bluuebunny/crossref_metadata_2025 huggingface dataset:
Experiences of wastewater treatment in Chilean forest industry
Authors: Videla S. , Diez C.
Published: May 2018

The present situation of water treatment facilities in the forest industry of Chile is briefly described. Some data of the Chilean pulp mill production and the present level of water pollution are shown. This paper is the result of five years of applied research conducted to study and evaluate liquid effluent treatment from pulp, paper and board mills. We describe laboratory results corresponding to three industrial mills that we have studied. The first case presented in this paper corresponds to a bleached Kraft pulp mill with a fiber line consisting in a MCC digester, a delignification unit and four steps in bleaching. In this mill the effluents are treated in an extended lagoon and the suspended solids are settled in a primary treatment. Lab scale lagoons were installed to developed start up strategies and to determine optimal operational efficiencies. The second case that we present is a paper mill, with primary treatment in an air flotation unit used for separating suspended solids. A technical economical analysis was necessary to burn solid sludge in order to improve energy balance. Finally, the third case we have studied corresponds to a hardboard mill effluent. In this case, high COD, mainly as colloidal solids, characterize this effluent. Laboratory experiences were made using a system of two sequential aerated lagoons.
Ammonia removal by magnesium ammonium phosphate precipitation in industrial wastewaters
Authors: Tünay Olcay , Kabdasli Isik , Orhon Derin , Kolçak Saadettin
Published: May 2018

In this study, the theoretical basis and limitations of magnesium ammonium phosphate (MAP) precipitation are investigated and experimentally tested for leather tanning industry. The MAP precipitation is applied to leather tanning wastewaters for both segregated flows containing high ammonia concentrations and combined flows. Segregated flow treatment on smaller volumes of wastewater provided an ammonia concentration of down to 150 mg l−1 NH3-N. The resulting ammonia concentration of MAP precipitation on combined wastewater is at the level of domestic wastewater which eliminates the need of further nitrogen removal in the biological treatment and provides an effluent quality acceptable for the public sewer.
Pretreatment of wastewater from heavy-oil-pyrolysis-gas-making system
Authors: Fengkai Lin , Yu Wang , Zeng Xu
Published: May 2018

It was found that the process of pressure-hydrolysis failed for the treatment of a wastewater containing cyanide and nickel from heavy-oil-pyrolysis-gas-making system. The analysis of the wastewater showed the existence of Ni2+,CN−,NH3, Ca2+ and HCO3−. Therefore, the coordinate compounds of [Ni(CN)4]2− and [Ni(NH3)n]2+ could be expected. Considering the Ca2+ and potential CO32− transformed from HCO3−, it was not surprising that white precipitate blocked the pipeline within the pressure-hydrolysis process under the condition of high pH. A pretreatment step of calcium removal was suggested. Various factors were investigated and optimal operational conditions were concluded. After calcium was removed, the treatment processes were operated successfully and satisfactory results obtained. The residual concentrations of Ni2+ and CN− could be reduced to meet the discharging standards.
Activated sludge plants in Finland
Authors: Saunamäki R.
Published: May 2018

The performance of Finnish activated sludge plants (primary clarifier, equalization basin, buffer basin, aeration basin, secondary clarifier and sludge handling) was surveyed. Performance was generally found to be excellent. BOD7 removal averaged 94% at paper mills (21mg/l effluent concentration, 0.43 kg/t discharge) and 95% at chemical pulp mills (18 mg/l, 0.83 kg/t). CODCr removal averaged 82% at paper mills (158 mg/l effluent concentration, 3.52 kg/t discharge) and 60% at pulp mills (531 mg/l, 20.7 kg/t). Treated effluent from paper mills contained 0.57 mg/l (13.3 g/t) of total phosphorus and from pulp mills 1.31 mg/l (47.3 g/t). AOX removal was 45-65% and discharge 0.15-0.90 kg/t. Suspended solids removal averaged 91% at paper mills and 76% at pulp mills, the average overflow concentration in primary clarifier being about 150 mg/l at both types of mill. All activated sludge plants are designed according to either the low load or extended aeration principle; high load plants are no longer in use. The average sludge load was 0.15 kg BOD/(kg MLSS d), the sludge age at the extended aeration plants ranging from 20 to 50 d. Low load appearance to be the main reason for the good performance of the plants. Other factors included the introduction of equalization and buffer basins at many plants, and particularly the fact that aeration factors and nutrients were under control. All paper mill activated sludge plants use nitrogen and phosphorus additions, whereas pulp mill plants manage without phosphorus. Optimization of nutrient addition is vital because almost every mill in Finland has a limit for its phosphorus discharge. Total sludge production at the paper mill plants averaged 40.9 t/d, 15% of which (5.9 t/d, 6.0 kg/t) was biosludge. At the pulp mills the figures were 27.2 t/d (11.5 t/d biosludge, 9.5 kg/tp). Belt filter presses are used for dewatering at most plants and dry solids contents are usually 25-35%. New-generation screw presses have been introduced, mainly at new pulp mill activated sludge plants, yielding dry solids contents of 40%. Combined and dewatered sludge is normally burned in bark-fired boilers, although some mills still landfill their sludge.
Microbial treatment of kraft pulp wastewater pretreated with ozone
Authors: Nakamura Y. , Sawada T. , Kobayashi F. , Godliving M.
Published: May 2018

