bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of liquid phase on VOC removal in trickle-bed biofilters
Authors: Zhu Xueqing , Alonso Cristina , Suidan Makram T. , Cao Hongwen , Kim Byung J. , Kim Byung R.
Published: May 2018

The objective of this work was to analyze the effect of water content on the removal of volatile organic compounds (VOCs) in gas phase trickle-bed biofilters. Previous studies revealed that excessive accumulation of biomass in the reactor had a negative effect on contaminant removal efficiency. To solve this problem, periodic backwash was used to remove excess biomass and maintain an effective operation. Results showed that the ether removal efficiency dropped immediately after backwashing and gradually improved to reach the optimal value within about 24 hours. The initial drop in performance can be attributed to biological effects, such as loss of active biomass and the necessity for an adaptation period for the microbial culture. However, mass transfer limitations due to the water retained in the reactor may also be important. To investigate the effect of water content on the biofilter performance, an experiment evaluated the effect of draining after backwashing was conducted. Biofilters were allowed to drain for different periods of time before restarting the reactors. A longer lapse time in draining before the restart resulted in better ether removal efficiency. The improvement of biofilter performance after backwashing was explained with a combination of biological and physical effects. A mathematical model was then used to simulate the performance of the biofilter under these conditions and to support the conclusions obtained. The mathematical model considered a three-phase system (biofilm, water, and gas phase), dunamic processes, non-uniform bacterial population, and one limiting substrate.
Sewage odour measurements using a sensory panel and an electronic nose
Authors: Stuetz R. M. , Engin G. , Fenner R. A.
Published: May 2018

Odour bags from 10 sewage treatment works were used to assess the application of using an electronic nose to monitor sewage related odours. Canonical correlation (a data reduction technique) was used to compare the multivariate data generated by the NOSE (Neotronics Olfactory Sensing Equipment) with independent sensory panel analysis. Comparisons between the NOSE output and threshold odour numbers (TON) showed that no universal relationship exists between the NOSE and TON for sewage odours from a range of locations within different works. However, when similar groups of data from the same works (ie. biofilters) were compared, a linear relationship can be obtained between the NOSE output and corresponding TON values. Furthermore, this relationship could be extended to similar odours samples from different works, when only low TON values (ie. less than 4000 ou/m3) were analysed.
Fate of dissolved odorous compounds in sewage treatment plants
Authors: Nurul Islam A. K. M. , Hanaki Keisuke , Matsuo Tomonori
Published: May 2018

The concentration of selected malodorous compounds dissolved in water in different unit processes of actual treatment plant, and in different location of small scale treatment plants (Jokasos) were identified in order to provide sufficient information to undertake proper action to solve the problems of malodor compounds in water environment and in wastewater reuse. Analytic methods to measure as low as mg/l level of 16 odorous compounds were developed. In total, four sewerage treatment plants, three sludge treatment plants and six Jokasos were surveyed. Treatment plants were chosen in a way so that most types of unit processes could be covered. Being exposed to anaerobic condition is the primary reason of production of odorous compounds. As far as the secondary treatment is operated properly, odorous compounds concentration in the effluent can be maintained below odor threshold concentration. Odorous compounds were produced during sludge treatment process while the sludge is sedimented, thickened and dewatered, or anaerobically digested. A new way to express the odor concentration is proposed to obtain quick and comprehensive visualization of odor intensity.
Groundwater denitrification with alternative carbon sources
Authors: Mohseni-Bandpi A. , Elliott D. J.
Published: May 2018

A pilot scale rotating biological contactor (RBC) was used to investigate the removal of nitrate-nitrogen from groundwater using three different carbon sources, i.e., methanol, ethanol and acetic acid. Optimum carbon sources to influent nitrate-nitrogen ratio were established by varying the influent concentration of carbon sources. The optimum ratio of methanol, ethanol and acetic acid to nitrate-nitrogen ratios were found to be 2.9, 2.35 and 4.3 respectively. The nitrate-nitrogen removal efficiency averaged 93, 91 and 98 for methanol, ethanol and acetic acid respectively at a loading rate of 76 mg/m2.h. The results of this study show that the acetic acid is the most efficient carbon source for removal of nitrate-nitrogen. Effluent nitrite-nitrogen concentration was minimum for acetic acid as compared with ethanol and methanol. The effluent contained minimum suspended solids and turbidity for methanol as a carbon source. The results of this study indicate that biological nitrate removal using a RBC is a reliable and stable system under all the three carbon sources. The denitrified water in all cases requires some post treatment to oxidise the residual carbon source and remove biomass before distribution.
Field evaluation of a photocatalytic oxidation technology
Authors: Topudurti Kirankumar , Wojciechowski Mary , Anagnostopoulos Sandy , Eilers Richard
Published: May 2018

