bluuebunny/crossref_metadata_2025 huggingface dataset:
Improvement of biodegradation of organic substance by addition of phosphorus in biological activated carbon
Authors: Nishijima Wataru , Shoto Eiji , Okada Mitsumasa
Published: May 2018

The purposes of this study are to clarify the behavior of phosphorus in coagulation/sedimentation process, and to evaluate the effects of phosphorus addition into biological activated carbon (BAC) treatment on the biodegradation of organic substances. Conventional coagulation/sedimentation reduced phosphorus concentration to very low level, that is, 0.002–0.004 mgP.l−1 in water containing less than 0.063 mgP.l−1. In continuous experiment, the biodegradation rate of glucose in the BAC with adsorbed phosphorus before the start of operation was 5 times higher than that in the BAC without adsorbed phosphorus. The rate of increase in bacterial population was higher in the BAC with adsorbed phosphorus compared to the BAC without adsorbed phosphorus. The biodegradation rate of glucose in the BAC without adsorbed phosphorus increased significantly by addition of phosphorus into influent. Therefore, growth and biodegradation activity of attached bacteria on BAC was limited by phosphorus of low concentration in the influent treated by coagulation/sedimentation. Adsorption of phosphorus on activated carbon before the start of operation and/or addition of phosphorus in influent will be effective to improve the biological activity on BAC.
The effects of oxygen delignification, complete chloride dioxide substitution, and biological treatment on bleached kraft mill effluent quality
Authors: Hasegawa Mark M. , Barton Douglas A.
Published: May 2018

The effects of bleaching modifications on the biotreatability of the resulting Adsorbable Organic Halides (AOX) were studied using laboratory-scale bioreactors and mill-scale bleach plant filtrates. Under conventional pulping/bleaching conditions, biological removal of AOX averaged 40 percent. After modification to oxygen delignification and complete ClO2 substitution, the removal efficiency increased to 47 percent. Under the treatment conditions employed, the eight percent increase was found to be statistically significant at a 95 percent confidence level. These results indicate that AOX biotreatability efficiencies following bleaching sequence modifications to oxygen delignification and complete ClO2 substitution remain at least as high as those observed prior to such modifications.
Resistance of EDTA and DTPA to aerobic biodegradation
Authors: Hinck M. L. , Ferguson J. , Puhaakka J.
Published: May 2018

Ethylenediamine tetraacetic acid (EDTA) and diethylenetriamine pentaacetic acid (DTPA) are synthetic chelating agents that form stable complexes with most metals and are used in a variety of industrial applications. They are increasingly used with peroxide and ozone bleaching of wood pulp to sequester iron and manganese. These chelates have been widely reported to either resist degradation or undergo slow biodegradation. EDTA and DTPA have few known environmental impacts in receiving waters.

A study was conducted to assess the biodegradability of EDTA and DTPA and to determine if these compounds could be transformed in conventional effluent treatment processes. Four dissimilar inocula were used in batch and continuous aerobic tests using a variety of enrichment techniques. Selection pressure was applied to bacterial populations by providing EDTA and DTPA as sole carbon sources. Additionally, experiments were conducted using degraders of chemically similar compounds nitrilotriacetic acid and triethanolamine. In all experiments, the results showed that neither EDTA or DTPA are biodegraded under aerobic conditions.
In line biological water regeneration in a zero discharge recycle paper mill
Authors: Habets Leo H. A. , Knelissen Heins J.
Published: May 2018

The recycled paper group of KNP-BT operates in total 12 paper and board mills in Western Europe. All together the output of recycled product is 1.5 million tpy, of which approx. 50% is testliner and corrugated medium. The company has been a pioneer in process water closure for more than 20 years and several of its mills were already operating totally effluent free, long before the term “zero effluent” was invented.

Some advantages of this way of operation are energy conservation and no charges for effluent discharge. Disadvantages are amongst others, accumulation of organic compounds, increased salt content, water hardness and volatile fatty acid build up.

One of the fluting and testliner mills in the group is Zülpich Papier, which is currently going through an extension phase from 170.000 tpy to 340.000 tpy. This particular mill has been operated under complete effluent free circumstances almost 20 years. However, even though the new machine is to be put into operation in October 1996, a biological process water regeneration plant has been put on stream already in September 1995 in order to collect experience with the internal treatment and to have everything running smoothly by the time the new machine is started.

The in line treatment consists of an anaerobic and an aerobic stage. During the first stage the dissolved organic components like carbohydrates and volatile fatty acids are converted into methane gas. At the same time, sulphate reducing bacteria convert sulphate into hydrogen sulphide, which is stripped out by the biogas. During the subsequent aerobic stage, residual organic components are oxidized into carbonate, which precipitates with calcium ions into the aerobic sludge and accumulates as calcium carbonate. These are a few examples of what is being achieved. Due to several favourable reactions in the biological stage, the process water quality has improved drastically for the following criteria:

Odour, corrosion properties, salt content (conductivity), hardness, viscosity, COD-level and pH. Also components like stickies, waxes and colloidal material are presumably being degraded during the biological regeneration process.

