bluuebunny/crossref_metadata_2025 huggingface dataset:
Activated sludge floc structure during aerobic digestion
Authors: Barbusinski K. , Koscielniak H.
Published: May 2018

Additional observations of the physical characteristics have been introduced to current monitoring of aerobic digestion of sludges coming from two wastewater treatment plants. New parameters have included determination of floc size and sludge specific surface. The internal floc structure was also examined with the use of microtome technique for slicing flocs into very thin sections. During aeration, considerable changes in floc dispersion occurred. Analysis of floc size distribution enables observation of regroupment of different sludge fractions and successive increase in frequency occurrence of the finest fractions, which usually hinder dewatering process. The decrease of average floc size has been accompanied by the increase in sludge specific surface. The time needed for “biological stabilization” has not occurred simultaneously with the time when physical parameters have been shaped in the best possible manner for further sludge treatment. The joint analysis of biochemical and physical properties including above mentioned parameters has enabled the assignment of aerobic digestion time more precisely. It has special meaning in pre-designing research as well as during the start-up of the aerobic digestion systems.
Alkaline and ultrasonic pretreatment of sludge before anaerobic digestion
Authors: Chiu Ying-Chih , Chang Cheng-Nan , Lin Jih-Gaw , Huang Shwu-Jiuan
Published: May 2018

Pretreatment of waste activated sludge (WAS) results in an improved efficiency of the subsequent anaerobic biotransformation of the organic matter to volatile fatty acids. The pretreatment process has been carried out using alkaline treatment, ultrasonic treatment (20 KHz, 120 W) and different combination of these two methods: alkaline followed by ultrasonic, as well as the combining method in which ultrasonic treatment is applied to WAS samples dosed with alkaline. The hydrolysis efficiency was evaluated based on the quantity of soluble COD (SCOD) and organic nitrogen in the pretreated WAS as well as the production of total volatile fatty acids (TVFA) in the following biochemical acid potential (BAP) test. For WAS samples with described pretreatments, the released SCOD varied from 36% to 89% of the total COD (TCOD) and soluble organic nitrogen from 34% to 42%. The TVFA/TCOD ratio of the raw WAS used in this study was less than 10%. For the alkaline pretreated WAS, the TVFA/TCOD ratio increased to 30%, and the following ultrasonic treatment enhanced the ratio 66%. Further, WAS samples pretreated using simultaneous ultrasound and alkaline treatment in which ultrasonic was applied to WAS samples dosed with 40 meq/L NaOH for 14.4 sec/mL could achieve a maximum TVFA/TCOD ratio of 84% in 21 hours. Therefore, the combination of simultaneous alkaline and ultrasound pretreatment is efficient in enhancing the production of volatile acids in WAS in order to achieve recovery of volatile fatty acids from the WAS.
Production of glass ceramics from sewage sludge
Authors: Endo Hisashi , Nagayoshi Yoshikazu , Suzuki Kenji
Published: May 2018

Environmental problems are a worldwide concern. So recycling with a zero-emission objective is being pursued.

For this purpose, a melting process whereby sludge was converted into slag has been developed and commercialized. However, as the glass material of conventional slag is inferior compared to natural stone, the use of slag as a substitute material has been limited. Therefore, glass ceramics technology was studied to produce crystallized glass from sewage sludge. The technology was researched and developed jointly with the Tokyo Metropolitan Government in pursuing the basic study and pilot plant studied from 1991 to 1995. As a result, we have successfully commercialized this technology to convert sewage sludge into a resource as stone-like products, followed successfully by a long pilot operation. Now the commercialized plant of 150 ton-cake/day was installed and has been producing stone products from sewage sludge since 1996. In this paper, we report the results of the latest pilot plant test, and the application study of stone products for recycling use as well. For long decades, we obtain building materials from mountains and forests then built up metropolis. Then the metropolis exhaust waste and surrounding environment is polluted.

We are convinced that this technology may contribute to prevent such environmentally unbalanced cycle.
Characteristics of heavy metal release from incinerated ash, melted slag and their re-products
Authors: Ozaki Masa-aki , Watanabe Haruki , Wiebusch Bernd
Published: May 2018

Several leaching tests were conducted for sewage sludge and their re-products to investigate the characteristics of heavy metal release. Regarding incinerated ash, leaching tests indicated that the concentrations of Se and As in leachate were relatively higher than those of other heavy metals. The ratio of As extracted into leachate varied according to the leaching test method. The lower the pH value of leachate after the leaching test, the higher the concentration of As observed. The data using the Holland method had the highest value, and 19.7–46.9% of As was extracted into leachate. If the ratio of concentration in leachate to content (L/C) by the Holland method is 1.00, that of other methods was 0.20–0.43. Regarding melted slag, leaching tests indicated that the heavy metal concentrations in leachate were very low. Regarding re-products, leaching tests indicated that the heavy metal concentrations in leachate were much lower than those of incinerated ash and melted slag. The diameter effect of crushed sample was investigated by the Holland method. 0.3–0.7% of As was extracted from the crushed samples having diameter 20–50 mm and 0.9–2.6% of As was extracted from the samples having diameter less than 5 mm.
Effect of ozonation for treatment of micropollutants present in drinking water source
Authors: Kang Joon-Wun , Park Hoon-Soo , Wang Rong-Yan , Koga Minoru , Kadokami Kiwao , Kim Hyeon-Yeoul , Lee Eung-Taek , Oh Sung-Min
Published: May 2018

