bluuebunny/crossref_metadata_2025 huggingface dataset:
Increase of purification capacity in small treatment units
Authors: Bischof Franz , Schulz Wolfgang , Teckenberg Ralph , Nitsch Peter
Published: May 2018

Especially in rural regions most of the costs for wastewater treatment arise from the sewerage system due to the long distances between the different smaller communities and the centralized treatment station. Meanwhile, there are a lot of different systems available for smaller communities like trickling filter systems or activated sludge treatment systems, respectivly. In general, these smaller treatment units can fulfill the demands for the purification efficiency given by the law. But especially in the range of about 200 to 1000 population equivalents there are hardly any systems known which can serve for a controlled denitrification process. Normally two single, locally distinguishable, basins are erected to allow for the biological demands of the denitrification process. This results in pumping an enormous amount of wastewater with dissolved nitrate within the treatment station, the so-called internal recirculation. In this paper, a novel reactor is described where the nitrification zone was set above the denitrification zone in one tank. Both regions are separated by an intermediate bottom. Stirring and aeration in the different zones are carried out simultaneously by two different-sized hyperboloid stirrers. The paper will give an introduction in the working principle of this novel system which was developed for community sizes lower than 1000 population equivalents. It can demonstrate the visualization of the flow field and the exchange of water between the two different zones.
The investigation of the advanced treatment of municipal wastewater by modular flotation-filtration systems and reuse for irrigation
Authors: Krofta Milos , Miskovic Dusan , Burgess David , Fahey Edward
Published: May 2018

The objective of this study was to provide clarified municipal wastewater effluent at the turbidity level of less than 2.0 NTU and reuse for landscape irrigation (golf course). For that purpose, during pilot -study first was used a combined flotation-filtration module-clarifier alone (Alternative I). A particularly designed configuration of the primary flotation unit and combined flotation-filtration clarifier, as a modular clarification system was used in the next step of the investigation (Alternative II). In addition, start up of the full scale plant was performed as well. In the first phase of this study, the impact of the type and concentration of coagulant and flocculant was tested. As a result, mechanisms of flocculation were proposed. Only under the moderate hydraulic loads (75.7-151.4 LPM) during pilot tests by Alternative I, was it possible to reach satisfactory turbidity reduction. By the Alternative II, the clarification performance was improved under the higher hydraulic load (302.8 LPM). The kinetics of the investigated flotation systems were assesed by empirical flotation models. Based on the pilot-study, Alternative II is recommended in order to reduce the high solids loadings under a higher hydraulic load, and it provided irrigation water at a required rate of 3785 m3/d during start up and optimization of the full scale plant.
Risk analysis of wastewater reclamation and reuse
Authors: Ganoulis Jacques , Papalopoulou Anastasia
Published: May 2018

Wastewater reclamation and reuse involve alternative technologies for sewage treatment (biological oxidation, nitrification-denitrification, use of lagoons and aquifer recharge), different states of nature (climatic conditions, type of soils, irrigated crops, irrigation systems, socio-economic environments) and various preferences or criteria (economic, environmental, aesthetics, etc.). Although tertiary treatment of municipal wastewater should be applied before any recycling of wastewater a risk still exists from enteric virus and toxic contaminations. To determine risks from wastewater reclamation and reuse, the engineering risk analysis is a very useful framework (Ganoulis, 1994). The various steps to be undertaken for a comprehensive application of risk analysis techniques to wastewater reclamation and reuse are summarized in this paper. These are (a) identification of hazards, (b) risk quantification, (c) consequences of risk and (d) risk management. The main objective of the analysis is to develop a Decision Support System (DSS) for managing the risks related to a particular application of wastewater reclamation and reuse.
Wastewater recycling and environmental constraints at a base metal mine and process facilities
Authors: O'Leary William
Published: May 2018

In temperate areas of abundant freshwater there is seldom an urgency to recycle. The statutory protection of inland waters for beneficial uses such as drinking, food processing and game fishing is requiring industries to choose recycling. A European success in this trend is a base metal mining/milling industry which, since 1977, is implementing hydraulic, hydrological, treatment and ecological studies with wastewaters and mine tailings. A model activity, located 50 km from Dublin is considered. Zinc and lead concentrates produced and exported to smelters ultimately yield approximately 194,000 t and 54,000 t of these respective metals (32 and 21 percent of European production). Water use as originally planned would have been approximately 6m3/t of ore milled. While ore milling increased by 25 percent to 8,500t/d in 1993, water use declined by 33 percent to 4m3/t. The components making up this reduction range from milling technology efficiency to greater recycling from the 165 ha tailings pond. Environmental standards, based on framework regulations originating in EU Directives, have been instrumental in achieving wastewater savings. A conclusion is the value of integrating water quantity, quality, recycling, storage, production and other factors early in project planning.
Electrochemical interactions of biofilms with metal surfaces
Authors: Lewandowski Zbigniew , Dickinson Wayne , Lee Whonchee
Published: May 2018

