bluuebunny/crossref_metadata_2025 huggingface dataset:
Anaerobic treatment of slaughterhouse residues in municipal digesters
Authors: Rosenwinkel K.-H. , Meyer H.
Published: May 2018

The tendency to increase the number of units processed per day at slaughter yards (up to 8000 hogs daily), as well as new regulations (recycling and waste laws) in Germany, necessitate extensive utilisation of the residuals coming from slaughter yard operations. Anaerobic digestion appears to be an ideal use for the wet pasty residuals, that have little structure and a water content greater than 70%. The anaerobic digestion of sludges from municipal treatment plants in digesters, has been recognized as the state of the art process for decades. Due to changes in regulations (demands on nitrogen elimination), many digesters still have excess capacities, that allow the co-treatment of additional residuals (cosubstrate). Since little experience has been gained in co-treatment of slaughter waste in municipal digesters, a pilot plant was operated to simulate the process before planning large scale operation. This paper presents the results of the pilot plant, as well as the first months of the co-treatment of stomach contents and slaughter flotation tailings in a municipal digester.
Overview of wastewater treatment and recycling in the textile processing industry
Authors: Rott U. , Minke R.
Published: May 2018

The main aim of this paper is to give a review on the state of the art of available processes for the advanced treatment of wastewater from a Textile Processing Industry (TPI). After an introduction to the specific wastewater situation of the TPI the paper reviews the options of process and production integrated measures. The available unit processes and examples of applied combinations of unit processes are described. A special place is given to the in-plant treatment, the reuse of the treated split flow or mixed wastewater and the recovery of textile auxiliaries and dyes. As a conclusion the paper gives some examples of applied and effective end-of-pipe-steps.
Treatability of textile dye-bath effluents by advanced oxidation: preparation for reuse
Authors: Ince N. H. , Tezcanlı G.
Published: May 2018

Treatability of textile dye-bath effluents by advanced oxidation with Fenton and Fenton-like reagents (FeII/H2O2 and FeIII/H2O2), in the presence and absence of UV light was investigated, using a reactive azo-dye (Procion Red HE7B), and typical dye bath constituents. Under the experimental conditions employed, it was found that with 20 min UV irradiation, complete color removal and 79% total organic carbon degradation is possible, when the system is operated at pH=3, and with a H2O2/Fe(II) molar ratio of 20:1. The increased dissolved solids content of the treated solution implies the necessity of an appropriate membrane system to make the effluent reusable in the dye/wash processes.
Biological phosphorus and nitrogen removal in a full scale sequencing batch reactor treating piggery wastewater
Authors: Tilche A. , Bacilieri E. , Bortone G. , Malaspina F. , Piccinini S. , Stante L.
Published: May 2018

Research activities carried out at ENEA during the last few years allowed the development of a Sequencing Batch Reactor (SBR) that is able to remove biologically organic waste, nitrogen and phosphorus and that was shown to be particularly suited to obtaining low effluent nutrient concentrations even starting from concentrated wastes. Research on optimisation of time cycles and on process modelling, allowed an advanced comprehension of reactor behaviour and the development of a process able to obtain more than 98% removal of nitrogen, phosphorus and COD, and therefore almost capable of matching effluent standards with a sole biological process.

On the basis of laboratory results and process modelling, a full scale SBR plant has been designed and realised. This plant, in ten months of operation, is achieving even better results compared to the laboratory ones.
The development of biological methods for utilisation and treatment of diluted manure streams
Authors: Kalyuzhnyi S. , Sklyar V. , Fedorovich V. , Kovalev A. , Nozhevnikova A. , Klapwijk A.
Published: May 2018

One possible solution for sustainable utilisation and treatment of diluted manure streams is preliminary separation of the solid and liquid fractions followed by separate biological treatment of both fractions. This approach was the starting point of a joint Russian-Dutch project: “The Development of Biotechnological Methods for Utilisation and Treatment of Diluted Manure Streams” (1996-1998). This paper describes the most important results of the project. The UASB process was found to be suitable for the pre-treatment of the liquid fraction of various types of manure using a lab-scale experimental set-up. The maximum organic loading rate (OLR) applied was approximately 12 g COD/1/day for hen or pig manure and 6 g COD/1/day for cattle manure using a hydraulic retention time (HRT) of about 1 day. The total COD reduction under these conditions was about 75% for the hen or pig manure and 42% for the cattle manure. The effluents obtained in this step can be used as liquid fertilisers (if possible) or should be post-treated to meet standards for discharge or reuse. Intensive composting can efficiently treat the solid manure fraction. Experiments at a pilot scale level with the solid fraction of hen manure showed that various amendments (peat, straw, sawdust) could be used for the production of composts having an elevated NPK content, reduced levels of Clostridia and faecal coliforms, vital weed seeds and the absence of Salmonella and helminth eggs.
Improvement of anaerobic treatment of tannery beamhouse wastewater by an integrated sulphide elimination process
Authors: Schenk H. , Wiemann M. , Hegemann W.
Published: May 2018

