bluuebunny/crossref_metadata_2025 huggingface dataset:
The application of pinch analysis to water, reagent and effluent management in a chlor-alkali facility
Authors: Gianadda P. , Brouckaert C.J. , Sayer R. , Buckley C.A.
Published: May 2018

South African industry is coming under increasing pressure to reduce the amount of freshwater it uses and the amount of effluent it produces. Water pinch is a cleaner production technique aimed at reducing the freshwater consumption and effluent production within a chemical complex. The design of water-reuse or water pinch networks as applied to the case study of a chlor-alkali complex is considered. Insights are provided into the analysis and formulation of problems for large-scale industrial systems and the application of present techniques and tools to the formulated problem is illustrated. The features of the problem posed by the chlor-alkali facility are discussed and the limitations of the present theory in dealing with this problem highlighted. The concepts of utility-water pinch analysis and process-water pinch analysis are introduced.
Design and implementation of a measuring campaign to model pesticide impacts in an Ecuadorian watershed
Authors: Matamoros D. , Bonini J. , Guzman E. , Ramirez G. , Vanrolleghem P.A.
Published: May 2018

The first important issue in pesticide assessment for a watershed is the availability of soil and water quality information in the form of charts, maps or records. However, developing countries generally do not have enough historical data. Thus, sampling programs are crucial for the success of the evaluation, although in developing countries they always represent a controversial task between limited available budget and a precise assessment. This paper shows the steps taken to generate soil and water data to be used in a pesticide assessment project for a 34,000 ha watershed in Ecuador, South America. Sampling campaigns are still being run, so the methodology and the first results are shown here.
Implementation of best management practices in agriculture: modelling and monitoring of impacts on nitrogen leaching
Authors: Joelsson A. , Kyllmar K.
Published: May 2018

In Kattegat and the coastal water of the Baltic Sea, high nitrogen input from agricultural land is considered to be the main reason for eutrophication. International agreements and governmental programs have set a target to reduce the anthropogenic nitrogen load by 50 percent. Improved nitrogen removal in treatment plants and efforts in agriculture have so far not decreased nitrogen transport to a sufficient extent. In this project the impact of agricultural practices on nitrogen leaching was investigated in two small agricultural catchments in Southwest Sweden. The root-zone leaching was estimated by an indexing technique. Simultaneously the transports in the stream outlets were monitored. During 1995 and 1999 the agricultural practices in the catchments were surveyed. Field data from the first survey indicated that fertilisation did not always match crop requirements, the area of undersown catch crop can be increased and autumn cultivation can be reduced. The second survey was preceded by an advisory campaign where each farmer was visited and presented with an environmental plan including fertilisation, cultivation, and crop rotation for the farm. The plan summarised the best management practices that could be realised under actual conditions. Results from the second survey showed that some changes in the agricultural practices were carried out after the advisory campaign. The nitrogen leaching from the root-zone was then estimated by the indexing technique, both for the time before and after the advisory program. The results showed that the estimated nitrogen leaching, as a mean value for 330 fields, decreased from 53 to 50 kgN ha−1, due to adjustments of the agricultural practices. Monitoring of stream transports showed values of the same magnitude after correction for retention and other sources. In this short time perspective, decreases in transport due to changes in agricultural practices could not be separated from influence of weather conditions. In comparison to results from the Swedish monitoring programme for agriculture, the measured transports were normal for the region, where annual variation in precipitation and runoff is large. Theoretically, nitrogen leaching could be reduced by one third without any major economic constraints for the farmers. In general, the farmers were positive to advice and willing to try new farming techniques even if some measurements were not fully implemented during the investigation period.
A model for decentralised grey wastewater treatment system in Singapore public housing
Authors: Lim J. , Jern Ng Wun , Chew K.L. , Kallianpur V.
Published: May 2018

Global concerns over the sustainable use of natural resources provided the impetus for research into water reclamation from wastewater within the Singapore context. The objective of the research is to study and develop a water infrastructure system as an integral element of architecture and the urbanscape, thereby reducing the need for the large area requirements associated with centralised treatment plants. The decentralised plants were considered so as to break up the large contiguous plot of land otherwise needed, into smaller integrated fragments, which can be incorporated within the housing scheme. This liberated more usable space on the ground plane of the urban housing master plan, enabling water-edge and waterscape relationships within both the private and public domains of varying scale.
Modeling fish community dynamics in the Florida Everglades: role of temperature variation
Authors: Al-Rabai’ah H.A. , Koh H.L. , DeAngelis D. , Lee H.L.
Published: May 2018

Temperature variation is an important factor in Everglade wetlands ecology. A temperature fluctuation from 17°C to 32°C recorded in the Everglades may have significant impact on fish dynamics. The short life cycles of some of Everglade fishes has rendered this temperature variation to have even more impacts on the ecosystem. Fish population dynamic models, which do not explicitly consider seasonal oscillations in temperature, may fail to describe the details of such a population. Hence, a model for fish in freshwater marshes of the Florida Everglades that explicitly incorporates seasonal temperature variations is developed. The model's main objective is to assess the temporal pattern of fish population and densities through time subject to temperature variations. Fish population is divided into 2 functional groups (FGs) consisting of small fishes; each group is subdivided into 5-day age classes during their life cycles. Many governing sub-modules are set directly or indirectly to be temperature dependent. Growth, fecundity, prey availability, consumption rates and mortality are examples. Several mortality sub-modules are introduced in the model, of which starvation mortality is set to be proportional to the ratio of prey needed to prey available at that particular time step. As part of the calibration process, the model is run for 50 years to ensure that fish densities do not go to extinction, while the simulation period is about 8 years.