A commercial-scale photocatalytic oxidation system developed by Matrix Photocatalytic Inc. (Matrix) was evaluated to generate performance and cost data for the treatment of groundwater contaminated with volatile organic compounds (VOCs). High percent removals (up to 99.9%) were observed for aromatic and unsaturated VOCs. However, saturated VOC removals were insignificant. Oxidant addition to the contaminated groundwater significantly improved the treatment system performance. The Matrix system performance was reproducible under identical operating conditions. Treatment by the Matrix system did not reduce the groundwater toxicity for water fleas and fathead minnows at the 95% confidence level. Toxicity reduction achieved through VOC removal appears to have been negated by the formation of toxic byproducts including aldehydes and haloacetic acids. Estimated treatment costs are about $7.60 per 1,000 litres of groundwater.
Characterization and monitoring of persistent toxic organics in the aquatic environment
Authors: Schröder H. Fr.
Published: May 2018

The effluent of a biological waste water treatment plant containing mainly non-eliminable polar compounds was treated using different types of elimination techniques. Precipitation/flocculation with ferric salts, adsorption onto lignite coke or powdered activated carbon (PAC) were used besides oxidative treatment steps like ozone (O3) with or without ultraviolet (UV) radiation and hydrogen peroxide (H2O2) in combination with UV for elimination or degradation. Sum parameter analysis and substance-specific flow injection mass spectrometry (FIA/MS) were used for monitoring the elimination efficiency. Tandem mass spectrometry (FIA/MS/MS) was applied for identification. No elimination could be observed under all treatment steps applied, but degradation by oxidative processes led to improved biodegradability. The results of microtoxicity and daphnia magna toxicity testing after O3/UV und H2O2/UV treatment differed widely.
Socio economic influences on the restoration and maintenance of the water environment
Authors: Matthews Peter
Published: May 2018

Protection of the water environment has become a modern socio economic issue in which the sociological pressures for a healthy water environment must be balanced with affordability. Reconciliation of these aspects requires clear political thinking and rigorous methodologies. It also requires a shift in mind-set which considers members of the public as customers.

Water utilities are the major users of the water environment and potentially its greatest threat – so good delivery of water services is very important. The presentation addresses the topic through the experience of Anglian Water, a privatised water utility serving Eastern England.
Surfactant enhanced remediation of cadmium contaminated soils
Authors: Doong Ruey-an , Wu Ya-Wen , Lei Wen-gang
Published: May 2018

An investigation involving the addition of surfactant to remediate cadmium-contaminated soils was performed to determine the optimal surfactant enhanced remediation system. Anionic (sodium dodecyl sulfate, SDS), nonionic (Triton X-100, TX100) and cationic (cetyltrimethylammonium bromide, CTAB) surfactants were used to elucidate the extraction efficiency of surfactant. EDTA and diphenylthiocarbazone (DPC) were also added to enhance the extraction efficiencies of surfactants. Moreover, the pH effect was examined to determine the optimal surfactant systems. The addition of anionic and nonionic surfactants can enhance the desorption rates of cadmium, lead and zinc, whereas the addition of cationic surfactant decreased the desorption efficiency of heavy metals. The desorption efficiency was found to increase linearly with the increasing surfactant concentration below critical micelle concentration (CMC) and remained relatively constant above the CMC. Moreover, the addition of EDTA can significantly enhance the desorption efficiency of heavy metals. Cationic surfactant was shown to be a more effective surfactant than nonionic and anionic surfactants in extracting heavy metals under acidic environment. The desorption efficiency of heavy metal in the surfactant/EDTA mixture system was in the order of Cd > Pb > Zn. However, the addition of DPC lowered the heavy metal removals by 2 to 4 times. Also, increasing pH value can decrease the extraction capabilities of nonionic and anionic surfactants. The results of this study demonstrate that surfactant in combination with complexing agents can be effectively used as chemical amendments to flush cadmium-contaminated soil by proper selection of type and concentration of surfactant and complexing agent at different pH values.
Batch and column tests for the development of an immobilization technology for toxic heavy metals in contaminated soils of closed mines
Authors: Jang A. , Choi Y. S. , Kim In S.
Published: May 2018

Laboratory tests of various chemical treatments for the immobilization of copper, nickel, and lead in soils typically found at mine facilities were evaluated. A series of batch, adsorption tests, and lab-scale continuous column tests were conducted to optimize the design parameters for the full-scale immobilization processes. The laboratory test program consisted of batch and column experiments to measure the leachability and subsequent immobilization of the single heavy metal, Cu2+, Pb2+, and Ni2+ in an artificial soil which was composed of bentonite and quartz fine sand. Batch equilibrium methods were used to test the ability of a large number of chemical additives to react with heavy metals in contaminated soil. The two best treatment chemicals (CaO and Na2S) for each soil-metal combination were selected for more detailed columns studies. The column tests were carried out in the acidic pH range. According to the results of the column leaching test, it was found that the degree of heavy metal leaching is highly dependent on pH. An adsorption test was performed under acidic conditions (pH 4) to evaluate bentonite as an additive to treat acid mine drainage (AMD).
Improvement priorities for sewage treatment in Latvian small and medium sized towns
Authors: Martin J. C. , Hoggart C. , Matisa A.
Published: May 2018

