bluuebunny/crossref_metadata_2025 huggingface dataset:
Does batch operation enhance oxidation in subsurface constructed wetlands?
Authors: Stein O.R. , Hook P.B. , Biederman J.A. , Allen W.C. , Borden D.J.
Published: May 2018

Two side-by-side experimental sub-surface flow systems allowed direct comparison of wetland performance under batch and continuous-flow operation. One system consisted of microcosm “columns” operated in 20-day batch mode while the second consisted of continuous-flow “cells” operated at a five-day residence time. Both systems treated identical synthetic domestic wastewater for two years and then treated identical synthetic mine-impacted water for one year. Each system had replicates planted with Typha latifolia, Scirpus acutus and unplanted controls. Temperature was cycled annually between 4 to 24°C. Results indicated that plant species, season, and mode of operation interacted strongly in controlling dynamics of COD, nitrogen species, phosphate, sulfate, and redox potentials. In batch-loaded columns, between-species differences in oxidation and COD removal were large in winter, during plant dormancy, but absent in summer; COD removal, sulfate concentration, and redox potentials were closely correlated, suggesting that variation in root-zone oxygenation due to seasonal plant growth patterns and temperature-dependent plant and microbial respiration may explain observed differences. In the continuous-flow cells, species and seasonal differences were minimal or non-existent, indicating that under continuous-flow operation plants either did not influence root zone oxidation or that this influence had no effect on wetland performance for COD and nutrient removal or sulfate reduction.
Influence of operational conditions on biofilm specific activity of an anaerobic fluidized bed reactor
Authors: García-Morales J.L. , Romero L.I. , Sales D.
Published: May 2018

A key parameter in water and wastewater treatment technology is the biomass activity in terms of substrate removal ability. The effects of organic load rate and percentage of bed expansion on biofilm specific methanogenic activity were determined in an anaerobic fluidized bed reactor treating wine-distillery wastes in the thermophilic range (55°C). The proposed activity tests are highly reproducible: an experiment with three identical tests has shown that the standard deviation with respect to the mean values is less than 3%. Specific tests are applied to measure the maximum methanogenic activities of the biomass carrier in lab-scale anaerobic biofilm reactors. These tests have been successfully applied for monitoring the support colonization process and the evolution of biofilm activity in reactors, anaerobic filter and fluidized bed, with different operating conditions. The results show a dependence between the percentage of bed expansion and the specific activity of methanogenic microbiote on biofilm. There is a relationship between the percentage of bed expansion, the shear stress on the biofilm and the hydrodynamic conditions in the system. Initial biofilm detachment can be compensated with the increase of biomass and of its activity due to the reduction of the substrate diffusional limitations to the microorganism growth inside the support pores.
Using constructed wetlands to treat subsurface drainage from intensively grazed dairy pastures in New Zealand
Authors: Tanner C.C. , Long Nguyen M. , Sukias J.P.S.
Published: May 2018

Performance data, during the start-up period, are presented for constructed wetlands treating subsurface drainage from dairy pastures in Waikato (rain-fed) and Northland (irrigated), North Island, New Zealand. The wetlands comprised an estimated 1 and 2% of the drained catchment areas, respectively. Nitrate concentrations were high in the drainage inflows at both sites (medians 10 g m-3 at Waikato and 6.5 g m-3 at Northland), but organic N was also an important form of N at Waikato (37% of TN). Comparison of wetland inflow and outflow nutrient concentrations showed overall nutrient reductions during passage through the wetlands for NO3-N (34 and 94% for medians, respectively), TN (56 and 33%, respectively), and DRP (80%, Northland only). Median NH4-N (both sites) and DRP (Waikato) concentrations showed apparent increases between the wetland inlets and outlets. However, a mass balance calculated for the 3 month preliminary monitoring periods showed substantial mass removal of DRP (80%) and all measured forms of N (NO3-N 78%, NH4-N 41%, Org-N 99.8% and TN 96%) in the Waikato wetland. Monitoring of these systems needs to be continued through a range of seasons and years to fully assess their long-term performance.
The effect of wastewater discharge on biomass production and nutrient content of Cyperus papyrus and Miscanthidium violaceum in the Nakivubo wetland, Kampala, Uganda
Authors: Kansiime F. , Nalubega M. , van Bruggen J.J.A. , Denny P.
Published: May 2018

The nutrient content of representative plant parts and biomass production in the Nakivubo wetland, correlation of these with the wastewater flow patterns and determination of nutrient uptake, storage and biomass production of Cyperus papyrus (papyrus) and Miscanthidium violaceum was studied. On average papyrus vegetation under the influence of wastewater had higher nutrient content in the above ground biomass (1.6% N and 0.23% P on dry weight basis) than those not affected (0.98% N and 0.18% P). The biomass varied between 3,529-5,844 g/m2 and 883-1,156 g/m2 in the two respective sites. The juvenile plants of papyrus and Miscanthidium had higher concentrations of P and N in their organs compared to the mature ones. Considering the nutrients stored by the dominant vegetation and the current flow patterns of wastewater in the Nakivubo wetland, harvesting of the above ground biomass once a year, would remove 7.7% of the N input and 15.8% of the P input of the annual total load entering the wetland. However, if the wetland is bio-manipulated and the wastewater flow distributed over the whole wetland, up to 70% nitrogen and 76% phosphorus would be removed by harvesting above ground papyrus biomass.
Balancing priorities: the role of industry in water resource management
Authors: Giuliano L. J.
Published: May 2018

