bluuebunny/crossref_metadata_2025 huggingface dataset:
Odour measurement and odour policy in Germany
Authors: Frechen F.-B.
Published: May 2018

Odour emissions can cause serious annoyance in the neighborhood of the emissions source. Thus, especially in densely populated areas, odour is a topic since several decades in Germany. Development of measurement possibilities and development of odour policy are connected, because formulation of standards as well as control of compliance with these standards need appropriate measurement methods. This paper gives a glimpse of the development of both aspects and thereafter explains the actual state of them inside Germany. Then some special notes will be presented concerning some special cases as for example waste technology, wastewater treatment technology and application at agriculture.
Hydrogen sulphide dispersion modelling - urban and rural case studies
Authors: Parsons S. A. , Smith N. , Gostelow P. , Wishart J.
Published: May 2018

Sewage treatment works are subject to a range of parameters governing the quality of effluent and sludge produced. An additional product from treatment plants is odorous air. The causes, source, formation and measurement of odour are widely reported and reasonably understood. An important factor in the design and management of works is the prediction of such odours. The importance of this work is explained by the possibility of future legislation controlling odour at wastewater plants. Odour dispersion modelling involves the on-site measurement or prediction of the emission rate of an odorous compound, oftenhydrogen sulphide, and the subsequent prediction of the atmospheric concentrations of that compound downwind of the source. This paper used the USEPA models SCREEN3 and ISCST to determine hydrogen sulphide contour concentrations emitted from unit processes at two different sewage treatment works in the United Kingdom. Results indicated that the first site, locatedin an urban catchment, emitted hydrogen sulphide at varying rates. The predicted downwind concentrations using “urban” dispersion coefficients correlated well with measured concentrations. At the second site, emission rates were less variable. Results from the second site produced the best correlation using “rural” dispersion coefficients. Results from both sites suggest that the definition of the surrounding land use is critical in predicting odour dispersion. The problem of determining land use is highlighted and the importance of correct meteorology is stressed. Both sites were predicted to be capable of producing hydrogen sulphide concentrations at a detectable level outside the site boundary. Odour complaints were therefore anticipated. The operational performance of a unit treatment operation is proposed as a major influence on hydrogen sulphide emission. The idea of a large database of expected emission rates from individual unit treatment processes is proposed as an input for dispersion modelling and as an aid to future design.
Optimization of the Envirochek capsule method and immunomagnetic separation procedure for the detection of low levels of Cryptosporidium in large drinking water samples
Authors: Pezzana A. , Vilaginès Ph. , Bordet F. , Coquard D. , Sarrette B. , Vilaginès R.
Published: May 2018

The method for concentration of Cryptosporidium oocysts in large drinking water samples using the Envirocheck capsule has been optimized for the detection of low levels of oocysts. Elution from the filter by contact time and vortex agitation gave 68% oocyst recovery. Centrifugation (1,250 g; 30 min; 4°C) improved recovery to 94% without morphological damage of the oocysts. Increasing the ratio of magnetic beads to sample volume in the IMS procedure led to 69% efficiency. In these conditions, the overall recovery of the procedure was 49% as assessed with low oocysts spike doses in 100 litres tap water samples. The methodology described allows the detection of 0.1 oocyst per litre when 100 litres samples are processed.
Operational experiences from a sludge recovery plant
Authors: Hansen B. , Karlsson I. , Cassidy S. , Pettersson L.
Published: May 2018

A full-scale sludge recovery pilot plant has been in operation since autumn 1995 at Helsingborg WWTP in Sweden, a facility which treats wastewater from 150,000 p.e. The pilot plant, with a maximum capacity of 500 kg TS/hour, is now redesigned and automated for continuous operation. In this paper the process, operational experiences as well as difficulties and utilisation of the products, will be presented.
Start-up of the Subiaco Enersludge™ plant
Authors: Bridle T. , Molinari L. , Dr Skrypski-Mantele S. , Dr Ye P. , Mills J.
Published: May 2018

The first commercial-scale plant, to convert sewage sludge to oil, using the ENERSLUDGE™ technology, has recently been constructed at the Subiaco Wastewater Treatment Plant (WWTP) in Perth, Western Australia. The plant, designedto process up to 25 dry tonnes per day (tpd) of mixed raw primary and thickened excess activated sludge, comprises numerous unit operations which allows the facility to operate in four distinct modes, namely as a chemical stabilisation plant, an LPG-fired dryer, an autogenous sludge dryer and ultimately as a sludge conversion plant. As of June 1999, the plant is operable in the first three modes of operation. Commissioning of Mode 4, namelysludge conversion to commence in August 1999 and initial results provide confidence in the technology, with the major problems being mechanical in nature. Operating results have indicated sludge quality has a major impact on plant performance. To improve operability, a strainpress has been installed to remove much of the hair and fibre present in the sludge. The plant can now successfully process sludge with between 20 and 50% by weight of thickened excess activated sludge.
Partitioning of Cr, Cu, Pb and Zn in sewage sludge incineration by rotary kiln and fluidized bed furnaces
Authors: Mininni G. , Braguglia C. M. , Marani D.
Published: May 2018

