bluuebunny/crossref_metadata_2025_split huggingface dataset:
Control Parameter Variations in an Anaerobic Fluidised Bed Reactor Subjected to Organic Shockloads
Authors: Mathiot S. , Escoffier Y. , Ehlinger F. , Couderc J. P. , Leyris J. P. , Moletta R. 
Published: May 2018

A pilot fluidised bed reactor was subjected to shockloads using wine distillery wastewater. The parameters' response was recorded. Parameters analysed in the gaseous phase were : H2, CH4, CO2 and gas production; in the liquid phase : pH, temperature, TOC and VFA.
Different shockloads were applied : short but intensive shockloading, long shockloadings; temperature variations; change of nature of substrate (wine distillery wastewater was replaced by glucose). Generally speaking, the parameters' response was short (less than one hour).
The specific parameters of the gaseous phase and pH can be used for the optimal control of the fermentation process.
Thermophilic Anaerobic Digestion of Vinasse in Pilot Plant UASB Reactor
Authors: Souza M. E. , Fuzaro G. , Polegato A. R. 
Published: May 2018

Vinasse from sugar-cane alcohol production is generated in great amounts in Brazil and is disposed on soil “in natura”. Only a few distilleries use mesophilic anaerobic digestion, so far, for gas recovery and vinasse treatment or conditioning, due to an unfavorable economical balance.
Thermophilic anaerobic digestion was studied in a large-scale pilot-plant (75 m3 UASB reactor), since vinasses are generated at high temperatures, and no experiments on this subject are reported in the literature, except for a few laboratory assays using pure substrates and other wastewaters.
This work demonstrates the feasibility of sugar-cane vinasse thermophilic anaerobic digestion in UASB reactors.
The reactor was operated for 280 days, as far as possible like a full-scale plant; at applied organic loading rates of 25-30 kg COD/m3.day, 72% COD removal and 10 Nm3gas/m3.day could be achieved. Granulation of the sludge was essential in order to maintain good stability of the process; almost no soda was necessary for pH control.
For full-scale implementation, re-start of the thermophilic process, after several months without feeding, has to be studied yet.
Anaerobic Degradation of Municipal Wastes in Landfill
Authors: Attal A. , Akunna J. , Camacho P. , Salmon P. , Paris I. 
Published: May 2018

The objective of this study was to analyze the degree of decomposition of municipal solid waste (MSW) placed in a landfill site and, based on this analysis, to propose an investigatory procedure to be used to assess the energetic potential of any site.
A sampling technique was developed in order to reduce the size of the MSW sample to 25-30 kg with an acceptable error of 20 %. Profiles of the strata were established which have shown a well ordered structure in horizontal layers corresponding to different MSW ages. The location of the two drill holes were chosen consequently. A sample per MSW age was carried out for each drill hole. Their degradation states were measured using an accelerated biodegradability test which also gives the methane potential.
For all samples, the evolution of four parameters, temperature, % CH4, % VSS and methane potential, were analysed as a function of their age. Anaerobic microbial activity was detected in the top layer of the landfill, showing that refuse starts as soon as deposited to undergo anaerobic transformation. Indeed, the % CH4 reaches its maximum value of 60 % between 5 and 10 m. Temperature increases from about 26°C to 50°C in the first 15 m and stays at this maximum value. That shows that municipal wastes are degraded under mesophilic and thermophilic conditions.
Two relations between waste age and % VSS, and waste age and the energetic potential have been demonstrated. The % VSS represents about 65 % of the dry mass for the fresh wastes and is quite low for the 6 year-old refuse. This rapid waste transformation rate could be due to optimal conditions for anaerobic activity existing in the landfill. The methane potential is proportional to waste age, almost zero for the 6 year-old refuse and greater than 45 1.kg.−1 for fresh wastes. These results show that a simple and rapid measurement of the % VSS of an unknown sample could be a good indication of its age and its degradation state.
As a result of this study, a two-step procedure has been developed that enables an evaluation of the energetic potential of a landfill site. The first step is to collect all the general information on the site, thus providing an initial estimate of the decomposition degree within the mass of the waste. The second step is then to confirm this estimation by sampling and analysing a few samples taken at shallow depths.
Characterization of Suspended Solids in Urban Wet Weather Discharges
Authors: Chebbo G. , Bachoc A. 
Published: May 2018

