bluuebunny/crossref_metadata_2025_split huggingface dataset:
Upgrading a Large Municipal Sewage Treatment Plant by a Combination of Biological and Chemical Processes
Authors: Hahn H. H. , Hoffmann E. , Kleinschmidt A. , Klute R. 
Published: May 2018

The Standards controlling sewage treatment are continuously in development. Thus, upgrading existing plants is a frequently encountered problem. In the past this meant structural changes, mostly in terms of enlargement of existing facilities or addition of new units. More recently the possibilities of improving plant performance through chemicals addition (inducing precipitation and coagulation) with or without intensified biological treatment have been explored. Chemicals addition has become necessary in many instances due to the tightening of standards for phosphorous concentrations in the plant effluent.
The present discussion is based on a case study where possibilities and limits of chemical and/or biological upgrading have been investigated. The analysis showed that neither chemical stages nor secondary biological stages alone can guarantee the effluent standards formulated by the water authorities.
Nitrification and Denitrification in Combined Activated Sludge Systems
Authors: Wartchow D. 
Published: May 2018

Various investigations into batch reactors as well as into continous flow activated sludge plants in laboratory and pilot scale had the aim to determine the difference of the nitrification and denitrification capacity of fixed and suspended biomass in combined systems. By adding porous support material a certain amount of biomass is fixed on this material in a conventional aeration basin of an activated sludge plant. The dimensioning of activated sludge plants for nitrification considers the sludge age of the activated sludge. With fixing the biomass on the support material in the aeration basin, the sludge age can be raised without increasing the MLSS and therefore without increasing the loading of the secondary clarifier.
Measurements of the oxygen consumption of the suspended sludge and the fixed sludge in situ, e.g. without removing the biomass from the support material, as well as the nitrogen balances showed that the nitrification capacity of the fixed biomass is about 20-30 % less than that of the suspended biomass, related to the organic dry matter (MLSS). Also the fixed sludge had a lower organic dry matter than the suspended sludge. This led to the conclusion that there is no linear dependency between increasing the biomass in the aeration basin by adding support material and the nitrification capacity of the whole sludge mass. Regarding the denitrification the measurements showed that a simultaneous denitrification takes place inside the support material although the oxygen concentration in the liquid phase is between 2-4 mg/l.
The denitrification is caused by a lack of oxygen in the deeper regions of the biofilm. This can also be a reason for the observed lower nitrification capacity of the fixed sludge. However, the combination of fixed biomass on porous support material and suspended biomass has the advantage of increasing the total biomass in the system. Furthermore under certain circumstances a simultaneous denitrification takes place in the totally aerated basin. The measurement itself and the findings of the investigations will be presented and discussed in detail in the paper.
Wastewater Treatment by Soil Absorption Systems
Authors: Ebers T. , Bischofsberger W. 
Published: May 2018

In the Federal Republic of Germany, the barely treated wastewater of about 7 million people is percolated into the soil. Groundwater quality has now become a major concern, and investigations into soil filtration as a means of eliminating pollution from household wastewater have been started. Experiments with six laboratory lysimeters (diameter = 0.4 m, height = 1.8 m) are described. Three lysimeters were filled with slightly silty sand, the other three with fine gravel sand. All lysimeters have been in operation for about two years. Initially they were loaded with mechanically treated wastewater from a municipal treatment plant and later with effluent from a septic tank. Hydraulic loading varied from 0.5 to 31 cm/d. Results showed good efficiency for fine gravel sand (aerobic conditions) in removal of BOD5 (98.0 to 99.2 %), COD (88.0 to 92.8 %) and Kjeldahl nitrogen (90.0 to 91.3 %). Elimination of phosphate ranged from 5.7 to 86.0 %. Slightly silty sand (anaerobic conditions) showed the best results in elimination of phosphate (86.0 to 99.3 %) and relatively good elimination rates were achieved for BOD5 (65.0 to 98.2 %) and COD (about 76 %). Elimination of Kjeldahl nitrogen ranged from 39.6 to 68.4 %.
The results for the two soils can be summarized as follows:
Fine gravel sand: high hydraulic loading capacity (aerobic conditions); high elimination rates of BOD5 and COD; high elimination rates of ammonium by nitrification; very low elimination of total phosphate.
Slightly silty sand: low hydraulic loading capacity and, despite this, anaerobic conditions; high elimination rates of BOD5 and barely inferior elimination rates of COD in comparison to fine gravel sand; low elimination rates of ammonium; very high elimination rates of total phosphate.
Urban Storm Water Discharges: Effects upon Communities of Sessile Diatoms and Macro-Invertebrates
Authors: Willemsen G. D. , Gast H. F. , Franken R. O. G. , Cuppen J. G. M. 
Published: May 2018