The behaviour of four metals (Cr, Cu, Pb, Zn) during sewage sludge incineration was studied in eight pilot plant tests performed with a rotary kiln (RK) and a fluidised bed (FB) furnace. To simulate sludge co-incineration with hazardous wastes, in three FB tests feed sludge was mixed with chlorinated organic compounds. Chromium and copper showed similar concentrations both in bottom or cyclone ash and in fly ash, even at high chlorine input and high combustion temperature. In contrast, zinc and lead concentrations in fly ash produced in RK tests are one or two orders of magnitude higher than those in bottom ash. However, not even these two metals showed significant enrichment in FB tests carried out at high chlorine input. The predictive capability of a thermodynamic model was checked by comparing predicted metal volatilisation in the combustion chamber with experimental metal enrichment in the fly ash. Large discrepancies were observed in FB tests carried out at high chlorine content, where Pb, Zn, and Cu are predicted to volatilise in great extent, andin RK tests where zinc volatilisation is not predicted. Likely explanations of these discrepancies are the very short solid residence times in the FB furnace (non equilibrium conditions) and the incomplete mixing conditions in the RK furnace (pyrolysis pockets).

From the environmental impact point of view, the pilot tests suggest that sludge incineration with fluidised bed furnace is safer than the one using rotary kiln furnace.
Sewage can make Portland cement: a new technology for ultimate reuse of sewage sludge
Authors: Onaka T.
Published: May 2018

From the viewpoint of environmental and energy problems, it is desirable that the organic and inorganic components of sewage sludge can be reused cost-effectively. A process is described which can meet this need. The process was investigated in a large-scale industrial trial, involving the pelletizing-drying of sewage sludge, combined with burning in a Portland cement kiln. Special attention was paid to product quality; plant safety; simple operation and maintenance; ability to process different sludge and water contents; and low consumption of energy. There were no odour and dust emissions. The study demonstrated that dried sewage sludge pellets could gainfully be used by Portland cement manufacturer.
Sludge disposal: ethics and expediency
Authors: Vesilind P. A.
Published: May 2018

The United State Environmental Protection Agency (U.S. EPA) attempted to set health-based regulations for sludge disposal and used worst-case scenarios to estimate the detrimental health effect. In the absence of adequate information, this exercise led them to err so much on the conservative side that the regulations became unrealistic and would not have been accepted by the public. So the US EPA decided to do what was expedient – to establish regulations that allow most wastewater treatment plants to dispose of their sludges, knowing that these regulations are better than none at all. Such regulatory decision-making has ethical ramifications because it involves distributing costs and benefits between affected citizens. The principle of expediency as articulated by Earle Phelps calls for a regulator to optimize the benefits of health protection while minimizing costs within the constraints of technical feasibility. Phelps' expediency principle, proposed over fifty years ago, is still a useful application of ethics using scientific knowledge to set dynamic and yet enforceable environmental regulations. In the case of sludge disposal, the US EPA made an ethical decision based on the principle of expediency, weighing the moral good of human health protection versus the moral harm of taking wealth by requiring costly wastewater sludge treatment and disposal.
Biosolids management at 18 waste water treatment plants in South Africa - optimisation strategies
Authors: Du Preez L. A. , Van der Merwe W. , Terblanche J. S.
Published: May 2018

When the operation of 18 waste water treatment plants was taken over by ERWAT, improved sludge management was identified as one of the key objectives. After evaluations, operational strategies were formulated and implemented to align biosolids management with international trends as well as South African Guidelines on permissible utilization and disposal of sludge. Improved sludge management includes minimizing intake of heavy metals from industry through cooperation with local municipalities. Beneficial use of sludge from the Olifantsfontein waste water treatment works was increased through establishing a partnership with the local farming community. Rehabilitation of mine dumps was identified as an option for beneficial use of biosolids.
Käppala 2001 – upgrading and expansion of the Käppala Wastewater Treatment Plant: project management
Authors: Bengtsson B. , Palmgren T.
Published: May 2018

Käppala Association has the responsibility to receive and treat wastewater from 11 municipalities situated just north of Stockholm in Sweden. Running a tunnel system, 60 km long, and a treatment plant meet this responsibility. The Association was formed in 1957 and the tunnel system and the Käppala plant were taken into operation in 1969. The plant is situated in Lidingö, northeast of Stockholm. The load will in 1999 correspond to nearly 500,000 p.e.

The plant built in the sixties was running until the 31 March 1998 when a new part was taken into operation. During 1998–1999 the old part will be upgraded and the expanded and upgraded Käppala plant will run under ordinary conditions in the year 2001. The expansion was decided on the basis of improvement on four points namely:

1. Capacity improvement. The design year is 2020 and the estimated load will then correspond to about 700,000 p.e. The design load of the old part is 500,000 p.e.

2. Nitrogen removal. The Swedish Parliament specified in 1990 that at least 50% nitrogen removal should be achieved in the major treatment plants in Sweden.

3. Working conditions. Since the plant is housed in the Käppala rock special demands must be put on the working environment. The demands have increased during the years and the environment had to be improved substantially.

