bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modelling to solve odour problems
Authors: Childs P. S. , Dunn A. J. 
Published: May 2018

The use of dispersion modelling is a powerful tool to establish levels of treatment required to remove odour complaints. Odour is an extremely sensitive issue and is key to the public perception of wastewater environmental protection. This paper describes a case study of the successful resolution of long-standing odour problems at the East Worthing Wastewater Treatment Works (WTW), on the South Coast of England, utilising modelling and appropriate treatment technologies.
A number of odour surveys have been conducted on the site to identify the major sources on the works, which were found to be the sludge press house and the primary settlement tanks, situated only 10 metres from the nearest properties. As a result attempts to resolve the odour problem have been made including the covering of identified sources, treating extract using activated carbon filters and installing perfume sprays.
During the site development all sources were contained and ventilated to a 60,000 m3/hr Jones & Attwood ODORGARDTM unit. Its requirement was to ensure that no receptor was exposed to a concentration in excess of 4 ouEm3 (Odour units), in accordance with the odour planning condition.
Dispersal modelling was performed to determine the maximum permissible outlet concentration. The results of the modelling exercise established that emissions from the odour control plant should not exceed 675 ouEm3 to ensure that the receptor standard was attained. An optimisation programme was conducted to ensure that the unit was providing the optimum level of treatment prior to taking the olfactometry samples.Following the plant's optimisation the results of the olfactometry analysis confirmed that the discharge levels were below the required 670 ouEm3. Since completion of the sludge treatment centre scheme there have been no registered odour complaints directed at the East Worthing WTW, and the local air quality has been greatly improved for the residents surrounding the works.
Effect of residence times on River Mondego estuary eutrophication vulnerability
Authors: Duarte A. S. , Pinho J. L. , Pardal M. A. , Neto J. M. , Vieira J. P. , Santos F. S. 
Published: May 2018

The south arm of the Mondego estuary, located in the central western Atlantic coast of Portugal, is almost silted up in the upstream area. So, the water circulation is mostly driven by tides and the tributary river Pranto discharges. Eutrophication has been taking place in this ecosystem during last twelve years, where macroalgae reach a luxuriant development covering a significant area of the intertidal muddy flat.
A sampling program was carried out from June 1993 to June 1994. Available data on salinity profiles and on nutrients loading into the south arm were used in order to get a better understanding of the ongoing changes. River Pranto flow discharges, controlled by a sluice, were also monitored. Integral formulations are typically based on assumptions of steady state and well-mixed systems and thus cannot take into account the space and time variability of estuarine residence times, due to river discharge flow, tidal coefficients, discharge(s) location and time of release during the tidal cycle. This work presents the hydrodynamics modelling (2D-H) of this system in order to estimate the residence times variability and to assess their effect on the estuarine eutrophication vulnerability, contributing to better environmental management strategies selection.
The use of macrophyte-based systems for phosphorus removal: an overview of 25 years of research and operational results in Florida
Authors: DeBusk T.A. , Dierberg F.E. , Reddy K.R. 
Published: May 2018

Phosphorus (P) removal from wastewaters and surface runoff using macrophyte-based systems (MBS) has been a topic of great interest in Florida for over 25 years. During this period, P removal by both treatment wetlands and floating aquatic macrophyte systems has been evaluated from both a research and operational standpoint. Several factors have contributed to the increased focus on the use of MBS for P removal. First, there exist no conventional technologies that can cost-effectively achieve the low outflow P concentrations required to protect the integrity of Florida's relatively pristine surface waters. Second, because MBSs typically provide some water storage, they can accommodate the wide ranges of flows typical for runoff sources such as agricultural drainage waters. Finally, many regions in Florida have sufficient area for deployment of the relatively land-intensive MBS technologies.
The first P removal work in Florida was initiated in the mid-1970s, and involved pilot-scale research on domestic wastewater treatment by natural wetlands. Parallel studies were performed with managed (periodically harvested) floating plant systems (i.e., Eichhornia crassipes) for tertiary treatment. Since that time, the range of operational systems that have been deployed include emergent macrophyte-based and forested wetlands, managed floating plant systems, and submerged macrophyte-based systems. Waters treated by MBS include domestic effluents, agricultural runoff and eutrophic lake waters. Phosphorus removal targets for MBS in Florida have been as low as 10 μg/L. In this paper, we summarize research and operational results for MBS in Florida over the past 25 years.
Nutrient removal in subsurface flow constructed wetlands for application in sensitive regions
Authors: Rustige H. , Platzer Chr. 
Published: May 2018

