bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparing sludge production under aerobic and anoxic conditions
Authors: Copp John B. , Dold Peter L.
Published: May 2018

The results of 32 batch tests demonstrate a significant difference in biomass yield under anoxic and aerobic conditions using a variety of soluble substrates. An anoxic yield of 0.402 mg particulate COD/mg consumed COD was calculated which is 62% of the corresponding aerobic yield of 0.645 mg particulate COD/mg consumed COD. Batch tests were performed under anoxic and aerobic conditions using a seed of either activated sludge from one of two local municipal wastewater treatment facilities or a prepared sample of Pseudomonas denitrificans. Irrespective of the test organism, the calculated yields were consistent for each electron acceptor. A novel approach to quantifying the consumption of electron acceptor was employed in these batch tests. COD balance calculations were performed and confirmed that all of the initial COD could be accounted for in terms of residual soluble COD, biomass production and electron acceptor consumption.
Generation of halogenated organic compounds in municipal waste water
Authors: Schulz Stefanie , Hahn Hermann H.
Published: May 2018

Cleaning agents and disinfectants from housekeeping, hospitals and canteen kitchens are important sources of adsorbable halogenated organic compounds (AOX) in municipal waste water. They often contain inorganic compounds which are able to release activated chlorine. Together with organic waste water compounds the activated chlorine can generate halogenated organic compounds. Within the scope of this research project the generation of AOX through these active agents is compared. The effects of concentration, pH, time, temperature, presence of other oxidizing or reducing agents and synergetic effects are investigated and discussed.

According to the results the potential of these active agents forming AOX is obvious. The AOX concentration of a municipal waste water increased by the factor of 13 after adding hypochlorite containing disinfectant in common concentration. Most AOX can be formed within 30 minutes. In sewage with high amount of solid compounds the AOX generation can take a long time (several days). The amount of AOX generated strongly depends on the nature and concentration of dissolved and solid organic compounds, the concentration of active substances, temperature, pH and the reaction time.
Real time control of the sewer system of boulogne billancourt - a contribution to improving the water quality of the seine
Authors: Entem Stéphane , Lahoud Antoine , Yde Lars , Bendsen Bo
Published: May 2018

Confronted with the problem of overflows from its combined sewer system into the River Seine during rainfall, the Department of the Hauts de Seine (which covers some thirty urban districts on the west side of Paris) has decided to implement the real time control of its sewer system. To initiate this plan, as the town of Boulogne Billancourt seemed to be a particularly favourable site for the use of such techniques, a project to control its sewer system in real time has been implemented within the scope of the SPRINT 226 programme financed by the European Community.

The preliminary studies, based on a MOUSE computer model of the sewer system, showed that the real time control of the sewer network under study had a high potential benefit, since it would allow an 80% reduction of the volumes of waste water discharged into the Seine annually in the study zone. Following on from these encouraging results, the installation of a complete real time control system was set in hand. The system, at present undergoing testing and evaluation, consists principally of a MOUSE ON LINE real time model and a system for forecasting rainfall by means of radar images.
An integrated approach for improving the wastewater discharge and treatment systems
Authors: Pfister A. , Stein A. , Schlegel S. , Teichgräber B.
Published: May 2018

Since treatment plants have been built all over Germany during the last decades, the water quality of receiving streams has been improved remarkably. But there are still a lot of quality problems left, which are caused e.g. by combined sewer overflows (CSO), treatment plant effluents or rainwater discharges from separate sewer systems. At present different efforts are undertaken to control sewer systems in order to improve the operation of urban drainage systems or more generally, design processes. The Emschergenossenschaft and Lippeverband (EG/LV) are carrying out research studies, which are focusing on a minimization of total emissions from sewer systems both from wastewater treatment plant (WWTP) effluents and from CSO. They consider dynamic interactions between rainfall, resultant wastewater, combined sewers, WWTP and receiving streams. Therefore, in an advanced wastewater treatment, a model-based improvement of WWTP operation becomes more and more essential, and consequently a highly qualified operational staff is needed. Some aspects of the current research studies are presented in this report. The need and the use of an integrated approach to combine existing model components in order to optimize dynamic management of combined sewer systems (CSS) with a benefit for nature are outlined.
Uni-directional freezing of sewage sludge
Authors: Chu C. P. , Lee D. J.
Published: May 2018

A vertical freezing test on sewage sludge is conducted in this work. The sludge is placed in sample tubes immersed vertically into a freezing pool, whence the ice front grows upwards at a constant freezing speed. If the sludge is completely frozen, regardless of the freezing speed, the sludge filterability is markedly improved. However, the associated sludge settleability and the final sediment height will not alter much except when gross migration of flocs takes place.
Classification of algogenic organic matter concerning its contribution to the bacterial regrowth potential and by-products formation
Authors: Schmidt Wido , Hambsch Beate , Petzoldt Heike
Published: May 2018