Kraft pulp wastewater was treated with a combination of ozone and activated sludge. The effects of pH on the degradation of lignin and the production of organic acids were examined experimentally in the ozonolysis of wastewater. The strong alkaline condition enhanced not only the degradation of lignin but also the production of organic acids. The dynamic behaviours of microbial growth and substrate consumption were investigated in the biodegradation of organic acids using activated sludge. Maleic acid and oxalic acid in the ozonized wastewater were degraded completely by the activated sludge. The immobilized activated sludge culture using polyurethane foam was effective in degrading organic acids.
Pilot-scale thermophilic anaerobic treatment of wastewaters from seasonal vegetable processing industry
Authors: Rintala J. A. , Lepistö S. S.
Published: May 2018

Thermophilic anaerobic treatment of food industry wastewaters was studied using a 0.65 m3 upflow anaerobic sludge bed (UASB) reactor. The reactor was operated at 55°C and placed on the premises of a factory manufacturing deep-frozen goods from vegetables. The hot (>80-90°C) and concentrated (COD 14-79 g/l) wastewater streams, deriving from steam peeling and blanching of carrot and potato were used.

The UASB reactor was inoculated with a small amount of granular sludge from a full-scale mesophilic UASB reactor. Prior to inoculation, the inoculum was acclimated to 55°C for 2 days. The reactor was fed with a mixture of wastewaters diluted to the desired COD. The reactor was started with loading rates of about 1.2 kgCOD/m3d. After the initial acidification of the process, apparently due to insufficient buffer capacity, the COD removal started to improve and reached 60% within 35 days of inoculation. At the end of the 70 days run, more than 80% COD removal was achieved with loading rates of about 4 kgCOD/m3d. The pilot-study run was limited due to the end of the seasonal production in the target factory.

The results of the pilot study together with the results from the intensive laboratory studies suggest the feasibility of thermophilic anaerobic treatment for the studied wastewaters.
An effects-based approach to regulating the pulp and paper industry: the New Zealand scene
Authors: Dell P. , Donald R. , McIntosh J.
Published: May 2018

New Zealand's primary environmental legislation, the Resource Management Act (RMA), was enacted in 1991. The RMA is effects based rather than activity based and is intended to promote the sustainable management of natural and physical resources. A number of New Zealand's pulp and paper mills are now coming under the permitting requirements of the RMA. The prime environmental concerns have been associated with the two kraft mills, and include dissolved oxygen, color, toxicity, nutrients and impacts on fisheries. This paper presents a case study of one of these mills and discusses the regulatory approach which is to be adopted under the constraints of the RMA.
Sensory evaluation of fish exposed to pulp and paper mill effluent: a case study of methods used for environmental effects monitoring
Authors: Redenbach A. E.
Published: May 2018

The federal Environmental Effects Monitoring (EEM) program, as a component of the Fisheries Act; Pulp and Paper Effluent Regulations, requires sensory evaluation at Canadian pulp and paper mills where there have been historical complaints of fish tainting or reduced fishing efforts and there is no potential health hazard. Sensory evaluation tests were conducted at three mills in British Columbia. Each test component yielded considerable variability. Nevertheless, there was a high degree of similarity between the mills for the tainting results. Significant tainting of two fish species occurred within three hours and at exposure concentrations less than 0.08% (v/v) effluent at one location. Adult and juvenile fish appear to be attracted to and reside in effluent plumes immediately downstream of the outfall at some mills. Tertiary treated effluent discharged from one mill continued to taint resident fish. Sensory evaluation may be the most sensitive monitoring tool available to assess and integrate effluent exposure with the usability of valuable sports, recreation, commercial and native fisheries resources. A proposal to focus EEM cycle 2 programs to evaluate the use of these fisheries resources is presented.
Bioaccumulation of dehydroabietic acid in rainbow trout (Oncorhynchus mykiss): role of biotransformation enzymes
Authors: Stuthridge T. R. , Anderson S. M. , Gifford J. S. , Robinson M. J. , Straus D. L.
Published: May 2018

The role of Phase I and Phase II metabolism in rainbow trout on the bioaccumulation of dehydroabietic acid, an abundant and persistent compound found in pulp and paper mill effluents, was investigated using known inducer/inhibitor compounds for cytochromes P450 (P450s), ethoxyresorufin O-deethylase (EROD) and uridine diphosphoglucuronosyltransferase (UDPGT). The inducer/inhibitor compounds consisted of piperonyl butoxide (PBO), salicylamide (SAL) and β-naphthoflavone (βNF). PBO induced EROD, SAL had no effect on the measured biotransformation enzyme activities and βNF induced EROD and UDPGT. Treatment of trout with these compounds altered the bioaccumulation and distribution of dehydroabietic acid (DHAA) between bile, liver, and muscle in trout exposed to both the pure compound and an untreated mill effluent indicating that biotransformation enzyme activities may directly influence these bioconcentration processes in recipient biota.
Acute toxicity to fish and solution stability of some biocides used in the pulp and paper industry
Authors: Milanova E. , Sitholé B. B.
Published: May 2018

