bluuebunny/crossref_metadata_2025_split huggingface dataset:
Status of construction and operation of large wastewater treatment plants in South Korea
Authors: Kim I.S. , Ryu J.Y. , Lee J.J. 
Published: May 2018

The history of wastewater treatment in Korea began in 1976 with construction of Chongke sewage treatment plant in the city of Seoul. At present, there are 48 large municipal sewage treatment plants for 42 cities with a total treatment capacity of 7,841,000 m3/d. This indicates that the population receiving sewage treatment is 42% of the total national population. The government is planning to extend the population receiving wastewater treatment to 73% by the year 1997. It turned out that activated sludge processes are the most popular type (39 out of 48 plants) for the treatment of municipal wastewater.
The present lawful effluent criteria for BOD, COD, and SS from large municipal wastewater treatment plant are changing from 30 mg/l, 50 mg/l, and 70 mg/l, to 20 mg/l, 40 mg/l, and 20 mg/l, respectively, by the year 1996. Regulation of the total concentrations of nitrogen and phosphorus are also added as 60 mg/l and 8 mg/l, respectively. The enactment to control the nutrient concentrations in the lake and pond is inevitable for the protection of drinking water in South Korea.
Effects of pH and alkalinity on sulfur-denitrification in a biological granular filter
Authors: Furumai Hiroaki , Tagui Hideki , Fujita Kenji 
Published: May 2018

Two laboratory-scale biological filters were operated to investigate the effects of alkalinity and pH on removal of nitrate and nitrite in sulfur denitrification filter processes. The concentration of sodium bicarbonate in the feed media was changed from 120 to 240 mg/l during about 3 months in a filter (Run A). The other filter was initially fed with 300 mg/l and then with 240 mg/l (Run B). The performance of the filter was monitored by measuring pH, nitrate, nitrite, sulfate, alkalinity, and thiosulfate.
Nitrate concentration in effluent rapidly decreased to lower levels within several days for both filters after inoculation of enrichment culture of sulfur denitrifiers. However there was a large difference in removal of nitrite. When rapid removal of nitrate took place, nitrite accumulation was observed and remained while the bicarbonate concentration was 120 and 150 mg/l. On the other hand the nitrite accumulation disappeared when more bicarbonate (240 and 300 mg/l) was supplied. The experimental results indicated that the nitrite accumulation was closely related to pH condition and alkalinity level in the filter. The stable data of effluent water quality for 5 cases were collected and the relationship discussed between nitrite concentration and pH in effluents. The relationship indicated a strong pH dependency on nitrite accumulation below pH of 7.4. The pH condition around 7 is not so inhibitory to biological activity. Therefore, the pH within the biofilm would be low enough to suppress the nitrite reduction by sulfur denitrifiers, while the pH in effluent was not in the inhibitory range. It was recommended to keep the pH higher than 7.4 to prevent nitrite accumulation in the sulfur denitrification filter.
Primary sludge hydrolysis for biological nutrient removal
Authors: Hatziconstantinou G. J. , Yannakopoulos P. , Andreadakis A. 
Published: May 2018

Primary sludge hydrolysis can enrich primary effluent with the soluble organics which in turn can be a valuable carbon source to subsequent nutrient removal processes. By controlling hydraulic retention time and temperature it is possible to confine the anaerobic digestion of the primary sludge to the acidogenic and acetogenic phase (hydrolysis/fermentation process), and take advantage of the soluble organics produced.
This paper presents the results of a research involving bench and pilot scale experiments related to primary sludge hydrolysis. The pilot scale sedimentation tank (4.10 m in diameter, 3.20 m in depth) operated over an expended period of 21 months as a conventional clarifier and following this as a fermentor unit employing sludge recirculation. Parallel to the pilot scale experiments, several batch and continuous flow bench scale experiments were conducted in order to determine the factors controlling the production of soluble organics and the effect of the latter on the denitrification process.
The conclusions drawn were that a) a soluble COD production of the order of 5-6% in terms of sludge TCOD can be expected in a batch fermentor operating with HRT≅2days at T≤ 20°C, b) in a continuous flow fermentor, combinations of T&gt;20°C and SRT&gt;2 should be applied in order to achieve a production of the order of 10%, c) significant soluble carbon production can be achieved in primary sedimentation tanks (over 30% in terms of influent SCOD) when relatively increased SRTs (4 to 5 days) in combination with sludge recirculation are employed, under T&gt;22°C, and d) increased denitrification performance of the order of 9 mgNOx/g MLSS.hr, can be achieved with hydrolysate as a carbon source.
Sediment pore water toxicity testing
Authors: Heida Henk , van der Oost Ron 
Published: May 2018