From 1985 to 1987, long-term and more or less permanent effects of discharges from combined or separate sewer systems on communities of sessile diatoms and macro-invertebrates in receiving waters have been studied. Sessile diatoms and/or macro-invertebrates have been investigated on 46 locations, spread all over The Netherlands. The results were related to the type of sewer system, the discharges, and the characteristics of the receiving water, and compared with results from sample(s) taken from a corresponding water not influenced by sewer overflows, the reference water.
In general, communities of sessile diatoms and macro-invertebrates indicate a more severe organic pollution and disturbance of receiving waters compared with reference waters. In the immediate vicinity of the overflows these communities were more disturbed than at some distance. In small ditches, effects were more pronounced compared with large waterbodies and waters with a constant flow regime. Finally, effects of combined sewer overflows were more pronounced than effects of discharges from separate sewer systems, except for locations in industrial areas.
Fylde Coast Bathing Water Improvements – Storm Water Management for Compliance with Bathing Water Directive
Authors: Head P. C. , Crawshaw D. H. , Rasaratnam S. K. 
Published: May 2018

As part of the investigations to determine the most appropriate scheme to bring the Fylde Coast bathing waters up to the quality required by the EC Bathing Water Directive, mathematical models have been used to examine the hydraulic behaviour of the sewerage system and the subsequent dispersion of effluent in the receiving waters. The discharge characteristics of the existing sewerage systems were examined by means of an extensive WASSP model, validated by means of flow measurements gathered from critical points of the sewer network. This model was then used, in conjunction with a time series rainfall record for the area, to investigate the effect of the intensity and duration of rainfall events on the volume of storm sewage to be discharged. Because the area is drained by a combined system, the management of storm water is of utmost importance and the output of the WASSP model was used to determine the input to the coastal dispersion model for rainfall events.
A preliminary examination of the possible sites for sewage treatment works and sea outfalls, for sewage and storm water, suggested four possible schemes involving either inland treatment, marine treatment or a combination of the two. All options required the discharge of storm water to the sea. Extensive dispersion modelling was carried out to examine the probable effects of various storm-water management strategies on bacterial concentrations in the receiving waters. From this it was apparent that storage of storm flows, with controlled discharge, at the state of tide when environmental impact would be minimal, was required to achieve compliance with the provisions of the Directive. By integrating the WASSP modelling of various base-flow and storm-water storage options with dispersion modelling, it was possible to establish appropriate design criteria.
Integrated Water Resources Planning as a Factor in Environmental Pollution Control
Authors: Ngirane-Katashaya Gaddi G. 
Published: May 2018

Integrated water resources planning (IWRP) seeks to rationalize water resources projects in a region for optimum utilization of water, appropriate conservation, cost-effectiveness, and attainment of maximum economic and socio-environmental benefits.
This paper examines those aspects of water resources planning which interact with the environment. It also presents corresponding environmental conservation parameters and various approaches to pollution controls. Mutually pertinent points identify the planning parameters. Case studies of IWRP are presented.
Technical and Economic Analysis of Stabilization Ponds
Authors: Nie Meisheng , Xu Shuimin , Aulenbach Donald B. 
Published: May 2018