Acute toxicities of four biocide compounds and their formulations to rainbow trout have been determined. The 96-hour LC50 values of bis-trichloromethyl-sulfone (BTMS), β-bromo-β-nitrostyrene (BNS), methylene-bis-thiocyanate (MBT), and a mixture of isothiazolinones (ISO) were 0.02, 0.05, 0.09, and 0.2 ppm, respectively. Stabilities of individual compounds in an effluent and in aqueous solution have also been investigated. The results show that BNS and MBT were not stable, BTMS volatilized into the open atmosphere, and ISO remained stable under the experimental conditions employed.
Benthic community populations near two adjacent northern pulpmill discharges
Authors: Thomas G. P. , Munteanu N.
Published: May 2018

Benthic invertebrate communities were investigated as part of the federal Environmental Effects Monitoring programs conducted as required by the amended Pulp and Paper Effluent Regulations (PPER) of the federal Fisheries Act. A Refiner Mechanical (RMP) and larger Kraft pulpmill, both situated on a northern, BC reservoir, discharge secondary-treated effluent within 5 km of each other. Efforts to independently distinguish potential effects associated with these individual discharges were complicated by the proximity of the diffusers, their location within a complex ecological region of a reservoir, and the presence of temporal and spatial confounding influences. A comprehensive examination of the benthic community structure involved the combined assessment of several endpoints (total population numbers, relative proportion of taxonomic groups, and species richness). A tiered, spatial approach, based on a reservoir ecological model (Thornton et al., 1981), was adapted to assess and distinguish community structures and reservoir- and mill-related influences. Results suggested that effects associated with the two different mills could be distinguished based on subtle and distinct differences in benthic community profiles.
Economic analysis of waste minimization for electroplating plants
Authors: Lo Shang-Lien , Tsao Ya-Chi
Published: May 2018

The purpose of this study was to investigate the application of waste minimization technology to electroplating plants and to evaluate the economic aspects of such an application. Waste minimization in electroplating plants can be classified into two categories: recycling and source reduction. Generally, source reduction takes priority before the other and is the most economic tool for waste minimization. Reduction of spent cleaning solutions and drag-out minimization are two major tasks, in which 86% and 60%, respectively, of the plants reviewed were involved, while 74% of the electroplating plants utilized purification equipment to recycle raw materials. In the electroplating process, some heavy metals and rinse water can be recycled. Most of the plants that were investigated recycle the effluent water to the rinse process for further use. From the results of the case study, the cost of the equipment and the utilization rate of the facilities have greater influence on the net present value (NPV) than other factors. Therefore, if the cost or the utilization rate of the facilities varies, re-evaluation will be needed.
Reductive transformation of tetrachloroethylene to ethylene and ethane by an anaerobic filter
Authors: Komatsu Toshiya , Shinmyo Jun , Momonoi Kiyoshi
Published: May 2018

Tetrachloroethylene (PCE) is one of the most common groundwater contaminants in Japan. PCE can be completely dechlorinated to ethylene (ETY) and ethane (ETA) by anaerobic microorganisms in the presence of a suitable electron donor. This study was conducted to examine the feasibility of using an anaerobic filter for the degradation of PCE in a bioremediation process. Laboratory-scale anaerobic filters were operated at 25°C using ethanol as the electron donor. Rapid start-up of the reactors was achieved by using anaerobic completely PCE-dechlorinating enrichment cultures as the inoculum. During the continuous operating periods, low concentrations (2.8 mg/L) of PCE were almost completely dechlorinated to ETY and ETA at hydraulic retention times of 49-15 hours with 100 mgCOD/L of ethanol. PCE concentrations as high as 80 mg/L was dechlorinated to ETY with a relatively low supply (200 mgCOD/L) of ethanol. Results of this study suggest that the anaerobic filter system is a feasible bioremediation process for the cleanup of groundwater which is contaminated by chlorinated ethylenes.
Structure and methanogenic activity of granules from an ASBR treating dilute wastewater at low temperatures
Authors: Banik Gouranga C. , Ellis Timothy G. , Dague Richard R.
Published: May 2018

The microstructure of ASBR granules treating synthetic substrate consisting of non-fat-dry-milk at temperatures of 5, 15 and 25°C was analyzed by scanning and transmission electron microscopy. The specific methanogenic activity of the granules was tested at 35°C using acetate and mixtures of acetate and propionate as substrates. Results revealed no significant variation in microbial structure for the different temperature conditions. Granules at 15 and 25°C exhibited uniform structure, predominantly Methanothrix-like microorganisms, while granules at 5°C indicated the existence of a layered structure. This reinforces the hypothesis that layering is largely substrate specific, but also suggests that temperature may have a role. Activity tests revealed that even after long periods of operation at psychrophilic temperatures, mesophilic bacteria are active and have the ability to rapidly degrade acetate and mixtures of acetate and propionate.
Simple black box models predicting potential control parameters during disturbances to a fluidised bed anaerobic reactor
Authors: Premier G. C. , Dinsdale R. , Guwy A. J. , Hawkes F. R. , Hawkes D. L. , Wilcox S. J.
Published: May 2018

