bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design of a Hybrid Reed Bed System to Achieve Complete Nitrification and Denitrification of Domestic Sewage
Authors: Cooper Paul , Griffin Paul , Humphries Stuart , Pound Adrian 
Published: May 2018

The design of vertical-flow (VF) reed beds is reviewed and the performance of the few worldwide existing hybrid systems, combining both horizontal- and vertical-flow beds, is assessed. Horizontal-flow (HF) beds are good for suspended solids removal and will remove BOD5 up to a set loading. Vertical-flow beds can achieve BOD5 removal at much higher loading rates and they are capable of complete nitrification as tertiary or secondary treatment systems. It is possible to achieve biological denitrification in horizontal-flow beds. By combining horizontal- and vertical-flow systems in the appropriate process sequence it is thus possible to produce a system which removes BOD5, TSS and achieves complete nitrification as well as substantial removal of nitrate and hence a lowered Total N.
The paper discusses the possible process options for combining horizontal- and vertical-flow systems. One example of these systems will be described in more detail. This is a flexible hybrid system being built by Severn Trent Water. Designed to treat the flow for a small village with a population of 129 it will have vertical-flow beds followed by horizontal-flow beds. The design allows for flexibility such that the size of the vertical-flow and horizontal-flow stages can be altered (for experimental purposes) to allow the design arrangement to be stressed and performance evaluated with the intention of defining the optimum loading rates for each of the stages.
The same site also has sludge drying reed beds for treating the primary sludge.
Evaluation of Consumer Attitudes on Taste and Tap Water Alternatives in Québec
Authors: Levallois P. , Grondin J. , Gingras S. 
Published: May 2018

A telephone survey carried out in 1995 in the Québec metropolitan area reached 2009 residents of four municipalities. Tap water was consumed regularly by only 50.8 percent of the consumers and bottled water by 42.7 %. Consumer dissatisfaction regarding the quality of tap water was noted. Fourteen percent were dissatisfied with the odor, and 30.6 % with the taste or flavor. Health risks, regarding ingestion of tap water, were mainly not perceived or seen only as a minor issue to consumers.
Multiple regression analysis indicated that knowledge of the source of the water was not a major determinant for selecting alternatives to tap water (e.g., bottled water or use of home treatment devices). Such use of alternatives was in fact six times higher in consumers dissatisfied with the taste of the water (OR = 6.0, p = 0.001) and only 35 % higher if people were connected to a distribution network using the St. Lawrence River as the source of supply (OR = 1.35, p = 0.01). No explanation was given for the taste problem reported.
Aerobic stabilisation criteria for BNR biosolids
Authors: Tonkovic Zlatko 
Published: May 2018

A research program was undertaken to establish the stability of waste activated sludge generated from several activated sludge treatment plants, both nutrient removal and conventional, and determine what further treatment is required to produce a substantially stabilised (ie. non-odorous) sludge.
It has been previously thought that waste activated sludge from extended aeration plants (sludge age of approximately 25 days) was sufficiently stabilised to permit dewatering and stockpiling without odour generation. However, experience at a number of treatment plants with large unaerated mass fractions for biological removal of nitrogen and phosphorus has demonstrated that these sludges are generally odorous. With the increasing requirement for on-site storage of sludge to remove pathogens prior to sludge re-use, odour generation from secondary sludges has the potential to pose significant environmental problems for many treatment plants.
The objective of the research program was to quantify the degree of stabilisation achieved in various activated sludge treatment plants, what additional aerobic treatment is required to achieve a stabilised sludge and what are the readily identified characteristics of a stabilised sludge, including volatile solids content, specific oxygen uptake rate and pathogen destruction. The phosphorus leaching characteristics were also compared between various sludges and between continuous and intermittent aerobic digestion processes.
Cost-Effective Pre-Treatment of Food-Processing Industrial Wastewater
Authors: El-Gohary F. A. , Nasr F. A. , Aly H. I. 
Published: May 2018