Compared with other methods of wastewater treatment, stabilization ponds provide the advantages of low capital cost, low operation and maintenance (O&M) costs and simple manipulations at the expense of a large land area. This study analysed the technical and economic aspects of stabilization ponds in order to determine their recommendation for use in specific location.
Since few stabilization ponds in China were self-designed, and few integrated cost data were available, cost data were determined by a set of series designs. Stabilization ponds are contrasted with activated sludge (AS) system, since AS is a more frequently used method for municipal wastewater treatment. The cost data for AS system were obtained by surveying AS facilities built in China.
The aspects used in this model analysis included (1) capital cost, (2) O&M costs, and (3) occupied land cost. For comparing the total costs of stabilization pond and AS, a new concept, critical land price (Pro), was introduced. Pro is the price of land at which the total cost of a stabilization pond is equal to that of an equivalent AS system. When land price is above the Pro, AS is more economic than a stabilization pond. When land price is below the Pro, a stabilization pond is more economic. In addition to comparing the total costs of AS and stabilization ponds, a comparison was made between stabilization pond in South China and in North China.
The capital cost of a stabilization pond is 1/3 to 1/2 that of an equivalent AS plant, the O&M costs are 1/5 to 1/4 the AS costs, and the occupied land area is 15 to 40 times the AS land area. The Pro decreases with increasing wastewater flow. Using the model analysis, the critical land price in South China (Pros) is in the range of 10,000 to 30,000 RMB/Mo. (Mo. is an area unit used in China, it is equal to 1/15 hectares.) In North China, the critical land price (Pron) is 6,000 to 16,000 RMB/Mo.
Comparing stabilization ponds in the south with those in the north showed that the capital cost, 0&M costs, and occupied land cost in the north are 1.5 to 1.8 times, 1.5 times, and 1.6 to 1.7 times those in the south, respectively.
Choice of Optimal Configurations for Two-Phase Biological Reactors on the Basis of Hydraulic Model Studies of a Wastewater Treatment Plant in Gdańsk
Authors: Maciejewski M. 
Published: May 2018

The paper presents procedure, results and conclusions drawn from laboratory studies of nitrification and denitrification chambers of two-phase biological reactors with recirculation system, for a designed wastewater treatment plant of 270 000 m3/day capacity, for the city of Gdańsk.
On the 1:17 physical model, observations of stream lines and measurements of the velocity field in some characteristic regions have been performed.
The measurements have been carried out for 14 different configurations of the reactor operation, depending on the aerator turbines, mammoth rotors and prototypical mixers with horizontal axle and with guide-ring.
Based on these studies, and having introduced some structural innovations aimed at improving flow uniformity around aerators and rotors, a variant optimal from the point-of-view of hydraulic properties and energy consumption has been proposed for realization.
Moreover, using results of some other investigations performed on a structure in technical scale, conclusions concerning the following questions have been presented:
I/ the importance of uniform velocity distribution in the reactor for final effeot of operation of the wastewater treatment plant,
II/ relationships between velocity, discharge and hydraulic efficiency of the wastewater treatment plant chambers,
III/ the influence of geometry of chambers and of recirculation on the efficiency of the purification process.
The paper includes drawings, figures and short descriptions of the following experimental techniques used in the investigations: the method of varying temperature field, the colorimetric method, the conductometric method and the method using a current micrometer. A video film on the study is available.
On the Manifold Role of Lime Coagulation
Authors: Świderska-Bróż M. 
Published: May 2018