Two mechanisms of microbially influenced corrosion (MIC) are discussed and compared: corrosion modified by the presence of (1) sulfate-reducing bacteria (SRB) and (2) manganese-oxidizing bacteria (MOB). It is demonstrated that the nature of MIC in both cases depends on the nature of inorganic materials precipitated at the metal surface, iron sulfides and manganese oxides. Those materials are electrochemically active and, therefore, modify the electrochemical processes naturally occurring at the metal-solution interface. Some of these modifications may lead to accelerated corrosion.
Mass transfer mechanism in biofilms under oscillatory flow conditions
Authors: Nagaoka Hiroshi
Published: May 2018

The objective of this research is to investigate mass transfer mechanism in biofilms under oscillatory flow conditions, which provides valuable information for the understanding of self-purification by biofilms under oscillatory flow conditions like in coastal areas. A mathematical model was developed to describe substrate profiles in biofilms under oscillatory flow conditions, which suggested that substrate uptake rate by biofilms is proportional to the square root of the Reynolds number. A laboratory-scale channel with a wave generator was prepared, in which plastic plates were used as substratum for biofilms. Glucose was used as a substrate. Velocity and turbulence profiles near the biofilm were measured by a laser Doppler velocimeter. The cycle of the wave generator was changed and its short-term effect on the substrate uptake rate by the biofilm was measured. The substrate uptake rate decreased with the decrease of the Reynolds number of the wave motion according to a power law with a coefficient of 0.6, which suggests that substrate transport in biofilms under oscillatory flow conditions is carried out by turbulent diffusion caused by oscillatory flow motions over biofilms.
Photochemical decomposition of 2,4-dichlorophenoxy acetic acid (2,4-D) in aqueous solution. I. Kinetic study
Authors: Cabrera María I. , Martín Carlos A. , Alfano Orlando M. , Cassano Alberto E.
Published: May 2018

The intrinsic kinetics of the photochemical decomposition of 2,4-dichlorophenoxyacetic acid in aqueous solution has been studied using light of 253.7 nm. Experiments were carried out in a well stirred batch reactor irradiated from its bottom by means of a tubular lamp and a parabolic reflector. Results were analyzed in terms of a very simple kinetic expression. Absorbed radiation effects were duly quantified by means of a one-dimensional radiation field model. This approach incorporates a variable absorption coefficient that is a function of the 2,4-D conversion. The decomposition kinetics can be properly represented with a point valued equation of the following form: RD, λ = − ΦD,λ eλ(y).
Simulating the effect of blanket characteristics on the floc blanket clarification process
Authors: Head Richard , Hart Jem , Graham Nigel
Published: May 2018

Previous attempts at simulating the floc blanket clarification process have failed to predict adequately the performance of ‘real’ tanks on water treatment works over a range of treatment conditions. In this paper, a mathematical model of the floc blanket clarification process is presented. This model has been used to simulate the performance of a flat-bottomed clarifier operating on a full-scale water treatment works. The model predictions have been compared with data obtained from the treatment works, and the model has been shown to perform well. The model has then been used to simulate the effects of changes in the operating conditions of the clarifier on the concentration of the blanket in the clarifier and the quality of the treated water. The importance and potential uses of a model of the process at a treatment works are discussed.
Dynamics of oxidant addition as a parameter in the modelling of dye mineralization (Orange II) via advanced oxidation technologies
Authors: Bandara J. , Nadtochenko V. , Kiwi J. , Pulgarin C.
Published: May 2018

Light and dark processes involving Fenton reagent are effective in the degradation of Orange II solutions. The degradation time is shown to be strongly dependent on the initial pH of the solution used. Experimental results show that the mineralization rates for Orange II become significant only at pH <∼5. The H2O2 added and O2 evolved were monitored during the degradation cycles allowing optimization for the times for oxidant addition. About 88% dye mineralization in 40 minutes under light irradiation. A model for the degradation has been developed from the available kinetic rates for radical reactions. The model predicts an H2O2 consumption time of ∼100 seconds consistent with the experimental results obtained. A turnover number of 4.7 was estimated for light induced processes in the model system used. Near surface radical formation is shown to be important during the observed photocatalysis. No activation energy was detected during the mineralization suggesting a radical mechanism for this reaction.
Control of coagulation process by dual wavelength article analyzer
Authors: Tambo Norihito , Matsui Yoshihiko , Kurotani Ken-ichi , Kubota Masakazu , Akiyama Hirohide , Ohto Tokio , Zaitsu Yasushi , Itoh Haruo
Published: May 2018

A coagulation process for water purification plants mainly uses feedforward control based on raw water quality and empirical data and requires operator's help. We developed a new floc sensor for measuring floc size in a flush mixer to be used for floc control. A control system using model predictive control was developed on the floc size data. A series of experiments was performed to confirm controllability of settled water quality by controlling flush mixer floc size. An automatic control with feedback from the coagulation process was evaluated as practical and reliable. Finally this new control method was applied for actual plant and evaluated as practical.
ChemoxTM: advanced waste water treatment with the impinging zone reactor
Authors: Barratt Peter A. , Baumgartl Arne , Hannay Neil , Vetter Manfred , Xiong Feng
Published: May 2018

