bluuebunny/crossref_metadata_2025_split huggingface dataset:
Upgrading of wastewater treatment plants to achieve advanced standards concerning nutrient removal
Authors: Buß S. , Einfeldt J. , Günter H. , Werner T. 
Published: May 2018

According to the general wastewater administration rule, it is allowed for the single state authorities of Germany to make the minimal requirements on quality of wastewater discharge more restrictive then those given by the federal government. Schleswig-Holstein particularly has made extensive use of this rule in the past years. On addition of fluctuations due to tourism, industry or combined sewer system, the general criteria for the layout of wastewater treatment plants (WWTP) are presently unsatisfactory in order to meet these requirements. More detailed and comprehensive studies need to be carried out to fulfill these stricter demands.
By illustrating four case studies of WWTP designs of size between 43,000 and 640,000 total number of inhabitants and population equivalents (PT), possible solutions will be presented. With the aid of land-registers, intensive measurement series and semi-technical and full scale experiments, design concepts including multi-stage and split flow treatment could be established.
A novel high rate method for the nitrification of sludge liquors containing high levels of ammonia
Authors: Pickin S. R. , Saunders F. J. 
Published: May 2018

A high rate nitrification system is proposed for the nitrification of digested sludge liquors with N-NH3 levels of between 500 and 1,000 mg/l.
Bench and pilot scale studies have established that loading rates of between 1.0 and 2.0 kg N-NH3/m3 of reactor volume/day are achievable by maintaining a constant 30° C reactor temperature. The effluent standard was set at 40 mg/l of N-NH3.
Loading rates in excess of 1.0 kg N-NH3/m3 of reactor volume/day required supplementing conventional fine bubble diffusion with pure oxygen.
pH and alkalinity control were utilised to maintain the pH in the range 7.2 – 7.6 and total alkalinity in excess of 250 mg/l (as CaCO3) by the use of a feed mixture of NaOH and NaCO3 (20 and 40 g/l respectively).
The nitrifying population was fixed and stabilised within the reactor by using reticulated foam blocks (25 mm × 25 mm s× 25 mm) occupying approximately 30% of the reactor volume.
Settlement was achieved by conventional clarification with a nominal up flow velocity of 1.0 m/hour.
A Novel Method for Biological Treatment of Bleached Kraft Mill Wastewaters
Authors: Strehler Andrew , Welander Thomas 
Published: May 2018

Removal of adsorbable organic halogen (AOX) and chemical oxygen demand (COD) from bleached kraft mill effluent was investigated in laboratory and pilot scale aerobic suspended carrier reactors and abiotic thermo-alkaline reactors.
Laboratory treatment focused on determination of loading capacity of the suspended carrier process and operation of the process at elevated temperature and pH values in order to combine abiotic thermo-alkaline dechlorination and biological treatment in one reactor. At pH 7, 37°C and hydraulic retention times (HRTs) longer than 3.5 hours, a maximum COD removal of 55% was achieved in the suspended carrier process. The COD conversion rate at the minimum HRT was 2.6 kg COD/(m3*d). The suspended carrier treatment was operated successfully at pH 9.0 and 45°C and at pH 7.0 and 50°C with over 50 percent COD removal with a HRT of four hours. The AOX removal achieved at pH 9 and 45°C (50%) was significantly higher than the removal at pH 7 and 37°C (39%), most certainly because of an increased abiotic dechlorination at the higher pH and temperature levels.
Sequential thermo-alkaline and biological treatment were studied on a pilot scale. Tbermo-alkaline treatment at pH 10, 54°C and a HRT of two hours followed by biological treatment at pH 8, 35°C and a HRT of four hours, removed almost 80% of AOX and 50% of COD from the kraft mill effluent.
Biological Removal of Chlorate from Bleaching Plant Effluent
Authors: Malmqvist Åsa , Welander Thomas 
Published: May 2018

