bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical disintegration of sewage sludge
Authors: Lehne G. , Müller A. , Schwedes J. 
Published: May 2018

Mechanical disintegration can be used for an accelerated and improved anaerobic digestion of excess sludge. The hydrolysis is the limiting step of this process. Mechanical disintegration can be used to disrupt the cell walls and to cause the release of the organic material from the cells. Particle size analysis describes the size reduction but is not suitable for characterising the release of the organic material and the cell disruption. Two biochemical methods were developed for these phenomena. One of the parameters provides information about the disruption of micro-organisms, the other one gives information about the release of organic material.
Different ultrasonic homogenizers, a high pressure homogenizer and stirred ball mills were used for disintegration experiments using various parameters. The influences of a mechanical disintegration on the particle size and of the energy intensity on the disintegration were investigated. Further investigations had to detect the influence of the solid content on the disintegration results. For sludge with a higher solid content better results in terms of energy consumption could be achieved. An optimum of the bead diameter and the stress intensity in stirred ball mills could be detected. A comparison of the results of different methods of sludge disintegration shows that the investigated ultrasonic homogenizers are inferior to a high pressure homogenizer and a stirred ball mill in terms of energy consumption.
Full-scale demonstration of biological nutrient removal in a single tank SBR process
Authors: Keller J. , Watts S. , Battye-Smith W. , Chong R. 
Published: May 2018

Complete biological nutrient removal (BNR) in a single tank, sequencing batch reactor (SBR) process, is demonstrated here at full-scale on a typical domestic wastewater. The unique feature of the UniFed process is the introduction of the influent into the settled sludge blanket during the settling and decant periods of the SBR operation. This achieves suitable conditions for denitrification and anaerobic phosphate release which is critical to successful biological phosphorus removal. It also achieves a “selector” effect, which helps in generating a compact, well settling biomass in the reactor.
The results of this demonstration show that it is possible to achieve well over 90% removal of COD, nitrogen and phosphorus in such a process. Effluent quality achieved over a six-month operating period directly after commissioning was: 29 mg/l COD, 0.5 mg/l NH4-N, 1.5 mg/l NOx-N and 1.5 mg/l PO4-P (50%-iles of daily samples). During an 8-day, intensive sampling period, the effluent BOD5 was &lt;2 mg/l in all samples and the total phosphorus averaged 0.17 mg/l in the effluent. Detailed sampling and analysis during one cycle and at various depths clearly showed the deliberate stratification achieved in the tank during the settling and decant period, allowing biochemical reactions to occur during this normally “non-productive” period.
The simplicity and flexibility of the UniFed system allows it to be used in numerous applications, particularly for industrial situations where a high degree of uncertainty of the wastewater composition during the design stage or where changing requirements based on changes on the production side are present. The single tank operation without any recycle also reduces the capital costs for a full BNR system compared to the comparatively complex continuous flow processes.
Ecology and equity: key determinants of sustainable water security
Authors: Swaminathan M. S. 
Published: May 2018

Trends in water consumption indicate that demand for water for household and industrial uses in developing countries could double as a proportion of total water demand in the next 25 years. Scope for expansion of water supply will, at the same time, be limited because development of irrigation and urban water supplies is becoming increasingly expensive, and often involves high costs in terms of environmental degradation and human resettlement. Without fundamental reform of water management, the rapid growth in urban water demand will require large transfers of water from irrigated agriculture, thereby threatening food security. Hence, water supply and demand should be managed in an integrated fashion, simultaneously considering all uses and sources. This will call for the establishment of community centred food and water security systems and national water trusts.
Once such systems and Trusts are established there could be a legally binding Global Water Convention on the model of the Global Convention on Climate and Biodiversity. The details of such a Global Water Conventions can be finalized at one of the future Stockholm Water Symposia. There are uncommon opportunities today for a water-secure world through synergy between technology, public policy and peoples‘ participation.
Integration of chemical and biological treatments for textile industry wastewater: a possible zero-discharge system
Authors: Lee H.H.W. , Chen G. , Yue P.L. 
Published: May 2018