Air Products uses their CHEMOXTM process for advanced oxidation of a variety of waste waters, e.g. landfill leachate. The centrepiece of the CHEMOXTM process is the Impinging Zone Reactor (IZR) developed by the University of Clausthal. In the IZR waste water is intensively mixed with an ozone/oxygen mixture under atmospheric pressure and ambient temperature. Due to the excellent gas mass transfer performance of the IZR no expensive pressure vessels or gas compressors are required. Pilot plant trials were performed very successfully on a landfill leachate in Germany in 1995. Results from parallel operations with a commercial venturi/bubble column system and the CHEMOXTM process show a decrease in hydraulic retention time of 10.3 vs. 3.3 [h], a reduction of the O3/COD ratio of 3.2 vs 1.8 [kg/kg], and an energy consumption (without ozone generation) of 8.0 vs. 4.3 [kWh/kg ozone consumed] (meter reading) respectively. State-of-the-art, process controlled, mobile pilot plants provide the customer with the required information to accurately design and cost an effective ozone waste water treatment process.
Nutrient content of wetland plants in constructed wetlands receiving municipal effluent in tropical Australia
Authors: Greenway Margaret
Published: May 2018

Several pilot wetlands have been constructed in Queensland to treat municipal wastewater. The wetlands are in tropical, subtropical and arid geographical locations. Most wetlands are free water surface and contain a variety of macrophyte types and species. A total of 49 native and 11 exotic species of wetland plants have been identified. This paper examines tissue nutrient content in different species and plant components from 7 wetlands.

Most species translocated to the constructed wetlands flourished indicating their ability to tolerate nutrient enriched waters, and tended to have higher tissue nutrient concentrations than their controls in natural wetlands. Submerged and free floating species exhibited higher nutrient concentrations than floating leaved and emergent species. Maximum dry weight nutrient concentrations (mg.g−1) were recorded in duckweed 18 mgP.g−1; 58 mgN.g−1; Ceratophyllum 14 mgP.g−1, 35 mgN.g−1; Monochoria cyanea (a native relative of the water hyacinth) 13 mgP.g−1, 30 mgN.g−1; waterlilies: Nymphoides indica 16 mgP.g−1, 40 mgN.g−1; aquatic vines Ipomoea diamantinensis 10 mgP.g−1, 53 mgN.g−1, I. aquatica 9.5 mgP.g−1, 53 mgN.g−1; Ludwigia peploides 10 mgP.g−1, 52 mgN.g−1; and the water ferns Ceratopteris thalictroides 10 mgP.g−1, 31 mgN.g−1,Marsilea 10 mgP.g−1, 43 mgN.g−1. Emergent species with the highest nutrients (P or N) were Eleocharis sphacelata 9.4 mgP.g−1, 31.7 mgN.g−1, Baumea articulata 8.7 mgP.g−1, 24 mgN.g−1,Typha domingensis 7.2 mgP.g−1, 51.8 mgN.g−1 and Cyperus involucratus 7 mgP.g−1, 44.6 mgN.g−1.

Pooled data showed no significant difference between tissue nutrient content in plant components, though nitrogen was highest in the leaves and phosphorus highest in the roots of most species. There was some evidence of spatial variation in tissue nutrient content between different wetlands but it has not been possible to correlate this with nutrient loadings or removal efficiencies.
Terminology and methodology in modelling for water quality management - a discussion starter
Authors: Carstensen Jacob , Vanrolleghem Peter , Rauch Wolfgang , Reichert Peter
Published: May 2018

There is a widespread need for a common terminology in modelling for water quality management. This paper points out sources of confusion in the communication between researchers due to misuse of existing terminology or use of unclear terminology. The paper attempts to clarify the context of the most widely used terms for characterising models and within the process of model building. It is essential to the ever growing society of researchers within water quality management, that communication is eased by establishing a common terminology. This should not be done by giving broader definitions of the terms, but by stressing the use of a stringent terminology. Therefore, the goal of the paper is to advocate the use of such a well defined and clear terminology.
Sewer flow quality modelling
Authors: Heip Lennart , Van Assel Johan , Swartenbroekx Patrick
Published: May 2018

Within the framework of an EC-funded SPRINT-project, a sewer flow quality model of a typical rural Flemish catchment was set up. The applicability of such a model is demonstrated. Furthermore a methodology for model building, data collection and model calibration and verification is proposed. To this end an intensive 9 month measuring campaign was undertaken. The hydraulic behaviour of the sewer network was continuously monitored during those 9 months. During both dry weather flow (DWF) and wet weather flow (WWF) a number of sewage samples were taken and analysed for BOD, COD, TKN, TP and TSS. This resulted in 286 WWF and 269 DWF samples. The model was calibrated and verified with these data. Finally a software independent methodology for interpretation of the model results is proposed.
Modelling sewer emission using simulink
Authors: Ruan Mingchaun , Wiggers Jan B. M.
Published: May 2018

A dynamic programming package SIMULINK has been used to develop a conceptual emission model named SEWSIM for both event-based and continuous simulations of urban sewer systems. The model variables are mostly vectorized for simulation efficiency. The impervious catchment and the sewer network are schematised as two linear dynamic reservoirs. The physical processes that are conceptually modelled include solids buildup and washoff (catchment surface) and sediment erosion and deposition (sewer network). The conceptual model calibrated using measurements or simulation results of hydrodynamic models is able to predict the sewer emission using a long series of historical rainfall records.
The application of the activated sludge model No. 1 to a river environment
Authors: Maryns F. , Bauwens W.
Published: May 2018

