bluuebunny/crossref_metadata_2025_split huggingface dataset:
New type of sludge density meter using microwaves for application in sewage treatment plants
Authors: Yamaguchi Seiji 
Published: May 2018

Sludge density is an important index for the control of sewage and sludge treatment processes. A new measuring method for sludge density, the microwave phase difference method, has been tested with a good correlation between density and phase difference. Comparison tests with conventional ultrasonic density meters have shown characteristics that are superior to the flow-through type and equivalent to the defoaming type.
We developed a sludge density meter that uses this method and made long-term field tests on the sludge pipelines in sewage treatment plants. Results demonstrated a good correlation with the values that were obtained by manual analysis, with excellent linearity from low density of less than 1% to high density of about 30%.
This new microwave measurement method is less affected by soil build-up and air bubbles, is able to measure a wide range of densities from low to high, and is capable of continuous measurement. It is a highly reliable measuring method for practical applications.
Six years of practical experience with the operation of on-line analysers
Authors: Londong J. , Wachtl P. 
Published: May 2018

The Wupperverband operates 14 sewage treatment plants in the catchment area of the Wupper river.
New treatment plants, which were designed for extended nutrient removal, have been equipped with on-line analysers. To find the lay-out data, to control operation and as a support for the start-up phases of new treatment plants, a mobile container for on-line analysis of COD, BOD, NH4 and NO3 is in use.
Several types of analysers were tested with different types of sewage and at different sampling points (influent, effluent primary sedimentation, effluent denitrification, effluent nitrification and final effluent). This enables us to compare and to assess the tested machines.
As a result of these comparisons and for operational reasons the photometric principle was chosen for further application. Adequate maintenance with trained staff provided, especially of sampling preparation units, all tested photometric analysers could be used for control and automation purposes because of their reliable measuring values.
Strategies for handling of on-line information for optimising nutrient removal
Authors: Nielsen M. K. , Önnerth T. B. 
Published: May 2018

Modern on-line measuring has given many new pieces of information which can reveal so far unknown details about load and process behaviour. This new information is primarily used for control optimisation purposes so that all available unused reserves in the plants during normal operation are used for improving the effluent quality and reducing operation costs. Secondly, the new on-line measurements can also be utilised for identifying the process relations as they are described in: a) software sensors, b) load characterisation and c) capacity of the actual plant.
Because of the 100 times more detailed information we now get from full-scale plant operation, more fundamental development and research can be carried out based on experiments performed directly on full-scale plants and evaluations of the on-line response to identify the model structure and constant dynamics at full scale. In this way it is possible to develop new processes significantly more quickly than before the on-line information was available.
To derive full profit from these improvements the following requirements must be met.
a) Measurement. Before identifying the process design constants it is necessary to compensate for the load applied on the full-scale system. This detailed evaluation is often so tedious that it normally has to be performed on an off-line basis, while the data from on-line measurements are brushed and used for on-line control, consequently the new kind of tools are needed in information handling.
b) The necessary excitations of the processes are always available during alternating operation. A condition for efficient control is controllability of the system; also in this respect the alternating system offers possibilities far more powerful than continuous systems.
c) Third, it is necessary to develop models and strategies which make the new knowledge and control possibilities operational.
The identified models, which are continuously updated, can be used for operational improvements which today give an excellent payback time for investment in on-line measurement and control systems. This is documented by introducing alternating operation which ensures the necessary information richness at plants with capacities down to below 20,000 PE.
This paper discusses the key points in the recommended approach to and structure of the information handling. The efficiency is demonstrated by introducing alternating operation on a conventional recirculating plant.
Advanced computer control based on real and software sensors
Authors: Önnerth T. B. , Nielsen M. K. , Stamer C. 
Published: May 2018

