surveyed. One is a valley bottom field, where groundwater contaminated with nitrate is coming up as spring water. The nitrate concentration in influent was about 45 mgN/L. The other was wastewater from a plastic greenhouse. The nitrate concentration in inflow water was about 200 mgN/L. Nitrate was almost removed by the containers packed with sulfur (S0)- CaCO3 blocks in both sites. Increase of sulfate indicated that nitrate was removed by sulfur denitrification. This was also estimated stoichiometrically from the relationships between the removed nitrate and produced sulfate. The N2O was supersaturated in water at most sampling points and the highest concentration of dissolved N2O reached 900 μgN/L in Saitama in March. It seemed that insufficient nitrate removal caused accumulation of intermediates during denitrification, such as nitrite and N2O, in this month. However, the emission ratio of N2O to the removed nitrate during these processes was kept low, ranging from 0.01 to 0.19%, at both two sites throughout all surveys.
Enhanced remediation of carbon tetrachloride Fe(II)-Fe(III) systems in the presence of copper ions
Authors: Maithreepala R.A. , Doong R.-A.
Published: May 2018

The effect of Cu(II) ion on the dechlorination of carbon tetrachloride (CT) by Fe(II) associated with various iron oxides was investigated. Iron oxides including goethite, hematite, ferrihydrite and magnetite were selected as the model compounds. CT was dechlorinated to chloroform (CF) by 3 mM Fe(II) in iron oxide suspensions at pH 7.2. The dechlorination followed pseudo first-order kinetics and the pseudo firstorder rate constants (kobs) were 0.048 h−1, 0.0836 h−1, 0.0609 h−1 and 0.0144 h-1 in goethite-, hematite-, ferrihydrite- and magnetite-amended systems, respectively. Addition of Cu(II) into systems increased the kobs for CT dechlorination significantly. A 3- to 120-fold increase in kobs relative to the systems without Cu(II) was observed when 0.5 mM Cu(II) was added to the Fe(II)-Fe(III) suspensions. The pH of the system is an important factor controlling the dechlorination rate of CT. The increase in concentrations of Fe(II) and iron oxides also enhanced the dechlorination efficiency and rate of CT. Moreover, a linear relationship between the kobs and Cu(II) concentration ranging between 0 and 0.4 mM was observed. Results obtained demonstrate the feasibility of using surface-bound iron species with Cu(II) for the detoxification of chlorinated solvents in the contaminated aquifers.
Pretreatment of silk-dyeing industrial wastewater by UASB reactor
Authors: Karnchanawong S. , Sawangpanyangkura T.
Published: May 2018

The objective of this study was to investigate the performance of the upflow anaerobic sludge blanket (UASB) reactor as the pretreatment system for silk-dyeing wastewater. Two laboratory-scale UASB reactors, with working volume of 15.59 l, were used during May 1998 to June 1999. The actual wastewater was diluted to reduce ammonium ion toxicity on anaerobic bacteria. The experiments were conducted at the organic loading rates (OLRs) of 0.52, 1.01, 1.04, 1.54 and 2.56 kgCOD/(m3.d), treating only wastewater generated from the acid-dye process of mixed-species raw silk. It took approximately 41/2 months to reach the steady-state conditions. It was found that the COD removal was in the ranges of 74.1-85.3% , except at OLR 2.56 kgCOD/(m3.d) where efficiency significantly dropped to 55.2%. The apparent color removal was in the similar trend as COD. During the study periods, wastewater input had various color shades while the effluent generally looked pale yellowish. The methane generation rates ranged from 0.18-0.31 m3/kg COD removed, with methane composition 81.0-88.1% in biogas. The average granule size in the sludge bed had slowly increased to 0.73 mm in the last experiment. It can be concluded that the UASB reactor is suitable as a pretreatment system for silk-dyeing wastewater. An OLR of 1 kgCOD/(m3.d) and an influent concentration diluted to 2,600 mgCOD/l are suggested while COD and apparent color removal efficiency of 80% and 70%, respectively, can be expected.
The olfactory experience: constants and cultural variables
Authors: Candau J.
Published: May 2018