The current tendency towards an integrated approach for water quality management gives rise to a demand for consistent methods for linking dynamic wastewater treatment models with river water quality models. Linking such models is difficult because of the mutual structural differences with regard to variable and parameter definitions as well as process descriptions. This paper proposes to use the same modelling approach for the simulation of activated sludge treatment and natural self-purification in rivers. Since the standard Activated Sludge Model No. 1 (ASM1) is found to be far more conceptual and consistent than traditional river water quality models, the suitability of the ASM1 modelling approach has been assessed. The traditional ASM1 matrix has been adapted and extended to a river environment and has subsequently served as the basis of an ASM1-type water quality model for the River Dender in Flanders. Sensitivity analyses on this model showed that the most sensitive parameters in the ASM1 formulation of biological decay are the ones determining hydrolysis. The model efficiently calculates BOD concentrations but the predicted DO concentrations are not very accurate, mainly because of the remaining uncertainty about the many ASM1-parameters in river conditions. This indicates the need for determining new typical value ranges for these parameters in a river environment.
Development of a new generation of reed-bed filters in France: first results
Authors: Boutin Catherine , Liénard Alain , Esser Dirk
Published: May 2018

Since 1992, Reed-Bed Filters (RBF) wastewater treatment plants have been built to meet the needs of 15 rural authorities and, on an experimental basis, 2 farms to treat milking parlour washwater using this method. This paper presents results obtained at a plant designed for 200 p.e. after 15 months of operation, organic and hydraulic loads being 67% and 115% of the nominal loads respectively. With an overall area of the order of 2.2 m2 per person equivalent, the plant produces an effluent which easily complies with the following water quality criteria : 90 mg l−1 COD, 30 mg l−1 TSS and almost 10 mg l−1 TKN. Phosphorus removal is normally very low. A farm-located experimental plant, receiving milking parlour washwater (COD between 700 and 1400 mg l−1), is providing promising results which will certainly be improved by extending the current RBF areas. RBFs are capable of directly treating raw sewage by applying procedures involving batch feeding and alternating several units operating in parallel; in this way aerobic conditions are maintained and physical surface clogging is controlled with the aid of rooted macrophytes. RBFs used for complementary treatment seem to accept continuously high hydraulic loads.
Role of adsorption in water environment processes
Authors: Suzuki Motoyuki
Published: May 2018

Aqueous phase adsorption isotherms and adsorption rates are reviewed. Among numbers of isotherm equations, a combination of adsorption potential and solvophobic concept was applicable to interpreting adsorption equilibrium data obtained for agrochemicals on activated carbon fiber. Intraparticle diffusion becomes the rate-limiting step in liquid phase adsorption on granular activated carbons. Correlation of diffusion coefficients based on surface diffusion mechanisms is introduced. As topics related to adsorption, sediment water partition, biological activated carbon, removal of volatile organics and nutrient removal are briefly reviewed.
Solid phase aerobic digestion of high strength organic wastewater using adsorbent polymer gel
Authors: Lim Byung-Ran , Huang Xia , Hu Hong-Ying , Fujie Koichi
Published: May 2018

A novel solid phase aerobic digestion process for high strength organic wastewaters using adsorbent polymer gel particles was developed. Characteristics of organic removal and water evaporation were investigated using laboratory scale experimental apparatus. It was found that the removal rate of organic pollutants adsorbed on polymer gels increased with the increase in organic concentration of wastewater and the temperature. The maximum rate of organic removal was as high as 10 kg-TOC.m−3.d−1 at about 50°C, but the elevated temperature beyond 50°C hindered the rate of organic removal and thus CO2 evolution rate. Mineralization of organic matters to CO2 was decreased as well. The mineralization of organic matters was in the range of 65% to 81%, corresponding to a temperature of 30 to 50°C. The increased temperature and air feed rate accelerated the water evaporation. Water evaporation rate was well estimated from the previously reported formulation and the mass transfer coefficient. Based upon the experimental results in the present study, a mathematical model was set up and used to simulate a optimal operating conditions to accelerate the mineralization of organic pollutants and to evaporate the wastewater.
Adsorption of viruses in water environment onto solid surfaces
Authors: Sakoda Akiyoshi , Sakai Yasuyuki , Hayakawa Kazuhiro , Suzuki Motoyuki
Published: May 2018