One of the most interesting sites for research on CWs in Germany has been established in Wiedersberg (Saxonia). The multi-stage concept with primary settling, vertical and horizontal flow reed bed followed by UV-disinfection and a special phosphorus filter bed, allows numerous ways of operation and investigations. Denitrification can be improved by recirculation through VF bed and sedimentation tank or by means of adding carbonaceous water from the primary stage to a second level within the VFB or directly to the following HF bed. In order to investigate the efficiency of P-elimination four kinds of natural sands containing different amounts of iron have been used. To maintain a long-term capacity for P-reduction an additional filter bed is filled with gravelly sand which had been used for the precipitation of iron from drinking water before. After saturating with P this filter medium can be exchanged easily.
A result of more than one year of operation is the high performance rate for adsorption of phosphorus by enriched iron on drinking water filter sand. At a total loading rate of 350 g P/m3 filter medium 250 g P/m3 have been adsorbed. Design considerations can not be given yet. The median denitrification rate at VFB is 1.3 g N m-2d-1 and at HFB is 0.25 g Nm-2d-1. The low denitrifcation rate of HFB might be due to a very high quota of wastewater dilution by storm- and ground-water of 100 to 200 percent. The investigations on this wastewater treatment plant will be continued until June 2001 and experiments with filter columns will be added.
Rivers as urban landscapes: renaissance of the Waterfront
Authors: Benson E. 
Published: May 2018

The Lake Ontario Waterfront Trail, currently stretching 350 kilometres along the shore of Lake Ontario, Canada, links 26 communities, 184 natural areas, 161 parks and promenades, 84 marinas and yacht clubs, hundreds of historic places, fairs, museums, art galleries and festivals. The Waterfront Trail is a catalyst for a new attitude and way of thinking towards the Lake Ontario waterfront and its watersheds - one that integrates ecological health, economic vitality and a sense of community.
Since it was launched in 1995, the Trail has accompanied the protection of the most valued elements of the waterfront, and the transformation of under-utilized and environmentally degraded lands to vibrant places with businesses and jobs, parks and recreational facilities, green spaces, natural habitats and cultural venues and attractions. It is through the Trail that people have been mobilized to improve the waterfront as they have rediscovered the shoreline and understood the interconnections, both natural and cultural, that are so vital to its health and vitality.
The Waterfront Regeneration Trust is the not-for-profit charitable organization that has been leading this large-scale greenway initiative over the past 10 years. While much has been accomplished, there remains much to do to enhance and expand the greenway. This presentation will focus on the lessons we have learned over the past decade in our involvement with more than 100 projects and what those lessons mean for the next decade of waterfront regeneration.
Community-based stream conservation initiatives in British Columbia, Canada
Authors: Wilson N. 
Published: May 2018