The toxicity of the pore water from the sediments of nine fresh water systems in and around Amsterdam City was studied with the aid of four acute toxicity tests. Based on preliminary chemical analysis, the sediments of three of the tested systems had to be considered strongly contaminated, according to the quality standards derived from the Dutch Law on Soil Pollution Control. In addition, the acute toxicity of groundwater from a heavily contaminated industrial building site was also examined. The following toxicity tests were used.
1. Microtox bioluminescence assay, or Microtox test. This test is based on the inhibition of bioluminescence of Photobacterium phosphoreum; 2. Rotoxkit F, based on the LC50 of Brachionus calyciflorus; 3. Thamnotoxkit F, based on the LC50 of Thamnocephalus plaxyurus; 4. Toxichromotest, based on the inhibition of β-galactosidase formation in Escherichia coli. The objective of the study was to test the feasibility of the toxicity tests as a tool for the risk evaluation of contaminated sites, both in water and on land. The results indicated that the sediments of three of the eight sites studied could be classified as toxic and one site even as very toxic. The outcome of the toxicity testing confirmed the results of the chemical analysis for only one site. It appeared that the Microtox and the Thamnotoxkit F tests were the most sensitive acute toxicity tests.
It could be concluded that the resolution of the toxicity tests scrutinized was insufficient to reliably discriminate the environmental quality of the sediments at the locations studied. The bioassays, however, are useful in determining remediation priorities of contaminated sites.
Control of nitrification efficiency in a new biofilm reactor
Authors: Lazarova V. , Nogueira R. , Manem J. , Melo L. 
Published: May 2018

The study of the nitrification capacity of a new gas-lift circulating bed reactor (CBR) carried out with laboratory and industrial scale prototypes, showed a high nitrification rate (1.2-2 kgN m−3 d−1) without any nitrite accumulation. A good nitrification performance 0.5-0.6 kgN m−3 d−1 was maintained even when the CODs/N-NH4 ratio was increased up to 1.8-3.4 (laboratory CBR) and 4-10 (industrial prototype). The comparison of the apparent and intrinsic kinetics indicates that the CBR ensures high specific nitrification rates close to the maximum value. These results indicate an effective control of the attached biomass growth and activity in this type of bioreactor.
The intrinsic kinetics and diffusion limitations were studied by respirometric tests. It was demonstrated that apparent kinetics are zero-order for bulk concentrations of ammonia above 2 mgN l−1 and half-order for lower substrate concentrations. The diffusivity values calculated using the half-order diffusion-reaction model are in the range of 1.09 × 10−9 to 1.58 × 10−9 m2 s−1 for ammonia nitrogen and of 1.1 × 10−9 to 1.37 × 10−9 m2 s−1 for nitrite within the range of temperature studied (16-28°C). The application of the diffusion-reaction model requires a very precise determination of the biofilm thickness or density. In the case of biofilms developed in heterogeneous granular surfaces, new methods have to be developed for the best estimation of the biofilm density and active cells distribution.
In conclusion it can be stated that this new three-phase bioreactor ensures a high nitrification rate and enhanced process stability through an effective biofilm control. The CBR is a good tool for more fundamental studies of biofilm kinetics and activity thanks to the homogeneous distribution of the fixed biomass in the reactor.
How to evaluate photochemical methods for water treatment
Authors: Braun André M. , Oliveros E. 
Published: May 2018