Pilot tests were performed to investigate the effectiveness of ozonation for the treatment of drinking water. Prior to the experiment, four regional target water were analyzed for determining target compounds. Various organics including pesticides were identified and present also in the conventionally treated tap water. The contamination of pesticides in most raw water was severe and ozonation was found to be effective to remove pesticides significantly. Other organic species were removed effectively as the order of aromatic amines, nitro compounds, ketones and ethers. On the whole, volatile organics were removed effectively than DOC, CH2Cl2 extractable organics. Accompanying with the increasement of AOC, aldehydes have increased after ozonation and reduced by post-GAC. Also, bromate was produced after ozonation and it was validated to suppress the production of bromate on the presence of ammonia and DOC.
Study on secondary reaction and fate of hazardous chemicals by oxidants
Authors: Kim S. J. , Oh K. H. , Lee S. H. , Choi S. S. , Lee K. C.
Published: May 2018

The water treatment procedure can lead to the formation of by-products, when the drinking water source is contaminated with trace amounts of organic matter. In this study, the disinfection by-products (DBPs) of trace organic compounds were identified to provide the knowledge on the possible DBPs of the contaminated water during the general or emergent water treatment procedure. Chlorination or ozonation was performed in the laboratory scale under the conditions for the drinking water treatments, and the DBPs of 16 VOCs and 4 phenols were screened using gas chromatography/mass spectrometry (GC/MS). By the chlorination, dichlorobenzene was produced from benzene, ethylbenzene and styrene. 1,2-dichloroethane, 1,2-dichloropropane and phenol produced 1,1,1-trichloroethane, chloroform and chlorophenol, respectively. By the ozonation, bromoform changed to dibromomethane and styrene produced benzaldehyde. Finally, the water treatment method of each classified contaminant group was suggested for the emergency control of contamination.
Membrane operations
Authors: Bilstad Torleiv
Published: May 2018

The success of any industrial pretreatment program is dependent on correct choice of technology and management. The rapid growth in the industrial sector has increased the mass of toxic and hazardous pollutants to the municipal wastewater treatment works. This may again inhibit the conventional biological treatment processes. Membrane separation is in this context a physical pretreatment process which splits the flow of water in two; a less toxic permeate and a more concentrated retentate. Typically, the volume reduction is one order of magnitude from the feedflow to the retentate.

Engineering contractors in general do not possess proper knowledge of membrane technology to convincingly include membranes as a viable process option in design of pre-treatment systems. Attractive features of membranes are low weight and space requirements without use of chemicals. Moreover, the equipment is modular and can be scaled up or operated at partial capacity.

The paper documents examples of accumulated field experiences with the intention to prove that membrane separation is a mature technology for the industry to utilize and for the engineering contractor to master. Also, the paper conveys information pertinent to advances in membrane separation to better enable academia to adjust curricula to meet industrial demands for separation engineers. The challenge is to pick the right membrane for a specific wastewater and couple the membrane to compatable auxiliary equipment such as pumps, pipes, valves and meters.
Regulating industrial wastewater discharged to public wastewater treatment plants - a conceptual approach
Authors: Grüttner H.
Published: May 2018

The paper describes some of the basic principles behind the DEPA Guidelines for discharge of industrial wastewater to public sewers set in operation in 1995 and evaluates some of the experiences with the implementation.

It is described how such guidelines support the approach of pollution prevention and the implementation of cleaner technology by putting a stress on the industry. Further an approach for the balance between environmental and technological considerations is introduced.

The need for easily understandable environmental priorities is stressed and a concept for this is presented along with its combination with available technology. Finally expression of the environmental requirements are discussed in relation to environmental and technological considerations.
Degradation of triethylene glycol dimethyl ether by ozonation combined with UV irradiation or hydrogen peroxide addition
Authors: Beschkov V. , Bardarska G. , Gulyas H. , Sekoulov I.
Published: May 2018

Ozonation of pure aqueous solutions of the polar aliphatic refractory triethylene glycol dimethyl ether (TEGDME) which is a typical representative of organic solutes of oil reclaiming wastewaters does not lead to effective mineralization unless high ozone doses are applied. Small doses of UV irradiation do not markedly increase TEGDME mineralization by ozonation, but transformation to more oxidized products (mainly carboxylic acids containing methoxy and/or ethoxy groups) which are biodegradable to a higher degree than TEGDME. Addition of high concentrations of hydrogen peroxide during ozonation results in efficient increase of TEGDME mineralization, however. The presence of humic acids - which is a consequence of biological treatment of wastewaters containing biodegradable organic constituents - has a beneficial effect on transformation of TEGDME during ozonation or ozone/UV treatment because hydrogen peroxide is formed during ozonation of humic acid C-C double bonds.
Aerobic and anaerobic biodegradation of nitroglycerin in batch and packed bed bioreactors
Authors: Bhaumik S. , Christodoulatos C. , Korfiatis G. P. , Brodman B. W.
Published: May 2018