Biological chlorate removal was studied on a laboratory and a pilot scale with the aim of optimizing process design and operating conditions with respect to process efficiency, stability and economy.
The results showed a suspended-carrier biofilm process design to be suitable for biological chlorate removal. In the laboratory tests, at pH 7 and 37°C, a complete removal of chlorate could be maintained at hydraulic retention times (HRTs) as short as 24 min. A longer HRT (1.5 h) was required for complete chlorate removal in the pilot test, due to a lower degree of filling with carrier material (25% versus 50% of the reactor volume), higher process temperature, and leakage of oxygen into the process. However, it is assumed that the loading capacity of a large-scale process would approach that of the laboratory system if the operating conditions were the same.
Laboratory tests showed chlorate reduction to be possible within a wide range of pH values and temperatures, although the process stability and loading capacity were strongly affected by changes in these parameters.
The results of the laboratory and pilot scale studies, using a suspended-carrier process design, show biological treatment to be an economically viable and efficient process for the removal of chlorate from bleaching plant effluents.
Feasibility of Anaerobic Pre-Treatment for the Effluents from Hardboard and Laminated Board Industry
Authors: Eroglu V. , Oztürk I. , Ubay G. , Demir I. , Korkurt E. N. 
Published: May 2018

This paper presents results of a comparative evaluation of the feasibility of anaerobic pre-treatment for the effluents from a hardboard and laminated board industry.
The problems associated with the treatment of hardboard mill wastewaters using activated sludge process have been observed as relatively low COD removal, high energy cost and high amounts of excess biological sludge production. The purpose of the study is to evaluate the effectiveness and feasibility of the anaerobic pre-treatment to reduce the excess biological sludge production and energy consumption in the aerobic stage. Anaerobic treatability studies were carried out by a lab-scale upflow anaerobic sludge blanket reactor (UASBR) with an effective volume of 10 litres. The UASBR was operated for a wide range of organic and hydraulic loadings during the experimental studies of more than 4 months. Anaerobic treatability studies have shown that a COD removal of 60% is possible at organic loading rates of 5-11 kg COD/m3.d. Anaerobic treatability study results have shown that 70 percent reduction both in the excess sludge production and in energy for aeration are possible by applying anaerobic pre-treatment. Considering these findings, it was demonstrated that anaerobic pre-treatment is a feasible option for waste management of the hardboard mill effluents.
The treatment trilogy of floating filters: from pilot to prototype to plant
Authors: Toettrup H. , Rogalla F. , Vidal A. , Harremoes P. 
Published: May 2018

The basic kinetic expressions developed in non-aerated biofilms (denitrification and RBCs) were verified on granular floating media in aerated filters. The limiting parameters of biofilms were verified on a small scale lab unit, using wastewater and media from full scale. It could be shown that the observed relationships corresponded to theoretical expectations and half-order kinetics as well as the significant constants were established. Maximum surface removal rates were measured as 1.7 g N-NH4/m2 d for nitrification, and the most limiting parameter was a half-order oxygen concentration close to saturation.
Similar kinetics as on small scale were observed on a full-scale prototype of a new floating aerated biofilter, which can be used for both nitrification and denitrification, as well as complete nitrogen removal from settled wastewater in one reactor. The mixed biofilm nitrified 15 % less than pure tertiary treatment, and 20 % performance was lost between lab and full scale, due mainly to aeration limitations. Also, 35 % lower denitrification rates were observed between ethanol and sewage as carbon source, but addition of ethanol raised the full-scale performance to nitrate removal rates of 1,4 g N-NO3/m2 d.
After pilot testing and full-scale demonstration, the process was implemented on several treatment plants, one of which was located in Denmark, to achieve nitrogen residuals below 8 mg TN/1. This plant uses 8 filters of 63 m2 to treat 12 000 m3/d, and the biological reactor occupies a surface similar to the existing conventional primary settler. The results of the first few months of operation are given: as long as the ratio between biodegradable COD and total nitrogen at the filter inlet is above 5, nitrogen removal of 80 % is achieved.
Optimisation of retention basin decanting
Authors: Bourgogne Pierre , Chorda Jacques 
Published: May 2018

