bluuebunny/crossref_metadata_2025 huggingface dataset:
Nutrient removal in subsurface flow constructed wetlands for application in sensitive regions
Authors: Rustige H. , Platzer Chr.
Published: May 2018

One of the most interesting sites for research on CWs in Germany has been established in Wiedersberg (Saxonia). The multi-stage concept with primary settling, vertical and horizontal flow reed bed followed by UV-disinfection and a special phosphorus filter bed, allows numerous ways of operation and investigations. Denitrification can be improved by recirculation through VF bed and sedimentation tank or by means of adding carbonaceous water from the primary stage to a second level within the VFB or directly to the following HF bed. In order to investigate the efficiency of P-elimination four kinds of natural sands containing different amounts of iron have been used. To maintain a long-term capacity for P-reduction an additional filter bed is filled with gravelly sand which had been used for the precipitation of iron from drinking water before. After saturating with P this filter medium can be exchanged easily.

A result of more than one year of operation is the high performance rate for adsorption of phosphorus by enriched iron on drinking water filter sand. At a total loading rate of 350 g P/m3 filter medium 250 g P/m3 have been adsorbed. Design considerations can not be given yet. The median denitrification rate at VFB is 1.3 g N m-2d-1 and at HFB is 0.25 g Nm-2d-1. The low denitrifcation rate of HFB might be due to a very high quota of wastewater dilution by storm- and ground-water of 100 to 200 percent. The investigations on this wastewater treatment plant will be continued until June 2001 and experiments with filter columns will be added.
Application of constructed wetlands for wastewater treatment in Nepal
Authors: Shrestha R.R. , Haberl R. , Laber J. , Manandhar R. , Mader J.
Published: May 2018

Surface water pollution is one of the serious environmental problems in urban centers in Nepal due to the discharge of untreated wastewater into the river-system, turning them into open sewers. Wastewater treatment plants are almost non-existent in the country except for a few in the Kathmandu Valley and even these are not functioning well. Successful implementation of a few constructed wetland systems within the past three years has attracted attention to this promising technology. A two-staged subsurface flow constructed wetland for hospital wastewater treatment and constructed wetlands for treatment of greywater and septage is now becoming a demonstration site of constructed wetland systems in Nepal. Beside these systems, five constructed wetlands have already been designed and some are under construction for the treatment of leachate and septage in Pokhara municipality, wastewater in Kathmandu University, two hospitals and a school. This paper discusses the present condition and treatment performance of constructed wetlands that are now in operation. Furthermore, the concept of the treatment wetlands under construction is also described here. With the present experience, several recommendations are pointed out for the promotion of this technology in the developing countries.
The integration of constructed wetlands into a treatment system for airport runoff
Authors: Revitt D.M. , Worrall P. , Brewer D.
Published: May 2018

A new surface runoff treatment system has been designed for London Heathrow Airport, which incorporates separate floating constructed wetlands or reedbeds and sub-surface flow constructed wetlands as major pollutant removal systems. The primary requirement of the newly developed treatment system is to control the concentrations of glycols following their use as de-icers and anti-icers within the airport. The ability of reedbeds to contribute to this treatment role was fully tested through pilot scale, on-site experiments over a 2 year period. The average reductions in runoff BOD concentrations achieved by pilot scale surface flow and sub-surface flow reedbeds were 30.9% and 32.9%, respectively. The corresponding average glycol removal efficiencies were 54.2% and 78.3%, following shock dosing inputs. These treatment performances are used to predict the required full scale constructed wetland surface areas needed to attain the desired effluent water quality. The treatment system also incorporates aeration, storage and, combined with reedbed technology, has been designed to reduce a mixed inlet BOD concentration of 240 mg/l to less than 40 mg/l for water temperatures varying between 6°C and 20°C.
Treatment of laboratory wastewater in a tropical constructed wetland comparing surface and subsurface flow
Authors: Meutia A.A.
Published: May 2018

Wastewater treatment by constructed wetland is an appropriate technology for tropical developing countries like Indonesia because it is inexpensive, easily maintained, and has environmentally friendly and sustainable characteristics. The aim of the research is to examine the capability of constructed wetlands for treating laboratory wastewater at our Center, to investigate the suitable flow for treatment, namely vertical subsurface or horizontal surface flow, and to study the effect of the seasons. The constructed wetland is composed of three chambered unplanted sedimentation tanks followed by the first and second beds, containing gravel and sand, planted with Typha sp.; the third bed planted with floating plant Lemna sp.; and a clarifier with two chambers. The results showed that the subsurface flow in the dry season removed 95% organic carbon (COD) and total phosphorus (T-P) respectively, and 82% total nitrogen (T-N). In the transition period from the dry season to the rainy season, COD removal efficiency decreased to 73%, T-N increased to 89%, and T-P was almost the same as that in the dry season. In the rainy season COD and T-N removal efficiencies increased again to 95% respectively, while T-P remained unchanged. In the dry season, COD and T-P concentrations in the surface flow showed that the removal efficiencies were a bit lower than those in the subsurface flow. Moreover, T-N removal efficiency was only half as much as that in the subsurface flow. However, in the transition period, COD removal efficiency decreased to 29%, while T-N increased to 74% and T-P was still constant, around 93%. In the rainy season, COD and T-N removal efficiencies increased again to almost 95%. On the other hand, T-P decreased to 76%. The results show that the constructed wetland is capable of treating the laboratory wastewater. The subsurface flow is more suitable for treatment than the surface flow, and the seasonal changes have effects on the removal efficiency.
Metals in combined conventional and vegetated road runoff control systems
Authors: Pontier H. , Williams J.B. , May E.
Published: May 2018