In the paper a description is given of the plant, as well as an overview of the main improvements of the process water quality during the first four months of in line biological treatment.
The closure of water circuits by internal thermophilic (55 and 70°C) anaerobic treatment in the thermomechanical pulping process
Authors: Jahren Sigrun J. , Rintala Jukka A.
Published: May 2018

The suitability of an internal thermophilic anaerobic treatment system for closing the water circuits in thermomechanical pulp (TMP) production was studied. The dissolution of wood organics in the water circuit was simulated by hot disintegration of TMP pulp, while the water system closure was simulated by repeated hot disintegration of TMP pulp with recirculated water. The upflow anaerobic sludge blanket (UASB) reactors were started at 55 and 70°C with mesophilic inoculum, and stable performances were established within 60 days at both temperatures. Closing the water circuits without internal treatment rapidly resulted in increased chemical oxygen demand (COD) in the recirculated water. In the closed, internally treated water circuits, the UASB reactors removed all the COD and ultraviolet absorbance at 280 nm (UV280; estimation for lignin content) dissolved in the recirculated water during the hot disintegration of the TMP pulp (carbohydrates were not dissolved). The results of this study suggest that thermophilic anaerobic treatment could be feasible at least as a part of an internal purification system to close the water circuit in the TMP process.
Alternatives for treating recirculated newsprint whitewater at high temperatures
Authors: Tardif Oliver , Hall Eric R.
Published: May 2018

Four treatment alternatives were investigated for the removal of dissolved and colloidal substances at high temperatures from a simulated closed-system mechanical newsprint whitewater: (i) sequenching batch reactor treatment (SBR), (ii) ultrafiltration (UF), (iii) biological treatment followed by UF (SBR⊕UF) and (iv) membrane bioreactor (MBR) treatment. Contaminants investigated included resin and fatty acids (RFA), dissolved organic carbon (DOC), dissolved chemical oxygen demand (DCOD) and total dissolved solids (TDS). Ultrafiltration alone yielded excellent FA removals at temperatures ranging from 20 to 60°C, but only fair removals (9 to 42%) of TDS, dissolved COD, DOC and RA. Removal efficiencies were generally enhanced when using a membrane of a smaller pore size but did not vary with temperature. The SBR was effective at removing contaminants at temperatures ranging from 20 to 40°C (up to 100% of the RA, 96% of the FA, 76% of the DCOD and 34% of the TDS were removed). However, the performance of the SBR was poor at 45 and 50°C. Batch ultrafiltration of SBR pre-treated whitewater enhanced the removal of target contaminants, compared to SBR treatment alone. The MBR was judged to be the preferable treatment process at high temperatures. It yielded consistent removal efficiencies at temperatures ranging from 40 to 55°C, removing up to 100% of RA and FA, 84% of DCOD and 37% of TDS.
The influence of anoxic conditioning of sludge on enhanced AOX (adsorbable organic halogen) removal in aerobic biological treatment systems
Authors: Hua-Wu Liu , Liss Steven N. , Allen D. Grant
Published: May 2018

The increasingly stringent limits on the discharge of adsorbable organic halogen (AOX) from bleached kraft pulp mills have resulted in a need to optimize the performance of biological wastewater treatment systems with respect to the removal of these compounds. To investigate whether anoxic conditioning of sludge can enhance AOX removal in activated sludge systems, a series of batch experiments was conducted where reactors were seeded with various proportions of activated and anoxic-conditioned sludges. AOX removal was found to be significantly enhanced through the addition of anoxic-conditioned sludge to activated sludge, resulting in overall AOX removal of up to 75%. The extent of enhancement ranged from 3 to approximately 10% as the conditioning time was increased from 5 to 20 days. The benefit then declined as the conditioning times increased further beyond 20 days and up to 30 days. The effect of conditioning time on COD removal followed a similar trend as for AOX removal. An optimal AOX removal was achieved when the proportion of conditioned sludge within the biomass was 30%. A good correlation between the enhanced AOX removal and increasing levels of facultative bacteria developed in the conditioned sludge was observed. The addition of sulphate into the sludge during conditioning further increased the enhancement of AOX removal when compared to sludges conditioned under nitrogen.
Pretreatment requirements and status of industrial effluents in the greater Istanbul area
Authors: Sarikaya H. Z. , Eroglu V. , Sevimli M. F. , Öztürk I.
Published: May 2018

Evaluation of the industrial pretreatment plants in Istanbul Metropolitan area is presented. Out of 7899 industries located in Istanbul, 1420 of them require pretreatment to meet the discharge criteria. Currently, there are 532 pretreatment works which treat 82.6 percent of the industrial wastewaters. Discharge standards and the compliance monitoring system for the industrial wastewater discharges into the public sewers as applied by the Istanbul Water and Sewerage Administration are discussed. The performance data of the pretreatment plants are given based on the percent non-compliance and percent removal efficiency figures determined for different categories of industry. Problem areas in terms of industrial sector and in terms of quality parameters are identified.
Feedback of 2,3,7,8-TCDF (tetrachlorodibenzofuran) from aerated lagoon sediments
Authors: Pagoria P. S. , Kerfoot G.
Published: May 2018