Glycerol trinitrate (GTN) is a contaminant commonly found in the waste streams of munitions manufacturing and pharmaceutical plants. It is a highly toxic substance harmful to humans and other living organisms. In this study, the bioconversion of GTN was examined under aerobic conditions using mixed bacterial cultures and Phanerochaete chrysosporium, and under strict anaerobiosis using anaerobic digester sludge. Batch reactor experiments indicated that activated sludge, P. chrysosporium, and anaerobic digester sludge can completely denitrate GTN via a mechanism which forms isomeric glycerol dinitrate (GDN), glycerol mononitrate (GMN) and a utilizable carbon source, most likely glycerol. The rate of bioconversion in the aerobic and the anaerobic systems was dependent upon the concentration of cosubstrate. Continuous flow experiments in immobilized bed reactors indicated that anaerobic degradation of GTN can achieve high destruction efficiencies of the parent compound (99.9%) and the intermediate metabolic nitrate ester compounds (GDN, GMN) at relatively low cosubstrate requirements compared to the aerobic reactors.
Treatment of chlorinated organics in bleached kraft mill effluents by activated sludge process
Authors: Ataberk Selale , Gökçay Celal F.
Published: May 2018

Combined effluents from a bleached Kraft pulp mill using annual plants were treated in a lab-scale activated sludge (AS) system. The effects of operating solids retention time (SRT) and concentration of additional carbon source on AOX removal were investigated. Higher AOX removals (30%) were observed with long SRTs, 99% of which was pure metabolization. As SRT was decreased AOX removal efficiency also decreased (4%) and principal AOX removal mechanism changed to adsorption onto wasted biomass. The AOX removal efficiency was lower (10%) on a 20% decrease in the supplemental carbon source, with no apparent effect on the removal mechanism.
Treatment of integrated newsprint mill wastewater in moving bed biofilm reactors
Authors: Broch-Due A. , Andersen R. , Opheim B.
Published: May 2018

Wastewaters from three integrated newsprint mills have been treated in a pilot plant Moving Bed Biofilm Reactor (MBBR). In the MBBR the biomass adheres to small plastic elements which move freely along with the water in the reactor. A reduction of 65-75% for COD and 85-95% for BOD was obtained at HRT of 4-5 hours. By prolonging the HRT the removal efficiencies of COD and BOD increased to about 80% and 96%, respectively. With a subsequent chemical precipitation a removal efficiency of COD up to 95% was achieved. The amount of chemicals needed for precipitation of the biologically treated wastewater was only a quarter to a third of that needed for chemical treatment of the untreated wastewater. The results showed the MBBR process to be competitive with conventional biological treatment systems and that treatment objectives can be met at short HRTs.
Pretreatment of tannery wastewaters by an ion exchange process for Cr(III) removal and recovery
Authors: Tiravanti G. , Petruzzelli D. , Passino R.
Published: May 2018

Conventional treatment of tannery wastewaters includes the physico-chemical treatment in order to precipitate metals (mostly Cr(III). The landfilling disposal of mixed physico-chemical and biological tannery sludges is an economical and environmental problem, due to the saturation of possible sites.

A new process, namely, IERECHROM® (Ion Exchange REcovery of CHROMium), has been developed for removal, recovery and reuse of Cr(III) ionic complex from segregated tannery wastewaters. The process is based on the use of a weak electrolyte macroporous carboxylate resin, retaining the metal of reference together with other trace metals, including aluminum and iron.

A 10 m3/d fully automated pilot plant was assembled and a demonstration campaign was carried out at a medium size Italian tannery by using the IERECHROM process. The adoption of the IERECHROM process simplified the tannery wastewater treatment lay-out as the physico-chemical treatment was not necessary. A considerable decrease in the use of chemical compounds, a sludge production reduced by 80% with respect to the traditional treatment, and lower costs for sludge treatment and disposal were demonstrated.
Combined oxidative and biological treatment for separated streams of tannery wastewater
Authors: Jochimsen Jan C. , Schenk Harm , Jekel Martin R. , Hegemann Werner
Published: May 2018

The biological treatment of the tannery wastewater substreams beamhouse (BH, pre-tanning steps) and tan-yard wastewater (TY, tanning, & wet-finishing process steps) and the application of an oxidative treatment by ozone, followed by a second aerobic treatment are investigated.

Due to the extremely changing quality of the raw wastewater, esp. TY, the biological pre-treatment could not be stabilized all the time and nitrification was sometimes inhibited. Oxidative treatment distinctly improved the aerobic biodegradability of refractory organic compounds and it was found to be optimal in the range of a specific ozone consumption of about 2 g O3/g DOC0 for both batch experiments and continuous operating conditions.