Sulphide, and especially the undissociated form, hydrogen sulphide, is inhibitory to anaerobic wastewater treatment processes. Tannery beamhouse wastewater contains high concentrations of organic material which make an anaerobic treatment favourable, but it also contains high concentrations of sulphide which cause difficulties for anaerobic treatment. The success of an anaerobic treatment will depend on reliable elimination of the sulphide. In batch tests stripping was the most effective process for sulphide removal compared to precipitation. The chemical-physical COD removal caused by the stripping was negligible, while precipitation caused a COD-removal of 26%. Also, anaerobic degradation velocity was higher if sulphide was removed by stripping. In fixed bed reactors operated continuously, stripping was shown to be a reliable method for eliminating hydrogen sulphide toxicity. Hydrogen sulphide caused an inhibition of 0.2% per mg 1−1 for methanogenic bacteria. Acidogenic bacteria were not inhibited by hydrogen sulphide. The gas-liquid equilibrium was shown to deviate from theoretical values taken from literature.
Two-phase anaerobic treatment of cheese whey
Authors: Yılmazer Gülüm , Yenigün Orhan
Published: May 2018

Performance of two-phase anaerobic digestion of cheese whey was investigated in a system consisting of a continuous stirred tank reactor (CSTR) as the acidogenic reactor and an upflow anaerobic filter (UFAF) as the methanogenic reactor. The acidogenic reactor was operated at various hydraulic retention times (HRTs) between 18 hours and 4 days. The results showed that an optimum HRT for the acidogenic reactor with the same organic loading rate (OLR) between 0.5-2 g COD/MLSS day was 24 hours. At this retention time the acidification rate increased up to a maximum of 50%. Volatile fatty acids (VFAs) produced in the acidogenic reactor operating at an HRT of 24 hours were 52% acetic acid, with 14% propionic, 27% butyric and 7% isovaleric acids. Operating the acidogenic reactor at this HRT, the effluent was fed to the upflow anaerobic filter. Here HRT was varied between 3-6 days for the best COD removal efficiency and biogas production. At an HRT of 4 days a 90% soluble effluent COD removal efficiency was obtained with an outmost biogas yield of 0.55 m3/kg COD removed.
Anaerobic treatment of potato processing wastewater
Authors: Zoutberg George R. , Eker Zerrin
Published: May 2018

This paper deals with the anaerobic treatment of wastewater from the potato processing industry. It is shown that treatment of this type of wastewater in UASB reactors has successfully been applied at many companies. Apart from the Biothane® UASB technology a new anaerobic technology is presented: the Biobed® EGSB technology. Presented is the first application of this technology in the potato processing industry and also a comparison is made between this technology and the Biothane® UASB technology.
Full scale experiences with anaerobic/aerobic treatment plants in the food and beverage industry
Authors: Austermann-Haun U. , Meyer H. , Seyfried C. F. , Rosenwinkel K.-H.
Published: May 2018

In Germany, there are currently 125 full-scale anaerobic treatment plants treating industrial wastewater. This paper describes the operational experiences of several industries (beet sugar, starch, pectin brewery, distillery, vegetable, potato processing) which undertake anaerobic wastewater treatment, with particular emphasis on specific wastewater problems and their solutions. Also presented are experiences with the handling of high nitrate concentrations, with the treatment of mixtures of industrial wastewater from different origins, with the chance to prevent the emergence of lime, magnesium ammonium phosphate (MAP) or aluminium precipitation. This paper deals as well with the first EGSB reactor (Expanded Granular Sludge Bed) at a German potato processing factory as well as the first municipal wastewater treatment plant combined with a separate anaerobic stage to treat a wastewater mixture from several small factories.
Integrated treatment of olive oil mill effluents: effect of chemical and physical pretreatment on anaerobic treatability
Authors: Beccari M. , Majone M. , Riccardi C. , Savarese F. , Torrisi L.
Published: May 2018

Difficulties met in the anaerobic treatment of olive oil mill effluents (OME) suggest the use of a chemico-physical pretreatment for the removal of biorecalcitrant and/or inhibiting substances (essentially lipids and polyphenols) as selectively as possible before anaerobic digestion. Laboratory scale experiments were carried out in order to identify pretreatment type and conditions capable of optimizing OME anaerobic digestion in terms both of kinetics and methane yield. Ultrafiltration, even if it allowed very high removals of lipids and polyphenols, was affected by poor selectivity (indeed, large amounts of biodegradable COD were also removed). Centrifugation turned out to be preferable to sedimentation owing to smaller volumes of separated phase. Results of great significance were obtained by adding Ca(OH)2 (up to pH 6.5) and 15 g/l of bentonite, and then feeding the mixture to the biological treatment without providing an intermediate phase separation. Indeed, the biodegradable matter adsorbed on the surface of bentonite was gradually released during the biotreatability test, thus allowing the same methane yield (referred to the total COD contained in untreated OME) both in scarsely diluted (1 : 1.5) pretreated OME and in very diluted (1 : 12) untreated OME. Application of a continuous process combining pretreatment (with Ca(OH)2 and bentonite) and anaerobic digestion without intermediate phase separation is suggested.
Contribution of southern fruit peels to the contamination of biological waste
Authors: Förster M. , Vorkamp K. , Taube J. , Herrmann R.
Published: May 2018