The bacterial regrowth potential (BRP) and the by-products formation potential after the disinfection (DBP) are parameters recognized to be influenced by the origin of organic matter dissolved in water. A significant difference of the impact of humic compounds and algogenic organic matter (AOM), characteristic for raw waters from reservoirs, to both parameters can be assumed. In systematic laboratory experiments the influence of AOM on the BRP as well as DBP was examined. Different fractions of the AOM were chlorinated and treated with chlorine dioxide. In addition to that the influence of the ozonation was investigated. To assess the biodegradable fraction of the organic matter (BDOC) a large spectrum of by-products (aldehydes and keto-acids) was analyzed. The BRP in the water was determined by the measurement of the increase of biomass in the water samples. It could be proved, that the chlorination of intact algae cells containing waters may cause a significant increase of the biodegradability in the water if the residual chlorine is totally required. In the case of the disinfection of the AOM containing waters with chlorine dioxide the relative increase of the BRP was lower in comparison to the chlorinated waters. The preozonation of the algae containing waters indicates an additional increase of the BRP, but only by ozonation of the algae cells. The ozonation of the algae metabolites does not influence the BRP, but it causes a significant decrease of the THM-formation if chlorine is used for disinfection.
Effect of biomanipulation on the structuring of the planktonic food web and water treatability by coagulation
Authors: Hejzlar J. , Dolejš P. , Komárková J. , Sed′a J. , Šimek K. , Vyhnálek V.
Published: May 2018

The impact of planktivorous fish on the plankton community structure and character of aquatic organic matter was studied by a meso-scale enclosure experiment in a stratified reservoir. Aims of the study were (i) to examine the response of the communities with and without herbivorous zooplankton to an increased input of phosphorus and (ii) to determine the composition and coagulation properties of the organic matter produced by these communities. The concentration and composition of organic matter were affected both in the enclosure with planktivorous fish (F), where high algal biomass developed, and in the enclosure without fish (Z), where algae were maintained at a low concentration by zooplankton grazing. Although differences between the enclosures in concentrations of total dissolved organic matter and its hydrophobic, hydrophilic and neutral/basic fractions were relatively small, coagulation properties of the organics differed substantially. Particulate and dissolved organic matter produced in enclosure F had a positive effect on the efficiency of alum coagulation in contrast to the less readily separable organics produced in enclosure Z. The results indicate that pelagic food web manipulations to maintainin low phytoplankton biomass by zooplankton grazing may not always have positive effects on the treatability of water by coagulation.
Aerobic stabilisation criteria for BNR biosolids
Authors: Tonkovic Zlatko
Published: May 2018

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

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

The objective of the research program was to quantify the degree of stabilisation achieved in various activated sludge treatment plants, what additional aerobic treatment is required to achieve a stabilised sludge and what are the readily identified characteristics of a stabilised sludge, including volatile solids content, specific oxygen uptake rate and pathogen destruction. The phosphorus leaching characteristics were also compared between various sludges and between continuous and intermittent aerobic digestion process.
Accumulation of freshwater red tide in a dam reservoir
Authors: Yamada Masato , Ono Yoshiro , Somiya Isao
Published: May 2018

The distribution and biomass of Peridinium bipes f. occultatum were observed in the autumns of 1991, 1992 and 1994 at the head of the Shorenji Dam reservoir (Mie prefecture, Japan). Summarizing observations and some other information, we discussed processes related to the accumulation of Peridinium biomass. In the study area, biomass of Peridinium increased at a similar rate to growth day by day, and roughly 2/3 of the daily maximum biomass fluctuated in a given day. The horizontal ‘import’ and ‘export’ of Peridinium biomass by flows mainly change the biomass of red tide at the upstream end of the reservoir. Flow control in the reservoir, as well as growth control, will also be important in suppressing freshwater red tide.
BEKWAAM, a model fit for reservoir design and management
Authors: Benoist A. P. , Brinkman A. G. , van Diepenbeek P. M. J. A. , Waals J. M. J.
Published: May 2018

In the Province of Limburg in the Netherlands a new reservoir will be used for the drinking water production of 20 million m3 per annum from the rear 2002. With the use of this reservoir the WML is shifting towards the use of surface water (River Meuse) as primary source instead of ground water. This in view of the general Dutch policy pertaining to desiccation abatement and ground water pollution control. Because the River Meuse is known to be polluted with various numbers of constituents, predominantly nutrients, and on occasion with heavy metals and pesticides, the reservoir water quality model BEKWAAM has been constructed to be able to predict the water quality of this reservoir. The model simulates processes like heating, decay, sedimentation and eutrophication. The model was calibrated using data of two existing reservoirs in the Netherlands. The first simulation results of BEKWAAM indicate that significant high temperature differences are expected between river water and reservoir water, a point to be dealt with in the design of the inlet construction, to prevent stratification. Furthermore is was concluded that, providing thorough mixing takes place, the average depth of 20 m of this new reservoir induces sufficient light limitation. Finally the expected ammonium-nitrogen concentrations will not exceed a value of 0.05 mg NH4-N/l, despite the fact that average River Meuse concentration ranges from 0.1–1.7 mg NH4-N/l. This is caused by processes like nitrification and uptake by algae.
Managing the threats of afforestation in reservoir catchments
Authors: Stretton Chris
Published: May 2018