Process changes at a bleached softwood pulp mill in Canada essentially eliminated generation of 2,3,7,8-TCDF (tetrachlorodibenzofuran). However, aerated lagoon sediment deposits contained significant TCDF residuals from historic bleaching practices. The aerated lagoon discharge TCDF concentration was elevated and believed to result from TCDF feedback from lagoon sediment. A sampling program was undertaken to quantify TCDF in wastewater, suspended solids, and sediment. Measurements found water column TCDF concentrations significantly increased in the lagoon first bay front half and then declined as generated biological solids settled out in downstream lagoon segments. A simplified mass balance found sediment TCDF was being redistributed from lagoon front to back. Wastewater TCDF level increased where soluble BOD removal activity was greatest and was independent of vertical or spatial differences in sediment TCDF concentration. Increases in first bay wastewater TCDF appeared to be declining with time concurrent with reduction in final discharge TCDF concentration below the regulatory limit. Net feedback from first bay sediment was 19.46 mg/day, but net export in the lagoon wastewater discharge was only 1.40 mg/day. It was estimated first bay historic deposits of TCDF would be depleted in 1 to 4 years. Additional wastewater samples were collected 14 months later to confirm feedback decline at internal lagoon locations. Redistribution of sediment TCDF was still occurring from lagoon fron to back, but lagoon bay 1 gross TCDF feedback from sediment had declined by 88%.
The use of the kaldnes suspended carrier process in treatment of wastewaters from the forest industry
Authors: Dalentoft Eva , Thulin Peter
Published: May 2018

One pilot plant study and two full scale studies have been carried out seeking for the optimal use of the Kaldnes suspended carrier process in treatment of wastewaters from the forest industry. The wastewater used in all three cases came from secondary fiber mills. The studies show that the Kaldnes process as a highly loaded stage (typically 15-25 kg COD/m3·d) in series with an activated sludge stage forms an efficient, stable and competitive combination process both regarding investment and operating costs. This is especially true when treating wastewaters with a composition that makes them unsuited for treatment in an activated sludge process. The flexibility and compactness of the Kaldnes suspended carrier process also makes it an ideal choice for upgrading of existing treatment plants.
Electrochemical oxidation pretreatment of refractory organic pollutants
Authors: Chiang Li-Choung , Chang Juu-En , Tseng Shu-Chuan
Published: May 2018

Refractory pollutants, including lignin, tannic acid, chlortetracycline, and EDTA, were destroyed by an electrochemical oxidation method to evaluate the applicability of this method for industrial wastewater pretreatment. Operation parameters, such as supporting electrolyte, current density, and electrolyte concentration, have been investigated for their influences on COD removal efficiencies during electrolysis. In addition, gel permeation chromatography (GPC), Microtox test, and total organic halogen (TOX) analyses were performed to monitor the changes of organic characteristics of these refractory pollutants. Experimental results show that, among sulfate, nitrate, and chloride, chloride was the best supporting electrolyte, and during electrolysis, both COD and color removal efficiencies were improved by increasing current density and chloride concentration. From GPC analysis results, the electrochemical oxidation process readily destroys high-molecular-weight (HMW) organics. Microtox test results also show that the process can reduce the toxicity of these refractory organic compounds. In addition, TOX concentrations were found to increase at the beginning but then decline during the electrolysis. The above results suggest that the electrochemical oxidation process, which has good efficacy for detoxification and destruction of refractory pollutants, is a promising method for wastewater pretreatment.
On-site treatment of dyeing wastewater by a bio-photoreactor system
Authors: Li X. Z. , Zhao Y. G.
Published: May 2018

Synthetic dyeing wastewater consisting of the three different commercial dyes with different strengths of COD (about 900 and 3000 mg/l respectively) was initially treated by an aerobic biological process, Intermittently Decanted Extended Aeration reactor (IDEA), for BOD removal, and then continuously treated by a TiO2 sensitised photoreactor for a further COD removal and decolorization. The catalysed photooxidation process can degrade those non-biodegradable organic substances in the effluent treated by the IDEA process and also decolorize the effluent completely. It is also found that some nonbiodegradable organic substances can be converted to biodegradable forms by the sensitized photo-oxidation reaction. A bio-photoreactor system was designed to combine this photocatalytic reactor with the IDEA reactor for the treatment of dyeing wastewater. The performance of this combined bio-photoreactor system with and without recirculation was investigated and compared. The system with recycled water has similar efficiency for decolorization and COD removal to that without recirculation, but has a high capacity to eliminate the effects caused by a shock loading, and also the system can treat dyeing wastewater with a higher organic concentration.
Evaluation of inorganic adsorbents for the removal of problematic textile dyes and pesticides
Authors: Lambert S. D. , Graham N. J. D. , Sollars C. J. , Fowler G. D.
Published: May 2018

This paper evaluates three inorganic adsorbents (activated bauxite, fullers earth and a synthetic clay), relative to activated carbon, for the removal of several representative contaminants of major concern and frequent occurrence in UK textile industry effluents; reactive dyes, pentachlorophenol and Propetamphos. The results indicate that, for the removal of reactive dyes, the synthetic clay was the most effective adsorbent over the pH range from pH 5.5 to pH 8.5 and temperature range from 20 to 40°C, although comparable dye removals were exhibited by activated carbon under neutral and alkaline conditions. Under acidic conditions activated bauxite was as effective as activated carbon. Fullers Earth was largely ineffective. With regard to the removal of pesticides activated carbon was highly effective, whereas the three inorganic adsorbents showed negligible removals.
Feasibility analysis of print pastes co-disposal in anaerobic sludge digesters
Authors: Bonomo L. , Rozzi A. , Malpei F.
Published: May 2018