Moreover, full nitrification could be established during the subsequent aerobic degradation and the remaining ammonia was completely removed. Summing up, it can be stated that the combined oxidative and biological treatment of BH and TY was effective and ensures the meeting of given COD and ammonia-limits for the direct discharge of this special industrial wastewater into rivers.
Anaerobic pre-treatment of petrochemical effluents: terephthalic acid wastewater
Authors: Kleerebezem Robbert , Mortier Joost , Hulshoff Pol Look W. , Lettinga Gatze
Published: May 2018

During petrochemical production of purified terephthalic acid (PTA, 1,4-benzene dicarboxylic acid), a large quantity of concentrated effluent is produced. Main polluting compounds in this wastewater are terephthalic acid, acetic acid and benzoic acid in decreasing order of concentration. Acetic acid and benzoic acid are known to be rapidly degraded in high rate anaerobic treatment systems, such as Upflow Anaerobic Sludge Bed (UASB) reactors. Concerning the kinetics of anaerobic mineralization of terephthalic acid, however, no information is available in literuature. Therefore our work focused on the anaerobic degradation of neutralized terephthalic acid (disodium terephthalate) in laboratory scale UASB-reactors and batch reactors. It was found that high rate anaerobic treatment of terephthalate was difficult to obtain due to the low growth rate (μ ≈ 0.04 day−1) of the terephthalate mineralizing mixed culture. The maximum removal capacity of a lab-scale UASB-reactor was found to be 3.9 g COD.1−1 .day−1 at a loading rate of 4.5 g COD.1−1 .day−1 and a hydraulic retention time of 24 hours. Terephthalate was used as sole carbon source during these experiments. Addition of small amounts of sucrose (co-substrate) to the influent, as a source of reducing equivalents, was found to have a negative influence on the anaerobic degradation of terephthalate. Also benzoate was found to inhibit the mineralization of terephthalate. Batch-toxicity experiments showed that terephthalate is not toxic to any of the species involved in its mineralization. Based on these observations, a staged anaerobic reactor system is suggested for the anaerobic pre-treatment of PTA-wastewater.
Process parameter development for ozonation of kraft pulp mill effluents
Authors: Hongde Zhou , Smith Daniel W.
Published: May 2018

Wastewaters discharged from the aerated lagoon basin of a kraft pulp mill were ozonated using both bench scale and pilot scale fine bubble contactors. Effects of contactor scaling-up on ozonation effectiveness were examined by comparing the removal efficiencies of color, AOX (adsorbable organic halides) and other wastewater characteristics. The absorption efficiency of ozone was determined by monitoring the exit off-gas ozone over a wide range of operating conditions. Overall mass transfer coefficient (kLa) and its enhancement factor due to the occurrence of rapid ozone decay reactions (E) were then quantified by applying the two-film theory to an irreversible gas-liquid reaction. Results showed that ozone was very effective in oxidizing color and AOX-causing compounds. The effectiveness could be simply related to the amount of utilized ozone alone, regardless of the variations in gas flowrate, inlet ozone concentration, and contactor configurations. In contrast, the ozone absorption was affected by both operating conditions and wastewater characteristics. Its rate might be enhanced substantially due to the presence of ozone decay reactions, particularly in the cases of occurring rapid ozone decay reactions. Accordingly, a relationship was developed to describe the dynamic changes of EkLa values versus the utilized ozone.
Genetic toxicity of pulp mill effluent on juvenile chinook salmon (Onchorhynchus tshawytscha) using flow cytometry
Authors: Easton M. D. L. , Kruzynski G. M. , Solar I. I. , Dye H. M.
Published: May 2018

On-site bioassays were conducted at the furthest upstream pulp mill on the Fraser River in British Columbia. Uncontaminated river water was used to dilute treated effluent as discharged from the final diffuser pond. A single cohort of juvenile (8-10gm) chinook salmon (Oncorhynchus tshawytscha) was divided into an hypoxic group receiving 65% oxygen saturated water and a normoxic group receiving ambient 88% oxygen saturated water. Both groups were exposed over a period of 30 days to effluent concentrations of 2%, 4%, 8%, and 16%, while the controls received uncontaminated river water. This range of concentrations spanned those encountered by wild juvenile salmon overwintering in the upper Fraser River mainstem. The blood when analyzed by flow cytometry showed significant concentration-dependent clastogenic damage in both the normoxic and hypoxic groups starting at the 4% concentration. A concentration-response curve was determined from the hypoxic data set. Genetic implications of mutagenic damage to natural populations of chinook salmon are discussed along with the utility of the flow cytometer in detecting genotoxic damage.
Designing environmental monitoring for pulp mills in Australia
Authors: Keough M. J. , Mapstone B. D.
Published: May 2018

We describe an approach to environmental monitoring that has been developed to deal with future pulp mills in Australia. We propose decision criteria that balance the chance of missing impacts and the chance of falsely accusing a proponent of environmental damage. Rather than focusing on either Type I or Type II statistical errors, we fix the ratio of the two error rates according to perceived costs of making each error. As monitoring is scaled up or down, risks of both errors rise and fall proportionately, in contrast to more traditional approaches, in which one error rate is fixed. We describe the steps necessary to implement a monitoring program using these criteria. Our emphasis is on guidelines that allow the flexibility to deal with monitoring a range of point source discharges in coastal environments that vary widely.
Anaerobic/aerobic biodegradation of pentachlorophenol using GAC fluidized bed reactors: optimization of the empty bed contact time
Authors: Wilson Gregory J. , Khodadoust Amid P. , Suidan Makram T. , Brenner Richard C.
Published: May 2018

An integrated reactor system has been developed to remediate pentachlorophenol (PCP) containing wastes using sequential anaerobic and aerobic biodegradation. Anaerobically, PCP was degraded to predominately equimolar concentrations (>99%) of monochlorophenol (MCP) in two GAC fluidized bed reactors at Empty Bed Contact Times (EBCTs) ranging from 18.6 to 1.15 hours. However, at lower EBCTs, MCP concentrations decreased to less than 10% of the influent PCP concentration suggesting mineralization. The optimal EBCT was determined to be 2.3 hours based on PCP conversion to MCPs and stable reactor operation. Decreasing the EBCT fourfold did not inhibit degradation of PCP and its intermediates, thus allowing removal of PCP at much lower detention time and resulting in a significant cost advantage.