The model shows that the temperature dependent starvation mortality is an important factor that influences fish population densities. It also shows high fish population densities at some temperature ranges when this consumption need is minimum. Several sensitivity analyses involving variations in temperature terms, food resources and water levels are conducted to ascertain the relative importance of temperature dependence terms.
Biofilm formation in a hot water system
Authors: Bagh L.K. , Albrechtsen H.-J. , Arvin E. , Ovesen K.
Published: May 2018

The biofilm formation rate was measured in situ in a hot water system in an apartment building by specially designed sampling equipment, and the net growth of the suspended bacteria was measured by incubation of water samples with the indigeneous bacteria. The biofilm formation rate reached a higher level in the hot water distribution system (2.1 d−1 to 2.3 d−1) than in the hot water tank (1.4 d−1 to 2.2 d−1) indicating an important area for surface associated growth. The net growth rate of the suspended bacteria measured in hot water from the top, middle and bottom of the hot water tank, in the sludge, or in the water from the distribution system was negligible. This indicated that bacterial growth took place on the inner surfaces in the hot water system and biofilm formation and detachment of bacteria could account for most of the suspended bacteria actually measured in hot water. Therefore, attempts to reduce the number of bacteria in a hot water system have to include the distribution system as well as the hot water tank.
Stochastic modelling of phosphorus transfers from agricultural land to aquatic ecosystems
Authors: Whelan M.J. , Hope E.G. , Fox K.
Published: May 2018

This paper describes a simple model of phosphorus (P) transfer from agricultural land to surface waters which incorporates the effects of spatial variability in catchment properties and uncertainty in model parameter values. TOPMODEL concepts are used to estimate water, solute and sediment fluxes to water bodies. The model predicts the spatial distribution of water table depth and saturation-excess overland flow based on topography. Dissolved P (DP) transfer is assumed to occur vertically in the unsaturated zone and laterally in the saturated zone. Readily soluble P is assumed to decrease exponentially with soil depth. Particulate P (PP) transfers are modelled by estimating overland flow discharge and associated sediment transport capacity. Uncertainty in the distribution of soil surface P concentrations and model parameters controlling the mobility of soil P are incorporated using Monte Carlo simulation. Predicted losses of DP are well correlated with discharge and those of PP are episodic. Highest losses of P tended to be predicted near to the stream where the water table is close to the surface. The combination of a deterministic model core with a stochastic generation of model parameters or state variables provides an attractive way of embracing variability and uncertainty in models of this kind.
Half saturation constants for nitrate and nitrite by in-sewer anoxic transformations of wastewater organic matter
Authors: Abdul-Talib S. , Hvitved-Jacobsen T. , Vollertsen J. , Ujang Z.
Published: May 2018

A significant breakthrough and progress have been made in the study of the kinetics of microbial transformation in sewers under aerobic and under changing aerobic/anaerobic conditions. Fundamental knowledge on anoxic kinetics of wastewater is still lacking, so it is not now possible to apply an integrated approach to municipal wastewater treatment incorporating sewer networks as a bio-chemical reactor. This paper presents the results of studies on determining half saturation constants for nitrate, KNO3, and nitrite, KNO2, in raw wastewater. The average values of KNO3 and KNO2, determined from experiments conducted on 7 different wastewater samples were found to be 0.76 gNO3-N/m3 and 0.33 gNO2-N/m3 respectively.
Denitrifying activity measurements using an anoxic titration (pHstat) bioassay
Authors: Foxon K.M. , Brouckaert C.J. , Rozzi A.
Published: May 2018

An anoxic titrimetric test was investigated for measuring denitrifying activity in an activated sludge system. The method measures the amount of acid that is required to maintain the pH set-point value in a batch denitrification experiment. An iterative algorithm was implemented to extract nitrate uptake rate (NUR) data from titration data, since the accumulation and depletion (stripping) of reaction by-products HCO3- and CO2 affects the direct calculation of denitrifying activity from titration data. This method was performed using an automatic pH-stat acid dosing system, and the data were analysed using the simulation software package, AQUASIM.
Sequencing batch reactor treatment of tannery wastewater for carbon and nitrogen removal
Authors: Murat S. , Atesş Genceli E. , Tasşli R. , Artan N. , Orhon D.
Published: May 2018