Photochemical advanced oxidation processes (AOPs) generally imply generation of hydroxyl radicals which are initiating the oxidative degradation by well defined reactions (hydrogen abstraction, addition and electron transfer) with available organic substrates. This limitation of the scope of applications may be avoided in implementing combinations of different photochemical and/or thermal processes. A simple evaluation of photochemical AOPs is based on the absorption spectrum of the oxidant to be added and on the spectral distribution of the emission of commercially available light sources. Dominating light absorption, in particular in the UV-C spectral domain, by the solutes of the aqueous system to be treated may lead to exclude some of the degradation processes, as excitation of the oxidant and, consequently, production of the initiator become inefficient with increasing inner filter effects.
The evaluation of photochemical AOPs in terms of volume independent rates is convenient and highly advocated, but such comparisons should only be made for processes applied to a restricted number of model substrates which are to be degraded in optimized equipment. Taking into account the volume independent rates determined in the range of realistic pollutant concentrations, the number of m3 of contaminated water of known pollutant nature and concentration to be treated per unit of time, the list of a commercially available light sources and their geometry, a final selection of the degradation process or of a combination of processes may be made, and the total electrical energy required and the number of photochemical reactors to be built may be calculated.
Effect of particle concentration on the entire cycle of filtration
Authors: Prasanthi H. , Vigneswaran S. , Dharmappa H. B. 
Published: May 2018

Influent particle concentration is one of the physical parameters that influence the overall performance of a deep bed filter. Natural waters with varying turbidity have varying effect on filtration. Experimental and theoretical studies on the effect of concentration on clean bed filter efficiency and ripening stage efficiency have been reported in the literature. However, a comprehensive study on the effect of influent concentration on the transient stage of filtration is not documented. In addition, it is not understood in what units the concentration should be expressed in the mathematical models: the mass, number or surface area of the particles?
In this present study, submicron polystyrene latex beads of sizes 0.46 μm and 0.825 μm were used to study the effect of concentration on the entire cycle of filtration. Experiments were carried out at constant mass, number and surface area as influent concentrations in order to observe the variation in filtration of the two sizes of particle.
At constant mass concentrations, the initial removal was found to be higher for smaller particles (0.46 μm) (in the submicron range); but when the number or surface area of particles was considered, it was found to be higher for larger particles (0.825 μm). The transient stage removal was found to increase with an increase in particle size, either with constant mass, number or surface area as an influent concentration. The Vigneswaran and Chang (1986) model was used to quantify the results. The model parameters estimated using the experimental results are useful in quantifying and understanding the performance of the filter.
Exploring zero discharge potentials for the sustainability of a bottle washing plant
Authors: Visvanathan C. , Hufemia Anna Marie M. 
Published: May 2018

The beverage industry which requires large amounts of good quality water in their processes is a major contributor to the problem of excessive pumping from existing aquifers in Thailand. In view of a government restriction on groundwater withdrawal, an overall water management plan was drawn for the sustainability of a softdrink plant in Bangkok which depends solely on a deepwell source for its water needs. Technologies that can recover water for reuse, minimize raw water input and consequently lead to zero discharge were identified.
The overall water balance drawn for this plant revealed that 76% of the raw water consumed daily ends up in the biological wastewater treatment plant (WWTP). A large portion (40%) of this wastewater is generated from the bottle-washing units. By employing microfiltration for polishing of the WWTP effluent, the plant can recover process water for reuse such that, groundwater input is reduced by 40% and liquid discharged to the receiving water by 56%.
There are two proposed strategies for recovering rinse water from the bottle-washing units. A microfiltration-reverse osmosis system will purify the rinse water for reuse in the bottle washing process, thereby reducing raw water consumption further to 58% and the liquid discharge by 81.5%. On the other hand, a dual filter media-ion exchange system can reduce raw water input to 57% and the liquid discharge by 80.5%.
Micropollutants: a bottleneck in sustainable wastewater treatment
Authors: Janssens I. , Tanghe T. , Verstraete W. 
Published: May 2018