Models of the anaerobic digestion process which predict digester behaviour sufficiently accurately could be used in process control. Although the process is generally considered to be non-linear, it could possibly be represented by an adaptive linear model, where the model adapts rapidly enough to represent the process at differing operating conditions and times in its operating life. Simple linear black box models of low order were investigated, predicting over a limited horizon and relying on current and recent data values to refine the prediction. Independent black box ARX models were identified for gas production rate, % CO2, bicarbonate alkalinity and Total Organic Carbon using on-line data from a fluidised bed reactor at varying organic load. Model predictions looked ahead one sample step (30 minutes) and when validated using data obtained in a different time period (separated by 4-8 weeks) gave significant predictions in each case. All the models consisted of only second or third order polynomials. The non-linear nature of the process was found to have little effect over the operating conditions investigated. Also the variation of the process within a 4-8 week period was not sufficient to cause the models to predict badly.
The treatment of iron oxalate leach liquors in a UASB with sulfate reduction
Authors: Teer J. E. , Leak D. J. , Dudeney A. W. L. , Narayanan A. , Stuckey D. C.
Published: May 2018

The presence of small amounts of iron (>0.013% Fe) in sand creates problems in the manufacture of high quality glass. Removal by hot sulphuric acid is possible, but creates environmental problems, and is costly. Hence organic acids such as oxalic have been investigated since they are effective in removing iron, and can be degraded anaerobically. The aim of this work was to identify key intermediates in the anaerobic degradation of oxalate in an upflow anaerobic sludge blanket reactor (UASB) which was removing iron from solution in the sulphide form, and to determine the bacterial species involved. 2-bromoethanesulfonic acid (BES) and molybdenum were selected as suitable inhibitors for methanogenic and sulphate reducing bacteria (SRB) respectively. 40mM molybdenum was used to inhibit the SRB in a reactor with a 12hr HRT. Total SRB inhibition took place in 20 hrs, with a complete breakthrough of influent sulphate. The lack of an immediate oxalate breakthrough confirmed Desulfovibrio vulgaris subspecies oxamicus was not the predominant oxalate utilising species. Nevertheless, high concentrations of molybdenum were found to inhibit oxalate utilising bacteria in granular reactors but not in suspended population reactors; this observation was puzzling, and at present cannot be explained. Based on the intermediates identified, it was postulated that oxalate was degraded to formate by an oxalate utilising bacteria such as Oxalobacter formigenes, and the formate used by the SRBs to reduce sulphate. Acetate, as a minor intermediate, existed primarily as a source of cell carbon for oxalate utilising bacteria. Methanogenic inhibition identified that 62% of the CH4 in the reactor operated at 37°C originated from hydrogenotrophic methanogenesis, whilst this figure was 80% at 20°C. Possible irreversible effects were recorded with hydrogenotrophic methanogens.
Modelling methanogenesis during anaerobic conversion of complex organic matter at low temperatures
Authors: Vavilin V. A. , Lokshina L. Ya. , Rytov S. V. , Kotsyurbenko O. R. , Nozhevnikova A. N. , Parshina S. N.
Published: May 2018

Low temperature consumption of H2/CO2 by microflora of tundra wetland soil and pond silt were simulated using the modified  model with consideration of homoacetogens or hydrogen consuming methanogens as hydrogenotrophs. Simulations show that the model with homoacetogens was able to fit the data closely. Under the conditions of high initial hydrogen concentrations acetate was the main precursor of methane. Inhibition of acetoclasic methanogens proved to be significant for tundra soil samples. Methane formation from organic matter contained in the samples of tundra soil was modeled in the wide range of temperature conditions. It was concluded that hydrolysis is the rate-limiting step at 10–28°C, but at 6°C the rate of acetoclastic methanogenesis becomes the rate-limiting stage in methane production. To describe the low temperature methane formation from organic matter by microflora of pond silt, cattle's and pig's manure the alternative pathways with participation of homoacetogens or hydrogenotrophic methanogens were verified. It was shown that the both pathways fit the measured data comparatively well.
Time series modelling of overflow structures
Authors: Carstensen Jacob , Harremoës Poul
Published: May 2018

The dynamics of a storage pipe is examined using a grey-box model based on on-line measured data. The grey-box modelling approach uses a combination of physically-based and empirical terms in the model formulation. The model provides an on-line state estimate of the overflows, pumping capacities and available storage capacity in the pipe as well as predictions of future states. A linear overflow relation is found, differing significantly from the traditional modelling approach. This is due to complicated overflow structures in a hydraulic sense where the overflow is governed by inertia from the inflow to the overflow structures. The capacity of a pump draining the storage pipe has been estimated for two rain events, revealing that the pump was malfunctioning during the first rain event. The grey-box modelling approach is applicable for automated on-line surveillance and control.
Characteristics of stormwater runoff and its control in Japan
Authors: Uchimura Konomu , Nakamura Eiichi , Fujita Shoichi
Published: May 2018

To improve the living environment in Japanese cities, both combined type and separate type sewer systems are being provided to cope with rainwater and sewerage. However, during heavy rain, overflows are causing pollution of the rivers or lakes at the discharge destinations.

In response to this problem, river management authorities in Japan have been studying the discharge load on combined sewer systems during rainfall and have established a simulation method to enable its prediction. As a result, the control of discharge loads by means of detention ponds has been effectively carried out in various cities in Japan.