The paper evaluates the organic carbon and nitrogen removal performance of the sequencing batch reactor (SBR), technology for tannery wastewater. For this purpose, a pilot-scale SBR was installed on site to treat the plain-settled tannery effluent. The study involved wastewater characterization, start-up and operation of the reactor for carbon and nitrogen removal and model evaluation of system performance. Its removal efficiency was compared with that of the existing continuous-flow activated sludge system providing full treatment to wastewater from the Istanbul Tannery Organized Industrial District.
Willingness to pay for flood and ecological risk reduction in an urban watershed
Authors: Clark D.E. , Novotny V. , Griffin R. , Booth D. , Bartošová A. , Daun M.C. , Hutchinson M.
Published: May 2018

Urban watershed managers frequently must address alternative policy goals; flood control and ecological risk reduction. This study combines hydrologic models of flood control and biotic models of ecologic risk with economic models of willingness-to-pay and psychological models of risk processing and planned behavior to evaluate these two alternative policy objectives. The findings reveal that flood risk exposure, especially for those individuals who would remain outside the 100 year flood plain if the project were enacted, does influence the financial support that local residents would be willing to make to a flood control project. Other important determinants include demographic factors such as income, and attitudinal measures of the respondent. Expanding the scope of the project to include ecological risk reduction does not, however, appear to change the average willingness-to-pay for a project.
Development of a risk-based TMDL assessment approach using the integrated modeling system GIBSI
Authors: Rousseau A.N. , Mailhot A. , Villeneuve J.-P.
Published: May 2018

Using the integrated modeling system GIB SI and a case study, this paper presents the development of a risk-based TMDL assessment approach that links wet (nonpoint/diffuse) and dry weather (point) sources to a probability of exceeding water quality standards (WQS) governing wateruses. The case study focused on determining whether WQS defining recreational uses of water requiring direct and prolonged contact were attainable if the waste water effluent of a small town was treated using aerated lagoons and if the agricultural nonpoint source (NPS) loads were reduced using different fertilization rates. Dry weather sources were assumed to solely contribute to bacteriological impairment of the studied river reach. Meanwhile, both wet and dry weather sources were assumed to contribute to aesthetic impairment. Simulation results showed that treating the waste water effluent while reducing the agricultural NPS loads by 27% allowed on average over a four-year study period for attainment of the bacteriological WQS 100% of the summer time while lowering the probability of exceeding theaesthetic WQS from 0.32 to 0.19 (30 to 18 days). The results of this study showed this risk-based assessment approach was well suited to establish TMDL. These probabilities should be evaluated using long meteorological series.
Different options for metal recovery after sludge decontamination at the Montreal Urban Community wastewater treatment plant
Authors: Meunier N. , Blais J.F. , Lounès M. , Tyagi R.D. , Sasseville J.L.
Published: May 2018

The MUC (Montreal Urban Community) treatment plant produces approximately 270 tons of dry sludge daily (270 tds/day) during the physico-chemical treatment of wastewater. Recently, this treatment plant endowed a system of drying and granulation of sludge for valorization as an agricultural fertilizer having a capacity of 70 tds/day (25% of the daily sludge production). However, the metal content (mainly Cu and Cd) of the sludge surpasses the norms for biosolids valorization. In order to solve this problem, a demonstration project, from the lab scale to the industrial pilot plant, was carried out to test the Metix-AC technology for the removal of metals. A strongly metal-loaded filtrate was generated during the sludge decontamination. Tests concerned the study of the metal recovery by total precipitation and selective precipitation, as well as the use of alternative products for the metal precipitation. Other works consisted to simulate the acid filtrate recirculation from the decontaminated sludge (25% of the total volume) in the untreated sludge (75% of the total volume) intended for the incineration. The total precipitation with hydrated lime appeared effective for the recovery of metals (87% Cd, 96% Cr, 97% Cu, 98% Fe, 71% Ni, 100% Pb, 98% Zn). However, this option entails the production of an important quantity of metallic residue, which should be disposed of expensively as dangerous material. The selective iron precipitation does not appear to be an interesting option because the iron in solution within the leached sludge was principally present in the form of ferrous iron, which cannot be precipitated at pH lower than five. On the other hand, the use of commercial precipitating agents (TMT-15, CP-33Z, CP-NB and CPX) without pH adjustment of filtrate gave good results for the recovery of Cu and, to a lesser degree for the recovery of Pb. However, the efficiency for the other metals' (Cd, Cr, Fe, Ni and Zn) recovery was weaker (< 25%). Finally, the acid filtrate recirculation containing solubilised metals in untreated sludge destined for incineration appears to be the most interesting option. Metals in solution in the acid filtrate, precipitate or adsorb effectively (97% Cd, 97% Cr, 99% Cu, 82% Ni, 100% Pb and 87% Zn) on the solids of the untreated sludge. Moreover, TCLP tests were done on ashes produced during the incineration of sludge mixed with the acid filtrate produced during sludge decontamination. These tests showed that there were no significant differences, as regards the extractability of metals, between such ashes and those produced during the untreated sludge incineration without addition of filtrate. Therefore, it was predictable that this method can respect the current environmental standards required by the different governmental authorities.
A new model for anaerobic processes of up-flow anaerobic sludge blanket reactors based on cellular automata
Authors: Skiadas I.V. , Ahring B.K.
Published: May 2018