The introduction of state-of-the-art on-line meters is the first step towards achieving more intelligent operation of wastewater treatment plants as the directly involved parameters are known. The use of these on-line measurements is dependent on the reliability of the data, which is the control system STAR, Superior Tuning and Reporting, is secured by DQC, Data Quality Control. With reliable measurements combined with selected operational data, it is possible to identify process relations and implement on-line control strategies such as those performed by STAR today in oxygen set point control, intermittent aeration control and recirculation control.
Some of the STAR control functions are based on a certain kind of calculations described as software sensors, where information is achieved from qualified data and statistical data handling. Software sensors give an improved basis for on-line control strategies. These model-based “sensors” are available in an advanced process control systems such as STAR.
The results compiled at the Sydkysten WWTP show that the introduction of STAR control affords larger economies than expected. Today, the amount of energy consumed at the plant has been reduced by 30% and the dosing of carbon for denitrification by 100%. The economies achieved run into approx. DKK 470,000 per year and the new expense relating to the operation and maintenance of meters is, by comparison, DKK 55,000.
Modelling the transient impact of rain events on the oxygen content of a small creek
Authors: Jacobsen J. L. , Madsen H. , Harremoës P. 
Published: May 2018

Oxygen has been monitored in a small urban creek for a two months period. The purpose of the data collection is to use statistical modelling to obtain a better understanding of the phenomena governing the oxygen concentration. The long term goal is to influence the process of urban runoff to achieve oxygen concentration suitable for fish. Oxygen fluctuates significantly on a diurnal basis. Furthermore the purpose is to establish a model by which we are able to use rain data to estimate extreme values for comparison with standards for minimum oxygen concentration. The experience is that the fluctuations cannot be explained adequately on a deterministic basis alone. Significant stochastic variation has to be accounted for.
Data from a small stream is used to identify a dynamic model of the oxygen level as a function of solar radiation, water depth, and rain. The model is formulated in continuous time as two coupled stochastic differential equations. The continuous time formulation makes it possible directly to interpret the parameters of the model. Hence the model is useful for monitoring the actual state of the stream.
In this paper a grey box modelling approach, which is a statistical method taking the known physical relations into account, is used. This approach is closely related to the continuous time formulation. The parameters of the model are estimated using discrete time data and a maximum likelihood method. In evaluating the likelihood function a Kalman filter is used.
The dynamic model makes it possible to assess the transient impact of the urban runoff due to rain events, as well as the effect due to solar radiation. The ultimate outcome of the analysis is to determine the required size and location of storage basins to be constructed in the sewer system, in order to decrease combined sewer outflows and extreme oxygen depletion during rain.
Sewer sediments: preparation methods for enumerating bacteria
Authors: McGregor Iain , Souter Nicola H. , Ashley Richard M. 
Published: May 2018

In the UK, the Urban Pollution Management programme has contributed to extensive international research concerning solids associated with urban drainage systems.
Since 1986, as part of the UPM programme, research undertaken at the Wastewater Technology Centre, University of Abertay Dundee, has focused primarily upon the characteristics and movement of solids and associated pollutants in combined sewer systems.
These investigations have considered the behaviour of sediments and their attached pollutants during dry weather and storm flow conditions, and also the degree of pollutants associated with, and released from sewer sediments during periods of increasing sediment bed shear stresses. Data collection and sample analysis were driven by requirements specified for the development of a United Kingdom sewer flow model termed “MOSQITO”, with the basic chemical parameters ie; COD, BOD and ammonia, of sewage and sewer sediments. A data collection programme is described which assesses the feasibility of using combined sewer sediment preparation protocols, normally used for these chemical analyses, to enumerate bacterial indicator organisms present in deposited sediments. The data were analysed to investigate whether the methods used were precise in terms of repeatability, prior to more extensive studies being undertaken to provide sewer sediment data for bacterial numbers.
Technical solutions envisaged in managing solids in combined sewer networks
Authors: Chebbo Ghassan , Laplace Dominique , Bachoc André , Sanchez Yves , Le Guennec Benoit 
Published: May 2018