Analytical grade PCP was fed via syringe pumps into two fluidized bed reactors at influent concentrations of 100 mg/l and 200 mg/l, respectively. Acting as the primary substrate, ethanol was also fed into the reactors at concentrations of 697 and 1388 mg/l. Effluent PCP and chlorinated phenolic compounds were analyzed weekly to evaluate reactor performance. Biodegradation pathways were also identified. 3-chlorophenol (CP) was the predominant MCP and varied simultaneously with 3,5-dichlorophenol (DCP) concentrations. Likewise, 4-CP concentrations varied simultaneously with 3,4-DCP concentrations.

A second stage aerobic GAC fluidized bed reactor was added after the anaerobic reactor to completely mineralize the remaining MCP and phenols. Data show no presence of phenol and MCP in the effluent or on the GAC. Overall, the chemical oxygen demand (COD) fed to the system was reduced from 75 g/d in the influent to less than 1.5 g/d in the effluent.
The bacterial numeration and an observation of a new syntrophic association for granular sludge
Authors: Jianrong Zhu , Jicui Hu , Xiasheng Gu
Published: May 2018

The bacterial numeration and microbial observation were made on granular sludge from laboratory single and two-phase UASB reactors. It was shown that the fermentative bacteria (group I), H2-producing acetogenic bacteria (group II) and methanogenic bacteria (group III) of granular sludge in single UASB reactor were 9.3 × 108−4.3 × 109, 4.3 × 107−4.3 × 108, 2.0−4.3 × 108, respectively, during the granulation process. The sludge of methanogenic reactor exhibited the similar results. That indicates there is no big difference between suspended and granular sludge, and bacterial population for three groups of anaerobic bacteria are similar. The formation of granular sludge depends mainly on the organization and arrangement of bacteria. An observation of granular sludge using electron microscope revealed that the fermentative bacteria and hydrogenotrophic methanogens existed on outer surface of granules, and aceticlastic methanogens and H2-producing acetogenic bacteria occupied the inner layer. A new syntrophic association between Methanosaeta sp. and Syntrophomonas sp. (even plus Methanobrevibacter sp.) was observed. Because Methanosaeta can effectively convert the acetate (the end product of propionate and butyrate) to methane, such a new syntrophic association is supposed to support the degradation of short fatty acids and high methanogenic activity of granular sludge. Based on structural pattern, a hypothesis on mechanism of granulation called “crystallized nuclei formation” is proposed.
Phase separation during anaerobic fermentation of solid substrates in an innovative plug-flow reactor
Authors: Liu Tuanchi , Ghosh Sambhunath
Published: May 2018

Separation of the liquefaction-acidification and gasification phases of anaerobic digestion was studied in a simple, plug-flow reactor (PFR) charged with 3 to 10 wt% solids-content feed slurries. The unmixed PFR had zigzagging parallel channels with floors sloping towards the outlet. Steady-state runs were conducted at hydraulic retention times of 32 to 13 days and organic loading rates (OLRs) of 0.84 to 6.84 kg-VS/m3-d. Phase separation was first observed when the OLR was 2.05 kg-VS/m3-d. Longitudinal pH and volatile fatty acid (VFA) profiles at this OLR showed a lowest pH of 6.10 and a highest VFA accumulation of 1500 mg/l. The acidogenic phase predominated within the first 50 cm from the inlet, and the methanogenic phase prevailed in the remainder of the PFR. At an OLR of 6.84 kg-VS/m3-d the pH dropped to 4.4, and the VFA accumulated to 9600 mg/l with the acidogenic phase extending to 83 cm from the PFR inlet. Unlike a CSTR digester, the PFR always recovered from the initial sour digestion and afforded high VS reductions of 78 to 63% corresponding to methane yields of 0.36 to 0.28 m3/kg-VS added.
The effect of extreme temperatures (70–80°C) on the effluent quality and sludge characteristics of UASB reactors
Authors: Lepistö Raghida , Rintala Jukka
Published: May 2018

The study focused on the effluent quality and sludge characteristics during the start-up and operation of extreme thermophilic (70 to 80°C) upflow anaerobic sludge bed (UASB) reactors, inoculated with mesophilic and thermophilic granular sludge and fed with acetate, volatile fatty acids (VFA), and thermomechanical pulping (TMP) whitewater. Low effluent quality and long start-up periods were observed during the start-up of the 70 to 76°C, VFA-fed UASB reactors inoculated with mesophilic granulae, while better effluent quality and considerably shorter start-up periods were observed when thermophilic (55/70°C) inocula were used. With VFA feed, a significant amount of acetate was removed at 70°C and even at 80°C, while propionate removal was negligible. With TMP whitewater feed, low VFA effluent concentration was obtained at 70°C. The volatile solids (VS) and the VS/total solids (TS) content of the sludge decreased significantly during the first 2–3 months of operation when mesophilic inocula were used. The initial specific methanogenic activity (ISMA) of the extreme thermophilic sludge decreased with increasing temperature and was slightly higher on glucose than on acetate. At 70 to 80°C, various rod-like bacteria were dispersed through the granulae in either individual or in low density micro colonies surrounded with a varying degree of precipitates.
Influent calcium removal by crystallization reusing anaerobic effluent alkalinity
Authors: van Langerak E. P. A. , Hamelers H. V. M. , Lettinga G.
Published: May 2018