The advantageous performance of the UASB reactors is due to the immobilisation of the active biomass, since bacteria coagulate forming aggregates usually called granules. Changes in organic loading rate, hydraulic loading rate or influent substrate composition usually result in changes in granule characteristics and lead to different reactor behaviour. A dynamic mathematical model has been developed for the anaerobic digestion of a glucose based synthetic wastewater in UASB reactors. Cellular automata (CA) theory has been applied to simulate the granule development process. The model takes into consideration that granule diameter and granule microbial composition are functions of the reactor operational parameters and is capable of predicting the UASB performance and the layer structure of the granules.
Hydrolysis kinetics of dissolved polymer substrates
Authors: Sanders W.T.M. , Zeeman G. , Lettinga G.
Published: May 2018

In this paper, the relation between the hydrolysis rate of dissolved polymer substrates and sludge concentration was investigated in two ways, viz. by laboratory experiments and by computer simulations. In the simulations, the hydrolysis of dissolved polymer components was regarded as a general depolymerisation process in which the bonds of the parent molecule break randomly until only monomer and dimer components remain. The results illustrate that for the hydrolysis of dissolved polymer substrates the enzyme activity is the rate-limiting factor. Moreover, a general depolymerisation process can describe the enzymatic hydrolysis of these components.
Improved alkaline stabilization of municipal wastewater sludge
Authors: Mendez J.M. , Jiménez B.E. , Barrios J.A.
Published: May 2018

In Mexico, physicochemical sludge contains high levels of pathogens; and alkaline stabilization is an alternative for their control. However, the odours caused mainly by ammonia generation represent a disadvantage. On the other hand, the ammonia is known as an effective disinfectant. The aim of this study was to evaluate the disinfectant properties of ammonia in sludge, and use it in a closed alkaline stabilization system, which, not only copes with odours but also increases the efficiency of the process. Raw sludge from a municipal wastewater treatment plant using a physicochemical process was used. Ammonia was applied in doses from 10 to 50% w/w; also, doses from 5 to 40% of CaO were applied in open and closed systems and raw and treated sludge quality was evaluated. Results showed that ammonia removed 6 and 5 logs of faecal coliforms and Salmonella spp., respectively and up to 94% of viable helminth ova. The closed system was more efficient than the open system when applying doses from 5 to 20% of CaO. Finally, the results indicate that the ammonia represents an alternative to disinfecting wastewater sludge and it can be used to enhance alkaline stabilization processes.
Effect of the employment of biosolids as recovery agent for degraded areas
Authors: Andreoli C.V. , de Castro L.A.R. , Picinatto A.G. , Pegorini E.S.
Published: May 2018

The solid residue generated from the sewage treatment receives the denomination of sewage sludge, being also called biosolid. The present work compared the effect of 3 levels of fertilization (sewer sludge, mineral fertilization and proof) in the recovery of areas with 2 levels of soil degradation simulation (removal of 15 cm and 30 cm of soil), plus a proof. In the parcels destined for the biosolid, 40 dry t./ha of aerobic limy stabilized 30% had been used. The content of Ca+Mg, K, V% and CTC in the parcels that received biosolids had its value increased by 11.7%, 28.0%, 8.3% and 6.0% respectively, when compared with the values of the proof at the end of the maize culture. The contents of phosphorus were statistically higher for the Tukey test at 5% of probability in the treatment with biosolid, verifying also the trend of accumulation of phosphorus in the parcels, with the simulated level of degradation of 30 cm. There was a significant increase in carbon content due to the application of biosolids. The production of dry substance was still evaluated, where the biggest productions had been statistically verified in the treatments, being slightly influenced by the different levels of soil degradation, evidencing the great capacity of silt as recovery agent.
Pilot-plant study on anaerobic treatment of a lipid- and protein-rich food industrial wastewater by a thermophilic multi-staged UASB reactor
Authors: Tagawa T. , Takahashi H. , Sekiguchi Y. , Ohashi A. , Harada H.
Published: May 2018

An on-site pilot-scale experiment was conducted to investigate the performance of a multi-staged UASB (MS-UASB) reactor by feeding with a food processing wastewater containing high strength of lipid and protein. The reactor was operated at a thermophilic condition (55°C) for a period of 600 days. The reactor finally achieved 50 kgCOD·m−3ád−1 with a soluble COD removal of 90% (based on the influent total COD versus the effluent filtered COD), while the overall COD removal (based on the effluent COD-total) was considerably unsatisfactory at around only 60–70%. The presence of high strength of lipid and protein along with high concentration of Mg and Ca ions in the raw wastewater caused a severe scum and/or insolubilized substance formation within the UASB sludge bed, resulting in hindering the contact efficiency between substrate and sludge. The replacement of active microbial granules in the sludge bed with the insolubilized protein and lipid brought about deterioration of sludge methanogenic activity.
Reuse of sewage sludge as raw material of Portland cement in Japan
Authors: Taruya T. , Okuno N. , Kanaya K.
Published: May 2018

