bluuebunny/crossref_metadata_2025 huggingface dataset:
Groundwater treatment at the former gas work remediation site “griftpark” in utrecht, the netherlands. Results of the semi permanent testing facility
Authors: Oesterholt F. I. H. M. , Pluim M. P. , de Vries P. W.
Published: May 2018

A newly built pilot plant system consisting of four different treatment streets, two of which have a biological character, and the other two a physical/chemical character, has been intensively tested during a period of almost one year. These tests are expected to last until August 1996. The objective of the investigation is to find the economically and technologically optimal configuration of treatment steps. This should finally result in the choice and design of a permanent treatment system.

The coagulation/flocculation/sedimentation techniques, as a part of the physical/chemical treatment systems proved to be very unstable, unreliable and very difficult to control. Stable operation conditions were reached only during a few days. Removal efficiencies were very low.

The activated sludge system as well as the biofilm system had very high performance rates. For most of the components very high removal efficiencies could be reached. The addition of PAC to the activated sludge caused a slight increase of the removal efficiencies. UV/ozone tested as a cracking process between two biofilm reactors did not show any improvement. Also the use of UV/ozone as a post treatment system was not very successful.
Sustainability of municipal wastewater treatment
Authors: Roeleveld P. J. , Klapwijk A. , Eggels P. G. , Rulkens W. H. , van Starkenburg W.
Published: May 2018

In this study the insustainability of the treatment of municipal wastewater is evaluated with the LCA-methodology. Life-Cycle Assessments (LCA) analyze and assess the environmental profile over the entire life cycle of a product or process. The LCA-methodology proved to be a proper instrument to evaluate the wastewater treatment plant on the sustainability. However, environmental impacts which are caused by sludge handling should still be classified. Besides that, the LCA should be carried out on regional level instead of on national level. In a situation of high nutrient removal the contribution of the treatment of municipal wastewater to the total insustainability level in the Netherlands is relatively low. When the sustainability of the WWTP has to be improved, the most attention has to be paid to the minimization of discharge from pollutions with the effluent and minimization of the sludge production. Because the contribution of energy consumption is relatively low, less attention can be paid to the minimization of the energy demand. The building of a WWTP and the use of chemicals are not determining the insustainability of the WWTP.
Identification and measurement of pastes rheological properties – effects of water dissociation
Authors: Poitou A. , Racineux G. , Burlion N.
Published: May 2018

Sewage sludges exhibit in most cases rheological properties which do not allow us to classify them either as simple fluids or as solids. On one hand, they are not simple fluids because of their non-Newtonian, shear-thinning and time-dependent (thixotropic or rheopectic) behaviour and because of the possibility for some of them of showing a yield stress. On the other hand, they can hardly be considered as solids, mostly because of their high sensitivity to velocity and because they are practically very often pumped as if they were fluids. This intermediate state sometimes referred to as paste state is in fact very common and is extensively studied, from a manufacturing point of view in areas like ceramics, food or polymer processing and from a civil engineering point of view in soil mechanics for the determination of clay rheology. Many experimental tests have already been designed for their characterisation. The aim of this presentation is to compare some of them and try to make a synthesis between the engineering rheology and soil mechanics approaches.

For this purpose we show experimental results on the same material with different rheometric devices: viz (i) a tube (or capillary) ROSAND rheometer, (ii) a triaxial soil mechanics cell, (iii) an oscillatory, stress driven, plane and plane STRESSTECH rheometer, and (iv) a specific squeezing device which has been designed here following an idea introduced by Laun for polymers. The triaxial cell and the plane and plane rheometers are similar in the sense that they are supposed to allow for an homogeneous state of stress and strain (or rate of strain). In contrast, the tube or squeezing test does not allow for a homogeneous mechanical state. This means that the first two tests enable a real measure of the constitutive relation but in limited conditions while the two others provide a way to identify rheological parameters in flow conditions which are close to the process conditions. The main originalities of this presentation are (i) the balanced point of view between the fluid and the solid mechanics approach and (ii) the method by which the contact properties of the paste is measured with the tube and the squeezing rheometer, giving evidence of a water migration inside the paste.
The rheological experiment in sludge properties research
Authors: Sozanski Marek M. , Kempa Edward S. , Grocholski Krzysztof , Bien January
Published: May 2018

The paper presents research results on rheological properties of a precipitated waterwork sludge. The water content of the sludge studied varied from 100 to 85 per cent at temperatures of 273-293 K, respectively. The sludge in question can be classified as a plastic-viscous fluid, described by the Bingham model. Some empirical relations describing the influence of the water content on τ0 and ηpl have been found. The mentioned parameters were also affected by temperature. The paper describes in detail, technical applications such as the flow of sludge in pipes, as well as the flow along the bottom of sedimentation tanks.
An activated sludge process without excess sludge production
Authors: Sakai Yoshio , Fukase Tetsuro , Yasui Hidenari , Shibata Masahide
Published: May 2018

An activated sludge process which produces no excess sludge was developed. The process is very simple as a small amount of return sludge is ozonated and then returned to the aeration tank. The ozonation enhances biodegradability of activated sludge, which is biologically oxidized in the aeration tank.