Together, the 40,000 men and women around the world who make up ITT Industries and our many colleagues in the water and wastewater treatment industries are working with those of you in the public, not-for-profit, academic and community sectors to confront the many water-related issues we face on a global basis. Should we call this situation a crisis? As discussed in the various sessions of this Symposium, in many ways we are facing a crisis in the water world. But of course, we are also seeing many positive developments in the field, and this provides hope for the future.
Influence of multiple substrates on anaerobic protein degradation in a packed-bed bioreactor
Authors: Tommaso G. , Ribeiro R. , Varesche M.B.A. , Zaiat M. , Foresti E.
Published: May 2018

Data on the influence of substrate composition on the anaerobic degradation of bovine serum albumin (BSA) in a bench-scale packed-bed reactor are presented and discussed from the standpoint of substrate consumption kinetics. The experiments were carried out in a horizontal-flow anaerobic immobilized biomass (HAIB) reactor fed with BSA based substrates. BSA was the sole carbon source in the first one, while the others were composed of BSA, carbohydrates and lipids. In all the experiments, the HAIB reactor was operated at the hydraulic detention time of 4 hours. The reactor's performance was evaluated based on physicochemical and chromatographic analyses and also on microscopy techniques. A kinetic model of irreversible first-order series-parallel reactions with two intermediate products was proposed, allowing evaluation of the microbial consortiumÕs affinity with the substrates and the metabolic compounds formed. As the first-order kinetic model adhered quite well to the experimental data, the initial protein degradation rates (k) were estimated. The presence of carbohydrates and lipids led the initial protein degradation rate to be reduced. However, the system fed with protein and carbohydrates showed higher process stability.
Accumulation of long chain fatty acids onto anaerobic sludge under steady state and shock loading conditions: effect on acetogenic and methanogenic activity
Authors: Pereira M.A. , Cavaleiro A.J. , Mota M. , Alves M.M.
Published: May 2018

Accumulation of substrate onto the biomass was quantified under steady-state and shock conditions in a fixed bed reactor fed with an oleic acid-based synthetic effluent. The accumulation of substrate onto the sludge was more dependent on oleic acid concentration than on oleic acid loading rate and decreased the acetogenic, acetoclastic and hydrogenophilic activity. However, even when the methanogenic activity measurements indicate a severe inhibition, the anaerobic sludge was able to methanise efficiently the accumulated substrate that was mainly adsorbed LCFA. Methanogenic activity measurements for a sludge loaded with 2,861 mg COD/gVSS as LCFA, revealed that only hydrogenophilic activity was detetcted, whereas the methanogenic activities with acetate, propionate and butyrate as substrates were null. However the methanogenic activity of the same sludge after allowing the depletion of the adsorbed LCFA were significantly enhanced in the presence of all substrates, except in propionate. A discussion about the relative importance of metabolic inhibition and transport limitations for the anaerobic degradation of LCFA is launched.
Stakeholder involvement in water management: necessity or luxury?
Authors: Morrison K.
Published: May 2018

Stakeholder involvement in water management is widely recognized as an important component of the design and implementation of sustainable water management initiatives. Despite this, there remains a deep-rooted resistance to the widespread implementation of programs to prioritize such involvement (as witnessed by, for example, the low priority given to the public involvement element of the European Union Water Framework Directive). This paper addresses the issue of stakeholder involvement by first confronting the fact that it is not a water issue, per se. Such diverse fields as economics, agriculture, public health, pollution prevention, business and education have also identified stakeholder involvement as a difficult but necessary component of successful action in their fields. For the water sector, the issue of stakeholder involvement as either a necessity for sustainable water management, or a luxury to be used to complement traditional approaches, is discussed.
Water, food and environment: conflict or dialogue?
Authors: Rijsberman F. , Mohammed A.
Published: May 2018

Increased water conflicts are the result of the rapidly increasing relative water scarcity in many basins to which water institutions have not yet successfully adapted. The Dialogue on Water, Food and Environment is a program of activities that employs processes at international, national, basin and local scales to help build bridges between agriculture and the environment.
Robust regulation of anaerobic digestion processes
Authors: Mailleret L. , Bernard O. , Steyer J.P.
Published: May 2018

This paper deals with the problem of controlling anaerobic digestion processes. A two-step (i.e. acidogenesis-methanization) mass balance model is considered for a 1 m3 fixed bed digester treating industrial wine distillery wastewater. The control law aims at regulating the organic pollution level while avoiding washout of biomass. To this end, a simple output feedback controller is considered which regulates a variable strongly related to the Chemical Oxygen Demand (COD). Numerical simulations assuming noisy measurements first illustrate the robustness of this control procedure. Then, the regulating procedure is implemented on the considered anaerobic digestion process in order to validate and demonstrate its efficiency in real life experiments.
Bicarbonate dosing: a tool to performance recovery of a thermophilic methanol-fed UASB reactor
Authors: Paulo P.L. , van Lier J.B. , Lettinga G.
Published: May 2018