A potential alternative of sewage sludge reuse is the substitute of raw material for Portland cement. This paper overviews Japanese implementation of this and discusses the best selection of pretreatment for this purpose. The pretreatment includes dewatering, incineration, and lime treatment.
Removal of helminth eggs and fecal coliforms by anaerobic thermophilic sludge digestion
Authors: Cabirol N. , Rojas Oropeza M. , Noyola A.
Published: May 2018

Anaerobic digestion of two types of waste sludge was applied in order to assess the suitability of thermophilic conditions for the stabilization of organic matter and removal of fecal coliforms and helminth eggs. Feeding sludge was taken from an activated sludge municipal facility (BS) and from an enhanced primary treatment municipal plant (EPT). As an accompanying experiment, mesophilic digesters were also operated. The four digesters (M1, M2, T1, T2) had a 5 litre volume and an egg shape. A highly stabilized material was obtained at both temperatures with BS type of sludge, taking the reduction of volatile fraction of suspended solids (%RVSS) as indicator (84% for M1 and 74% for T1). In general, EPT sludge was a more difficult substrate, if compared with BS sludge; thermophilic condition was better adapted than mesophilic for this kind of sludge. Satisfactory reductions on counts of fecal coliforms and helminth eggs were achieved under thermophilic digestion for both types of feeding sludge. T1 digester, fed with biological sludge, removed fecal coliforms below 1000 MPN/gTS and helminth eggs down to 0.28 HELarval/gTS, at an HRT of 20 days. As a general conclusion, anaerobic thermophilic digestion may be an appropriate option for sludge stabilization, in order to meet EPA Class A biosolids final disposal regulations. However, further research is needed in order to consistently remove helminth eggs and fecal coliforms from waste sludge at shorter hydraulic retention times.
Using a UASB reactor for thickening and digestion of discharged sludge from submerged aerated biofilters
Authors: Franci Gonçalves R. , Veronez F.A. , Kissling C.M.S. , Cassini S.T.A.
Published: May 2018

Results from one year of experimental monitoring the wastewater treatment plant of UFES (Federal University of Espírito Santo) treating a residential urban area of city of Vitoria ES, Brazil, have shown a good performance by a UASB reactor as a part of domestic sewage treatment and also performing aerobic sludge thickening and digestion. The total solids concentration around 6% was obtained in main sludge blanket at bottom of reactor despite a high daily aerobic sludge load discharged from four aerobic submerged biofilters containing 0.4% TS and 80% of VS/TS. Similar values were found in another experimental period when the reactor was fed only with raw domestic sewage. The average removal efficiency of organic matter and suspended solids observed for domestic sewage treatment are around 63% of SS and 64% COD. These results were obtained in the UASB reactor working with or without aerobic sludge recycling, with constant or variable load and hydraulic detention time (HDT) less than 6 hours. A proposed mass balance allows a theoretical assessment of aerobic sludge digestion and accumulation into UASB reactor.
Controlling calcium precipitation in an integrated anaerobic–aerobic treatment system of a “zero-discharge” paper mill
Authors: van Lier J.B. , Boncz M.A.
Published: May 2018

The pulp and paper industry uses significant amounts of water and energy for the paper production process. Closing the water cycles in this industry, therefore, promises large benefits for the environment and has the potential of huge cost savings for the industry. Closing the water cycle on the other hand also introduces problems with process water quality, quality of the end-product and scaling, owing to increased water contamination. An inline treatment system is discussed in which anaerobic-aerobic bio-reactors perform a central role for removing both organic and inorganic pollutants from the process water cycle. In the proposed set-up, the organic compounds are converted to methane gas and reused for energy supply, while sulphur compounds are stripped from the process cycle and calcium carbonate is removed by precipitation. Improved control of the treatment system will direct the inorganic precipitates to a location where it does not adversely affect paper production and process water treatment. A simulation program for triggering and controlling CaCO3 precipitation was developed that takes both biological conversions and all relevant chemical equilibria in the system into account. Simulation results are in good agreement with data gathered in a full-scale “zero-emission” paper plant and indicate that control of CaCO3 precipitation can be improved, e.g. in the aerobic post-treatment. Alternatively, a separate precipitation unit could be considered.
Sludge bed development in denitrifying reactors using different inocula-performance and microbiological aspects
Authors: Etchebehere C. , Errazquin M.I. , Cabezas A. , Pianzzola M.J. , Mallo M. , Lombardi P. , Ottonello G. , Borzacconi L. , Muxí L.
Published: May 2018