Solids in combined sewer networks represent two important technical questions:
- the clogging of man-entry sewers, and
- pollution in urban wet weather discharges, whose main vectors are generally suspended solids.
In this paper, we shall present first, curative technical solutions which avoid or remove deposits in man-entry sewers. We shall discuss the partial extraction of the largest solids; selective trapping of bed load solids, which form deposits; and the displacement of deposits using dry weather flow flushing waves.
We shall then examine technical solutions to control pollution in urban wet weather discharges. This will show that decantation is an efficient means of fighting pollution. However, it is not always feasible because it involves large scale investments. Complementary methods should, therefore, be developed and used at different points in the water's passage through an urban drainage area.
Petrochemical wastewater treatment with aerated submerged fixed-film reactor (ASFFR) under high organic loading rate
Authors: Park T. J. , Lee K. H. , Kim D. S. , Kim C. W. 
Published: May 2018

An aerated submerged fixed-film reactor (ASFFR) was developed to treat a petrochemical wastewater with high organic loading rate, where stationary submerged biofilms were attached to net-type media (SARAN 1000D) under diffused aeration. The specific surface area of SARAN 1000D was 400 m2/m3 approximately. The organic removal ability of the reactor was tested in three lab-scale ASFFRs. The reactor demonstrated 91.8-96.6% removal efficiencies of soluble chemical oxygen demand (SCOD) and exhibited efficient and stable performance at organic loadings of 1.02-6.21 kg COD/m3 day. When the media packing ratio increased the COD removal efficiency increased, while the effluent COD and SS concentrations were stable. The organic removal rates were dependent on the effluent SCOD concentration and the reaction orders were the same as or lower than 0.5.
Based on the experimental results, the ASFFR should be very suitable for treating petrochemical wastewater with relatively high organic loading rate.
Identifying and fighting inhibition of nitrification at Öresundsverket
Authors: Jönsson Karin , Magnusson Peter , Jönsson Lars-Erik , Hellström Bengt Göran , Jansen Jes la Cour 
Published: May 2018

After extension of Öresundsverket in Helsingborg severe nitrification problems have occurred. Complete inhibition of nitrification has been recognized once and a general reduction of nitrification capacity has been found compared to design, to other Swedish treatment plants and to internationally accepted design criteria.
A comprehensive examination of inhibition of nitrification has identified industrial sources as the dominating contributors. Some industries have been identified as important sources but fighting inhibition of nitrification requires more than tracking down a few dominating industries, since examination shows that discharges of inhibitory substances are widespread among the industries in the catchment area.
Naturally, fighting inhibition of nitrification requires the elimination of contributions from industries with identified discharge. Furthermore information campaigns directed towards the industries in general are required and finally it is necessary to include requirements for inhibitory substances in the industrial discharge permits.
Design and construction of aeration systems for optimum operation of large wastewater treatment plants
Authors: Bischof Franz , Höfken Marcus , Durst Franz 
Published: May 2018

The construction and operation of large wastewater treatment plants are very important tasks today. Choosing the optimum process design can help to keep initial costs low. Careful operation and modern equipment reduces the operational costs. Taking into account the huge demand (Anonymous EEC-Report 1990) for new wastewater treatment plants or plants which need to be upgraded after the new EEC legislation concerning sewage treatment came into force in May, 1991 (Anonymous EEC-Guideline 1991) it is quite clear that only cost-effective processes supported by energy-efficient equipment are the answer to economical wastewater treatment. Regarding the operational costs for biological treatment, approximately 70% of the total energy consumption is used for the activated sludge part of the treatment plant, i.e. for the stirring and aeration systems (Höfken et al. 1992). That shows how important the proper design of such systems is and implies that only innovative and energy-efficient equipment should be used.
This paper presents theoretical considerations for the design of aeration systems for aerobic processes. These considerations lead to recommendations for the construction and the operation of aeration systems.
Stability and variation in sludge properties in two parallel systems for enhanced biological phosphorus removal operated with and without nitrogen removal
Authors: Lee Natuscka M. , Carlsson Hans , Aspegren Henrik , Welander Thomas , Andersson Bengt 
Published: May 2018