Recently the contamination of water environment involving rivers, lakes, the sources of drinking water, etc. by viruses has been paid attention to as a new threat. The behavior of the viruses found in water environment is not well understood so far. However, it is suspected in general that the viruses are adsorbed onto solid surfaces such as suspended solids and sediment and keep their activities for a long time. Most likely, it is true that the adsorption of the viruses onto solid surfaces is one of the major factors controlling their transport and survival in water environment. In this work, the adsorption equilibrium relations of model viruses in water environment and their activities on solid surfaces were investigated. The E. coli phage such as Qβ, fr, MS2 and T4 were employed for experiments as model viruses, and cellulose and its derivatives, kaolin, carbon black, etc. were chosen as model solid surfaces. All the adsorption isotherms of model viruses on model surfaces were successfully written as the linear expression by the Henry equation in the concentration range of 102-107 [PFU/ml]. The resultant Henry constants were correlated with the total acidity of the solid surfaces. Stability of the model viruses was completely different when they were adsorbed on the solid surfaces and when they were suspended in water. The viruses adsorbed on the solid surfaces were significantly stable compared with the suspended ones regardless of the surface properties. It is suggested that the shrinkage of the virus is one of the important survival factors and the adsorption onto solid surfaces enhances their activities.
Effects of activated carbon on treatment of photo-processing waste by sulfur-oxidizing bacteria
Authors: Lin Binle , Futono K. , Yokoi A. , Hosomi M. , Murakami A.
Published: May 2018

Establishing economic treatment technology for safe disposal of photo-processing waste (PW) has most recently become an urgent environmental concern. This paper describes a new biological treatment process for PW using sulfur-oxidizing bacteria (SOB) in conjunction with activated carbon (AC). Batch-type acclimation and adsorption experiments using SOB/PAC, SOB/PNAC, and SOB reactor type systems demonstrated that AC effectively adsorbs the toxic/refractory compounds which inhibit thiosulfate oxidization of SOB in PW. Thus, to further clarify the effect of AC, we performed a long-term (≈ 160 d) continuous-treatment experiment on 4- to 8-times dilution of PW using a SOB/GAC system which simulated a typical wastewater treatment system based on an aerobic activated sludge process that primarily uses acclimated SOB. The thiosulfate load and hydraulic retention time (HRT) were fixed during treatment such that they ranged from 0.8-3.7 kg S2O32-/l/d and 7.7-1.9 d, respectively. As expected, continuous treatment led to breakthrough of the adsorption effect of GAC. Renewing the GAC and continuing treatment for about 10 d demonstrated good treatment effectiveness.
Predicting the performance of fixed-bed granular activated carbon adsorbers
Authors: Hand D. W. , Crittenden J. C. , Hokanson D. R. , Bulloch J. L.
Published: May 2018

Granular Activated Carbon (GAC) adsorption is an effective treatment technology for the removal of Synthetic Organic Chemicals (SOCs) from drinking water supplies. This treatment process can be expensive if not properly designed. Application of mathematical models is an attractive method to evaluate the impact of process variables on process design and performance. In this study, a mathematical modeling methodology incorporating the pore and surface diffusion model (PSDM) is proposed for known mixtures in fixed-bed adsorbers. Thermodynamic correlations for estimation of equilibrium parameters and empirical correlations for estimation of mass transfer parameters are presented. The PSDM was successfully compared to a 6-component mixture for empty bed contact times (EBCTs) of 2.4, 4.9, and 9.56 minutes.
PTSA (pressure and thermal swing adsorption) method to remove trihalomethanes from drinking water
Authors: Nakano Shigekazu , Fukuhara Tomoko , Hiasa Masami
Published: May 2018

It has been widely recognized that trihalomethanes (THMs) in drinking water pose a risk to human health. THMs can be removed to a certain extent by the conventional point-of-use (POU) unit which is composed of activated carbon (AC) and microfilter. But it's life on THMs is relatively shorter than on residual chlorine or musty odor. To extent the life of AC adsorber, pressure and thermal swing adsorption (PTSA) was applied by preferential regeneration of chloroform. PTSA was effective to remove THMs, especially chloroform. Adsorption isotherms of chloroform at 25 and 70°C showed a remarkable difference so that thermal swing was considered effective. Chloroform was also desorbed by reducing pressure. By vacuum heating at 70°C, chloroform was almost desorbed from AC and reversible adsorption was considered possible. A prototype of POU unit with PTSA was proposed. Regeneration mode would consist of dewatering, vacuum heating and cooling (backwashing). The unit was maintained in bacteriostatic condition and could be used for a long time without changing an AC cartridge.
Effect of ozonation on preloading of background organic matter in granular activated carbon filters
Authors: Orlandini Ervin , Gebereselassie Tsegaye G. , Kruithof Joop C. , Schippers Jan C.
Published: May 2018

Background Organic Matter (BOM) preloading is adsorption of BOM onto Granular Activated Carbon (GAC) prior to the adsorption of target compounds, such as pesticides and other organic micropollutants (e.g. atrazine). BOM preloading is commonly found to speed up the breakthrough of target compounds during GAC filtration. Ozonation of GAC filter influent may be expected to lower BOM preloading, because it results in less adsorbable and more biodegradable BOM compounds. Short Fixed Bed (SFB) tests with virgin and preloaded GAC, performed within this study, confirmed that preloading of BOM present in pretreated river Rhine water speeds up the breakthrough of atrazine in GAC filters. BOM preloading was found to lower equilibrium adsorption capacity of GAC for atrazine, and to slow down both external and internal mass transfer rate of atrazine on/into GAC. Adsorption capacity of (crushed) GAC was determined from atrazine adsorption isotherms, while mass transfer rate coefficients were determined by fitting the Homogeneous Surface Diffusion model to the breakthrough of atrazine in the SFB tests. More pronounced BOM preloading was found in the GAC filter receiving non-ozonated influent than in its ozonated counterpart. Biodegradation of ozonated BOM was shown to lower BOM preloading in GAC filters.
Microbial degradation of petroleum hydrocarbons in estuarine sediment of Tama River in Tokyo urban aera
Authors: Yamane Akiko , Sakakibara Koji , Hosomi Masaaki , Murakami Akihiko
Published: May 2018