Performance of laboratory-scale aerobic and anaerobic systems treating food-processing wastewater was investigated. The results obtained showed that BOD and COD of wastewater discharged from a potato-chips factory can be reduced by 86% and 82% using UASB reactor at an organic loading rate (OLR) of 2.9 kg BOD/m3·d and a hydraulic retention time (HRT) of 18 hr. Corresponding results for an activated sludge system, operated at an OLR of 8.9 kg BOD/m3·d with a HRT of 6hr were 86% and 84%, respectively.
Treatment of confectionery wastewater using UASB at a HRT of 12hr and an OLR of 4.4 kg BOD/m3.d gave satisfactory results. COD and BOD removals were 92.4% and 91.5%, respectively. The use of completely activated sludge system at a HRT of 6 hr and ORL of 8.4 kg BOD/m3.d gave lower results as compared to UASB reactor. However, characteristics of the effluents produced using the two systems were in agreement with the standards regulating discharge of industrial wastewater into the sewerage system. Based on the technical and economic evaluation of the results, engineering designs were made for the selected systems.
Anaerobic treatment of Wastewater from a fish-canning factory in a full-scale Upflow Anaerobic Sludge Blanket (UASB) reactor
Authors: Pun˜al A. , Lema J. M. 
Published: May 2018

The start-up and optimisation of a 380 m3 UASB reactor (Up-flow Anaerobic Sludge Blanket) treating wastewater from a fish-canning factory was carried out. At the beginning of the operation the Organic Loading Rate (OLR) was 1 kg COD/m3·d. Then, the load was gradually increased in steps of 50% OLR until the final capacity of the system (4 kg COD/m3·d) was achieved.
Wastewater characteristics were highly dependent on the canned product (mussel, tuna, sardines, etc.). In spite of that, a stable operation working at a hydraulic retention time (HRT) of 2 days was maintained. Total Alkalinity (TA) always presented values higher than 3 g CaCO3/l, while the IA/TA ratio (Intermediate Alalinity/Total Alkalinity) was always maintained lower than 0.3.
In order to improve granulation conditions, upward velocities from 0.5 to 0.8 m/h were applied. The highest values caused the washout of non-granulated biomass from the reactor, optimum operation being achieved at an upward velocity of 0.7 m/h.
Advanced Monitoring of an Anaerobic Pilot Plant Treating High Strength Wastewaters
Authors: Puñal A. , Lorenzo A. , Roca E. , Hernández C. , Lema J. M. 
Published: May 2018

The operation of an industrial pilot scale treating wastewater from a fibreboard-processing factory was monitored by an advanced system. The plant, an anaerobic hybrid UASB-UAF bioreactor (Upflow Anaerobic Sludge Blanket-Upflow Anaerobic Filter), was equipped with the following measurement devices: biogas flow-meter, feed and recycling flow-meters, thermometer Pt-100, biogas analyser (CH4 and CO), Hydrogen analyser and pH-meter. Other parameters such as alkalinity, Chemical Oxygen Demand (COD) and Volatile Fatty Acids (VFA) were determined off-line. All the on-line sensor measurements were monitored, through a PLC (Programmable Logic Controller), which indicated about the plant failures, including the measuring devices (giving messages or alarms to the operator) and provided the set points for the PLC.
The pilot plant was started-up at an initial Organic Loading Rate (OLR) of 2 kg COD/m3.d (Hydraulic Retention Time (HRT) 5 days and 10 kg COD/m3), this value increasing up to 10 kg COD/m3.d by decreasing HRT to 1 day. The behaviour of the bioreactor during start-up and steady state operation was studied. After that, an experiment was performed to analyse the response of the bioreactor to an organic overload. From the results, different variables were evaluated as useful control parameters. Monitoring of CO concentration did not permit the prediction of destabilisation of the bioreactor. However, H2 concentration is quite a sensitive variable, which must be analysed together with other parameters such as methane composition or gas flow-rate. Besides, alkalinity is easy to measure and provides immediate information about the state of the plant, as was shown through the off-line measurements.
Mussels as biomonitors of point and diffuse sources of trace metals in the clyde sea area, Scotland
Authors: Miller B. S. 
Published: May 2018