Waste waters from the waste paper industry and landfill leachates contain high calcium concentrations. Treatment of those waste waters in an anaerobic system will lead to extensive precipitation of calcium carbonates. Problems due to accumulation of calcium carbonate in anaerobic reactors can be avoided by applying a crystallization reactor to remove calcium from the influent. This solution, however, is expensive due to the need to dose alkalinity. In this paper, the possibility of reusing the produced alkalinity by recirculating anaerobic effluent was investigated. Calculations and experiments were carried out to investigate to what extent calcium could be removed from the influent. Experiments were carried out in a 4.5 1 UASB reactor and a 0.8 1 crystallization reactor, seeded with sand. The influent contained up to 1800 mg.l−1 calcium and the substrate was acetic acid. Removal of calcium from the influent could be successfully accomplished. Recirculation of the anaerobic effluent supplied sufficient bicarbonate alkalinity for crystallization. Consequently, no extra chemicals (i.e. Na2CO3 and/or NaOH) were needed. A chemical equilibrium model, with adapted pseudo solubility products, is a very useful tool to determine the proper recycle ratio of effluent for optimal performance.
Anaerobic decomposition of organic carbon in paddy soil in relation to methane emission to the atmosphere
Authors: Inubushi Kazuyuki , Hori Kenzo , Matsumoto Satoshi , Wada Hidenori
Published: May 2018

Paddy fields are regarded as one of the most important sources of methane emission which is enhancing global warming. To estimate decomposition processes of organic carbon in paddy soil quantitatively, firstly, kinetics of anaerobic decomposition of soil organic carbon (C) were investigated in laboratory experiments with or without organic amendments at 5, 20, 30 and 40 °C for 84 days of incubation. Produced CH4, CO2 and accumulated fatty acids were measured periodically, and first-order kinetics models were applied to the amount of decomposed C. Two components' model fitted decomposition pattern for unamended soil, but not for glucose or alanine-amended soils. To compare the parameters included in the model with those of adjacent upland soil, paddy soil contained smaller but faster components of decomposable organic matter. Secondly, methane emission from paddy soil was examined in paddy soil microcosms to find the possible mitigation options for reduction of the emission. Ammonium sulfate and potassium sulfate (S) were applied to compare with ammonium chloride and potassium chloride (C). Additionally ferrous oxide (F) was also applied to half sets of each treatment to make totally four treatments. Methane emission rate was significantly reduced by addition of S, much more effective than addition of F. Gas formation in the soil corresponded with the amendments, and the ratio of produced CH4 to CO2 decreased by addition of S at peak time of methane emission.
The role of process configuration in the performance of anaerobic systems
Authors: Speece Richard E. , Duran Metin , Demirer Goksel , Zhang Henry , DiStefano Thomas
Published: May 2018

Many studies on biological systems have been conducted. These studies have demonstrated that subtle differences in process configuration such as phasing, staging, biofilms, granules, gas phase management, and combinations thereof can profoundly impact anaerobic process performance. Possible reasons for these differences as well as examples of various studies are presented.
Random characteristics of runoff coefficient in urban catchments
Authors: Becciu G. , Paoletti A.
Published: May 2018

In the paper an analysis of hydrological losses, observed during storm events recorded in experimental urban catchments, is presented. Random nature of runoff coefficient and its effects on peak discharge estimation are discussed. Simple relationships for estimation of main moments of runoff coefficient are presented.
Fluxes of nutrients in urban drainage systems: assessment of sources, pathways and treatment techniques
Authors: Herrmann Thilo , Klaus Uwe
Published: May 2018

On the basis of a literature study the sources and pathways of water, nitrogen and phosphor are identified. The mean annual load is related to the number of inhabitants and given in mass or volume per capita and year. The toilets are identified as predominant sources of N and P. 60% of nitrogen and 80% of phosphor are concentrated in 2 liters or 1% of the water flow. The drainage system is a diluting system. The introduction of waste water separation at the source is recognized to be most effective to improve the surface waters quality. Innovative source separating technologies are recommended for modern drainages' future.
Urban runoff impacts on particulate metal and hydrocarbon concentrations in river seine: suspended solid and sediment transport
Authors: Estèbe Alexandrine , Boudries Hacène , Mouchel Jean-Marie , Thévenot Daniel R.
Published: May 2018