Until recently the development of forestry sites in the United Kingdom paid little regard for their impact on the aquatic environment, with the result that there have been several instances of major damage to drinking water reservoirs, two of which are described briefly. In order to improve the formal planning of future forestry work the water industry initiated development of a joint Working Group, with the objective of producing Guidelines for use throughout the forest industry. Development of these Guidelines are described, as is the basic content of the final document which now forms an important reference work for the industry, both for the development of new forest sites and for restocking following felling of the first rotation. Concerns remain regarding the continuing management of sites, particularly with regard to artificial fertilisation and its potential to encourage algal blooms in standing waters: close liaison will be necessary between water and forestry interests.
Short term effects of dissolved oxygen concentration on the turbidity of the supernatant of activated sludge
Authors: Wilén Britt-Marie , Balmér Peter
Published: May 2018

Short term effects of dissolved oxygen (DO) concentration on the supernatant turbidity of activated sludge were studied in batch reactors, continuous reactors and in a full scale plant. Adsorption of colloidal material onto activated sludge was studied in batch reactors. The adsorption capacity of colloidal material, expressed as removal of turbidity, was larger in aerobic than in anaerobic conditions. The difference in adsorption capacity between high (≥5 mg/l) and low (<0.5 mg/l) DO concentrations was small. Experiments were made in pilot scale completely mixed reactors where the oxygen supply was turned off during different periods of length (1-4 hours). The turbidity increased directly when the anaerobic period started and decreased when the aerobic period started. Similar results were obtained when the influent was turned off. A few full scale experiments were carried out. The aerators were adjusted to change the DO concentration along the aeration tank (plug flow) for periods of 3-6 hours. Low DO concentrations by the end of the aeration tank produced a turbidity increase of the effluent, while low DO concentrations in the first half of the aeration tank did not affect the turbidity to a large extent.
Phosphorus uptake and active growth of Elodea canadensis Michx. and Elodea nuttallii (Planch.) St. John
Authors: Eugelink A. H.
Published: May 2018

Two related submerged freshwater macrophyte (Elodea nuttallii (Planch.) St. John and Elodea canadensis Michx.) were used in a combination of in- and outdoor experiments to compare growth rates and routes of phosphorus uptake, translocation and possible excretion. Elodea nuttalli had a higher growth rate than Elodea canadensis both in the field and under laboratory conditions.

The uptake and translocation of phosphorus was studied using 32P in a partitioned container. Roots and leaves were supplied with 32P separately and simultaneously. Both macrophyte species were able to take up phosphorus both with leaves and roots. The uptake rate of 32P by roots was higher in Elodea nuttallii when tracer was supplied to the root compartment only. Leaf uptake was stimulated by the supply of phosphate to both compartments, and the uptake was faster and reached a higher level than when the tracer was injected to the leaf compartment only. The 32P uptake by either roots or leaves was translocated. Shoot-to-root translocation predominated over the reverse. There was no significant difference between both species in root uptake rates, but leaf uptake was significantly higher in Elodea canadensis. The two studied Elodea species do not have a strong preferential source of phosphorus.
Gordona scum suppression mechanism of ozone added in wastewater treatment plants
Authors: Goi M. , Odagawa K. , Nishimura T. , Okoch T. , Yuzawa H.
Published: May 2018

In order to prevent the scum generation due to Gordona (Nocardia) amarae, experiments were made to add ozone in the aeration tank from 1990 to 1994, and scum suppression effects, sludge settleability improvement effects, etc. were reported. The studies made so far did not clarify the scum suppression mechanism of added ozone. Based on the measurements of the number of Gordona, mycolic acid, etc., an attempt was made to investigate this mechanism. By adding ozone, the number of Gordona was suppressed in general to below 1 × 105 CFU/mg-SS. In the presence of mycolic acid produced by Gordona amarae at a rate of about 178-236 μg in 1g activated sludge, no scum generation was seen. Within an experimental range of ozone added at a rate below 3 mg/l, it was considered that the scum suppression effect was due more to the decomposition of mycolic acid, which is a metabolite of Gordona amarae, than to the effect of the number of Gordona amarae being reduced by the disinfectant action of ozone.
Monitoring cations to predict and improve activated sludge settling and dewatering properties of industrial wastewaters
Authors: Murthy Sudhir N. , Novak John T. , De Haas Robert D.
Published: May 2018