The cleaning of rainwater is a big challenge for the coming years. Numerous experiments are undertaken, especially in the field of elutriation. The option of decanting gives the most interesting results in the elimination of this particular kind of pollution.
By contributing to such research activity, the Bordeaux Urban Community Council wishes to develop a new type of settling basin, enabling an efficient decanting process, a good removal of pollution, as well as easy maintenance, without having to use sophisticated equipment.
Bacterial die-away rates in red sea waters
Authors: Sarikaya H. Z. , Saatçi A. M. 
Published: May 2018

Total coliform bacteria have been chosen as the indicator organism. Coliform die-away experiments have been carried out in unpolluted sea water samples collected at about 100 m off the coastline and under controlled environmental conditions. The samples were transformed into one litre clean glass beakers which were kept at constant temperature and were exposed to the solar radiation. The membrane filter technique was used for the coliform analysis. The temperature ranged from 20 to 40° C and the dilution ratios ranged from 1/50 to 1/200.
Coliform decay rate in the light has been expressed as the summation of the coliform decay rate in the dark and the decay rate due to solar radiation. The solar radiation required for 90 percent coliform removal has been found to range from 17 cal/cm2 to 40 cal/cm2 within the temperature range of 25 to 30° C. Applying the linear regression analysis two different equations have been given for the high (I&gt;10 cal/cm2.hour) and low solar intensity ranges in order to determine the coliform decay rate constant as a function of the solar intensity.
T-90 values in the light have been found to follow log-normal distribution with a median T-90 value of 32 minutes. The corresponding T-90 values in the dark were found to be 70-80 times longer. Coliform decay rate in the dark has been correlated with the temperature.
Problems related to an existing marine outfall: Marmaris - an example
Authors: Samsunlu A. , Akça L. , Uslu O. 
Published: May 2018

Marmaris is a tourist city on the South-west Coast of Turkey. A sewage disposal project for Marmaris with an estimated population of 39,000 (excluding the temporary tourist population) for the year 2012, was completed in 1982. The sewage disposal system consisted of wastewater collection, treatment and deep sea discharge. The length of discharge pipe was determined as 520 m and a diffuser was placed 20 m below the sea level, so that the total coliform concentration at the protection zone boundary could be less than 1000/100 ml.
Following the approval of the project, a wastewater collection and marine disposal system was constructed. The material of the discharge pipe was selected as glass reinforced plastic (GRP). The pipe was buried up to a point 10 m below sea level, so that effects of hydrodynamic forces would be minimized. After that point, the pipe was supported at some location by grout bags due to the uneven sea bed. A few years later, it was recognized that the discharge pipe was broken. The fragile GRP material had fractured as a result of the sliding of some of the supports with resultant free spanning conditions. As a result, the pipe had broken at one point. Although the breakage was repaired, recent data have shown that the water quality in Marmaris Bay has a tendency to be worsening; consequently, adding biological treatment units to the present system is advisable.
Monitoring of sewage outfalls in northern spain: preliminary studies of benthic communities
Authors: Juanes José A. , Canteras Juan C. 
Published: May 2018

Baseline studies constitute, at the same time, the base and the reference point for the development of site-specific monitoring programs. As a previous step in the analysis of the structure of benthic communities in the infralitoral off Avilés and Gijón, multivariate techniques were used to assess the agreement between the distribution pattern of samples, from both rocky and soft bottom benthos, according to their species or family compositions.
Sampling was carried out in summer 1992. Stations were located on a depth gradient basis (A: −1 m; B: −5 m; C: −15 m; D: −25 m; E: −35 m; F: −45 m) along eight transect lines. Abundance data from replicate samples from each station, aggregated at both the species and the family levels, were tested by three complementary multivariate measures of community structure: clustering (CL), principal components analyses (PCA) and multidimensional scaling (MDS) techniques.
The main results obtained in this study demonstrated the adequacy of family-based abundance data for carrying out classification and ordination of samples from both rocky and soft bottom benthic ecosystems.
Dilution studies on three marine outfalls in South Africa
Authors: Botes Willem A. M. , Kapp J. F. 
Published: May 2018

