bluuebunny/crossref_metadata_2025 huggingface dataset:
Origins of filter effluent particles: experimental study of particle deposition and detachment
Authors: Kim J. , Tobiason J.E.
Published: May 2018

This paper investigates the relative roles of particle deposition and detachment in controlling the origin of filter effluent particles. A conceptual mathematical model was developed and laboratory-scale experiments were conducted. Laboratory experiments were performed using three sizes of fluorescent microspheres (FMs), to determine the fraction of filter effluent particles that are filter influent particles that were never removed, as well as the fraction of filter effluent particles that were detached after deposition. Experimental results indicated that particle detachment is significant beginning from the early phase of filtration. FM removal increased with filter run time, depth and particle size. For each size FM at one filter depth, FM removal increased with filter runtime to a maximum due to ripening and then decreased with filter runtime after ripening due to limited pore space remaining in the filter. The fraction of effluent particles that were detached particles increased with particle size and filter bed depth.
Particle count and size alteration for membrane fouling reduction in non-conventional water filtration
Authors: Adin A.
Published: May 2018

If coagulation is not completely successful and produces aggregates which are too small, fouling may increase. In some cases, a deep-bed filter could perhaps provide a solution. The paper examines these effects using experimental results for different waters. Activated sludge effluents, stormy seawater containing microalgae and spent filter backwash water (SFBW) were coagulated by alum or ferric chloride. Sand filtration tests were carried out. Tests were performed in a membrane filtration stirred cell, filtration pilot plant equipped with SDI analyzer (seawater) and pilot UF plant (SFBW). For activated sludge effluent, alum residual ratio curves of turbidity and total particle count (TPC) followed one another. With ferric chloride, low coagulant dosage showed negative turbidity removal. Contact granular filtration reduced membrane fouling intensity. Increasing the dose resulted in higher improvement in membrane flux. For seawater, a filter run period under storm conditions reached 35 hours with satisfactory filtrate quality. An iron chloride dose of 0.3 mg/l during normal conditions and 0.5 mg/l for stormy condition should be injected, mixed well before the filters, while maintaining 10 m/hr filtration rate and pH 6.8 value. For SFBW, alum flocculation pretreatment of SFBW was effective in reducing turbidity, TPC, viruses and protozoa. SFBW settling prior to flocculation did not enhance turbidity and TPC removal. The largest remaining particle fraction after alum flocculation was 3-10 μm in size, both Cryptosporidium and Giardia are found in this size range. Coagulation enhanced the removal of small size particles, a positive impact on reducing membrane fouling potential.
Nitrogen removal by recycle water nitritation as an attractive alternative for retrofit technologies in municipal wastewater treatment plants
Authors: Gil K.-I. , Choi E.
Published: May 2018

The recycle water from sludge processing in municipal wastewater treatment plants causes many serious problems in the efficiency and stability of the mainstream process. Thus, the design approach for recycle water is an important part of any biological nutrient removal system design when a retrofit technology is required for upgrading an existing plant. Moreover, the application of nitrogen removal from recycle water using the nitritation process has recently increased due to economic reasons associated with an effective carbon allocation as well as the minimization of aeration costs. However, for the actual application of recycle water nitritation, it has not been fully examined whether or not additional volume would be required in an existing plant. In this paper, the addition of recycle water nitritation to an existing plant was evaluated based on a volume analysis and estimation of final effluent quality. It was expected that using the reserve volume of the aeration tank in existing plants, recycle water nitritation could be applied to a plant without any enlargement. With the addition of recycle water nitritation, it was estimated that the final effluent quality would be improved and stabilized, especially in the winter season.
Nitrogen removal from sludge reject water by a two-stage oxygen-limited autotrophic nitrification denitrification process
Authors: Wyffels S. , Boeckx P. , Pynaert K. , Zhang D. , Van Cleemput O. , Chen G. , Verstraete W.
Published: May 2018

Nitrogen removal from sludge reject water was obtained by oxygen-limited partial nitritation resulting in nitrite accumulation in a first stage, followed by autotrophic denitrification of nitrite with ammonium as electron donor (similar to anaerobic ammonium oxidation) in a second stage. Two membrane-assisted bioreactors (MBRs) were used in series to operate with high sludge ages and subsequent high volumetric loading rates, achieving 1.45 kg N m-3 day-1 for the partial nitritation MBR and 1.1 kg N m-3 day-1 for the anaerobic ammonium oxidation MBR. Biomass retention in the nitritation stage ensured flexibility towards loading rate and operating temperature. Nitrite oxidisers were out-competed at low oxygen and high free ammonia concentration. Biomass retention in the second MBR prevented wash-out of the slowly growing bacteria. Nitrite and ammonium were converted to dinitrogen gas in a reaction ratio of 1.05, thereby maintaining nitrite limitation to assure process stability. The anoxic consortium catalysing the autotrophic denitrification process consisted of Nitrosomonas-like aerobic ammonium oxidizers and anaerobic ammonium oxidizing bacteria closely related to Kuenenia stuttgartiensis. The overall removal efficiency of the combined process was 82% of the incoming ammonium according to a total nitrogen removal rate of 0.55 kg N m-3 day-1, without adding extra carbon source.
ANAMMOX and partial denitritation in anaerobic nitrogen removal from piggery waste
Authors: Ahn Y.-H. , Hwang I.-S. , Min K.-S.
Published: May 2018