The thermophilic-anaerobic treatment of methanol-containing wastewater in an upflow anaerobic sludge blanket (UASB) reactor, was found to be quite sensitive to pH shocks, both acid and alkaline. The results of the recovery experiments of sludge exposed to an alkaline shock, indicated that the addition or deprivation of sodium bicarbonate (NaHCO3) in the medium, plays an important role in the competition of methanogens and (homo)acetogens for methanol. In addition, caution has to be taken when using NaHCO3 for buffering methanol-containing wastewaters, since its introduction in the system will favour (homo)acetogenesis when proper conditions are not established. Based on these results, a recovery strategy for methanogenesis was proposed where bicarbonate is supplied stepwise, and the reactor is operated in a batch mode. This strategy was found to be appropriate, i.e. the results revealed that the recovery of methanogenesis on methanol from a reactor upset or complete failure caused by pH shock is possible, even in systems where (homo)acetogens are outcompeting methanogens. The time and the number of feedings required will depend on the degree of deterioration of the sludge.
Factors affecting constancy of acetate concentration and correct determination of methanogenic activity in pH-stat experiments
Authors: Mösche M. , Meyer U.
Published: May 2018

The determination of methanogenic activity with a pH-stat titration bioassay is evaluated utilising a mathematical model of this system. For given kinetic parameters and experimental conditions the model calculates the development of titrant flow and acetate concentration during experiments. Simulations of experiments under various conditions are compared. They show that the original method inherently causes a strong drift of acetate concentration during the experiments and a misestimation of methanogenic activity. As a solution to these disadvantages the addition of sodium hydroxide to the titrant and a careful control of pH during flushing the reactor with gas prior to the experiment are recommended. In this way a better constancy of acetate concentration and a more accurate determination of methanogenic activity should be achievable. The accuracy of this method is limited by the stability of pH-electrode calibration parameters.
Workshop 2 (synthesis): water pollution abatement within the industrial sector
Authors: Matsui S. , Oatridge J. , Blomqvist A.
Published: May 2018

This workshop aimed at demonstrating and discussing how effective abatement of water pollution can be achieved through introducing cleaner technologies, recycling and reuse of water, and implementing new public policy measures.
Towards poverty alleviation: the water sector perspectives
Authors: Ahmad Q.K.
Published: May 2018

Water and poverty interface in many different ways. Sustainable management (i.e. development, allocation and utilization) of water resources is therefore a process-element of sustainable human development. This paper looks into water-poverty interfaces as well as into approaches to, and tools of, managing water in such a manner that water sector activities can contribute to alleviation of poverty. It gives a southern perspective and includes a case study of the evolving water management regime in Bangladesh.
Alleviating water scarcity in Northern China: balancing options and policies among Chinese decision-makers
Authors: Lasserre F.
Published: May 2018

Water scarcity is mostly a man-made problem that increasingly affects people's lives and questions economic output in Northern China. Policy options addressing the serious water shortages in the region include conservation and water management reform, which is unpopular; grain imports and the downsizing of agriculture; derivation of Yangze water; derivation of the Amur and other international rivers. All solutions present major difficulties, whether domestic or international, for the Chinese authorities. While major decisions have not yet been taken, evidence shows major works such as water transfers from the Yangze or water pricing are not only unavoidable, but will not be enough to meet the growing demand for water in the region.
Operating feasibility of anaerobic whey treatment in a stirred sequencing batch reactor containing immobilized biomass
Authors: Ratusznei S.M. , Rodrigues J.A.D. , Zaiat M.
Published: May 2018

The scope of this work was to evaluate the operating feasibility of anaerobic whey treatment in a stirred sequencing batch reactor (ASBR) containing biomass immobilized on inert support. Assays were performed using 8-hour cycles and agitation rate of 200 rpm at 30 ± 1¡C, for treating cheese whey containing 500 to 4,000 mgCOD/L, which corresponded to a volumetric organic load (VOL) of 0.81 to 5.7 gCOD/L.d. Stability and high organic matter removal of about 96% were achieved at effluent concentration below 160 mgCOD/L for non filtered samples. Operating stability of the reactor was shown to be strongly dependent on the alkalinity supplementing strategy during the assay, especially during the startup period, where NaHCO3 supplementation was approximately 20Ð30% of the chemical oxygen demand (mgNaHCO3/mgCOD). After startup, alkalinity supplementation could be reduced down to 10% maintaining efficiency and stability. Moreover, proper homogenization of the system through mechanical agitation was also shown to be indispensable, especially with increasing organic load.
Assessment of compatible solutes to overcome salinity stress in thermophilic (55¡C) methanol-fed sulfate reducing granular sludges
Authors: Vallero M.V.G. , Lettinga G. , Lens P.N.L.
Published: May 2018