Aerobic and anaerobic biodegradation rates of petroleum hydrocarbons, i.e., hexadecane (HEX), phenanthrene (PHE), and anthracene (ANT), were determined in estuarine sediment of the Tama River in urban Tokyo, followed by estimating their respective degradation potential. While in a sediment slurry, the aerobic biodegradation rates of these petroleum hydrocarbons ranged from 40 to 70 μg·g−1 dry sediment· day−1. The anaerobic biodegradation rate of HEX was found to be 5 - 8 μg·g−1 dry sediment· day−1, whereas that of PHE and ANT could not be detected following a 2-month incubation. Aerobic degradation of HEX was not affected by coexistence with either PHE or ANT, nor by the salinity level. The number of HEX-, PHE-, or ANT-utilizing bacteria ranged from 5 - 10% of the total number of aerobic heterotrophic bacteria. We calculated their biodegradation potentials using the biomass of naturally existing petroleum hydrocarbon-utilizing bacteria present in the sampled sediment, with results for HEX, PHE, and ANT being 1.0 − 3.5, 4.2 × 10−2, and 1.2 × 10−2 − 9.4 × 10−1 μg·g−1 dry sediment· day−1, respectively. In the aerobic tidal sediment of the Tama River, the purification potentials of HEX, PHE, and ANT were assessed to be approximately equal to their accumulation potentials occurring at the normal water level.
Anaerobic treatment utilizing the function of activated carbon
Authors: Hanaki Keisuke , Saito Toshiaki , Matsuo Tomonori
Published: May 2018

Granular activated carbon (GAC) was used as supporting medium for bacteria in anaerobic process. The effectiveness of using GAC was examined with laboratory-scale experiments. Synthetic wastewater containing phenol was converted to methane more successfully in fluidized bed using GAC. Fluctuation in influent concentration of phenol was intentionally made to examine the dynamic response of the process. Temporary increase of influent phenol from 400 mg/l to 1000 mg/l, 2000 mg/l, and even to 4000 mg/l for 4 days did not affect the effluent phenol as much as methane production because adsorption and desorption capacity by GAC functioned as stabilizer of the fluctuation. The adsorbed phenol was then gradually degraded into methane. Higher biomass concentration and lower adsorbed phenol were observed in the top part of the fluidized bed than in the bottom part.
The degradation of highly concentrated organic wastewater by the sand layer method
Authors: Nakayama Masatomo , Enari Keijiro
Published: May 2018

The osmotic action of highly concentrated organic waste water through soil was investigated by a column experiment. In this experiment, 50cm high sand-filled columns were used. The experiment included to estimate the toxic effects of mercury on the biological degradation of highly concentrated organic waste water. By adding seed sludge to the top of the sand column, 90% of the TOC was removed. The TOC was removed within the first 20-30cm of the sand layer. Though the removal rate of T-N was low, the T-P removal rate was over 86%. The effect of mercury on the removal of TOC, T-N, and T-P was not marked in either case. Both the acidogenic activity and the methanogenic activity were measured, and they showed higher values in the upper layer compared with the lower layer. The values of these activities were low in the column experiment with mercury.
Evaluation of pollution reduction scenarios in a river basin: application of long term water quality simulations
Authors: Demuynck C. , Bauwens W. , De Pauw N. , Dobbelaere I. , Poelman E.
Published: May 2018

Because of stricter environmental regulations for surface water quality in Flanders, large efforts are made for the construction of sewers and water treatment plants. The present methodology to determine the necessary pollutant load reductions is based on the combination of simple mass balances, the 90-percentile discharge and neglects the self-purification capacity of the surface water. This method is very easy to apply but offers little guarantee that the goals set will be met. A sustainable river basin management requires a methodology to evaluate different options in pollution abatement strategies. Only by this, the available resources can be applied in the most advantageous, sustainable way.

In this paper, a methodology is proposed to evaluate water quality based on dynamic modelling. This methodology is illustrated by means of a case study on the river Dender. Continuous and simultaneous measurements uin 3 places along the river were used to calibrate and validate the model. Continuous simulations over a period of four years guarantee that, in contrast with traditional event type simulations, most discharge and hydrometeorologic conditions are taken into account. Attention was given to the occurrence of extreme events. These events will determine the global ecological condition of the river. CDF-curves (Concentrated-Duration-Frequency) make it possible to gain insight in the duration and the frequency of occurrence of events with inadmissible concentrations of dissolved oxygen and ammonia.