The anaerobic ammonium removal from a piggery waste with high strength (56 g COD/L and 5 g T-N/L) was investigated using a lab-scale upflow anaerobic sludge bed reactor at a mesophilic condition. Based on the nitrogen and carbon balance in the process, the contribution of autotrophic and heterotrophic organisms was also evaluated in terms of the influent NO2-N/NH4-N ratio (1:0.8 and 1:1.2 for Phase 1 and Phase 2, respectively). The result of this research demonstrates that the anaerobic ammonium removal from the piggery waste, using the UASB reactor, can be performed successfully. Furthermore, it appears that by using granular sludge as the seed biomass, the ANAMMOX reaction can start more quickly. Average nitrogen conversion was 0.59 kg T-N/m3 reactor-day (0.06 kg T-N/kg VSS/day) and 0.66 kg T-N/m3 reactor-day (0.08 kg T-N/kg VSS/day) for Phase 1 and Phase 2. The NO2-N/NH4-N removal ratio by the ANAMMOX was 1.48 and 1.79 for Phase 1 and Phase 2. The higher nitrite contents (about 50%) in the substrate resulted in higher nitrite nitrogen removal by the partial denitritation, as well as the ANAMMOX reaction, implying higher potential of partial denitritation. However, the result reveals that the ANAMMOX reaction was influenced less by the degree of partial denitritation, and the ANAMMOX bacteria did not compete with denitritation bacteria. The colour of the biomass at the bottom of the reactor changed from dark gray to dark red, which was accompanied by an increase in cytochrome content. At the end of the experiment, red-coloured granular sludge with diameter of 1-2 mm at the lower part of the reactor was also observed.
Activated Sludge Model No. 1 calibration for piggery wastewater treatment using respirometry
Authors: Boursier H. , Beline F. , Paul E.
Published: May 2018

To optimise the intermittent aeration process for piggery wastewater, the Activated Sludge Model No. 1 needs to be calibrated and adapted to this specific effluent. By combining aerobic and anoxic respirometric tests, biodegradation kinetics of organic fractions in piggery wastewater could be studied. Modeling of the respirometric curves proved that the simplified hydrolysis model was sufficient for piggery wastewater treatment simulation. The hydrolysis constant (KH) and heterotrophic sludge yield (YH) were determined at temperature and pH in the ranges 10-40°C and 7-9, respectively. The constants were slightly influenced by the temperature but not significantly affected by the pH, with average values of 3 d-1 for KH, and 0.60 for YH. The anoxic respirometric tests revealed that the experimental ASM1 anoxic correction factor (ηg) was higher than one. This could be explained by the fact that the anoxic and the aerobic heterotrophic sludge yields were probably different. By fixing a value of 0.8 for ηg, the anoxic sludge yield (YHD) could be calculated at 0.53. A modified version of ASM1 for substrate biodegradation in piggery wastewater intermittent aeration process was proposed, including the separation between the anoxic and the aerobic sludge yields and a simplified hydrolysis kinetic.
Agricultural recycling of the by-product concentrate of livestock wastewater treatment plant processed with VSEP RO and bio-ceramic SBR
Authors: Yoon Y. , Ok Y.-S. , Kim D.-Y. , Kim J.-G.
Published: May 2018

One of the problems in a reverse osmosis process for livestock wastewater treatment is disposal of the by-product concentrate. The agricultural recycling of the concentrate is more cost saving than a further treatment. Application of the concentrate reduces the chemical fertilizer amendment. The agricultural recycling of the concentrate from the Kimhae livestock wastewater treatment plant, processed with the VSEP RO and bio-ceramic SBR, was studied. The concentrate includes non-biodegradable humic substance and residual inorganic ions (NH4+, NO3-, PO43-, K+, etc.). The contents of N, P and K were 1,650, 382 and 2,059 mg L-1, respectively. The total acidity of humic acids extracted from the concentrate was 5.17 cmol(+) g-1, composed of 2.38 cmol(+) g-1 of carboxylic group and 2.79 cmol(+) g-1 of phenolic hydroxyl group. Coliforms and E. coli were not detected in the concentrate. The yield of rice plant with the concentrate applied to it resulted in similar production to that with chemical fertilizer applied. The water extractable nitrate content of the concentrate-applied land did not exceed that of chemical fertilizer applied, at soil depths of 30 and 60 cm. The percolated amount of nitrate into the water table in arable land with the concentrate applied showed a similar level to that treated with the chemical fertilizer.
Small water and wastewater systems: pathways to sustainable development?
Authors: Ho G.
Published: May 2018

