bluuebunny/crossref_metadata_2025 huggingface dataset:
Sequential variation of groundwater quality in an agricultural area with greenhouses near the coast
Authors: Fujiwara T. , Ohtoshi K. , Tang X. , Yamabe K.
Published: May 2018

The quality of coastal groundwater utilized for greenhouse-farming is liable to be affected by not only fertilization practices but also seawater intrusion into the aquifer. In this study, the sequential variations of groundwater quality and the mechanisms of its pollution processes were analyzed through successive field measurements from June 2000 to May 2001 in such a coastal agricultural area located in Kochi prefecture, Japan. The analysis revealed that the ions for NO3−, SO42−, Mg2+ and Ca2+ in the groundwater originated primarily from the ground surface due to the seasonal flooding activities. It was also estimated that denitrification occurred at three well points, and the rate constants were 0.010, 0.019 and 0.089 d-1, respectively. Na+, Mg2+ and Ca2+ concentrations in the groundwater governed by seawater intrusion phenomena showed strong correlations with the concentration of Cl− by excluding the influence of fertilizer. Cation exchange phenomena between Ca2+ and Na+ and as well as the mixing with seawater had a considerable effect on the groundwater quality.
Combined biological and physico-chemical treatment of filtered pig manure wastewater: pilot investigations
Authors: Kalyuzhnyi S. , Sklyar V. , Epov A. , Arkhipchenko I. , Barboulina I. , Orlova O. , Klapwijk A.
Published: May 2018

Combined biological and physico-chemical treatment of filtered pig manure wastewater has been investigated on the pilot installation operated under ambient temperatures (15-20°C) and included: i) UASB-reactor for elimination of major part of COD from the filtrate; (ii) stripper of CO2 + fluidised bed crystallisator for phosphate (and partially ammonia) removal from the anaerobic effluents in the form of insoluble minerals - struvite (MgNH4PO4) and hydroxyapatite (Ca5(PO4)3OH); (iii) aerobic-anoxic biofilter for polishing the final effluent (elimination of remaining BOD and nutrients). Under overall hydraulic retention time (HRT) for the system of 7.8 days, the total COD, inorganic nitrogen and total phosphorous removals were 88, 65 and 74%, respectively. A decrease of the overall HRT to 4.25 days led to 91, 37 and 82% removals for total COD, inorganic nitrogen and total phosphorus removals, respectively. The approaches for further improvement of effluent quality are discussed.
Anaerobic digestion of organic waste in Japan: the first demonstration plant at Kyoto City
Authors: Komatsu T. , Kimura T. , Kuriyama Y. , Isshiki Y. , Kawano T. , Hirao T. , Masuda M. , Yokoyama K. , Matsumoto T. , Takeda M.
Published: May 2018

Recycling of Municipal Solid Waste is vigorously promoted in Japan and the necessity of energy recovery from organic waste is increasing. An anaerobic digestion demonstration plant for organic waste in Kyoto City, Japan has been operated for about two years. Three kinds of wastes (garbage and leftovers from hotels, yard waste and used paper) mixed at various ratios are used. The plant has maintained stable operations with each mixture, generating biogas by the decomposition of VS at the rate of about 820 m3N/ton-VS.
Nitrogen nutrient removals from wastewater and river water
Authors: Abdul-Rahman R. , Tsuno H. , Zainol N.
Published: May 2018

Elevated levels of nutrients in agroindustry wastewaters, and higher reliance on chlorination pose health threats due to formation of chlorinated organics as well as increased chlorination costs. Removals of ammonium and nitrate compounds were studied using activated carbon from palm shells, as adsorbent and support media. Experiments were carried out at several loadings, F:M from 0.31 to 0.58, and hydraulic residence times (HRT) of 24 h, 12 h and 8 h. Results show that the wastewater treatment process achieved removals of over 90% for COD and 62% for Total-N. Studies on removals from river water were carried out in sequencing batch reactor (SBR) and activated carbon biofilm (ACB) reactor. Removals achieved by the SBR adsorption-biodegradation combination were 67.0% for COD, 58.8% for NH3-N and 25.5% for NO3-N while for adsorption alone the removals were only 37.0% for COD, 35.2% for NH3-N and 13.8% for NO3-N. In the ACB reactor, at HRT of 1.5 to 6 h, removals ranged from 12.5 to 100% for COD, 16.7 to 100% for NO3-N and 13.5 to 100% for NH3-N. Significant decrease in removals was shown at lower HRT. The studies have shown that substantial removals of COD, NO3-N and NH3-N from both wastewater and river water may be achieved via adsorption-biodegradation by biofilm on activated carbon processes.
Purification of agro-industrial wastewater from the grease-protein mixture by means of electroflotocoagulation
Authors: Karpuzcu M. , Dimoglo A. , Akbulut H.Y.
Published: May 2018