This paper describes the development of a strategy to identify the priorities for investment in sewage treatment in the rural areas in Latvia. The strategy is developed from the baseline conditions ascertained for the present quality of the many receiving waters (rivers, lakes, ground water and the Baltic Sea) and from the condition of the 800 Plus sewerage systems which serve all of the small and medium sized towns in the country. Technical solutions are developed consistent with Latvian policy goals and the priorities established for improvement to the environment and public health. An investment strategy has been prepared to optimise the use of the available funds, to achieve the best value for money. It has been agreed in consultation with interested parties at national, regional and local levels, to produce a plan with wide acceptance. The strategy is known in Latvia as ‘800 Plus’.
Cost efficiency of subsurface remediation using soil vapor extraction and groundwater extraction
Authors: Hirata T. , Egusa N. , Nakasugi O. , Ishizaka S. , Murakami M.
Published: May 2018

The groundwater pollution due to volatile organochlorines like trichloroethylene and tetrachloroethylene has been a great environmental issue in Japan. The nation wide survey revealed on the basis of up to fifty-nine thousand samples collected until 1995 that 1.5% for trichloroethylene and 2.3% for tetrachloroethylene cannot meet the drinking water standard. In order to repair subsurface pollution and to establish the integrated procedure for cost-benefit remediation measure, physical remediation technologies of soil vapor extraction and groundwater extraction were applied to a study site contaminated with trichloroethylene. The results showed that the trichloroethylene amounts of 472 kg by soil vapor extraction and 1764 kg by groundwater extraction were removed during three-year operation. In addition experience with both technologies has demonstrated that the soil vapor extraction has been successful in removing 1 kg hr−1 of trichloroethylene at the initial stage of remediation, which shows one order as high as the groundwater extraction. However, the removal rate due to soil vapor extraction declines much earlier than groundwater extraction, and consequently the removal rates of both technologies develop inversely with the progress of remediation. Such remediation behavior of technologies raised the relative cost for soil vapor extraction 15 times as high as groundwater extraction.
Whole effluent and single substances approach: a tool for hazardous wastewater management
Authors: Gotvajn Andreja Žgajnar , Zagorc-Koncan Jana
Published: May 2018

Evaluation of toxicity and biodegradability or persistencey of different chemical substances and wastewaters is essential for their hazardous impact and risk assessment. Many various types of toxicity and biodegradation assessment tests are nowadays available for evaluation of the effects of pure substances and with proper combination of the tests, the prediction of the effect on the aquatic recipient is possible. On the other hand, there is a lack of agreed test procedures for estimating biodegradability of complex wastewaters. A methodology for wastewater characterisation employing single substance and whole effluent approach using stabilisation study is presented. The aim of the study was to establish the relationship between toxicity and biodegradability of phenol-formaldehyde industrial wastewater and its main constituents to evaluate presented methodology for hazardous wastewater management.
Dynamic simulation for upgrading of wastewater treatment plants—an assessment of treatment plant performance with regard to the EC-directive concerning urban wastewater treatment
Authors: Sintic A. , Rolfs T. , Freund M. , Dorgeloh E.
Published: May 2018

This paper shows how the dynamic simulation of municipal wastewater treatment plants can be used for assessing the performance of a plant under different legal requirements. In this study, the situation is described, when it was uncertain, how the requirements of the German law (ARA-V 1991) would be adapted to the requirements given by the EC-directive concerning urban wastewater treatment (EC directive, 1991). The requirements of these two are compared to each other. A simulation study is described, in which the future results of a plant to be extended are calculated for the period of one year. It is shown that, concerning the effluent concentrations of ammonia and total nitrogen, this plant will be able to meet both laws.
Evaluating ozone dose for AOC removal in two-step GAC filters
Authors: Vahala R. , Ala-Peijari T. , Rintala J. , Laukkanen R.
Published: May 2018

Upgrading an existing post-ozonation plant with two-step granular activated carbon (GAC) filtration for assimilable organic carbon (AOC) removal was studied. The effects of ozone dose on AOC formation and its removal in the subsequent two-step GAC filtration was studied using chemically pretreated 2 to 14° C humic lake water. Two parallel pilot-plant trains with different ozone doses (0 to 1.2 mgO3/mgTOC) and a short-term ozonation study were performed. The optimum ozone dose for maximum AOC formation was 0.4–0.5 mgO3/mgTOC. The AOC-P17 of ozonated water was three-fold higher and AOC-NOX over ten-fold higher than in non-ozonated water, while the following biofiltration (first step) removed 51% and 72% of AOC-P17 and AOC-NOX, respectively. The adsorber (second step) contributed to less than 10% of the overall AOC reduction. It appeared that biofiltration is a feasible method in upgrading water treatment plants for AOC removal even when treating cold humic waters, while the subsequent adsorber seems to have less significance for AOC removal.
Interaction between the treatment plant and the sewer system in Halmstad: integrated upgrading based on real time control
Authors: Hernebring C. , Ohlsson L. , Andreasson M. , Gustafsson L.-G.
Published: May 2018