High NaCl concentrations (25 g.L-1) considerably decreased the methanol depletion rates for sludges harvested from two lab-scale sulfate reducing UASB reactors. In addition, 25 gNaCl.L-1 strongly affected the fate of methanol degradation, with clear increase in the acetate production at the expense of sulfide and methane production. The addition of different osmoprotectants, viz. glutamate, betaine, ectoine, choline, a mixture of compatible solutes and K+ and Mg2+, slightly increased methanol depletion rates for UASB reactors sludges. However, the acceleration in the methanol uptake rate favored the homoacetogenic bacteria, as the methanol breakdown was steered to the formation of acetate without increasing sulfate reduction and methane production rates. Thus, the compatible solutes used in this work were not effective as osmoprotectants to alleviate the acute NaCl toxicity on sulfate reducing granular sludges developed in methanol degrading thermophilic (55°C) UASB reactors.
Sequential anaerobic/aerobic biotreatment of bark leachate
Authors: Frigon J.C. , Cimpoia R. , Guiot S.R.
Published: May 2018

Bark leachate is generated from sawmill operations such as log storage sites and contains polymeric tannins, carbohydrates, organic acids, phenolic and resin compounds. The present study was aimed at assessing the performance of a sequential anaerobic and aerobic treatment, for both chemical oxygen demand (COD) and phenol removal, under various combinations of operational conditions, in the continuous mode. After anaerobic treatment in a five litres upflow anaerobic sludge bed (UASB) reactor, the leachate was directed into two parallel aerobic reactors, either an activated sludge unit or a fixed film submerged filter (packed with polyethylene Flexirings), both of a volume of one litre and oxygenated by air diffusion. For a leachate of 22 gCOD/l, an overall COD removal of 96Ð98% was achieved at an hydraulic residence time (HRT) of 4 days for the anaerobic reactor and one day for either aerobic systems. The phenol concentration generally increased after anaerobic treatment but was below the detection limit (50 ppb) after aerobic polishing. Radiorespirometric microcosms with 14C-labelled phenol confirmed that phenol was mineralized in the aerobic reactors. The performances of both aerobic systems were similar for COD and phenol removal. Thus, a sequential anaerobic/aerobic treatment was able to effectively address the contamination of a bark leachate discharge, including phenols.
Summary and conclusions from the SIWI Seminar for Young Water Professionals Water and sustainable development - how to ensure development without compromising sustainability?
Authors: Johannessen A.
Published: May 2018

There is a need to create a balance between development and conservation in order to find a way to mitigate the conflicting interests of water for society, the environment and the economy. Apart from finding a solution to this there is a need to get the message across to the decision makers. How do we make good ideas permeate policy and translate into concrete programs? The Young Water Professionals gave their view through presentations and discussions. It was argued that the answer was not to be found only in environmental science but also in the political and social arena. It was argued that the sanctioned discourse is a powerful force in water allocation and management. How can a balance be struck? Many argued for a unique design of a policy for the whole catchment, acknowledging ecology and existing institutions. Furthermore, many argued in favor of building on existing institutions and steward groups for sustainability and increase their adaptive capacity.
The influence of pH in the hydrolytic stage of anaerobic digestion of the organic fraction of urban solid waste
Authors: Dinamarca S. , Aroca G. , Chamy R. , Guerrero L.
Published: May 2018

The influence of the pH in the first stage, the hydrolytic stage, of the anaerobic digestion of the organic fraction of urban solid waste in a two phase anaerobic reactor was studied. The reactor was fed with a solution of the organic fraction of urban solid residues containing 5 to 7% solids. Four reactors with a working volume of 3 L were used, the experiments were done at three controlled pHs; 6, 7, and 8, and one with free pH, the temperature was keep at 37°C in all the experiments. The higher degradation of TSS and VSS was obtained in the reactors operated at pH 7 and 8; 75% degradation of TSS and 85% degradation of VSS. The volatile fatty acids were determined at the different pH conditions, no significant differences were found, and as was expected, the acetic acid was found at the higher value among them (from 25 to 29 g/L). According to the results obtained it is possible to conclude that in the case of the hydrolytic stage of the anaerobic digestion of the organic fraction of urban solid waste it is not necessary to control the pH, the pH is kept stable by the buffer effect of the protein residues and other macromolecules present in the residue.
Combined anaerobic-aerobic treatment of landfill leachates under mesophilic, submesophilic and psychrophilic conditions
Authors: Kalyuzhnyi S. , Gladchenko M. , Epov A.
Published: May 2018