The aim of this study was to estimate the pesticide contamination of biological waste caused by the peels of southern fruits. For this reason 105 samples of southern fruit peels were analysed for 18 different pesticides. Pesticide residues were found in all peels. The pesticides found most frequently and in the highest concentrations were the fungicides thiabendazole and ortho-phenyl-phenol. The peels of citrus fruits generally contained higher pesticide concentrations than those of bananas and kiwis. Based on these findings the pesticide contamination of German biological waste caused by southern fruit peels was estimated. Also, the influence of the four main pesticides on the microbial gas production in the acidogenic phase of biological waste fermentation was investigated by means of simple batch-assays. Ortho-phenyl-phenol was the only pesticide that irreversibly inhibited the gas production, but only in concentrations which exceeded those expected in biological waste by several orders of magnitude.
Waste management in Hong Kong abattoirs
Authors: Koenig A. , Yiu W. C.
Published: May 2018

This paper reports the results of an extensive investigation on the waste management in Hong Kong abattoirs with the following objectives: (i) to identify the existing waste management practices in relation to sources and quantity of wastes generated, methods of storage and handling of wastes, any in-house treatment, and final disposal of wastes, (ii) to identify the problems of existing waste management practices, and (iii) to evaluate the future development. To obtain up-to-date data and reliable information, site visits were conducted and the management of the abattoirs were interviewed in detail about the operation and waste management practices. For each abattoir and one associated by-product plant, detailed material balances were established for liquid and solid wastes. Complete quantitative results on waste loads, water consumption and material/waste flows are presented. Operational problems regarding wastewater treatment, as well as waste reduction and potential for reuse or recycle of solid wastes are discussed in the context of Hong Kong. Finally, information on the proposed new slaughterhouse (design capacity 5000 pigs and 400 cattle daily) is provided which will include a novel underground wastewater treatment plant.
Experimental investigation on the efficiency of a high side weir overflow
Authors: Luyckx Gert , Vaes Guido , Berlamont Jean
Published: May 2018

Most of the overflow structures in Flanders are ‘high side weir overflows’. For the design of these structures British guidelines are used. However, the design conditions for sewer systems in the U.K. differ from the Flemish design conditions. In Flanders, pressurised flow is in common use in the pipes of the sewer system. That is why tests have been carried out on a scale model of a high side weir overflow. The optimal dimensions are determined, using different model sediments. Also efficiency relationships have been determined. For a particular chamber geometry and particular flow conditions, the efficiency of a certain sediment fraction is only determined by the settling velocity of this fraction.
Preferential solute movement along the interface of soil horizons
Authors: Kamra S. K. , Michaelsen J. , Wichtmann W. , Widmoser P.
Published: May 2018

Preferential flow significantly contributes to groundwater contamination due to rapid bypass of large fractions of applied agrochemicals through the vadose zone. Transport of surface-applied non-reactive tracer (bromide) and pesticides was studied from 1991/92 to 1994/95 in an experimental drain plot in northern Germany. The soil of the study site was sandy loam in texture with high bulk density and a distinct structural change from sub-angular to angular at the interface of two soil horizons at 30-40 cm. Each year, bromide and pesticides appeared in drain water with the first drainage event followed by steep concentration peaks indicating preferential solute movement. The general shape of the breakthrough curves, magnitude and time of occurrence of the main concentration peaks of bromide and pesticides were comparable in different years despite notable differences in rainfall, drain discharge and areas of chemical application. Further, it was observed that variable drain discharges occurred without significant changes in water table levels, and a major fraction of surface-applied bromide and pesticides appeared in drainage effluent without apparently leaching through the deeper layers. It appears that water and solutes, after vertical movement through the upper plough layer, moved horizontally along the interface of two soil horizons towards and through the porous drain trench to the drain.
Study of transport of contaminants in a pipe network using the model EPANET
Authors: Ratnayake Niranjanie , Jayatilake Indunil N.
Published: May 2018

A rural water supply system having two probable water sources, with an elevated tank, required to serve three schools and a hospital, was selected for this study. The model EPANET was used to study the variation of concentrations within the network of conservative and non-conservative substances introduced into the water at the source node and at other nodes. This paper discusses the findings of four scenario analyses undertaken in order to study the behaviour of the contaminants, and to develop strategies for management of some difficult situations encountered in water supply schemes. In the two source supply situation, it was observed that the water quality at the critical points in the system could be maintained below the permissible fluoride concentration, while maintaining the water requirements, by changing the pump operation cycles. When the behaviour of residual chlorine in the system was studied, it was observed that the model can be used to discover the chlorine booster points to maintain the required minimum residual chlorine content at the distribution terminal points. The results need to be verified by field-testing, once the water supply scheme, which is still under construction, is commissioned.
Seasonal size distributions of suspended solids in a stormwater management pond
Authors: Krishnappan B. G. , Marsalek J. , Watt W. E. , Anderson B. C.
Published: May 2018