4. Odour. Complaints about odour among neighbors have long been a hot issue in Lidingö and the need for improvement was highly desirable. Also along the tunnel-system there were complaints about odour.

The decision to expand the plant was taken by the owners, nine municipalities in 1993 and the necessary permit from the National Licensing Board for Environment Protection was received in December 1993. The basis for the application to the Licensing Board was a principal design proposal. In this proposal, which was approved by the authorities, the overall treatment process design was determined.
Enhanced stabilisation of sewage sludge through thermal hydrolysis - three years of experience with full scale plant
Authors: Kepp U. , Machenbach I. , Weisz N. , Solheim O. E.
Published: May 2018

The first full-scale plant for sludge disintegration through Cambi thermal hydrolysis was started up in Hamar, Norway at the end of 1995. It is the first plant with a new design where sludge is directly heated by live steam. During the last three years the plant worked with an availability of over 99%. Prior to hydrolysis the sludge is dewatered and the digester is fed with 10-12% DS, saving more than 50% of digester volume compared with a conventional process. The degree of stabilization is around 60% measured as rate COD-conversion into biogas. The stabilised sludge, which is guaranteed free of pathogens, is an attractive product to agriculture and has a high fertilizing effect.
Oxidative treatment of digested sewage sludge with ozone
Authors: Scheminski A. , Krull R. , Hempel D. C.
Published: May 2018

A process to improve anaerobic biodegradation of wastewater treatment sludges is investigated. Recalcitrant organic compounds which are contained in biologically stabilized digested sludge become biodegradable by partial oxidation using ozone and ozone in combination with hydrogen peroxide respectively. By oxidation with ozone, cell walls of microorganisms were destroyed and cytoplasm dissolved in sludge water. Water insoluble substances with high molecular weight were split into smaller, water soluble and biodegradable fragments. Sludge matrix composition regarding protein, lipid and polysaccharide content changed. After ozone consumption of 0.2 gram ozone per gram organic dry matter, the degree of biodegradation of organic matter during the following anaerobic treatment increased to 42%. Due to the oxidizing pretreatment, the dewatering results of the sludges after biological decomposition deteriorated. The polymer demand to reach isoelectric point increased with ozone consumption. Compared to mechanical, thermal and thermochemical disintegration, partial oxidation by ozone achieved highest degrees of organic matter decomposition in the following anaerobic biodegradation.
Acidification of primary sludge to promote increased biological phosphorus elimination and denitrification
Authors: Teichgräber B.
Published: May 2018

The acidification of primary sludge is an important measure to promote increased biological P elimination and denitrification at wastewater treatment plants. In laboratory experiments and at large-scale plants it has been found that the COD in the influent of biological treatment stages can be increased by 10–15% in the form of easily degradable carbonic acids. However, the operation of acidification thickeners leads to odour problems, as well as to considerable problems in terms of safety, in covered tanks.
Pretreatment processes for the recycling and reuse of sewage sludge
Authors: Müller J. A.
Published: May 2018

This paper focuses on mechanical disintegration and will compare its results to thermal and ozone treatment. Several mechanical methods can be used for disintegration of sewage sludge. The methods differ in energy consumption and suitability of the machines for practical application, which is of great influence on the selection of the method. Thermal disintegration processes have a higher energy consumption than mechanical methods, but they can use low cost thermal energy instead of electrical energy. The highest solution of organic components is achieved using ozone treatment. Several reuse options of disintegrated sludge in aerobic and anaerobic processes are explained. An acceleration and enhancement of the anaerobic stabilisation process is observed, especially if excess sludge is used. Mechanical disintegration leads to better results than thermal treatment in the range of 60 to 130°C. For the aerobic process the substitution of external proton donors is of special interest. High denitrification rates can be achieved, if the sludge is adapted to the substrate. Increasing the concentration of nitrogen and phosphorus in the supernatant, in order to recycle these valuable compounds, mechanical disintegration and ozone treatment seem to be more suitable than thermal disintegration.
Phosphorus losses from sewage sludge disposed on a field: evidence from storm event simulations
Authors: Vanden Bossche H. , Audic J. M. , Huyard A. , Gascuel-Odoux C. , Trolard F. , Bourrié G.
Published: May 2018

Sewage sludge is used as fertilizer, owing to its nutrient contents. But little is known about the consequences of sludge disposal on erosion intensity and P losses from soil to runoff. This paper reports on a study of three simulated storm events (40 mm h-1 during 30 min), performed on a field supplied with liquid sludge (23 g L-1 of dry solid). The sludge phosphorus content was 26.5 g kg-1 of dry solid. The runoff and erosion intensity as well as the P losses were monitored during the experiment. The distribution of phosphorus on the soil surface, was investigated after the last simulation. Sludge disposal reduced the total amount of runoff water collected during the experiment from 290 m3 ha−1 to 134 m33 ha−1. It also decreased the quantity of sediment exported from 1200 kg ha−1 to 500 kg ha−1 and the total phosphorus loss from 2.7 kg ha-1 P to 1.4 kg ha−1 P. But, it increased the average concentration of dissolved phosphorus in the overland flow from 0.15 mg L−1 P to 0.57 mg L−1 P. The distribution pattern of P and organic matter, on the soil surface, after the simulations, showed a heterogeneity induced by the runoff processes. This effect is increased by sludge disposal.
Matching odour treatment processes to odour sources
Authors: Jeavons J. , Hodgson P. , Upton J.
Published: May 2018