Combined conventional and vegetated runoff treatment systems were installed on the rural Newbury Bypass in Southern England, which was estimated to carry an average daily traffic of 30,000 vehicles. The system components were arranged in series to give progressive pollutant removal, comprising an oil separator, sediment trap, grassy slope and constructed wetland. In the absence of specific design criteria for road runoff control, the system design was based on available guidance notes. Since the road opened, an 18-month monitoring programme has examined the performance of these systems. Early indications are that the systems, and especially the wetlands, promote removal of suspended solids (>1.2 μm) and effectively trap fine (<63 μm) sediments. The waters were generally oxidising with neutral to basic pH which may have favoured metal partitioning to the solid phase. The distribution pattern for Zn and Cu in fine sediments contrasted in two of the systems studied, indicating the complex behaviour of metals in wetlands. Further work will increase the data set and examine the adsorption behaviour of metals. These results will contribute to the development of future design criteria for the application of wetlands to road runoff treatment.
Nitrogen and phosphorus variation in shallow groundwater and assimilation in plants in complex riparian buffer zones
Authors: Kuusemets V. , Mander Ü , Lõhmus K. , Ivask M.
Published: May 2018

The study of purification efficiency and nutrient assimilation in plants was made in two riparian buffer zones with a complex of wet meadow and grey alder (Alnus incana) stand. In the less polluted Porijõgi test site, the 31 m wide buffer zone removed 40% of total nitrogen (total-N) and 78% of total phosphorus (total-P), while a heavily polluted 51 m wide buffer zone in Viiratsi retained 85% of total-N and 84% of total-P. The input of nutrients and purification efficiency displayed a significant relationship. The total-N removal in buffer zone was negative when the input value was less than 0.3 mg l-1 and the purification efficiency was always positive when the input value exceeded 5 mg l-1. The purification efficiency of total-P was positive when the input value exceeded 0.15 mg l-1. Grass vegetation plays an important role in nutrient retention in riparian buffer strips. The maximum phytomass production was measured in Porijõgi site where production of the Filipendula ulmaria community was up to 2,358 g m-2, assimilation of N 32.1 and of P 4.9 g m-2, respectively. This is much higher than the biomass production and N and P uptake of the grey alders (Alnus incana) at the same site - 1,730, 20.5 and 1.5 g m-2, respectively.
The effect of pH on enterococci removal in Pistia-, duckweed- and algae-based stabilization ponds for domestic wastewater treatment
Authors: Awuah E. , Lubberding H.J. , Asante K. , Gijzen H.J.
Published: May 2018

A batch scale experiment was conducted to determine the effect of pH on enterococci die-off. A continuous flow system was also established to determine the environmental conditions and their effects on enterococci removal. The batch experiment was conducted for pHs: 4, 5, 7, 9, and 11 under light and dark conditions. Enterococci and DO were measured every day and every other day respectively for nine days. Pathogen removal rates at pH 4, 5, 7, 9 and 11 in the light/dark were (expressed as d-1) -2.1/-2.1, -2.1/-1.5, -2.1/-1.5, -2.1/-1.4 and -1.1/-1.0, respectively. DO levels were low, between 0.17 mg/L at pH 4 (light) to 0.56 mg/L at pH 7 (light). The continuous flow system consisted of Pistia (water lettuce), duckweed and algal treatments in series of four ponds with a total retention period of 28 days after two days of anaerobic pre-treatment. After two months of operation, temperature, pH, DO, TDS, and enterococci populations were monitored. A low pH of 4.4 was obtained in the Pistia ponds. Neutral conditions were observed in the duckweed system, while pH values >9 were observed in the algal system. Enterococci decreased from 7.8×106 to <500/100 ml in all treatment systems after 28 days of treatment with no significant differences between treatments.
Accounting for the spatial rainfall variability in urban modelling applications
Authors: Williams P. , Berlamont J.
Published: May 2018