Three seasonal surveys of suspended solids were carried out in an on-stream stormwater management pond, by means of a submersible laser particle size analyser. Size distributions were measured at up to 17 points in the pond, and water samples collected at the same locations were analysed for primary particles aggregated in flocs. Observed suspended solids were mostly composed of flocs, with maximum sizes ranging from 30 to 212 μm for winter and summer surveys, respectively. Using a relationship defining the floc density as a function of floc size and Stokes' equation for settling, an empirical relationship expressing the floc fall velocity as a function of floc size was produced. This relationship indicates that naturally formed flocs in the size range from 5 to 15 μm would settle faster than both smaller primary particles of higher density, and somewhat larger flocs of lower density, which are however susceptible to break up by turbulence.
Improved interception of combined sewage in the Trondheim-Høvringen wastewater system
Authors: Milina J. , Sægrov S. , Lei J. , König A. , Nilssen O. , Ellingsson A. , Alex J. , Schilling W.
Published: May 2018

This paper describes some results of an integrated model development and its application to the Høvringen wastewater system in Trondheim, Norway. Major model development needs concern the integration of sewage production, transport and treatment simulation, the interface with existing databases and the possibility of simulating processes that are controlled in real time. The developed integrated model has been used to design the treatment process as well as static and dynamic measures in both the catchment and the sewer system. These measures include extended pumping, adjustment of overflows, separation of storm water runoff from “non-effective separate systems”, retention and real-time control of the sewer tunnel volume.
Assessing groundwater vulnerability to agrichemical contamination in the Midwest US
Authors: Burkart Michael R. , Kolpin Dana W. , James David E.
Published: May 2018

Agrichemicals (herbicides and nitrate) are significant sources of diffuse pollution to groundwater. Indirect methods are needed to assess the potential for groundwater contamination by diffuse sources because groundwater monitoring is too costly to adequately define the geographic extent of contamination at a regional or national scale. This paper presents examples of the application of statistical, overlay and index, and process-based modeling methods for groundwater vulnerability assessments to a variety of data from the Midwest U.S. The principles for vulnerability assessment include both intrinsic (pedologic, climatologic, and hydrogeologic factors) and specific (contaminant and other anthropogenic factors) vulnerability of a location. Statistical methods use the frequency of contaminant occurrence, contaminant concentration, or contamination probability as a response variable. Statistical assessments are useful for defining the relations among explanatory and response variables whether they define intrinsic or specific vulnerability. Multivariate statistical analyses are useful for ranking variables critical to estimating water quality responses of interest. Overlay and index methods involve intersecting maps of intrinsic and specific vulnerability properties and indexing the variables by applying appropriate weights. Deterministic models use process-based equations to simulate contaminant transport and are distinguished from the other methods in their potential to predict contaminant transport in both space and time. An example of a one-dimensional leaching model linked to a geographic information system (GIS) to define a regional metamodel for contamination in the Midwest is included.
Water resources of the Texas Gulf Basin
Authors: Arnold J. G. , Srinivasan R. , Ramanarayanan T. S. , DiLuzio M.
Published: May 2018

A geographic information system (GIS) has been integrated with a distributed parameter, continuous time, nonpoint source pollution model SWAT (Soil and Water Assessment Tool) for the management of water resources. This integration has proven to be effective and efficient for data collection and to visualize and analyze the input and output of simulation models. The SWAT-GIS system is being used to model the hydrology of eighteen major river systems in the United States (HUMUS). This paper focuses on the integration of SWAT (basin scale hydrologic model) with the Geographical Resources Analysis Support System (GRASS-GIS) and a relational database management system. The system is then applied to the Texas Gulf River basin. Input data layers (soils, land use, and elevation) were collected at a scale of 1:250,000 from various sources. Average monthly simulated and observed stream flow records from 1970-1979 are presented for the hydrologic cataloging units (HCU) defined by the United States Geological Survey (USGS) in the Texas Gulf basin. Average annual sediment yields computed from sediment rating curves are compared against simulated sediment yields from seven river basins within the Texas Gulf showing reasonable agreement.
Substratum Phosphorus Accumulation during Maturation of Gravel-bed Constructed Wetlands
Authors: Tanner C. C. , Sukias J. P. S. , Upsdell M. P.
Published: May 2018

Accumulation of phosphorus was investigated in the substrata and surface deposits of pilot-scale gravel-bed constructed wetlands after 2 (planted and unplanted) and 5 (planted only) years operation. Four different hydraulic loading rates of farm dairy wastewaters provided mean cumulative total P (TP) loadings ranging from ∼520 to 2000 g m−2 after 5 years operation. Mean substratum TP accumulations after 2 years operation ranged from 52 to 100 g m−2 in the planted wetlands and from 40 to 51g m−2 in the unplanted wetlands, both showing a general increase with wastewater loading. After 5 years operation, associated with declining wetland TP removal performance, substratum TP accumulations in all the planted wetlands converged at similar values of 115 to 128 g m−2. This represented 6 to 23% of their cumulative loadings.
Treatment of Potato Processing Wastewater with Engineered Natural Systems
Authors: Burgoon Peter S. , Kadlec Robert H. , Henderson Mike
Published: May 2018

