bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
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.
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.
Physico-chemical and bacteriological characterization of wastewater from Mexico City
Authors: Jiménez C. Blanca , Landa V. Homero 
Published: May 2018

This study was designed to characterize the behavior of the wastewater produced by Mexico City after being subjected to a physico-chemical treatment of Al2(SO4)3 and FeCl3 in a jar test simulation of an Advanced Primary Treatment (APT). Special attention was paid to the evaluation of the removal efficiency of suspended solids and of helminth eggs. The effluent thus obtained was first subjected to a simulated filtration process (through a fiberglass filter paper with an opening of 11 μm) and then it was disinfected with the use of two chemicals: sodium hypochlorite (NaOCl) and copper sulphate (CuSO4).
The use of both the Al2(SO4)3 (dose ranging from 25 to 40 mg/L) and the FeCl3 (varying from 20 to 40 mg/L) in combination with the filtration process proved to be quite effective in what refers to the removal mechanisms of helminth eggs. The concentrations recorded in each of the effluents fell always below the international regulations for irrigation reuse (&lt;1 org/L as helminth eggs). The removal rates achieved for both coagulants were close to 99%.
In what refers to the disinfection accomplished with the use of NaOCl (from 4 to 17 mg/L as Cl2) and CuSO4 (from 3 to 5 mg/L as Cu), it was found to be an excellent supplementary process because less than 1000 CFU/100 mL were recorded and this value satisfies the international recommendations. The treatment as a whole showed removal efficiencies of 45% as COD, 73% SST, 99% helminth eggs, 99.99% faecal coliforms and from 7 to 87% in heavy metals.
Biological nutrient removal at a very low-loaded activated sludge plant with high biomass concentrations
Authors: Kiuru H. J. , Rautiainen J. A. 
Published: May 2018

The Laboratory of Environmental Engineering at the Helsinki University of Technology (HUT) carried out in 1991-1995 two successive full-scale research and development projects at the Pihlajaniemi WWTP of Savonlinna concerning biological nutrient removal from municipal wastewater. The projects have resulted in two reports in Finnish with quite large English summaries.
This WWTP was constructed originally (1978) as a conventional low-loaded activated sludge plant with the simultaneous precipitation of phosphorus. It was dimensioned for a sludge concentration of 3.5 kgMLSS/m3 in the aeration tanks. Six years later (1984) the plant was fitted with a tertiary stage of flotation filters in order to improve the removal of suspended solids and phosphorus. Nitrification was introduced to the activated sludge process of the plant in 1987. It could be done without any extension by using the sludge concentrations of 6-10 kgMLSS/m3 in the aeration tanks. In that way, this activated sludge process was converted into a very low-loaded one. The process became able to nitrify totally in the circumstances in which the wastewater temperature varies at the range of 4-20°C. The actual hydraulic as well as the BOD7-load of the plant are about 40% of the original dimensioned ones.
This activated sludge process of the Pihlajaniemi WWTP was modified in 1991-1993 for nitrogen removal and then in 1994-1995 for both biological phosphorus and nitrogen removal Denitrification was introduced to the process and the simultaneous precipitation of phosphorus in that was replaced by biological phosphorus removal still without any extension of the activated sludge process. The plant has now been operated over four years with biological nutrient removal exploiting the organic carbon compounds of the wastewater. A very little addition of some precipitant is used to improve the biological removal of phosphorus. The chemical and energy cost of the plant has been reduced by some 50% due to the introduction of biological nutrient removal.
The BOD7-value of the treated wastewater is mainly less than 3 mg/l (always less than 5 mg/l). The content of total phosphorus in the treated wastewater is usually less than 0.3 mg/l (always less than 0.5 mg/l). The content of total nitrogen in the treated wastewater is mainly 8-12 mg/l. Reductions for BOD7 and total phosphorus over 95% as well as that for total nitrogen about 70% are achieved.
A computational fluid dynamics (CFD) particle tracking approach to efficiency prediction
Authors: Stovin Virginia R. , Saul Adrian J. 
Published: May 2018

Storage chambers play an important role in urban pollution management. They are frequently used in conjunction with CSO structures, where they reduce the number and magnitude of CSO spill events. However, one problem associated with the use of storage tanks at CSOs is the deposition of sediment. Techniques which enable engineers to design such chambers for minimal deposition are required.
In this paper the use of the particle tracking routine contained within the Fluent computational fluid dynamics (CFD) software for the prediction of sediment deposition in storage chambers is described. The paper details the way in which the particle tracking routine was configured to produce realistic efficiency results for the comparison of storage chamber performance. Consideration was given to the physical characteristics of the sediment, the injection location, the boundary conditions and a number of relevant simulation parameters. The sensitivity of efficiency prediction to the selection of these parameters is emphasised. The paper also demonstrates the potential application of particle tracking to the prediction of probable deposit locations.
Performance of a subsurface constructed wetland in Iran
Authors: Badkoubi A. , Ganjidoust H. , Ghaderi A. , Rajabi A. 
Published: May 2018