In hydrological and hydrodynamic modelling of urban catchments, the spatial variability of rainfall is often neglected. This spatial variability encloses two aspects: (1) the spatial variability of the statistical properties of rainfall, and (2) the non-uniform spatial distribution of rainfall over the modelled catchments. In an ongoing research project for the Ministry of the Flemish Community (Belgium), the influence of this spatial rainfall variability on the results of modelling applications is studied. At the same time, most efficient methods to reduce this influence are determined. The results of the research can be applied directly in Flanders. They consist of a combination of unified IDF-relationships, spatial correction factors (generally applicable formulas), a stochastic simulation model for spatial rainfall (software) and a methodology for improving the spatial correction factors in a case-specific way by performing simulations with the model.
Stochastic generation and disaggregation of hourly rainfall series for continuous hydrological modelling and flood control reservoir design
Authors: Hingray B. , Monbaron E. , Jarrar I. , Favre A.C. , Consuegra D. , Musy A.
Published: May 2018

In the urban environment, stormwater detention basins are a powerful means to limit the frequency of sewer system failures and consecutive urban flooding. To design such waterworks or to check their efficiency, it is possible to carry out continuous rainfall-runoff modelling. A long-term discharge series obtained from a long-term rainfall series is used as input for a storage model describing the detention basin behaviour: the basin behaviour may be consequently studied over a long period. The provided statistical information on the working state frequency, failure frequency, … of the detention basin is of high interest for the basin diagnostic or for its design. This paper presents the whole methodology which leads to production of such statistical information and especially: the models used to generate long term rainfall series with a short time step, the rainfall-runoff model used to transform the later series into a long term discharge series, and the model used to describe the behaviour of the detention basin. This methodology was applied to evaluate the efficiency of 4 detention basins built for stormwater control and flood mitigation. They are situated on a Swiss urban catchment (Chamberonne catchment – 40 km2) collecting water from the Mèbre and Sorge rivers.
Monitoring faecal contamination of the Thames estuary using a semiautomated early warning system
Authors: Tryland I. , Surman S. , Berg J.D.
Published: May 2018

The Colifast Early Warning System, based on measuring β-galactosidase activity (2 h method), was evaluated for monitoring the level of faecal contamination in the upper tidal Thames. Two trials were performed, one following heavy rain in November 2000, the next during a dry and sunny period in July 2001. In general the b-galactosidase activity and the two coliform reference methods (recovery following membrane filtration with membrane lauryl sulphate broth (MLSB) and Colilert™ Quantitray) were comparable. However, in several samples in July the β-galactosidase activity seemed to overestimate the number of culturable coliforms, suggesting that the rapid enzymatic method detected β-galactosidase produced by other bacterial sources, such as Aeromonas spp. or Vibrio spp., or nonculturable coliforms. The latter could be attributed to sunlight-induced injury. Nevertheless, the rapid method based on β-galactosidase activity gave an estimate of the level of culturable coliforms, which did not differ from both coliform reference methods by more than one log. Monitoring of β-galactosidase activity in river water samples using the Colifast Analyser may therefore be useful as an early warning indicator of faecal contamination.
Risk-based modeling of early warning systems for pollution accidents
Authors: Grayman W.M. , Males R.M.
Published: May 2018

An early warning system is a mechanism for detecting, characterizing and providing notification of a source water contamination event (spill event) in order to mitigate the impact of contamination. Spill events are highly probabilistic occurrences with major spills, which can have very significant impacts on raw water sources of drinking water, being relatively rare. A systematic method for designing and operating early warning systems that considers the highly variable, probabilistic nature of many aspects of the system is described. The methodology accounts for the probability of spills, behavior of monitoring equipment, variable hydrology, and the probability of obtaining information about spills independent of a monitoring system. Spill Risk, a risk-based model using Monte Carlo simulation techniques has been developed and its utility has been demonstrated as part of an AWWA Research Foundation sponsored project. The model has been applied to several hypothetical river situations and to an actual section of the Ohio River. Additionally, the model has been systematically applied to a wide range of conditions in order to develop general guidance on design of early warning systems.
Application of recombinant fluorescent mammalian cells as a toxicity biosensor
Authors: Kim E.J. , Lee Y. , Lee J.E. , Gu M.B.
Published: May 2018

With respect to developing a more sensitive biosensor, a recombinant fluorescent Chinese Hamster Ovary cell line was used for the monitoring of various toxicants. Both cell lines, EFC-500 and KFC-A10, were able to detect toxicants sensitively. They were characterized with mitomycin C and γ-ray as genotoxicants and bisphenol A, nonylphenol, ziram and methyl bromide as possible and known EDCs. When compared to each other, the response of KFC-A10 was generally more informative and sensitive. Compared to typical bacterial biosensor systems, these cell lines offered a sensitivity of 2- to 50-fold greater for the tested chemicals. Based on these results, the use of mammalian cells offers a sensitive biosensor system that is not only fast, cheap and reproducible but also capable of monitoring the endocrine-like characteristics of environmental toxicants.
Erosion mechanisms in combined sewers and the potential for pollutant release to receiving waters and water treatment plants
Authors: Mcllhatton T.D. , Sakrabani R. , Ashley R.M. , Burrows R.
Published: May 2018