Significant amounts of residual print pastes are produced by the industrial textile settlements of the Como area (Italy). Currently, these wastes are directly discharged in the sewer but it is unlikely that in the future this treatment through POTW will be further allowed. Therefore alternative ways of collection and disposal must be evaluated. The most suitable processes appear to be: drying, followed by incineration or landfilling, or anaerobic co-treatment with sewage sludge. The latter option was investigated at pilot scale and a technical feasibility analysis of the full-scale solution was carried out. Results are presented and discussed with reference to the impact that this solution would have on the performance of POTW and on the treatment costs of textile industrial wastewater.
Characterization of tannery wastewaters for pretreatment - selected case studies
Authors: Ates E. , Orhon D. , Tünay O.
Published: May 2018

Wastewater characterization is an integral part of treatment and management strategies for industrial effluents. This paper outlines the results of detailed characterization studies on three different tannery complexes. It evaluates, aside from raw wastewater quality in terms of major polluting parameters, the impact of physical and chemical settling on wastewater characteristics. Emphasis is placed upon homogenization and sulfide removal potential. Chemically treated wastewater is further studied for assessing COD fractionation, presently used as significant modelling information for biological treatability.
Coagulation-flocculation pretreatment of high-load chemical-pharmaceutical industry wastewater: mixing aspects
Authors: Torres Luis G. , Jaimes Jorge , Mijaylova Petia , Ramírez Esperanza , Jiménez Blanca
Published: May 2018

The selection of a coagulant-flocculant agent which, based on the maximum chemical oxygen demand removal, warrants the best performance of the removal system for a very complex high-load chemical-pharmaceutical industry wastewater, is described. A total of 23 coagulants/flocculants was tested, including salts, poly-hidroxyaluminates, synthetic polymers as well as natural gums. In a second stage, some mixing aspects were studied. The effects of the specific impeller, the agitation speed during the coagulation and flocculation stages, and the absence or presence of baffles were evaluated in a six-place agitation system. The conventional impellers were replaced by the following types of propellers: Rushton, marine, A310 (Lightning), three flat blades, 45° inclined six blades, and conventional flat blade propeller. It was demonstrated that the appropriate coagulation-flocculation system is capable of diminishing the COD, the apparent color and the dissolved solids up to 40.6, 25.6 and 39.4%, respectively. The best results were observed when using BL-5086, guar gum, Niad II-3, Niad II-4 and locus beam gum. The impeller performance was highly dependent on the agitation speed for each fixed system. With respect to the mixing aspects, it was shown that the selection of the right propeller for the coagulation and flocculation stages is crucial in determining the quality of the treated water, as well as the quantity and quality of the residual sludges generated in the process.
Reduction in residual COD in biologically treated paper mill effluents by means of combined ozone and ozone/UV reactor stages
Authors: Oeller H.-J. , Demel I. , Weinberger G.
Published: May 2018

Lab-scale tests have been conducted on the reduction of residual COD in biologically purified effluents from mills with integrated waste paper treatment plants and/or TMP lines. For this purpose, waste water samples were subjected to ozonization or a combined ozone/UV treatment at varied temperatures and pHs. The influence of ozone on the biodegradability of biologically part-treated effluents was studied by means of the Zahn-Wellens test. For specific ozone consumption rates < 2.5 g O3/g eliminated COD, COD elimination rates of up to 82% and DOC elimination rates of up to 64% were obtained. Ozone consumption was considerably higher for a combined ozone/UV treatment or treatment at pH > 9 or at elevated temperatures (40°C). For colour stripping of the waste waters and for destroying the surfactants contained in them, ozone additions of up to 80 mg O3/l waste water were required. The bioavailability of effluents that have been part-treated biologically in trickling filters or anaerobic stages to COD > 500 mg/l and BOD5/COD > 0.2 cannot be positively influenced by ozonization with up to 1.8 g O3/l waste water. On the other hand, in fully biologically treated effluents (COD < 500 mg/l), ozonization brought about a rise in the BOD5/COD ratio from an initial < 0.05 to a maximum of 0.37 - an observation which clearly demonstrates an increase in bio-degradability.
Electrochemical treatment of vinasse from beet molasses
Authors: Vlyssides A. G. , Israilides C. J. , Loizidou M. , Karvouni G. , Mourafeti V.
Published: May 2018

In this work the results from a new technique are presented in which the vinasse from beet molasses is treated by electrolysis. By this technique, sodium chloride is added in the wastewater and the mixture passes through a electrolytic cell. A number of experiments was run in an laboratory scale pilot plant. In the electrochemical process chlorine, chlorates and other oxidants are produced. Because of the strong oxidizing potential of the chemicals produced the organic pollutants were wet oxidized to carbon dioxide and water. The results obtained have shown that the treatment depends on the catalytic activity of the anode used, the COD loading rates and the pH of the solution. The best results for sodium chloride concentration 4%, temperature 42°C, 72,000 mg/l influent COD conc were found to be the following: pH 9.5 and vinasse feed rate 30 ml/min. Under these conditions the COD reduction was 20 g/h/A/m2 and the COD conc of the effluent was 8000 mg/l. These results have shown that the electrochemical treatment of beet vinasse can be efficient and feasible.
Effect of synthetic and natural coagulant on lignin removal from pulp and paper wastewater
Authors: Ganjidoust H. , Tatsumi K. , Yamagishi T. , Gholian R. N.
Published: May 2018