In Halmstad, Sweden great efforts have been made during the 1990's to improve the functionality and to reduce the environmental impact of the sewer system and the wastewater treatment plant. The investment and rehabilitation program includes to a great extent an effective use of existing resources. The wastewater treatment plant is reconstructed to meet increased nutrient removal demands. A five year rehabilitation plan for the sewer system is under completion, where the measures mainly are motivated by the aim to reduce the combined sewer overflow volumes and to minimize the risk of local flooding. It was soon realized that an integrated use of storage volumes at the wastewater treatment plant and within the sewer system could improve the general conditions for the treatment at the plant. To implement this strategy a real time control system was introduced by installing controllable weirs and flow control devices in the main sewer. The article describes the background of the sewerage master plan, how the upgrading work has been carried out by means of simulations and measurement, gives examples of some expected potential benefits, and outlines plans for the future.
The sharon process: an innovative method for nitrogen removal from ammonium-rich waste water
Authors: Hellinga C. , Schellen A. A. J. C. , Mulder J. W. , van Loosdrecht M. C. M. , Heijnen J. J.
Published: May 2018

A new biological process for ammonia removal from flows containing hundreds to thousands milligrams NH+4 per litre has been developed at the Delft University of Technology. The SHARON process operates at a high temperature (30–40 °C) and pH (7–8). The process is performed without sludge retention. This enables the prevention of nitrite oxidation, leading to lower operational costs. Denitrification is used to control the pH. A full scale plant was designed (1500 m3) based on kinetic and stoichiometric parameters determined at 1.5 1. scale and model predictions. Total costs are estimated at about $1.7 per kg removed NH4+-N. The first full scale SHARON plant will be operational at the Dokhaven waste water treatment plant in Rotterdam in the beginning of 1998. This contribution focuses on the principles of the process and evaluates conditions for which application seems feasible.
Increasing the capacity of an extended nutrient removal plant by using different techniques
Authors: Andersson B. , Aspegren H. , Nyberg U. , la Cour Jansen J. , Ødegaard H.
Published: May 2018

A comprehensive investigation which included full scale tests was initiated towards the late 1980:s with the primary aim to find an appropriate technology for the Klagshamn wastewater treatment plant in Malmö, Sweden. The finally selected strategy enabled that a concentration of less than 8 mg N/l could be reached in the secondary effluent without having to extend either the primary or secondary treatment step at the actual load on the plant. In order to comply with a future stringent phosphorus standard however, a tertiary filtration plant has to be built. In future, it has to be anticipated that the load on the plant may be doubled due to the fact that a bridge between Malmö and Copenhagen is being built. As a consequence, it was important to continue the upgrading work by estimating the ultimate plant capacity and to look for measures to increase the capacity if necessary. By optimising the plant operation, it seems possible to reach an effluent nitrogen concentration of less than 12 mg/l at a load corresponding to the future design load. The suggested approach implies that the plant has to be operated on the margin and as a consequence the possibility to include a denitrification step as part of the filtration plant was also investigated. As a result, it was decided to build a separate denitrification step at the same time as the filtration plant was built.
Water quality improvement in a small stormwater detention pond
Authors: Pettersson Thomas J. R.
Published: May 2018

The aim of this study was to investigate a small open detention pond predominantly receiving stormwater drainage from a highway. The results showed a difference in pollutant removal characteristics. Particle-associated pollutants were effectively removed during storm events as indicated by EMC (Event Mean Concentrations) while dissolved pollutants were not effectively removed. Outflow pollutant loads followed linear profiles when seven consecutive storm events were represented as cumulative graphs. PEMC's (Partial EMC's) during a storm event showed an association between the specific surface area of small particles and lead content. A detention pond should be designed according to capacity to detain the complete storm volume, thus avoiding short-circuiting of the pond by pollutants.
The effects of untreated municipal sewage discharge to the marine environment off Victoria, British Columbia, Canada
Authors: Taylor L. A. , Chapman P. M. , Miller R. A. , Pym R. V.
Published: May 2018

The Victoria area (British Columbia, Canada) discharges screened wastewater through two long deep outfalls (Macaulay and Clover Point) into an oceanic environment characterized by strong turbulent tidal flows. Monitoring of the receiving waters has indicated that conventional water quality parameters have not been affected by the discharges. Fecal coliform levels above the outfalls are periodically elevated but remain well below the swimming standard. Shoreline studies of fecal coliform levels have shown that the deep outfalls have not measurably affected water quality at beaches.