Every year a variety of xenobiotic chemicals as pesticides, dyes,… are introduced on a very large scale. The majority of these compounds have a rather poor biodegradability. Hence, fresh water resources become more and more contaminated with micro-quantities of these man-made pollutants. Moreover, some of these obscure pollutants may have the undesirable capability of having oestrogenic activity on various high forms of life.
This paper deals with the problems of micropollutants in drinking water production and wastewater treatment. The biocatalytic properties of microorganisms can be limiting for several reasons such as lower threshold values for metabolism, insufficient free energy change or inadequate metabolic knowledge base in the microbial cell or community.
The limiting biodegradative capacity of natural microbial associations necessitates the development of more integrated water treatment and management. Research is necessary on two levels i.e. the search for biotechnological processes able to remove such chemicals through engineering of pathways and microbial associations, and the need for reliable biosensors able to generate information on residual microorganics. Trends such as improved biocatalysis and accurate process control are of major significance. However, a clear-cut scientific and political endorsement of the necessity to use reclaimed wastewater is of prime importance to evolve towards sustainable water treatment and management.
Thermal inactivation of plant seeds in sewage sludge
Authors: Baier Urs 
Published: May 2018

Seeds of Tomato (Lycopersicon lycopersicum) and Millet (Digitaria sanguinalis) were exposed to temperatures from 60°C to 70°C for 20 to 75 minutes. The influence of aeration as well as heat protection by sludge solids was investigated in laboratory scale and in full scale sludge hygienisation.
Thermal inactivation of Millet was achieved at temperatures of 65°C where 1 - 5% of the seeds survived an exposure of 60 minutes. Lower temperatures showed little effect on Millet. At 60°C only 1 - 10% inactivation was found after 70 minutes. Complete inactivation could be achieved at 70°C and above with exposition periods of 20 minutes.
Tomato seeds showed a higher resistance to heat inactivation at low temperatures. Temperatures of 60 - 65°C were not sufficient to inactivate the seeds. An exposition of tomato seeds to 65°C for 60 minutes still resulted in a survival of &gt; 20% of the initial seed concentration. Complete inactivation was found at 70°C and higher with exposition periods of 20 minutes.
No difference of heat inactivation was found between static and aerated sludge. The protective action of sludge solids was found to be present but negligible for both species.
Today's sludge hygienisation technology will significantly reduce Millet and Tomato seeds in sludge and eliminate or reduce the risk of contamination of agricultural areas. Thermal pasteurisation processes show a higher seed destruction potential for Tomato and Millet than aerobic - thermophilic pretreatment.
Micropollutant removal with saturated biological activated carbon (BAC) in ozonation–BAC process
Authors: Woo Hang Kim , Nishijima Wataru , Baes Aloysius U. , Okada Mitsumasa 
Published: May 2018

The objective of this study is to evaluate the adsorption capacity of BAC saturated with natural organic matter (NOM) for micropollutant removal which intermittently enter into water sources and to compare this to sand filtration that has no adsorbability but has biodegradability.
The removal of intermittently applied micropollutants was examined with two BAC and sand filters. Two BAC filters which have been operated for 6 and 20 months and a sand filter being used for 6 months for the treatment of reservoir water were used in this experiment. EBCT of these BAC and sand filter were 15 minutes. Bromophenol (highly adsorbable but refractory) and phenol (adsorbable and biodegradable) were used instead of targeted micropollutants. Bromophenol and phenol of about 200 μg·l−1 were applied for 24 hours.
The BAC 1, which was used for 20 months had already lost its adsorbability because it was saturated with NOM. BAC 2 filter which was used for 6 months had small adsorption capacity for NOM. As a result, either BAC 2 or BAC 1 removed bromophenol (160 μg·l−1) completely for 24 hours spike, but sand filter did not removed at all. Bromophenol can be removed only by adsorption, therefore bromophenol might be removed through adsorption by BAC. On the other hand, phenol (220 μg·l−1) whose adsorbability is lower than bromophenol, was removed completely by both BAC 1 and BAC 2.
These results indicate that micropollutants with similar adsorbability as that of phenol and bromophenol can be removed by BAC even after a long period of operation and saturation with NOM.
Full scale experiences with anaerobic pre-treatment of wastewater in the food and beverage industry in Germany
Authors: Austermann-Haun Ute , Seyfried Carl Franz , Rosenwinkel Karl-Heinz 
Published: May 2018