The effects of synthetic polymer (HE, PEI, and PAM) and natural polymer (chitosan) and chemical (alum) coagulant on the removal of lignin (black liquor color, and TOC) from pulp and paper industrial wastewater were investigated. It was observed that the formation of flocs was rapidly taking place which was an indication of fast coagulation flocculation process. PAM which is a nonionic polymer had poor effect as compared to HE and PEI which are cationic polymers. Both HE and PEI resulted in good brown colored precipitate at pH of about 6. These coagulant resulted in removal of about 80% of color and 30% of TOC from alkaline (black liquor) wastewater by gravity settling in 30 minutes. alum resulted in good precipitate with less than 30 minutes settling time by gravity. The percent color removed by alum was the same as the one removed by HE or PEI, but the TOC removed was higher by this chemical coagulant (about 40%). The natural coagulant, chitosan, resulted in the highest removal in both color and TOC as compared to both synthetic polymers and chemical coagulant. Up to 90% of color and 70% of TOC were observed to be removed by chitosan.
Treatment of wastewater from the potato chips and snacks manufacturing industry
Authors: Hadjivassilis Ioannis , Gajdos Stanislav , Vanco Dusan , Nicolaou Michael
Published: May 2018

A small industrial effluent treatment plant has been designed and installed for the treatment of wastewater from a potato chips and snacks factory. The total daily flow rate to the plant was 115 m3/d, while the influent COD mass flux was 838.7 kg/d and the BOD mass flux was 626.7 kg/d. The applied method of treatment is a simple upflow anaerobic reactor with internal settling and gas collection units, followed by aerobic treatment based on the activated sludge process with diffused air system. The quality of the treated water is better than requested and the overall treatment process efficiencies are 99.2% for COD removal and 99.5% for BOD5 removal. The results of the operation of the plant during the first five months are examined and described in this paper.
Application of membrane technology in the pretreatment of cheese dairies wastes and co-treatment in a municipal conventional biological unit
Authors: Papachristou Eleftheria , Lafazanis Costas T.
Published: May 2018

A great number of cheese dairies and dairy industries in Greece are disposing their wastes, mainly cheese whey, either on land or in surface receivers, in large quantities creating a major environmental problem. A typical agricultural and pastoral provincial town of 70,000 inhabitants, Trikala, became the starting point of this research. A co-treatment of the urban sewage and the dairy wastes in the municipal treatment plant was recommended. The successful application of the above statement is based primarily on the pretreatment of the cheese dairies wastes. So far for cheese whey the recovery of the lactose serum in the contemporary central unit applying membrane technology has been suggested. As far as the wastewaters of the washing and refrigeration are concerned a pretreatment is required for the defatting in a grease trap, the grating, the adjustment of pH and the equalisation in an appropriate tank. Finally, this research has also focussed on the importance of membrane technology in improving the quality of milk and cheese production.
An assessment of the quality and treatment of detergent wastewater
Authors: Papadopoulos A. , Savvides C. , Loizidis M. , Haralambous K. J. , Loizidou M.
Published: May 2018

Removal efficiency of organic load from a detergent wastewater by a bench scale physical-chemical treatment is reported. The results of the wastewater characterisation showed that the concentrations of the organic matter were very high, expressed as COD, ranging from 2400-26,400 mg/l, while the biodegradable portion was very low, since the BOD/COD ratio was low. These values indicate that organic compounds are not easily subjected to biological treatment. In addition, methylene blue active substances appeared in high concentrations as well as sulphates and ammonia.

The experiments for the treatment of the wastewater were performed using various chemicals such as lime, alum and polyelectrolyte. The use of lime gave a 26% average COD removal, while by using alum a slightly lower removal was achieved, 23%. The use of lime (pH=9-10) in combination with alum led to a 41% COD reduction. Similar removal was achieved by using alum (pH=5-6) in combination with lime, 43%. Finally, the addition of polyelectrolyte in the systems of lime and alum did not improve total removal of organic matter giving reductions of 46% and 48%, respectively.
Studies on hydrogen production by continuous culture system of hydrogen-producing anaerobic bacteria
Authors: Kataoka Naoaki , Miya Akiko , Kiriyama Koichi
Published: May 2018

Characteristics of continuous hydrogen production and fatty acid formation by an active hydrogen-producing anaerobic bacterium, Clostridium butyricum strain SC-E1, was examined under vacuum and non-vacuum culture systems. The continuous cultures were performed using 1040 ml anaerobic glass bottles containing 600 ml of medium including glucose and polypeptone at a concentration of 0.5 or 1.0% as substrate, and were conducted at pH 6.7, hydraulic retention time (HRT) 8h, and 30°C on a reciprocal shaker. The non-vacuum cultures at 16 days of incubation showed 2.0 to 2.3 mol-H2/mol-glucose and 1.4 to 2.0 mol-H2/mol-glucose of hydrogen productivity at 0.5 and 1.0% of substrate concentration, respectively. The vacuum cultures conducted at 0.28 atm gave 1.8 to 2.3 mol-H2/mol-glucose and 1.3 to 2.2 mol-H2/mol-glucose of hydrogen productivity at 0.5 and 1.0% of substrate concentration, respectively. The fatty acid production from the vacuum cultures exhibited approximately the same yield of fatty acids as those of the non-vacuum cultures. It was concluded that the maximal hydrogen production potential by anaerobic bacteria is 1.3 to 2.2 mol-H2/mol-glucose, which is less than 50% of theoretical. In addition, the total hydrogen production rate by a two-stage bioreactor consisting of a 1-litre anaerobic fermenter (HRT 10h) and a 4-litre photobioreactor (HRT 36h) feeding at 2.4-litre of 1.0% glucose per day was estimated at 1.4 to 5.6 mol-H2/mol-glucose, which is 12 to 47% theoretical.
Methanogenesis in sediments from deep lakes at different temperatures (2–70°C)
Authors: Nozhevnikova Alla N. , Holliger C. , Ammann A. , Zehnder A. J. B.
Published: May 2018