Odor and olfaction anthropology explores four lines of research which, in many cases, may overlap: the variability of the olfactory perception, olfactory skills and know-how, odor use, and odor representations. My proposal here is to deal with the first one, trying to answer the following question: is olfactory perception a phenomenon resulting solely from the biological organization of the human being, in such a way that it does not know other variations than the ones due to nature? Or, on the contrary, can we show different kinds of olfaction culturally determined or, at least, environmental influences resulting in significant perceptual differences among groups, societies, cultures, etc.? In the first part of the text, I will deal with the invariants (or universals). In the second, I will insist on the cultural types of olfaction. In the third and last part, I will advance the following proposal: beyond the discussion on the roles that nature and culture play in human olfaction, we can sustain that naturally and culturally, there is a way of smelling characteristic of our species. Finally, I will conclude with two examples of the symbolic treatment characteristic of the olfactory human experience.
Effect of the application of acid treated biosolids on marigold (Tagetes erecta) development
Authors: Diaz-Avelar J. , Barrios J.A. , Jimenez B.
Published: May 2018

The use of biosolids for land restoration and crop production is a potential solution to improve food production worldwide. However, the microbial content usually restricts its application in crops that are consumed uncooked. An alternative practice is their use in floriculture. In this study, the effects of acid treated sludge on the development of marigold (Tagetes erecta) plants were evaluated under green house conditions. Biosolids were applied at the agronomic rate (AR) based on nitrogen requirements of the marigold. In addition, higher rates (10 and 20×AR) were applied to study their effect on the plants. Biosolids were mixed with tepetate (hard volcanic indurate layers). Due to its origin, tepetate lacks nutrients and organic matter to adequately support plant development. The best treatment for marigold development was 10×AR, as plants reached an average height of 107 cm, with a growing speed of 1.01 cm/d, which is 20 times more than the control. Plants that received no biosolids produced 0.25 buds and 0.5 flowers per plant. In contrast, AR and 10×AR showed a production that ranged from 2 to 29 buds/plant and 4 to 15 flowers/plant, respectively. These results indicate the viability of reusing acid treated biosolids to improve marigold development.
Rating method for evaluating distribution-system odors compared with a control
Authors: Dietrich A.M. , Burlingame G.A. , Vest C. , Hopkins P.
Published: May 2018

A new sensory method was developed and tested at a full-scale water treatment plant. The method evaluates changes in aesthetic water quality during transit in the distribution system. A paired comparison format is used to determine if the odor of a distribution-system sample is different from that of a control sample. The control sample represents the “ideal” water, such as treated water leaving the plant. The method can rapidly determine whether or not a problem exists in the distribution system, and, if one does exist, it allows for characterization of the problem. Over a three-month period a 4-member odor panel evaluated 118 distribution samples by this new procedure. Among the 118 samples tested, 39 samples yielded a consensus among the analysts as to the odor characteristics of the sample; 35 were rated “not different from the control” (about 90%), and only 4 were rated “different from control” (about 10%). The 79 samples for which no consensus was generated had only slight rating differences between analysts and for odor intensity. No taste-and-odor problems were reported by consumers during the time period for this study and the method indicated that no major odor problems existed in the distribution system.
Enhanced heavy metal bioleaching efficiencies from anaerobically digested sewage sludge with coinoculation of Acidithiobacillus ferrooxidans ANYL-1 and Blastoschizomyces capitatus Y5
Authors: Wong J.W.C. , Gu X.Y.
Published: May 2018

Prolonged bioleaching period was required to remove heavy metals from anaerobically digested sewage sludge in the presence of low molecular weight organic acids. The purpose of the present study was therefore to enhance metal solubilization efficiencies through introducing organic acid-degrading microorganisms into this artificial bioleaching system. An acetic and propionic acid-degrading yeast Blastoschizomyces capitatus Y5 was successfully isolated from a local Yuen Long sewage sludge and it could achieve optimum growth in synthetic liquid media containing 2,000 mg l-1 acetic acid or 1,000 mg l-1 propionic acid. When it was inoculated simultaneously with Acidithiobacillus ferrooxidans ANYL-1 into anaerobically digested sewage sludge, which contained 648 mg l-1 acetic acid and 731 mg l-1 propionic acid, both acids were completely decomposed within 24 hours. As a result, ferrous iron oxidation was greatly improved, resulting in enhanced metal solubilization. Compared with the 8, 10 and 12 days required for maximum solubilization of Zn, Cu and Cr for the control sludge, the bioleaching period was significantly shortened to 4, 5 and 8 days respectively for sludge receiving co-inoculation.
Energy and nutrient recovery from sewage sludge via pyrolysis
Authors: Bridle T.R. , Pritchard D.
Published: May 2018