Laboratory and field tests were conducted on activated sludge from an industrial wastewater treatment plant in order to monitor the settling and dewatering properties and to assess the impact cations may have on these properties. The influent to the wastewater treatment plant contained a high concentration of sodium ions and a low concentration of divalent cations. The sludge exhibited poor settling and dewatering properties. Initial laboratory results indicated an improvement in settling and dewatering properties through the addition of calcium and magnesium. After addition of magnesium during field trials, floc density and settling properties improved considerably. In addition, residual ammonium ions in the mixed liquor appeared to interact with the activated sludge flocs to influence their dewatering properties. It was observed that an increase in ammonium ion in the soluble sludge fraction was related to deterioration in the dewatering properties. During these trials, the ammonium ions demonstrated a greater influence on dewatering properties than did the magnesium ions. The tests conducted at the treatment plant revealed that complex interactions between cations and sludge influenced the settling and dewatering properties in a manner that depended on ratios and concentrations of monovalent and divalent cations in the activated sludge feed and solution.
Experiments on high rate effluent filtration in the Netherlands
Authors: van der Graaf Jaap H. J. M. , van Nieuwenhuijzen Arjen F.
Published: May 2018

As yet, filtration of wastewater treatment effluent has not been practised in the Netherlands. The main objections were the expected high costs. In order to gain practical experience an investigation programme studied the applicability and optimization of effluent filtration. Especially multi-layer filtration with the addition of ironchloride seemed to be very effective. Very low concentrations of suspended solids and phosphorus were achieved, even at high filtration rates (up to 30 m/h). This leads to an impressive reduction of expected costs, down to Dfl. 0.02/m3 (treated water).
Rule based control of a periodic activated sludge process
Authors: Isaacs S. , Thornberg D.
Published: May 2018

A rule based control strategy for automatically adjusting phase lengths and aeration intensity for an activated sludge nutrient removal process based on a periodic operation is examined using simulations based on the Activated Sludge Model No. 1. The strategy is based on four criterion functions, two which determine the switching of the roles of two nitrifying/denitrifying reactors and two which adjust the dissolved oxygen setpoint levels in the two reactors as functions of ammonia and nitrate concentrations. Trajectory plots of reactor concentrations in the ammonia-nitrate plane are shown to be a useful means of visualizing process and control performance. Together, the trajectories from a working region in the ammonia-nitrate plane, the size and location of which can to some extent be predetermined by selection of the criterion functions. The presented results include the influence of one of the criterion functions on control strategy performance, how an incompatibility between two criterion functions can lead to unsymmetric reactor loading, and the effect of allowing simultaneous nitrification and denitrification during nitrifying periods by reducing the dissolved oxygen level as ammonia is consumed.
“Appropriate technology” for pollution control in corrugated board industry - the Portuguese case
Authors: Duarte E. A. , Neto I. , Alegrias M. , Barroso R.
Published: May 2018

An increasing number of countries can be considered as water-stressed. Portugal is facing this problem, associated with the guarantee of an adequate water supply. Increasing costs of municipal and industrial disposal for water quality protection and pollution reduction also catalyse interest in water reuse. This paper presents a case study in the corrugated board industry, where advanced strategies were followed, in order to implement a totally integrated waste management system, through the selection of the appropriate technology, avoiding environmental damage. The results obtained were the establishment of an optimal balance between the main strategy elements, evaluated on the basis of environmental load, preservation of resources and economy.
Relative importance of the phenomena responsible for chlorine decay in drinking water distribution systems
Authors: Kiéné L. , Lu W. , Lévi Y.
Published: May 2018

Free chlorine consumption in distribution systems is due both to chemical reactions occurring in the bulk phase and at the pipe walls. Knowledge of the relative importance of these various reactions is needed in order to improve chlorine decay modeling. Experimental results carried out in this study make it possible to propose a hierarchical classification of the main parameters involved in the free chlorine decay observed in distribution systems. Corrosion of metallic pipe appears to be a major parameter, while synthetic materials are of little influence. The rate of chlorine decay in bulk phase can be estimated according to the TOC and the temperature. Influence of biofilms depends on the BDOC content of water, and on the pipe diameter. Chlorine decay due to corrosion phenomena must be modeled according to a zero order kinetics, while chlorine decay due to other parameters can be modeled according to a first order kinetics with respect to chlorine.
Evaluation of Canadian drinking water guidelines using probability modeling of population exposure
Authors: Kindzierski W. B. , Jackson L. G.
Published: May 2018