British Columbia is a diverse province, with ecosystems ranging from semi-arid deserts to valley glaciers and vast ice fields. By world standards, BC has an abundance of fresh water in its lakes and rivers. However, rivers have been exploited for social and industrial purposes, often to the detriment of the natural values. Community groups and non-government organizations have been active in rehabilitating and restoring waterways.
The Outdoor Recreation Council of BC is a provincial non-government organization that has been instrumental in river conservation issues in BC. Three key initiatives have been established by the Council since its formation in 1975. BC Rivers Day has grown into the largest river celebration of its kind in North America, and there is a move to establish a national Rivers Day in Canada based on the model established in BC. Second is the annual Endangered Rivers List compiled by the Council and released each spring. The third initiative is the River Recovery Project in which dams and impoundment structures were evaluated against a set of criteria. A short list of candidates was generated by the project that will be further studied to determine what actions should be taken to alter the management of the structures to restore ecological values of the rivers and streams on which they are built.
The three initiatives described rely on local community support. The Outdoor Recreation Council of BC provides coordination, promotion, and publicity as well as some resource materials while local groups and communities take on stewardship roles for their local streams. This model may be useful for other jurisdictions.
Production of gaseous nitrogen compounds in a novel process for ammonium removal
Authors: Green M. , Denekamp N. , Lahav O. , Tarre S. 
Published: May 2018

The production of gaseous nitrogen compounds, particularly the greenhouse gas nitrous oxide, was investigated in a novel process for ammonium removal from wastewater. The process is based on the adsorption of ammonium on zeolite followed by bioregeneration. The zeolite serves the dual purpose of an ion exchanger and a physical carrier for nitrifying bacteria which bio-regenerate the ammonium saturated mineral. An analysis of the nitrifying population composition in the reactor fed with simulated secondary effluent (NH4+ = 50 mg/l) revealed that about half of the bacteria in the biofilm were common ammonium oxidizers Nitrosococcus mobilis and Nitrosomonas, while the other half were nitrite oxidizers.
The amount of nitrogen losses, under different conditions, and the identification of the emitted gases (N2 or N2O) were investigated in two sets of experiments: (I) batch experiments using biomass originating from the ion exchange reactor with and without the addition of nitrite, and (II) continuous experiments using the ion exchange reactor with zeolite as the biomass carrier. In the batch experiments, nitrite and oxygen concentrations were determined as the major parameters responsible for the formation of gaseous nitrogen gas during ammonia oxidation by autotrophic bacteria. Continuous experiments showed that the major parameter significantly affecting nitrogen losses was the amount of ammonium adsorbed by the zeolite during the ion exchange phase. The amount of ammonium adsorbed determines the ammonium concentration during the initial period of bioregeneration, which in turn directly influences oxygen demand and the resulting concentrations of oxygen and nitrite. It was concluded that the formation of nitrogen gas compounds in the ion exchange/bioregeneration process can be eliminated by adjusting the operational regime to have a shorter adsorption phase resulting in smaller amounts of ammonium adsorbed per cycle.
Investigation of anaerobic zone short-circuiting using computational fluid dynamics
Authors: Sherwin C. , Ta C.T. 
Published: May 2018

Flow characteristics of anaerobic zone was investigated using the computational fluid dynamics technique. The tank is an inlet/outlet baffle tank with two impellers to provide additional energy to prevent solid settlement. The turbulent flow was modelled using the standard k-e model and the rotation of the impellers was modelled using the multiple rotating frame of reference technique. The model simulated tracer results and was in reasonable agreement with measurement. Solid settlement was tracked using the Lagrangean disperse phase tehnique.
Flow in anaerobic zone exhibited completely mixed behaviour with short-circuiting. A number of options were investigated. All exhibited the general completely mixed system, which resulted from the flow circulation around the central baffle. Some options, however, led to major short circuiting and were avoided. The function of the impellers was to maintain the flow circulation and to prevent solid settlement.
Ozonation of domestic secondary effluent for recycling and reuse - a pilot plant study
Authors: Ni C.H. , Chen J.N. , Tsai Y.C. , Chen W.B. , Chen C.H. 
Published: May 2018