As a first step of treatment of landfill leachates (total COD - 1,430-3,810 mg/l, total nitrogen 90-162 mg/l), a performance of laboratory UASB reactors has been investigated under mesophilic (30°C), sub-mesophilic (20°C) and psychrophilic (10°C) conditions. Under hydraulic retention times (HRT) of around 7 h, when the average organic loading rates (OLR) were around 5 g COD/l/day, the total COD removal accounted for 81% (on the average) with the effluent concentrations close to anaerobic biodegradability limit (0.25 g COD/l) for mesophilic and sub-mesophilic regimes. The psychrophilic treatment conducted under the average HRT of 8 h and the average OLR of 4.22 g COD/l/day showed a total COD removal of 47% producing the effluents (0.75 g COD/l) more suitable for subsequent biological nitrogen removal. All three anaerobic regimes used for leachate treatment were quite efficient for elimination of heavy metals (Fe, Zn, Cu, Pb, Cd) by concomitant precipitation in the form of insoluble sulphides inside the sludge bed. The application of aerobic/anoxic biofilter as a sole polishing step for psychrophilic anaerobic effluents was acceptable for elimination of biodegradable COD and nitrogen approaching the current standards for direct discharge of treated wastewater.
Land capability and topographic data as a surrogate for the mapping and classification of wetlands: a case example from the Daly basin, Northern Territory, Australia
Authors: Begg G. , Lowry J.
Published: May 2018

The Daly River (catchment 53,000 km2) has the largest flow of all rivers in the Northern Territory and, due to the vast underground aquifers supplying the river, reliable flows of water and areas of high potential soils, is the centre of a region where water resource and agricultural development is being given serious consideration. As part of a larger assessment of environmental flow requirements, an inventory and risk assessment of water dependent ecosystems (wetlands) was undertaken for the Daly basin, a limestone dominated region, 19,382 km2 in size, located in the centre of the catchment. The assessment utilized geographic information system technology to collate, interrogate and analyse soil and topographic data that had been collected previously for the purpose of land capability analysis. The aggregated data were used as a surrogate for mapping the distribution of wetlands in the Daly basin. The land units mapped were composed of individual areas within which the soil, vegetation and landform exhibited a uniform pattern on aerial photographs. The wetland features mapped were classified using landform and hydroperiod as a basis and, to assist in the classification process, a ground-truthing exercise and a basin-wide low-level aerial survey were conducted.
Modelling chloride-discharge relationships in Krishna river basin
Authors: Sekhar M.C. , Indira Ch.
Published: May 2018

Chloride discharge relationships at several monitoring stations on the River Krishna in South India are investigated, both qualitatively and quantitatively, to identify probable source contributions. The chloride behaviour along the waterway is studied in detail to assess the source contributions at various monitoring stations falling within the study area. Seasonal variations in the intensity of rainfall cause wide variations in the quality of the River Krishna. As there is strong seasonal dependence between the flow in the river and chlorides, seasonal models are developed for prediction of concentrations and loads. Linear regression analysis is carried out to determine the model parameters. The predicted concentrations and loads are in agreement with the observed values within the uncertainty of data. As the area is characterized by distinct dry and wet seasons (based on rainfall distribution over the year), mass balances are used to differentiate between point and non-point source contributions to the river. In large river basins, monitoring all individual sources is difficult and/or impossible and expensive; hence the presented approach based on receiving water quality and flow serves as an alternative for modeling chlorides in the river basin. Results of the study can be used to emphasise water pollution control strategies.
Derivation of a salinity target for the Lower Murray Darling Valley
Authors: Maini N. , Buchan A. , Joseph S.
Published: May 2018

The NSW Government commissioned catchment management boards (CMBs) to set the direction and process for catchment scale natural resource management. In the Lower Murray Darling, Rivers are highly regulated and water resources shared between three states. The Catchment Board only has jurisdiction over the northern bank of the Murray but salt and water enter the river from many locations upstream and along the area boundary. River salt and flow modelling has continually been improved to reflect and contribute to an increased understanding of salinity processes. The MDBC Salt Load study correlates 10 years of actual measured data with its modelled outputs, and estimates river salinities for 2020, 2050 and 2100. Routing models such as SALTFLO and MURKEY generate percentile salinity levels at different nodes in the River Murray downstream of the Lower Darling confluence.

National, Murray-Darling Basin and NSW salinity management policy and legislative requirements were considered, MDBC model output was used to ensure the interim targets are achievable, auditable, and appropriate to the catchment.

The method for an end-of-valley river based target for salinity is described. A target of less than 463 μS/cm for Lock 6, a point in the lower reaches of the Murray River is recommended for year 2010. Catchment management targets that express the main river salinity risk in five hydrologically distinct management zones are also recommended. Salinity management changes are needed in each zone to meet the end-of-valley target.
Response of Eucalyptus largiflorens to floodplain salinisation
Authors: Akeroyd M.D. , Walker G.R. , Kendall M.B.
Published: May 2018

An analysis of the stable isotopes from the tree rings of Eucalyptus largiflorens on the Chowilla Floodplain was undertaken. This chronology of tree water use responses was compared to the known hydrological changes that have occurred due to the effects of river regulation. The isotope chronology indicates that E. largiflorens has always oscillated between groundwater and rain-derived soil water and river regulation has apparently had little effect on tree water sources over time. This result is surprising, but no doubt reflects the complexity of floodplain processes and interactions between trees, water and the landscape.
Reality of irrigation water use and suggestions for better management: a comparison of two schemes from Sri Lanka
Authors: Wijesekera N.T.S. , Wickramaarachchi T.N.
Published: May 2018