An evaluation of potential population exposure to benzene in drinking water and in indoor air was conducted in an attempt to consider the adequacy of the allowable level set for benzene in Canadian drinking water (5 μg/l). Exposure factors representative of the Canadian adult population; including tapwater and beverage-based tapwater consumption, body weights, time spent inside residences, and levels of benzene in residential air; were assessed using the method of Monte Carlo probability modeling. Rates of benzene exposure from consumption of drinking water were estimated to be lower than from inhalation of indoor air by up to a factor of ten for almost half of the adult population when the drinking water concentration was represented by the allowable level. With respect to human exposure, 5 μg/l of benzene in drinking water would not contribute significantly to exposure that is already estimated to occur from breathing air inside their homes for almost half of the adult population. On that basis the drinking water level would appear more than adequate for public health protection. However, Canadian agencies may need to pay greater attention to exposure to benzene in residential air, as no similar criteria or monitoring programs exist to protect the public.
Biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) under nitrate-reducing conditions
Authors: Freedman David L. , Sutherland Kevin W.
Published: May 2018

Hexahydro-1,3,5-trinitro-1,3,5-triazine is a widely used military explosive that is more commonly known as Royal Demolition Explosive (RDX). Because of concerns with the potential toxicity of RDX, increasingly stringent regulations are anticipated for wastewater discharges from munitions manufacturing facilities. At the Holston Army Ammunition Plant (HAAP), where RDX is currently produced in the U.S., the treatment sequence includes an anoxic filter prior to aerobic filters and activated sludge reactors. The intent of the anoxic filter is to remove the high levels of nitrate that are often present in munitions wastewater, as well as RDX and other nitrated energetic compounds. However, RDX removal across the filter is typically not adequate to meet the anticipated regulatory target, and RDX tends to persist under aerobic conditions. The objective of this study was to evaluate the reason for poor RDX removal in the anoxic filter. Microcosms were set-up with HAAP wastewater and biofilm scraped from the anoxic filter. Nitrate-reducing conditions were readily established, with organics present in the wastewater as well as acetate serving as electron donors. However, as long as nitrate was present, no decrease in RDX (15 μM) occurred. As soon as nitrate was depleted and some primary substrate was still available, RDX was rapidly biotransformed to metabolites that included mononitroso, dinitroso, and trinitroso derivatives. The disappearance of nitrate, followed by biotransformation of RDX, coincided with a decrease in redox potential to below −200 mV. These results were confirmed with an ethanol-grown nitrate-reducing enrichment culture that was inoculated with biofilm from the HAAP anoxic filter. The presence of RDX had no apparent effect on nitrate reduction, whereas RDX biotransformation was completely inhibited until all of the nitrate was consumed. Nitrate removal was achieved by repeated additions of ethanol. Thus, in order to ensure efficient biotransformation of RDX, nitrate removal must be complete, which requires an electron donor supply that exceeds the acceptor capacity of the nitrate.
Mass transfer limitation in PAH-contaminated soil remediation
Authors: Yeom Ick-Tae , Ghosh Mriganka M.
Published: May 2018

Batch experiments were conducted to determine the effects of Triton X-100, a nonionic phenolic ethoxylate surfactant, on the biodegradation of soil-bound naphthalene and phenanthrene. Two different types of soils, one contaminated with polynuclear aromatic hydrocarbons (PAHs) for different lengths of time, 2 days to 10 months, in the laboratory and the other, a field-contaminated soil from a manufactured gas plant (MGP) site, were used. Biodegradation of PAHs was measured by monitoring the 14CO2 production for the artificially contaminated soils and the residual PAHs in soil phase for the MGP soil. Without adding surfactant, the mineralization rate of phenanthrene was significantly smaller in the 1 0-month contaminated soil compared to that in the 2-day contaminated soil. Presumably, mineralization was mass-transfer limited in the soil with longer contamination period. Triton X-100 significantly enhanced mineralization in the 10 month-old soil but none in the 2-day old soil. The MGP soil, weathered over 2-3 decades, exhibited even greater enhancement of mineralization. Mineralization of PAHs in aged soils appears to be controlled by mass transfer rather than the rate of biodegradation. Surfactants increase the rate of release of soil-bound contaminant and thus help promote biodegradation.
Potential of mono- and bimetallic catalysts for liquid-phase hydrogenation of aqueous nitrite solutions
Authors: Pintar A. , Batista J. , Levec J.
Published: May 2018

Liquid-phase reduction using a solid catalyst provides a potential technique for the removal of nitrites from waters. Activity and selectivity measurements were performed for a wide range of reactant concentrations and reaction conditions in an isothermal semi-batch slurry reactor operating at atmospheric pressure. The effects of catalyst loading and initial nitrite concentration on the reaction rate were also investigated. The Pd monometallic catalysts were found to be advantageous over the Pd-Cu bimetallic catalyst with respect to both reaction activity and selectivity. Minimum ammonia formation was observed for the Pd(1 wt. %)/γ-Al2O3 catalyst. The reaction kinetics was found to be dependent on the catalyst surface hydroxylation, which has also been confirmed by runs conducted in a continuous-flow monolith reactor.
Radiation induced pollutant decomposition in water
Authors: Gehringer P. , Matschiner H.
Published: May 2018