The process of agro-industrial sewage treatment with the aim of extracting grease from the waters is studied by means of electroflotocoagulation. A method of optimising the construction of electroflotocoagulation apparatus for sewage treatment is offered that allows passing from a laboratorial model to an industrial specimen that possesses the same level of technological characteristics. Multiple examples are given of applying electroflotocoagulation technology for sewage treatment from proteins and grease under different conditions.
Control of bulking sludge caused by Type 021 N and Type 0961 in an industrial wastewater treatment plant with an aerobic selector
Authors: Duine A. , Kunst S.
Published: May 2018

Over a period of 6 months, pilot plant investigations were carried out with the purpose of bulking sludge control with different aerobic selectors. The wastewater was dominated by industrial dischargers, containing volatile fatty acids up to 450 mg/l. With complete-mix-selectors it was not possible to achieve a stable SVI below 150 ml/g. The bulking sludge could only be controlled with a sectionalized selector (HRT 5–8 minutes per section). The SVI decreased to values below 100 ml/g. Shock-loads and increased VFA-concentrations (by dosing NaC2H3OO) did not cause filamentous growth.
Implementation of glycogen accumulating bacteria in treating nutrient-deficient wastewater
Authors: Jobbágy A. , Literáthy B. , Tardy G.
Published: May 2018

Activated sludge treatment of nutrient-deficient wastes may lead to severe slime formation and consequent biomass separation difficulties. The purpose of this paper has been to show that bioreactor arrangement essentially influences the manner of biological excess carbon removal. In a comparative lab-scale experiment two differently arranged activated sludge systems were operated simultaneously: an aerated CSTR with an aerobic selector and an aerated CSTR with an anaerobic selector. The seed derived from an anaerobic/aerobic activated sludge plant of a winery. The model wastewater contained wine, sugar and acetic acid as organic carbon sources and lacked nutrients regarding both N and P, similarly to the influent of the full-scale plant.

During the 52 days of the experiment the SVI values of the fully aerated system increased up to 600–800 cm3 g−1 whereas those of the anaerobic/aerobic system remained below 250 cm3 g−1. The SVI values showed a strict correlation with the amount of extracellular polysaccharides. In the anaerobic/aerobic experimental system, the high (40% of MLSS) intracellular polysaccharide content of the seed could be maintained. Besides the analytical data, also the microscopic observations of the biomass structure referred to the presence of glycogen accumulating organisms in both the lab- and full-scale anaerobic/aerobic systems.
Differences in nitrification potential between fully aerobic and nitrogen removal activated sludge systems
Authors: Hatziconstantinou G.J. , Andreadakis A.
Published: May 2018

Experimental observations made on two pilot plants, showed that nitrogen removal activated sludge systems, operating under favourable conditions, seem to develop increased nitrification potential compared to fully aerobic systems under similar conditions. This increased potential, which cannot be detected by simple nitrification performance evaluations, is attributed to higher autotrophic populations sustained – developed in similar systems employing anoxic reactors or phases. A reduced autotrophic decay rate under anoxic conditions as reported by some researchers, seems to play a significant role in such a response, most likely together with a more efficient use of available nitrogen for additional nitrifying microorganisms production, resulting from a reduced nitrogen loss to autotrophic biomass maintenance needs and heterotrophic biomass synthesis requirements.
Modelling population dynamics of denitrifying phosphorus accumulating organisms in activated sludge
Authors: Spagni A. , Stante L. , Bortone G.
Published: May 2018

In this paper a kinetic model for simulating population dynamics is developed. The aim was to simulate anoxic and aerobic phosphorus accumulating organisms dynamics in a lab-scale sequencing batch reactor (SBR) operating under different conditions. Denitrifying phosphorus accumulating organisms (DNPAOs) successfully competed in almost all the simulated operational conditions tested. Using this model, the anoxic energy disadvantage of DNPAOs was not as strong as using metabolic models. The model was able to predict reasonably well N, P and acetate profiles in the SBR with only a minor modification of the ASM2d default values of the parameters.
Biomass active fraction evaluated by a direct method and respirometric techniques
Authors: Andreottola G. , Foladori P. , Gelmini A. , Ziglio G.
Published: May 2018

The knowledge of the active biomass amount and its characterisation is of primary importance for the management and for the design of wastewater treatment plants on the basis of the recently developed models. OUR curves obtained in aerobic exponential growth tests are proposed by several authors as an indirect method to estimate the active fraction. The aim of this work is the application of a direct method to measure the viable biomass based on flow cytometry techniques and the comparison with the active fraction obtained from respirometric tests. To assess the viable fraction of a biomass expressed in terms of COD concentration it is necessary to estimate the biovolume of viable bacteria and to know the specific carbon content per cell. For the investigated activated sludge samples, the bacterial biomass measured by FCM was 588 mgCOD L−1 on average in a two-months period. This value of active fraction corresponds to 14% of particulate COD. Active biomass values measured with the respirometric approach were consistent but generally higher than those obtained by FCM.
Characteristics of bacterial populations responsible for uptake of amino acids in activated sludge acclimated to peptone
Authors: Ubukata Y. , Takii S.
Published: May 2018