In the dry zone of Sri Lanka, where agriculture is the main livelihood, both farmers and water managers target the best use of water. System H is an area that had been developed for irrigated agriculture using diversions from the River Mahaweli. Study of water use practices was carried out in two irrigation schemes where farmers cultivate the same crop in one-hectare allotments under the support and supervision of the same regional authority. Records of water use and agriculture are not well maintained. Using field visits, discussions with farmers, and meetings with officials were used to fill data gaps and three water issue scenarios were compared. Results of each scheme varied because water release and rotation practices for crop growth are quite different from each other, canal efficiency assumptions are different, land preparation, water use and quantity are dissimilar, and water releases do not consider much about growth stages. The study indicated that use of challenging water issues considering co-ordinated and rational grouping of canals could lead to a saving of 10–30 cm of water per unit area. A discussion of the need for a critical evaluation of guidelines and the present practice of cultivation is included.
Near surface water balance in the Northern Murray-Darling Basin
Authors: Vervoort R.W. , Silburn M. , Kirby M.
Published: May 2018

The water balance allows the calculation of deep drainage from other components of the hydrological cycle. Deep drainage has been linked to outbreaks of dryland and irrigated salinity. Until recently, deep drainage was not considered to be an issue on the alluvial plains of the Northern Murray-Darling Basin. Recent simulation studies and calculations using the water balance suggest that substantial deep drainage occurs under irrigated agriculture. However, these estimates have large uncertainties due to possible errors in measurement, calculation and due to spatial variability. On a catchment scale the relative area under a certain land use as well as the connection to local groundwater and the influence of anomalies such as prior streams needs to be considered. This paper discusses the current state of knowledge on the water balance in the Northern Murray-Darling Basin and highlights the need for a concentrated effort to measure all the components of the water balance in this area, as well as the effect on shallow groundwater quality and levels.
Biological phosphorus removal from a phosphorus-rich dairy processing wastewater
Authors: Bickers P.O. , Bhamidimarri R. , Shepherd J. , Russell J.
Published: May 2018

Dairy industry processing wastewaters consist mainly of dilutions of milk, milk products and cleaning solutions and, depending on the processes used, may be rich in phosphorus. In New Zealand and internationally, chemical removal of phosphorus is typically the phosphorus removal method of choice from dairy processing wastewaters. The enhanced biological phosphorus removal (EBPR) process was investigated in this study as an alternative phosphorus removal option using a continuous activated sludge system. A synthetic dairy processing wastewater was firstly subjected to fermentation in an anaerobic reactor (HRT = 12 hrs, pH = 6.5, temperature = 35°C) resulting in a fermented wastewater with an average volatile fatty acid (VFA) concentration of 1055 mg COD/L. The activated sludge reactor was operated in an AO configuration with an HRT of 2.5 days and an SRT of 15 days. Stable EBPR was exhibited with 42 mg P/L removed, resulting in a final sludge phosphorus content of 4.9% mg P/mg TSS. In the anaerobic zone (HRT = 2.85 hrs) the sludge had a phosphorus content of 3.16% mg P/mg TSS and a poly-β-hydroxyalkanoate (PHA) concentration of 86 mg COD/g TS.
Biomass accumulation patterns for removing volatile organic compounds in rotating drum biofilters
Authors: Yang C. , Suidan M.T. , Zhu X. , Kim B.J.
Published: May 2018

A rotating drum biofilter (RDB) with multi-layered foam media was developed for the improvement of current biofiltration technology. The biofilter was used to investigate the effects of organic loadings and influent volatile organic compound (VOC) concentrations on VOC removal efficiency and biomass accumulation. These effects were evaluated using diethyl ether and toluene separately as model VOCs at an empty bed contact time (EBCT) of 30 s. When the toluene loading increased from 2.0 to 4.0 and 8.0 kgCOD m-3 day-1, toluene removal efficiency of the biofilter decreased from over 99% to 78% and 74%, respectively. The biomass distribution was found to be more even within the medium when removing toluene than when removing diethyl ether. Higher organic loading also resulted in the more even distribution of the biomass. The ratios of biomass accumulation rates in the medium of the outermost, middle and innermost layers ranged from 1:0.11:0.02 when removing diethyl ether at 2.0 kgCOD m-3 day-1 to1:0.69:0.51 when removing toluene at 8.0 kgCOD m-3 day-1. Review of these ratios revealed three biomass accumulation patterns: surface pattern, in-depth pattern and shallow pattern. Different patterns represent different removal mechanisms in the biofiltration process. Improved biofilter design and operation should be based on the biomass accumulation pattern.
Estimation of stoichiometric and kinetic coefficients of ASm3 under aerobic and anoxic conditions via respirometry
Authors: Avcioğlu E. , Karahan-Gül Ö , Orhon D.
Published: May 2018