Two sets of experiments are described, one dealing with the radiation induced decomposition of some volatile chlorinated solvents in deionized water using electron beam irradiation with and without addition of ozone, the other dealing with γ-irradiation of aqueous peroxodisulfate solutions for OH free radical generation. It was found that the radiation induced decomposition of 10 mg/L 1,1,1-trichloroethane in deionized water is not improved by addition of ozone. Accordingly the resulting dose requirement for decomposition is too high for a technical application. No difference was recorded for the radiation induced decomposition of 10 mg/L trichloroethylene (TCE) as well as 10 mg/L perchloroethylene (PCE) in deionized water with and without addition of ozone. These results deviate from previous results obtained in groundwater. Ozone addition reduced the dose requirements in a way that could be of interest for technical application. Based on the assumption of a 25 kW mobile electron beam accelerator a technical design is discussed that would result in a capacity for the destruction of 10 t PCE/a. The results of some experiments performed with the combination peroxodisulfate/γ-irradiation to decompose benzene as well as 1,4-dioxane dissolved in tap water did not really recommend this combination for a technical use.
An expert system for planning landfill restoration
Authors: Basri H.
Published: May 2018

The application of expert systems technology in the domain of environmental management is particularly appropriate in order to preserve and disseminate efficiently valuable and scarce expertise at reasonable costs. The Landfill Restoration Plan Advisor (LRPA) is an expert system designed for use in the planning of sanitary landfill restoration. This paper describes the LRPA and the methodology and techniques that were employed for its development. A unique feature of this experience was that knowledge was acquired from multiple expertise sources in various forms. Expertise acquired from text analysis of textbooks and manuals was used in developing the core knowledge base for the expert system; while those acquired from text analysis of research publications and interviews with selected domain experts was used in the subsequent refinement and expansion of the basic prototype. The building process for the LRPA prototype adopted a modular approach using the incremental rapid prototyping methodology.
Determination of agrochemical combinations in spiked soil samples
Authors: Babic Sandra , Kastelan-Macan Marija , Petrovic Mira
Published: May 2018

Quantitative determination of combinations of the agrochemicals: atrazine, propham, chlorpropham, diflubenzuron, α-cypermethrin and tetramethrin from spiked soil is reported. Method involves ultrasonic extraction of agrochemicals with acetone, separation of samples by means of reverse-phase thin-layer chromatography and quantification by slit-scanning densitometry. Computer-assisted optimisation was used to select the optimum mobile phase composition. Apparent recoveries of agrochemicals from spiked soil were: 90.3±8.5 for chlorpropham, 79.3±10.3 for propham, 102±2.4 for atrazine, 100.6±5.4 for α-cypermethrin, 103.0±4.1 for tetramethrin and 98.3±4.9 for diflubenzuron.
Use of on-line data to evaluate the activity in the biological stage at a wastewater treatment plant
Authors: Björlenius B. , Reinius L.-G.
Published: May 2018

Today many WWTPs are equipped with different on-line instruments for automatic and manual control of the process. The use of computerised systems for data acquisition gives us new possibilities to evaluate collected data. This study shows the possibilities and potentials in using standard equipment, simple calculations and the biological stage as a measuring cell for activity determinations.

Evaluation of data from Henriksdal and Bromma WWTP give some examples from the biological stage where activity can be calculated on-line. The calculation of Oxygen Uptake Rates, OUR, can be used in several ways: a) Estimation of the overall activity in the aerated part of biological stage. b) Calculations of the load of oxygen consuming substanses on the aerated basin. c) Calculation of nitrification rate. d) Estimation of necessary aerated volume. e) Rapid detection of inhibition of the nitrification (and other oxygen consuming reactions). One advantage with these calculations is the fast response to changes.
Upgrading an anaerobic/aerobic wastewater treatment plant
Authors: Austermann-Haun U. , Lange R. , Seyfried C.-F. , Rosenwinkel K.-H.
Published: May 2018

The given example of an anaerobic/aerobic wastewater treatment plant ((WWTP) for a big German brewery shows that it is possible to reduce the discharged values to a very low level, much lower than the minimum requirements of Appendix 11 of the German General Wastewater Administration Rule, which applies to breweries. This means that the present state of technology has been updated.

Tests on a semi-technical scale were carried out and found to be necessary to find the most suitable design for the wastewater treatment plant. Running the tests in the brewery, it became obvious that disinfectants had to be substituted until a stable COD elimination was achieved. Full-scale tests in the plant would not have been feasible. Numerous modifications were carried out in the brewery to reduce the amount of cleaning and disinfectant agents as well as the amount of AOX, EDTA, NTA and aluminium used.