The high capital, operational and maintenance costs of municipal wastewater treatment plants in Iran are a concern for the government. Wastewater treatments in natural systems have shown suitable methods for their low cost. The performance of a pilot-scale subsurface constructed wetland with Phragmites australis to treat municipal wastewater has been investigated. The purpose of this study was to determine the surface area requirement per person in an arid region to achieve an acceptable quality in terms of discharge standards.
Experiments were carried out in two cells (15 × 10 mxm) with media size ranging from 4-8 mm. One cell was used as blank (unplanted) and the other one was planted. Different hydraulic loading rates ranging from 5 to 20 L/min were used. Minimum land requirement was determined to be 1-2 m2/P.E. to reduce COD (86±4%), BOD5 (90±3%), TSS (89±4%), TN (34±6%), TP (56±5%) and fecal coliform (&gt;99%).
The experience of using a decision support system for nutrient management in Australia
Authors: Davis J. Richard , Farley Trevor F. N. , Young William J. , Cuddy Susan M. 
Published: May 2018

Australia experienced an outbreak of algal blooms in the early 1990s that led to a concerted national program to reduce eutrophication. Most Australian States drew up nutrient management strategies which required catchment management groups to produce plans for nutrient reduction within their catchments. Most catchment management groups used the Catchment Management Support System (CMSS) to assist them in the preparation of these plans. CMSS is a simple decision support system developed by CSIRO (the national research organisation) which allows managers to assess the effects of Land Use and Land Management policies on nutrient loads. CMSS has been widely adopted by managers and community groups throughout eastern Australia and has been instrumental in drawing up many nutrient management plans. The program's success is attributed to its design features such as its simplicity of use, very low data demand, suitability for the specific institution task and the degree of documentation, training and support offered.
In this paper the application of CMSS to the Hawkesbury-Nepean Catchment in New South Wales is used to illustrate features of the decision support system, and its relevance to policy formulation.
Water quality considerations in developing a new resource for water supply within the midlands of England
Authors: Smith D. J. , Crymble S. 
Published: May 2018

Increasing demand for limited water resources within the Midlands of England resulted in a lower quality river being considered for water supply in an area of high urban and rural population. A comprehensive water quality monitoring programme was undertaken on the river to compare its quality with other sources used for water supply. Concurrent with the monitoring programme a series of laboratory scale trials began to assess how the river water could be treated, and the costs involved. A major consideration was the need to provide treated water by the summer of 1997, which precluded a complete new water treatment process from being designed.
The paper outlines the results from the monitoring programme, including some of the problem parameters such as pesticides at over 10 ug/l, and how some of the sources of these pollutants were identified. It also describes the treatment trials and explains how a water treatment process was developed which utilises disused gravel workings to provide bankside storage and a combination of powdered and granular activated carbon to remove organic pollutants.
Heavy metals in rivers and soils of central Chile
Authors: Schalscha B. Eduardo , Ahumada T. Ines 
Published: May 2018

Industrial and domestic waste waters in Chile are discharged without previous treatment into rivers and other inland waters which are used to irrigate agricultural lands. The present study reports on results obtained when analyzing inland waters for Cd, Cu, Zn, Hg and As. Copper content was found to be high in most of the rivers studied and its sources were identifiable copper mining wastewaters. Cadmium and Zn levels are above accepted levels in some instances, whereas Hg and As content of river waters under study studied were found to be within accepted levels.
The more reactive chemical forms of heavy metals in soils irrigated with polluted waters, as determined by sequential extraction, were found to be the most abundant ones. These forms are easily bio-available.
Upgrading for nitrogen removal, using a combination of SBR (sequencing batch reactor) technique and unloading of existing biological stage
Authors: Rosén Björn , Ullman Anders , Ragnarsson Nils 
Published: May 2018

Many waste water treatment plants in Sweden have been using pre-precipitation, which has considerably decreased the load on the existing activated sludge process. In many cases it has been possible to introduce predenitrification, with minor changes or increase of volume, in order to reach the required effluent values, which in Sweden varies between 10 and 15 mg Ntot/l as annual average value.
In treatment plants with anaerobic digestion of sludge, some 15–20% of the nitrogen load is recirculated with the return liquors from dewatering. Separate treatment of ammonia-rich return liquors has successfully been using SBR-technique for nitrogen removal, adding external carbon source, e.g. methanol or ethanol. The overall result is, however, not sufficient to meet the requirement, without additional action.
The use of SBR-reactors, designed for nitrification/denitrification of return liquors from dewatering of digested sludge, and part of the influent raw waste water, 20–30%, as a carbon source, has been proven most cost-effective, both from investment and operation cost point of view. The result is a considerably decreased load on the existing biological stage, making it possible to introduce pre-denitrification without any extension of reaction volumes. The paper presents the result from full-scale operation of some plants in Sweden.
The use of immersed membranes for upgrading wastewater treatment plants
Authors: Buisson H. , Cote P. , Praderie M. , Paillard H. 
Published: May 2018