Activated Sludge Model No.1 (ASM1) has been used extensively for the design and simulation of biological treatment systems. Batch respirometric experiments have been described in the model for the determination of model coefficients and respirometric studies have been proved to be useful in kinetic parameter estimation and wastewater characterisation for ASM1. Activated Sludge Model No. 3 (ASm3) has also introduced a number of kinetic and stoichiometric coefficients with the new processes defined in the model, also suggesting some default values. Recent studies on the application of ASm3 are limited to special cases in terms of parameter determination. Proper calibration of ASm3 parameters can be a difficult task without involving respirometric procedures as experimental tools. Respirometric batch tests were conveniently used in this study in order to estimate ASm3 parameters and the main kinetic and stoichiometric model coefficients were successfully and uniquely determined for aerobic and anoxic conditions for acetate.
Improved process control with a pHauxostat for application in biotechnology
Authors: de Villiers G.H.
Published: May 2018

The pHauxostat is a unique control technique which was proposed nearly half a century ago but has found limited use up to date. This study highlights the results whereby the pHauxostat was analysed, categorized and a theory developed. pHauxostats can be categorised into Category A or B pHauxostats and further sub-divided into A1 or A2 and B1 or B2. The pHauxostat is successfully modelled by using alkalinity as a parameter whereby an alkalinity yield coefficient is defined. This alkalinity yield coefficient can be determined by applying half reactions, and together with traditional biological growth models the process can be described theoretically. This enables the applications of the technique in a predictable and controlled way with the possibility of wider use. The technique can be described as a self-regulating control technique in biotechnology whereby the pH is used as the controlled output variable and the feed (rate and/or concentration) the manipulated input variable.
Effect of oxygen on the stability and inducibility of the biodegradative capability of benzoate
Authors: Çinar Ö , Deniz T. , Grady C.P.L.
Published: May 2018

Anoxic zones in biological nitrogen removal systems are typically open to the atmosphere and receive oxygen from the atmosphere and the recirculation flow from the aerobic zone. This raises the question of how such oxygen input might influence the stability and inducibility of the enzyme systems involved in biodegradation of aromatic compounds. To investigate this, various amounts of oxygen were added to mixed culture denitrifying chemostats receiving benzoate at 667 mg/h as chemical oxygen demand (COD), and the stability and inducibility of the culture’s benzoate biodegradative capability (BBC) were tested in aerobic and anoxic fed-batch reactors (FBRs). Cultures from chemostats receiving oxygen at 0, 33, 133, 266, and 466 mg O2/h lost almost all of their anoxic BBC within one hour after being transferred to an aerobic FBR and the first three cultures did not recover it upon being returned to anoxic conditions. The last two cultures recovered their anoxic BBC between 9 and 16 h during the 16 h aerobic exposure period that preceded their return to anoxic conditions and continued to increase their anoxic BBC as they were retained under anoxic conditions. In contrast, the culture from a chemostat receiving oxygen at 67 mg O2/h retained its anoxic BBC longer, recovered it within 3 h after its return to anoxic conditions, and increased it linearly thereafter. None of the cultures developed any aerobic BBC during the 16 h aerobic exposure period in FBRs. The results suggest that higher oxygen inputs into anoxic reactors helped the mixed microbial cultures recover and/or induced anoxic BBC more easily when they were exposed to alternating aerobic/anoxic environments. The exceptional behavior of the culture from the chemostat receiving oxygen at a rate of 67 mg O2/h may have been caused by the presence of a protective mechanism against the toxic forms of oxygen.
Numerical modelling of the petroleum oil penetration into sandy beach sediments
Authors: Sagehashi M. , Miyagishi A. , Kose T. , Nishijima W. , Okada M.
Published: May 2018

A numerical model describing the penetration of petroleum oil into sandy beach sediments was developed to assess the behavior of stranded oil at tidal zone as a result of tanker accidents, and so on. To understand the penetration behavior, penetration rate of three species of petroleum oil (two species of fuel oil C and one species of crude oil) was observed experimentally with artificial tidal zone equipment. As a consequence, two types of oil were distinguished from the viewpoint of penetration rate. One (fuel oil C-1) kept its homogeneity in composition and showed relatively rapid penetration, the other (fuel oil C-2 and crude oil) became heterogeneous and slow in penetration. Considering this aspect as the adsorption of the polar compounds (i.e. asphaltenes) on the sediment surface, a numerical model that described oil penetration into sandy beach was developed. As a result, the difference in penetration rate between these two types of oil could not be replicated sufficiently only by consideration of the adsorption. However, the change of a parameter value which represents the apparent viscosity of oil led to good agreement with observations. Simulation results indicated that when fuel oil C or crude oil used in this study was stranded at a sandy beach located in Hiroshima Bay, Japan, 2 to 39% of total stranded oil might penetrate into the deeper zone (>3 cm in depth) over 50 days.
Integrated water quality management for drinking water of good quality
Authors: Isaji C.
Published: May 2018