Following a series of international conferences on pollution of the North Sea, the UK Government committed itself in 1990 to reducing the inputs of certain dangerous substances reaching the aqueous environment from point and diffuse sources. The target was a 50% reduction in loadings over the period 1985-95. Metals loadings from rivers and sewage works to the Clyde Sea Area are presented for the period 1990-97. These are compared to trace metals body burdens in mussels collected from shores throughout the Clyde Sea Area over the period 1980-97.
For most metals, no clear trend either increasing or decreasing was observed in metals loadings from point sources or in mussel body burdens. The exceptions were cadmium, which showed downward trends with time in loadings and in concentrations in Clyde Estuary mussels, and lead, which showed a downward trend in mussel concentrations.
Metals loadings from point sources may have reached baseline levels, below which further reductions will be difficult to achieve. Elevated mussel body burdens of specific metals provided good evidence that some shores are severely affected by point source inputs, others by bulk contamination from far-field point sources, and others by diffuse sources of metals.
Upgrading of an Activated Sludge Plant with Floating Biofilm Carriers at Frantschach Swiecie S.A. to Meet the New Demands of Year 2000
Authors: Hansen Eva , Zadura Leszek , Frankowski Stefan , Wachowicz Marian 
Published: May 2018

Frantschach Swiecie S.A., the largest Pulp & Paper producer in Poland and one of the larger in Europe, chose to upgrade the existing WWTP with a new floating biological bed equipped with an advanced steering system. The discharge from the WWTP will be one of the lowest in Europe, 4 kg COD/tonne produced pulp, and is already below the future goals for the European Union. The new demands have been reached with an advanced steering system controlling three selective biological reactors operating in series and/or parallel. Each biological reactor is operating at specific conditions to decrease selected organic compounds. The new floating biological bed, FlooBed®, is an upgraded activated sludge system with floating carriers covered with a thin biological film. The FlooBed® reactor is a progress from fluidised beds and modified activated sludge plants.
The activated sludge plant as such has not been rebuilt. The improvement of the activated sludge process is that the wastewater now is saturated with oxygen and new micro-organisms are created before the entry to the existing activated sludge plant.
The FlooBed® reactors are installed in a volume that is 50 % of the former activated sludge plant volume and the reduction of COD has increased from 51 to 90 %. The operational costs for the FlooBed® are 17 EUR/tonne reduced COD where 7 EUR is electricity and the remaining part is added chemicals.
Characterization and anaerobic treatment of the sanitary landfill leachate in Istanbul
Authors: Inanc B. , Calli B. , Saatci A. 
Published: May 2018

In this study, characterization and anaerobic treatability of leachate from Komurcuoda Sanitary Landfill located on the Asian part of Istanbul were investigated. Time based fluctuations in characteristics of leachate were monitored for an 8 month period. Samples were taken from a 200 m3 holding tank located at the lowest elevation of the landfill. COD concentrations have ranged between 18800 and 47800 mg/l while BOD5 between 6820 and 38500 mg/L. COD and BOD5 values were higher in summer and lower in winter due to dilution by precipitation. On the other hand, it was quite interesting that such a dilution effect was not observed for ammonia. The highest ammonia concentration, 2690 mg/L was in November 1998.
BOD5/COD ratio was larger than 0.7 for most samples indicating high biodegradability, and acidic phase of decomposition in the landfill.
For anaerobic treatability, three different reactors, namely an upflow anaerobic sludge bed reactor, an anaerobic upflow filter and a hybrid bed reactor, were used. The anaerobic reactors were operated for more than 230 days and were continuing operation when this paper was prepared. Organic loading was increased gradually from 1.3 kgCOD/m3.day to 8.2 kg COD/m3.day while hydraulic retention time was reduced from 2.4 days to 2.0 days. All the reactors showed similar performances against organic loadings with efficiencies between 80% and 90%. However the reactors have experienced high ammonia concentrations several times throughout the experimental period, and showed different inhibition levels. Anaerobic filter was the least affected reactor while UASB was the most. Hybrid bed reactor has exhibited a similar performance to anaerobic filter although not to the same degree.
Anaerobic treatment of landfill leachate by sulfate reduction
Authors: Henry J.G. , Prasad D. 
Published: May 2018