Theoretical and experimental studies have established that integrated treatment systems (mostly chemical and biological) for various industrial wastewaters can achieve better quality of treatment and can be cost-effective. In the present study, the objective is to minimize the use of process water in the textile industry by an economical recycle and reuse scheme. The textile wastewater was first characterized in terms of COD, BOD5, salinity and color. In order to recycle such wastewater, the contaminants should be mineralized and/or removed according to the reusable textile water quality standards. Typical results show that this is achievable.
An economic analysis has been conducted on the proposed integrated system. The economic analysis shows that the integrated system is economically more attractive than any of the single treatment technologies for achieving the same target of treatment. The information presented in this paper provides a feasible option for the reduction of effluent discharges in the textile industry.
Small diameter gravity sewers: self-cleansing conditions and aspects of wastewater quality
Authors: Dias S. P. , Matos J. S. 
Published: May 2018

The construction of conventional sewerage systems in small communities, with pipes laid on a uniform slope and manholes regularly spaced, is sometimes not economically feasible, because of the high costs of sewer installation. Under those circumstances, the small diameter gravity sewers (SDGS) have often proven to be substantially less costly than conventional sewers. Typically, in SDGS systems the wastewater from one or more households is discharged into an interceptor tank (or a single compartment septic tank). The settled effluent is discharged afterwards into small diameter sewers operating under gravity.
In this paper, special emphasis is given to the analysis of self-cleansing conditions and to the analysis of risks of sulphide generation and occurrence of septic conditions in SDGS systems. For the evaluation of the self-cleansing conditions, the critical velocity and the critical shear stress were computed according to the Shields equation. The forecasting of dissolved oxygen concentrations and sulphide build-up along the lines, for different flow conditions, was done running an established wastewater quality model.
Sustainable development in pollution control and the role of anaerobic treatment
Authors: Lettinga G. , Van Lier J. B. , Van Buuren J. C.L. , Zeeman G.. 
Published: May 2018

The increasing scarcity of clean water sets the need for appropriate management of available water resources. Particularly regions suffering from a lack of water urgently need integrated environmental protection and resource conservation (EP and RC) technologies in order to enable effective management of the available water resources. EP and RC-concepts focus on pollution prevention and on a minimum of consumptive use of energy, chemicals, and water in pollution abatement and a maximum of re-use of treated wastewater, by-products and residues produced in the treatment of waste and wastewater. Consequently, by implementing these concepts, waste(water)s like sewage and industrial effluents become an important source of water, fertilisers, soil conditioners and (frequently) energy instead of a social threat. In addition, a bridge is made between environmental protection and agriculture practice, stimulating (urban) agriculture in the neighbourhood of large cities.
Anaerobic treatment is considered as the core technology for mineralising organic compounds in waste(water) streams. Additional technologies are required to comply with the reuse criteria. Some examples of possible EP and RC concepts, using the anaerobic treatment technology for the reclamation of domestic sewage are discussed.
Parameter optimisation of real-time control strategies for urban wastewater systems
Authors: Schütze M. , Butler D. , Beck M. B. 
Published: May 2018

Real-time control (RTC) of wastewater systems has been a topic of research and application for over two decades. Attempts so far have mainly focused on one of the parts of the urban wastewater system: either the sewer system, or the treatment plant or the river. Approaches to integrate these subsystems and considering them jointly for control purposes have been pursued only recently. Control of the system aims at pursuing one (or several concomitant) objectives, which are expressed, for example, in terms of overflow volumes, loads, effluent concentrations, receiving water quality or monetary costs, to name just a few.
This paper provides a general and formal definition of the problem to define a real time control algorithm for a given urban wastewater system. A general mathematical optimization problem is formulated, which describes the task of finding an (in some sense) optimum control algorithm. Since this optimization problem is, in the general case, highly non-linear with only limited information available about the objective function itself, optimization methods appropriate for this type of problem are identified. Here, the similarity of the problem to find a control algorithm and of the parameter estimation problem common in mathematical modelling becomes apparent. Hence, methods (and problems encountered) in parameter estimation can be transferred to the problem of determining optimum RTC algorithms. This parallelism is outlined in the paper.
As an application of the parameterisation and optimization of control strategies, integrated control of an urban wastewater system is discussed. Since the analysis of integrated control as just described poses certain requirements on a simulation engine, a novel modelling tool, called SYNOPSIS, is utilized here. This simulation tool, comprising of modules simulating water quantity and quality processes in all parts of the urban wastewater system, is embedded into a suite of optimization procedures. An integrated RTC algorithm for the urban wastewater system is formulated, the parameters of which are optimized using various global optimization routines. Comparison of their efficiency indicates good performance for the Controlled Random Search and for the genetic algorithms. The findings suggest that integrated control can indeed lead to an increase in performance of the urban wastewater system. These results appear to be encouraging and justify further work. Areas for further development are identified in the final section of the paper.
Fast, simultaneous simulation of the integrated urban wastewater system using mechanistic surrogate models
Authors: Meirlaen J. , Huyghebaert B. , Sforzi F. , Benedetti L. , Vanrolleghem P. 
Published: May 2018