A full-scale integrated natural system has been used to treat high strength potato processing water for 2 years. The integrated natural system consists of free water surface and vertical flow wetlands, and a facultative storage lagoon. Influent wastewater averages 2800 mg/L COD, 150 mg/L TN and 350 mg/L TSS. Approximately 5300 m3/d of wastewater flows through the treatment system annually. The treatment objective is a 53% reduction in total nitrogen. The wastewater application permit requires an annual nitrogen load of 500 kg/ha yr on 213 hectares of land used to grow alfalfa and other fodder crops. Free water surface wetlands are used for sedimentation, mineralization of organic matter, and denitrification. Vertical flow wetlands oxidize organic matter and nitrogen. A lagoon provides storage during the winter when irrigation is not possible and functions as a facultative lagoon. Free water surface wetlands were planted with Typha latifolia and Scirpus validus in fall 1995. Wastewater application began in July of 1996. In the summer months COD removal has been greater than 95% through the free water surface wetlands and vertical flow wetlands. The removal rate decreased to about 75% in the winter. Average summer water temperatures are 18°C; average winter water temperatures are 3°C. Ammonia removal through the vertical flow wetlands averages 85% during the summer and 30-50% removal during the winter. Addition of exogenous carbon to the free water surface wetlands resulted in 95% removal of NO3-N. Use of natural systems have proved to be a cost effective treatment alternative for high strength industrial wastewater.
Design Recommendations for Subsurface Flow Constructed Wetlands for Nitrification and Denitrification
Authors: Platzer Christoph
Published: May 2018

The paper presents a design for nitrogen removal in subsurface flow wetlands. The nitrification in the vertical-flow beds (VFBs) is clearly determined by the oxygen balance in the filter. Full nitrification can only be achieved when the oxygen balance is positive. For sizing purposes equations for the calculation of oxygen demand and oxygen input are given. Three possibilities to achieve sufficient soil aeration are presented and explained.

For the denitrification two possibilities are presented. From technical wastewater treatment plants predenitrification is well known. Return rates up to 200% can be used without hydraulic problems for the VFBs. In cases of low C/N ratios an additional application of HFBs has to be used. The design can be carried out using a design of 1 g NO3-N/m2,d achieving a 65% removal in more than 90% of the cases.

The paper discusses some of the equations presented internationally. The suitability of the use of k-values for the processes nitrification and denitrification is especially questioned.
Removal Efficiency of Three Cold-Climate Constructed Wetlands Treating Domestic Wastewater: Effects of Temperature, Seasons, Loading Rates and Input Concentrations
Authors: Mæhlum Trond , Stålnacke Per
Published: May 2018

This paper outlines the influence of temperature, flow rate and input concentrations on the treatment efficiency of organic matter and nutrients in constructed wetlands (CWs). Three integrated 10 PE systems with horizontal subsurface flow (HSF) treating domestic wastewater are described. Particular attention is devoted to: (1) aerobic pre-treatment in vertical-flow filters, (2) filter media with high phosphorus (P) sorption capacity, and (3) the treatment efficiency during winters. Aerobic pre-treatment followed by CW units including P sorption media removed most organic matter (BOD> 75%), P (> 90%) and total and ammonia N (40-80%). P retention was relatively stable in wetland filters, both with lightweight aggregates and ferruginous sand during 3-6 years of monitoring. Iron-rich sand from Bsh and Bs horizons of ferro-humic podzols was efficient for P sorption, but removal efficiencies of COD, TOC and SS were negative. The differences in efficiency between cold and warm periods were less than 10 percentage points for all parameters. It is anticipated that temperature effects are partially compensated by the large hydraulic retention time. The findings suggest that HSF systems do not require vegetation.
Design of a Hybrid Reed Bed System to Achieve Complete Nitrification and Denitrification of Domestic Sewage
Authors: Cooper Paul , Griffin Paul , Humphries Stuart , Pound Adrian
Published: May 2018

The design of vertical-flow (VF) reed beds is reviewed and the performance of the few worldwide existing hybrid systems, combining both horizontal- and vertical-flow beds, is assessed. Horizontal-flow (HF) beds are good for suspended solids removal and will remove BOD5 up to a set loading. Vertical-flow beds can achieve BOD5 removal at much higher loading rates and they are capable of complete nitrification as tertiary or secondary treatment systems. It is possible to achieve biological denitrification in horizontal-flow beds. By combining horizontal- and vertical-flow systems in the appropriate process sequence it is thus possible to produce a system which removes BOD5, TSS and achieves complete nitrification as well as substantial removal of nitrate and hence a lowered Total N.

The paper discusses the possible process options for combining horizontal- and vertical-flow systems. One example of these systems will be described in more detail. This is a flexible hybrid system being built by Severn Trent Water. Designed to treat the flow for a small village with a population of 129 it will have vertical-flow beds followed by horizontal-flow beds. The design allows for flexibility such that the size of the vertical-flow and horizontal-flow stages can be altered (for experimental purposes) to allow the design arrangement to be stressed and performance evaluated with the intention of defining the optimum loading rates for each of the stages.