The present study was conducted to investigate the effectiveness of the sulphate-reduction pathway in the anaerobic treatment of landfill leachate. The effects of several COD/SO4 ratios (keeping COD constant) and loadings on anaerobic filter performance were studied and compared with the results from anaerobic filters which followed the methanogenic pathway.
Results indicated that the treatability of leachate by sulphate reducing bacteria (SRB) was dependent upon the leachate strength. With high strength leachate (COD=15000 mg/L) from the Keele Valley Landfill, it was found that at lower COD/SO4 ratios (≤1.6) toxic conditions developed in the system that were more inhibitory to the SRB than to the methane producing bacteria (MPB). As the COD/SO4 ratio increased, methanogenesis predominated. No predominance of SRB occurred at any COD/SO4 ratio with high strength leachate. The highest COD removal achieved was about 70% of which 20% was accomplished by the SRB at a COD/SO4 ratio of 1.6 and an organic loading rate (OLR) of 4 kg COD/m3.d.
With low strength leachate (COD=1500-3300 mg/L) from the Brock West Landfill, and a COD/SO4 ratio &lt;1, SRB became predominant. In these anaerobic filters in which SRB were predominant, the SRB reduced the COD as well as the MPB could. Sulphide inhibition did not take place at any loading in units treating low strength leachate. Consequently, both SRB and MPB should function at COD/SO4 ratios between 1 and 3. About 60% COD removal was achieved at a loading of 2.8 kg COD/m3.d and a COD/SO4 ratio of 1.0. However at a loading of 6 kg COD/m3.d only 27% COD removal was achieved, all of it through the sulphate-reduction pathway. These OLR values are comparable to those applied in systems where methanogenesis was dominant.
It was also observed that once the methanogens were established in the units, it was not possible to displace them completely. However, where methanogenesis had not been previously established, it was found that sulphate-reduction could be the sole pathway for COD removal.
From this study, it can be concluded that there is no advantage to the sulphate-reduction pathway in the anaerobic treatment of landfill leachate. The other options for increasing the loadings, i.e. the use of high surface/volume filter media (to achieve higher biomass concentrations) or high rate systems are likely to be more successful.
The activity of anaerobic biomass in thermophilic and mesophilic digesters at different loading rates
Authors: Zábranská J. , Štěpová J. , Wachtl R. , Jeníček P. , Dohányos M. 
Published: May 2018

The thermophilic anaerobic process brings an acceleration of biochemical reactions and higher efficiency in the degradation of organic matter in comparison with the mesophilic process. The methanogenic activity of the thermophilic and mesophilic digested sludge was examined during the adaptation of full-scale digesters to an increasing temperature from 38 to 55°C.
The results proved a higher activity of the thermophilic sludge after the addition of glucose, acetate and propionate in comparison with the mesophilic sludge; the maximum methane production rates and the methane yield of the raw sludge were always higher under thermophilic conditions; the stability of the degradation process at an increased substrate load was also better. After the adaptation of anaerobic biomass to the temperature of 55°C, the responses of this culture to addition of simple substrates substantially changed, especially in favor of acetate and propionate degradation rates.
An assessment of the toxicity of some pesticides and their metabolites affecting a natural aquatic environment using the Microtox™ system
Authors: Amorós I. , Connon R. , Garelick H. , Alonso J.L. , Carrasco J.M. 
Published: May 2018

The conservation and preservation of aquatic ecosystems is of utmost importance due to the high diversity and density of species and their complex food network. The evaluation of the potential adverse environmental impact caused by pesticides entering water bodies is an important parameter in aquatic toxicity.
The toxicity of the insecticide, Fenitrothion and two of its metabolites, 3-methyl-4 nitrophenol and 3-methyl-4-nitroanisole, and of the herbicides Thiobencarb and Molinate, commonly used in rice fields in Valencia near the protected area of lake Albufera, has been tested by using the Microtox™ system.
The 15 min EC50 values obtained with the marine luminescent bacterium Vibrio fischeri showed that the Thiobencarb was the most toxic of the three tested pesticides with an EC50 value of 0.03 mg/l. The EC50 values of the first two steps of the Fenitrothion hydrolysis indicated that while the first metabolite, 3-methyl-4-nitrophenol, was as toxic as its parent compound, a decreased toxicity was observed for the second metabolite, 3-methyl-4-nitroanisole.
In order to analyze the toxic effects of pesticides in complex mixtures the EC50 values of Fenitrothion, Molinate and Thiobencarb as pure substances and their mixtures were compared. The impact of the pesticides in the natural ecosystem was also studied and a protective effect of lake water was observed.
Defluoridation in drinking waters
Authors: Azbar N. , Türkman A. 
Published: May 2018