Recently, monitoring efforts have concentrated on effects to the seafloor environment. At Macaulay Point, sediment chemical levels of concern were confined to within 100 to 400 m of the outfall. Similarly, sediment toxicity was detected at stations up to 400 m from the diffusers. This toxicity was limited to effects on growth and development. Survival was not affected. The benthic infaunal community exhibited a typical response to organic enrichment. Within 100 m of the outfall abundance was increased and richness depressed. At Clover Point sediment chemical levels of concern were confined to within 100 to 200 m of the outfall. Tissue chemistry of resident mussels showed no consistent pattern with distance from the outfall. Some tissue chemicals increased with distance from the diffuser while others decreased. Overall the impact of the outfalls on the seafloor was found to be minimal and restricted in extent.
Dilution in a dense bottom jet in cross currents
Authors: Petersen Ole , Larsen Torben
Published: May 2018

A 3-dimensional numerical model describing the dilution in the near field around dense vertical jets in a cross flow is formulated and validated against laboratory experiments. The validation shows that the model reproduces the flow pattern well, though the dilution is underestimated by 20%. The model is applied to a case study where the dilution from two vertical jets at an angle in shallow water is described. It is demonstrated that a 20% increase in dilution is possible. It is concluded that the model may become a valuable tool in diffusor design.
Wastewater diffusion in the estoril coast: theoretical calculations and field studies
Authors: Matos J. , Monteiro A. , Costa P. , Neves R. , Bettencourt A. , Frazao A. , Santos C.
Published: May 2018

The Costa do Estoril sewerage system is located on the west side of the Lisbon region, off the mouth of the Tagus river. This system was planned in order to free the pleasant beaches of the region from any wastewater discharge and is prepared to serve, at the final phase, more than one million inhabitants.

In the Costa do Estoril a long sea outfall with two diffusers is used for final wastewater disposal. This system has been operating since 1994. In this paper nearfield dilution corresponding to present working conditions are presented. For simulation of nearfield dilution CORMIX 1 and CORMIX 2 (Cornel Mixing Zone Expert System) were applied. The basic data for modelling was selected according to field studies obtained under an ongoing environmental monitoring program.
Facilities development and planning model - a management tool for the strategic planning process and application thereof
Authors: Wilken J. W. , Nel N. J. , Hugo W.
Published: May 2018

The comprehensive content of the planning process for wastewater conveyance and treatment facilities, and the optimization thereof, resulted in the development of the Facilities Development and Planning Model (FDP). The FDP model was developed for the operators of wastewater care facilities in order to obtain an efficient and dynamic means of assessing the regional inputs, evaluating the existing system and situation, and for considering various generic scenarios.

The FDP model can be adapted to be utilized for the planning of facilities for other bulk services infrastructure.

The paper describes the application of the FDP model in an wastewater treatment environment.
The effects of non-stationarity on the evaluation of critical design storms
Authors: De Michele C. , Montanari A. , Rosso R.
Published: May 2018

The critical storm is generally carried out to design urban drainage systems and other flood management works starting from the available historical information. Its evaluation associated with a fixed return period is usually obtained by fitting the annual maxima of the rainfall depth with an extreme value distribution. This statistical procedure, however, leads to dubious results when the data present a non-stationarity, induced for example, by a long-term variability. To assess the effects of non-stationarity, four daily rainfall series observed in Italy, with at least 90 years of continuous data, are analysed here. For each record and each year of the observation period, critical design storms are estimated fitting the annual maxima collected in the past, so allowing us to assess the progress of the design storm along time. Four different extreme value distributions are used. The results show that an analysis of non-stationarity is required when urban drainage systems and other hydraulic engineering works are designed.
Uncertainties and trends in extreme rainfall series in Tuscany, Italy: effects on urban drainage networks design
Authors: Pagliara S. , Viti C. , Gozzini B. , Meneguzzo F. , Crisci A.
Published: May 2018

Sound basin management at urban or greater scale needs reliable design storm definition. A statistical analysis is carried out on extreme annual rainfall series for durations of 1, 3, 6 and 12 hours occurring at two gauges in Tuscany, Italy. Kendall's test is applied to the extremal series to detect a definite increasing (or decreasing) trend. A special form of an ARIMA model is also fitted to the series to quantify possible linear trends and their respective significance. Results show a clearly increasing trend at shortest duration at both gauges, no trend at longer ones. Time evolution of design storms for all durations and return periods up to 25 years is derived and analysed based on Gumbel distribution. Applications are presented concerning impacts of uncertainties for the design of urban drainage networks.
River Water Quality Modelling: II. Problems of the Art
Authors: Shanahan P. , Henze M. , Koncsos L. , Rauch W. , Reichert P. , Somlyódy L. , Vanrolleghem P.
Published: May 2018

The U.S. EPA QUAL2E model is currently the standard for river water quality modelling. While QUAL2E is adequate for the regulatory situation for which it was developed (the U.S. wasteload allocation process), there is a need for a more comprehensive framework for research and teaching. Moreover, QUAL2E and similar models do not address a number of practical problems such as stormwater flow events, nonpoint source pollution, and transient streamflow. Limitations in model formulation affect the ability to close mass balances, to represent sessile bacteria and other benthic processes, and to achieve robust model calibration. Mass balance problems arise from failure to account for mass in the sediment as well as in the water column and due to the fundamental imprecision of BOD as a state variable.
Education and training of water practitioners in South Africa: needs and programmes
Authors: Schutte C. F.
Published: May 2018