Severn Trent Water Ltd. has reviewed the performance of its existing odour control technology and conducted trials with new technology. Processes were then selected for a costing exercise for air flow rates and odour concentrations typically found at sewage treatment works. The most cost effective processes for various applications are outlined.
Monitoring the development of anaerobic biofilms using fluorescent in situ hybridization and confocal laser scanning microscopy
Authors: Araujo J. C. , Brucha G. , Campos J. R. , Vazoller R. F.
Published: May 2018

In this study we investigated the development of anaerobic biofilm using a laboratory reactor. We were especially interested in comparing the organization of anaerobic cells (particularly those that are very common in domestic sewage sludge) in a hydrophilic (glass) versus a hydrophobic (polypropylene) surface. Fluorescent in situ hybridization (FISH) with domain and group specific probes directed against 16S ribosomal RNA were used to quantify microbial composition in the biofilm. FISH and confocal laser scanning microscopy (CLSM) were used to elucidate spatial distribution of microbes in the biofilms. Two experiments were carried out, one with pure methanogenic organisms and the other with a microbial anaerobic consortium. The pure methanogen cultures, Methanobacterium formicicum (DSM 1535); Methanosaeta concilli (DSM 3671) and Methanosarcina barkeri (DSM 800) were used to seed the modified Robbins Device (MRD) to allow the development of biofilms on polypropylene and glass surfaces during the 9-days experiment. The results showed that all the three species were colonizing both surfaces after two and nine days of experimental period. In another experiment, with polypropylene coupons only, MRD was seeded with a microbial anaerobic consortium and biofilm formation was studied during 11 days. At the end of this period, the biofilms generated were of uneven thickness with areas of minimal or no surface coverage and areas where the biofilm attained a thickness of 7.0 to 9.0 μm as revealed by CLSM. The results showed that the modified Robbins Device together with the fluorescent in situ hybridization and confocal laser scanning microscopy are suitable tools to study anaerobic biofilm development in different kinds of support materials.
Advanced water treatment as a tool in water scarcity management
Authors: Harremoës P.
Published: May 2018

The water resource is under increasing pressure, both from the increase in population and from the wish to improve the living standards of the individual. Water scarcity is defined as the situation where demand is greater than the resource. Water scarcity has two distinctly different dimensions: water availability and water applicability. The availability is a question of quantitative demand relative to resource. The applicability is a question of quality suitability for the intended use of the water. There is a significant difference in this regard with respect to rural versus urban use of water. In the former case, the water is lost by evaporation and polluted. In the latter case, the water is not lost but heavily polluted. With increasing scarcity, the value of water and the need for controls increase. In this situation, water reuse becomes an option that has been considered exotic until recently. This paper sets the stage with respect to perspective and management options related to implementation of water reuse. Water treatment has to be interpreted as the means by which to purify the water from any degree of impurity to any degree of purity that fits the desired use, including reuse. The historical distinction between processes used in water treatment for water supply versus processes used in water treatment of used water (wastewater) will fade, because it will all be unit processes and operations in combinations to fit the purpose of water use. Water can be purified to any degree of purity - except zero. The challenge of future reuse will be to account for the attitudes related to trace chemicals in water. How precautious is it prudent to be? Risk analysis is no longer an elitist business. It will involve the perception of the public, politicians (and the press).
Determination of nitrification kinetics by the ANITA-DOstat biosensor
Authors: Ficara E. , Rocco A. , Rozzi A.
Published: May 2018

The ANITA biosensor, which measures ammonium oxidation rate by alkaline titration at constant pH, has been recently coupled to open respirometry making it possible to evaluate NH4+ oxidation kinetics by two different and completely independent techniques. This paper describes the use of a new instrument, also derived from the titration biosensor ANITA and named ANITA-DOstat, which incorporates dissolved oxygen (DO) control by H2O2 addition. The peroxide is very rapidly decomposed to H2O2 and O2 by bacterial catalase and supplies oxygen to the mixed liquor. The novelty lies not in the use of H2O2 addition as a source of oxygen for bacterial respiration, but in the measurement of kinetics by DOstat titrimetric respirometry which allows for evaluation of bacterial bio-oxidation parameters directly from the H2O2 flow rate at constant DO concentration. Preliminary results are presented on nitrification kinetics determination, for both ammonium oxidisers (AO) and nitrite oxidisers (NO), carried out by alkaline titration and by the new H2O2 DOstat titrimetric respirometry method.
Application of ultra low pressure reverse osmosis (ULPRO) membrane to water and wastewater
Authors: Ozaki H. , Sharma K. , Saktaywin W. , Wang D. , Yu Y.
Published: May 2018