A full-scale plant for treating 450m3/d of municipal wastewater was constructed and has been operated successfully for 9 months. The amount of excess sludge eliminated is directly proportional to the amount of ozone dosed to the sludge. At the ozone dosing rate of 0.034 kg/kg-SS, complete elimination of excess sludge has been achieved when 4 times more amount of sludge is ozonated than that of the excess sludge expected in the treatment without ozonation. After 5 months of operation without any withdrawal of excess sludge, small amount of inorganic substances like sand and silt accumulated in the sludge. On the other hand, inert organic substances does not seem to accumulate. As for effluent quality, BOD and nitrogen were kept good. Although effluent SS was 2–15 mg/l higher compared to a control without ozonation, it has been well below the discharge limit.
Utilization of sewage sludge ashes in the brick and tile industry
Authors: Wiebusch Bernd , Seyfried Carl Franz
Published: May 2018

Several aspects of using ashes from sewage sludge incineration in the brick and tile industry have been examined. After discussing the item of ash production in Germany, the impact of different wastewater treatment methods is described; for instance, the use of precipitation agents containing iron will considerably influence the ash quality. Depending on their respective chemical composition, different ashes have different effects on the ceramic qualities of the bricks made of clay blended with ashes. These effects will be shown in regard to the major ceramic parameters. Similarly, the quality of the ashes also influences the elution behaviour and the mineral fixation of heavy metals.
Development of sludge treatment and disposal strategies for large conurbations: case study – Warsaw
Authors: Hall Jeremy E. , Zmyslowska Anna
Published: May 2018

The development of appropriate strategies for the treatment and disposal of sewage sludge is a major problem for all conurbations throughout the world. Sludge treatment and disposal not only represents half of the total costs of municipal wastewater collection, treatment and disposal, but it is also strongly regulated, more so than almost any other form of waste, and readily attracts adverse media and public attention. Thus the challenge for wastewater authorities is to find affordable, sustainable and safe approaches to sludge management, which are also publicly acceptable. This paper describes the Best Environmental Option (BPEO) approach to identifying optimum sludge treatment and disposal strategies and its application to the sludge management problems of city of Warsaw and the surrounding region.
Kinetics of polymeric substrate (dextrin or peptone) removal by activated sludge: hydrolysis of polymers to monomers is the rate-determining step
Authors: Ubukata Yuu
Published: May 2018

Most of the organic compounds in primary effluent are polymers such as proteins and polysaccharides. However the bacteria present in activated sludge (AS) can only directly take up monomers such as amino acids and glucose which are produced from polymers by hydrolysis. Therefore, it is assumed that the hydrolysis of polymers to monomers by the bacteria is the rate-determining step in polymer removal. In this study, AS was acclimated to dextrin or peptone, and polymers (dextrin or peptone) and monomers (glucose or a mixture of free amino acids) were used as substrates for kinetic tests. The removal of monomers and polymers by the AS followed zero- and pseudo first-order reaction kinetics, respectively. The removal rate of monomers was higher than that of polymers, and the oxygen uptake rate of the AS during monomer removal was higher than that during polymer removal. One of the important differences between the polymers and monomers used in this study is whether glycosidic linkages or peptide bonds exist in the material. It was therefore verified that the hydrolysis of polymers to monomers by AS was the rate-determining step in polymer removal. The removal of polymers apparently followed first-order reaction kinetics at high F/M ratios, but nth-order reaction kinetics at low F/M ratios (n>1), which are commonly used in municipal sewage treatment.
Coagulation of textile secondary effluents with Fenton's reagent
Authors: Kang Shyh-Fang , Chang Huey-Min
Published: May 2018

This study was designed to use both artificial and real textile secondary effluents to evaluate (1) the COD and color removal efficiencies for ferrous coagulation and Fenton's coagulation, and (2) the feasibility of using hydrogen peroxide to improve ferrous coagulation to meet more stringent effluent standards. The results indicate that the optimum pHs for both ferrous coagulation and Fenton's preoxidation processes range between 8.0–10 and 3.0–5.0, respectively. The rate for color removal is faster than that for COD removal in the Fenton's preoxidation process. The removals of COD and color are mainly accomplished during Fenton's preoxidation step. The ratio of COD removal for Fenton's coagulation versus ferrous coagulation, given the same ferrous dosage, ranges from 1.4 to 2.3, and it ranges from 1.1 to 1.9 for color removal, using two effluent samples. Therefore, using hydrogen peroxide can enhance the ferrous coagulation, and this ensures more stringent effluent standards of COD and color are met.
Treatment of landfill leachates: ammonia removal via nitrification and denitrification and further COD reduction via Fenton's treatment followed by activated sludge
Authors: Bae Jae-Ho , Kim Sang-Keun , Chang Hyun-Sik
Published: May 2018