The objective of this study is to reach a better understanding of the main characteristics of urban stormwater discharge pollution, by providing information on:–paniculate pollution, its importance in relation to dissolved pollution and its abatement through decantation,–the grain size, the specific mass and the settling velocity of these solids.
The first part of this paper is given over to the presentation of the sites chosen and of the experimental methods put into operation.
In the second part we go on to analyze the results obtained for ten rainfall events over four different sites, according to their geographical position, to the type of network and to the size of the catchment basin. It is quite clear from the results obtained that the solids are the main vector of pollution. These solids are very fine (median diameter = 25 to 44 µn) and generally have a very high settling velocity (median settling velocity = 4 to 11 m/h). Thus it can be stated that decantation represents an efficient method to combat the pollution in urban stormwater discharge and this has been proved experimentally.
The Use of Micro/Ultrafiltration for the Removal of Oil and Suspended Solids from Oilfield Brines
Authors: Zaidi A. , Simms K. , Kok S. 
Published: May 2018

Brine generated at offshore and onshore oil recovery facilities is generally treated for removal of oil and suspended solids to meet process and regulatory requirements. Microfiltration (MF) and Ultrafiltration (UF) have been proposed as effective and cost-competitive alternatives to conventional oil removal technology.
Recent studies in this field were reviewed to identify current trends and technical obstacles to the implementation of MF/UF technology for oilfield brine treatment. The most extensively demonstrated membrane technology for oilfield brine treatment in North America is a tubular ceramic microfiltration system which employs backflushing and chemical pretreatment. Two commercial installations of this technology are now in place, however, long term viability is uncertain.
Lack of an adequate database on both membrane/brine interaction and long term system operations have mitigated against the development of predictive models and correlations necessary to design membrane processes for removal of oil from oilfield brine. The key technical obstacles to cost effective application of membranes include low average flux rates, flux degradation and uncertain membrane life. Concerns regarding integration of membrane processes at oilfield brine treatment facilities include sensitivity to variations in flow and oilfield brine characteristics, handling of waste streams generated using chemical pretreatment and requirements for extensive prefiltration.
Polar Organic Pollutants on Their Way from Waste Water to Drinking Water
Authors: Schröder H. Fr. 
Published: May 2018

The examination of pollutants in waste-, surface- and drinking water by sum parameters like COD, BOD or TOC gives no information about their toxicity or behaviour in the drinking water treatment process. As many pollutants leaving sewage treatment plants are polar and/or thermolabile, gas Chromatographic (GC) separation coupled on-line with a mass spectrometer (MS) is not applicable to this problem. Newly established analytical methods like high performance liquid chromatography (HPLC) in on-line combination with mass- (MS) or tandem mass spectrometers (MS/MS) using soft ionization techniques like thermospray (TSP) would help to solve these problems.
The comparison of GC- and LC/MS-spectra demonstrates increasing polarity beginning at the waste water treatment and ending at the drinking water treatment. It was possible to identify and quantify selected compounds, and elimination efficiency could be reviewed by comparing overview spectra.
The knowledge about the existence of these compounds in waste-, surface- and drinking water requires strategies for elimination, avoidance or degradation.
Ecotoxicological Contribution for the Economic Evaluation of Water Pollution Control Strategies
Authors: Vighi M. 
Published: May 2018