The urban wastewater system components (sewer, treatment plant, and river) are often modelled using complex mechanistic models. Mechanistic surrogate models are introduced here as simplified models that still contain some physical knowledge. Surrogate models are faster, but are less but still sufficiently accurate, and require more data to be calibrated. The possibilities of replacing actual field data by virtual data generated with a complex mechanistic model for calibration of the surrogate model are examined. As an example, a series of tanks with variable volume is shown to approximate sufficiently well the flow propagation in the river Zwalm (Belgium) as predicted by the “de Saint-Venant” equations.
The three surrogate models can be implemented in the WEST® simulator, which makes a simultaneous simulation of the system possible. In this work a connection is made between the ASM1 and the new IWA River Model No. 1 (RWQM1) by using a translator between the models in such a way that both mass and elemental balances remain closed for the overall system. This approach is illustrated with a case study on the river Lambro (Italy). The dispersion process in this river with steady flow could be modelled by using a tanks in series model, while the water quality in the river was predicted to improve substantially with an increase in hydraulic capacity of the treatment plant. The simulation results with the upgraded plant still need to be checked by field data.
Collision efficiency factor of bubble and particle (abp) in DAF: theory and experimental verification
Authors: Han M. , Kim W. , Dockko S. 
Published: May 2018

The collision efficiency factor of bubble and particle (αbp) in dissolved air flotation (DAF) can be calculated theoretically by trajectory analysis, which takes into account both hydrodynamics and inter-particle forces. To determine the theoretically optimum particle size for any given bubble size, a collision efficiency diagram for DAF was developed where collision efficiency is contoured on a plane of particle and bubble sizes for different conditions of particle zeta potential.
A set of experiments tested the validity of the suggested collision efficiency diagram, and examined whether pretreatment is important and why slight coagulant overdosing and shorter flocculation times are generally preferred in DAF, both current accepted practice. Batch DAF reactors were used and kaolin samples were prepared from jar tests using different alum dosages and flocculation times. The particle size distribution, particle zeta potential, and turbidity removal in each experiment were measured, as were bubble size and zeta potential.
The results agreed well with the predictions of the collision efficiency diagram and explained current practices. A collision efficiency diagram identifies the pretreatment goal, i.e., tailoring of the optimum characteristics required of particles (zeta potential and size) under existing operational bubble characteristic.
Managing waterway health in the Goulburn Broken Catchment, Victoria, Australia
Authors: Tennant W. , Sheed J. 
Published: May 2018

Historically within most catchments, resource management programs have been planned and implemented in isolation of one another. This was once the case in the Goulburn Broken Catchment, a major catchment of the Murray Darling Basin, Australia. Although only 2% of the Murray Darling Basin's land area, the catchment generates 11% of the basin's water resources.
Learning from the past, a cooperative and collaborative approach to natural resource programs has developed. This approach is the envy of many other catchment communities and agencies. Through a combination of “Partnership Programs”, “Operational Initiatives” and community involvement, significant programs have been implemented within the catchment, which will benefit not only the local community but communities further afield. The outcomes of the waterway health program highlight the benefits provided through the establishment of cooperative and partnership resource improvement programs. These programs were founded on the ability of the community to recognise the need for integration, base management decisions on best available science and an ability to work together. Their effective delivery has been provided through the resources provided, to the local community, by the Natural Heritage Trust with matching and State and local allocations.
While programs have shown success, challenges still face the community. These challenges include verification and implementation of environmental flows, storage of the catchment's vital water resources, and maintaining community involvement and participation in on-going works programs. The Goulburn Broken Catchment community, with the support of Federal, State and Local Governments, is looking at opportunities for continued improvements in waterway health.
From river to ridge: a blueprint for sustainable management in the Georges River Catchment
Authors: Nimmo J. 
Published: May 2018