Amino acids (AAs) are produced from the hydrolysis of proteins, which are the major biodegradable organic compounds in municipal sewage. The characteristics of bacterial populations responsible for the assimilation of thirteen AAs into activated sludge (AS) acclimated to peptone are investigated. The results are as follows. (1) The bacterial populations responsible for the uptake of AAs were partly aggregated in AS flocs. (2) The amounts of the bacterial populations responsible for the uptake of leucine, valine, isoleucine, histidine, threonine, lysine and glycine are limited in AS acclimated to peptone. (3) The bacterial populations responsible for the uptake of phenylalanine, leucine and lysine were different. (4) The amounts of bacterial populations responsible for the uptake of aspartate, arginine, alanine, glutamate and phenylalanine are not limited. (5) The functions of the assimilation of these AAs were induced in many bacterial cells as a result of the BOD determination methods applied to these pure AAs.
Microbial evaluation of activated sludge and filamentous population at eight Czech nutrient removal activated sludge plants during year 2000
Authors: Krhutková O. , Ruzicková I. , Wanner J.
Published: May 2018

The long-term project on the survey of filamentous microorganisms, which started in 1996, was finished in 2000 by the survey of eight Czech activated sludge plants with biological nutrient removal (BNR) systems. At all plants with enhanced biological nutrient removal, specific microbial population (mostly from the point of view of filaments occurrence), operational problems (presence of biological foaming, bulking) and plant operation were observed periodically and longer than 1 year. In our paper the relationship between the composition of activated sludge (especially filaments) consortia and modification of the process with nutrient removal is discussed. At the surveyed plants Type 0092 and Microthrix parvicella were identified as dominant Eikelboom filamentous types.
Treatment of easily biodegradable wastewater avoiding bulking sludge
Authors: Matsché N. , Winkler S. , Prendl L. , Dornhofer K. , Wandl G.
Published: May 2018

The presence of easily degradable compounds from food industries frequently leads to bulking problems. The paper describes a new process that has been developed for a dairy in Austria. Because of the increase in production the treatment plant receiving the wastewater up to now was not able to handle the increased loads. Therefore detailed studies for treatment alternatives have been undertaken which led to a completely new concept. The excess sludge of the urban treatment plant is contacted with the concentrated dairy waste in a separate contact tank. In this tank the easily degradable substrate from the industrial waste is mainly adsorbed to the biological sludge and after a mechanical dewatering transferred to the anaerobic digester where it yields an increased gas production. The filtrate of the dewatering process is completely free from biodegradable material and can without danger of bulking be fed to the aeration tank. The process has been in operation for more than one year and has fulfilled all expectations.
Use pH and ORP as fuzzy control parameters of denitrification in SBR process
Authors: Peng Y.Z. , Gao J.F. , Wang S.Y. , Sui M.H.
Published: May 2018

In order to achieve fuzzy control of denitrification in a Sequencing Batch Reactor (SBR) brewery wastewater was used as the substrate. The effects of brewery wastewater, sodium acetate, methanol and endogenous carbon source on the relationships between pH, ORP and denitrification were investigated. Also different quantities of brewery wastewater were examined. All the results indicated that the nitrate apex and nitrate knee occurred in the pH and ORP profiles at the end of denitrification. And when carbon was the limiting factor, through comparing the different increasing rate of pH whether the carbon was enough or not could be known, and when the carbon should be added again could be decided. On the basis of this, the fuzzy controller for denitrification in SBR was constructed, and the on-line fuzzy control experiments comparing three methods of carbon addition were carried out. The results showed that continuous carbon addition at a low rate might be the best method, it could not only give higher denitrification rate but also reduce the re-aeration time as much as possible. It appears promising to use pH and ORP as fuzzy control parameters to control the denitrification time and the addition of carbon.
Enhancing biological phosphorus removal from municipal wastewater with partial simultaneous precipitation
Authors: Valve M. , Rantanen P. , Kallio J.
Published: May 2018

Pilot-scale tests to enhance phosphorus removal with ferrous sulphate in a biological phosphorus and nitrogen removal process (modified UCT) for treating municipal wastewater were performed. The results indicated that Fe(II) competes with the BioP organisms and will inhibit the biological phosphorus removal process completely at doses exceeding 9 g m−3 of Fe(II). The goal of an effluent P level of 0.5 mg l−1 can be attained with 5 g m−3 of Fe(II). A consistent effluent concentration of 0.3 mg l−1 could not be achieved with this method. A centrifugation method to evaluate the dewatering properties of sludge was developed. Comparison of the settling and dewatering properties between activated sludge from the pilot plant and a full-scale simultaneous precipitation process indicated no consistent differences between them. The poor settling properties are due to the long sludge retention time needed by nitrification and not to the biological phosphorus removal process.
A supervisory control system for optimising nitrogen removal and aeration energy consumption in wastewater treatment plants
Authors: Serralta J. , Ribes J. , Seco A. , Ferrer J.
Published: May 2018

A fuzzy logic supervisory control system for optimising nitrogen removal and aeration energy consumption has been developed. This control system allows optimising and controlling the dissolved oxygen (DO) concentration in the aerobic reactors, the blowers discharge pressure and the effluent ammonia and nitrate concentrations. DO is controlled by adjusting control valve opening and blower discharge pressure is controlled by modifying rotational speed of the blowers. Optimum nitrification/denitrification is achieved by modifying the DO set point in the last aerobic reactor and the internal recirculation.