Leachates from a municipal solid waste landfill were treated by anaerobic filter (AF) and two-stage activated sludge (AS) for the removal of ammonia. Nitrification in the first stage AS was efficient, but was unstable with temporary accumulations of nitrite by free ammonia toxicity. With the second stage AS, complete nitrification of ammonia and nitrite was achieved. Denitrification via nitrite occurred with the first stage AS effluent recycle, and the resulting AF effluent NOx concentration was kept lower compared to the case in which denitrification via nitrate only occurred with the second stage AS effluent recycle. This might happen because of low COD/N ratio of the raw leachate, and suggests that denitrification via nitrite may be a valuable option. In AF, denitrifiers out-compete methanogens for COD. Ammonia-removed leachate was treated with Fenton's reagents followed by post-AS for further COD removal. Fenton's treatment reduced COD by 63%. Up to 74 mg/L of COD was removed when 100 mg/L of sucrose was added to post-AS. With the above treatment system, 1400∼1800 mg/L of NH4-N was completely removed, leaving 200 mg/L of nitrate nitrogen. Also, 4000∼7000 mg/L of COD in the raw leachate was reduced to 150∼200 mg/L.
Treatment of petrochemical wastewater by UV/H2O2 photodecomposed system
Authors: Juang Lain-Chuen , Tseng Dyi-Hwa , Yang Shyh-Chaur
Published: May 2018

The potential advantages of the UV/H2O2 process treating petrochemical wastewater as the tertiary treatment or the direct pre-treatment were demonstrated. While the high alkalinity of wastewater was not reduced, the UV/H2O2 process as the tertiary treatment could not obtain removal efficiency of wastewater. If the system pH adjusts to 3, this process will polish the effluent of the current biological process to meet the National Effluent Standards of 1998. The results of the direct pre-treatment with the UV/H2O2 process revealed that the recalcitrant compounds presented in raw wastewater would be destroyed to small molecules and might reduce some degree of activity inhibition to bioculture. In the detoxified investigation of spiking aromatic compounds, this process could obtain a good removal efficiency, including a lot of COD removal and the complete detoxification.
Development of simulation system to combine production process and wastewater treatment: calibration of bleached kraft process model through dissolved organic matter in fibreline
Authors: Luonsi Antero , Halttunen Sakari
Published: May 2018

Simulation models for bleached kraft and activated sludge processes are being developed to be used simultaneously for integrated pollution prevention and control (IPPC). In this paper, only the simulation model (modified PROCELL) calibration for bleached kraft process is discussed. The simulation model was calibrated with dissolved organic matter (DOM) using dissolved volatile solids (DVS) values and operational information of a mill. Calibrated DOM in carryover and filtrate throughout the fibreline differed by 10% or less from the measured values in the mill. Complete degradation of DOM to inorganics within the production process is required to make the organic matter balance complete. In the calibrated fibreline, complete degradation of DOM proved to be of the same magnitude as the DOM load from bleaching filtrates (D0 and E1). Complete balance evaluation facilitates the control of the fate of DOM. Data analyzing procedure was developed to determine the basic structure of the DOM (CaHbONc). The information of conventional analyses of DOM such as organic carbon (DOC), DVS and chemical oxygen demand (DCODCr) was developed to elucidate the basic structure of DOM. The degree of oxidation is one feature derived from the structure of DOM. The degree of oxidation seemed to be less in the filtrate than in the carryover in the alkaline stages, while the reverse was occurred in the acid stages.
Resin acid degradation by bacterial strains grown on CTMP effluent
Authors: Zhang Yi , Bicho P. A. , Breuil C. , Saddler J. N. , Liss S. N.
Published: May 2018

All resin acids are diterpenoid carboxylic acids that are components of softwood extractives and they are known to contribute to much of the toxicity of pulp mill effluents. Although biological treatment systems can efficiently remove resin acids during normal operating conditions, resin acid breakthroughs occasionally occur. Recently we isolated five bacterial strains from bleach kraft effluents that degrade dehydroabietic acid (DHA), a resin acid commonly found in effluents. In this study we examined the ability of two bacterial strains (BKME 5 and BKME 9) to grow on chemithermomechanical pulping (CTMP) effluent and degrade DHA. Both of the strains could grow on CTMP effluents, but did not degrade DHA. COD measurement showed that both strains used other organic substrates in CTMP effluent. When nutrients (NH4⊕, PO43−, minerals and vitamins) were added to the effluent, both growth and DHA degradation increased significantly. The strains used DHA and other organic sources in the CTMP effluent simultaneously. The stimulated growth resulting from use of other organic material did not increase the rate of DHA degradation. It was found that ammonium played an important role in the DHA degradation of both strains. Without added ammonium, DHA degradation did not occur. Other nutrients also played important roles in DHA degradation by BKME 9.
Combined treatment of landfill leachate and domestic sewage in a sequencing batch reactor
Authors: Diamadopoulos E. , Samaras P. , Dabou X. , Sakellaropoulos G. P.
Published: May 2018