In order to introduce nitrogen removal, many conventional activated sludge systems in Sweden have been transformed into low-loaded systems during the 1990's. Occasionally these systems have been combined with enhanced biological phosphorus removal (EBPR). Increased problems of sludge loss from secondary clarifiers have aroused new interest in the properties of activated sludge. The aim of this study was to investigate the long-term variation and stability of sludge properties in two parallel EBPR systems, operating on the same wastewater. One of the systems was designed as a conventional system, and the other as a low-loaded system with nitrogen removal. The study was performed at the Sjölunda plant in Malmö during a two-year period, in a pilot plant which has been in operation since 1986.
The diluted sludge volume index (DSVI) was found to be about 150 ml/g in both systems. The highest values were recorded during the winter season. The variation in the DSVI was much greater in the conventional system than in the low-loaded system. The dominating filamentous bacteria in the conventional system were Type 021N and Thiothrix, and in the low loaded system Type 0041/0675 and Type 0092. The EBPR operation induced large amounts of poly-P-containing flocs in both systems. Although it was not possible to determine to what extent the poly-P-containing flocs affected the sludge properties in this study, it was clearly demonstrated that EBPR operation may not always provide conditions which lead to superior sludge properties.
Biological-ion exchange process for ammonium removal from secondary effluent
Authors: Green Michal , Mels Adriaan , Lahav Ori , Tarre Sheldon 
Published: May 2018

A new concept for ammonium removal from secondary effluent by zeolite followed by bio-regeneration has been studied. In contrast to other studies of hybrid biological-ion exchange multireactor systems, the proposed process uses the ion exchange material, zeolite, as the carrier for the nitrifying biomass. This enables the two mode process to be carried out in a single reactor.
In the first mode (ion exchange), secondary effluent is passed through an ion exchange column where ammonium is concentrated in the zeolite. During the second mode (bioregeneration), the absorbed ammonium is released gradually and converted to nitrate by the active biomass residing on the zeolite. Nitrification is carried out batchwise and in a small volume reactor where optimal conditions can easily be maintained. Moreover, the addition of chemicals for the desorption of ammonium is minimal due to regenerant reuse during several cycles of nitrification. As a result, operational costs and production of large volumes of brine are minimized.
Batch and breakthrough experiments showed that the amount of ammonium adsorbed on the chabazite is strongly affected by the presence of competing cations present in secondary effluent. A reduction of about 75% was observed when using a typical Israeli sewage ion composition. The attached biomass did not significantly effect the efficiency of the ion exchange column.
Ammonium desorption experiments showed that regeneration with 10,000 mg/L Na+ is much faster than with 2440 mg/L (more than 90% ammonium recovery after 40 and 70 bed volumes, respectively).
A nitrification rate of 6 g NH4-N/(L reactor *day) was obtained in a fluidized bed reactor with chabazite as the carrier. Although this rate is in the high range of reported values for biofilm reactors, desorption experiments proved that nitrification will be the process's rate limiting step, rather than the desorption rate when regenerant solutions as low as 2440 mg/L Na+ are used.
Overall chemical reaction model of an ozone contactor for a water purification model
Authors: Kageyama K. , Watanabe S. , Baba K. , Komatsu N. , Yamakoshi N. 
Published: May 2018