This system has been tested by simulation in a Bardenpho process using the Activated Sludge Model No2. A significant improvement in stability on the activated sludge process is achieved. Moreover, significant energy saving has been achieved with this control strategy.
Storm water management in an urban catchment: effects of source control and real-time management of sewer systems on receiving water quality
Authors: Frehmann T. , Nafo I. , Niemann A. , Geiger W.F.
Published: May 2018

For the examination of the effects of different storm water management strategies in an urban catchment area on receiving water quality, an integrated simulation of the sewer system, wastewater treatment plant and receiving water is carried out. In the sewer system real-time control measures are implemented. As examples of source control measures the reduction of wastewater and the reduction of the amount of impervious surfaces producing storm water discharges are examined. The surface runoff calculation and the simulation of the sewer system and the WWTP are based on a MATLAB®/SIMULINK® simulation environment. The impact of the measures on the receiving water is simulated using AQUASIM. It can be shown that the examined storm water management measures, especially the source control measures, can reduce the combined sewer overflow volume and the pollutant discharge load considerably. All examined measures also have positive effects on the receiving water quality. Moreover, the reduction of impervious surfaces avoids combined sewer overflow activities, and in consequence prevents pollutants from discharging into the receiving water after small rainfall events. However, the receiving water quality improvement may not be seen as important enough to avoid acute receiving water effects in general.
Integrated watershed approach for combating drought in a semi-arid region of India: the case of Jhabua watershed
Authors: Singh A.K. , Eldho T.I. , Prinz D.
Published: May 2018

The integrated watershed management approach for the semi-arid regions of India is considered to be very important due to the inadequate availability of water resources. The drought experienced in recent years has brought on an environmental and socio-economic crisis in these regions. The role of the watershed management has been crucial and development of alternative water resources has been critically important. To overcome the isolated sectoral development planning and implementation, as was done in many of the previous land based programs in India, an integrated concept of watershed development through participatory planning and actions has been followed for combating drought in Jhabua watershed in Madhya Pradesh state, India. This research paper will look into the successful watershed management experience of our on-going research project, and appropriate watershed strategies for the Jhabua watershed.
Integrated management of the Upper Mersey river basin using the SMILE object-oriented software system
Authors: Spanou M. , Chen D.
Published: May 2018

This paper presents the application of the object-oriented framework SMILE to the management of flows and water quality in the Upper Mersey river catchment. The design river flows are those exceeded for 95% of the time, and are estimated applying alternative methods. The influence of compensation reservoirs, surface-water abstractions, and continuous discharges on low river flows is quantified. The annual licensed abstraction volumes are further reviewed. The monitored river water quality is classified using the River Ecosystem scheme. The compliance of the sewage treatment works and trade effluents with their discharge-consent limits is also assessed. The impact of effluents on the variation of river water quality is evaluated through Monte Carlo simulations at the discharge points. The points where the downstream water quality fails to comply with proposed River Quality Objectives are identified. The consent limits of the corresponding discharges are assessed, and changes to the BOD and total ammonia limits are suggested.
The design of a web-based decision support system for the sustainable management of an urban river system
Authors: Chang Y.-C. , Chang N.-B.
Published: May 2018

The effects of urbanization on the aquatic environment, and solutions to the deterioration of water quality and stream ecology in the Love River have long been the main focus of environmental management in southern Taiwan. Apart from choosing the regular strategies of installing an intercept and sewer system, coastal wastewater treatment plant, and ocean outfall pipe, a new opportunity for improving the overall managerial efficiency is to design and implement a web-based Decision Support System (DSS). This DSS must be capable of managing storm water impacts when overflow is inevitable, river water quality variations leading to influences on the ecosystem, and changing land use programs along river corridors and adjacent urban areas simultaneously. This paper presents a new design framework for building such a DSS. By using the advanced information technology in the “Internet” environment, the proposed DSS may perform normal queries and statistical analyses in a web-enabled database, spatial analysis via the use of a Geographic Information System (GIS) in the Internet environment, and essential data warehousing/data mining. Possible linkage with various analytical models is anticipated. Such a DSS must be helpful for achieving the rehabilitation of the estuarine ecosystem and satisfying the goals for sustainable management in a regional sense.
Stormwater management in a catchbasin perspective - best practices or sustainable strategies?
Authors: Bäckström M. , Malmqvist P.-A. , Viklander M.
Published: May 2018

A strategy for sustainable stormwater management is needed. This study has focused on the relative importance of stormwater as a pollutant source in a catchbasin, if Best Management Practices (BMPs) result in pollutant removal or pollutant redistribution, and methods for screening of stormwater strategies. Stormwater is most likely an important pathway for pollutants in a catchbasin perspective. True pollutant removal can only be achieved if the pollutant sources are eliminated. Until that is reached, we should have the best possible control of the pollutant fluxes in the watershed. This study indicates that the search for a sustainable stormwater strategy could be easier to handle if different “screens” could be used. The Swedish environmental objectives, which try to encapsulate all aspects of sustainability, may be used as a foundation for a “sustainability screen”. By using this screen, the “unsustainable” features of different stormwater strategies could be pointed out. A “standards and legislation screen” will be based on the EU Water Framework Directive. As this study has shown, it is doubtful whether the conventional BMPs, such as stormwater ponds and infiltration facilities, produce a sufficient pollutant control.
Experience with integrated water quality management in the Wahnbach Watershed
Authors: Clasen J. , Krämer R.
Published: May 2018