There is a worldwide grave concern about water pollution control. To mitigate the water scarcity, in arid zones and in the areas with no other sources but brackish water, reverse osmosis technology has played an important role. In an effort to reduce the cost of energy requirement for RO operation, nanofiltration has been developed. Until recently the nanofiltration has been used in water softening and removal of disinfection byproduct (DBO). Use of nanofiltration to desalinate brackish water has been ruled out due to low rejection of salts. The introduction of ultra-low pressure reverse osmosis membrane, categorically a nanofiltration, has widened the horizon of using the nanofiltration in desalinating brackish water as well as surfacewater and wastewater. This development ensures the increase in flux due to improvement in active surface layer formation with the application of very small pressure. The surface charge and hydrophilicity on the surface material of the membrane have shown better flux stability in the high fouling conditions. With the addition of higher flux and higher rejection based on the same chemistry, ULPRO has made another step forward. This introduction will certainly reduce the operation cost and, more importantly, improve the overall reliability of the RO system. Application of nanofiltration is broadened to surface water treatment, wastewaters for nutrient removal and heavy metal rejection from wastewater.
Microbial distribution in UASB granules and its resulting effects
Authors: Fang H. H.
Published: May 2018

Microscopic (SEM and TEM) examinations of biogranules sampled from various UASB (Upflow Anaerobic Sludge Blanket) reactors indicated that microbes are densely packed. The microbial distribution is strongly dependent upon the degradation thermodynamics and kinetics of individual substrates. Biogranules degrading carbohydrates exhibited typically a layered distribution with a surface layer populated with hydrolytic/fermentative acidogens, a mid-layer comprising syntrophic colonies and an interior comprising acetotrophic methanogens. On the other hand, those substrates having a rate-limiting hydrolytic/fermentative step did not exhibit any layered pattern; instead, bacteria were interwined and distributed evenly. These observations have two implications. Biogranules are developed through evolution instead of random aggregation of suspended microbes. Furthermore, biogranules should be less vulnerable to the changes of mixed liquor condition, because the large majority of microbes inside the biogranules are shielded from the hostile mixed liquor environment. The latter is supported by experimental evidence that biogranules are more resistant than suspended sludge to the toxicity of hydrogen sulfide, heavy metals and aromatic pollutants in wastewater.
Bioleaching of copper mining residues by Aspergillus niger
Authors: Mulligan C. N. , Galvez-Cloutier R.
Published: May 2018

A study was initiated to determine the possibility of using the fungus Aspergillus niger for bioleaching and then to identify and evaluate the parameters that affect this process. An oxidized mining residue containing mainly copper (7240 mg/kg residue) was studied. Sucrose and mineral salts medium were initially used to produce citric and gluconic acids by A. niger with various concentrations of residue (1, 5, 7, 10 and 15% w/v). Maximal removal of up to 60% of the copper was obtained for the 5% residue. These experiments showed that the pH decreased to around three within 10 days of incubation. Other substrates were evaluated including molasses, corn cobs and brewery waste. Sucrose gave the best results for copper removal, followed by molasses, corn cobs and brewery waste. Other experiments using ultrasound as a pre-treatment showed that 80% removal of the copper could be obtained for a 5% residue concentration. In conclusion, leaching of copper from a mining residue is technically feasible using A. niger. Further research must be performed to increase the economic feasibility of the process.
Non-biting midges (Diptera; chironomidae) in waste stabilization ponds: an intensifying nuisance in Israel
Authors: Broza M. , Halpern M. , Inbar M.
Published: May 2018

Dan Region Waste Stabilization Ponds (DRWSP) were first operated in 1970 in a rural area south of Tel-Aviv. In subsequent years, with the massive urbanization of central Israel, residence has expanded within 2 km of the ponds. The ponds were found to be a suitable habitat for non-biting midges Chironomus spp. (Diptera; Chironomidae) larvae, giving birth to billions of adult chironomids per day. Since 1998, evening breezes have been carrying large adult swarms into the adjacent town of Rishon Le-Zion where they become a severe nuisance mainly during the spring and midsummer (April–July). Midges may penetrate human mouths, eyes, and ears, restricting evening activity outdoors. In addition, dead midges create aesthetic problems, demanding frequent cleaning. The combination of intensive urbanization near DRWSP and the improved water quality, that optimized the midges developmental conditions in the ponds, may be blamed for the current situation.
Behaviour of the fecal pollution indicators in a soil irrigated with treated wastewater under onsurface and subsurface drip irrigation
Authors: Campos C. , Oron G. , Salgot M. , Gillerman L.
Published: May 2018

A critical objective for any wastewater reuse programme is to minimise health and environmental hazard. When applying wastewater to soil–plant systems, it is to be noted that the passage of water through the soil considerably reduces the number of microorganisms carried by the reclaimed wastewater. Factors that affect survival include number and type of microorganisms, soil organic matter content, temperature, moisture, pH, rainfall, sunlight, protection provided by foliage and antagonism by soil microflora. The purpose of this work was to examine the behaviour of fecal pollution indicators in a soil irrigated with treated wastewater under onsurface and subsurface drip irrigation. The experiment was conducted in a vineyard located at a commercial farm near the City of Arad (Israel). Wastewater and soil samples were monitored during the irrigation period and examined for fecal coliforms, somatic and F+ coliphages and helminth eggs. Physico-chemical parameters were controlled in order to determine their relationship with removal of microorganisms. The results showed high reduction of the concentration of microorganisms when wastewater moves through the soil; and a good correlation between the reduction of fecal pollution indicators and moisture content, organic matter concentration and pH. The application of secondary treated domestic wastewater in this specific soil and under these irrigation systems affect the survival of microorganisms, thus reducing the health and environmental risk.
Biological mechanisms involved in bioflocculation disturbances caused by phenol
Authors: Schwartz-Mittelmann A. , Galil N.I.
Published: May 2018