The problems associated with solids in sewerage systems result in common difficulties such as blockages and flooding and the subsequent maintenance requirements have been well documented. Concerns regarding pollutant release have also been demonstrated, with the contribution from in-sewer solids to the quality of the flow during a storm event being especially significant. These events known as “foul flushes” in combined sewers typically occur in the initial period of storm flows, when the concentration of suspended sediments and other pollutants are significantly higher than at other times. Traditionally impacts from these events have been related to the suspended solids phase of the flow passing through a CSO structure. It is now apparent that much of the suspended load originates from solids eroded from the bed. The “near bed solids” which are re-entrained into the flow, together with solids eroded from the bulk bed, account for large changes in the suspended sediment concentration under time varying flow conditions. The influence of these eroded solids and their potential impact on receiving waters and treatment plants will be reviewed using data obtained from field studies carried out in the main Dundee interceptor sewer in Scotland. This paper describes some of the methods employed to investigate the characteristics of the pollutants associated with solids erosion in combined sewers.
Surface and subsurface irrigation with effluents of different qualities and presence of Cryptosporidium oocysts in soil and on crops
Authors: Armon R. , Gold D. , Brodsky M. , Oron G.
Published: May 2018

A large variety of human pathogens are excreted in wastewater including bacteria, viruses, protozoan cysts and helminth eggs. In raw sewage, human pathogens reach high numbers, thereafter decreasing successively at each treatment step. However, the final effluents still contain a large fraction of these pathogens that may pose a serious public health. Among the various crops irrigated with effluents, vegetables are the most vulnerable to contamination. Vegetables, usually eaten raw (uncooked) or with rich dressings (causing regrowth of some pathogenic bacteria) pose the main threat to humans. The importance of microbiological and parasitological criteria for reused water has been repeatedly emphasized. Some microbiological recommendations based on epidemiological data have been established for untreated wastewater, there is still a need to define the criteria for effluent quality required for unrestricted crop irrigation. This paper presents a field study comparison of two irrigation methods: surface and subsurface of field crops (mainly vineyard) and follow-up of Cryptosporidium oocysts in soil at different depths (0 to 90 cm). Oocysts were isolated at all depths without a clear pattern of distribution (0 to 640 oocysts/g). In addition different vegetables irrigated with different effluent qualities were tested for the presence of Cryptosporidium oocysts and Giardia cysts. The highest prevalence of oocysts was found on zucchini that has a sticky and hairy outer surface (80 to 10,000 oocysts/0.5 kg).
Probabilistic emission and immission modelling: case-study of the combined sewer – WWTP – receiving water system at Dessel (Belgium)
Authors: Willems P. , Berlamont J.
Published: May 2018

The impact of the combined urban drainage and WWTP system of the village of Dessel (Belgium) on the Witte Nete receiving water is modelled both in terms of emissions and immissions. The hydrodynamic and water quality modelling is performed both in a deterministic and probabilistic way. For the deterministic modelling, detailed physically based and simplified conceptual models are used in a complementary way. In the probabilistic modelling, the different uncertainties in the deterministic model are classified in input uncertainties, parameter uncertainties and model-structure uncertainties. The probabilistic simulation results can be used in risk analysis and management, for the determination of the major uncertainty-sources and priorities in model improvement, for model bias elimination and for efficient model calibration.
A practical application of integrated urban pollution modelling in Flanders (Belgium): the catchment of Tielt
Authors: Van Assel J. , Carrette R.
Published: May 2018

In view of a European Innovation Project (DG XIII) on the application of the Urban Pollution Management (UPM) procedure, a European consortium was set up to carry out pilot studies in Belgium, France, Ireland, Italy and Portugal. On the Belgian pilot catchment of Tielt the impact from sewer system and sewage treatment plant (STP) on the receiving water courses was studied for both the existing situation and for a number of possible improvement schemes, using the Intermittent Standards, described in the UPM procedure. The integrated modelling revealed some interesting conclusions on the relative impact of the schemes considered.
Sewer losses and interactions with groundwater quality
Authors: Ellis J.B. , Revitt D.M.
Published: May 2018

Inflow/infiltration (I/I) and infiltration/exfiltration (I/E) are interactive processes which dynamically affect sewer and groundwater performance. The incidence and condition of “critical” sewers in the UK are identified together with chemical and bacterial methods of quantifying I/E and its potential impact on sewer performance and on urban groundwater pollution. Whilst the impacts of I/E do not appear to be substantial on the basis of existing evidence, some caution is advocated in respect of long term sewer sustainability.
Effects of real time control of sewer systems on treatment plant performance and receiving water quality
Authors: Frehmann T. , Niemann A. , Ustohal P. , Geiger W.F.
Published: May 2018