Aerobic and methanogenic consortia were evaluated as inocula for laboratory scale denitrifying reactors, fed with a synthetic wastewater with acetate as the main electron donor. The denitrifying microflora of inocula and reactors was evaluated by specific denitrifying activity, enumeration and isolation of denitrifiers, which were screened by amplified ribosomal DNA restriction analysis. Reactor performance was monitored by COD and nitrate removal efficiencies and granule size. The aerobic sludge failed to form granules, probably due to the development of a filamentous, nitrate-reducing organism which was characterised by 16SrDNA sequencing as Bacillus cereus. The methanogenic sludge showed denitrifying activity and adapted very rapidly to denitrifying conditions in the two reactors seeded with granules of different sizes. Denitrifiers grew around the granules, increasing the specific denitrifying activity of the sludge over 10-fold. Exopolymer-forming organisms, belonging to the same species, were isolated from both reactors. Granule size increased during operation, but flotation of the aggregates, related to gas retention was observed.
Human impacts on hydrology in the Pantanal wetland of South America
Authors: Hamilton S.K.
Published: May 2018

Inundation patterns in the Pantanal remain in a relatively natural state, yet a number of significant human influences have occurred in the past, and there is potential for more severe human impacts as development of the region continues in the future. The objectives of this paper are 1) to briefly review the linkages between hydrology and ecological structure and function in the Pantanal; 2) to review some documented cases of historical influences of human activities on hydrology in the region; and 3) to consider potential future impacts, particularly in regard to the recently proposed navigation project known as the Paraguay-Paraná Waterway (or Hidrovía).
Institutionalising cost sharing for catchment management: lessons from land and water management planning in Australia
Authors: Marshall G.R.
Published: May 2018

A recurring theme in recent Australian reports on integrated catchment management (ICM) has been the need to institutionalise more formally the cost-sharing commitments made within this domain. This represents a significant departure from earlier visions of ICM as essentially promoting voluntary uptake of resource-conservation measures. Two important questions raised by this nascent policy shift are addressed in this paper. Firstly, how might cost-sharing arrangements be given greater formality without undermining the efforts of ICM to increase the preparedness of civil stakeholders to voluntarily, or informally, accept responsibility for sharing costs? Secondly, how is it possible to formalise cost-sharing arrangements so that the transaction costs of enforcing compliance with them remain affordable? Answers to these questions are explored through a case study of the Land and Water Management Planning Program now being successfully implemented in the irrigation districts of the central-Murray region of southern inland New South Wales (NSW) surrounding Deniliquin. The sophisticated system of institutional arrangements introduced in the program to facilitate monitoring, enforcement and adaptive management of cost-sharing commitments is discussed, and insights into how informally motivated cooperation can enhance the affordability and political feasibility of formal arrangements are presented.
Achieving river integrity through natural resource management and integrated catchment management legislative frameworks
Authors: Maher M. , Nevill J. , Nichols P.
Published: May 2018

This paper reports on a project which further refines a model legislative framework first identified in a Land and Water Australia project in 1999. This framework is benchmarked against legislative excerpts from within Australian jurisdictions, as well as the major policy initiatives of the Council of Australian Governments (COAG) water reform agenda, the Commonwealth's National Action Plan on Salinity and Water Quality, and others. The model framework has been heavily influenced by current thinking on ecological systems, good governance, and organisational management. Another important product of the report is a statement of model statutory objectives and principles, suitable for use in water resource legislation.
Representative freshwater reserves: better late than never
Authors: Nevill J. , Phillips N.
Published: May 2018

Representative reserves (protected areas) are an accepted component of terrestrial and marine biodiversity conservation programs. Additionally, representative reserves have important values in protecting ecosystems of special importance, and in providing ecologically based benchmarks useful in assessing the sustainability of management programs. However, in spite of international and national commitments, Australian State governments have been slow to establish systems of representative reserves in freshwater environments.

A central recommendation involves the establishment of agreed national methods for the classification of freshwater ecosystems into (“representative”) categories which can be incorporated into a comprehensive national inventory. A second key recommendation involves the development of a national approach to identifying gaps in the existing reserve system relating specifically to freshwater ecosystems.
Environmental water in a regulated river system: the Murrumbidgee River planning approach to the determination of environmental needs
Authors: Shields J. , Good R.
Published: May 2018

The major platform of the Council of Australian Governments (COAG) water reform program is the equitable and sustainable sharing of surface and groundwater resources between the environment and consumptive water users. In the regulated section of the Murrumbidgee River below Burrinjuck Dam, approximately 2,800 GL of the available surface water (4,300 GL) is diverted or extracted for irrigation uses in the Murrumbidgee Irrigation Area and Districts, and in the Coleambally Irrigation Area.

Environmental flow rules have been developed for the Murrumbidgee which provide for an allocation of water to the environment but on the basis of no more than a 10% impact on farm-gate income of irrigation farmers. This provision limits the volume of water that can be used for environmental purposes, so the most effective use must be made of it.