This paper describes how integrated water quality management has been developed for Wahnbach reservoir and the experience which has been gained with this multi-barrier system. Different measures in the catchment area, where co-operation with farmers was most important, are combined with the operation of a phophorus elimination plant, in which the main tributary is treated, and with aeration and biomanipulation in the reservoir. All measures together have led to the present oligotrophic state and the excellent hygienic condition of the reservoir.
Wastewater recycling concept for an urban multi-storey building
Authors: Herrmann T. , Hesse T.
Published: May 2018

An innovative system for blackwater recycling is described. An existing building comprising of 32 flats built in 1962 was renovated and equipped with vacuum toilets to collect blackwater separately. The energy and water consumption was determined. The flushing water consumption decreased from 40 l/p/d to 9 l/p/d.
Production of value added products from separately collected urine
Authors: Behrendt J. , Arevalo E. , Gulyas H. , Niederste-Hollenberg J. , Niemiec A. , Zhou J. , Otterpohl R.
Published: May 2018

For many reasons it is advantageous to collect urine separately and collection systems, so called “no-mix-toilets” exist. Therefore, this work deals with some methods to make use of this urine to produce value added products: IBDU and ammonia water. It could be shown that urea can be converted to IBDU only after concentrating urine. With air stripping and absorption ammonificated urine can be treated very effectively and a solution of 10% w/w of ammonia can be obtained.
Sewer rehabilitation strategy in Berlin
Authors: Jacobi D. , Sympher K.-J.
Published: May 2018

Berlin Wasserbetriebe is in need of a significant and longterm investment in the rehabilitation of its sewer system. With ratification of the European Standard EN 752 Part 5, comprehensive rules have been set out for the rehabilitation of drain and sewer systems: hydraulic performance, environmental impact and structural integrity of complete catchment areas are given equal consideration. Taking this into account, Berliner Wasserbetriebe has developed a sewer rehabilitation strategy. Economic aspects are integrated with a cost-benefit-analysis; the significance of the remaining useful life of a pipe section is examined.
Ozonation of Han River humic substances
Authors: Yu M.J. , Kim Y.H. , Han I. , Kim H.C.
Published: May 2018

This study investigated the characteristics of extracted humic substances (HS) which are ubiquitous in river waters and affect the treatment of the water. HS were extracted from the Han River and the samples obtained were analyzed before/after oxidation with the following analytical methods: DOC, THMFP, UV-abs, chemical composition, molecular weight distribution, IR. Ozonation experiments were conducted in batch-type reactors. Ozone dose was 1 mg/L and contact time was varied from 0 to 20 minutes. The fraction of hydrophobic matter was 56.0% of total organic carbon in the Han River and the ratio of humic/fulvic acids was 22.4/77.6, showing high fractions of aromatic and/or double carbon bond functional groups and high fractions of saturated aliphatic carbons. Oxygen fraction of Han HS was relatively high compared with other humic substances (Suwannee River humic and fulvic acids), which are consistent with the results of IR spectra. The IR spectra showed the increase in aliphatic groups by ozonation of the Han HS. Humic substances could not completely be oxidized to CO2, H2O etc., but were partly oxidized to low molecular weight matter (aliphatics, aldehydes, carboxylics, polysaccharides etc.), so low removal efficiencies in terms of DOC (31∼35% with 5 minute contact) were observed. For UV254, 5 minute or shorter contact showed more than 80% removal efficiencies.
Biological treatment characteristics of benzene and toluene in a biofilter packed with cylindrical activated carbon
Authors: Li G.-W. , Hu H.-Y. , Hao J.-M. , Zhang H.-Q.
Published: May 2018

The biodegradation of toluene and benzene in a biofilter using cylindrical activated carbon as the filler materials was studied. Three gas flow rates, i.e. 0.25, 0.50 and 0.75 m3/h, corresponding to empty bed gas residence of 75, 37.5 and 25 s, respectively, and total organic load lower than 400 g/m3.h were tested. The biofilter proved to be highly efficient in biodegradation of toluene and benzene, and toluene was more easily degraded than benzene. When each inlet load was lower than 150 g/m3.h, removal rate increased with inlet load and reached a maximum, which was 150 and 120 g/m−3.h for toluene and benzene, respectively. For inlet load higher than the maximum removal capacity conditions, the removal rate decreased with inlet load. Carbon dioxide concentration profile through the biofilter revealed that the mass ratios of carbon dioxide produced to the toluene and benzene removed were 2.15 g(CO2)/g(toluene) and 1.67 g(CO2)/g(benzene), which furthermore, confirmed the biodegradation performance in biofilter. The observation of biotic community demonstrated that the microbes consisted of bacillus, spore bacillus and fungi, of which the spore bacillus was dominant.
The nomographic design approach to recycled water treatment by the nitritation process
Authors: Gil K. , Choi E. , Yun Z. , Lee J. , Ha J. , Park J.
Published: May 2018