A study was undertaken to examine the feasibility of biologically treating a combined waste stream of landfill leachate and municipal sewage. The ratio of sewage to leachate was 9 to 1 by volume. The combined waste had an average BOD5 430 mg/l, COD 1090 mg/l, and TKN 133 mg/l (80% of which was in the form of ammonia). A laboratory-scale sequencing batch activated sludge reactor was used to carry comparative performance evaluations of biological treatment, including nitrification and denitrification. The SBR reactor was operating in daily time cycles employing the following sequential operation phases: filling phase, anoxic phase, aeration reaction phase, settling phase, and drain phase. In particular, the anoxic and aeration periods were tailored in order to develop conditions conducive to desired nitrification and denitrification. During the reaction period, the process was operated under an extended aeration mode with the MLSS concentration being around 3500 mg/l. The results indicated that successful biotreatment of combined leachate and sewage was possible, with the treated effluent being low in BOD5 and COD. The system was capable of BOD5 removal efficiencies exceeding 95%. Furthermore, nitrate removal during the anoxic phase was approximately 99% due to denitrification. However, the overall nitrogen removal during a full cycle was about 50%. The inclusion of an anoxic period right after the aeration phase enhanced the nitrogen removal efficiency, yet this phase required the addition of an external carbon source to the reactor due to the low concentration of biodegradable carbon, and at the same time the process became less efficient in BOD removal.
Anaerobic degradation kinetics of 2,4-dichlorophenol (2,4-DCP) with linear sorption
Authors: Ning Z. , Kennedy K. J. , Fernandes L.
Published: May 2018

Degradation of 2,4-DCP by acclimated anaerobic granules enriched at two specific loading rates was examined experimentally in batch mode. The data from process curves were analyzed by nonlinear regression to estimate parameters in the Haldane inhibition equation and one of its modified forms to obtain quantitative information on degradation kinetics. Linear sorption kinetics of 2,4-DCP were employed in data treatment to discriminate between the effects of sorption and biodegradation. It was observed that the modified inhibition equation described experimental data better than the Haldane inhibition equation since the later failed to predict the trend in experimental data. Parameter values estimated with the modified inhibition equation for two types of anaerobic granule, were 0.14 and 0.17 mg/gVSS.h for maximum degradation rate, k; 2.07 and 2.06 mg/L for saturation coefficient, Ks and 65.1 and 67.5 mg/L for inhibition coefficients, respectively. On the basis of 2,4-DCP toxicity effects on the two anaerobic granule types, it was found that the liquid phase concentration determined toxicity and degradation of the chemical.
A new approach to the evaluation of biological treatability of industrial wastewater for the implementation of the “waste design” concept
Authors: Bortone Giuseppe , Gemelli Sabrina , Tilche Andrea , Bianchi Roberto , Bergna Giovanni
Published: May 2018

An intrinsic characteristic of the Italian industrial production system is the presence of several industrial districts with a prevalent manufacturing typology, in which several small and medium enterprises dealing with the same or similar products are concentrated in a small territory. An important textile district is localized in Como area, north of Italy. In many cases, industrial districts are served by large treatment plants that receive the majority of the pollution loading from several small and medium enterprises that do not have internal treatment facilities. The treatment fee is determined by regional regulations; commonly, the single wastewater stream connected to the sewer is billed by the sewer manager to the source industry on the basis of the flow rate and of a complex formula that takes into account a series of parameters. This method is unable to properly evaluate the relationship between treatment fee and actual treatment costs, since conventional physical-chemical and biochemical parameters are not necessarily linked to wastewater treatability. New advanced respirometric methodologies could be used as wastewater characterization techniques, since they are particularly suited to represent the effect of a given wastewater on the final wastewater treatment plant. Hence, they could be better correlated to treatment costs. The instrument developed is composed of two parallel moving bed continuous flow completely mixed reactors of the working volume of about 5 l each, equipped with oxygen sensors connected to a computer that acts as a controller and as a data acquisition and processing unit. Some examples of experimental results obtained with synthetic waste and with real sewage are presented.
Homogeneous oxidation of phenols in aqueous solution with hydrogen peroxide and ferric ions
Authors: Grigoropoulou H. , Philippopoulos C.
Published: May 2018

The chemical oxidation of phenol and chlorophenols with hydrogen peroxide in the presence of soluble iron can be economically attractive at low oxidant consumption, leading then to intermediates that are more easily biodegradable. The homogeneous oxidation of phenol and chlorophenols in aqueous solutions with hydrogen peroxide is studied at oxidant : phenol ratio of about 4:1 and 16:1 (mol/mol) at various catalyst concentrations, at ambient temperature without pH control. Ferric chloride, ferric and ferrous sulphate and ferrous ammonium sulphate are used as oxidation catalysts. Ferric salts induce higher oxidation rates than ferrous ones and the nature of the anions present does not affect reaction rate. 4-Chlorophenol is found to be most resistant to oxidation and 2,4,6-Trichlorophenol is not attacked by hydrogen peroxide in the presence of ferric ions at the experimental conditions studied.
Solid substrate anaerobic co-digestion of paper mill sludge, biosolids, and municipal solid waste
Authors: Poggi-Varaldo H. M. , Valdés L. , Esparza-García F. , Fernández-Villagómez G.
Published: May 2018