Field dilution studies were conducted on three “deep” water marine outfalls located along the South African coast to establish the comparibility of actual achievable initial dilutions against the theoretical predicted values and, where appropriate, to make recommendations regarding the applicability of the different prediction techniques in the design of future outfalls.
The physical processes along the 3000 km long coastline of South Africa are diverse, ranging from dynamic sub-tropical waters on the east coast to cold, stratified stagnant conditions on the west coast. Fourteen existing offshore marine outfalls serve medium to large industries and various local authorities (domestic effluent). For this investigation three outfalls were selected to represent the range of outfall types as well as the diversity of the physical conditions of the South African coastline.
The predicted dilutions, using various approaches, compared well with the measured dilutions. It was found that the application of more “simple” prediction techniques (using average current velocities and ambient densities) may be more practical, ensuring a conservative approach, in pre-feasibility studies, compared to the more detailed prediction models, which uses accurate field data (stratification and current profiles), when extensive field data is not readily available.
Enhancement of biomass concentration in activated sludge systems
Authors: Plaβ R. , Sekoulov I. 
Published: May 2018

By installation of lamella in the activated sludge tank an increase of biomass concentration in the activated sludge tank can be achieved without additional charge of the secondary clarifier. Integrated packages of lamella which are installed in the discharge of the activated sludge tank at an angle of 60° effect a partial sedimentation and so a MLSS-preseparation.
The MLSS in the activated sludge tank (influent of the lamella construction) was 6.5 g/l, the MLSS in the influent to the final clarifier (effluent of the lamella) was 3.1 g/l. That means that the lamella increased the MLSS concentration in the activated sludge tank by a factor of two. Despite a volume loading of 1.24 kg BOD5/(kg MLSS • d) a complete nitrification could be obtained. For ensuring a stable process and a balanced concentration of the biomass in the influent of the secondary clarifier, the preseparation of solids in the lamella is controlled by addition of air bubbles.
By the enhancement of biomass concentration using this preseparation device, the extension of waste water treatment plants can be carried out with lower investment costs.
Ecological restoration of the Rhine/Maas estuary
Authors: Kuijpers J. W. M. 
Published: May 2018

In 1995 it will be 25 years since the estuary of the Rhine and Maas was closed off from the sea by a dam with outlet sluices. After 1970 it gradually became clear that the change of an open estuary into a semi-stagnant lake had many negative ecological effects: bank erosion, accumulation of polluted sediments and the disappearance of a natural transition zone between the estuary and the sea. As the public attention to nature conservation in The Netherlands grew over the years, this ecological degradation was more and more recognized as a problem.
To achieve a healthier ecosystem a program of remedial action has been launched. Some elements such as the protection of valuable wetlands against erosion have almost completely been realised. Others such as the removal of large quantities of polluted sediment and a change in the operating program of the outlet sluices are being prepared. The main challenge is to find a compromise between ecological values and all kinds of human use of the water system.
Eutrophication and ecological rehabilitation of Dutch lakes: Presentation of a new conceptual framework
Authors: Klinge M. , Grimm M. P. , Hosper S. H. 
Published: May 2018

Lake restoration is a major issue in water management in The Netherlands. In this context biomanipulation is considered an important tool following the reduction of the nutrient load. Here we present a new conceptual framework and try to quantify the productivity level below which predator control of the fish population, which is considered a prerequisite for successful biomanipulation, occurs.
The conceptual framework focuses on a balance between preyfish production and piscivorous fish consumption. When the piscivorous fish consumption (top-down control) is too low to control the preyfish community (bottom-up forces), the abundance of small planktivorous fishes will increase, leading to the cascading effects of a heavy predation on zooplankton and an excessive development of algae resulting in an increase of turbidity. With the framework the total-P concentrations characterising lake productivity at such turning points can be calculated.
The framework is used to explain the eutrophication process of Dutch lakes, which is described as a series of stages between which shifts in community structure including the dominant piscivorous fish species occurred. Furthermore, based on the framework some predictions and methods for ecological rehabilitation will be presented.
Policy analysis and complexity – a non-equilibrium approach for integrated water management
Authors: Geldof Govert D. 
Published: May 2018