South Africa is facing severe water supply and water quality problems as a result of its limited water resources and other complicating factors. Adequately educated and trained water practitioners are needed to address these problems to ensure economic prosperity and a reasonable standard of living for all South Africans. Training and education needs are analysed in this paper and available programmes and initiatives to deliver the water practitioners needed are discussed. The main areas where training and education is needed include education at community level to educate local water committee members and community support personnel; training of technical staff to operate and maintain water treatment and supply schemes; and education of high-level scientists and engineers to develop new technologies, to improve performance, design and management of processes, plant and projects.
A risk/cost analysis to manage viral contamination of groundwater
Authors: Adelman D. D. , Stansbury J. , Tabidian M. A.
Published: May 2018

Under the proposed groundwater disinfection rule of the 1986 Safe Drinking Water Act, municipal water systems have four options to demonstrate that natural disinfection of viruses occurs between the virus source and the municipal well. One option is to demonstrate that the necessary set-back distance exists between these facilities. The objective of this research was to evaluate the risk that virus concentrations at a municipal well would exceed recommended levels even though the virus source was separated from the well by the set-back distance recommended by the EPA. Groundwater transport modeling was used to evaluate this risk and compute the necessary distance upgradient from each Nebraska municipal well for sufficient virus die-off to occur. The number of wells with computed die-off distances greater than the regulatory set-back distances were divided by the total number of wells. The results of this research show that the potential risk for virus concentrations will exceed recommended virus levels in municipal wells using EPA's set-back distances.
Twenty years development of ICA in a water utility
Authors: Huntington R.
Published: May 2018

Wessex Water Authority was established in 1974 to manage water supplies, sewerage and sewage treatment in its area. The shortcomings of inherited assets demonstrated the need for better monitoring and control of water and waste water facilities. It was recognised that new developments in ICA could make a vital contribution to better management of assets. Accordingly, over ensuing years, a framework for a regional monitoring and control scheme was developed and established. Over the past two decades experiments with new and developed equipment and techniques have given beneficial results but there have been some disappointments. Development of the scheme is described briefly and comments made on identified improvements to on-line and off-line systems. Some disappointments are also discussed. Human aspects also receive attention. Further desirable improvements are presented.
Control of sewer systems and wastewater treatment plants using pollutant concentration profiles
Authors: Bechmann Henrik , Nielsen Marinus K. , Madsen Henrik , Poulsen Niels Kjølstad
Published: May 2018

On-line measurements of pollutants in the wastewater combined with grey-box modelling are used to estimate the amount of deposits in the sewer system. The pollutant mass flow at the wastewater treatment plant is found to consist of a diurnal profile minus the deposited amount of pollutants. The diurnal profile is found to be a second order harmonic function and the pollutants deposited in the sewer are identified using first order ordinary differential equations.
RT-PCR amplification detects inactivated viruses in water and wastewater
Authors: Sobsey M. D. , Battigelli D. A. , Shin G.-A. , Newland S.
Published: May 2018

Nucleic acid (NA) amplification techniques are useful to detect viruses in water and other environmental samples because they are highly sensitive, specific and can detect fastidious enteric viruses that do not grow well or not at all in cell cultures. However, RT-PCR was found to detect inactivated viruses. In terms of risks to public health this constitutes a false positive result, as inactivated viruses are no longer infectious. When poliovirus type 1 and coliphage MS2 were studied for (a) persistence in water and sewage and (b) inactivation in water by free chlorine, chlorine dioxide and UV radiation, RT-PCR assays underestimated virus inactivation. The use of multiple RT-PCR amplification sites, larger RT-PCR genomic targets and immunocapture RT-PCR sometimes reduced, but did not eliminate, the discrepancy between loss of infectivity and loss of RT-PCR titre. Virus presence based on RT-PCR detection must be interpreted with caution when predicting human health risks.
Reduction of FRNA-bacteriophages and faecal indicator bacteria by dune infiltration and estimation of sticking efficiencies
Authors: Schijven J. F. , Hoogenboezem W. , Nobel P. J. , Medema G. J. , Stakelbeek A.
Published: May 2018

A field study was performed to investigate reduction by dune infiltration and to estimate sticking efficiencies of F-specific RNA bacteriophages, total and thermotolerant coliforms, faecal streptococci and spores of sulphite-reducing clostridia. Reduction was considered as a β-binomially distributed process and a Monte Carlo simulation was applied for estimating sticking efficiencies. Reduction of F-specific RNA bacteriophages within the first 2m was 3.8 log10 and the sticking efficiency was about 0.002. The faecal indicator bacteria were removed only 0.9 log10 within 2m and sticking efficiency was 0.007. Concentrations of spores of sulphite reducing clostridia were reduced 1.9 log10 and their sticking efficiency was about 0.009.
Multivariable modeling and control of an activated sludge process
Authors: Lindberg Carl-Fredrik
Published: May 2018

This paper contains two contributions. First it is shown, in a simulation study using the IAWQ model, that a linear multivariable time-invariant state-space model can be used to predict the ammonium and nitrate concentration in the last aerated zone in a pre-denitrifying activated sludge process. Secondly, using the estimated linear model, a multivariable linear quadratic (LQ) controller is designed and used to control the ammonium and nitrate concentration.
The influence of environmental factors on microbiological indicators of coastal water pollution
Authors: Serrano E. , Moreno B. , Solaun M. , Aurrekoetxea J. J. , Ibarluzea J.
Published: May 2018