A strategy for the control of environmental pollution should be based on three fundamental steps: a- assessment of the environmental aspects of the problem (exposure to pollutant chemicals, damages to man and the environment, etc ); b- economic evaluation (costs and benefits from chemical usage, evaluation of damages, etc ); c- institutional aspects (adoption of environmental standards, regulations, etc. ). Thus, an efficient collaboration between environmental and social sciences is of paramount importance in environmental decision making. To reach this objective it is essential to know exactly what kind of information can be produced by each science.
In this paper an integrated ecotoxicological approach, able to produce descriptive as well predictive results, is presented. Its application to an exercise of collaboration between ecotoxicology and socio-economical sciences is discussed. From this point of view, the case history of herbicide contamination of groundwater in Italy is described.
Study of the Nature of the By-Products Formed and the Risks of Toxicity when Disinfecting a Secondary Effluent with Ozone
Authors: Langlais B. , Legube B. , Beuffe H. , Doré M. 
Published: May 2018

Among the disinfection processes of urban waste water, ozonation and UV irradiation are fast gathering interest. To avoid what happened with chlorine it is necessary to have a look at the formation of by-products and the risks of toxicity when such processes are used. We were already working on this type of problem in 1984, although we did not make a point of communicating in extenso the results obtained during a 2-year period of pilot plant and laboratory studies at La Roche sur Yon (Vendée, France). The present paper reminds of the changes in chemical nature of the effluent after an ozonation from 6 to 12 g O3/m3 resulting in an abatement of fecal coliforms and fecal streptococci to the extent of 3 to 4 logarithmic units. No evidence of compounds known for their toxicity was brought to light.
The toxicity tests performed on fish (Brachydanio rerio) and crustacean (Artemia nauplii) showed that the secondary effluent upstream or dowstream of the ozonation did not have toxic effects on the used biological material except for the fish when strong ammonia nitrogen concentrations occur. The toxicity tests performed on green algae (Scenedesmus subspicatus) showed that ozonated effluent seemed less conductive to algal growth than non ozonated effluent.
Biological or Chemico-Physical Landfill Leachate Purification - An Alternative or a Useful Combination
Authors: Kettern J. T. 
Published: May 2018

The passing of the “General Administrative Regulations on Minimum Requirements for the Discharge of Sewage to Waters”, and particularly Annex 51, has far-reaching implications for landfill leachate treatment. The administrative regulations prescribe limits which entail treatment according to good engineering practice and state-of-the-art technology.
The paper describes leachates from different types of landfill, discusses state-of-the-art leachate treatment technology and presents some recent developments.
The Implementation of Biological Phosphorus and Nitrogen Removal with the Bio-Denipho Process on a 265,000 PE Treatment Plant
Authors: Einfeldt J. 
Published: May 2018

A process, called Bio-Denipho, for combined biological phosphorus and nitrogen removal in a combination of an anaerobic tank and two oxidation ditches is described. In this process the anaerobic tank consisting of three sections working in series is followed by two oxidation ditches. These too are working in series, but with both inlet to and outlet from the tanks changing in a cycle.
The Bio-Denipho process is described specifically for the process itself and as a case study for the implementation of the process on a 265,000 pe wastewater treatment plant for the city of Aalborg in Denmark. The plant was designed and erected in two stages and the last stage was inaugurated October 31,1989. Lay-out and functions for the plant is described and design loads, plan lay-out and tank volumes are given in this paper together with performance data for the first year in operation.
The Influence of Operating Experience on Wastewater Treatment Plant Design in San Francisco, California, USA
Authors: Loiacono J. , Pitt P. , Jenkins D. , Cockburn T. 
Published: May 2018

Three main areas will be covered regarding the design and operation of a pure oxygen activated sludge plant.
Air entrainment occurred in RAS and influent lines and gas entrainment occurred at the sixth stage effluent weirs in an enclosed pure oxygen aeration basin. This caused the oxygen feed to be shut off due to overpressurization and resulted in a combination of high apparent O2 usage and high vent gas purities. The use of an anaerobic selector for Nocardia control is discussed. Anaerobic digester operation has been adversely affected by Nocardia-dominated waste activated sludge. The effect of thick anaerobic digester foams on the ability to pump digested sludge is discussed.
Anaerobic-Aerobic Treatment of High-Strength Ammonium Wastewater - Nitrogen Removal via Nitrite
Authors: Abeling U. , Seyfried C. F. 
Published: May 2018