The following article presents the findings of the investigations about the ammonification of organic nitrogen, bulking sludge and substrates for denitrification. Furthermore it demonstrates the low operating costs of anaerobic pre-treatment, even in combination with an aerobic stage and filtration unit.
COD modelling in sewer networks
Authors: Zug M. , Girard R. , Phan L. , Rossi L. , Bellefleur D.
Published: May 2018

In the context of the threat to the environment represented by the pollution of storm water, modelling is one way to study, characterize, understand and finally anticipate this pollution. This paper presents the modelling of the pollutants which are strongly attached to the suspended solids trough a potency factor governing the relation between these pollutants and TSS, developed for the COD. The constant potency factor throughout a subevent used in Flupol and Hydroworks DM is verified through an enlargement of the pollution database and a new variable formulation is presented. Simultaneous measurements of rainfall, hydraulic, TSS and COD concentration on three catchments which presented different characteristics and not used in the calibration phase allowed a large range of validation. This model provides a satisfying fitting of the real COD pollutographs and this, considering the general shape, overall and peak values, the variation of the potency factor (COD/TSS) through the rainfall and the simulation at the beginning of the rainfall.
Design criteria of underflow baffles for control of floatables
Authors: Cigana J. , Lefebvre G. , Marche C. , Couture M.
Published: May 2018

Underflow baffles have gained in popularity over the last few year as a viable means to intercept floatables in Combined Sewer Overflows (CSOs). This has happened although the efficiency of underflow baffles has never been clearly proven. Furthermore, there are no guidelines helping planners in the correct and efficient design of underflow baffles. This article proposes design criteria deduced from pilot scale essays performed in a 17 meters basin at various flowrates. These new informations can be used in two different ways. First, these criteria can be used to correctly design a new overflow chamber. Secondly, these criteria can be used to evaluate the efficiency of existing overflow chambers. Preliminary analysis of existing chambers show that interception efficiency of floatables can be very low.
pH and Mg/Ca control for biological treatment of an offensive flavour (2-MIB)
Authors: Sumitomo H.
Published: May 2018

From a series of experimental observations, it was found that removal rates of the offensive flavor 2-methyl-isoborneol(2-MIB) and ammonia by a biological treatment for water supply were rather unstable and that the removal rates of them often became reverse such as low removal in 2-MIB and high removal of ammonia. One reason for the reverse phenomenon was found that the affinities of sludge around bacteria with 2-MIB and ammonia often became reversed. The affinities of sludge with 2-MIB and ammonia were found to be changeable depending upon pH along with magnesium (Mg) and calcium (Ca) concentrations in sludge. From these findings, control of pH and magnesium calcium ratio (Mg/Ca) of raw water was recommended for simultaneous and stable removal of 2-MIB and ammonia. From plant scale experiments equipped with automatic pH controller, the effects of pH and Mg/Ca control for biological treatment of 2-MIB and ammonia were observed in a biological activated filtration. Here, a biological activated carbon filtration means a longer filtration than 40 to 50 days from the beginning. The obtained results were almost as expected, showing high removal rates of both 2-MIB and ammonia.
Cyanide and metal pollution by urban snowmelt: impact of deicing compounds
Authors: Novotny Vladimir , Muehring Deron , Zitomer Daniel H. , Smith Daniel W. , Facey Roderick
Published: May 2018

Highway and road deicing operations provide traffic safety during winter driving conditions in snowbelt areas. Using large quantities of deicing chemicals causes water quality problems that need to be addressed and remediated. Two specific problems are discussed, i.e., presence of cyanides in deicing salt and decreased partitioning of metals in snowmelt resulting from high salt concentrations. Complex ferrocyanide compounds are added to salt to prevent caking. By photodecomposition, these cyanides can be broken down to free toxic cyanide compounds. For toxic metals, salt decreases partitioning between adsorbed (precipitated) and dissolved metals, resulting in an increase in dissolved metals in salt laden snowmelt and consequently increasing toxicity.
Treatment of biosolids flushed from sewer systems: characterization of biosolids and the sand extracted and the handling of washing water
Authors: Montréjaud-Vignoles M. , Poujol T. , Vignoles C.
Published: May 2018

A research program on the characteristics of biosolids flushed from sewer systems in Toulouse (southwest France) and on the quality of sand extracted from these biosolids by hydrocycloning was carried out using samples from different sites. The treatment of washing water through air flotation was also studied. These initial results show the difficulty in establishing a strict typology for each family of flushed biosolids. On the other hand, the measurements done after hydrocycloning the biosolids clearly show that it is possible to imagine high performance treatment centers which would be able to provide a homogeneously treated product only slightly polluted, starting from very variable waste. Under certain operating conditions. The flotation of washing water thus perfectly completes the treatment of biosolids, and allows one to obtain the weakest possible volume of residue.
Wastewater treatment and risk assessment in ocean outfall evaluations
Authors: Garber William F.
Published: May 2018