Globally we are faced with billions of people without access to safe water and adequate sanitation. These are generally located in developing communities. Even in developed communities the current large scale systems for supplying water, collecting wastewater and treating it are not environmentally sustainable, because it is difficult to close the cycle of water and nutrients. This paper discusses the advantages of small scale water and wastewater systems in overcoming the difficulties in providing water and wastewater systems in developing communities and in achieving sustainability in both developed and developing communities. Particular attention is given to technology and technology choice, even though technology alone does not provide the complete answer. Disadvantages of small scale systems and how they may be overcome are discussed.
Innovative technologies for decentralised water-, wastewater and biowaste management in urban and peri-urban areas
Authors: Otterpohl R. , Braun U. , Oldenburg M.
Published: May 2018

Avoiding the comingling of water flows coming from different sources and thus obtaining flows with a very low dilution factor is the first and major step key to technical solutions for adequate treatment of household wastewaters. Through their decentral structure and effective recovery of water, energy and fertiliser these systems can be highly cost efficient. Fresh water consumption can be reduced by up to 80% while nutrients can be recovered to a large extent. Source control is also advantageous for hygienic reasons: low volumes are far easier to sanitise. Source separation technology in municipal waste water treatment does often lead decentralised or semicentral systems. The first essential step is the separate collection and treatment of toilet waste in households, which contains almost all pathogens and nutrients. New toilet systems with very low dilution factors, ranging from vacuum- through urine sorting to dry toilets, have been introduced in several projects and proven feasible. New ideas such as the black- and greywater cycle systems are presently under research at the Technical University Hamburg Harburg. Such modular, integrated and small scale systems are only possible through recent advances in membrane technology and, due to their small scale, do have the potential to be installed in densely populated regions. These technologies are options for following the principles of ecological sanitation, to contain, to sanitise and to reuse also in urban areas (EcoSanRes, 2003).
Evaluation of small wastewater treatment systems
Authors: Hellström D. , Jonsson L.
Published: May 2018

Different technologies for the treatment of wastewater from single houses have been evaluated by performing measurements at 14 treatment plants installed at different one-family houses located 35 km south-west of Stockholm. The technologies tested were selected in order to deliver high removal efficiencies with respect to organic matter, nitrogen and phosphorus. They also had to fulfil requirements concerning robustness, nutrient recycling, use of natural resources, economy, user-friendliness and hygiene. The systems can be divided into package plants, urine separating systems, blackwater separating systems and chemical precipitation as a supplement to sand filter beds. All of the systems were able to remove more than 90% of phosphorus and more than 90% of organic matter. Concerning package plants, it is necessary to have reliable dosing equipment and frequent checks to achieve long-term phosphorus removal. The source separation systems require well-informed and motivated users to achieve desirable removal efficiency. Sorting systems seem to be superior with respect to nitrogen removal, even though some of the package plants gave nitrogen removal above 50% during long periods of operation.
Improved nitrogen removal in upflow anaerobic sludge blanket (UASB) reactors by incorporation of Anammox bacteria into the granular sludge
Authors: Schmidt J.E. , Batstone D.J. , Angelidaki I.
Published: May 2018

Upflow anaerobic sludge blanket reactors may offer a number of advantages over conventional mixed-tank, SBR, and biofilm reactors, including high space-loading, low footprint, and resistance to shocks and toxins. In this study, we assessed the use of upflow anaerobic sludge blanket (UASB) reactor technology as applied to anaerobic ammonia removal, or Anammox. Four 200 ml UASB reactors were inoculated with 50% (by volume) anaerobic granular sludge and 50% flocular sludge from different sources (all with the potential for containing Anammox organisms). Tools used to assess the reactors included basic analyses, fluorescent in-situ hybridisation, and mathematical modelling, with statistical non-linear parameter estimation. Two of the reactors showed statistically identical Anammox activity (i.e., identical kinetic parameters), with good ammonia and nitrite removal (0.14 kgNHx m-3 reactor day-1, with 99% ammonia removal). The third reactor also demonstrated significant Anammox activity, but with poor identifiability of parameters. The fourth reactor had no statistical Anammox activity. Modelling indicated that poor identifiability and performance in the third and fourth reactors were related to an excess of reduced carbon, probably originating in the inoculum. Accumulation of Anammox organisms was confirmed both by a volume loading much lower than the growth rate, and response to a probe specific for organisms previously reported to mediate Anammox processes. Overall, the UASB reactors were effective as Anammox systems, and identifiability of the systems was good, and repeatable (even compared to a previous study in a rotating biological contactor). This indicates that operation, design, and analysis of Anammox UASB reactors specifically, and Anammox systems in general, are reliable and portable, and that UASB systems are an appropriate technology for this process.
Experimental study on nitrification in a submerged aerated biofilter
Authors: Farabegoli G. , Chiavola A. , Rolle E. , Stracquadanio S.
Published: May 2018