Methanogenic degradation of organic matter occurs in a wide temperature range from psychrophilic to extreme thermophilic conditions. Mesophilic and thermophilic methanogenesis is relatively well investigated, but little is known about low temperature methanogenesis and psychrophilic methanogenic communities. The aim of the present work was to study methanogenesis in a wide range of temperatures with samples from sediments of deep lakes. These sediments may be considered deposits of different types of microorganisms, which are constantly exposed to low temperatures. The main question was how psychrophilic methanogenic microbial communities compare to mesophilic and thermophilic ones.

Methanogenesis in a temperature range of 2–70°C was investigated using sediment samples from Baldegger lake (65 m) and Soppen lake (25 m), Switzerland. Methane production from organic matter of sediments occurred at all temperatures tested. An exponential dependence of methane production rate was found between 2 and 30°C. Methanogenesis occurred even at 70°C. At the same time stable methane production from organic matter of sediments was observed at temperatures below 10°C. Methanogenic microbial communities were enriched at different temperatures. The communities enriched at 4–8°C had the highest activity at low temperatures indicating that a specific psychrophilic community exists. Addition of substrates such as cellulose, volatile fatty acids (butyrate, propionate, acetate), methanol and H2/CO2 stimulated methane production at all temperatures. H2/CO2 as well as methanol were directly converted to methane under thermophilic conditions. At low temperatures these substrates were converted to methane by a two-step process. First acetate was formed, followed by methane production from acetate. When acetate concentrations were high, acetoclastic methanogenesis was inhibited at low temperatures. This reaction appears to be one of the “bottle neck” in psychrophilic methanogenesis.
Pilot study of UASB process treating PTA manufacturing wastewater
Authors: Cheng Sheng-Shung , Ho Chiou-Yuan , Wu Jer-Horng
Published: May 2018

A pilot-scale upflow anaerobic sludge blanket (UASB) reactor was employed to treat the wastewater of a purified-terephthalic-acid (PTA) manufacturing factory. The performance of UASB reactor in terms of COD removal was achieved 62% at the volumetric loading rate of 2.93 kg COD / m3/day. One of the major constituents, p-toluic acid in PTA wastewater was the refractory component due to the methyl substituent on the aromatic ring, which restricted the biodegradation performance. Moreover, from our study, it was surprising that high concentration of acetic acid would retard the degradation of aromatics in the sludge bed. A control strategy of acetic acid level in the sludge bed was suggested during the start-up period. Comparison of the anaerobic biodegradability of aromatic substituents in PTA wastewater was concluded as the following sequence: –COOH > –CHO ≥ –CH3 in terms of the derivative functional groups based on the benzoic acid. Observation of bacterial population of the sludge granules showed high diversity of syntrophic structure on the biogranular surface as well as acetoclastic methanogens.
Kinetic data and new enzymatic activities of Methanosarcina barkeri grown on methanol as the sole carbon source
Authors: Daußmann Thomas , Aivasidis Alexander , Wandrey Christian
Published: May 2018

The strictly anaerobic methanogen Methanosarcina barkeri strain Fusaro (DSM 804) was fermented on a 3-liter scale in a CSTR (continuous stirred tank reactor) to obtain almost 10 g biomass dry weight per day. The generation time of the microorganism with methanol as the sole carbon source was 6.0 h, the maximal growth rate 0.115 h−1 correspondingly.

In cell-free extracts from the fermented organism active hydrogenases were found. They reduced methyl viologen (MV⊕⊕), an artificial electron acceptor, molecular hydrogen being the substrate. This reaction was used to get electrochemical energy in a biochemical fuel cell. The maximum output of this fuel cell was 2.6 mW.

Furthermore, cell-free extracts from M. barkeri showed alcohol dehydrogenase activity under aerobic conditions when N,N′-dimethyl-4-nitrosoaniline (NDMA) was used as an artificial electron acceptor. The NDMA-dependent alcohol dehydrogenase (NDMA-ADH) was purified to homogeneity by column chromatography. It is a homodimeric enzyme consisting of subunits of 45 kDa, the native molecular mass is about 87 kDa. The enzyme is independent of free coenzyme such as NAD, NADP, FMN, FAD and F420, but it possesses a tightly but noncovalently bound NADP(H) cofactor.