In integrated water management, the issues are often complex by nature, they are capable of subjective interpretation, are difficult to express in standards and exhibit many uncertainties.
For such issues, an equilibrium approach is not appropriate. A non-equilibrium approach has to be applied. This implies that the processes to which the integrated issue pertains, are regarded as “alive”’. Instead of applying a control system as the model for tackling the issue, a network is used as the model. In this network, several “agents”’ are involved in the modification, revision and rearrangement of structures. It is therefore an on-going renewal process (perpetual novelty).
In the planning process for the development of a groundwater policy for the municipality of Amsterdam, a non-equilibrium approach was adopted. In order to do justice to the integrated character of groundwater management, an approach was taken, containing the following features: (1) working from global to detailed, (2) taking account of the history of the system, (3) giving attention to communication, (4) building flexibility into the establishing of standards, and (5) combining reason and emotions.
A middle course was sought, between static, rigid but reliable on the one hand; dynamic, flexible but vague on the other hand.
A multi-disciplinary Danish research programme on rainbow trout (Oncorhynchus mykiss) farming
Authors: Berg P. , Eggum B. O. , Møller S. H. , Holm L.-E. , Jørgensen P. E. V. , Olesen N. J. , Buchmann K. , Larsen J. L. , Dalsgaard I. , Mellergaard S. , From J. , Frier J.-O. , McLean E. , Hørlyck V. , Graver C. , Kristensen T. P. , Birk E. , Bovbjerg P. 
Published: May 2018

A new research programme involving eight Danish institutions is described. The programme started in 1993 and is expected to run for 5 years. The primary objective of the research initiative is to exploit and integrate the knowledge of several institutions and disciplines for the benefit of the production of rainbow trout. The programme includes several projects with aspects of disease prevention, genetics, and nutrition. In most of the projects, the work has been divided into stages of 2 and 3 years, respectively. During a 2 year period, production, management, and health status are recorded at the participating fish farms, and all data are organized in a database. Diseases cause major problems in rainbow trout production, therefore a great deal of the effort in this programme deals with diseases caused by vira, bacteria and parasites. On the basis of the database, epidemiological examinations are carried out as well as investigations of the possibilities of preventive measures and cost-benefit analyses.
In the genetic studies, polymorphic genetic markers will be developed and used for analysis of the genetic structure of selected fish stocks. Microsatellites will be developed and introduced in the study. Primarily genetic differences between lines/strains and their crossings will be estimated with the purpose of describing the genetic level and the importance of additive and non-additive genetic effects. In the nutritional area the product quality and pollution questions will be in focus.
Wastewater characteristics in Palestine
Authors: Nashashibi M. , van Duijl L. A. 
Published: May 2018

Wastewater treatment plants in Palestine (West Bank and Gaza Strip) have been designed upon assumptions of wastewater characteristics and amount of flow, because no data were available at all. This study is focused on the collection and measurement of wastewater quantity and quality, which will be used as a basis for formulating a strategic plan for wastewater treatment in Palestine. In view of the limited water resources, reclaimed wastewater will be used for agriculture, which, at present, is done at a very limited scale.
The infrastructure in Palestine used to be a neglected issue, particularly with regard to sewerage. Blocked pipes and flooded manholes are daily events especially in Gaza Strip. All existing treatment plants are heavily overloaded. Groundwater resources in Gaza Strip become more and more polluted with nitrate concentrations exceeding 100 mg NO3-N/l resulting from seepage from cesspits and effluent discharges into wadis.
Due to scarcity of water, domestic water consumption is very low, which leads to highly concentrated wastewater similar to industrial one. In one city in the West Bank, the COD reached a value of 3,670 mg/l, although all the water reaching the outfall is of domestic type.