Four individual mathematical submodels simulating different subsystems of urban drainage were intercoupled to an integral model. The submodels (for surface runoff, flow in sewer system, wastewater treatment plant and receiving water) were calibrated on the basis of field data measured in an existing urban catchment investigation. Three different strategies for controlling the discharge in the sewer network were defined and implemented in the integral model. The impact of these control measures was quantified by representative immission state-parameters of the receiving water. The results reveal that the effect of a control measure may be ambivalent, depending on the referred component of a complex drainage system. Furthermore, it is demonstrated that the drainage system in the catchment investigation can be considerably optimised towards environmental protection and operation efficiency if an appropriate real time control on the integral scale is applied.
Performance of partially separate sewer systems and impacts on receiving waters
Authors: Ferreira F.M. , Matos J.S. , Rodigues A.C. , do Monte H.M.
Published: May 2018

The aim of this document is to present and discuss the results of the experimental work undertaken in Laje stream, in a section near the village of Oeiras in Portugal. The work was developed with the main objective of characterising stormwater quality in Portuguese drainage systems, and to predict the effects of the performance of partially separate sewer systems on receiving waters. For this purpose, volume and characteristics of stormwater carried by a partially separated sewer system were estimated, both in terms of flow and Chemical Oxygen Demand (COD) loads. The study also analyses the eventual implementation of non-conventional solutions, as a way of reducing problems of bacteriological contamination of seawaters. This aspect is particularly important in Portugal, where the population is mainly concentrated in urban areas located down-stream of important drainage basins, close to the coastline. Therefore, sanitary sewer overflows discharging directly into receiving waters are frequent, with possible consequences in terms of bacteriological contamination of bathing areas. Based on experimental research and available data it was possible to collect informations regarding stormwater average COD and overflow coliform loads, and the occurrence of first flush effects.
Wastewater COD characterization: biodegradability of physico-chemical fractions
Authors: Ginestet P. , Maisonnier A. , Spérandio M.
Published: May 2018

Physico-chemical and biological characterization methods were applied to wastewater samples originating from 7 French WWTPs. The settleable fraction (S), unsettleable-coagulable fraction (US-C) and unsettleable-uncoagulable fraction (US-UC) were separated. Special emphasis was put on the determination of hydrolysis kinetics associated with coagulable- and settleable-fractions in order to model their behaviour in activated sludge processes, as both these fractions are influenced by the SRT. The “soluble” fraction (i.e. US-UC) was composed of readily biodegradable COD (2 to 27%), readily hydrolysable COD (37 to 90%) and inerts (2 to 47%). The “colloidal” fraction (i.e. US-C) was composed of heterotrophic biomass (9 to 24%) and readily hydrolysable COD (6 to 82%), with the rest being inerts or very slowly biodegradable COD (0 to 70%). The “particulate” fraction (i.e. settleable) was composed of biomass (14 ± 6%), readily hydrolysable COD (21 ± 14%), slowly hydrolysable COD (about 45–50%) and 15 to 20% which can be considered as inert matter (XI). “Readily hydrolysable COD” was correctly modeled by a global first-order reaction. First-order constants (KH) were 9 ± 2 d−1 for raw-wastewater, 12 ± 3 d−1 for primary settled-wastewater and 16 ± 5 d−1 for coagulated-wastewater. “Slowly hydrolysable COD” was correctly modeled by a limited surface reaction. Concerning this fraction, the specific hydrolysis rate (kH) ranged from 0.25 to 1.05 d−1, and the affinity constant (KX) ranged from 0.33 to 0.95 gCOD/gCOD based on settleable solids analysis.
A practical protocol for dynamic modelling of activated sludge systems
Authors: Hulsbeek J.J.W. , Kruit J. , Roeleveld P.J. , van Loosdrecht M.C.M.
Published: May 2018

Use of dynamic simulation models has become standard practice in The Netherlands. Since the introduction around 5 years ago more then 100 full scale wastewater treatment plants have been modelled. Initially very different approaches have been used varying in calibration approach, amount of sampling and time investment. Based on the accumulated practical experiences the Dutch Foundation of Applied Water Research STOWA has stimulated the development of a protocol to aid in the set-up and calibration of models for full scale wastewater treatment plants. Herein the aim was to develop a protocol, which in practice was easy to use, minimising time and costs effort, but give a reliable and useable method. In this paper this protocol is briefly described.
The planning and construction of an urban stormwater management scheme
Authors: Lloyd S.D. , Wong T.H.F. , Porter B.
Published: May 2018