In this study, a pilot plant combined ozonation with sand filtration is established. Wastewater from the secondary effluent was taken as the sample for looking into the feasibility of domestic wastewater recovery and recycling.
At the beginning, a series of hydraulic analysis and ozone transfer tests was conducted in the bubble column reactor. From these tests, it was found that when the gas flow is controlled to within 0.2∼1.0 L/min and liquid flow within 0.5∼2.5L/min, using series connected mixing tank model for our calculation, the result J (CSTR) is 1∼2. From the ozone transfer test it is known that the smaller the gas flow, the better the transfer rate, and the same pattern occurs on ozone gas concentration. After sand filtration and ozone treatment, the G/L ratio within the ozone column reactor can be maintained within 0.2∼0.4 and the ozone dosage within 8∼12 mg/L. The removal rate for coliform bacillus, BOD, turbidity and color is 99.96%, 62.2%, 89.6% and 67% respectively.
After ozonation treatment, coliform bacillus content can be controlled under 10 CFU/mL, BOD under 10mg/L, turbidity within 2.0∼2.5 (NTU), and color within 10.3∼13.7 degree. The recycled water is almost colorless and odorless, and is capable of reaching the reference standard for recycled water.
Lake Constance - a model for integrated lake restoration with international cooperation
Authors: Müller H. 
Published: May 2018

Lake Constance is the second largest prealpine European lake. Its international catchment area lies in the territories of the four European countries Austria, Germany, Liechtenstein and Switzerland. Since the fifties, a significant degradation of its state was observed as a result of the pollutants of more than 1.2 million inhabitants in its catchment area. To counteract this negative development, international cooperation was realized in the International Commission for the Protection of Lake Constance (IGKB). Thereby the phosphorus concentration in the lake water, after a maximum value of 87 mg/m3 phosphorus in 1979, was reduced to 13 mg/m3 until 2001. To prevent the negative effects of unfavourable climatic conditions resulting in an incomplete vertical circulation, the concentration of phosphorus must be reduced to 10 mg/m3.
Crucial points in future are to sustain the present successes in lake protection, to reduce existing loads as much as possible, to compensate for loads which are not avoidable and to avoid future loads. A sustainable use of the lake is ensured only by an intact lake ecosystem.
Derivation of a salinity target for the Lower Murray Darling Valley
Authors: Maini N. , Buchan A. , Joseph S. 
Published: May 2018

The NSW Government commissioned catchment management boards (CMBs) to set the direction and process for catchment scale natural resource management. In the Lower Murray Darling, Rivers are highly regulated and water resources shared between three states. The Catchment Board only has jurisdiction over the northern bank of the Murray but salt and water enter the river from many locations upstream and along the area boundary. River salt and flow modelling has continually been improved to reflect and contribute to an increased understanding of salinity processes. The MDBC Salt Load study correlates 10 years of actual measured data with its modelled outputs, and estimates river salinities for 2020, 2050 and 2100. Routing models such as SALTFLO and MURKEY generate percentile salinity levels at different nodes in the River Murray downstream of the Lower Darling confluence.
National, Murray-Darling Basin and NSW salinity management policy and legislative requirements were considered, MDBC model output was used to ensure the interim targets are achievable, auditable, and appropriate to the catchment.
The method for an end-of-valley river based target for salinity is described. A target of less than 463 μS/cm for Lock 6, a point in the lower reaches of the Murray River is recommended for year 2010. Catchment management targets that express the main river salinity risk in five hydrologically distinct management zones are also recommended. Salinity management changes are needed in each zone to meet the end-of-valley target.
The effect of low sludge age on wastewater fractionation (SS, SI)
Authors: Haider S. , Svardal K. , Vanrolleghem P.A. , Kroiss H. 
Published: May 2018