Lime coagulation and 2-hour sedimentation were investigated for their utility in removing humic acids, colour, permanganate COD, and some heavy metals (Cu, Pb, Zn, Ni). Calcium carbonate was found to be responsible for the removal of the majority of the pollutants examined.
Magnesium hydroxide accounted for the further improvement in the removal efficiencies of colour, permanganate COD, humic acids and nickel. This was not so in the case of zinc, lead and copper. Their removal efficiencies decreased when pH reached values higher than 10.5 (which create favourable conditions for the precipitation of magnesium hydroxide). The contribution of magnesium hydroxide to the removal of organice was more pronounced in low-alkalinity solutions with poor precipitation of caloium carbonate.
Lime coagulation produces metal complexes of low solubility, thus providing advantageous conditions for metal-organic co-precipitation (copper and lead were removed together with humic acids).
The results obtained quantified the following finding: lime coagulation which is used in water renovation primarily for the removal of phosphates has an important contribution to the removal of other pollutants (some of them creating health hazards to the population).
Wastewater Treatment and Reuse Aspects of Lake Valencia, Venezuela
Authors: Lansdell Mark , Carbonell Luis M. 
Published: May 2018

The environmental problems of the Lake Valencia Basin are described. A multipurpose project for the treatment and reuse of 9.5 m3/s of wastewater, which has received approval for international funding, is discussed along with technological adaptations to local opportunities and limitations.
The results of bench-scale studies for potable reuse of the Lake's water by softening and blending are also described along with experience of surrogate parameters for Trihalomethane Formation Potential Measurement in a Developing world context.
An Integral Approach to Support Managerial Actions on Micropollutants in the Southern North Sea
Authors: Roos A. , van Vliet J. F. M. , van Pagee J. A. , Nauta T. A. , de Vries M. B. 
Published: May 2018

During the last decades the southern part of the North Sea has been exposed to high inputs of micropollutants from various sources.
Within the framework of the project Management Analysis North Sea (MANS), studies have been carried out to quantify the impact of anthropogenic pollution inputs on coastal water quality, sediments and biota.
In order to study the effects of different managerial actions an integrated modelling framework has been developed to enable a spatial evaluation. In this regard special attention has been given to:–the reduction of river inputs, as a result: of domestic and industrial waste water treatment–the storage of dredging sludge from the Rhine-Meuse estuary.
It is shown by the results of this study that input reductions of heavy metals since 1980 have resulted in a significant reduction of concentrations in Dutch coastal waters. Long-term simulation of accumulation of pollutants in the sediment, however, showed that due to the long time scale the reduction of the seabed can take several decades. Similar conclusions can be drawn for organic micropollutants, although the input reductions seem to be less pronounced.
Based on bioaccumulation modelling, the pollution of the sediment proved to be an important source for uptake of micropollutants in the food web. This study also made clear that significant reductions of North Sea pollution can be established if combined actions are taken. Reduction of pollutants from the Rhine-Meuse estuary, together with the storage of polluted dredging sludge from the Rotterdam harbours, will result in a significant reduction of the state of pollution of the coastal waters of the Netherlands.
The Rotterdam Initiative in Reducing Waste Discharges at Source
Authors: Vellinga T. , Nijssen J. P. J. 
Published: May 2018

Much of the material dredged from the port of Rotterdam is contaminated to such a degree that it must be placed in specially constructed sites. The aim of Rotterdam is to ensure that the dredged material will once again be clean. This will entail the thorough cleansing of the sources of the contamination of the sediment in the harbours and in the River Rhine. The Rotterdam Rhine Research Project (RRP) is one of the means to achieve this based on: technical research, legal research, public relations and dialogues with dischargers.
The programme for five selected heavy metals is almost complete. For many heavy metal discharge points between Rotterdam and Rheinfelden, a specially devised independent load assessment has been carried out four times. Balance studies were used to determine the relative contributions of the point discharges to the total. Currently the results are being used in an attempt to negotiate agreements with a selected number of the major dischargers. At present, more detailed balance studies are being set up and exploratory measurements carried out for organic micropollutants.
It may be concluded that the research is progressing successfully and methods and techniques developed seem satisfactory and broadly applicable. The Rhine Action Programme encompasses an international effort to improve the quality of the Rhine water. Although the RRP plays a modest complementary role to the Rhine Action Plan, there is no doubt of the value of this Rotterdam initiative. The mode of work followed in the RRP contains elements that can be of use in combatting the contamination of the North Sea by rivers other than the Rhine.
Reduced Hydraulic Detention Time for Complete Nutrient Removal with Innovative Biological Reactors
Authors: Rogalla F. , Payraudeau M. , Sauvegrain P. , Sibony J. 
Published: May 2018