The Mexican pulp and paper industry and municipal authorities are facing increasing regulatory and cost-related pressures regarding the handling, treatment and disposal of waste sludge and solid wastes. The dry anaerobic digestion (DASS) is a promising alternative for the co-stabilization of waste sludge, municipal and industrial solid wastes. However, appropriate and fast process start-up is a bottleneck for the dissemination of DASS technology in developing countries. This work aimed at determining a reliable and fast DASS start-up procedure from non-anaerobic inocula for the digestion of a mixture of paper sludge, waste sludge and municipal solid waste. Three types of inoculum were used: cattle manure (CM), soil (S) and waste activated sludge (WAS). Results were analyzed in terms of the stabilization time Te (the time required to develop a full methanogenic regime) and the overall start-up time To (time required to reach at least 25% TS inside the reactor since the inoculation). A factorial experiment was implemented; factors were the inoculum type (five combinations of CM, S and WAS), temperature (35 and 55°C) and loading rate (4.5 and 8.2 g VS/kg.d). Results showed that the fastest start-up was obtained with reactors using inoculum I3 (33% CM, 33% S and 33% WAS) at 55°C and 8.2 g VS/kg.day loading rate. Interestingly, thermophilic regime favoured shorter stabilization times, in spite of the fact that the inocula used were meso- or psychrophilic. Results from DASS reactors that reached steady state after start-up (I3 and I4) showed typical performance responses of 60% removal efficiency (% total VS basis), biogas productivity between 2.7-3.5 NL/kg wrm.day, a in the range 0.3-1.3 and pH around 8. This suggested that the DASS process is a feasible alternative for co-digesting paper-mill sludge, MSW and biosolids.
Growth responses of periphyton and chironomids exposed to biologically treated bleached kraft pulp mill effluent
Authors: Dubé M. G. , Culp J. M.
Published: May 2018

Experiments were conducted in artificial streams to determine the effects of increasing concentrations of biologically treated bleached kraft pulp mill effluent (BKPME) on periphyton and chironomid growth in the Thompson River, British Columbia. Periphyton growth, as determined by increases in chlorophyll a, was significantly stimulated at all effluent concentrations tested (0.25%, 0.5%, 1.0%, 5.0% and, 10.0%). Chironomid growth (individual weight) was also significantly stimulated at low effluent concentrations (≤1.0%). At higher concentrations (5.0% and 10.0%), chironomid growth was inhibited relative to the 1.0% treatment streams. Increases in growth were attributed to the effects of nutrient and organic enrichment from BKPME. The effluent contained high concentrations of phosphorus and appears to be an important source of carbon for benthic insects grazing on the biofilm. In high concentration effluent streams, chironomid growth decreased despite low levels of typical pulp mill contaminants. This suggests that other compounds in the effluent, such as wood extractives, may be inhibiting chironomid growth. These results support findings of field monitoring studies conducted in the Thompson River where changes in periphyton and chironomid abundance occurred downstream of the bleached kraft pulp mill.
Characterization of effluents from chlorine dioxide substitution bleaching and oxygen-reinforced extraction
Authors: Yetis Ulku , Ataberk Selale , Gokcay Celal F. , Sahin Sebnem M.
Published: May 2018

The effects of chlorine dioxide substitution for elemental chlorine in the chlorination stage, aimed at the minimization of chlorinated organics and subsequent oxygen reinforcement in the proceeding extraction stage on the characteristics of bleaching effluents have been examined. The characteristics of the effluents were assessed in terms of molecular weight distribution by gel filtration, so that alternatives for the treatment of these effluents can be proposed. The analysis of chlorination and extraction stage effluents with different chlorine dioxide substitution levels and varying available chlorine charges by using a Sephadex G-50 column have indicated that indeed a marked change in the molecular weight distribution of chlorinated organic compounds have occurred. The molecular size of chlorinated organic compounds in the chlorination stage has increased with the chlorine dioxide substitution, while that in the extraction stage has decreased when compared with the molecular size of these compounds in original bleaching effluents with only elemental chlorine used in the chlorination stage and followed by extraction stage. Molecular size of the chlorinated organic compounds in the chlorination stage effluents was not seriously affected by the chlorine dioxide substitution level; while it was increased greatly by the increased total chlorine dosage. In the extraction stage effluents, chlorine dioxide substitution level has not appeared to be an important parameter influencing the molecular size distribution.
Strength characterisation of microbial granules
Authors: Pereboom J. H. F.
Published: May 2018

The strength of microbial granules is still poorly understood. The granule strength is defined as the resistance to attrition and/or breaking by a mechanical force or the liquid shear stress. The strength of various types of microbial granules were studied. The objective was to develop an in vitro strength characterisation test and to be able to predict granule behaviour in full scale systems. Abrasion experiments were conducted in stirred tanks and bubble columns, while the influence of viscosity and medium composition, shear rate and particle size were studied.

The medium viscosity did not influence the relation between shear rate and abrasion. Measurements in demineralized water or media containing complexing agents resulted in lower granule strengths presumably the result of the removal of calcium from the granule matrix. In bubble columns attrition is the predominant abrasion process. In full scale reactors, e.g. UASB, attrition is apparently insignificant. In stirred tanks also granule breakage was observed. The abrasion rate is not directly related to the stirrer tip speed. Larger methanogenic granules showed more abrasion compared to small ones. In contrast larger nitrifying granules were stronger than small ones.