In addition, in recent years the separate system, that was thought to result in relatively good water quality, has been found to cause adverse effects as a non-point source of pollution in lakes and rivers at discharge destinations. For this reason, simulation models are being developed for the case of separate systems for several cities to accurately determine the discharge loads during rainfall.

In this paper, as well as describing the discharge loads and control during rainfall for combined sewer systems in Japan, a report is given of the results of new research in regard to the discharge loads occurring in the case of separate sewer systems.
Acute pollution of recipients in urban areas
Authors: Rauch W. , Harremoës P.
Published: May 2018

Oxygen and ammonia concentration are key parameters of acute water pollution in urban rivers. These two abiotic parameters are statistically assessed for a historical rain series by means of a simplified deterministic model of the integrated drainage system. Continuous simulation of the system performance indicates that acute water pollution is caused by intermittent discharges from both sewer system and wastewater treatment plant. Neglecting one of them in the evaluation of the environmental impact gives a wrong impression of total system behavior. Detention basins and alternative operational modes in the treatment plant under wet weather loading have a limited positive effect for minimizing acute water pollution.
Vortex separator: proposal of a dimensioning method
Authors: Weiß Gebhard J.
Published: May 2018

An easy method is proposed to determine the necessary volume of a vortex separator in comparison to that of a first-flush CSO tank. The method is based on a simplified hydrological approach as well as on steady-flow efficiency data of the vortex separator which are derived from model tests. Transfer to prototype scale is done using efficiency measurements at a real separator. The method works with a balance of spilled COD loads and yields typically separator volumes of 50-70% of that of a conventional CSO tank.
Quantitative assessment of improvements in hydrological water cycle in urbanized river basin
Authors: Imbe M. , Ohta T. , Takano N.
Published: May 2018

Urbanization generally causes expansion of urban areas, improvement of lifestyles, high population density and high levels of land utilization. Those urbanization processes have resulted in an expansion of impermeable areas such as roofs and pavements, an increase in water demand, an increase in industrial and domestic waste water and a reduction of water surface areas and green lands.

The above-mentioned phenomena tend to distort the appropriate hydrological water cycle and derive the six issues to be solved which were pointed out in our previous paper Imbe et al.(1995). Six issues were described as: 1) Maintenance of Ordinary Water Discharge; 2) Flood Control; 3) Conservation and Development of Water Resources; 4) Conservation and Revival of Ecological System; 5) Pollution Control; 6) Improvement of Heat Environment.

In order to prevent the deterioration of the hydrological water cycle, many relevant measures are taken into account and the effect of those measures should be evaluated before the implementation. This paper presents a practical example of the evaluation procedure through a case study of the actual urbanized river basin called Azuma River.
Radar-aided CSO-control-criteria for an ecological approach
Authors: Petruck A. , Sperling F.
Published: May 2018

The control strategy of a combined sewer system incorporating three stormwater storage tanks with overflows presented here attempts to consider all aspects of acute CSO effects. These are the hydraulic and the composition components as well as the time factor. The result is an integrated approach, which is not based on the classic emission view (i.e. reduction of volume), but on pollution criteria (i.e. possible harm to the biotic community). The aim is to reduce the exceeding of critical peak values of the CSO components at critical time intervals.

Control decisions will be based on continuous measurements in the sewer system and in the receiving stream. Furthermore the measurements are carried out to determine the effects (both hydraulic and chemical) of particular CSO discharges in order to evolve the critical values for the project area. The chemical and physical measurements are accompanied by a biological monitoring programme. Macroinvertebrates are sampled upstream and downstream of outfalls and at a reference site. This allows the evaluation of the control measures on an ecological basis, and thus an assessment of the ecological potential of radar-aided real-time control of the combined sewer systems.
Emission-immission based design of combined sewer overflows and treatment plant - the dresden case study
Authors: Fuchs L. , Gerighausen D. , Schneider S.
Published: May 2018

For the city of Dresden a general master plan was set up based on investigations of the hydraulic capacity of the sewer system, the loads from combined sewer overflow and the treatment plant. The total emission from combined sewer overflows and treatment plant was the main criteria for the analysis of the efficiency of different renovation alternatives. The effect of the different alternatives on the quality of the receiving waters was investigated with a water quality model and evaluated with different approaches.
The inspection of actual runoff control facilities five years after construction
Authors: Akagawa Yuzo , Matsumoto Yasutoshi , Zaizen Mitsuyoshi
Published: May 2018

This report describes runoff control facilities (five years after construction) which are basically an athletic field consisting of tennis courts, constructed in an area of about four hectares in Tokyo. The report is divided into three parts. The first part deals with the social background of the fact that the athletic field has come to have runoff control functions. The second part concerns the summary of these facilities, and then the last part relates to the effects of runoff control. Concerning the effects of the facilities, the return period of design rainfall for runoff control facilities is ten years, but stormwater has been stored on the tennis courts twice in five years after construction. Though these two cases of rainfall were very extraordinary, as the outcome of the inspection of the runoff control facilities we were able to confirm the effects of runoff control by means of simulating under the condition of those two cases of rainfall. In addition, we were able to confirm the effect of groundwater cultivation by means of researching the transition of the groundwater table.
Evaluation of a portable water purification system for the removal of enteric pathogens
Authors: Naranjo J. E. , Chaidez Cl. , Quiñonez M. , Gerba C. P. , Olson J. , Dekko J.
Published: May 2018