The same site also has sludge drying reed beds for treating the primary sludge.
Nutrient Sinks in a Constructed Melaleuca Wetland Receiving Secondary Treated Effluent
Authors: Bolton Keith G. E. , Greenway Margaret
Published: May 2018

This study examined N, P and K partitioning in the sinks of a 130 m2 constructed Melaleuca wetland after receiving secondary treated sewage effluent for 21 months. The sinks examined were: 1) biomass, which was further partitioned into the harvestable above ground portion and the roots; 2) sediment; 3) gravel and; 4) the clay base. Gravel was the major nutrient storage sink, however this was a function of the high gravel particle mass (525 kg m−2) rather than high nutrient concentrations. M. alternifolia trees had the highest biomass due to high growth rates, higher planting densities, and low litterfall. M. quinquenervia trees were severely attacked by a sap sucking Heteropteron (Eucerocoris. suspectus) which stunted growth, but resulted in a cumulative litterfall mass three times that of the M. alternifolia trees. The sediment sink was strongly influenced by litterfall, with the sediment sink in the M. quinquenervia terraces storing more than twice the nutrients in the sediment sink of the M. alternifolia terraces. Because of their higher grwoth rates and above ground biomass fraction, and their potential to produce tea tree oil, M. alternifolia is most suitable for constructed wetlands incorporating a harvesting regime. Because of their high rate of transfer from the biomass to sediment sink via litterfall, M. quinquenervia is more suited to non-harvested constructed wetlands.
Coping with ever larger problems, models, and data bases
Authors: Beck M. B.
Published: May 2018

Those who construct models, including models of the quality of the aquatic environment, are driven largely by the search for (theoretical) completeness in the products of their efforts. For if we know of something of potential relevance, and computational power is increasing, why should that something be left out? Those who use the results of such models are probably reassured by this imprimatur, of having supposedly based their decisions on the best available scientific evidence. Our models, and certainly those we would label “state-of-the-art”, seem destined always to get larger. Some observations on possible strategies for coping with this largeness, while yet making well reasoned and adequately buttressed decisions on how to manage the water environment, are the subject of this paper. Because it is so obvious, and because it has been the foundation of analytical enquiry for such a very long time, our point of departure is the classical procedure of disassembling the whole into its parts with subsequent re-assembly of the resulting part solutions into an overall solution. This continues to serve us well, at least in terms of pragmatic decision-making, but perhaps not in terms of reconciling the model with the field observations, i.e., in terms of model calibration. If the indivisible whole is to be addressed, and it is large, contemporary studies show that we shall have to shed an attachment to locating the single, best decision and be satisfied instead with having identified a multiplicity of acceptably good possibilities. If, in the face of an inevitable uncertainty, there is then a concern for reassurance regarding the robustness of a specific course of action (chosen from among the good possibilities), significant recent advances in the methods of global (as opposed to local) sensitivity analysis are indeed timely. Ultimately, however, no matter how large and seemingly complete the model, whether we trust its output is a very strong function of whether this outcome tallies with our mental image of the given system's behaviour. The paper argues that largeness must therefore be pruned through the application of appropriate methods of model simplification, through procedures aimed directly at this issue of promoting the generation, corroboration, and refutation of high-level conceptual insights and understanding. The paper closes with a brief discussion of two aspects of the role of field observations in evaluating a (large) model: quality assurance of that model in the absence of any data; and the previously somewhat under-estimated challenge of reconciling large models with high-volume data sets.
Modelling of water quality-based emission limits for industrial discharges in rivers
Authors: Ragas A. M. J. , Leuven R. S. E. W.
Published: May 2018

Water authorities apply a diversity of models and input data to set water quality-based emission limits in discharge permits. To illustrate the consequences of model and data selection, two complete mixing models and four mixing zone models used in Germany, the United Kingdom (UK), the Netherlands and the United States of America (USA) were selected and applied to various discharges of cadmium. The maximum allowable annual cadmium load was calculated for each model and diverging input data for upstream flow, upstream concentration, effluent flow and effluent concentration. Due to model selection, differences in pollutant loads amounted to a factor 3. Harmonisation of the derivation of water quality-based emission limits is necessary to prevent widely divergent pollutant loads under comparable environmental conditions.
Setting up measuring campaigns for integrated wastewater modelling
Authors: Vanrolleghem Peter A. , Schilling Wolfgang , Rauch Wolfgang , Krebs Peter , Aalderink Hans
Published: May 2018

The steps of calibration/confirmation of models in a suggested 11-step procedure for analysis, planning and implementation of integrated urban wastewater management systems is focused upon in this paper. Based on ample experience obtained in comprehensive investigations throughout Europe recommendations have been formulated for design of measuring campaigns. The inclusion of iteration in the overall planning of measuring campaigns is advised and the use of preliminary sensitivity analysis is shown to allow maximisation of information retrieval from experimental efforts. Case studies covering problems related to suspended solids, specific contaminants, hygienic hazards and total pollutant loss illustrate the recommendations presented.
Collected rainfall as a water source in Danish households - what is the potential and what are the costs?
Authors: Mikkelsen P. S. , Adeler O. F. , Albrechtsen H.-J. , Henze M.
Published: May 2018