The relationships between bacteriological and viral indicators of sewage pollution (TC, FC, E coli, FS, Salmonella, somatic coliphages and F-RNA phages) and environmental variables in coastal water and weather were studied at three beaches in San Sebastian, the Basque Country. The microbiological indicators in bathing water presented high counts associated with the following conditions: early morning, overcast skies, low and high tides, groundswell, intense turbidity and the presence of flotsam (P = <0.05). Coliphage density was significantly related (P = <0.05) to cloud cover, groundswell and flotsam. Correlations between microbiological indicators proved high (0.62 ≤ r ≤ 0.90, P = <0.001). The percentage of Salmonella presented significant (<0.05), albeit low (r < 0.4), correlations with all microbiological parameters. Somatic coliphages also revealed highly significant (0.32 ≤ r ≤ 0.66) correlations (P = <0.001). Those obtained for F-RNA phages, in contrast, were low (r ≤ 0.33). The equations obtained using a multiple regression analysis with a view to predicting microbiological, viral, and Salmonella indicator density demonstrated that environmental variables facilitate the construction of highly significant equations, but that these have low predictive capability (R2 = <0.50).
The use of an on-line respirometer for the screening of toxicity in the antwerp WWTP catchment area
Authors: Geenens D. , Thoeye C.
Published: May 2018

Following the new European and Flemish environmental legislation most of the existing Flemish wastewater treatment plants (WWTP) have to be adapted to achieve nutrient removal. The Antwerp WWTP Deurne-Schijnpoort (230,000 PE) is to be renovated to achieve a 10 mg/l total nitrogen and a 1 mg/l total phosphorous effluent consent. Six months of intensive pilot work at this plant has shown total nitrification inhibition of one- stage activated sludge processes. A mobile on-line respirometer was installed to monitor the activated sludge inhibition at the WWTP. Toxicity resulting in a substantial deterioration of the WWTP effluent was observed. Industrial discharges and main junctions in the sewer system were sampled for specific monitoring. An industrial source of inhibition could be pinpointed. Full-scale operating experiences with the respirometer during the measurements are reported.
Water quality monitoring-technological advantages and potential developments in the use of fibre optic technology
Authors: Grattan K. T. V.
Published: May 2018

In this paper, a review of the primary drivers of the use of optical and fibre optic technology upon water quality monitoring is considered. The technological advances and challenges are discussed and the potential impact of new components, devices and methods illustrated for environmental monitoring into the future, using optical techniques.
An environmental process control laboratory: at the interface between instrumentation and model development
Authors: Beck M. B. , Watts J. B. , Winkler S.
Published: May 2018

Success in the development and application of a model requires, as a rule, high-quality field data. In general, studies in controlling the dynamics of wastewater treatment processes have been poorly served in their access to such data. The Environmental Process Control Laboratory has been developed in order to rectify this limitation. The Laboratory is a mobile facility housing instrumentation for on-line respirometry and sensors for real-time monitoring of sludge blanket level and the concentrations of dissolved oxygen, suspended solids, ammonium-N, nitrite-N, total oxidised nitrogen, total organic carbon and orthophosphate-P concentrations. The Laboratory has been designed for deployment in a variety of contexts, but principally in the study of municipal and industrial wastewater treatment, protection of surface water quality, aquaculture, and groundwater contamination. Its purpose is to support the development of process models and, where appropriate, procedures of decision support and automatic control for these systems. Preliminary results from commissioning trials with the Laboratory at the Athens, Georgia, Water Pollution Control Facility Number 2 are reported. These expose some critical issues of signal pre-processing and the need to re-think a strategy for developing models in order to interpret the very large volumes of data generated by the Laboratory.
Reviewing, assessing and speculating
Authors: Olsson G. , Newell R.
Published: May 2018

A concise assessment is made of the scientific and technical programme of the 7th IAWQ Workshop on Instrumentation, Control and Automation of Water and Wastewater Treatment and Transport Systems. Although progress has been made in certain areas, others are identified as crucial targets for further research and development.
RNA/DNA ratio as an indicator of metabolic activity in resin acid-degrading bacteria
Authors: Muttray A. F. , Mohn W. W.
Published: May 2018

We investigated the relationship between the growth rate and the ratio of RNA to DNA in of four resin acid degrading bacteria isolated from a sequencing batch reactor (SBR). Chemical assays as well as slot blot hybridizations with species-specific oligonucleotide probes were used to quantify the nucleic acids. These slow-growing bacteria have a positive linear correlation between growth rate and RNA/DNA ratio, similar to faster-growing bacteria like E. coli. We propose to use this correlation to measure metabolic activities of selected resin acid degrading bacteria in the complex community of the SBR in situ using species-specific hybridization probes. Preliminary experiments suggest that hybridization probes can be used to detect growth rate-dependent changes in the RNA/DNA ratio.
Innovative biological treatment for sustainable development in the chemical industries
Authors: Eckenfelder W. Wesley , Englande A. J.
Published: May 2018