The two-stage anaerobic-aerobic treatment is applied by preference for the purification of high-concentrated industrial wastewaters. With regard to the elimination of nitrogen compounds by denitrification the far-reaching reduction of organic carbon during the anaerobic pre-treatment is problematic.
A new process of nitrification/denitrification via nitrite wais found to be available in half-technical experiences with high operation security. The carbon consumption amounts only to 60 % in comparison with denitrification via nitrate. The essential parameter for regulating the process is the concentration of free ammonia in the reactor. Concentrations of 1 to 5 mg NH3/l inhibit the nitratation but not the nitritation. The content of ammonia was controlled by means of continuous NH4− and pH-measuring. The inhibition limit for denitrification was found to be at 0.13 mg HN02/l.
Strategies for Optimized Nitrate Reduction with Primary Denitrification
Authors: Londong J. 
Published: May 2018

Full-scale tests carried out for the extension of a 700 000 PE treatment plant are used to show the consequences of advanced denitrification requirements. Three nitrate recirculation strategies were tested: feedback control via the nitrate content at the denitrification zone outflow, control via the redox potential and adaptive control of the recirculated nitrate load in accordance with the input of biodegradable materials, estimated on the basis of a BOD-MS measurement (3 minute BOD).
In a situation in which advanced, process-stable primary denitrification has to be carried out in a restricted space, especially in large treatment plants, controlled nitrate recirculation oriented on the requirement for biodegradables is a feasible method. If denitrification is limited by lack of biodegradable substrate, supplements in line with denitrification requirements will be needed. The necessary control can be implemented via a measurement of BOD-M3 in the influent and measurement of nitrate content in the effluent from the activated sludge tank.
A Novel Approach to Removing Refractory Organic Compounds in Drinking Water
Authors: Yasui H. , Miyaji Y. 
Published: May 2018

A basic study has been conducted on the treatment of refractory organics in river water in order to produce safe drinking water. Through ozonation of refractory organics, assimilable carboxylic acids are produced with a slight decrease in total organic carbon(TOC) concentration. The amount of newly formed assimilable organic carbon corresponds to nearly 35% of the initial TOC in sample water.
Re-ozonation after biological treatment of the formed assimilable organics makes it possible to reduce TOC to a much lower level by transforming the residual refractory organic carbon to an assimilable one. The repeated treatment of ozonation-biodegradation processes can minimize TOC and trihalomethane formation potential to below the detectable level with a minimum of ozone consumption.
Two-Stage Coalescer for Oil/Water Separation
Authors: Sokolovic S. , Secerov-Sokolovic R. , Sevic S. 
Published: May 2018

Many different types of coalescers are used for separation of oil-in-water dispersion.
The investigated results of a newly developed two stage coalescer are given in this work.
The proposed designofthis coalescer includes two independent stages which are set in the same coalescer body.
Expanded polystyrene granules are being used in the first stage.
By using this coalescent material, gravity separation and the large oil droplets, coalescence processes are at the same time being insured.
The second stage of this new type of coalescer uses polyurethane foam.
The surface of this layer has been previously oiled. the proposed two stage coalescer has been tested for different type of oily wastewaters.
A high loaded oilywastewater has been treatedby the new coalescer separator in the field
In a one year working period, a mean oil separation efficiency has been higher than 98 %.
The proposed coalescer can be use for suspended solids separation at the same time. Mean separation efficiency has been 85% duringthe field test.
Solids Concentrations in a Treatment Plant Effluent
Authors: Defrain M. , Schmidt F. 
Published: May 2018