The need for personal and potable water treatment devices has evolved from consumer interest in improving and ensuring the quality of drinking water. Such devices are especially useful to hikers and campers who often must use available surface water supplies. A portable iodinated water purification system was evaluated for the ability to inactivate/remove Klebsiella terrigena, poliovirus type 1, rotavirus SA-11 and Cryptosporidium oocysts under a variety of different water quality conditions: <1.0-10mg/L total organic carbon, turbidity <1-30NTU and total dissolved solids 200-1,500mg/L. The units were tested at room temperature and 4°C. The results showed that the system can achieve a geometric average removal of 6 log10 for Klebsiella terrigena, 4 log10 for poliovirus type 1 and rotavirus SA-11, and 3 log10 of Cryptosporidium oocysts.
Photocatalytic bactericidal activity of TiO2 in aqueous suspensions of E. coli
Authors: Bekbölet M.
Published: May 2018

Aqueous suspensions of Escherichia coli and TiO2 (anatase) were irradiated with a BLF lamp (320nm<λ<420nm). The inactivation rate for an initial E. coli level of 103 cells/mL was 1.78×10−2/min for light intensity of 67.9μE/s.m2 in the presence of 1mg/mL TiO2. Optimum TiO2 loading and the effect of light intensity are also reported.
UV ability to inactivate microorganisms combined with factors affecting radiation
Authors: Shaban A. M. , El-Taweel G. E. , Ali G. H.
Published: May 2018

In the present study, the effect of UV radiation on the inactivation of a range of microorganisms was studied. Each organism was seeded into sterile tap water and exposed to UV in batch experiments with changing turbidities. In addition, the effect of UV on microbial communities in river Nile water was examined. It was found that 1min contact time (0.5L/min flow rate) was effective against vegetative cells levels almost reaching zero (except with Staphylococcus aureus). On the other hand, spore-forming bacteria, Candida albicans and coliphage were more resistant to UV. This contact time caused coenobia cells in single form with Scenedesmus obliquus while for Microcystis aeruginosa colonies broke into smaller groups. Exposure of Nile water microbial communities to UV showed that yeasts and Aeromonas survived better than the other organisms while in the phytoplankton partial fragmentation occurred in some algal groups. The protective effect of turbidity differed between organisms, with increased contact time under conditions of stable turbidity having no effect on the organisms. At 20 NTU the UV radiation had no effect on the morphological characters of algal cells. In reactivation experiments, it is clear that photoreactivation, and not dark repair, takes place with bacterial cells. Only coliphage had no photoreactivation and dark repair responses although with coliphage and host, both reactivation processes worked well. Moreover, the irradiated algae regained their normal shape after 3 days in suitable media and enough light.
A situational analysis of the microbial water quality in a peri-urban catchment in South Africa
Authors: Venter S. N. , Steynberg M. C. , de Wet C. M. E. , Hohls D. , du Plessis G. , Kfir R.
Published: May 2018

A situational analysis of a peri-urban catchment experiencing microbial water quality problems was carried out using data collected over two and a half years. The water and land use in the area was determined. The main sources of pollution were identified and the effects of dilution and bacterial die-off on water quality were evaluated by modelling the level of faecal coliforms along the length of the river using the QUAL2E model. As a result of the assessment, water quality goals were set for the catchment and suggestions were made for the improvement of microbial quality. Certain areas of the catchment are densely populated and both developed and informal settlements exist. Water is mainly used for domestic and recreational purposes. The river receives diffuse source discharges as well as point source discharges from four wastewater treatment plants and an industrial site. Assessment of indicator organism and pathogen analyses indicated that the main factors affecting the microbial quality were discharges from the sewage plants and runoff from informal settlement areas. The industrial activities in the catchment did not have a major effect. Modelling runs predicting faecal coliform levels demonstrated that bacterial die-off did not result in a significant improvement to the microbial water quality in the catchment.
Sources of faecal indicator bacteria in a brackish, tropical stream and their impact on recreational water quality
Authors: Roll B. M. , Fujioka R. S.
Published: May 2018

This study assessed the contribution of water from a stream on the microbial quality of a swimming beach. The faecal indicator bacterial concentrations/100mL in Kaelepulu Stream greatly exceeded the three USEPA recreational water quality standards (200 faecal coliform, 126 E. coli, 33 enterococci). The primary sources for these indicator bacteria were determined to be environmental/non-point sources (tributary streams, storm drains, duck faeces, soil, rain). Sewage discharge is another, although sporadic source. Monitoring waters for C. perfringens was the most reliable indicator of sewage contamination primarily because soil is not a major source of this bacterium. Water from this inland system was a source of faecal indicator recovered from shoreline water samples obtained from Kailua Beach, one of the most popular beaches in the state of Hawaii.
The disinfection of wastewater by ultraviolet light
Authors: Moreno B. , Goñi F. , Fernandez O. , Martínez J. A. , Astigarraga M.
Published: May 2018