This paper presents a perspective of wastewater management in the chemical industries as related to sustainable development. The scope of wastewater management must therefore further be expanded to include the concept of ecological integrity of receiving waters. Ecological integrity of receiving waters is compromised by contaminants which are not effectively removed by Best Conventional Technology (BCT). Biological treatment typically offers the most cost-effective conversion and/or stabilization of wastewaters; however, modifications must be employed in the design and operation to provide satisfactory effluent quality. Enhanced treatment techniques for wastewaters containing high organic concentrations, VOCs, elevated TDS levels, toxics and priority pollutants are discussed. The importance of design and operational procedures including pretreatment technologies, two stage vs. single stage activated sludge, selector design and maximum specific oxygen uptake rate determinations are also presented.
Genetic diversity and population dynamics of hyphomicrobium spp. in a sewage treatment plant and its receiving lake
Authors: Fesefeldt Andreas , Holm Niels C. , Gliesche Christian G.
Published: May 2018

Hyphomicrobium spp. were counted and isolated for 12 months in a sewage treatment plant with a combination of simultaneous and intermittent nitrification and denitrification using Most-Probable-Number methods. Genomic DNA of these hyphomicrobia was investigated by Southern or dot blot hybridizations with gene probes specific for genes of dissimilatory nitrate reduction (nitrate reductase, narG; cytochrome c,d-containing nitrite reductase, nirS; Cu-containing nitrite reductase, nirK; nitrous oxide reductase, nosZ), nitrification (ammonia monooxygenase, amoA) and N2-fixation (nitrogenase, nifH). In particular, the Hyphomicrobium DNA/DNA-hybridization group HG 27 constituted one of the dominant denitrifying Hyphomicrobium populations in the activated sludge of this sewage treatment plant. A species-specific gene probe (Hvu-1) for HG 27 was generated from a transposon Tn5-132 insertion mutant defective in methanol oxidation using the inverse polymerase chain reaction. With this probe the abundance of this group in activated sludge of the sewage treatment plant and its receiving lake was determined as a subfraction of the total cultivable hyphomicrobia. Fragments of the mxaF gene encoding for the α-subunit of the methanol dehydrogenase of Hyphomicrobium spp. were amplified by PCR and analysed by denaturing gradient gel electrophoresis (DGGE). The DGGE analysis pattern showed a substantial separation of these fragments according to their nucleic acid sequences.
Detachment of biofilm bacteria due to variations in nutrient supply
Authors: Sawyer Linda K. , Hermanowicz Slawomir W.
Published: May 2018

Growth and detachment rates of an environmental isolate of Aeromonas hydrophila attached to a surface were determined under varying nutrient supply conditions in a complex medium. Growth and detachment of cells were observed in real time using phase contrast microscopy in glass parallel plate flow chambers. Surface shear stress was controlled in all experiments at 3 N m−2. Images were taken every 15 min. Digital image analysis was used to determine specific growth and detachment rates. An observable parameter proportional to the nutrient depletion at the surface due to transfer limitations was used to indicate nutrient limitations. Specific detachment rates increased as the depletion parameter increased, indicating that nutrient limitations cause this bacterium to detach at greater rates.
Biofilm characterization of several wastewater treatment plants with rotating biological contactors in Madrid (Spain)
Authors: Pérez-Uz B. , Franco C. , Martín-Cereceda M. , Arregui L. , Campos I. , Serrano S. , Guinea A. , Fernández-Galiano D.
Published: May 2018

Ciliate communities were studied in the biofilms of three plants with rotating biological contactors (RBCs) over the period of one year. The aims of this study were: (i) to characterize ciliates to species level; (ii) to determine their abundance and spatial variation through the biological system; and (iii) to relate the spatial segregation and richness of ciliate species to plant performance. A number of species ranging from 33 to 67 were identified at the different plants. The overall best represented groups were peritrichs followed by scuticociliates (Las Matas), cyrtophorids (Boadilla) or hypotrichs (Camarma). Comparison of RBCs and activated sludge communities indicated that even though both were mainly constituted by peritrichs, differences in groups and species composition were observed.
A conceptual model describing macromolecule degradation by suspended cultures and biofilms
Authors: Confer David R. , Logan Bruce E.
Published: May 2018

Macromolecular (> 1,000 daltons) compounds such as proteins and polysaccharides can constitute a significant portion of dissolved organic carbon (DOC) in wastewater, but limited information is available on how these compounds are degraded in suspended and fixed-film biological wastewater treatment systems. Bacteria cannot assimilate intact macromolecules but must first hydrolyze them to monomers or small oligomers. Here, we summarize experiments performed in our laboratory which indicate that the enzymes responsible for hydrolysis are primarily those that remain attached to the cell. In biofilm cultures fed macromolecular substrates, for example, no more than 8% of total hydrolytic activity was found to be located in the cell-free bulk solution. These and other experiments support a generalized mechanism for macromolecule degradation by biofilms that features cell-associated hydrolysis, followed by the release of hydrolytic fragments back into bulk solution. The extent of fragment release is larger for proteins (bovine serum albumin) than for carbohydrates (dextrans).