In the calculations customarily used to dimension nitrification and denitrification plants in the Federal Republic of Germany, solids in the influent of the biological stage represent a significant output variable. Numerous modified methods based on nationally and internationally standardized analysis procedures are available to determine solids concentrations in waste-water. Tests showed that different values are measured depending on the method of analysis employed. Harmonization of the analysis procedure is advisable to ensure comparable conditions for the calculation of activated sludge tank volumes.
The solids reaching a treatment plant originate from two main sources. Filterable materials are passed to the treatment plant via the preceding sewerage network with its industrial and commercial users, but are also carried by process water from sludge treatment. The influence of process water on wastewater composition is illustrated by reference to the Wuppertal-Buchenhofen treatment plant.
Natural Design and Maintenance of Rivers and Streams: Targets, Features and Conclusions
Authors: Göttle A. 
Published: May 2018

Most rivers and streams in Europe have been regulated in the past. By this way the most biologically active parts of the landscape and ecological system, the habitat pattern and the species diversity fell victim to regulatory measures. Natural river design or engineering means giving an optimum consideration to natural conditions in order to conserve, improve or restore the ecological quality of river systems and its flood- plains.
The fundamental features of ecological improvement and restoration are discussed especially the ecological unit, variety of biotopesapproved to natural dynamics of the river system, individuality and continuity. Of great importance are detailed ecological inventory and great variation in channel plan, cross section and slope. The experiences with natural stabilization measures and the importance of vegetation as a regular element in river design are shown.
The planing procedures in Bavaria and the ecological and landscape issues are discussed. It has been shown that all available interests and knowledge must be integrated in the best way in an early stage of planning process. The success of natural river engineering works depends on a well balanced solution of all interests, specially trained personnel and enough space for natural variation of river.
Unifying the Theory of Thickening, Filtration, and Centrifugation
Authors: Tiller Frank M. , Hsyung N. B. 
Published: May 2018

Solid/liquid separation operations involve relative movement of solids and liquids in both slurries and porous compactible beds. Thickening, filtration, and centrifugation are governed by the simultaneous flow of liquid through and compaction of porous paniculate beds. In the relative motion, the liquid may have a higher velocity than the solids as in filtration or the reverse as in thickening and sedimentation. Movement of liquid is accompanied by a simultaneous collapse of the structure of the cakes and sediments under mechanical, centrifugal, gravitational, and fluid induced frictional stresses.
A unified approach to solid-liquid separation with cake formation requires the solution of two simultaneous equations. The first rate equation (Darcy-Shirato) involves the gradient of the liquid pressure and the velocity of the liquid relative to the solid. The second stress balance equation contains the gradients of both the liquid pressure and the induced stress on the solid matrix. Neither of these equations can be solved independently. Elimination of the liquid pressure gradient between the equations leads to the particulate structure equation whose solution establishes the cake structure and leads to formula for calculating solid and liquid rates.
If gravitational or centrifugal sedimentation precedes cake formation, a first order hyperbolic partial differential equation governs the suspension concentration and the flux of solids at the cake surface.
Continuous Consolidation of Sludge in Large Scale Gravity Thickeners
Authors: Frost R. C. , Halliday J. , Dee A. S. 
Published: May 2018

Improved design and performance of continuous thickeners should be achieved through a better understanding of the sludge transport processes involved and the variability of sludge thickenability. A software package called PHOENICS was used to model the three-dimensional flow of sludge in the transport zone of a 20m diameter thickener. A mass transport efficiency was evaluated to test the efficacy of the ploughing system, and tracer simulations were performed to study the degree of back-mixing induced. Interpretation of the results suggests that:○Optimum orientation of the ploughs to the radial arm is 60° to 70°.○Transport of sludge to a central outlet occurs principally in the wake of the advancing ploughs, and that ploughs are less efficient than conventional theories dictate.○Sludge in the ploughing zone is mixed, thus potentially impairing thickener performance.
The thickenability of mixed raw sludge arising at a large activated sludge works was monitored. Pronounced seasonal variations were observed, with a marked deterioration in thickenability in late summer and autumn. These were confirmed in trials of a 20m diameter continuous thickener. Consequently the proposed thickening strategy for this works has been revised.