Membranes can be installed in the clarifier (or aeration tank) of an existing activated sludge plant to enhance the biomass separation function of the system, thereby effectively overcoming any operating constraints associated with sludge settleability. The resulting upgraded plant can be operated at high biomass concentrations (10–20 gMLSS/L), leading to an increase in its treatment capacity. The membranes also ensure a treated water consistently free of suspended solids and a superior disinfection performance. The system offers an enhanced operating flexibility, and allows to operate at high sludge ages leading to a low excess sludge production.
Such an immersed membrane activated sludge process (BIOSEP®) has been developed and applied to the treatment of raw sewage. When treating screened raw sewage with this process, with a sludge concentration of 15 gMLSS/L and a volumetric loading of 1.2 kgCOD/m3/d, a 96% COD reduction and a 95% Total Kjeldahl Nitrogen (TKN) reduction have been obtained. The disinfection performance of the system was over 6 Log removal for fecal coliforms. The resulting production of sludge was 0.20 kgMLSS/kgCOD.
Two desk case studies are given for 900 m3/day upgraded plants. In one case, the primary objective was to increase the treatment efficiency and develop nutrient removal for the original plant, while in the other case the primary objective was to increase the capacity of the original 460 m3/day plant.
The role of physical-chemical treatment in wastewater reclamation and reuse
Authors: Adin Avner , Asano Takashi 
Published: May 2018

Amid the heightened public health concerns for emerging microorganisms such as cryptosporidium and enteropathogenic E. coli in the water environment, there have been many instances where optimization of chemical coagulation-flocculation processes and filtration of wastewater was not achieved in practice, resulting in waste of coagulant chemicals and breach of the multiple barriers to pathogen removal and inactivation; thus, unnecessarily endangering public health. In addition, lack of information on the optimization of these processes has hampered the establishment of alternative and more cost-effective wastewater reclamation methods for tertiary and advanced wastewater treatment.
Thus, the purpose of this paper is to evaluate the basic factors affecting the optimization of chemical coagulation-flocculation and filtration processes in municipal wastewater reclamation and reuse, based on the theoretical developments and practical applications. Reference is also made to the wastewater treatment processes and operations that can produce reclaimed water with an extremely small probability of enteric virus contamination.
Point and diffuse load of nutrients to the Baltic Sea by river basins of North East Germany (Mecklenburg-Vorpommern)
Authors: Behrendt H. , Bachor A. 
Published: May 2018

The results of a study on the riverine nutrient emissions and loads of nine river basins of the country Mecklenburg-Vorpommern to the Baltic Sea are presented for the period 1992 to 1994. The basins represent about 76% of the Baltic Sea catchment area of Mecklenburg-Vorpommern. The population living in the basins causes point emissions of 1752 tN/a and 293 tP/a. The analysis of diffuse emissions of nutrients is based on digitized maps of the land use and the soil types, the livestock numbers in the basins and measurements on the nutrient concentrations in the groundwater and drainage areas. The used method considers different pathways of diffuse sources as load from urban areas, erosion, load by groundwater, and drainage systems, atmospheric deposition, and direct load by agricultural activities. The dominant pathway of nitrogen emissions is the emissions of drainage. For phosphorus the emissions by erosion, groundwater and drainage are the main sources. The emissions of point sources contribute to the total emissions to 10% (N) and 25% (P), respectively. The measured nutrient load at the monitoring stations of the rivers is in all cases lower than the sum of the nutrient emissions. This behaviour can be explained by intensive retention processes in the rivers, which depends on the specific runoff, and for nitrogen additionally on the area of surface water in the basin.
Measures against the high nutrient load have to be focussed on the reduction of diffuse sources, especially the emissions of nitrogen and phosphorus by drainage systems have to be reduced, and additionally in the case of phosphorus the emissions by erosion and by direct agricultural load.
Use of variable orifice “duckbill” valves for hydraulic and dilution optimization of multiport diffusers
Authors: Duer Michael J. 
Published: May 2018

The use of variable orifice “duckbill” valves hydraulically optimizes marine effluent diffusers by generating higher jet velocity at low flows, reduced headloss at peak flow, and a more uniform port discharge distribution. Recent laboratory experiments showed that near field mixing and dilution were substantially improved with duckbill valves, and the purging of salt water from an outfall occurs at much lower flow than the theoretical flow required to purge a conventional outfall. An inherent characteristic of the duckbill valve is that it is a check valve that prevents the ingress of salt water, sediment, and marine organisms into the outfall during periods of low flow and hydraulic transients.
This paper presents the hydraulic advantages of variable orifice duckbills verses fixed orifices with emphasis on enhancements in initial dilution and minimization of headloss at peak flow. The process of salt water purging will also be presented along with a brief discussion on failure mechanisms of conventional diffusers.