The aim of this study, carried out over four months at a pilot wastewater treatment facility, was to evaluate ultraviolet treatment of final effluent discharged into bathing waters in coastal zones. Minimum disinfection values were fixed with a target limit of 103cfu/100mL for faecal coliforms (FC) in line with the present and proposed European Directive on bathing water quality. Disinfection performance with different sources of water was studied and the disinfectant capacity with other indicator microorganisms was also checked. The target limit was reached using doses around 30mW.s/cm2. Results of this study suggest that the applied UV dose is influenced by transmittance and the microbiological load. The most sensitive indicators were faecal coliforms, the specific F-RNA bacteriophages being the most resistant. From the results obtained in these experiments, UV treated water is suitable for being discharged into bathing zones, being an alternative to submarine discharges, avoiding high investment and maintenance costs.
Chlorine sensitivity of environmental, distribution system and biofilm coliforms
Authors: Sartory D. P. , Holmes P.
Published: May 2018

Coliform bacteria, isolated from treated drinking water supplies, can be derived from a range of sources (e.g. infiltration, breakthrough at the treatment works or from the biofilm established within the pipework). The sensitivity of these bacteria to chlorine may be related to their source and metabolic status. Strains of coliforms were isolated from sewage works effluents, river and reservoir waters as well as from the bulk water and biofilms from distribution systems. These were assayed for sensitivity to free and total chlorine using two assay procedures. For E. coli, the isolates from the distribution system bulk water showed greater resistance to free chlorine than those from sewage effluents and equivalence to those from river waters. For non-E. coli coliforms (mainly strains of Klebsiella, Enterobacter and Citrobacter), those from distribution system biofilms showed the greatest sensitivity to free and total chlorine whilst those from river water had the greatest resistance.
Removal of Cryptosporidium from river water by crossflow microfiltration: a pilot-scale study
Authors: Drozd C. , Schwartzbrod J.
Published: May 2018

The major advantage of microfiltration in water treatment is the ability to clarify and decontaminate water in one step. A pilot tangential microfiltration system (a tubular ceramic membrane porosity 0.2μm, surface area 0.135m2) was tested for Cryptosporidium removal. Samples (2201) of artificially contaminated river water were filtered and a removal rate >4.3 log was obtained in nine tests. The viability of rejected oocysts was simultaneously conducted as it is important to be aware of the infectious potential of microfiltration concentrates produced and discharged into the environment. Oocyst viability was unaltered in the rejected concentrates after a normal filtration cycle. However, the process of membrane unclogging by sequential washing with NaOH and HNO3 proved to significantly decrease the number of surviving oocysts in rejected water. Indeed, the washing solutions collecting with the filtration concentrates before disposal resulted in a significant decrease of the viability of oocysts measured by inclusion/exclusion of fluorogenic vital dyes (DAPI and PI).
Evaluation of flow-cytometry for the monitoring of infectious human rotavirus in water
Authors: Abad F. X. , Bosch A. , Comas J. , Villalba D. , Pintó R. M.
Published: May 2018

A method has been developed for the detection of infectious human rotavirus (HRV), based on infection of MA104 and CaCo-2 cell monolayers and ulterior flow cytometry. The sensitivity of the flow cytometry procedure for the cell-adapted HRV enabled the detection of 200 and 2 MPNCU in MA104 and CaCo-2 cells, respectively. Flow cytometry performed five days after infection of CaCo-2 enabled the detection of naturally occurring wild-type HRV in faecal samples and concentrated water samples.
Water virology external quality assurance scheme: experiences over four years
Authors: Sellwood J. , Shore J.
Published: May 2018

The Water Virology External Quality Assurance (EQA) Scheme has distributed samples containing enterovirus to the specialised virus laboratories in Britain which analyse recreational water. Duplicate samples were either assayed for direct virus count or added to 101 of water, concentrated to 10ml and then assayed for virus counts. Although similar counts were obtained in different laboratories on direct assays, a wide range of virus counts was reported after water processing. However, robust attention to method detail and stringent quality control has been shown to improve the consistency of virus recovery rates. The results of tests for enterovirus in recreational water can then be used with confidence.
Removal of nitrogen from coal gasification wastewater by nitrosofication and denitrosofication
Authors: Liu Junxin , Li Weiguang , Wang Xiuheng , Liu Hongyuan , Wang Baozhen
Published: May 2018

In this paper, a study of a new process with nitrosofication and denitrosofication for nitrogen removal from coal gasification wastewater is reported. In the process, fibrous carriers were packed in an anoxic tank and an aerobic tank for the attached growth of the denitrifying bacteria and Nitrobacter respectively, and the suspended growth activated sludge was used in an aerobic tank for the growth of Nitrosomonas. A bench scale test has been carried out on the process, and the test results showed that using the process, 25% of the oxygen demand and 40% of the carbon source demand can be saved, and the efficiency of total nitrogen removal can increase over 10% as compared with a traditional process for biological nitrogen removal.
Implementation of the biological nutrient removal program at Calgary's Bonnybrook wastewater treatment plant
Authors: Wilson A. W. , Do P. , Keller W. E.
Published: May 2018