Energy recovery and nutrient reuse from sewage sludge has traditionally been achieved via anaerobic digestion/power generation with land application of the biosolids. By contrast, thermal processes such as pyrolysis have typically been used only for energy recovery. One such technology has demonstrated at commercial scale that all of the energy in sludge can be beneficially recovered and reused. No attempt was however made to recover and reuse sludge nutrients. There are many potential benefits of using pyrolysis for both energy and nutrient recovery. Firstly, unlike digestion, the principal energy product is oil, which can readily be stored and used when required, ensuring that energy recovery is maximised. Secondly is that the sludge nutrients are recovered in the pyrolysis char. Laboratory soil incubation studies using char from the Subiaco demonstration plant were conducted over an eight-week period to confirm nutrient availability. Results from this study showed that the phosphorus in the char is plant available although the nitrogen was insoluble. Based on these results it appears that there is potential to use pyrolysis as an effective means to recover and reuse both the energy and the very valuable phosphorus present in sewage sludges.
Understanding odorants associated with compost, biomass facilities, and the land application of biosolids
Authors: Rosenfeld P.E. , Suffet I.H.
Published: May 2018

Odorous water and air can result from compost, biomass facilities and land application of biosolids. Common odorous compounds from these biodegradation systems include alcohols, aldehydes, fatty acids, solvents and various sulfur and nitrogen compounds. Each odorant possesses a unique individual odor signature i.e. odor character or quality, odor threshold concentration and chemical concentration. This paper develops an initial understanding of how the volatile odorous chemicals and their relative concentrations produced are related to the total odor quality from the process by their odor threshold concentrations. The compost process is used as an example. It was estimated, that on day 1 and 7, the primary fatty acids controlling the fermented and rotten odors were butyric acid and valeric acids, individually, unpleasant and rancid odors, respectively, although acetic acid had the highest fatty acid concentration on both days. In the same way, aldehydes and ketones controlled the disappearance of the sweet odor from day 1 to 7.
Sludge as source of energy and revenue
Authors: Onyeche T.I.
Published: May 2018

Sludge is a residue/product from wastewater treatment plants and contains most of the contaminants released during human activities. Some stringent environmental regulations on sludge treatment and disposal exist in many countries. This has resulted in increasing interest in sludge treatment methods that encourage sludge reduction and improvement in biogas production during anaerobic digestion processes. This work demonstrates the first exploitation of valuable energy from homogenised sludge at technical scale with mass reduction. The optimal combination of sludge homogenisation at relatively low pressures using a modified high-pressure homogeniser led to the success of this unique project. Results showed that about 30% more energy could be obtained from thickened and disrupted sludge than from untreated samples. The energy produced was higher than that invested during disruption and digestion processes. About 23% sludge reduction was also observed with no increase in chemical oxygen demand. This new process can produce extra energy for local electrification and heating the digester while the sludge reduction provides economic benefits. Concentration of sludge causes reduction in investment cost on digester as well as reduction in operational time for sludge dewatering.
Recovery of energy from sludge – comparison of the various options
Authors: Rulkens W.H. , Bien J.D.
Published: May 2018

This paper gives a general discussion of existing sludge treatment processes and of innovative treatment options, especially focused on the valuable use of organic carbon compounds as an energy source. Attention is paid both to high and to low temperature processes and to combinations of these processes. Based on an assessment and comparison the most beneficial and sustainable options are identified and a rough indication is given of the possibilities for improvement and future developments.
The effect of water quality and NOM character on the ozonation of MIB and geosmin
Authors: Ho L. , Croué J.-P. , Newcombe G.
Published: May 2018