A standardized strength characterization test was developed to be able to compare strengths of different microbial granules. The strength of slow growing systems appeared to be higher as compared to fast growing systems. From an ecological point of view, cells growing slowly in continuous operated systems gain advantage from attachment and shear resistance or strength.
Anaerobic degradation kinetics of particulate organic matter: a new approach
Authors: Valentini Andrea , Garuti Gilbert , Rozzi Alberto , Tilche Andrea
Published: May 2018

The development of a reliable model of anaerobic hydrolysis is of primary importance for improving modeling and design of anaerobic treatment for wastewaters and slurries with high suspended solids concentration. Michaelis-Menten, substrate first order, substrate and biomass first order and substrate first order and biomass half order equations have been compared using experimental data from a series of anaerobic degradation batch tests on cellulose particles of known size.

A general kinetic equation [dS/dt=−KHASXA] which may include all the four considered kinetics, is presented. This general equation allows for a more accurate mathematical representation of the hydrolysis process. Analysing data from a series of batch tests, the best fit value of A was found to be in the range 0.42 to 0.64. This approach could reduce the choice of anaerobic degradation kinetics of particulate organic matter to the calculation of the kinetic constant KHA and of the related power coefficient A.
Modeling of hydrogen behavior and reduced product formation following perturbation with hydrogenic substrate in a methanogenic reactor
Authors: Furumai Hiroaki
Published: May 2018

The purposes of this study are to develop a non-steady state model which can express hydrogen behavior and reduced products formation in a perturbed methanogenic CSTR and to investigate energetic and kinetic interaction such as hydrogen transfer between H2 producers and consumers. Smith and McCarty (1989a, 1989b) obtained interesting experimental results on transient responses of the perturbed mixed-culture methanogenic CSTR receiving ethanol and propionate. In an experiment with a sudden addition of propionate and ethanol at steady state, they observed highly elevated H2 pressure and formation of reduced products such as propanol and longer chained VFAs. The model was applied to the perturbation experiment introducing a new concept of H2 transport between bacterial groups. Different H2 concentrations are defined by making a hydrogen transport within a colony of H2 producers and consumers. The modified model expressed the sudden change of H2 pressure and the formation of the reduced intermediate products which brought relatively low H2 concentration. Once kinetics and energetic of biochemical reactions are given, the model could be available for transient processes and for better understanding of interactions Between H2 producers and consumers.
Kinetics of anaerobic cometabolism of 2,4-dinitrotoluene with ethanol as the primary substrate
Authors: Cheng Jiayang , Suidan Makram T. , Venosa Albert D.
Published: May 2018

A kinetic model that describes the anaerobic cometabolism of 2,4-dinitrtoluene (DNT) with ethanol as the primary substrate has been developed based on experimental results. The kinetic parameters were estimated using the Levenberg-Marquardt algorithm. 2,4-DNT is anaerobically biotransformed to 2,4-diaminotoluene (DAT) via 4-amino-2-nitrotoluene (4-A-2-NT) and 2-amino-4-nitrotoluene (2-A-4-NT) by the bacteria whose growth is supported by utilizing ethanol. 2,4-DNT shows inhibition to its own biotransformation. It also exhibits a very strong competitive inhibition to further biotransformation of 4-A-2-NT and 2-A-4-NT. All the aromatics in the system, 2,4-DNT, 4-A-2-NT, 2-A-4-NT, and 2,4-DAT, inhibit the conversion of ethanol. Hydrogen produced from the acetogenesis of ethanol is utilized for the transformation of the nitroaromatics. The utilization of hydrogen and acetate by methanogenic bacteria is very strongly inhibited by the presence of the nitroaromatics. Acetate exhibits strong competitive inhibition to the biodegradation of propionate.
Removal of hydrogen sulfide from an anaerobic biogas using a bio-scrubber
Authors: Nishimura Sosuke , Yoda Motoyuki
Published: May 2018

A novel biological treatment process for removing hydrogen sulfide from anaerobic biogas using a bio-scrubber has been developed. The treatment process is composed of a gas/liquid contact tower and an aeration tank. The biogas from an anaerobic wastewater treatment process is introduced into a multiple-bubble-tray contact tower (bio-scrubber) and scrubbed with activated sludge liquor from an aeration tank. The sludge liquor containing sulfides is then returned to the aeration tank, where the sulfide is oxidized to sulfate by sulfur-oxidizing bacteria such as Thiobacillus. The contact tower is designed to be air tight in order to prevent air from mixing into the biogas used as a fuel. A simulation model was developed to calculate effluent gas concentrations from the contact tower, incorporating input parameters such as influent hydrogen sulfide concentrations, gas flow rates, and gas/liquid ratios. Using the simulation model, design criteria were calculated and a full-scale plant for treating biogas from a UASB process for potato processing wastewater was constructed. The data shows that the hydrogen sulfide in the biogas was effectively reduced from 2,000 ppm to less than 20 ppm.
Anaerobic fluidized beds: ten years of industrial experience
Authors: Holst T. C. , Truc A. , Pujol R.
Published: May 2018