Research on sustainable transport and water projects, conducted in North America during 1999, identified four key considerations common to a number of projects. These four considerations are the pre-conditions necessary to achieve sustainability in a given location. These preconditions (BAPP) are boundary definition, administrative alignment, protection of non-urban lands, and the participation of all interested parties.
This paper considers the perceived attitudes of various catchment stakeholders and focuses on planners and planning. The results of questionnaire surveys based on BAPP concepts suggest that local government is perceived as having the highest priority for protection of riparian lands and waterways (as individual Councils and Regional Organisations of Councils). Thus local government is the preferred arena for coordination, responsibility and jurisdiction of waterways and riparian land. The opportunity exists to examine the differing roles of local and state government. The paper concludes by outlining the implications of this research for land use planning and institutional structures in sustainable river management.
Prediction of the dewatering of selected inorganic sludges
Authors: Harbour P.J. , Aziz A.A.A. , Scales P.J. , Dixon D.R. 
Published: May 2018

There are a number of laboratory techniques traditionally used in the characterisation of sludges for the prediction of the efficient operation of dewatering processes such as centrifugation and filtration. In industry, capillary suction time and specific resistance to filtration measurements are common. Whilst useful in predicting trends, they do not assist in the design and optimisation of devices from first principles.
Recent work in our laboratories has developed a technique for the fast measurement of the permeability and compressibility of sludge. This information, when coupled with first-principle models is useful for the prediction of the performance of solid-liquid separation devices. The work has shown that a single volume fraction dependent parameter, namely the solids diffusivity, calculated from permeability and compressibility, is able to fully characterise the dewaterability of sludge. This allows different sludges to be compared in an unequivocal fashion.
Data will be presented for a range of sludges from different sources showing vastly different dewatering properties. The dewaterability of the different sludges is easily compared and the true role of flocculants in dewatering is highlighted.
Chemical and physical pretreatment of ATAD biosolids for dewatering
Authors: Abu-Orf M.M. , Griffin P. , Dentel S.K. 
Published: May 2018

This paper reports on two modifications to the typical practice of polymer conditioning intended to enhance the dewaterability of autothermal thermophilic aerobic digested (ATAD) biosolids. One modification was a chemical pretreatment, using ferric chloride prior to polymer conditioning, and the other was a physical pretreatment using an electrical arc technology before polymer addition. These modifications were evaluated separately and in combination, in laboratory conditioning experiments using ATAD biosolids.
Results showed that neither ferric chloride nor the arc treatment is sufficient to produce dewaterable biosolids without the use of polymer. However, use of a ferric chloride dose as low as 100 g per kg of dry solids reduced the polymer requirement by about 50%. The arc treatment provided further enhancement of dewaterability, but the observed benefits might not justify its use without further optimization. For this purpose, additional methods were utilized to assist in understanding the pretreatment mechanisms.
Six years' practical experience with aerobic/anoxic deammonification in biofilm systems
Authors: Hippen A. , Helmer C. , Kunst S. , Rosenwinkel K.-H. , Seyfried C. F. 
Published: May 2018

Nitrogen elimination through autotrophic micro-organisms is currently in the focus of research projects on the treatment of wastewater with high nitrogen contents, for instance to be able to develop and fix dimensioning parameters for purposeful application. In fact, several industrial plants have already shown for some years that the steady operation of nitrogen elimination without carbon demand is possible. Due to the low growth rates of the participating micro-organisms, these processes can be found in particular in biofilm systems, which also allow for the simultaneous running of the two basic processes.
In the following, we will discuss on the basis of the operation results of industrial and pilot-scale plants the operation stability of the aerobic/anoxic deammonification, and explain which experiences are available in particular for conversion in biofilm systems.
Choice of the sand for sand filters used for secondary treatment of wastewater
Authors: Liénard A. , Guellaf H. , Boutin C. 
Published: May 2018

In a range from 100 to about 1,000 People Equivalent (PE), Secondary Wastewater Sand Filters (SWSF) are used by a lot of rural communities in France. A series of case studies however point out that several criteria concerning global and detailed design and implementation of these systems have to be approached scientifically, in order to obtain the expected results on a long-term basis.
The choice of the sand constituting the infiltration bed, core of the biological reactor, is of course one of the key elements and is the main subject of this article. It must have a sufficient initial permeability in order to ensure an adapted infiltration speed, after colonisation by the purifying biomass. The d10 fines content and degree of uniformity mainly control this permeability. The quarry or the aggregate extractor, who masters his production this way, usually gives these elements, based on granulometric analysis. However the adjustment of an infiltration test with clear water is essential to check on site the conformity of the deliveries.