The research focused on the clarification of the biological mechanisms involved in bioflocculation disturbances caused by the exposure of suspended biomass to phenol shock loading. Contact experiments were performed by exposing activated sludge biomass under non-growth and under growth conditions to various concentrations of phenol. Severe damage to the settling of biosolids could be observed, especially under growth conditions. The following mechanisms were found to be relevant to these disturbances: (1) cellular lysis resulted in the creation of a fraction of small particles (<0.45 μm) which could be considered as mostly cellular debris, due to their sizes and especially to their lack of oxygen uptake; (2) lower hydrophobicity of biosolids surfaces, could be a result of the amphiphatic properties exerted by the phenol molecule, as well as by the cellular components released to the aqueous phase by lysis and by membranal damage; (3) the exposure to phenol caused the unbinding of exocellular biopolymers from biosolids surfaces to the aqueous solution, creating conditions of poor settleability resulting from: (a) bioflocs characterized by low density; (b) dispersion of small biofloc fragments; (c) dispersion of single cells; (4) phenol loading was found able to lower the cellular ATP concentrations and this inhibition of the cellular bioenergetics could also be a factor impairing the boflocculation process.
Interdependent environmental factors controlling nitrification in waters
Authors: Kaplan D. , Wilhelm R. , Abeliovich A.
Published: May 2018

In many areas of the world limited water resources have lead to increased use of recycled water for agricultural and industrial purposes. Prior to releasing reclaimed water to consumers, excessive concentrations of inorganic nitrogenous compounds (ammonium, nitrite and nitrate) must be removed, and the water has to meet sanitary standards. The dynamics and abundance of the different nitrogenous compounds depend on the nitrification process (microbial oxidation of ammonia and nitrite). This is a key process in the nitrogen cycle and the autotrophic nitrifying bacteria catalyzing it are found in soils, sediments, wastewater, freshwater and marine water. Nitrification is a two-step process: first ammonia oxidizers convert ammonia to nitrite and then nitrite oxidizers convert nitrite to nitrate. An efficient nitrification process requires linked balanced activity of the two bacterial groups. Environmental factors that control nitrification affect ammonia and nitrite oxidizers differentially and thus disrupt the linkage between the two steps of the process. The effects of various environmental factors on the two bacterial groups and on the overall nitrification process are discussed. Light was identified to be a major factor inhibiting nitrification in a wastewater reservoir in Israel. Especially, nitrite oxidation was hindered causing the accumulation of nitrite during late spring and summer.
Decomposition of aqueous tetrachloroethylene by Fenton oxidation treatment
Authors: Yoshida M. , Lee B.-D. , Hosomi M.
Published: May 2018

Flask-scale experiments were performed to elucidate the reaction mechanism in which tetrachloroethylene (PCE) in water is decomposed by Fenton oxidation treatment. Concentrations of Cl−, total inorganic carbon, and PCE were measured during a 24-h reaction period in which there occurred a pseudo first-order reaction (k=0.17 h−1) and >95% dechlorination and mineralization. Results indicate that: (i) PCE decomposition due to Fenton oxidation is compensated throughout the experiment by increasing Cl− and CO2, and (ii) mineralization rates derived from the increase in CO2 are nearly the same as dechlorination rates due to the increase in Cl−. GC/MS and GC/ECD analyses of reaction intermediates confirmed the presence of trichloroacetic acid (TCAA) only. That is, organic compounds such as dichloroacetic acid (DCAA), monochloroacetic acid, acetic acid, and formic acid were not detected, having been decomposed by Fenton oxidation although no degradation of TCAA occurred and detected TCAA only explained 1% of decomposed PCE. These findings indicate that dechlorination and mineralization proceed almost simultaneously during PCE decomposition by Fenton oxidation treatment, and not via intermediates such as acetic acid and DCAA.
Future regional climatic changes and their hydrologic, ecological and economic consequences: Northern Caucasus case study
Authors: Menzhulin G.V. , Shkhanukov M.Kh. , Khaydarova V.A. , Kucherova V.A. , Penkova N.V.
Published: May 2018

Methodological approaches are suggested which allow approximate forecasts to be made for regional water resources, withdrawals and consumptive water use for the coming decades. For the purpose of estimation of volumes and effectiveness of water use and availability the techniques by numerical models based on the methodology of economic cybernetics are developed. Examples of estimations are given for Southern Russia especially the Northern Caucasus Region as territory with a typical socio-economic development. These regions are analogues to other marginal areas, most industrialised and populated in the droughty zone of the former Soviet Union.
Dye photo-enhancement of TiO2-photocatalyzed degradation of organic pollutants: the organobromine herbicide bromacil
Authors: Feigelson L. , Muszkat L. , Bir L. , Muszkat K.A.
Published: May 2018