Water Sensitive Urban Design (WSUD) offers a means to integrate stormwater best management practices into urban planning and design to achieve multiple objectives. Some of these objectives relate to stormwater drainage, water quality improvements, aquatic habitat protection, stormwater harvesting and use, and landscape amenity. The Lynbrook Estate, Australia, has incorporated bio-filtration systems and wetlands into the design of major roads, local access streets and parklands that attenuate and treat roof runoff and road runoff from a 32 ha, 270 allotment residential precinct. This paper outlines the process that enabled the concept of a stormwater drainage design to be translated into on-ground works. Details of the construction activities, costs and market acceptance highlight the potential for the adoption of similar practices elsewhere.
Developing, evaluating and maintaining a standardized stormwater BMP effectiveness database
Authors: Clary J. , Urbonas B. , Jones J. , Strecker E. , Quigley M. , O'Brien J.
Published: May 2018

The Urban Water Resources Research Council of the American Society of Civil Engineers, under a cooperative agreement with the US Environmental Protection Agency, released Version 1.0 of the National Stormwater Best Management Practices (BMP) Database to the stormwater management community in 1999. The product included a loaded database of 71 BMPs, as well as data entry software for standardized reporting of BMP test data. In conjunction with the database, the project team developed BMP performance evaluation protocols and applied them to the data contained in the initial database. Since the initial database release, 42 new BMP data sets have been added to the database, which is now accessible via the Internet at www.bmpdatabase.org along with associated data evaluation reports and other project documentation. A national stormwater BMP data clearinghouse continues to screen and post new BMP data to the database, as well as respond to inquiries from the public. An overview of both of the database software and results of the data evaluation are provided in this paper.
Numerical and experimental investigations of the pollutant distribution in sewers
Authors: Jaumouillié P. , Larrarte F. , Milisic V.
Published: May 2018

Controlling flow and pollutant discharges through sewer networks is required for a number of reasons. In order to accomplish such control, precise knowledge of the hydrodynamic conditions of each candidate measurement location proves critical. The Laboratoire Central dos Ponts et Chaussés has thus become involved in an experimental program on velocity and suspended matter concentration fields. This paper first presents the measurement methods and experimental results obtained before providing and discussing some of the numerical results.
Polishing of secondary effluent by an algal biofilm process
Authors: Schumacher G. , Sekoulov I.
Published: May 2018

The potential in polishing secondary effluent by an algal biofilm composed of different green and bluegreen algae was investigated. During the photosynthesis process of algal biofilm oxygen was produced while dissolved carbon dioxide was consumed. This led to an increasing pH due to the change of the carbon dioxide equilibrium in water. The high pH caused precipitation of dissolved phosphates. The attached algae took up nitrogen and phosphorus during the growth of biomass. In addition to nutrient removal, an extensive removal of faecal bacteria was observed probably caused by adsorption of the algal biofilm and by photo-oxidation involving dissolved oxygen. The experimental results suggest that a low-cost, close to nature process especially for small wastewater treatment plants for nutrient removal and bacteria reduction can be developed with the aid of an algal biofilm.
SOIL and SOIL-NO at catchment scale – a case study for an agriculture-dominated catchment
Authors: Deelstra J. , Bechmann M. , Kvaernø S.H.
Published: May 2018

A one-dimensional model, SOIL/SOIL-NO, is used to simulate the water and nitrogen balance at catchment scale. The objective is to use the model in simulating the effects of best management practices on nitrogen runoff. The model was applied to individual farm fields in an agriculture dominated catchment and simulations were carried out for the period from 94–98. The results were promising. The simulated nitrogen runoff agreed quite well with the measured nitrogen loss at the main station. The effects of best management practices like optimal fertiliser application, catch crops and irrigation were simulated. For this particular catchment, the introduction of catch crops resulted in the best effect on reducing nitrogen runoff from agricultural dominated catchments.
Comparison of field measurements to predicted reaeration coefficients, k2, in the application of a water quality model, QUAL2E, to a tropical river
Authors: Mohamed M. , Stednick J.D. , Smith F.M.
Published: May 2018

Some of the many tools used for watershed management are mathematical and computer models for wasteload allocations. QUAL2E is one of the most popular water quality models used for such purposes. The question arises as to whether the model is applicable in a different climate such as that in the tropics. In this study, QUAL2E was used to model Sg. Selangor River in Malaysia using the predictive equations for reaeration coefficient (k2) within the model and the measured reaeration coefficients for the river. The study results indicated that use of the reaeration coefficient (k2) measured at Sg. Selangor River did give the lowest standard error (SE) for the simulation of water quality during the 7Q10 low-flow period which is considered as the worst scene scenario in water quality modeling. But during calibration and validation using actual low-flow discharge data, the measured reaeration coefficients did not give the lowest standard error (SE). In conclusion, the results indicated that QUAL2E is applicable in tropical rivers when used with the modeled river parameters (i.e. hydraulic parameters, meteorological conditions etc.). Measured reaeration coefficients produced good results and several predictive equations also produced comparatively good results.
Fluorescence technique for the characterization of natural organic matter in river water
Authors: Ahmad U.K. , Ujang Z. , Yusop Z. , Fong T.L.
Published: May 2018