The aim of the present work was to evaluate the performance of a semi-pilot scale BAF in order to obtain a highly polished effluent in terms of removal of organic matter, suspended solids and ammonia and to observe the influence of temperature, pH and nitrite accumulation on the nitrification process. The ammonia removal efficiency during summer and winter and the nitrite accumulation in presence of free ammonia were observed. The biomass density was measured at different filter bed heights and the sludge production from the effluent of the backwashing water was evaluated. The results obtained were used to calibrate a mathematical model for the prediction of the ammonia removal profile in the filter bed and of biomass thickness.
Vermiculture as a tool for domestic wastewater management
Authors: Bajsa O. , Nair J. , Mathew K. , Ho G.E.
Published: May 2018

Organic waste management is a growing issue due to the unsustainable practices of its disposal. Sewage treatment plants are designed to treat wastewater to produce a safe effluent. However, one of the by-products, the sewage sludge which is disposed off in landfill or used as fertilizer in agricultural operation is high in pathogens. Sustainability can be achieved by Vermicomposting of organic matter which involves accelerated cycling of nutrients though a closed cycle whereby waste products are put to productive end use. Vermicomposting and vermifiltration are natural waste management processes relying on the use of worms to convert organic wastes to stable soil enriching compounds. Domestic wastewater management can be accommodated through these processes in a sustainable manner. A considerable reduction in pathogens has been noticed in the end product to a level that it can be safely applied to land. This paper provides an overview of the system characteristics of management systems utilising vermiculture, to manage wastewater. The process can be used in a small scale for household waste treatment to rural or urban waste management.
Biological granulated activated carbon fluidized bed reactor for atrazine remediation
Authors: Herzberg M. , Dosoretz C.G. , Tarre S. , Beliavski M. , Green M.
Published: May 2018

To show that an adsorbing biofilm carrier (GAC) can be advantageous for atrazine bioremediation over a non-adsorbing carrier, fluidized bed (FB) reactors were operated under atrazine limiting concentrations using Pseudomonas sp. strain ADP as the atrazine degrading bacteria. The following interrelated subjects were investigated: 1) atrazine adsorption to GAC under conditions of atrazine partial penetration in the biofilm, 2) differences in atrazine degradation rates and 3) stability of atrazine biodegradation under non-sterile anoxic conditions in the GAC reactor versus a reactor with a non-adsorbing biofilm carrier. Results from batch adsorption tests together with modeling best described the biofilm as patchy in nature with covered and non-biofilm covered areas. Under conditions of atrazine partial penetration in the biofilm, atrazine adsorption occurs in the non-covered areas and is consequently desorbed at the base of the biofilm substantially increasing the active biofilm surface area. The double flux of atrazine to the biofilm in the GAC reactor results in lower effluent atrazine concentrations as compared to a FB reactor with a non-adsorbing carrier. Moreover, under non-sterile denitrification conditions, atrazine degradation stability was found to be much higher (several months) using GAC as a biofilm carrier while non-adsorbing carrier reactors showed sharp deterioration within 30 days due to contamination of non-atrazine degrading bacteria.
Treatment of leachate from the anaerobic fermentation of solid wastes using two biofilm support media
Authors: Comett I. , Gonzalez-Martinez S. , Wilderer P.
Published: May 2018

Biofilms growing on different carrier media have a different response to the nutrients contained in wastewater. Biofilms have proven to be an alternative to the treatment of wastewater containing higher concentrations of contaminants. The main objective of this research was to compare two biofilm support media for the treatment of leachate from the anaerobic fermentation of solid wastes. The removal of organic matter and ammonia was achieved in two fixed bed biofilm reactors containing Kaldnes® and Linpor® support materials with specific surface areas of 490 and 270 m2/m3, respectively, and operating under the sequencing batch procedure during 204 days. The Linpor reactor achieved higher total COD removal than the Kaldnes reactor (47% and 39%, respectively). Linpor was shown to be less sensitive to influent COD changes than Kaldnes. The effluent total COD values of Kaldnes were higher than Linpor. The dissolved COD removal was 21% for both reactors. The average ammonia removal for Linpor was 72% and 42% for Kaldnes. The matrix of Linpor allows higher concentrations of microorganisms (as dry mass) than Kaldnes. The dry mass concentration was related to the "active" exposed surface area of the biofilm. This is considered to be the cause for the better performance of Linpor when compared with Kaldnes.
Investigation of sludge re-circulating clarifiers design and optimization through numerical simulation
Authors: Davari S. , Lichayee M.J.
Published: May 2018

In steam thermal power plants (TPP) with open re-circulating wet cooling towers, elimination of water hardness and suspended solids (SS) is performed in clarifiers. Most of these clarifiers are of high efficiency sludge re-circulating type (SRC) with capacity between 500-1,500 m3/hr. Improper design and/or mal-operation of clarifiers in TPPs results in working conditions below design capacity or production of soft water with improper quality (hardness and S.S.). This causes accumulation of deposits in heat exchangers, condenser tubes, cooling and service water pipes and boiler tubes as well as increasing the ionic load of water at the demineralizing system inlet. It also increases the amount of chemical consumptions and produces more liquid and solid waste. In this regard, a software program for optimal design and simulation of SRCs has been developed. Then design parameters of existing SRCs in four TPPs in Iran were used as inputs to developed software program and resulting technical specifications were compared with existing ones. In some cases improper design was the main cause of poor outlet water quality. In order to achieve proper efficiency, further investigations were made to obtain control parameters as well as design parameters for both mal-designed and/or mal-operated SRCs.
An alternate oxic-anoxic process automatically controlled. Theory and practice in a real treatment plant network
Authors: Battistoni P. , Boccadoro R. , Bolzonella D. , Marinelli M.
Published: May 2018