The Anaflux process, an upflow anaerobic fluidized bed reactor using a mineral bacterial support, has been employed industrially for ten years treating a variety of food-processing and paper industry wastewaters. This paper describes five aspects of the design and operation of the anaerobic fluidized bed which have proven, from industrial experience, to be essential. The optimization of these factors enables a stable functioning of the process and allows the application of high loading rates. Included are the results of a semi-industrial pilot study, treating wine distillation wastewaters, which demonstrate the present capabilities (OLR=70 kg COD/m3·d) of this type of reactor.
Energy loss at surcharged manholes - model experiment
Authors: Sakakibari Takashi , Tanaka Shuji , Imaida Toshihiro
Published: May 2018

This study aims to evaluate the energy loss at manhole. Experimental model with straight pipes (D=0.2 m for diameter, 18.5 m for length) and four rectangle-shaped manholes (0.26 m for width, Dm=0.12 m for length) was used. Energy losses at manholes, Δ H, were determined as the difference of hydraulic gradient lines at the center of the manhole extended from both upper and lower side of pipes. The energy loss coefficient was given as K=(Δ H)(2g)/v2. Obtained coefficients converged their range from 0.02-0.12 to 0.04-0.06, according to the increase of the water velocity. We concluded that the reason of this comparatively smaller K values was due to the smaller diameter ratio; Dm (manhole diameter or length)/D(pipe diameter), compared to the results of other experiments.
Characteristics of sediments from a stormwater management pond
Authors: Marsalek J. , Marsalek P. M.
Published: May 2018

Physical and chemical characteristics of bottom sediment from an on-stream stormwater pond were described by the depth of sediment accumulations, particle size distribution, water content, concentrations of total metals, and distribution of metal fractions determined by a sequential analysis. Except for a sand/gravel spit by the creek inflow, bottom sediments comprised silt and clay, with high water content (up to 80%, by volume), and accumulated at a rate of 0.02 m·yr−1 (bulk sediment depth). Sediments contained elevated levels of heavy metals, among which the levels of Cr, Cu and Pb caused the greatest environmental concerns. Furthermore, sequential analysis indicated that up to 70 - 90% of total metals in these sediment was in potentially mobile forms. Without further treatment, these sediments could not be reused in urban areas, nor readily disposed at municipal landfills.
Guidelines for hydrodynamic calculations on urban drainage in the Netherlands: overview and principles
Authors: van Mameren Harry , Clemens François
Published: May 2018

This article presents the results of a major project in The Netherlands with the objective to give guidelines for hydrodynamic calculation in urban drainage. The guidelines are based on rainseries simulation using a hydrodynamic calculational technique. The new guidelines do not prescribe a certain software package, but merely define defaults and procedures. They also put constraints on input and output data. The new guidelines are introduced in The Netherlands by the end of 1995 and will be evaluated in 1998 using the practical experience acquired by municipalities, waterboards and consulting engineers.
Coping with uncertainties in integrated urban water management
Authors: Geldof Govert D.
Published: May 2018

In the practice of integrated water management we meet complexity, subjectivity and uncertainties. Uncertainties come into play when new urban water management techniques are applied. The art of a good design is not to reduce uncertainties as much as possible, but to find the middle course between cowardice and recklessness. This golden mean represents bravery. An interdisciplinary approach is needed to reach consensus. Calculating uncertainties by using Monte Carlo simulation results may be helpful.
Monitoring and modelling in urban drainage
Authors: Price R. K. , Catterson G. J.
Published: May 2018

A holistic appreciation of the performance of an urban drainage network is needed to understand how best to extend, operate and maintain the asset. These functions are best achieved through the recognition of the complementary roles of monitoring and modelling. A model is needed for planning structural changes to a network. Confirmation of both model asset data and model calibration requires long term as well as short term monitored data. In the future, engineers will make better use of the synergy between monitoring and modelling.
Measures to promote stormwater infiltration
Authors: Fujita Shoichi
Published: May 2018

In Japan, infiltration facilities have been constructed systematically and enthusiastically at many construction sites, such as, roads, parks, houses, schools, rivers, and sewers. In this study, methods for spreading stormwater infiltration are proposed by making use of these experiments and achievements of stormwater infiltration. At first, the problems concerning stormwater infiltration are introduced. Secondly, measures for spreading stormwater infiltration are considered, and in fact, stormwater infiltration technology is spread by these methods.
Pollution of soil and groundwater from infiltration of highly contaminated stormwater - a case study
Authors: Mikkelsen P. S. , Häfliger M. , Ochs M. , Jacobsen P. , Tjell J. C. , Boller M.
Published: May 2018