The side-stream generated recycled water in the wastewater treatment plants is characterized as high in both nitrogen concentration and fluctuation of load. Thus, the design approach for recycle water management became an important part of the biological nutrient removal system design. The application of nitrogen removal from recycled water using the nitritation process has recently been increased due to economical reasons associated with an effective carbon allocation as well as the minimization of aeration cost. The concept of nitritation reactor design related to an inhibition of nitrite oxidizer has not been fully practiced in reality because of the limited field experiences. In this paper, a new approach has been proposed to determine reactor size and oxygen requirement in nitritation process design. The SRT-based design approach has been examined based on a series of laboratory experiments.
Removal of suspended substances by coagulation and foam separation from municipal wastewater
Authors: Suzuki Y. , Maruyama T. , Tegane H. , Goto T.
Published: May 2018

A new method for solid-liquid separation for wastewater incorporating simple operation and shortened treatment time is necessary for improvement of sewage systems. In this study, removal of suspended solids from municipal wastewater by coagulation and foam separation using coagulant and milk casein was examined. By adding casein before the foam separation process, the removal of suspended substances was dramatically improved. The optimum condition for treating sewage was 20 mg-Fe/L of FeCl3, 3 mg/L of casein, and pH 5.5, which resulted in a removal rates of over 98% for turbidity and SS. A removal of 96-98% was also possible for phosphate and anionic surfactant. When PAC was used, the floc was also efficiently recovered in foam by the addition of casein. It became clear that coagulation and foam separation using casein as the collector is an effective method for removing suspended solids in municipal wastewater in a short time (within 10 min).
A mathematical model for the flotation of waste activated sludge
Authors: Fujisaki K. , El-Zahar M.
Published: May 2018

A mathematical model that describes a batch flotation process is presented. The model employed a similar method to the hindered settling of flocculated material. This idea is based on our experimental results that the time growth curves of separated liquor zone showed a similar character to the settling curve of flocculated material, when the vertical axis reversed. In this model, it is also assumed that the gas phase and solid phase have the same movement, that is microbubbles and solid sludge particles joined to form aggregated floc. By comparing the numerical prediction with experimental data, the usefulness of the model is confirmed and some examples of flotation simulation are demonstrated.
Environmental risk evaluation for anionic surfactants based on the characteristics of appearance of high concentration in rivers
Authors: Kobuke Y.
Published: May 2018

Environmental risk evaluation for anionic surfactants based on the characteristics of the appearance of a high concentration was developed together with statistical analysis of MBAS data in rivers of Hyogo Pref., western Japan. Annual average MBAS at different monitoring points generally decreased during past 10 years and their geometric mean reduced by 70%. This rate of decrease agreed well with that of estimated environmental loads of anionic surfactants in the study area. The proportions of monitoring point with high risk (risk ratio over 1.0) to fish increased in the order of the weakness of toxicity in both 1989 and 1998. Their proportions were 2% for acute toxicity, 17% for chronic toxicity and 66% for avoidance response in 1989, which surpassed the proportion evaluated using average concentration in all cases. The proportions for whole toxicities decreased in 1998, however, the proportion for avoidance response kept considerably high level (42%). These results indicated the usefulness of environmental risk evaluation for surfactants based on the characteristics of appearance of high concentration, and also suggested the need for field investigation for fish avoidance response.
Fate of coliphage in waste water treatment process and detection of phages carrying the Shiga toxin type 2 gene
Authors: Tanji Y. , Mizoguchi K. , Akitsu T. , Morita M. , Hori K. , Unno H.
Published: May 2018

Abundances of phages specific to Escherichia coli in the wastewater treatment process were analyzed. Relatively abundant coliphages were detected in sewage influent. Phages in the influent were found both suspended in liquid phase and attached on the solid particles. Phage concentration was not reduced in the settling tank without chemical agglutination. Anaerobic followed by aerobic treatment of the sewage reduced concentration of suspended phages. Almost no phage was detected as a suspended form in the aerobic tank. Most of the phages were detected as attaching form and were excluded by aggregation with sludge. Using an experimental approach based on the detection of Shiga toxin 2 (Stx 2) gene by a phage enrichment culture followed by nested PCR, bacteriophages carrying Stx 2 gene were detected in the influent, settling tank, and anaerobic tank. It was revealed that the presence of phages carrying Stx 2 gene is common in sewage and these phages are effectively eliminated through sewage treatment process.
Estrogen-like effect and cytotoxicity of chemical compounds
Authors: Katori Y. , Ksu Y. , Utsumi H.
Published: May 2018