The purified enzyme exhibited activity only with primary alcohols including aromatic alcohols, but methanol was not accepted. It also catalyzed the stoichiometric dismutation of aldehydes, especially long-chain aldehydes, to form a half mol of each of the corresponding alcohol and acid without addition of an electron carrier. NDMA-ADH from M. barkeri is a novel type of nicotinoprotein in methanogenic bacteria.
Hybrid fuzzy neural network for diagnosis - application to the anaerobic treatment of wine distillery wastewater in a fluidized bed reactor
Authors: Steyer Jean-Philippe , Rolland Damien , Bouvier Jean-Claude , Moletta René
Published: May 2018

In this paper, we present a hybrid approach that uses both fuzzy logic and artificial neural networks for on-line detection and analysis of problems occurring in a 120 liter anaerobic digestion fluidized bed reactor for the treatment of wine distillery wastewater. The raw data available on the process (i.e., pH, temperature, recirculation flow rate, input flow rate and gas flow rate) are preprocessed using fuzzy logic to build a vector of features (i.e., a pattern vector). This feature vector is classified into a prespecified category (i.e., a class) which is a state of the system, according to discrimination fuzzy rules. An artificial neural network is then used to classify the process states and to identify the faulty or dangerous ones. This approach was developed to handle in real time problems such as, for example, foam forming, sudden changes in the effluent to be treated (due to a change in concentration), pipe clogging (due to struvite formation) or bad temperature regulation (due to improper setting of the control parameters).
Innovative technology for the improvement of the anaerobic methane fermentation
Authors: Dohányos Michal , Zábranská Jana , Jenícek Pavel
Published: May 2018

The intensification method of anaerobic methane fermentation of sludges, based on the stimulation activity of cell lysate, was studied. The effect of lysate is caused by the still remaining activity of released enzymes and by the stimulating properties of other compounds that are present inside the cells. The anaerobic cell lysate was prepared by a thermal treatment of anaerobic sludge and the aerobic cell lysate by a partial mechanical destruction of cells of the excess activated sludge by a special adapted thickening centrifuge.

The use of cell lysate as a stimulating agent was examined in the laboratory experiments of anaerobic degradation of simple organic compounds (glucose, acetate, formate and propionate) and of complex substrates as municipal raw sludge, excess activated sludge and some pharmaceutical organic wastes. The results show a significant improvement of the removal rates of substrates and the enhancement of methane production in all cases of lysate addition. In the fermentation of raw sludges and pharmaceutical wastes with anaerobic lysate, the increment of the methane yield ranges from 38.2–61.8% and 20.2–36.7% respectively. The aerobic lysate increased the methane yield of excess activated sludge and of its mixture with primary sludge at the range of 17.1–86.4% and 24% respectively.
Temperature-phased anaerobic digestion of wastewater sludges
Authors: Han Yue , Sung Shihwu , Dague Richard R.
Published: May 2018

The temperature-phased anaerobic bioreactor (TPAB) has been under study by Dague and co-workers at Iowa State University. The temperature-phased approach involves a two-stage reactor system with the first stage operated at a thermophilic temperature (commonly 55°C) and the second stage operated at a mesophilic temperature (commonly 35°C). The purpose of laboratory study was to compare the performance of the temperature-phased system with the conventional single-stage mesophilic system for treating mixtures of primary and waste activated sludge. Of particular interest in the research was a comparison of the two systems from the standpoint of coliform reduction, volatile solids (VS) destruction, and biogas production.

The temperature-phased system achieved complete destruction of total and fecal coliforms over a range of SRTs from 11 to 28 days. The concentration of fecal coliforms in the effluent from the temperature-phased system never exceeded 1000 MPN/g total solids (TS), which can meet the U.S. Code of Federal Regulations, Title 40 (40 CFR), Part 503 coliform requirements for Class A sludge. At the optimal SRTs ranging from 11 to 17 days, the capacity of VS removal of temperature-phased system was more than double that of the conventional single-stage system. The foaming problem associated with the digestion of waste activated sludge was eliminated.
Advanced start up of UASB reactors by adding of water absorbing polymer
Authors: Imai Tsuyoshi , Ukita Masao , Liu Jun , Sekine Masahiko , Nakanishi Hiroshi , Fukagawa Masayuki
Published: May 2018

We have developed a new approach to enhance granulation by adding water absorbing polymer (WAP) particles into the inoculated digested sludge. In this study, the effect of adding WAP on formation of anaerobic granular sludge was evaluated in lab-scale UASB reactors using two typical synthetic wastewater, i.e. glucose or volatile fatty acid (VFA) mixture solution. In addition, side by side with the lab-scale experiment, a pilot-scale experiment using the VFA mixture was carried out to evaluate the availability of accelerated start-up by adding WAP. The development of granular sludge was significantly enhanced by adding WAP. Granules developed on glucose and VFAs had high methanogenic activities and good settleability. From results of lab-scale experiment, the recommended dosage of WAP was about 750 mg/l of reactor volume. The results, pilot-scale experiment, indicated the availability of accelerated start-up by adding WAP.
UASB-reactor in the fruit juice industry
Authors: Austermann-Haun Ute , Seyfried Carl Franz , Rosenwinkel Karl-Heinz
Published: May 2018

This paper presents experiences with a full scale UASB-reactor in a fruit juice factory. The focus is on demonstrating that a UASB-reactor is as suitable for campaign industries running only 2 months a year with higher concentrated wastewater as well as for the time outside the campaign when the wastewater concentrations are very low (average COD 1000 mg/l). A number of operating results and recommendations are given, resulting from the experiences in order to show solutions for handling these very different situations. Examples of recommendations are: discontinuous feeding 8 hours a day outside the campaign, removal of pellet sludge at the end of the campaign. These frame conditions provided a COD removal efficiency in the UASB-reactor consistently above 80% throughout the year. Furthermore, it is shown that the anaerobic pre-treatment of industrial wastewater is the cheapest way in regard to the running expenses.