A surface and a sub-surface infiltration system that received runoff water from trafficked roads for several decades was dug up and the contamination with heavy metals, PAH and AOX was investigated. Most measured solid phase concentrations exceeded background concentrations in nearby surface soils and sub-surface sediments and some even exceeded guidelines fixed to preserve the fertility of soil. However, the contamination decreased rapidly with depth. None of the measured metal concentrations in simulated soil solutions exceeded defined drinking water quality standards. Surprisingly, the surface and the sub-surface infiltration system seemed to be equally good at retaining pollution. This indicates that the runoff sludge found in such infiltration systems plays an important role both as a source and a sorbent for stormwater contaminants. The study does not point at a considerable risk for groundwater contamination due to stormwater infiltration, but highlights that well absorbable contaminants readily available in urban stormwater runoff eventually build up in surface soils and sub-surface sediments to environmentally critical concentration levels. Thus, on the one hand stormwater infiltration systems may act as effective pollution traps and on the other, they may pose a potential solid waste disposal problem that future stormwater management based on local infiltration will have to face.
Pollution based real time control strategies for combined sewer systems
Authors: Weinreich Gabriela , Schilling Wolfgang , Birkely Ane , Moland Tallak
Published: May 2018

This paper presents results from an application of a newly developed simulation tool for pollution based real time control (PBRTC) of urban drainage systems. The Oslo interceptor tunnel is used as a case study. The paper focuses on the reduction of total phosphorus Ptot and ammonia-nitrogen NH4-N overflow loads into the receiving waters by means of optimized operation of the tunnel system. With PBRTC the total reduction of the Ptot load is 48% and of the NH4-N load 51%. Compared to the volume based RTC scenario the reductions are 11% and 15%, respectively. These further reductions could be achieved with a relatively simple extension of the operation strategy.
The management and treatment of combined storm flows in Jersey
Authors: Shepherd G. , Johnson D.
Published: May 2018

This paper addresses processes and strategies used to minimise the frequency of foul water overflows to sea. Conventional and unconventional storage structures are described together with new techniques used to improve the quality of final effluent flowing from the treatment works.
Health significance of pigmented bacteria in drinking water
Authors: Rusin P.A. , Rose J.B. , Gerba C.P.
Published: May 2018

The purpose of this study was to determine the relative health risks of pigmented bacteria found in drinking water samples. These pigmented bacteria include opportunistic pathogens such as Flavobacterium, Pseudomonas, Corynebacterium, Nocardia, Mycobacterium, Erwinia, Enterobacter, Serratia, and Micrococcus. Flavobacterium meningosepticum is the most clinically important of the flavobacteria but causes <0.08% of meningitis cases in the US. Pseudomonas aeruginosa is an important opportunistic pathogen causing >10% of nosocomial infections. Human feeding tests show that oral doses of 106 to 108CFU results in colonisation of the gastrointestinal (GI) tract but do not produce any morbidity in healthy volunteers. Corynebacteria rarely cause disease except for toxigenic C. diphtheriae which is non-pigmented on R2A agar. The most important member of Nocardia is N. asteroides which is an opportunistic pathogen for certain immunocompromised population segments. National surveys show that only 9.2–19.2% of mycobacterial clinical isolates are pigmented with M. kansasii being the most frequent (4–10%). This bacterium is associated with disease but would not be detected as part of the HPC bacteria using a 7d incubation period. Pigmented strains of Erwinia, Enterobacter, Serratia, and Micrococcus can cause disease but they are relatively unimportant compared to other pathogenic bacteria as shown in ranking studies.
A study on the injury process of escherichia coli induced by chlorine
Authors: Tosa K. , Hirata T. , Taguchi K.
Published: May 2018

In this study, we tried to evaluate the physiological state of E. coli exposed to chlorine by using non-selective media and media supplemented with different concentrations of selective agent. A new kinetic model – transportation equation model – was developed based on the physiological change of bacteria for describing the injury process of E. coli induced by chlorine and applied to the experimental results. Conclusions can be summarised as: 1) physiological state of E. coli exposed to chlorine can be determined by using different selective media; 2) the tolerance distribution of E. coli to sodium deoxycholate shifted to a lower concentration with contact time; 3) the transportation equation model presented in this study agrees with experimental results; and 4) the transportation equation model is applicable to analyse the injury process of E. coli in chlorination.
Evaluation of the disinfection potential of low chlorine concentrations in tap water using immobilised enterococcus faecium in a continuous flow device
Authors: Wiedenmann A. , Braun M. , Botzenhart K.
Published: May 2018

A simple continuous flow device in which bacteria were immobilised on membrane filters and flushed with tap water with free chlorine residuals of 0.05, 0.1, 0.2 and 0.4mg/L at pH 7.7 and 10°C, has been used for disinfection experiments with faecal streptococci. A 99.99% reduction of Enterococcus faecium was observed between 3.4–5.2min (0.05mg/L), between 2.8–4.1min (0.1mg/L), between 1.7–3.1min (0.2mg/L) and between 0.8–2.1min (0.4mg/L). CT-products covered a range of 0.17 (0.05mg/L, lower limit) up to 0.85mg/L/min (0.4mg/L, upper limit). The test system is suggested as a more reliable alternative to batch experiments when the disinfection potential of low chlorine concentrations acting for several minutes has to be evaluated. The system cannot be used to demonstrate exact reduction kinetics but it allows the calculation of CT values and the evaluation of the disinfection potential of chlorinated water at any point of a distribution system where initial chlorine concentrations may have already remarkably declined.