A simple mathematical model of an alternate oxic-anoxic process has been elaborated. It enables us to optimise the cycle time on the basis of maximum nitrates concentration in the effluent and the desired nitrogen removal performance. At the same time the model can be employed to verify the impact of the variations of flow rate and influent characteristics as well as the operational parameters of the process. Actually, the model confirms the process efficiency but its feasibility in real plants needs a local or remote process control. To verify these theoretical conclusions a real wastewater plant (700 PE) has been upgraded in an alternate oxic-anoxic process. It was implemented with software able to elaborate the data of dissolved oxygen concentration and oxidation reduction potential. Moreover, the evaluation of the flexing points was performed to manage mixer and blowers. A one-year experience of plant management allowed us to obtain very high nitrogen removal. However, the performances were different during wet or dry weather periods. The statistical analysis of probe signals evaluation confirmed the capability of the control device to detect the flexing points during the anoxic phase (70-94%). On the other hand, the capability of detecting the DO signal was lower, in particular when the oxygen demand was similar to the amount of supplied oxygen. The hourly variations of flow rate and mass loading determines different conditions for starting the anoxic phase: over aeration, over loading and the equivalence of oxygen demand and supply, are the main factors determining the blowers stopping.
Growth, structure and oxygen penetration in particle supported autotrophic biofilms
Authors: Boessmann M. , Neu T.R. , Horn H. , Hempel D.C.
Published: May 2018

Particle supported autotrophic biofilms were cultivated in external-loop airlift reactors at two different pumice concentrations. Oxygen microelectrodes were used to investigate substrate transport and conversion. A special flow cell was designed for the measurement of oxygen concentration profiles in the particle supported biofilms under defined hydrodynamic conditions. The oxygen concentration profiles inside the biofilms were found to be steeper at high flow velocities in the bulk phase of the flow cell compared to those at low flow velocities. Furthermore, the oxygen flux increased and the thickness of the concentration boundary layer decreased with increasing flow velocity. This dependence was found to be more pronounced in less dense biofilms out of airlift reactors with lower pumice concentrations. In addition confocal laser scanning microscopy (CLSM) was used to visualize the biofilm structure. The volume fractions of bacteria and extracellular polymeric substances (lectin-specific EPS-glycoconjugates) were measured in living fully hydrated biofilms. Both the microelectrode and CLSM measurement showed the influence of shear stress on particle supported biofilms. A higher particle concentration led to dense biofilms with a homogeneous surface, lower thickness of the concentration boundary layer and steeper oxygen concentration profiles. The combination of both techniques allows a detailed and quantitative characterisation of particle associated biofilm structure and function.
Nutrient removal of ammonia rich effluents in a sequencing batch reactor
Authors: Yilmaz G. , Oztürk I.
Published: May 2018

The aim of this study was to develop an appropriate operating strategy for ammonia removal of young landfill leachate in a lab-scale sequencing batch reactor, SBR. SBR was operated at five different phases by changing the aerobic cycle time and external carbon source during the denitrification process. SBR provides the opportunity to arrange the operating periods according to variable conditions such as wastewater characterization in order to optimise the performance of the system. By monitoring the variations occurring in each period during a full cycle an appropriate operating strategy may be defined. The main problem faced during the experimentation period particularly was due to use of raw wastewater with high NH4-N content as an external carbon source, as it affected denitrification performance to a great extent. This trouble was overcome if calcium acetate was used as the external carbon source instead of the raw wastewater. In case of using a suitable aeration period and the convenient external carbon source, high ammonia removals were observed.
Improving nitrogen removal in predenitrification-nitrification biofilters
Authors: Larrea L. , Abad A. , Gayarre J.
Published: May 2018

The effect on NH4-N removal rates in nitrification biofilters of filtered biodegradable COD and particulate COD leaving predenitrification biofilters was studied in a lab scale plant configured with the separated system of biofilters for secondary nitrogen removal from urban wastewaters. Applying a typical COD load of 11 kg/m3.day to the predenitrification biofilter and maximizing its COD removal by adding nitrates or by operating an improved control of the internal recycle, only 60% removal of filtered biodegradable COD was found. This value corresponds to the complete removal of the readily biodegradable substrate (30% of influent filtered COD) and 36% of filtered slowly biodegradable substrate (50% of influent COD). The remaining 64% of the latter entered the nitrification biofilter, causing competition between heterotrophs and nitrifiers for dissolved oxygen in the inner layers of the biofilm. Consequently the nitrification rate had relatively low values (0.5 kgN/m3.d) at 14°C despite using dissolved oxygen levels of 6 mg/l. This behaviour may explain the lower nitrification rates obtained in some cases of nitrification biofilters compared to those in tertiary nitrification after activated sludge processes. The particulate COD entering the nitrification biofilter is associated with the suspended solids leaving the denitrification biofilter which are adsorbed by the external layers of the biofilm, increasing its thickness. The activity of the nitrifiers was affected because of a lack of oxygen when the thickness was left to grow considerably. Therefore no significant particulate COD effect is expected to occur as long as backwashing is carried out with the appropriate frequency.
Winery solid residue revalorization into oil and antioxidant with nutraceutical properties by an enzyme assisted process
Authors: Tobar P. , Moure A. , Soto C. , Chamy R. , Zúñiga M.E.
Published: May 2018