In Germany, there are currently 106 full-scale anaerobic treatment plants treating industrial wastewater. This paper describes the operational experiences of several industries (beet sugar, starch, pectin, brewery, distillery, vegetable) which undertake anaerobic wastewater treatment, with particular emphasis on specific wastewater problems and their solutions. Also presented are experiences of the handling of high nitrate concentrations, with the treatment of mixtures of industrial wastewater from different origins, with the chance to prevent the emergence of lime, magnesium ammonium phosphate (MAP) or aluminium precipitation.
This paper deals with the first municipal wastewater treatment plant combined with a separate anaerobic stage to treat a wastewater mixture of several small factories. One particular asset of this plant is the construction of the acidification tank: using the “teapot effect” to enrich the solid material in the centre of the bottom, the solids can be taken from the bottom of the tank and pumped to the municipal sludge digester.
ASBR treatment of low strength industrial wastewater at psychrophilic temperatures
Authors: Banik Gouranga C. , Dague Richard R. 
Published: May 2018

Anaerobic treatment of dilute wastewater was studied using three laboratory-scale anaerobic sequencing batch reactors (ASBR), each with an active volume of six (6) liters. The reactors were fed a synthetic substrate made from non-fat dry milk supplemented with nutrients and trace metals. The COD and BOD5 of the feed was 600 mg/l and 285 mg/l, respectively. Steady-state performance data were collected at reaction temperatures of 25, 20, 17.5, 15, 12.5, 10, 7.5 and 5°C over a period of two years. Hydraulic retention times (HRT) were maintained at 24, 16, 12, 8 and 6 hours.
Results showed that the ASBR process was capable of achieving in excess of 90% soluble COD and BOD5 removal at temperatures of 25°C and 20°C at all HRTs. At the low temperature of 5°C and the six hour HRT, soluble COD and BOD5 removals were 62% and 75%, respectively. At the intermediate temperatures from 20°C down to 5°C and HRTs between 24 and 6 hours, removal of soluble organics ranged between 62 and 90 % for COD and 75 and 90 % for BOD5. In all cases, SRT were high enough to maintain good performance. Substrate utilization rates and half-velocity constants were also determined at all temperatures. The temperature correction coefficient was found to be 1.08 in the temperature range from 25°C to 7.5°C which follows the Q10 or Van't Hoff's rule.
A VFA measuring biosensor based on nitrate reduction
Authors: Rozzi A. , Massone A. , Antonelli M. 
Published: May 2018

A modified version of a biosensor (DENICON) used to measure nitrates in wastewaters is presented which allows for the determination of VFA concentration as readily biodegradable COD (rbCOD). A sample of the digested effluent is mixed to denitrifying microorganisms in excess of nitrates. As a consequence, a fraction of NO3, proportional to the biodegradable organic carbon, is reduced and may be measured by titration.
The concentration of rbCOD is then derived from the consumption of nitrates as Biodegrable Nitrate Demand (BND). Taking into account that the prevailing fraction of rbCOD in digested anaerobic liquors is made of VFA, this paper investigates the possibility of measuring VFA concentration with the proposed biosensor. Extensive tests have been carried out on a laboratory instrument, using acetate, butyrate and propionate as model compounds.
A satisfactory correlation (R2 &gt; 0.95) between organic carbon and reduced nitrate has been found for the three substrates. Mixtures of acids, especially acetic + propionic have also been tested because this association is the one often found when unstable conditions arise in a digester. It has been observed that the reaction rate increases with respect to acetic acid only when a solution of acetic + propionic acids is denitrified. This effect might allow for a qualitative evaluation of incoming instability.
The instrument can be easily automated and might allow a VFA determination every 20-40 minutes, which is sufficient for most anaerobic applications.