The ozonation of MIB and geosmin was studied in synthetic waters containing two natural organic material (NOM) fractions and sodium bicarbonate. The ozonation of both compounds was found to be affected by the character of the NOM fractions, with higher apparent rate constants observed in the fraction containing higher UV/visible absorbing properties. As the concentration of bicarbonate was increased, the destruction of both compounds decreased. MIB was found to be more resistant to ozonation than geosmin.
Combining SBR systems for chemical and biological treatment: the destruction of the nerve agent VX
Authors: Irvine R.L. , Haraburda S.S. , Galbis-Reig C.
Published: May 2018

The US Army is pilot testing the neutralization of VX nerve agent stockpiled at Newport, Indiana using caustic hydrolysis in a Sequencing Batch Reactor (SBR). The resulting hydrolysate was tested at the bench-scale for treatment with activated sludge biodegradation in two distinct studies, one in the SBR and another, in the PACT® process. The feed to both biological systems was pretreated to enhance the biodegradability of the hydrolysis products. Both biodegradation studies demonstrated that the hydrolysate could easily meet the Chemical Weapons Convention treaty and US environmental regulations following pretreatment.
Contaminants in sludge: implications for management policies and land application
Authors: Dentel S.K.
Published: May 2018

Policies on sludge (or biosolids) management vary widely, particularly when decisions must be made on what to do with the final product. This paper examines the two principal rationales with which such decisions are made, and through which scientific knowledge is included in the process. These rationales are risk analysis (risk assessment and management), and the criterion of sustainability. Both are found to be potentially arbitrary due to the difficulty in defining the individual constituents necessary to relate environmental phenomena to environmental policy. To place the difficulties in a practical context, this paper presents research results from three recent projects concerned with contaminants in sludge (phosphorus, flocculant polymers, and polymer-surfactant aggregates), and uses the findings to exemplify the dilemma encountered in policy making. A path forward is proposed.
The fundamentals of wastewater sludge characterization and filtration
Authors: Scales P.J. , Dixon D.R. , Harbour P.J. , Stickland A.D.
Published: May 2018

The move to greater emphasis on the disposal of wastewater sludges through routes such as incineration and the added cost of landfill emplacement puts high demands on dewatering technology for these sludges. A clear problem in this area is that wastewater sludges are slow and difficult to dewater and traditional methods of laboratory measurement for prediction of filtration performance are inadequate. This is highly problematic for the design and operational optimisation of centrifuges, filters and settling devices in the wastewater industry. The behaviour is assessed as being due to non-linear behaviour of these sludges which negates the use of classical approaches. These approaches utilise the linear portion of a t versus V2 plot (where t is the time to filtration and V is the specific filtrate volume) to extract a simple Darcian permeability. Without this parameter, a predictive capacity for dewatering using current theory is negated.
Pilot study of a fluidized-pellet-bed technique for simultaneous solid/liquid separation and sludge thickening in a sewage treatment plant
Authors: Wang X.C. , Jin P.K. , Yuan H.L. , Wang E.R. , Tambo N.
Published: May 2018

A fluidized-pellet-bed separator with movable sludge hoppers was applied in pilot scale for the separation and thickening of activated sludge mixture liquid. Under the condition of suspension SS around 4,000 mg/L, polymer (CJX103, cationic, MW 5 × 106) dose at a dry solid ratio of 0.003 and upward flow rate at 5.4 m/hr, the fluidized pellet bed performed solid/liquid separation and sludge thickening well. The SS concentration of the treated water was about 5 mg/L on average and the moisture content of the sludge after screening for 5 min was less than 94%, which is much lower than that after conventional settling and thickening and easy to be finally disposed. At a higher upward flow rate of 7.2 m/hr, similar results could also be obtained but higher polymer dose (solid ratio of 0.004) was required. The morphological characteristics and density-size relationship of the granular particles formed in the fluidized pellet bed were also investigated by image analysis and settling velocity measurement of individual particles. The two-dimensional fractal dimension was evaluated to be 1.6-1.8, showing a good quasi-spherical morphology of the granular particles with their density much higher than the conventional flocs. The results of the pilot study indicate a possible way to innovate the conventional secondary settling and gravitational thickening processes for solid/liquid separation and sludge handling, especially for small scale wastewater treatment plants to reach the goal of space saving and higher treatment efficiency.
Sludge pre-treatment with pulsed electric fields
Authors: Kopplow O. , Barjenbruch M. , Heinz V.
Published: May 2018