Revalorization of the winery industry residue, grape seed is studied for the production of an oil and defatted meal with nutraceutical properties. Conventional grape seed oil extraction process is carried out by pressing at high temperature affecting the product quality. Oil extraction by cold pressing improves product quality, but it gives a low oil yield. Oil extracted is increased at the pressing stage, when an enzymatic pre-treatment is incorporated in to the conventional process. The yield is determined by determining the residual oil in the pressed cake. Using an enzymatic treatment during 9 hours at 45°C and 50% of moisture, with a mixture of two commercial enzymes grape seed oil extraction yield by cold pressing is raised up to 72%, being a 59.4% increment in comparison to the yield obtained by the control, without enzymes. The defatted meal by enzimatic assisted process improves its phenolic compounds between 2 and 4 times, depending on the conditions of phenolics extraction in comparison to the control samples.
Statistical analysis of pollution in stormwater infiltration basins
Authors: Barraud S. , Dechesne M. , Bardin J.-P. , Varnier J.-C.
Published: May 2018

In order to characterize soil pollution in stormwater infiltration basins, four basins of the Lyon area were selected and sampled. Altogether, 66 soil samples were collected. Each sample was analyzed for pH, cationic exchange capacity, particle size distribution, total organic carbon, total nitrogen, total phosphorus, metals, total hydrocarbons and polycyclic aromatic hydrocarbons (PAHs). Data was explored in a classic way (soil profiles) and using multivariate analysis techniques. Two methods were applied: Principal Component Analysis (PCA) and Cluster Analysis (CA). Main results are presented in this paper. Pollutant concentrations decrease rapidly with depth while pH and grain size increase. Sustainable concentrations are reached at a 50-cm depth, even after 21 years of operation. Multivariate analysis shows how pollution affects each sampling depth.
Effective pollutant retention capacity of permeable pavements for infiltrated road runoffs determined by laboratory tests
Authors: Fach S. , Geiger W.F.
Published: May 2018

The infiltration of urban runoff always implies an entrance of pollutants into the soil and ground water. Due to legal regulations in many communes there is no longer any permission needed for stormwater infiltration, if administrative regulations and the requirements of standards are observed. The results of a research project carried out under the heading “Development of an assessment procedure for permeable pavements” show, that the pollutant retention capacity of permeable pavements varies considerably, depending on the material and the specific reactive surface. The objective of the study was to work out recommendations of suitable permeable pavements for different types of urban runoff. Selected data about the quality of urban runoff was compiled into a runoff matrix, which was used for defining characteristic dilutions. In batch tests, the material of the infiltration devices is penetrated with the dilutions. A test installation in large scale is used to calibrate the sorption coefficients derived from the batch experiment.
Sensitivity to experimental data of pollutant site mean concentration in stormwater runoff
Authors: Mourad M. , Bertrand-Krajewski J.-L. , Chebbo G.
Published: May 2018

Urban wet weather discharges are known to be a great source of pollutants for receiving waters, which protection requires the estimation of long-term discharged pollutant loads. Pollutant loads can be estimated by multiplying a site mean concentration (SMC) by the total runoff volume during a given period of time. The estimation of the SMC value as a weighted mean value with event runoff volumes as weights is affected by uncertainties due to the variability of event mean concentrations and to the number of events used. This study carried out on 13 catchments gives orders of magnitude of these uncertainties and shows the limitations of usual practices using few measured events. The results obtained show that it is not possible to propose a standard minimal number of events to be measured on any catchment in order to evaluate the SMC value with a given uncertainty.
A benchmark methodology for managing uncertainties in urban runoff quality models
Authors: Kanso A. , Tassin B. , Chebbo G.
Published: May 2018

In this paper we present a benchmarking methodology, which aims at comparing urban runoff quality models, based on the Bayesian theory. After choosing the different configurations of models to be tested, this methodology uses the Metropolis algorithm, a general MCMC sampling method, to estimate the posterior distributions of the models' parameters. The analysis of these posterior distributions allows a quantitative assessment of the parameters' uncertainties and their interaction structure, and provides information about the sensitivity of the probability distribution of the model output to parameters. The effectiveness and efficiency of this methodology are illustrated in the context of 4 configurations of pollutants' accumulation/erosion models, tested on 4 street subcatchments. Calibration results demonstrate that the Metropolis algorithm produces reliable inferences of parameters thus, helping on the improvement of the mathematical concept of model equations.
Master planning for stream protection in urban watersheds
Authors: Urbonas B.R. , Doerfer J.T.
Published: May 2018