Besides simulations taking into account the present loads, different pollutant abatement strategies were analysed and compared. The applied methodology offers the possibility to evaluate the impact of different strategies and to locate present and future problems.
Retention and expression of recombinant plasmids in suspended and biofilm-bound bacteria degrading trichloroethene (TCE)
Authors: Bryers James D. , Sharp Robert R.
Published: May 2018

Exposure of plasmid recombinant microorganisms to an open environment, either inadvertently or intentionally, requires research into those fundamental processes that govern plasmid retention, transfer and expression. In the open environment, a majority of the microbial activity occurs associated with an interface, within thin biological layers consisting of cells and their insoluble extracellular polymer, layers known as biofilms. Current toxic wastewater or wastegas treatment reactors exploit bacterial biofilm systems for certain system operating advantages.

Using recombinant bacteria within a biofilm reactor to degrade xenobiotic wastes requires finding a suitable host to harbor and express the desired plasmid phenotype. Suitable host characteristics include: the ability to produce copious amounts of biofilm, resistance to waste-related injury and toxicity, and the ability to retain and express the desired plasmid during long term operation. This paper reports on a laboratory evaluation of factors governing plasmid retention and the expression of trichloroethene (TCE) degradative capacity in both suspended and biofilm cultures.
The role of a metabolic intermediate in the biodegradation of inhibitory substrates
Authors: Mungkarndee P. , Rao Bhamidimarri S. M. , Mawson A. J. , Chong R.
Published: May 2018

Biodegradation of the mixed inhibitory substrates, 2,4-dichlorophenoxyacetic acid (2,4-D) and para-chloro-ortho-cresol (PCOC) was studied in aerobic batch cultures. Each substrate added beyond certain concentrations inhibited the degradation of the other. This mutual inhibition was found to be enhanced by 2,4-dichlorophenol (2,4-DCP) which is an intermediate metabolic product of 2,4-D. When 2,4-DCP accumulated to approximatelY 40 mg/l degradation of all compounds in the mixed 2,4-D and PCOC substrate system was completely inhibited. The degradation of 2,4-D and PCOC individually was also found to be inhibited by elevated concentrations of 2,4-DCP added externally, while PCOC inhibited the utilization of the intermediate.
Biodegradation of aniline
Authors: Gheewala Shabbir H. , Annachhatre Ajit P.
Published: May 2018

Discharge of aniline to the environment must be controlled as aniline is toxic to aquatic life and also exerts additional oxygen demand due to nitrification reaction involved during its biodegradation. Organic carbonaceous removal by heterotrophs during aniline biodegradation releases NH4+ which is the substrate for autotrophic nitrifying bacteria. However, aniline is toxic to nitrifying bacteria and severely inhibits their activity. Accordingly, batch and continuous studies were conducted to assess the biodegradation of aniline and its inhibitory effect on nitrification. Synthetic wastewater was used as feed with aniline as sole carbon source for mixed microbial population.

Experiments were conducted at ambient temperatures of 30–32°C. An aerobic activated sludge Unit was operated at an HRT of about 13 hours and SRT of about 12 days. Biomass from aerobic activated sludge process treating domestic wastewater was acclimatized to synthetic wastewater Containing aniline. Removal efficiencies more than 95% were obtained for feed aniline concentrations upto 350 mg/l with insignificant inhibition of nitrification due to aniline. Ammonia oxidation rates of about 20–115 mgNH4N/l/d were observed.

Batch tests were carried out to test the inhibitory effects of high initial aniline concentrations on nitritication. Carbonaceous removal by heterotrophs proceeded rapidly within 4–6 hours with nitrification picking up as soon as aniline concentration dropped below 3–4 mg/l. For higher initial aniline concentration more than 250 mg/l, complete nitrification did not take place even after aniline Concentration dropped below 3–4 mg/l.
Aerated denitrification in full-scale activated sludge facilities
Authors: Goronszy Mervyn C. , Demoulin Gunnar , Newland Mark
Published: May 2018

The practice of manipulating activated sludge reaction environments to obtain maximum nitrogen removal has been optimized using cyclic activated sludge technology. In its simplest form, the sequences of fill aeration, settle and decant are consecutively and continuously operated in a compartmented variable volume reactor in which an initial reaction volume performs the function of a biological selector using biomass from a final reaction volume. The technology incorporates the principles of biological accumulation-regeneration processing in which a variable volume plug-flow reaction environment precedes a variable volume complete-mix reaction environment, both of which are typically in continuous fluid communication. This configuration and mode of operation allows removal performance in domestic wastewater treatment applications to meet less than 5 mgL−1 total nitrogen discharge limits. Low nitrogen concentrations are obtained using modified aeration sequences only in which the bulk phase sequenced dissolved oxygen concentration is typically less than 2 mgL−1 in a ramped profile beginning at zero. By that means a simultaneous or co-current nitrification-denitrification mechanism is obtained. Cycle manipulation required to maintain high nitrogen removal performance during less than design loadings is addressed. In-basin monitoring illustrates nitrogen removal performance obtained in domestic wastewater applications. This mode of operation is also important to the efficacy of biological phosphorus removal where available readily degradable soluble substrate is near to limiting.
Mechanical properties of waterwork sludges – shear strength
Authors: Wichmann Knut , Riehl Andreas
Published: May 2018