Particulate heavy metals and hydrocarbons have been measured in Paris urban area during dry and wet weather periods. A 18 months campaign realised upstream Paris, in the river Seine, has evidenced higher heavy metals concentrations during summer than winter. Summer campaigns demonstrate a strong impact of Paris urban area and its discharges. The direct impact of highly polluted urban overflows into River Seine has been evidenced as a weak immediate but significant retarded discharge of particulate toxic metals. Ratios of significant PAH's allows a better understanding of sources and transport of hydrocarbon in urban areas. Furthermore, relation of these impacts to those observed for heavy metals brings useful information on effects of urban storm drainage.
Introduction of plate settler for combined sewer overflow treatment
Authors: Takayanagi Enao , Abe Takashi , Taruya Takao , Fukui Satoshi
Published: May 2018

Osaka City is first in Japan to employ plate settler by means of coping with CSO. Construction of the settler at Ebie Sewage Treatment Plant was commenced in 1991, and will be completed in a few years. Prior to the construction was conducted an experiment of settling treatment using sloping-plate with an existing pre-aeration tank. The detention time in the experiment device was about 10 minutes to attain an average removal rate of 70% for influent SS.

This report describes the experiment of the settling treatment using sloping-plates, and outlines the design of plate settler that are currently under construction.
Designing outlet characteristics for optimal wetland performance
Authors: Somes Nicholas L. G. , Wong Tony H. F.
Published: May 2018

Central to the hydrological and botanical design of constructed wetlands for stormwater quality management is the proper control of their hydrologic regime. The hydrologic regime, defined as the probabilistic distribution of inundation depth in the wetland, reflects the inherent variability of storm inflows to the wetland and is directly influenced by the discharge characteristics of the outlet structure of the wetland. The influence of three typical outlet structures on the hydrologic regime of a hypothetical wetland was investigated using a continuous simulation approach. The three outlet types investigated were that of a culvert, a riser and a siphon. Simulations found that all three devices provides equally effective control of the ability of the wetland to capture and detain storm runoff but can have different influence on the hydrologic regime of the wetland. The siphon-controlled wetland was found to exhibit a more even distribution of inundation depth compared to the other two outlet types.
Guidelines for hydrodynamic calculations on urban drainage in the Netherlands: backgrounds and examples
Authors: van Luijtelaar H. , Rebergen E. W.
Published: May 2018

In The Netherlands guidelines are presented describing a system for the input and performance of hydrodynamic calculations on urban drainage. These guidelines are a framework of starting-points and conditions in which the calculations are made. In addition default values for some of the calculation parameters are defined. In this article some backgrounds are presented on the rainfall: standard events, time series and a runoff model. A brief analysis and check of calculation results are given on a so called ‘didactic’ sewer system.
Conjunctive monitoring of a sewer system and receiving waters in a medium sized community
Authors: Sztruhar D. , Sokac M. , Hyanek L. , Frankova E. , Rusnak D. , Namer J. , Stanko S. , Marsalek J.
Published: May 2018

Results of an urban runoff monitoring program are presented. Combined sewer overflow (CSO) samples were analysed for suspended solids (SS), five-day biochemical oxygen demand (BOD5), total chemical oxygen demand (COD), total organic carbon (TOC), heavy metals (Cu, Zn, Cd, Pb, Ni), nitrogen compounds, biological and microbiological constituents. Study results indicate that CSOs largely contribute to the organic pollution of the local receiving streams. Cumulative pollution impacts were caused by sedimentation of suspended solids in the waste water treatment plant effluent discharged throughout the year. However, comparison of the various pollution sources indicated that pollution problems in the receiving waters were caused not only by the municipal effluents from the Town of Malacky, but also by diffuse, agricultural pollution characterised by elevated loads of nutrients (N and P), as well as by release of heavy metals (mainly Zn) from the surrounding area.
Risk assessment of Campylobacter species in shellfish: identifying the unknown
Authors: Teunis P. , Havelaar A. , Vliegenthart J. , Roessink G.
Published: May 2018

Shellfish are frequently contaminated by Campylobacter spp, presumably originating from faeces from gulls feeding in the growing or relaying waters. The possible health effects of eating contaminated shellfish were estimated by quantitative risk assessment. A paucity of data was encountered necessitating many assumptions to complete the risk estimate. The level of Campylobacter spp in shellfish meat was calculated on the basis of a five-tube, single dilution MPN and was strongly season-dependent. The contamination level of mussels (<1/g) appeared to be higher than in oysters. The usual steaming process of mussels was found to completely inactivate Campylobacter spp so that risks are restricted to raw/undercooked shellfish. Consumption data were estimated on the basis of the usual size of a portion of raw shellfish and the weight of meat/individual animal. Using these data, season-dependent dose-distributions could be estimated. The dominant species in Dutch shellfish is C. lari but little is known on its infectivity for man. As a worst case assumption, it was assumed that the infectivity was similar to C. jejuni. A published dose-response model for Campylobacter-infection of volunteers is available but with considerable uncertainty in the low dose region. Using Monte Carlo simulation, risk estimates were constructed. The consumption of a single portion of raw shellfish resulted in a risk of infection of 5–20% for mussels (depending on season; 95% CI 0.01–60%). Repeated (e.g. monthly) exposures throughout a year resulted in an infection risk of 60% (95% CI 7–99%). Risks for oysters were slightly lower than for mussels. It can be concluded that, under the assumptions made, the risk of infection with Campylobacter spp by eating of raw shellfish is substantial. Quantitative risk estimates are highly demanding for the availability and quality of experimental data, and many research needs were identified.
The effect of type of water supply on water quality in a developing community in South Africa
Authors: Genthe B. , Strauss N. , Seager J. , Vundule C. , Maforah F. , Kfir R.
Published: May 2018