Urbanization results in great changes to the landscape and the water environment simply because stormwater runoff differs in quantity and quality from the pre-urbanization state. Streams, rivers, lakes, estuaries and other receiving water bodies experience the changes to runoff frequencies and volumes and react accordingly. The forces behind the observed changes in the receiving waters are discussed in this paper and suggestions are made on how to plan to deal with them. Urban watershed and waterway master planning can help to mitigate, in large part, the impacts imposed on these waters by land-use changes. Although each watershed is unique, some general principles are suggested to deal with these emergent problems.
Stormwater quality modelling in combined sewers: calibration and uncertainty analysis
Authors: Kanso A. , Chebbo G. , Tassin B.
Published: May 2018

Estimating the level of uncertainty in urban stormwater quality models is vital for their utilization. This paper presents the results of application of a Monte Carlo Markov Chain method based on the Bayesian theory for the calibration and uncertainty analysis of a storm water quality model commonly used in available software. The tested model uses a hydrologic/hydrodynamic scheme to estimate the accumulation, the erosion and the transport of pollutants on surfaces and in sewers. It was calibrated for four different initial conditions of in-sewer deposits. Calibration results showed large variability in the model's responses in function of the initial conditions. They demonstrated that the model's predictive capacity is very low.
Grain size distribution of metals and polycyclic aromatic hydrocarbons in silt trap sediments from the combined sewer network of Paris (France)
Authors: Moilleron R. , Perez J. , Garnaud S.
Published: May 2018

For three years (2001–2003), sediment samples were extracted from about 100 silt traps (STs) spread out all over the combined sewer network of Paris. These STs, whose volume varied from 21 to 325 m3, were cleaned out as soon as their filling capacities were reached. All these sediment samples were analysed for physicochemical parameters (pH, organic matter (OM) content, grain size distribution), total hydrocarbons (THs), 16 polycyclic aromatic hydrocarbons (PAHs) selected from the priority list of the US-EPA, and heavy metals (Al, Ag, As, Cd, Cu, Cr, Sn, Fe, Mn, Hg, Ni, Pb, Zn). For each silt trap, six sediment samples were extracted before the clean out procedure: three samples were extracted from the sediment surface (5–10 cm depth) and three other samples were extracted from a deeper sediment layer (approximately at 1 m depth). The location of these sampling points allowed us to take into account the possible spatial fluctuation of pollutant loads in each ST. The first results showed that there were some important inter-site variations of pollutant contents. These variations have to be taken into account by the sewer manager for the fate of the ST sediments. Therefore, we decided to assess the grain size distribution of some pollutants. OM, heavy metals and PAHs have been investigated on the five grain size fractions (>20 mm, 8–20 mm, 0.5–8 mm, 50–500 μm, <50 μm) for 9 STs, which have been selected on their heavy metal content basis. This work aims at understanding the distribution of the pollutant contents and at improving the knowledge of the ST sediment pollution.
Model concept for nitrate and nitrite utilization during anoxic transformation in the bulk water phase of municipal wastewater under sewer conditions
Authors: Abdul-Talib S. , Ujang Z. , Vollertsen J. , Hvitved-Jacobsen T.
Published: May 2018

A two-stage anoxic transformation process, involving growth of biomass utilizing two types of different electron acceptors, namely nitrate and nitrite, has been observed. The present water quality modules established for sewer processes cannot account for the two-stage process. This paper outlines the development of a model concept that enables the two-stage anoxic transformation process to be simulated. The proposed model is formulated in a matrix form that is similar to the Activated Sludge Models and Sewer Process Model matrices. The model was successfully applied to simulate changes in nitrate and nitrite concentrations during anoxic transformations in the bulkwater phase of municipal wastewater.
Evaluation of separate urine collection and treatment to augment existing wastewater treatment works
Authors: Wilsenach J.A. , van Bragt W.P.M. , de Been P. , van Loosdrecht M.C.M.
Published: May 2018

Simultaneous increases in wastewater loads and effluent quality demand improved nutrient removal techniques. A simple technique for nitrogen removal is post-denitrification with methanol. The trade-off between better effluent vs. methanol consumption is debatable. Methanol dosing is not only un-sustainable in the long term, but the cost of methanol is also becoming increasingly important. Urine contains 80% of the total nitrogen (N) and 50% of the phosphate in wastewater. Separate collection and treatment of urine could improve existing treatment works and diminish the need for post-denitrification. In this paper, a nitritation-denitrification process is proposed where 20–30% of the N in urine is removed with the COD available in urine. The treated urine consists of ammonium-nitrite, which is to be introduced to the anoxic zone of a conventional treatment plant. Optimal denitrification via nitrite is possible with COD from other wastewater sources. The case study presented here shows that 40–50% urine separation and improvement of the flow scheme would improve effluent quality from 19 to 10 g N/m3, which would eliminate the need for post-denitrification.
Effluent treatment by multi-media filtration, microfiltration and ultrafiltration: results of a pilot investigation at WWTP Hoek van Holland
Authors: te Poele S. , Menkveld W. , Boom J. , van Bragt W.
Published: May 2018