To identify and quantify the benefits to the environment of this limited additional volume of water and to determine the most effective use of the water, an ldquo;environmental spreadsheet matrix” has been developed. This paper outlines the development and use of the matrix in the planned implementation of flow regimes appropriate to the protection and enhancement of riparian and aquatic ecosystems and ecological processes.
Waste management systems of dairy cattle farms in Japan
Authors: Shima E. , Svoboda I.F. , Tsutsumi S. , Ohkubo H.
Published: May 2018

Recently, the size of livestock farms in Japan has been expanding and the pollution from farm wastes has become a serious problem in rural areas. Therefore it is necessary to design treatment strategies and improve the recycling of livestock manure for sustainability of agriculture in Japan. The dairy cattle waste management systems were studied at dairy farms in Aomori prefecture and in Hokkaido, Japan. The four farms, typical for the respective regions in Japan, were investigated on the basis of the land and livestock size, housing, overall farm and waste management, type of machinery and a farm labour force. A statistical comparison was made for housing, milking and waste handling systems of dairy farms. One of the waste handling strategies was aerobic slurry treatment and land irrigation of the treated liquid fraction. Such methods began to solve some of waste management problems created since 1967 in grassland farming areas of Hokkaido. The irrigation system supplies water fertiliser and organic material to land as well as shortening the spreading times. It recycles livestock resources, increases the soil fertility and rationalises the farm management.
Application of membrane-coupled anaerobic volatile fatty acids fermentor for dissolved organics recovery from coagulated raw sludge
Authors: Kim J.-O. , Somiya I. , Shin E.-B. , Bae W. , Kim S.-K. , Kim R.-H.
Published: May 2018

To investigate the treatment performance of membrane-coupled anaerobic volatile fatty acids fermentor system, the effects of operational parameters for volatile fatty acids production were evaluated through experiments and a mathematical model. The volatile fatty acids recovery ratio was largely affected by the change of hydraulic retention time, reaching its maximum value at 12 hrs. Over the range of hydraulic retention time 8 to 96 hrs, the volatile fatty acids recovery ratio decreased with the increase of hydraulic retention time above 12 hrs, while the ratio of mineralization and gasification increased. Hydraulic retention time and membrane filtration ratio should be maintained less than 1 day and above 0.9, respectively, to attain over 40% of organic materials recovery ratio at 10 days of solids retention time. When the hydrolysis rate constant was 0.01 hr−1, the organic loading rate should be maintained at above 1.0 (kgC/m3/day) to attain over 45% of volatile fatty acids recovery ratio. Based on experimental and simulated results, membrane-coupled anaerobic volatile fatty acids fermentor system was thought to be effective for dissolved organics recovery from coagulated sewage sludge.
Use of recycling through medium size granular filters to treat small food processing industry effluents
Authors: Ménoret C. , Boutin C. , Liénard A. , Brissaud F.
Published: May 2018

Currently there are no suitable wastewater treatment systems for effluents from small food processing industries (dairy, cheese, wine production). Such raw sewages are characterized by high organic matter concentrations (about 10 g COD L−1) and relatively low daily volumes (about 2 m3). An adaptation of attached-growth cultures on fine media processes, known to be easy and inexpensive to use, could fit both the technical and economical context of those industries. Coarser filter particle size distributions than those normally used allow a better aeration and reduce clogging risk. The transit time of the effluent through the porous filter materials is shortened and requires recycling to increase the contact time between the biomass and the substrate. A pilot plant was built to compare the efficiency of two kinds of filter materials, gravel (2-5 mm) and pozzolana (3-7 mm). Two measurement campaigns were undertaken on a full-scale unit dealing with cheese dairy effluents. Both pilot-scale and full-scale plants show high COD removal rates (>95%). Pilot-scale experiments show that accumulation of organic matter leads to the clogging of the recycling filter. To prevent early clogging, a better definition of feeding cycles is needed.
Who eats what? Classifying microbial populations based on diurnal profiles of rRNA levels
Authors: Frigon D. , Arnaiz E. , Oertherf D.B. , Raskin L.
Published: May 2018

Identifying the relationships between various bacterial populations and the substrates they consume is central to the understanding of population dynamics and to the development of process control in activated sludge. However, linking a heterotrophic population to its activity in situ is difficult because ribosomal RNA (rRNA) techniques, while allowing the rapid identification of populations, provide little information about their heterotrophic activity. Activated sludge models describe biodegradation kinetics by classifying substrates into two types: readily and slowly degradable substrates. Assuming that bacterial populations specialize in degrading one type of substrate, their growth rate should be affected differently if the COD loading rate varies diurnally as for a municipal activated sludge system. Modeling results suggested that the growth rates of populations consuming readily degradable substrates vary according to variations in COD loading rate. On the other hand, the growth rates of populations consuming slowly degradable substrates do not change despite the variation in COD loading rate. Since the cellular rRNA level is positively correlated with the growth rate, we hypothesized that the rRNA levels of some populations in municipal activated sludge should increase throughout the day, while they should stay constant for other populations. This hypothesis was verified by monitoring the rRNA level of Acinetobacter (a model population consuming readily degradable substrates) and Gordonia (a model population consuming slowly degradable substrates) in the mixed liquor of a full-scale municipal activated sludge reactor for three weeks.
Evaluating the role of microbial stress response mechanisms in causing biological treatment system upset
Authors: Love N.G. , Bott C.B.
Published: May 2018