Efforts to provide water to developing communities in South Africa have resulted in various types of water supplies being used. This study examined the relationship between the type of water supply and the quality of water used. Source (communal taps, private outdoor and indoor taps) and point-of-use water samples were examined for heterotrophic plate counts (HPC), total and faecal coliforms, E. coli, and coliphages. Ten percent of samples were also analysed for enteric viruses, Giardia and Cryptosporidium. Approximately 320 households were included in a case-control study. In addition, a cross-sectional study was conducted. Both studies examined the relationship between different types of water facilities and diarrhoea among pre-school children. The source water was of good microbial quality, but water quality was found to have deteriorated significantly after handling and storage in both case and control households, exceeding drinking water quality guideline values by 1-6 orders of magnitude. Coliphage counts were low for all water samples tested. Enteric viruses and Cryptosporidium oocysts were not detected. Giardia cysts were detected on one occasion in case and control in-house samples. Comparisons of whether in-house water, after handling and storage, complied with water quality guideline values demonstrated households using communal taps to have significantly poorer quality than households using private outdoor or indoor taps for HPC and E. coli (χ2 = 14.9, P = 0.001; χ2 = 6.6, P = 0.04 respectively). A similar trend (although not statistically significant) was observed for the other microbial indicators. The cross-sectional study demonstrated an apparent decrease in health risk associated with private outdoor taps in comparison to communal taps. This study suggests that a private outdoor tap is the minimum level of water supply in order to ensure the supply of safe water to developing communities.
Microbiological quality of bottled water
Authors: Fewtrell L. , Kay D. , Wyer M. , Godfree A. , O'Neill G.
Published: May 2018

Bottled water is now the biggest selling soft drink in Europe (van Musschenbroek, 1995) with sales topping 700 million litres in 1994 in the UK alone (Natural Mineral Water Association, pers comm). As part of a wide ranging UK Department of the Environment Programme to assess possible risks from the consumption of drinking water from all sources, a survey of the microbiological quality of still bottled water, at the point of sale, was conducted. A total of 17 different brands of still water (both natural mineral and other bottled water) in a variety of different containers (plastic and glass, clear and coloured) were tested for total colony counts at 22°C and 37°C, total coliforms, Escherichia coli, Pseudomonas aeruginosa, aeromonads, faecal streptococci and sulphite-reducing clostridia. Bottles were purchased from various suppliers in order to obtain a range of different sell by dates.
Inactivation of indigenous bacteria in water by ozone and chlorine
Authors: Joret J. C. , Mennecart V. , Robert C. , Compagnon B. , Cervantes P.
Published: May 2018

The aim of this study was to compare the level of removal and inactivation of indigenous bacteria during drinking water production as evaluated by culture techniques and epifluorescent microscopic counts of metabolically active bacteria (in situ respiring bacteria i.e. able to metabolise CTC: cyano 2,3-ditolyl tetrazolium chloride). Two sets of experiments were designed: a) bacterial counts through a full scale drinking water treatment plant (multibarrier treatment including coagulation-flocculation-settling, sand filtration, ozonation, biological GAC filtration, post-chlorination) and distribution system; b) benchscale disinfection studies in order to re-evaluate the C.t values necessary to inactivate laboratory grown E. coli or indigenous bacteria from water by ozone and chlorine. Main conclusions of this study are: a) significant amounts of in situ respiring bacteria (undetected by the classical culture techniques) are detected in finished water; b) the efficiency of ozone and chlorine recorded by microscopic counts of active bacteria is much less than supposed by classical enumerations of culturable bacteria; c) previous results reported in the literature may have largely overestimated the bactericidal efficiency of disinfectants used for producing drinking water.
Prevention of bacterial growth in drinking water distribution systems
Authors: Piriou Ph. , Dukan S. , Levi Y. , Jarrige P. A.
Published: May 2018

Of the many causes of drinking water quality deterioration in distribution systems, biological phenomena are undoubtedly the subject of the most study. They are also the most closely monitored because of short-term public health risks. A determinist model was developed to predict bacterial growth in the network and to locate the zones where the risks of biological proliferation are the highest. The model takes into account the growth of suspended and fixed bacteria, the consumption of available nutrients in the bulk water and in the biofilm layer, the influence of chlorine residual on the mortality of suspended and fixed biomass, the deposition of suspended bacteria and the detachment of biofilm cells, the influence of temperature on bacterial activity and chlorine decay. The model is constructed using hydraulic results previously generated by PICCOLO, the SAFEGE hydraulic computer model and a numerical scheme to predict bacterial count at each node and on each link of a network. The model provides an effective and each way to visualise on a computer screen variations in water quality in the network. The first model calibration was done using data obtained from a pipe loop system pilot. A validation of the model has been carried out by means of measurement campaigns on various real networks. This predictive model of bacterial growth in distribution systems is a unique approach for the study, diagnosis and management of distributed water quality. This tool is helpful for proposing strategies for the management of distribution systems and treatment plants and to define conditions and locations of high bacterial counts in relation to hydraulic conditions.