The Nagoya Waterworks and Sewerage Bureau has developed original supporting tools for the systematic and cost-effective management of problem solving. An environmental information map and prediction of pollutant reaching are used for rapid and appropriate proper countermeasures against water quality accidents in the source area. In disinfection byproduct control a method for estimating trihalomethane (THM) contents was effective for the complement of their observations. Surrogate indicators such as turbidity and conductivity that could be measured continuously also could complement water quality items measured monthly. A processing tool of voluminous data was practical for rapid judgment of water quality. Systematic monitoring was established for stricter turbidity control for measures against Cryptosporidium and keeping residual chlorine stable in the service area.
Cold climate BMPs: solving the management puzzle
Authors: Oberts G.L.
Published: May 2018

Snowmelt runoff and rain-on-snow events present some of the highest pollutant loading and most difficult management challenges in the course of a year in regions with cold climate. Frozen conduits, thick ice layers, low biological activity, altered chemistry, and saturated or frozen ground conditions all work against effective treatment of melt runoff. Understanding the source, evolution and transition that occurs within a melt event, and defining the management objectives for specific receiving waters will help focus the search for effective management techniques. Solving the management puzzle means putting together a strategy for both soluble and solids-associated water pollutants.
Increased chloride concentration in a lake due to deicing salt application
Authors: Thunqvist E.-L.
Published: May 2018

During winter, the Swedish National Road Administration uses on average 250,000 tonnes of sodium chloride for deicing purposes. Chloride concentration is a function of the amount of deicing salt applied during the winter season and the amount of water in which the salt can be diluted. An estimation of seasonal amount of deicing salt in relation to amount of run-off was used in order to identify the effects of deicing salt. The measured chloride concentration in a lake used as a municipal water supply was similar to the concentration estimated by a simple steady state method accounting for the catchment area. The simplified steady state method was a useful tool for estimating steady state concentrations on a regional level, including a non-influenced lake as a comparison.
Siting, design and operational controls for snow disposal sites
Authors: Wheaton S.R. , Rice W.J.
Published: May 2018

The Municipality of Anchorage (MOA), at 61° north latitude, ploughs and hauls snow from urban streets throughout the winter, incorporating grit and chloride applied to street surfaces for traffic safety. Hauled snow is stored at snow disposal facilities, where it melts at ambient spring temperatures. MOA studies performed from 1998 through 2001 show that disposal site melt processes can be manipulated, through site design and operation practices, to control chloride and turbidity in meltwater. An experimental passive “V-swale” pad configuration tested by MOA investigators reduced site meltwater turbidity by an order of magnitude (to about 50 NTU from the 500 NTU typical of more conventional planar pad geometry). The MOA has developed new siting, design and operational criteria for snow disposal facilities to conform to the tested V-swale pad configuration.
Electrochemical pilot scale study for reduction of 2,4-DNT
Authors: Doppalapudi R. , Palaniswamy D. , Sorial G. , Maloney S.
Published: May 2018

An electrochemical pilot scale reactor was used to treat simulated munitions wastewater containing 100 mg/L of 2,4-dinitrotoluene (DNT). Experiments were conducted by using a glassy carbon (zero porosity) coated graphite cylinder as the cathode and a platinum wire as the anode. All experiments were conducted under dissolved oxygen concentration of less than 1.5 mg/L. Initially, experiments simulating batch conditions were conducted to obtain the optimum operating conditions for the reactor. During this batch-mode study, the effects of various parameters such as applied current, electrolyte concentration, and type of electrolyte on the reduction of DNT were evaluated. Results obtained showed that the rates of reduction of DNT increased with an increase in current or concentration of electrolyte. Based on the results obtained from the batch simulation experiments, continuous flow experiments were conducted at three different currents. The ionic strength of the feed solution was maintained at 0.027 M. A current of 200 mA was found to provide a stable reduction of DNT at the 80% level for a period of 14 days after which reactor cleaning is necessary for removal of solids that were formed within the reactor. End products determined for the continuous flow experiments showed 100% molar balance conversion.
Developing risk-based screening guidelines for dioxin management at a Melbourne sewage treatment plant
Authors: Gorman J. , Mival K. , Wright J. , Howell M.
Published: May 2018

Dioxin is a generic term used to refer to the congeners of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The principal source of dioxin production is generally thought to be from unintended by-products of waste incineration, but dioxins are also naturally formed from volcanic activity and forest fires (WHO, 1998). Estimates of dioxin emissions in Australia suggest that approximately 75% of the total PCDD and PCDF emissions derive from prescribed burning and wild bushfires. Currently, no screening guidelines for dioxins within soils are available in Australia. This paper presents the general approach and results of a human health risk-based assessment performed by URS Australia in 2001 to develop site specific reference criteria for remediation of a former sewage treatment plant in Melbourne. Risk-based soil remediation concentrations for dioxins at the sewage treatment plant site were developed using tolerable daily intake values of 4, 2 and 1 pg/kg/day. The potentially significant exposure pathways and processes for exposure to dioxins were identified and risk-based soil concentrations derived in accordance with the general method framework presented in the National Environmental Protection Measure (Assessment of Site Contamination). The derived dioxin reference criteria were used to develop an effective risk management program focussed on those conditions that present the greatest contribution to overall risk to human health.