It is known that microbial stress mechanisms play a significant role in short-term microbial adaptation to environmental perturbations, and activation of these mechanisms enhance a cell's chance for surviving the perturbation with minimal damage. Although the target of these mechanisms is protective at the cellular level, the effect may be disruptive at the macroscopic level in engineered bioreactor systems. In this paper, it is proposed that these mechanisms are activated in response to wastewater influent perturbations and may be a significant cause of activated sludge treatment process upset. Selected microbial stress responses are reviewed and hypotheses indicating their potential role in treatment process upset are proposed. A research approach that was previously used to identify the mechanistic cause of deflocculation during perturbation by electrophilic chemicals is summarized, and a protocol for future experiments geared toward establishing source-cause-effect relationships for a range of wastewater upset conditions is put forth. Identifying source-cause-effect relationships will provide a basis for development of new monitoring technologies and operational strategies for systems under the influence of influent chemical perturbations.
Bacteriophage-host interaction in the enhanced biological phosphate removing activated sludge system
Authors: Khan M.A. , Satoh H. , Mino T. , Katayama H. , Kurisu F. , Matsuo T.
Published: May 2018

Bacteriophages were isolated from a laboratory scale enhanced biological phosphate removing (EBPR) activated sludge process, and their host range was examined. Bacterial isolates to host the bacteriophages were isolated from the EBPR activated sludge process. Bacteriophages were eluted from the EBPR activated sludge, enriched by incubation with the bacterial isolates, and then tested for plaque formation on each of the bacterial isolates. Out of 12 bacterial isolates isolated, 4 supported plaque formation. Four bacteriophages were obtained from the plaques. The host range test was conducted with the combination of the bacteriophage isolates and the bacterial isolates. Three of the bacteriophages were found to form plaques on more than one host, and one of them formed plaques on both Gram +ve and Gram −ve bacterial isolates. Two of the four bacteriophages failed to form plaques on their original bacterial host, indicating the existence of mutation on either both or one of the host and the bacteriophage. This study strongly suggests that bacteriophages are an active part of the activated sludge microbial ecosystem, having very complex interaction with their host bacteria.
Microthrix parvicella, a specialized lipid consumer in anaerobic–aerobic activated sludge plants
Authors: Nielsen P.H. , Roslev P. , Dueholm T.E. , Nielsen J.L.
Published: May 2018

The in situ physiology of the filamentous bacterium Microthrix parvicella was investigated in anaerobic-aerobic dynamic phases in activated sludge with focus on the uptake of long chain fatty acids (LCFA) and growth. When 14C-labeled oleic acid was added to activated sludge with an excessive growth of M. parvicella, only little 14C-CO2 was produced under anaerobic conditions while a lot was produced under aerobic conditions. Microautoradiographic studies revealed that M. parvicella took up oleic acid under both anaerobic and aerobic conditions, while only a few floc formers were able to take it up under anaerobic conditions. Extraction and separation of the radioactive biomass into different lipid fractions showed that the oleic acid was stored mainly as neutral lipids under anaerobic conditions, whereas conversion to membrane phospholipids occurred almost exclusively under aerobic conditions, indicating growth. The surface properties of M. parvicella and other bacteria were characterized by hydrophobic fluorescent microspheres, which showed that M. parvicella was relatively hydrophobic. Furthermore, a surface-associated extracellular lipase activity was observed, indicating the ability of M. parvicella to degrade lipids near the filament surface. The results support the hypothesis that uptake and storage of LCFA as lipids under anaerobic conditions provide an effective competition strategy against bacteria that can only take up LCFA under aerobic conditions. Thus, M. parvicella seems to be a specialized lipid consumer with a physiological potential analogous to PAOs and GAOs being able to take up LCFA (but not short chain fatty acids or glucose) under anaerobic conditions and subsequently use the storage material for growth when nitrate or oxygen are available as electron acceptors.
Analysis of microbial community that performs enhanced biological phosphorus removal in activated sludge fed with acetate
Authors: Onuki M. , Satoh H. , Mino T.
Published: May 2018

Enhanced biological phosphorus removal (EBPR) activated sludge was operated in a laboratory-scale sequencing batch reactor (SBR) fed with acetate as the sole carbon source. The microbial community of the sludge was analyzed using the polymerase chain reaction (PCR) – denaturing gradient gel electrophoresis (DGGE) method for about 2 months of start-up period. As a result, the number of major bands decreased during the enrichment, indicating that the microbial community structure was getting simpler. Since the phosphate removal activity was maintained at a high level, the bacteria which still remained at the end can be considered as the important bacteria playing key roles in the present EBPR sludge, maybe polyphosphate accumulating organisms (PAOs). The dominant band in the last sample on the DGGE gel was excised and the DNA recovered from it was sequenced. The sequence was closely related to one of the putative PAOs group which Crocetti et al. (2000) and Hesselmann et al. (1999) have proposed. This PAOs group is closely related to the Rhodocyclus group (b-Proteobacteria). The fluorescence in situ hybridization (FISH) method with the probe specific for this PAOs group and the DAPI staining at a phosphate-probing concentration indirectly showed that these Rhodocyclus related bacteria really accumulated polyphosphate.