To limit pollution discharges through wastewater into surface waters, increasingly stringent effluent standards particularly for nutrient removal require extensive upgrading of conventional wastewater treatment plants. Large sewage treatment plants in Western Europe are often located in densely urbanised areas where land is unavailable. To avoid additional unit processes for nitrogen and phosphorus removal, innovative solutions are demonstrated. A compact reactor is presented that achieves low pollutant residuals (carbonaceous matter, suspended solids, nitrogen and phosphorus) in reduced space and a few examples of full scale applications are given.
Through extensive pilots tests, the limiting parameters for nutrient removal are established on sewage after pretreatment and lamella settling. The biological treatment by two granular filters in series combines biodegradation and suspended solids retention without further particle separation. The anoxic reactor removal rates varied between 0.3 and 1.5 kg N-NO3/m3 d, depending on temperature and available carbon. Nitrification on the aerobic filter increases from 0.3 kg to 1 kg N-NH4/m3 d with temperature in a range between 5 to 20 °C. Total nitrogen residuals below 10 mg/l and effluent phosphorus below 1 mg/l can be achieved with hydraulic retention times of around 3 hours.
Integral Risk Analysis as a Supporting Framework for Water Quality Management
Authors: Bos H. R. , Bowmer C. T. , Scholten M. C. T. 
Published: May 2018

The prevention of pollution in a marine ecosystem such as the North Sea has traditionally been approached from two angles i.e. (1) by controlling the disturbance at source and (2) by monitoring the quality of the marine environment and act when deleterious effects occur. These approaches are loosely based on the precautionary principle and on the concept of assimilative capacity, respectively. Although in principle different approaches, they are similar in practice as they both accept, rightly or wrongly, a certain input of pollutants to the marine environment. There remains however, a stubborn lack of information as to what qualitative and quantitative relationship exists between the input(s)/sources and consequently the distrubance or effects in the marine environment.
Environmental stress in a marine ecosystem becomes visible when the dynamics of its elements deviate from their normal cycles or fluctuations. These observable end-effects are often the initial reason for concern, i.e. long after the process of disturbance is underway. It has always been difficult to interpret these mostly complex signals and relate the observations to primary causes. In order to handle the diversity of information and signals in the cause-effect chain between input(s)/sources and disturbance, the development of a comprehensive logic framework is needed.
Three-Fold Remedial Measures for Groundwater Protection: Case Study of the Khathkari Stream, Pune District, India
Authors: Kalantari Nasrollah , Thigale S. S. 
Published: May 2018

A vast tract in Maharashtra State of India, constituted of horizontally disposed basaltic flows of Cretaceous-Eocene age, falls in the semi-arid climatic zone characterised by low precipitation and high temperature and evaporation. Such areas are marked by the variety of calcretes including massive, honeycomb, nodular, and powdery types. These calcretes which owe their origin to both pedogenic and nonpedogenic processes, are responsible for imparting the salinity to the groundwater.
An integrated approach, involving geological, hydrogeological and hydrochemical studies, has been employed for delineating the boundary of saline and fresh waters in the groundwater system and evaluating the variation in salinity in the area around the Khathkari stream (18 13’ to 18 18’ N latitudes, and 74 13’ to 74 22’E longitudes) in Pune district.
The paper briefly presents the data collected during the course of the work and incorporates the three-fold remedial measures such as i) protecting fresh water that occurs at deeper depth, ii) improving the present quality of water and iii) suggesting an appropriate crop-pattern that can stand for present and improved quality of water.