Upgrading of wastewater treatment plant (WWTP) effluent as a part of the Dutch governmental policy to close the water cycle has increasing interest now. The Water Board Hoogheemraadschap van Delfland together with the project team of Witteveen+Bos Consulting Engineers, Delft University of Technology and Rossmark water treatment investigated the reuse possibilities of WWTP effluent in the region of Delfland. Therefore pilot research was carried out at WWTP Hoek van Holland applying different filtration techniques: multi-media filtration, micro- and ultrafiltration. The results show stable process performances of the different filtration techniques when proper pre-treatment was applied. For microfiltration the filtration characteristics were strongly influenced by particles which were not retained in the multi-media filter. For ultrafiltration the filtration characteristics were strongly influenced by organic components <0.2 μm. The upgraded WWTP effluent could not be used directly as process water or for agriculture purposes, due to high concentrations of COD and salts in the WWTP effluent and filtrates. However WWTP effluent or floc filtrate could be applied directly as water for the washing of sea-sand.
Targeting attention on local vulnerabilities using an integrated index approach: the example of the climate vulnerability index
Authors: Sullivan C. , Meigh J.
Published: May 2018

It is known that climate impacts can have significant effects on the environment, societies and economies. For human populations, climate change impacts can be devastating, giving rise to economic disruption and mass migration as agricultural systems fail, either through drought or floods. Such events impact significantly, not only where they happen, but also in the neighbouring areas. Vulnerability to the impacts of climate change needs to be assessed, so that adaptation strategies can be developed and populations can be protected. In this paper, we address the issue of vulnerability assessment through the use of an indicator approach, the climate vulnerability index (CVI). We show how this can overcome some of the difficulties of incommensurability associated with the combination of different types of data, and how the approach can be applied at a variety of scales. Through the development of nested index values, more reliable and robust coverage of large areas can be achieved, and we provide an indication of how this could be done. While further work is required to improve the methodology through wider application and component refinement, it seems likely that this approach will have useful application in the assessment of climate vulnerability. Through its application at sub-national and community scales, the CVI can help to identify those human populations most at risk from climate change impacts, and as a result, resources can be targeted towards those most in need.
Dynamics of rain-induced pollutographs of solubles in sewers
Authors: Rutsch M. , Müller I. , Krebs P.
Published: May 2018

When looking at acute receiving water impacts due to combined sewer overflows the characteristics of the background diurnal sewage flux variation may influence the peak loads from combined sewer overflows (CSO) and wastewater treatment plant (WWTP) effluent significantly. In this paper, effects on the dynamic compounds transported in the sewer, on CSO discharges and WWTP loading are evaluated by means of hydrodynamic simulations. The simulations are based on different scenarios for diurnal dry-weather flow variations induced by different infiltration rates.
Modelling of flushing waves for optimising cleaning operations
Authors: Dettmar J. , Staufer P.
Published: May 2018

In the framework of a German field and numerical study the possibilities of an optimal cleaning by flushing of a combined sewer with storage capacity and bottom-end overflow were investigated. The objective of this combined investigation was to find out the boundaries for the flushing operation to prevent wave reflections and impoundages at the throttle by guaranteeing the necessary shear stress for remobilization.
Precaution, law and principles of good administration
Authors: Fisher E.
Published: May 2018

The precautionary principle is a legal principle concerned with the process of how decisions are made. In implementing and interpreting it regard must be had to the surrounding legal culture and in particular the principles of good administration in operation. Highlighting those principles emphasises that within a particular jurisdiction there is often very little agreement over their nature. Within the European Union contradictory principles are the product of: assumptions about risk problem-solving, the ambiguous nature of European administration, a concern with accountability in the face of recent food controversies, and the impact of international trade rules. These contradictory principles present a number of challenges for implementing the precautionary principle.
Recent development in the field of international liability regimes to tackle environmental risks
Authors: Bally J.
Published: May 2018

The polluter-pays principle requires States to take any actions that may be necessary to ensure that polluters bear the full environmental and social costs of their activities. One step to implement this principle is the development of regulations on environmental Civil Liability. The adoption of the UN-ECE Protocol on Civil Liability and Compensation for Damage caused by the Transboundary Effects of Industrial Accidents on Transboundary Waters (Kiev Protocol) in May 2003 was the result of a three-year negotiation process undertaken in the aftermath of the Baia Mare accident in Romania. The accident caused transboundary water pollution in the downstream countries Hungary and Yugoslavia. Owing to the absence of applicable liability rules, no compensation was ever paid for the damage caused by the pollution. The Cartagena Protocol on Biosafety mandates the Parties to establish rules and procedures in the field of liability and redress. Here there is likely to be a longer negotiation process before an agreed regime on liability and redress for damage arising from the use of living modified organisms (LMOs) becomes available, owing to the complexity and the particularities of gene technology.