The anaerobic stabilization process depends - among other things - on the bio-availability of organic carbon. Through pre-treatment of the sludge which leads to the destruction of micro-organisms and to the setting-free of cell content substances (disintegration), the carbon can be microbially converted better and faster. Moreover, effects on the digestion are likely. However, only little experience is available in sludge treatment with pulsed electric fields. Laboratory-scale digestion tests have been run to analyse the influence of pulsed electric fields on the properties of sludge, anaerobic degradation, sludge water reload and foaming of digesters. The results will be compared with those of other disintegration methods (high pressure homogeniser, thermal treatment). The effect of pre-treatment on the sludge is shown by the COD release. Degrees of disintegration have been achieved up to 20%. The specific energy input was high. The energy consumption has been decreased by initial improvements (pre-heating to 55¡C). The filament bacteria were partially destroyed. The foam reduction in the digesters was marginal. The anaerobic degradation performance has been improved in every case. The degradation rate of organic matter increased about 9%. Due to the increase of degradation, there is a higher reload of the sludge-water with COD and nitrogen compounds.
Full scale validation of helminth ova (Ascaris suum) inactivation by different sludge treatment processes
Authors: Paulsrud B. , Gjerde B. , Lundar A.
Published: May 2018

The Norwegian sewage sludge regulation requires disinfection (hygienisation) of all sludges for land application, and one of the criteria is that disinfected sludge should not contain viable helminth ova. All disinfection processes have to be designed and operated in order to comply with this criterion, and four processes employed in Norway (thermophilic aerobic pre-treatment, pre-pasteurisation, thermal vacuum drying in membrane filter presses and lime treatment) have been tested in full scale by inserting semipermeable bags of Ascaris suum eggs into the processes for certain times. For lime treatment supplementary laboratory tests have been conducted. The paper presents the results of the experiments, and it could be concluded that all processes, except lime treatment, could be operated at less stringent time-temperature regimes than commonly experienced at Norwegian plants today.
The influence of operating experiences in the design of the IVAR thermal drying plant expansion in Stavanger, Norway
Authors: Tornes O. , Whipps A.
Published: May 2018

The Regional Wastewater Treatment Plant of North J¾ren (IVAR IKS) serves the Stavanger conurbation with a population equivalence of 240,000. The site was the first in Norway to operate a thermal drying and a pelletising plant for municipal sludge. Since the start up in 1992, IVAR has encountered most of the operational problems typically associated with thermal drying processes. Considerable modifications have been made and lessons learnt resulting in the plant being one of the few thermal drying facilities in Norway which continues to operate successfully. In general, thermal drying is often considered as a costly, energy demanding and complex process requiring careful attention to safety aspects such as risks of self-combustion, fires and dust explosions. The paper presents general considerations of operating experiences influencing the procurement and design stage of the new extended IVAR thermal drying plant. Furthermore, topical issues important for resolution of thermal drying problems are also discussed. Mass and energy balances for the Stavanger plant are presented.
Structure and microbial composition of nitrifying microbial aggregates and their relation to internal mass transfer effects
Authors: Wilén B.-M. , Gapes D. , Blackall L.L. , Keller J.
Published: May 2018