Luciferase assay, cytotoxicity test and protein quantitative analysis were performed after the exposure of chemical compounds to MVLN cells that are utilized to detect the endocrine disrupting activity. These consequences indicate that the concentration is different between the estrogen receptor mediated proliferation of breast cancer cells and the estrogen receptor mediated transcription by chemical compounds.
Evaluation of estrogen-like activity on sewage treatment processes using recombinant yeast
Authors: Onda K. , Yang S.-Y. , Miya A. , Tanaka T.
Published: May 2018

Four sewage treatment plants based on an activated sludge process and a pilot scale plant for advanced sewage treatment located in Japan were evaluated for removal of estrogenic substances using in vitro recombinant yeast assay and chemical analysis. The results indicated that 17βl-estradiol (E2) significantly contributed to estrogen-like activity analyzed by yeast assay especially in secondary treated effluents. On the other hand, batch study showed that estrogen-like activity of spiked E2 was easily decreased by an activated sludge treatment. This result suggested that E2 concentrations measured by enzyme immunoassay (EIA) were interpreted as false positives in effluents, and that unknown estrogenic substances other than E2 might have contributed to estrogen-like activity in the secondary treated effluents. Further, in the pilot scale study, advanced sewage treatment processes such as a biological aerated filtration (BAF) process, an advanced oxidation process (AOP), were effective for the removal of those estrogenic activities contributed by unknown estrogenic substances in sewage secondary treated effluent.
Findings of the Beijing 2000 IWA chemical industries speciality conference
Authors: Englande A.J. , Bao X.
Published: May 2018

Critical Technologies to the World in the 21st Century: Pollution Control and Reclamation in Process Industries was a Chemical Industries Specialty Conference held in Beijing, China 18-22 September 2000. Set in China, the cradle of civilization, the conference hosted about 100 delegates from over twenty countries. Approximately 122 technical papers were presented covering a wide range of topic areas. This paper reviews significant findings presented. Perhaps the conference proceedings will serve as a point of reference for future evaluations and accomplishments. The 21st century offers both challenges and opportunities for progress towards sustainable development/production in the process industries. International cooperation and inter-disciplinary collaboration are essential for this goal to be realized.
Improved nutrient removal using in situ continuous on-line sensors with short response time
Authors: Ingildsen P. , Wendelboe H.
Published: May 2018

Nutrient sensors that can be located directly in the activated sludge processes are gaining in number at wastewater treatment plants. The in situ location of the sensors means that they can be located close to the processes that they aim to control and hence are perfectly suited for automatic process control. Compared to the location of automatic analysers in the effluent from the sedimentation reactors the in situ location means a large reduction in the response time. The settlers typically work as a first-order delay on the signal with a retention time in the range of 4-12 hours depending on the size of the settlers. Automatic process control of the nitrogen and phosphorus removal processes means that considerable improvements in the performance of aeration, internal recirculation, carbon dosage and phosphate precipitation dosage can be reached by using a simple control structure as well as simple PID controllers. The performance improvements can be seen in decreased energy and chemicals consumption and less variation in effluent concentrations of ammonium, total nitrogen and phosphate. Simple control schemes are demonstrated for the pre-denitrification and the post precipitation system by means of full-scale plant experiments and model simulations.
Effect of lime stabilisation of enhanced biological phosphorus removal sludges on the phosphorus availability to plants
Authors: Seyhan D. , Erdincler A.
Published: May 2018

This study investigates the phosphorus (P) availability in lime stabilised biological phosphorus removal sludges. Lime-stabilised sludge amendments (LS), non-stabilised sludge amendments (S) and amendments with a chemical fertiliser (TSP) were compared through plant uptake of P and Olsen-extractable P for this purpose. In the first part of the study, pot experiments were performed, where a dewatered biological phosphorus removal sludge was applied to pots at increasing rates of P. A P-deficient, alkaline soil was used in the experiments and Lollium perenne was the testing plant. In the second part (incubation tests), the waste activated sludge from an Enhanced Biological Phosphorus Removal (EBPR) process was mixed with the same soil at a pre-determined P-based rate. The pot experiments showed that, the efficiency of the fertilising materials, based on the minimum P applied to reach the maximum yield, was in the following order: S∼LS>TSP. However, the P concentration in the plant tissue was in the order of TSP>S>LS for all P application rates. In the incubation tests, the EBPR sludge raised the soil P-level from the low range to the medium range. The P-availability in TSP decreased rapidly with time whereas that in S and LS remained almost constant.
Classification of lake sediments using a hydrocyclone
Authors: Park J.H. , Jo Y.M. , Oh J.M.
Published: May 2018

The present work is a preliminary experiment for hydrocyclones as a primary process in lake sediment thickening. A few cyclones based on the Rietema standard geometry were prepared, and sample particles were sediments from a local lake and waste coal fly ash for a reference test. As a result of the chemical analysis, more organic contaminants were found in smaller particles. The experimental tests showed that physical characteristics of particles, configuration of the cyclone and operation conditions could affect the separation efficiency.
A software monitor for intermittent bacteria contamination in urban rivers
Authors: Mietzel T. , Frehmann T. , Geiger W.F. , Schilling W.
Published: May 2018