The water resource, energy and economy aspects of rainwater collection are assessed to evaluate rainfall collection as an alternative option for sustainable water supply. A maximum of 229 million m3/year of rainwater can be collected from Danish roofs, provided that all possible surfaces are used and all rain falling on the surfaces is collected. This is equivalent to 24% of the total present production of drinking water, which is mainly based on groundwater. From household roofs 64.5 million m3/year can be collected if used for toilet flushing and washing of clothes. This is 68% of the actual demand for toilet flushing and washing of clothes in households and 22% of the total water consumption in households, but only 7% of the total present drinking water production in Denmark. From the society point of view there is neither an environmental nor an economic reason to systematically promote rainfall collection on a larger scale in Denmark. Thus it is important to see rainfall collection in a local context, and in each case to evaluate whether there are cheaper alternative water sources or options for minimising the water consumption.
Use of permeable, reservoir pavement constructions for stormwater treatment and storage for re-use
Authors: Pratt C. J.
Published: May 2018

Permeable surfaces for roads and footpaths have been used as a means of disposal of stormwater in developed urban areas. Such surfaces provide an alternative to impermeable concrete or tarmacadam surfaces which would otherwise produce rapid stormwater runoff, leading to possible flooding and degeneration of receiving water quality through the uncontrolled discharge of polluted urban waters. A further advantage may be obtained from such constructions by undersealing them so as to retain stormwater for re-use for non-potable uses. The potential for general introduction of this type of storage and re-use system in residential areas is discussed and possible alternative designs for the drainage infrastructure proposed. To have widespread impact such a strategy must deliver cost savings as well as reduce the impact on the water environment of anticipated water usage demands. The source of such cost savings and the general environmental benefits of such systems will be presented. The materials used in such a sealed construction and the beneficial changes to the stored water quality are outlined. Recent work has also shown that where the pavement is used for car parking any oils dropped on the surface and washed into the structure by the stormwater may also be degraded. Details will be given of a site in the UK where the above construction is to be used to provide stormwater storage for re-use in flushing toilets at a Youth Hostel.
Difficulties and developments in biological nutrient removal technology and modelling
Authors: Ekama George A. , Wentzel Mark C.
Published: May 2018

Filamentous bulking and the long sludge age required for nitrification are two important factors that limit the wastewater treatment capacity of biological nutrient removal (BNR) activated sludge systems. A growing body of observations from full-scale plants indicate support for the hypothesis that a significant stimulus for filamentous bulking in BNR systems in alternating anoxic-aerobic conditions with the presence of oxidized nitrogen at the transition from anoxic to aerobic. In the DEPHANOX system, nitrification takes place externally allowing sludge age and filamentous bulking to be reduced and increases treatment capacity. Anoxic P uptake is exploited in this system but it appears that this form of biological excess P removal (BEPR) is significantly reduced compared with aerobic P uptake in conventional BNR systems. Developments in the understanding of the BEPR processes of (i) phosphate accumulating organism (PAO) denitrification and anoxic P uptake, (ii) fermentation of influent readily biodegradable (RB)COD and (iii) anaerobic hydrolysis of slowly biodegradable (SB)COD are evaluated in relation to the IAWQ Activated Sludge Model (ASM) No.2. Recent developments in BEPR research do not yet allow a significant improvement to be made to ASM No. 2 that will increase its predictive power and reliability and therefore it remains essentially as a framework to guide further research.
Different mechanisms for the anaerobic storage of organic substrates and their effect on enhanced biological phosphate removal (EBPR)
Authors: Carucci A. , Lindrea K. , Majone M. , Ramadori R.
Published: May 2018

The driving force for Enhanced Biological Phosphorus Removal (EBPR) is the presence of an anaerobic zone that enriches the activated sludge for P-accumulating microorganisms (PAOs). According to accepted models, PAOs anaerobically store volatile fatty acids (VFAs) as polyhydroxyalkanoates (PHAs) utilising polyphosphate hydrolysis as the energy source. For substrates other than VFAs, one hypothesis is that other heterotrophs convert them to VFAs, so acting in favour of PAOs. However, particular glycogen accumulating microorganisms have been described (GAOs), that compete against PAOs being able to store anaerobically many substrates into PHAs, by transforming intracellular carbohydrates (glycogen) into PHAs, as the energy source. In this perspective, the paper presents a summary (with new findings) of a long experimental work to study EBPR processes with a lab-scale Sequencing Batch Reactor fed with different organic substrates (peptone, glucose and acetate, separate or in mixtures). Our results show that EBPR can be obtained with substrates other than VFAs with neither their pre-conversion to VFAs nor their storage as PHA. Moreover, in different periods anaerobic uptake of glucose was possible with and without EBPR. In both cases, the stored polymer was glycogen while the energy source was either polyphosphate hydrolysis or lactic fermentation, respectively. These results are not consistent with the reported behaviour of PAOs or GAOs, so showing that many different mechanisms of anaerobic uptake and storage of substrates can act in favour of, or against EBPR. Deeper insight on these mechanisms is needed to improve design and operation of EBPR plants.
Odorous Compounds in Wastewater Reservoir Used for Irrigation
Authors: Ginzburg B. , Dor I. , Lev O.
Published: May 2018