Although water supplies containing excessive amount of fluoride are generally very rare worldwide, there are locations in Turkey where drinking water contains very high fluoride concentrations. Especially in the middle and eastern part of Turkey, some mineral and drinking waters contain very high fluoride concentrations. It is a well known fact that drinking water exceeding the critical fluoride concentration (1 mg F−/L) may cause serious dental and skeletal damages.
In this study, various techniques were evaluated to find the most suitable solution for defluoridation for these regions, which have high concentrations of fluoride in their water supplies. For this purpose, various chemical agents including locally produced alumina were investigated. Locally produced alumina gave promising and economically sound results in terms of defluoridation capacity and availability.
Suspended carrier technology allows upgrading high-rate activated sludge plants for nitrogen removal via process intensification
Authors: Münch E.v. , Barr K. , Watts S. , Keller J. 
Published: May 2018

The Oxley Creek wastewater treatment plant is a conventional 185,000 EP BOD removal activated sludge plant that is to be upgraded for nitrogen removal to protect its receiving water bodies, the Brisbane River and Moreton Bay. Suspended carrier technology is one possible way of upgrading this activated sludge wastewater treatment plant for nitrogen removal. Freely moving plastic media is added to the aeration zone, providing a growth platform for nitrifying bacteria and increasing the effective solids residence time (SRT).
This paper presents the results from operating a pilot plant for 7 months at the Oxley Creek WWTP in Brisbane, Australia. Natrix Major 12/12 plastic media, developed by ANOX (Lund, Sweden), was trialed in the pilot plant. The pilot plant was operated with a mixed liquor suspended solids concentration of 1220 mg/L and a total hydraulic residence time of 5.4 hours, similar to the operating conditions in the full-scale Stage 1&2 works at the Oxley Creek WWTP. The plastic carriers were suspended in the last third of the bioreactor volume, which was aerated to a DO setpoint of 4.0 mg/L. The first third of the bioreactor volume was made anoxic and the second third served for carbon removal, being aerated to a DO setpoint of 0.5 mg/L.
The results from the pilot plant indicate that an average effluent total inorganic nitrogen concentration (ammonia-N plus NOx−N) of less than 12 mg/L is possible. However, the effluent ammonia concentrations from the pilot plant showed large weekly fluctuations due to the intermittent operation of the sludge dewatering centrifuge returning significant ammonia loads to the plant on three days of the week. Optimising denitrification was carried out by lowering the DO concentration in the influent and in the carbon removal reactor. The results from the pilot plant study show that the Oxley Creek WWTP could be upgraded for nitrogen removal without additional tankage, using suspended carrier technology.
Total nitrogen removal in two-step biofiltration
Authors: Pujol R. , Tarallo S. 
Published: May 2018

A one-year study was carried out on two semi-industrial submerged up-flow biofilters - a pre-denitrification (pre-DN) step followed by a nitrifying (N) step, designed to treat the primary settled municipal wastewater of a full scale plant for both carbon and nitrogen removal. Performances of the pre-DN step have been investigated showing high removal denitrifying capacities – 1 to 1.2 kg NO3−–N removed per m3 of reactor per day–, obtained with high TSS and carbon loading rates, at a water velocity up to 21.5 m3/ m2.h. The complete treatment plant – primary settlement + pre-DN/N loop – has demonstrated a nitrogen removal efficiency ranging from 70% without any additional carbon, up to 85% with methanol. COD and TSS removal rates were 91% and 97% respectively.
The above results show that two submerged biofilters in series form a treatment line suitable for nitrogen removal. This technical choice leads to very compact full scale plants such as Ahlen WWTP (Germany, 85 000 PE).