Past evaluations of the success of wastewater treatment and submarine outfall placement and operation have considered only a limited number of parameters affecting the marine and onshore environments. Important questions regarding the best allocation of available funds have not been adequately addressed. The relative contamination of the sea from airborne and landwash contaminants has not been considered. Neither has the increased air pollution deriving from the energy required for advanced treatment. Similarly, regular epidemiological studies to evaluate actual changes in morbidity arising from drastic changes in treatment and disposal have not been made prior to very large committments of funds. Most importantly, little attention has been given to the relative ranking of all environmental risks within a catchment area. The net result is that, when all factors are considered, the very large expenditures and increased energy use for sanitary wastewater treatment and outfall disposal will have a net negative effect on the physical and societal environment. The City of Los Angeles and the Los Angeles Metropolitan area can be used to illustrate this probability.
Municipal waste discharge policies in Washington State and recent discharge issues between the State and British Columbia
Authors: Loehr Lincoln
Published: May 2018

Federal and state laws mandated secondary sewage treatment for all municipal dischargers in the state of Washington regardless of need. Evidence supported the suitability of lesser amounts of treatment and the use of industrial source controls as protective of water quality, but could not be considered. The full implementation to secondary treatment is now complete.

In the 1990's, the media, environmental activists and various local, state and federal politicians from Washington State became upset with Victoria, British Columbia when they realized that most of the sewage from the greater Victoria area was only screened prior to discharge to the Strait of Juan de Fuca. The perception was tainted by a lack of understanding of the benefits and power of rapid dilution, and also the mistaken impression that the excessive treatment requirements in Washington were actually needed for water quality reasons.

A British Columbia/Washington State Marine Science Panel was established by the political leaders of the province and state to examine issues of the shared marine waters. The Panel concluded Victoria's discharges were not a problem. The media in Washington State did not report this, and the director of the state's environmental agency expressed disappointment rather than relief with the finding.
Financing public water management: dealing with economic costs of water use
Authors: van Hijum Y. J.
Published: May 2018

Today, many scientists and policy makers underline the importance of internalizing all social and economic costs in charges and prices for water use. Ideally, all service and environmental costs should be recovered in conformity with “polluter pays” and “user pays” principles, using the water system (or river basin) approach to detect these costs. Attempts in The Netherlands to implement these principles however, show that it is not always easy to deduct just charges and prices from hydrological cause-effect relations. Such charges and prices do not always provide adequate signals to users and polluters. The institutional framework and the social, economic and political context determine where and how these financing principles can be implemented. The focus should therefore shift from “blind” charges on pollution and abstraction to (self-)imposed efforts made to measure.
Evaluation model of policy scenarios for basin-wide water resources and quality management in the tone river, Japan
Authors: Aramaki T. , Matsuo T.
Published: May 2018

The objective of this study is to evaluate the conceptual scenarios of various water resources and quality management on the same level of policy decisions for optimizing river basin management. First, the water and pollutants balance model in the upper reaches of the Tone River is proposed. This model has the following characteristics: (1) Water quantity and quality at various target points of the rivers are estimated simultaneously, with a statistical evaluation for the uncertainty of hydrological events; (2) The management scenarios include selection of water savings in domestic use, reservoir construction, the expansion of sewerage coverage and so on. Several interesting results supporting policy making are obtained as follows: (1) Fifteen percent reduction in domestic use is sufficient as a substitute for new reservoir; (2) the expansion of sewage coverage in the upper reaches has large effects on reduction of BOD and COD, but the nutrient removal process should be introduced in sewage treatment plants for reduction of TN and TP.
Analysis of rainfall time series with regard to temporal disaggregation for the use in urban hydrology
Authors: Burckhardt-Gammeter S. , Fankhauser R.
Published: May 2018

The temporal resolution of rain data recorded by national weather services is often lower (10-min resolution) than the data needed for rainfall-runoff simulations (1-5 min resolution). However, the time series are sufficiently long for statistical analysis. The goal of the project presented here is to develop a procedure that disaggregates the 10-min rainfall data of the Swiss Meteorological Institute (SMI) to I-min time resolution. The aim is to implement the procedure in a computer program which can be used by practitioners for generating high resolution rainfall time series at a specific location. In a first step the 1-min data and the 10-min data of two rainfall time series in Switzerland (Heiden, Lucerne) were compared to find characteristic patterns and correlations. The position of 1-min peak within the 10-min interval, the ratio of 1-min peak to 10-min intensity as well as the distribution of the 1-min values within the 10-min interval were investigated. The analysis showed that the positions of the 1-min peaks within a 10-min interval were not uniformly distributed. The distribution depended on the temporal trend of the 10-min values. The ratio of 1-min peak to 10-min intensity seemed to tend towards a constant ratio for high intensities. The results for the two series (Heiden and Lucerne) were not significantly different. These first findings are encouraging with regard to developing a disaggregation to 1-min values which satisfy the accuracy needed in urban hydrology.