Norwegian receiving waters are of such high water quality that authorities consider opening them for bathing. The leading parameter to monitor the quality of bathing waters is fecal coliform bacteria (FC). For this parameter no rapid detection method is available. The main objective of this case study was to find a way to quickly predict bacteria contamination by observing different online parameters such as flow, conductivity or spectral absorption coefficient (SAC). In this study historical data from 1994 to 2000 was analyzed, and over a period of five weeks water samples were taken and analyzed for bacteria. The analysis of the historical data revealed fundamental sampling problems, which made the data useless for the purpose of this study. The analysis of the data collected for this study showed that exceeding the bathing water standard for bacteria can be predicted by evaluating the SAC with an acceptable accuracy. Furthermore a simple river quality model was implemented, including bacteria as a load fraction. With the help of rain data and discharge predictions expected bacteria numbers exceeding the bathing water standard could also be forecast.
Integration of coliform decay within a CFD (computational fluid dynamic) model of a waste stabilisation pond
Authors: Shilton A. , Harrison J.
Published: May 2018

CFD mathematical modelling offers the potential to predict the actual flow pattern in a pond rather than generalising its mixing and mass transport as either an ideal flow reactor or, in the case of the non-ideal flow reactor, as a single dispersion number. However, perhaps the greatest benefit that CFD offers over the previous approaches is its ability to directly account for physical influences on the pond hydraulics such as the addition of baffles for example.

In addition to solving the equations of fluid flow, CFD modelling also allows incorporation of other equations. The next logical development is, therefore, the integration of a reaction model within its solution domain. This potential has been recognised by several researchers, but to date no such work has been published. The primary aim of this paper was to present a CFD model of a field pond that incorporates the first order decay equation for coliforms. Experimental monitoring of the field pond gave an average effluent concentration of 3,710 f.c./100 mL, while the CFD model predicted 4,600 f.c./100 mL. Considering the pond provides an order of magnitude decrease in faecal coliform concentration, the integrated CFD model has clearly predicted the treatment efficiency very well.

The secondary aim of this paper was to demonstrate the potential application of this technique. A typical pond was designed and modelled along with two variations incorporating two baffles and six baffles respectively. As is typically found in pond systems, the standard design suffered from severe short-circuiting with the model predicting a value of 6.2 × 106 f.c./100 mL at the outlet. The simulations of the baffled designs illustrate how treatment efficiency was improved by reducing the short-circuiting through the pond. The model predicted values of 6.0 × 103 f.c./100 mL for the 2-baffle design and 5.7 × 102 f.c./100 mL for the 6-baffle design.
Nutrient removal by the integrated use of high rate algal ponds and macrophyte systems in China
Authors: Chen P. , Zhou Q. , Paing J. , Le H. , Picot B.
Published: May 2018

High Rate Algal Ponds (HRAP) were operated at pilot scale to investigate the performance of HRAP under the temperate climate conditions of Shanghai, China. The results indicated that the HRAP gave good efficiency for nutrient removal, especially during summer. With a retention time of 4 or 8d according to the season, the annual average removal efficiencies for COD, NH4-N and PO4-P were 50%, 87% and 40%, respectively. The multi-factor linear models showed the relationships between nutrient removal efficiency and influencing factors. Using a macrophyte pond to separate algae from HRAP can achieve concentrations of COD, TP and TKN in the effluent at around 50 mg/L, 1.5 mg/L and 5 mg/L respectively.
Microbial quantification in activated sludge: the hits and misses
Authors: Hall S.J. , Keller J. , Blackall L.L.
Published: May 2018

Since the implementation of the activated sludge process for treating wastewater, there has been a reliance on chemical and physical parameters to monitor the system. However, in biological nutrient removal (BNR) processes, the microorganisms responsible for some of the transformations should be used to monitor the processes with the overall goal to achieve better treatment performance. The development of in situ identification and rapid quantification techniques for key microorganisms involved in BNR are required to achieve this goal. This study explored the quantification of Nitrospira, a key organism in the oxidation of nitrite to nitrate in BNR. Two molecular genetic microbial quantification techniques were evaluated: real-time polymerase chain reaction (PCR) and fluorescence in situ hybridisation (FISH) followed by digital image analysis. A correlation between the Nitrospira quantitative data and the nitrate production rate, determined in batch tests, was attempted. The disadvantages and advantages of both methods will be discussed.
Laser scanning detection of FISH-labelled Escherichia coli from water samples
Authors: Lepeuple A.-S. , Delabre K. , Gilouppe S. , Intertaglia L. , de Roubin M.-R.
Published: May 2018

The development of rapid and accurate methods for the detection and quantification of bacteria without cultivation is of increasing importance for water monitoring. The aim of this study was to develop a solid phase cytometry detection method for DVC-FISH labelled Escherichia coli cells. In order to allow automatic detection with ChemScan RDI, the fluorescein-tyramide was combined with an oligonucleotide probe directly labelled with horseradish peroxidase to increase the fluorescence intensity. The method developed was tested for the enumeration of pure cultures, for GAC-filtered and drinking water samples. The method, which appeared to be equivalent to the culture method, was less sensitive than the DVC-FISH method followed by microscopic analysis. Research is underway to further optimise the labelling conditions.