This paper presents an analysis of the structure and microbial composition of nitrifying aggregates, formed as either flocs or granules, in sequencing batch reactors (SBR) operated with a high ammonium load. The structure and microbial community of the aggregates was determined by fluorescence in situ hybridisation (FISH). The aggregate structure and size was related to mass transfer limitations observed by measurements of OURs measured by either a titrimetric and off-gas analysis sensor (TOGA) or by microsensors. The FISH analysis showed that the spatial arrangement of the microbial consortia correlated well with the oxygen gradients inside the aggregates. In the larger aggregates, the ammoniumand nitrite-oxidising bacteria were mainly concentrated to the outer 100–200 μm, whereas in the floc system, the bacteria were distributed throughout the entire aggregate. This indicates that the internal mass transfer resistance is considerably larger when the aggregate size increases which is directly supported by TOGA measurements.
Two-stage SBR for treatment of oil refinery wastewater
Authors: Lee L.Y. , Hu J.Y. , Ong S.L. , Ng W.J. , Ren J.H. , Wong S.H.
Published: May 2018

A two-stage sequencing batch reactor (SBR) system was used for treatment of oily wastewater with COD and oil and grease (O&G) concentrations ranging from 1,722–7,826 mg/L and 5,365–13,350 mg/L, respectively. A suitable start-up protocol was developed using gradual increase in oily wastewater composition with methanol as the co-substrate. This strategy enabled a short acclimation period of 12 days for the sludge in the two-stage SBR to adapt to the oily wastewater. After acclimation, the 1st stage and 2nd stage SBRs were able to achieve COD removals of 47.0 ± 2.4% and 95.3 ± 0.5%, respectively. The 1st stage SBR was able to achieve 99.8 ± 0.1% of O&G removal and effluent O&G from the 1st stage SBR was only 6 ± 2 mg/L. The 2nd stage SBR was used to further remove COD in the effluent from the 1st stage SBR. The final effluent from the 2nd stage SBR had a COD concentration of 97 ± 16 mg/L with no detectable O&G content. Thus, a two-stage SBR system was shown to be feasible for treating high strength oily wastewater to meet the local discharge standards.
Route to synthesize the sludge management processes
Authors: Lee D.J. , Liu J.C.
Published: May 2018

A route for the synthesis of the treatment train of sewage sludge is proposed, and the conceptual design stage is demonstrated, using local sludge as an example.
Sludge settling processes in SBR-related sewage treatment plants according to the Biocos method
Authors: Meusel S. , Englert R.
Published: May 2018

This paper describes the investigations in a sedimentation and circulation reactor (SU-reactor) of a three-phase Biocos plant. The aim of these investigations was the determination of the temporal and depthdependent distribution of suspended solid contents, as well as describing the sludge sedimentation curves. The calculated results reveal peculiarities of the Biocos method with regard to sedimentation processes. In the hydraulically uninterrupted (pre-)settling phase, a sludge level depth was observed, which remained constant over the reactor surface and increased linearly according to the sludge volume. The settling and the thickening processes of this phase corresponded to a large extent to the well-known settling test in a onelitre measuring cylinder. During the discharge phase, the investigated settling rate was overlaid by the surface loading rate and the sludge level changed depending on the difference between those two parameters. The solid distribution of the A-phase indicated a formation of functional zones, which were influenced by the surface loading. The formation was comparable to the formation of layers in secondary settling tanks with vertical flow. The concentration equalisation between the biological reactor and the SU-reactor proved to be problematic during the circulation phase, because a type of internal sludge circulation occurred in the SU-reactor. A permanent sludge recirculation seems to be highly recommendable.
New developments in sensor technology for water quality surveillance and early warning
Authors: Alcock S.J.
Published: May 2018

Sensor technologies offer particular advantages for surveillance, early warning and process control. This work aimed to provide information about practical new sensing devices that can be used for rapid field assessment of water pollution. A questionnaire completed in 2002 gathered information and data for a catalogue of sensors and instruments that can potentially be applied to soils, sediments, surface and groundwater. Demonstrations of practical sensing technologies took place at a former metal mining site near to Sevilla in 2002, and focusing on diffuse pollution in Koblenz in 2003. These exercises have confirmed that sensors and analytical methodologies can be applied on site to determine various analytes. The instruments provided information useful to manage existing water pollution problems. Some of the scientific innovations of the newest technologies consisted of improved sensitivity, the improved relevance of assays based on biomarkers, the reduced impact on the environment and the capability to detect new contaminants. Sensor technologies were also found to be useful to detect the effects of pollutant mixtures. The portability of these instruments is advantageous for on site and in situ analyses. They will help industry and regulators to deal with existing pollution and attain good water quality.
Water quality modelling of Jadro spring
Authors: Margeta J. , Fistanic I.
Published: May 2018