The objective of this study was to investigate the odor and physicochemical characteristics of a model deep wastewater reservoir (the Na'an reservoir). Depth sampling of the reservoir revealed depletion of oxygen and increase of hydrogen sulfide and organic nitrogen and sulfur odorous compounds at deeper levels of the reservoir. TOC, TON, BOD5 and chromatographic fingerprinting by MSD and Olfactory/GC of the semi-volatile organic compounds in the reservoir were found to be season dependent. Late summer was found to be the most odorous period and the richest in semi-volatile compounds. A list of volatile compounds, which were identified by gas chromatography, in the reservoir water and in the surrounding atmosphere was compiled.
Evaluation of Consumer Attitudes on Taste and Tap Water Alternatives in Québec
Authors: Levallois P. , Grondin J. , Gingras S.
Published: May 2018

A telephone survey carried out in 1995 in the Québec metropolitan area reached 2009 residents of four municipalities. Tap water was consumed regularly by only 50.8 percent of the consumers and bottled water by 42.7 %. Consumer dissatisfaction regarding the quality of tap water was noted. Fourteen percent were dissatisfied with the odor, and 30.6 % with the taste or flavor. Health risks, regarding ingestion of tap water, were mainly not perceived or seen only as a minor issue to consumers.

Multiple regression analysis indicated that knowledge of the source of the water was not a major determinant for selecting alternatives to tap water (e.g., bottled water or use of home treatment devices). Such use of alternatives was in fact six times higher in consumers dissatisfied with the taste of the water (OR = 6.0, p = 0.001) and only 35 % higher if people were connected to a distribution network using the St. Lawrence River as the source of supply (OR = 1.35, p = 0.01). No explanation was given for the taste problem reported.
Development of a Packed Precolumn for Capillary Gas Chromatographic Analysis of Amines in Acidic Aqueous Solution
Authors: Maris Christophe , Laplanche Alain , Morvan Jean , Bloquel Marianne
Published: May 2018

This paper describes an optimization of the analysis of amines in aqueous solution. Direct injection of the acidic sample (HCl 0.12 N) is performed by the coupling of packed precolumn with a capillary column. The basic support efficiently traps residual vapors of hydrochloric acid and water at the injection time; the capillary chromatographic performance is maintained. The precolumn coupling with PoraPLOT Amines capillary column enables a separation and quantification of the lower volatile aliphatic amines (methylamine, dimethylamine, trimethylamine and ethylamine). The ammonia addition to the solution (200 ppm NH3) reduces amine adsorption in the column. The analysis repeatability is about 5% for a 50μM amine mixture and 21% for the quantification limit of 0.5 μM with a sensitive and specific nitrogen phosphor detector. The precolumn avoids using split injection (sensitivity increased). Other nitrogen compounds can be analyzed by this system: aromatic amines (aniline) and unsaturated nitrogen heterocycles (pyridine). This new technique increases the chromatographic performances in comparison with usual methods; its automation is possible.
Improving Odour Detection by Assessors
Authors: MacRae A.W. , Farrimond M. , Hodsoll J. , Falahee M. , Simms J. , Hopper R.
Published: May 2018

In a test of theoretical predictions made by MacRae and Falahee (1995), trained assessors evaluated water samples which sometimes contained 10−5 mg/l of trichloroanisole, using three different procedures. Compared with the blue-book method of single-sample assessment, providing a reference sample identified to the assessor as being odour-free increased the proportion of responses reporting an odour. This decreased the number of odorous samples missed. Although this outcome may be valuable in itself, discrimination between odorous and odour-free samples was not really enhanced since ‘false alarms’ increased correspondingly. Incorporating additional, different odours into the sequence of samples and giving knowledge of results when these were judged, dramatically improved performance - the rates both of missing trichloroanisole and of mistakenly attributing odour to odour-free samples were halved.
Aerobic stabilisation criteria for BNR biosolids
Authors: Tonkovic Zlatko
Published: May 2018

A research program was undertaken to establish the stability of waste activated sludge generated from several activated sludge treatment plants, both nutrient removal and conventional, and determine what further treatment is required to produce a substantially stabilised (ie. non-odorous) sludge.

It has been previously thought that waste activated sludge from extended aeration plants (sludge age of approximately 25 days) was sufficiently stabilised to permit dewatering and stockpiling without odour generation. However, experience at a number of treatment plants with large unaerated mass fractions for biological removal of nitrogen and phosphorus has demonstrated that these sludges are generally odorous. With the increasing requirement for on-site storage of sludge to remove pathogens prior to sludge re-use, odour generation from secondary sludges has the potential to pose significant environmental problems for many treatment plants.

The objective of the research program was to quantify the degree of stabilisation achieved in various activated sludge treatment plants, what additional aerobic treatment is required to achieve a stabilised sludge and what are the readily identified characteristics of a stabilised sludge, including volatile solids content, specific oxygen uptake rate and pathogen destruction. The phosphorus leaching characteristics were also compared between various sludges and between continuous and intermittent aerobic digestion processes.