This paper describes the biological nutrient removal (BNR) program that has been implemented in stages at Calgary's Bonnybrook wastewater treatment plant (WWTP) over the past eight years. Process design parameters and performance data for two retrofit BNR projects and one new BNR expansion project are described. These projects have made the Bonnybrook WWTP the largest cold weather, suspended growth BNR plant in the world.
Controlling sulfide generation in force mains by air injection
Authors: Ochi Takatoshi , Kitagawa Mitsuo , Tanaka Syuji
Published: May 2018

Air injection into force mains has been used to control sulfide generation. However, the design criteria have not been clearly established. In this study, the minimum concentration of dissolved oxygen (DO) required to prevent sulfide generation, and the oxygen balance in the force mains were investigated using an experimental facility. Air injection completely eliminated sulfide presence at the pipe outlet when DO at the pipe end was 0.2 mg/l or higher. Reaeration from gaseous phase to wastewater was affected by sewage flow velocity and oxygen concentration in the gaseous phase. Oxygen consumption rate in bulk water (Rr) ranged widely from 3 to 18 mg/l.h. Oxygen consumption rate in biofilm (Re) was measured using a rotating reactor. Re seemed to increase in proportion to the square root of DO.
Wastewater treatment and nutrient removal in the combined reactor
Authors: Roš M. , Vrtovšek J.
Published: May 2018

A combined anaerobic anoxic aerobic reactor for the treatment of the industrial wastewater that contains nitrogen and complex organic compounds as well as its design procedure is presented.

The purpose of our experiments was to find a simple methodology that would provide combined reactor design. The reactor is based on the combination of anaerobic, anoxic and aerobic process in one unit only. It was found that the HRT even under 1 hour in the anaerobic zone is long enough for the efficient transformation of complex organic compounds into readily biodegradable COD which is then used in dentrification process. In the N-NO3 concentration range 1.5-50 mg/l the denitrification rate could be expressed as half-order reaction when the CODrb was in excess. N-NO3 removal efficiency is controlled by the recycle flow from the aerobic to the anoxic zone. Nitrification rate can be expressed as first, half or zero-order reaction with respect to effluent N-NH4 concentration. Nitrification rate depends on the dissolved oxygen concentration and hydrodynamic conditions in the reactor.

Case study for design of a pilot plant of the combined reactor for treatment of pre-treated pharmaceutical wastewater is shown. Characteristics of pre-treated wastewater were: COD=200 mg/l, BOD5=20 mg/l, N-Kjeldahl=80 mg/l, N-NH4=70 mg/l, N-NOx<1 mg/l, P-PO4=5 mg/l. Legal requirements for treated wastewater were: COD=<100 mg/l, BOD5<5 mg/l, N-NH4=<1 mg/l, N-NOx=<10 mg/l.
Effect of dissolved oxygen in reclaimed wastewater transformation during transportation. Case study: Tenerife, Spain
Authors: Delgado S. , Alvarez M. , Aguiar E. , Rodríguez-Gómez L.E.
Published: May 2018

During treated wastewater transport, phenomena related to the presence or absence of dissolved oxygen (DO) have been observed. In Tenerife reclaimed urban wastewater (RUWW) transport from the capital, Santa Cruz to the south of the island for agriculture reuse was studied. Anoxic conditions and H2S generation were noted during transport. As RUWW has an electrical conductivity (EC) of about 1600 μS/cm, BALTEN decided to add fresh water (FW) with low EC, saturated or over saturated in DO at an intermediate point in the pipe to reduce the conductivity of water supplied to agriculture, also thus reducing the organic load and consequently H2S generation. However, injection of DO over-saturated fresh water brought on the appearance of nitrification and later denitrification. A study was carried out of H2S generation, nitrification and denitrification during RUWW transport with and without added FW.
Determination of the inhibition of ammonia-N and urea-N oxidation by the fed-batch reactor (FBR) technique
Authors: Çeçen Ferhan , Ipek Suna
Published: May 2018

Nitrification of ammonium nitrogen and urea nitrogen was studied in a submerged biofilm reactor. The reactor was operated as a fed-batch reactor to which an excessive mass loading was applied. The increases in TKN, ammonium-N, NOx-N and NO2-N concentrations inside the reactor were investigated to assess inhibitory behaviour under non-steady state conditions. The maximum ammonium oxidation rate was about 60 mg NH4-N/h that corresponded to a surface removal rate of 8.5 g NH4-N/m2.d. The major factor for nitrite accumulation was the presence of free ammonia. In the oxidation of urea where the free ammonia concentrations were very small no nitrite accumulation was observed. Overall, the results showed that the fed-batch reactor technique could be applied to a nitrifying biofilm reactor to evaluate the effect of slug doses in a short time period.
A stochastic approach to modelling solid transport in settling tanks
Authors: Chebbo Ghassan , Forgues Nicolas , Lucas-Aiguier Emmanuelle , Berthebaud Stéphane
Published: May 2018

Dispersion and settling models for suspended solids (SS) in turbulent flow are in the majority of cases Eulerian and deterministic. They simulate SS transport using a convection-diffusion equation. When the diffusion term is supposed not to be zero at the boundary of a settling tank, we show that an alternative (or equivalent) description of the basic convection-diffusion equation for the concentration of suspended solids consists in modelling the particles trajectories as a stochastic diffusion process.

This paper has two aims, firstly to present the proposed stochastic approach and secondly to apply this new method to the calculation of a settling tank's efficiency.