Another point of research was the co-fermentation of the kieselguhre-sludge-mixture. Although only 10% of the load was based on this substrate at a volumetric loading rate of 3 kg COD/(m3 · d), there was a quick drop in pH to a level of 3.5 and the pellet structure of the biomass got lost.
Model development and full scale validation for anaerobic treatment of protein and fat based wastewater
Authors: Batstone Damien , Keller Jürg , Newell Bob , Newland Mark
Published: May 2018

Presented is a kinetic model simulating the biodegradation of pig abattoir (slaughterhouse) wastewater in a full scale anaerobic treatment plant. High rate anaerobic treatment of these wastes is often complicated by the presence of particulates and fats. The model developed by Costello et al. (1991) for the degradation of soluble carbohydrates and modified by Ramsay et al. (1994) for soluble proteins is further expanded to simulate the solublisation of particles and the biological degradation of fats. This approached proved well suited to describe the full breakdown of the complex component mixture found in such a wastewater.

The model is tuned using one dynamic experimental run and is validated against on two different experimental runs. Agreement between simulation and experimental results is very good on all sets of data. The importance of critical outputs such as gas production and agreement between experimental and simulation results are discussed. It is concluded that the model should be a useful tool for optimal reactor design and operation when encountering difficult wastewaters.
Full scale experience of two stage thermophilic/mesophilic sludge digestion
Authors: Oles Jürgen , Dichtl Norbert , Niehoff Hans-hermann
Published: May 2018

The general goals of anaerobic sludge stabilisation are degradation of organic substances, reduction of solids, decrease of pathogenic bacterias, improvement of dewatering capabilities and production of biogas. The anaerobic degradation process can be divided in several steps with different optimum operational conditions. This gives the possibility to design treatment plants as a two-stage process, optimizing the process conditions in each step and thereby leading to an overall increase in process efficiency. Research results in lab scale and pilot scale have shown that a two-stage digestion process with a high loaded first thermophilic (50-55°C) stage and a second stage under mesophilic (35-37°C) conditions with sufficient retention time will lead to the best results. After giving a short summary of the development of the two-stage thermophilic/mesophilic digestion process the paper will present full scale experiences with this system in Germany.
Image analysis for the study of the development of anaerobic biofilms on materials characteristic of landfilled refuse
Authors: Jones L. Robin , Watson-Craik Irene A. , Senior Eric
Published: May 2018

The techniques of anaerobic continuous culture, microscopy and image analysis were combined for the study of attachment, colonisation and biofilm development on surfaces, by strictly anaerobic microbial populations. The Anaerobic Continuous Culture Microscopy Unit (ACCMU) is a miniature continuous culture chamber, which is detachable, self-sealing, oxygen-impermeable, transparent and fits onto a microscope stage. The ACCMU system was used to record colonisation processes on different materials, by naturally occurring, mixed species, functioning microbial associations, isolated from the anaerobic layers of a landfill site. The same fields were sampled through time, allowing a colonisation rate (in μm2 d−1) to be calculated. Paper, wood, cotton and polyester fabric remained poorly or not colonised over a three week study period. Cellophane and selected non-biodegradable materials (glass, plastic and polythene) were rapidly colonised in 2–3 weeks.
Anaerobic treatment of leachate using sequencing batch reactor and hybrid bed filter
Authors: Timur H. , Özturk I.
Published: May 2018

Landfill leachate taken from a young municipal landfill site (≈3.5 years old) containing high organic contaminants (Total Organic Carbon -TOC of about 5000 mg l−1) was treated in bench-scale Anaerobic Sequencing Batch Reactors (ASBR) and an Anaerobic Hybrid Bed Filter (AHBF) at mesophilic conditions. Twenty months of testing has been conducted at varied influent leachate concentration of 546–5770 mgTOC l−1, Hydraulic Retention Time (HRT) of 10–1.5 days and Solid Retention Time (SRT) of 40–9 days in ASBR's, and influent leachate concentration of 1250–4490 mgTOC l−1 and HRT of 5.1–0.9 days in AHBF. ASBR achieved 73.9% TOC removal at maximum organic loading rate of 2.8 kgTOC m−3 d−1 at 1.5 days of HRT, and 65.3% at 0.561 kgTOC kgVSS−1 d−1 of maximum specific loading rate and 2 days of HRT. The AHBF maintained 81.4% TOC removal at 1.2 kgTOC m−3 d−1 of loading and 2.4 days of HRT. Methane conversion ratio averaged 0.742 m3CH4 kgTOC−1 removed at (STP).
Effect of maximum flood width on road drainage inlet spacing
Authors: Wong Tommy S. W. , Moh Wung-Hee
Published: May 2018

Based on the kinematic wave theory, a method has been developed for the determination of road drainage inlet spacing under the continuous grade condition. The input data required are the allowable maximum flood with, the physical characteristics of the roadway, the empirical relationship between the maximum discharge and the intercepted flow, and the rainfall intensity-duration curve. By applying the method to a roadway with the standard drainage inlet used in Singapore, the effect of maximum flood width on the inlet spacing has been assessed. The assessment shows that for a given maximum flood width, the inlet spacing is wider for roads with steeper cross and longitudinal slopes. An increase in maximum flood width gives an exponential increase in inlet spacing.