Dye chemicals from the textile industry are a principal source of environmental pollution. The industrial effluents must therefore be treated before their release into the aqueous environment. However, application of conventional biological methods for textile wastewater treatment is limited by unsatisfactory degradation of the refractory dyes and associated chemicals. In the present study a complete degradation of selected azo- and thiazine-dyes has been achieved by TiO2-solar photocatalytic oxidation (SPO). Here the SPO is accompanied by a reaction of dye sensitization. Enhanced degradation of colourless refractory pollutants has been observed in the combined process. The main advantage of the combined approach is the utilization of visible light for assisting the degradation of refractory organic pollutants, not only coloured, but also colourless, which cannot be photosensitized in the visible region. Although very little is known on the subject, the present results demonstrate that the process is promising for the removal of undesirable toxic chemicals from textile industry wastewater. To simulate such conditions we have recently studied the dye photosensitized solar photocatalysis of an uracil derivative. Both UV and visible light are required for enhanced substrate and dye decomposition. Irradiation by UV alone decreased the degradation rate of dye, while visible light alone did not lead to any decomposition at all. It seems that the mechanism of the studied reaction involves a combination of oxidation by hydroxyl radicals, via the hole-electron semiconductor route, with oxidation by singlet oxygen.
The quality and sustainability of the water resources available to Arab villages to the west of the divide in the southern West Bank
Authors: Scarpa D.J.
Published: May 2018

Springs discharging to the Mediterranean Sea drainage systems provide domestic and irrigation water for a group of Palestinian villages in the southern West Bank. Analysis of the water sampled from 70 of these springs at three-monthly intervals from September 1998 to May 1999 determined its suitability for the various uses to which it is put, based on internationally accepted chemical and biological standards. The 1998–99 rainy season was one of the driest on record, causing hardship to those dependent on springs, which diminished in flow or completely dried up. The springs in the area selected have not received the attention their significance deserves. Some of these rural agricultural villages are little removed from subsistence farming. All of these springs are contaminated with bacteria, some dangerously. Chemical pollutants were also observed in many of the springs. There are some rain-fed cisterns, but these too are often contaminated. A few villages receive some water from the network. This study considers the steps which ought to be taken to improve the quality of water, especially drinking water, and suggests possibilities for increasing the amount of water available. It also seeks to determine to what extent these villages can survive as demands for water increase.
Water quality monitoring by Thamnotoxkit F™ including cyanobacterial blooms
Authors: Kozma Törökné A. , László E. , Chorus I. , Fastner J. , Heinze R. , Padisák J. , Barbosa F. A.
Published: May 2018

The Thamnotoxkit F™ was evaluated for detecting cyanobacterial toxins as they may be hazardous to human health if they reach drinking water networks or if people are exposed through recreational activity. This test kit is a 24-hour bioassay using larvae of the freshwater anostracan crustacean Thamnocephalus platyurus hatched from cysts. Nine freeze-dried Microcystis aeruginosa samples from freshwaters of Hungary, Germany and Brazil were tested with the Thamnotox test, rat hepatocyte test, mouse test and analysed for microcystins by high performance liquid chromatography (HPLC). It can be concluded that the Thamnotox test is an alternative simple, cost-effective method that may replace the mouse bioassay used previously for determination of cyanobacterial toxicity.
Catalytic effects of high Mn(IV) concentrations on Mn(II) oxidation
Authors: Aydin S. , Tufekci N. , Arayici S. , Ozturk I.
Published: May 2018

Manganese is one of the common constituents of impounded water and of many well waters. In public supplies, it causes difficulties such as staining of clothes, “black” residues on plumbing fixtures and incrustation of mains. In industrial supplies, it causes severe economic losses through discoloration of products, specks in finished paper, textile, food and beverage products, and reduction of pipeline carrying capacities. Manganese is not known to cause any health problems, and the above conditions are limited to existence of manganese content by 0.05 mg/l in drinking waters, and by 0.1 mg/l or less in industrial waters.

The aim of this study, is the removal of manganese (II) by oxidation with atmospheric oxygen, and to precipitate as MnO2 (s), from the waters with high manganese content. The oxidation of manganese (II) is studied in batch reactors in which the concentrations of manganese (IV) was in the range 0–700 mg/l . A quadratic equation has been given to determine the catalytic reaction rate constant as a function of manganese (IV).
A simple settling model for batch activated sludge process
Authors: Kazmi A.A. , Furumai H.
Published: May 2018