The complex nature of natural organic matter (NOM), and the impact of this matter on drinking water quality have necessitated the characterization studies of NOM. A fluorescence technique for the characterization of NOM in Malaysian river water is reported. Water samples from several river sampling sites were collected and concentrated using a low-pressure reverse osmosis (LPROM). Solid phase extraction (SPE) using C18 extraction cartridges were used to fractionate the water samples into humic and non-humic fractions. To differentiate and classify various types of humic substances, fluorescence was applied in emission, excitation and in synchronous-scan modes. A synchronous spectral profile was found to be able to differentiate humic and fulvic acids better than the emission or excitation spectra. Synchronous excitation spectra showed different spectral patterns for the water samples due to different origin. All water samples showed the presence of both fulvic and humic acids.
Runoff characteristics of particulate pesticides in a river from paddy fields
Authors: Inoue T. , Ebise S. , Numabe A. , Nagafuchi O. , Matsui Y.
Published: May 2018

Runoff characteristics of particulate pesticides from paddy fields have been intensively observed in the Koise River in Japan. The 8 pesticides that are applied to paddy fields were analyzed in both particulate and dissolved forms. The concentrations and the detection frequencies of particulate pesticides were lower than those of dissolved pesticides. The particulate pesticide concentrations in the river water were evaluated based on the soil sorption coefficient, particulate organic carbon concentration, and dissolved pesticide concentrations. The particulate pesticide concentrations in the river were higher than evaluated concentrations because the paddy soil contained more pesticides than did suspended solids in the river water discharged during rain events, and because the desorption rates of pesticides were slow. In observations made during rains, the particulate pesticide concentrations increased with the increases in both the discharge rate and the concentrations of suspended solids. The particulate loading was slight compared with dissolved loading, but particulate pesticides may be influenced by enclosed areas such as a lake or estuary because under such conditions particulate matter settles vertically and the pesticide decomposition rate in sediment is slow compared with that in water.
Elaboration of a complex GIS application in a catchment area
Authors: Németh T. , Szabó J. , Pásztor L. , Bakacsi Zs.
Published: May 2018

Rearrangement of land resources after political changes has not yet been finished in Hungary. It is almost impossible to collect information necessary for planning activities on outer areas of settlements. The data are distributed among various organizations and can be found in diverse forms or there are no available data at all. However water quality protection has become legally ordered concerning municipal activities around Lake Balaton which is considered as the most important recreation area and tourist target in Hungary and is also affected by a number of factors providing sources of environmental conflicts. Settlements in a catchment area (Tetves Creek) on the southern shoreline of Lake Balaton in Central Hungary tendered a complex project for collecting sources of authentic data of the Hungarian rural areas along with systematizing and saving these data in a uniform GIS. An application using Autodesk MapGuide Program for Internet realization was developed. The implemented web-based system can be used in Internet and Intranet environments.
Evaluation of efficiencies of diffuse allochthonous and autochthonous nutrient input control in restoration of a highly eutrophic lake
Authors: Muhammetoğlu A. , Muhammetoğlu H. , Soyupak S.
Published: May 2018

Mogan Lake is an important recreational area for Metropolitan Ankara-Turkey. It is a shallow eutrophic lake with a dense growth of macrophytes. The main contributors of nutrients and other pollutants to the lake are the creeks carrying the runoff water from the watershed and upland farming land, in addition to the domestic and industrial wastewater discharges from a nearby town and industries. Hydrodynamic and water quality modeling techniques were used to determine the optimum management schemes for the lake restoration and diffuse pollution control. Management scenarios were devised and tested to control allochthonous and autochthonous nutrient inputs to the lake. Phosphorus and nitrogen load reductions were the main test elements for the control of allochthonous nutrient inputs. The scenario analysis revealed that reduction of phosphorus and nitrogen loads from diffused sources will have a marginal effect on controlling eutrophication if macrophyte growth is left uncontrolled. Scenarios employing macrophyte harvesting and sediment dredging have been evaluated for autochthonous nutrient input control. Sediment dredging alone has been shown to yield the most favorable conditions for water quality improvement in Mogan Lake. Further, control of diffuse pollution was an essential final step to achieve an acceptable long-term sustainable water quality improvement in the lake.
Application of an automatic sampling and measurement system to a mountainous stream investigation during rain events
Authors: Komai Y. , Umemoto S. , Inoue T.
Published: May 2018