Management of water quality in karst is a specific problem. Water generally moves very fast by infiltration processes but far more by concentrated flows through fissures and openings in karst. This enables the entire surface pollution to be transferred fast and without filtration into groundwater springs. A typical example is the Jadro spring. Changes in water quality at the spring are sudden, but short. Turbidity as a major water quality problem for the karst springs regularly exceeds allowable standards. Former practice in problem solving has been reduced to intensive water disinfection in periods of great turbidity without analyses of disinfection by-products risks for water users. The main prerequisite for water quality control and an optimization of water disinfection is the knowledge of raw water quality and nature of occurrence. The analysis of monitoring data and their functional relationship with hydrological parameters enables establishment of a stochastic model that will help obtain better information on turbidity in different periods of the year. Using the model a great number of average monthly and extreme daily values are generated. By statistical analyses of these data possibility of occurrence of high turbidity in certain months is obtained. This information can be used for designing expert system for water quality management of karst springs. Thus, the time series model becomes a valuable tool in management of drinking water quality of the Jadro spring.
Characterization of microparticles in raw, treated, and distributed waters by means of elemental and particle size analyses
Authors: Inoue T. , Matsui Y. , Terada Y. , Baba K. , Matsushita T.
Published: May 2018

The elemental composition and particle size distribution of suspended particles in raw water, treated water, and distributed water were determined to understand the behavior of particles during the water treatment-distribution process. The weight of suspended particles collected on a 0.6-µm filter was 1.1 times (raw water), 1.4 times (treated water), and 1.5 times (distributed water) that collected on a 2.7-μ;m filter, suggesting that smaller particles may remain after conventional water treatment. Organic suspended particles were removed less efficiently than inorganic suspended particles. After sand filtration, the Al content in the fixed suspended solids (FSS) markedly increased, indicating that either a small percentage of aluminium floc passed through during sand filtration or dissolved aluminum precipitated after sand filtration. The Mn and Fe concentrations increased after chlorination. The percentages of carbon and nitrogen in the volatile suspended solids (VSS) were roughly the same in the raw, treated, and distributed waters. The carbon/nitrogen/phosphate/VSS ratios indicated that the VSS of the suspended particles consisted of organic matter originating from microorganisms. The major constituents of the FSS in the treated and distributed waters were compounds of Fe, Al, Ca, Mg, and Mn, but these compounds accounted for only 16% or less of the FSS in raw water, indicating the existence of Si compounds. In distribution pipes, the total suspended solids concentration, especially the FSS concentration, was higher than that of water just after treatment. The Fe concentration in distributed water increased, probably due to oxidation and rusting of iron pipes.
Colloidal transport and agglomeration in column studies for advanced run-off filtration facilities - particle size and time resolved monitoring of effluents with flow-field-flowfractionation
Authors: Siepmann R. , von der Kammer F. , Förstner U.
Published: May 2018

The efficiency of road run-off filtration facilities based on ion-exchange materials is reduced by pollutants which are transported bound to particles. To quantify the factors governing particle transport phenomena, a simplified model consisting of quartz sand-filled columns representing the filter/soil was set up. Suspensions of artificial clays, cold water-extracted natural clays, and real run-off were used as model effluents. Five experiments were performed: breakthrough of a natural soil suspension, remobilization of a natural soil suspension after ionic strength-drop, the same two experiments with a suspension of the artificial clay mineral Laponite, and the remobilization of run-off accumulated on a column at high ionic strength with an ionic strength down-gradient. Short-interval effluent fractions were analysed by flow-field-flowfractionation (F4) to obtain the size distributions of the colloids present. The size distributions of subsequent fractions were then plotted in a staggered arrangement to give three-dimensional graphs that are time- and particle size-resolved. With this method the subsequent release of different agglomerate sizes formed on the column could be shown for the artificial clay mineral, questioning its use as a model colloid. The combined particle size- and time-resolved plots proved to be a powerful tool for monitoring colloidal solids in column effluents.