A simple settling model for the batch activated sludge process was proposed that could predict sludge concentration profile as a function of time. The predicted dynamic biomass profile would be used to quantify biological reactions during settling. The model can be applied by giving easily measurable parameters such as initial MLSS concentration, sludge interface variation which characterizes the settling rate, and SVI as an index of biomass settleability. The model describes the sedimentation process of the sludge by linking three concentrations, namely the MLSS on sludge interface (XH), constant MLSS on sediment surface (XC), and the variable MLSS at the bottom (XB). It was tested for wide ranges of activated sludge concentrations (1750 mg/L-4630 mg/L) and SVI (104-265). The model was applied to express MLSS profile for a full scale SBR as well as for 1 and 2 m column settling tests. The simulated MLSS profile by linking three critical concentrations agrees well with the observed data. Mass balance applied at each time step indicated that the deviation was from −2 to +12% of the total initial mass. The stratified MLSS profile simulated from the model was applied to predict denitrification rate during settling.
Application of molecular methods to microbial community analysis of activated sludge
Authors: Onuki M. , Satoh H. , Mino T. , Matsuo T.
Published: May 2018

In the last decade, molecular biology has made significant progress, and innovative molecular methods have become available to analyze microbial community structures. Among them, we applied the FISH (Fluorescent in situ Hybridization) method to analyze activated sludge in wastewater treatment plants (WWTPs). As a result, domain- or division-level community structures in activated sludge were determined successfully without cultivation. We also applied the PCR (polymerase chain reaction) -DGGE (Denaturing Gradient Gel Electrophoresis) method for laboratory nitrifying sludge in order to investigate more detailed microbial community structure. By this method, genus- or species-level community structures were characterized well. This method was also found to be powerful for monitoring the change of microbial community structures. For example, the behavior of Nitrosomonas group was successfully detected in the reactor with nitrification by the PCR-DGGE method.
Identification and characterization of anaerobic mercury-resistant bacteria isolated from mercury-polluted sediment
Authors: Narita M. , Huang C.C. , Koizumi T. , Yamagata T. , Endo G.
Published: May 2018

To develop biotechnology for biological treatment of mercury-contaminated wastes or for bioremediation of mercury-polluted sites, mercury-resistant microorganisms have been isolated and characterized. However, understanding of the mercury resistance mechanism by anaerobic bacteria is lacking. In this study, we tried to isolate anaerobic mercury-resistant bacteria from mercury-polluted sediment in Minamata Bay, Japan. One strain of the bacterial isolates, designated Mersaru, was used for the identification and for the growth capability of mercurials. We also analyzed genetic characteristics of mercury resistance genes (merA and merB gene) from the strain Mersaru. The strain Mersaru, which was isolated from Minamata Bay sediment, was identified as Clostridium butyricum and showed resistance to both inorganic mercury and organomercurials. Furthermore, nucleotide sequence analysis showed that merA and merB genes of the strain Mersaru were identical to those of the B. cereus RC607 an aerobic mercury-resistant bacterium in the nucleotide sequence level. From the pulsed field gel electrophoresis analysis, it is suggest that the mer operon of the strain Mersaru is located on chromosomal DNA.
Degradation of 4-nitrophenol using the Fenton process
Authors: Ma Y.-S. , Huang S.-T. , Lin J.-G.
Published: May 2018

In this study, The Fenton process was applied as a pretreatment method to treat industrial wastewater containing 4-nitrophenol (4-NP). The effect of oxidant dosages on the decomposition of 4-NP and the reaction kinetics were investigated. More than 99% of 4-NP was readily decomposed when the reaction was carried out at oxidant concentrations of 5 mM H2O2 and 5 mg/L Fe2+ for 2 hours. The total nitrogenous compounds and the nitrogen gas evolved, accounted for 88% of the initial nitrogen concentration. However, the maximum DOC removal efficiency was 30.6%; and only 1/3 of 4-NP was mineralized to carbon dioxide by the Fenton process. 4-NP degradation profiles fitted well into a pseudo first-order kinetic equation; degradation rate constant (min-1) of 4-NP increased from 4.3×10-3 to 66.1×10-3 with increasing dosages of H2O2 and Fe2+. In addition, the t value was calculated for studying the significance of simulation by the t-test. It was found that the t value was greater than the value for 99% confidence. This result suggested that the 4-NP decomposition profile could be described by the pseudo first-order kinetic equation. Biodegradability of 4-NP before and after the reaction was 0.018 and 0.594, respectively.
Characteristics of p-chlorophenol degradation by Photo Fenton oxidation
Authors: Yoon J. , Kim S. , Lee D.S. , Huh J.
Published: May 2018

This study investigated the characteristics of Photo Fenton oxidation in comparison with Fenton oxidation in dark environments. The specific objective was to provide an in-depth understanding as to how the presence of UV would effect the reaction and its efficiency as compared to the Dark Fenton Oxidation. All reactions were carried out in batch mode at an initial pH of 3.5, with H2O2 in excess and iron in catalytic concentrations. The medium pressure mercury lamp (320-400 nm) was used as a UV source. The role of UV in Photo Fenton Oxidation of p-chlorophenol was found to be manyfold as compared to Dark Fenton Oxidation. It included the expedition of ferric ion reduction and the photolysis of H2O2, which exerted a direct impact on the p-chlorophenol degradation kinetics by enhancing the production of OH radical. Also included in the role was alteration of the quantity (and potentially quality) of intermediates, which would lead to a change in the decomposition kinetics in an indirect manner. Therefore, it was concluded that the performance of Photo Fenton Oxidation as compared to Dark Fenton Oxidation could vary in complicated ways depending upon the characteristics of target compounds and their intermediates.