An automatic sampling and measurement system was developed to take water samples efficiently during rain events. The system consisted of an automatic sampler, a rain gauge and a data logger as well as sensors for pH, electrical conductivity (EC), and both water and air temperature. The system was tested in a stream in a forested watershed (5.8 km2) located in the middle of Hyogo prefecture, Japan. The sampling program has been improved gradually. For several rain events of 30 to 157 mm, most water samples were in agreement with the hydrograph from the beginning of each rainfall until the rain had stopped and the water level had begun to fall. The fluctuations in water quality in the samples taken by the automatic sampler during those rain events showed patterns similar to those of water samples taken by hand. There were also no problems with the water level or the EC sensor during the investigation periods, but the pH values were lower than those in the laboratory. The results showed that the system is suitable for taking water samples from mountainous streams during rain events.
Performance of an extended aeration - microfiltration (EAM) reactor in treating high strength industrial wastewater
Authors: Noor M.J.M.M. , Muyibi S.A. , Ahmed T. , Ghazali A.H. , Jusoh A. , Idris A. , Ahmadun F.R. , Nagaoka H. , Aya H.
Published: May 2018

A laboratory study was conducted on an Extended Aeration - Microfiltration (EAM) reactor in treating a food industry wastewater. The reactor contained horizontally laid hollow fibre microfiltration (MF) units that were fully submerged. The MF units were connected to a peristaltic pump that was used to extract permeate continuously under suction pressure. Continuous aeration from beneath the modules provided the crossflow effect to the MF units. Active activated sludge was used in the start-up where the sludge was mixed together with the feed water at a Food/Microorganisms (F/M) value of about 0.1. Primary effluent with Chemical Oxygen Demand (COD) values ranged between 1,500 and 3,000 mg/l was used as feed water. The EAM reactor was operated for nearly three months without initiating cleaning of the MF units. A suction pressure of 0.9 bar and Mixed Liquor Suspended Solids (MLSS) of over 5,500 mg/l were reached when nearing the end of the three month operation period. Permeate COD and turbidity reduction of over 97% and 99% respectively, were achieved. Prior to this, the MF module arrangements were studied; where vertically arranged modules were found to perform poorly as compared to the horizontally laid modules, in terms of clean water permeate flux.
Comparison of the quantity and quality of the microbiological content of sludge in countries with low and high content of pathogens
Authors: Jimínez B. , Maya C. , Sãnchez E. , Romero A. , Lira L. , Barrios J.A.
Published: May 2018

The parasites present in the residual sludge generated by the diverse treatment processes of residual water vary, depending on the socioeconomic and epidemiological conditions of different communities. And although data exist at the global level regarding the microbiological quality of sludge, these data are practically nonexistent in developing countries. Therefore, this project compares the content of the four principal groups of parasites in residual sludge from the United States and Mexico. The marked differences between the orders of magnitude found in the two countries (coliphages 103-106 and 1.3 × 105 PFU/gTS, fecal coliforms 107-1010 and 107, Salmonella typhi 106-108 and 103 MPN/gTS, Giardia lamblia 102-104 and 102 cysts/gTS and helminth ova from 73-177 and <1 to 10 viable HO/gTS, respectively) will permit proposing real, effective and economical stabilization processes (undoubtedly different from those of industrialized countries), and will thus take advantage of the benefits represented by the reuse and disposal of sludge, in addition to developing regulations in agreement with the conditions of each region.
Molecular and conventional analyses of microbial diversity in mesophilic and thermophilic upflow anaerobic sludge blanket granular sludges
Authors: Sekiguchi Y. , Kamagata Y. , Ohashi A. , Harada H.
Published: May 2018

The microbial community structure of mesophilic (35°C) and thermophilic (55°C) methanogenic granular sludges was surveyed by using both cultivation-independent molecular approach and conventional cultivation technique in order to address the fundamental questions on the microbial populations, i.e. who are present, where they are located, and what they are doing there. To elucidate the microbial constituents within both sludges, we first constructed 16S ribosomal DNA clone libraries, and partial sequencing of the clones was conducted for phylogenetic analysis. In this experiment, we found a number of unidentifiable clones within the domain Bacteria as well as clones that were closely related with 16S rDNAs of cultured microbes. The unidentifiable clones accounted for approximately 60–70% of the total clones in both mesophilic and thermophilic libraries. 16S rRNA-targeted in situ hybridization combined with confocal laser scanning microscopy was subsequently employed to examine where the uncultured populations were located within sludge granules. Spatial organization of uncultured microbes was visualized in thin-sections of both types of granules using fluorescent oligonucleotide probes, which were designed based on the clone sequences of certain novel clusters. This resulted in the detection of two types of uncultured cells in specific locations inside the granules. Finally, the goal-directed conventional cultivation technique was employed to recover such uncultured anaerobes and uncover their physiology and functions. In this approach, a total of five new species of thermophilic microorganisms were isolated, including several types of syntrophs and a novel sugar-fermenting bacterium. In the previous molecular approaches, all of these isolates were suggested to be significant populations within thermophilic granular sludge, hence obtaining these isolates in pure culture decreased the fraction of unknown clones in the previous thermophilic clone library from 70% to 40%. In conclusion, these approaches successfully revealed biodiversity and spatial organization of microbes of interest in sludge granules, and enlarged the fundamental knowledge of microbial constituents functioning as significant populations in the UASB processes.