For the removal of odorous compounds such as dimethylisoborneol (2-MIB) and trihalomethanes (THMs) in supplied water, advanced water treatment plants using ozonation and activated carbon absorption processes have been built in Japan. This paper describes an over-all chemical reaction model for the ozone contactor of the ozonation process. In this model, the Potassium Permangante Consumed (PPC) is assumed as an index of typical ozone consuming substances. The experimental data and calculated results for the ozone consuming substances are compared with Total Trihalomethanes Formation Potential (TTHMFP). Furthermore, the promotive or inhibitive reaction of 2-MIB is introduced in the model. This allows the mathematical model to be applied to actual raw water containing many kinds of co-exist substances.
The model appropriateness is discussed using pilot plant data for a year's operation.
Environmental and energy efficiency of different sewage treatment processes
Authors: Karlsson Ingemar 
Published: May 2018

This paper summarises the Scandinavian experience that chemical wastewater treatment gives “value for money” in the sense that such treatment gives a low construction volume per removed unit of Oxygen Consumption Potential (OCP) in the receiving water and a low energy consumption per unit of Oxygen Consumption Potential (OCP) removed. The OCP evaluation takes into consideration both the primary oxygen consumption caused by organic matter and ammonium as well as the secondary oxygen consumption from degradation of algae resulting from the discharge of nutrient. The paper demonstrates that in comparison to conventional biological activated sludge treatment (with pre-settling), chemical treatment plants (primary precipitation) are cheaper in terms of cost per unit of OCP removed and that they require less energy per unit of OCP removed. Chemical treatment is considered to be the most suitable method when discharging municipal sewage to sensitive marine receiving waters and should be categorized as secondary treatment, like biological treatment.
It is important when ecological aspects are considered, for instance in terms of energy consumption, that all elements that contribute to the total consumption of energy must be included. For instance, a compact treatment plant, like a chemical one, may require less energy for concrete, while it requires more energy for chemicals. The problem is evaluated in two different ways: (i) an evaluation of energy consumption based on the major energy-associated elements: chemicals, air and biogas; and (ii) an analysis of all ecological aspects based on a model for evaluating the ecological value of the products and processes.
The effect of chemical bulking control on biological nutrient removal in a full scale activated sludge plant
Authors: Saayman G. B. , Schutte C. F. , van Leeuwen J. 
Published: May 2018

The use of chemicals for sludge bulking control has a direct effect on the biological nutrient removal processes in activated sludge systems designed for this purpose. Chlorine has been used on full scale but information on the use of ozone and hydrogen peroxide is limited to pilot scale tests.
The objective of this study was to investigate the effects of chlorine, ozone and hydrogen peroxide on nutrient removal processes when used on a continuous basis for bulking control in a full scale biological nutrient removal activated sludge plant. The full scale studies were conducted over a period of 39 months at the Daspoort sewage works of the City Council of Pretoria.
The results indicate that at low dosages the oxidants have limited effects on the nutrient removal processes but at higher levels chlorine had a detrimental effect resulting in the phosphate limit of 1 mg P.1−1 being exceeded.
It is concluded that chlorine is the most effective of the three oxidants for bulking control, but that it should be used with caution in order not to upset the biological phosphate removal processes. Ozone at low levels had a small but consistent positive effect on bulking control as well as on nutrient removal. The effects of hydrogen peroxide were very small except at high dosages.
Nitrite accumulation in submerged biofilters - combined effects
Authors: Fdz-Polanco F. , Villaverde S. , Garcia P. A. 
Published: May 2018

The combined effect of temperature, pH and ammonium concentration over the nitrite accumulation phenomena in situations of free ammonia inhibition, their effect over the ammonia and nitrite oxidizer microorganiisms influence over the nitrification, have been studied in an Up-flow Biological Aerated Filter (UBAF).
The free ammonia inhibition effect highly depends on the values of pH, temperature and ammonium concentration. For the same specific free ammonia concentration different values of temperature, pH and ammonium concentration bring about different nitrite accumulations. In conditions of no free ammonia inhibition and low values of temperature and pH, high ammonium concentrations bring about a higher relative activity of ammonia oxidizer microorganisms of the filter increases the nitratation efficiency in zones close to the outlet and will favour the nitrite accumulation in situations of free ammonia inhibition.