In lab-scale experiments at the 2-stage activated sludge pilot plant of Vienna's central WWTP it is shown that the wastewater soluble COD concentration, which is inert to a sludge with SRT &lt; 1 d (SIA) is about double compared to the SI concentration in sludge with SRT &gt; 10 d (SIB). Unexpectedly the ratio of SIA/SIB is independent of the sludge age between SRTs of 0.4 and 1.0 days. The difference between the two SI fractions is soluble COD that is readily biodegradable by the sludge with SRT &gt; 10 d. However, it is degraded at a lower maximum growth rate. These results comply with earlier results gained with different methods and at different WWTPs. It is hypothesised that very low sludge ages result in a selection of fast growing bacteria, which can utilise only part of the SS in the raw wastewater. The other part of SS therefore remains in the wastewater and can thus be utilised for enhanced denitrification in the second stage.
It is still unknown beyond which sludge age the soluble inert COD SIA starts to decrease, finally reaching the value SIB for low loaded systems (SRT &gt; 5 days). From this point on SI and SS are assumed only to depend on the wastewater composition and not on the sludge age. The assumption of the Activated Sludge Model No.1 that the biodegradable fractions can be modelled as a single substrate and by a single removal kinetic (one Monod term) appears not to be applicable for low sludge ages. Some suggestions for mathematical modelling, design and operation of 2-stage activated sludge systems are given.
Aral Sea and sustainable development
Authors: Usmanova R.M. 
Published: May 2018

Until 1960 the Aral Sea was considered the 4th largest lake in the world by surface area. The Aral Sea has two main inflows - the Amudarya and Syrdarya rivers with about 30 tributaries. From early 1960s because of extensive water use - unreturned withdrawal of water for irrigation and consequent drying up of many tributaries before reaching the main rivers - the water level in the Aral Sea began falling very rapidly. In 1965 the Aral Sea received about 56 cubic km of fresh water yearly, but this number fell to zero by the early 1980s.
By 1990 the level of the Aral Sea water fell by more than 17 m, the volume of water decreased by 75%, the salinity of seawater increased up to 30 g/l, and the surface area of the sea reduced from 66,400 sq. km to 31,500 sq. km.
The ecological situation in Aral Sea zone has became very dramatic. It has led to the changing of climate in the region, irrigated soils becoming deserts, deterioration of underground and surface water quality, reducing of available water for domestic and agricultural needs, loss of Aral Sea fishing and transportation importance, numerous other problems and finally put the health of present and future generations under threat.
This situation not only does not promote further development of the economy of the region, but has also caused damage with irreparable negative consequences. The fact is that the basis of the regional economy is fishing and other associated businesses. Since Uzbekistan is most agricultural country its economy has serious complications. In order to prevent further deepening of this catastrophe and to improve the present situation in this area the Government of the Republic of Uzbekistan has developed a series of measures: in particular it developed efficient water use schemes, changing the cotton situation (that during the Soviet period was grown as monoculture) by planting less water-consuming varieties, reviewing using of fertilizers in agriculture etc. The Aral Sea drought became an international disaster. World Bank, UNESCO, BMBF and others attacked the problem to protect the Aral Sea.
Changes in water quality parameters due to in-sewer processes
Authors: Boxall J. , Shepherd W. , Guymer I. , Fox K. 
Published: May 2018

Combined sewer systems contain a large number of organic and inorganic pollutants from both domestic and industrial sources. These pollutants are often retained within the combined sewer system for significant lengths of time before entering sewage treatment works, or being spilt to a watercourse via a combined sewer overflow (CSO) during storm conditions. Currently little knowledge exists concerning the effects of in sewer processes on pollutants. Understanding of in-sewer processes is important for the effective and efficient design of treatment works and CSO chambers and for impact assessments on receiving waters.
A series of studies covering storm and dry weather flow conditions were undertaken with the aim of investigating the nature of in-sewer processes. These studies consisted of marking a body of water with a fluorescent tracer. The tracer was then monitored at a series of downstream sites, and discrete samples collected from the body of water as it progressed through the sewer. The samples were analysed for water quality parameters and these results investigated in tandem with the detailed hydraulic information gained through the tracer studies. The results highlight the hydraulic differences between storm and dry weather conditions such as increased travel times and mixing under storm conditions. The Advection Dispersion Equation (ADE) and Aggregated Dead Zone (ADZ) model parameters have been quantified for the tracer data. The ADE mixing coefficient is shown to increase by an order of magnitude for storm conditions. The ADZ dispersive fraction parameter is shown to be approximately constant with flow. Chemical reactions and decay within the sewer system were found to be consistent with oxygen limitation.