In order to ensure a regular and environmentally safe utilization and disposal of waterwork sludges especially the mechanical properties must be controlled. Monitoring of the mechanical properties is of great importance to almost all treatment, utilization and disposal operations. Depending on the raw water source and the treatment processes, different types of waterwork sludge can be described. The first step of this research project included the collection of data from literature reports, information about measuring methods on rheological and soil mechanical parameters and preliminary measurements on selected waterwork sludge samples. Measurement of vane shear strength is a method used in the field of waste disposal/landfill in Germany. Therefore this method was the main topic of the first investigations. Aims were to examine: 1. Influence of water contents and dewatering capacity on shear strength. 2. Correlation between laboratory and field measurement devices. Sludge samples from different waterworks were investigated with following devices: laboratory vane shear apparatus, pocket vane apparatus, pocket penetrometer and capillary suction time measuring.
Evaluation of thermal sludge solidification
Authors: Okuno Nagaharu , Uriu Masahiro , Horii Takao , Miyagawa Kazunori
Published: May 2018

In 1990, Shiga Prefectural Government started to operate a full scale sludge melting plan. The plant has the capacity for handling 40 ton dewatered sewage sludge cake per day. The slag has been reused for construction material, primarily as a substitute for coarse aggregate. Six years operation showed that dewatered cake could be reduced to 1/7 in weight and to 1/14 in volume by this melting and solidification process. The operation cost of the process was $125.4 for each ton of dewatered sewage sludge cake with 65% moisture content, which represented approximately 5–7% sewerage user's charge.
The behaviour of heavy metals and phosphorus in an ash melting process
Authors: Takaoka Masaki , Takeda Nobuo , Miura Satoshi
Published: May 2018

In this study, the bottom ash from wastewater treatment sludge was examined to investigate the behavior of heavy metals and phosphorus in the melting process by a lab-scale as well as a pilot-scale experiment. The lab-scale experiment was performed in air or argon at temperatures from 800 to 1500 °C using an electric furnace and crucibles. The proportions of heavy metals remaining in the slag after the melting were effected by the compositions of the ash, especially basicity (CaO/SiO2). The proportion of Cd, Pb, Zn and Cu in the residue increased with the elevated basicity. Phosphorus did not volatilized by the melting process, and remained as a stable form, Ca3(PO4)2 by conjugating with Ca. Pilot-scale tests were also performed using swirling type melting furnace at 1400°C. The volatile heavy metals, like Cd, Pb and As were found in the dust collected by ceramic filter, whereas Zn, Cr and Mn were combined into the slag by the melting process.
Anoxic treatment of low-strength wastewater by immobilized sludge
Authors: Zhou Gong-Ming , Fang Herbert H.P.
Published: May 2018

Low levels of phenol and m-cresol were effectively removed from wastewater under anoxic condition using immobilized sludge. A 138-day experiment was conducted using wastewater containing NO3−-N (22.3 mg·1−1), phenol (10 mg·1−1) and m-cresol (5 mg·1−1) at 30°C using sucrose (50 mg·1−1) as co-substrate in an upflow reactor packed with polyvinyl alcohol (PVA) beads entrapped with anoxic sludge and powdered activated carbon (PAC). Throughout the experiment, phenol and m-cresol in the effluent were below the detectable level of 1.0 mg·1−1 even when HRT (hydraulic retention time) was as low as 0.55 hour. The effluent quality in general decreased with HRT. At 5.9 hours of HRT, the reactor effluent contained 5.9 mg·1−1 of COD (chemical oxygen demand) and 1.3 mg·1−1 of NO3−-N; but at 0.55 hour, they were, 17.3 and 5.7 mg·1−1, respectively. The effluent COD was from the unidentified soluble microbial products. Methane was not produced after the startup, and all PVA beads were not disintegrated. Results of a batch test showed that organic substrate was preferably consumed by the denitrify bacteria in favor of methane-producing bacteria. Scanning electron micrographs showed that most bacteria were populated on the bead surface due to the availability of nitrate and substrate.
Membrane separation activated sludge for residual organic removal in oil wastewater
Authors: Seo G. T. , Lee T. S. , Moon B. H. , Choi K. S. , Lee H. D.
Published: May 2018

A hybrid membrane separation activated sludge process was investigated for treatment of residual organic matter in oily wastewater from an automobile engine manufacturing plant. A bench scale experiment was conducted to identify the biodegradability of the residual organic matter in activated sludge reactors at various HRT (equal to SRT), such as 5, 10, 20, 30 days. Removal efficiency of higher than 90% was obtained in terms of SCOD at more than 10 day HRT showing the possibility of biological treatment. Ultrafiltration test was also carried out for the residual organics using cross-flow membrane filtration system at transmembrane pressure (TMP) of 2.0 kg/cm2. The membrane used for this experiment was polysulfone hollow fiber membrane with 30,000 molecular weight cut off. The rejection rate was around 10% in terms of TCOD. This low rejection rate explains that the residual organics in the oil wastewater are soluble and their MWCO size distribution might be less than 30,000. However the combined membrane activated sludge process could maintain significantly high removal efficiency more than 95% for the residual organics in the oily wastewater. The enhancement in organic removal was estimated to be contributed to the increased biomass in the system resulting in the reduction of the organic loading.