bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies of Uptake and Toxic Effects of Cr(VI) on Pistia stratiotes
Authors: Sen A. K. , Mondal N. G. , Mandal S.
Published: May 2018

The uptake of Cr(VI) and toxic effects of the metal on some biochemical parameters in Pistiastratiotes L. were studied. The uptake of Cr(VI) by the plants gradually increased with increase in concentration of Cr(VI) in the culture medium. Maximum accumulation of Cr(VI) was noted within 5 days. Maximum removal (about 90%) of Cr(VI) was recorded below 5 ppm. Accumulation of Cr(VI) occurred mainly in roots. At 5 and 10 ppm, Cr(VI) promoted senescence of Pistia plants by decreasing chlorophylls, protein, RNA, Hill activity and activities of catalase, protease as well as increasing dry weight, free amino acid content, peroxidase activity and ratio of acid to alkaline pyrophosphatase activity over control values. At Cr(VI) concentrations below 5 ppm, these constituents were least affected. So, Pistia plants can be utilised as the scavenger of Cr(VI) from waste water.
Interactions between Phosphate, Nitrate and Organic Substrate in Biological Nutrient Removal Processes
Authors: Gerber A. , Mostert E. S. , Winter C. T. , de Villiers R. H.
Published: May 2018

The response of activated sludge following exposure to various organic compounds is decribed. Batch systems simulating the various stages of biological nutrient removal processes were used to study the dependence of phosphate release, enhanced phosphate uptake and denitrification on the nature and level of organic substrate, and the presence or absence of nitrate. The phenomenon of phosphate release is shown to be controlled primarily by the nature of the substrate rather than the creation of an anaerobic state. Certain short-chain fatty acids or their salts, such as acetate and propionate, induce phosphate release even under anoxic or aerobic conditions but with compounds such as ethanol and glucose release occurs only after the onset of anaerobiosis. Given the necessary conditions, the time course of phosphate concentration in initially anoxic mixtures of phosphate-rich sludge and short-chain fatty acids is shown to proceed in three consecutive stages, comprising primary release, anoxic uptake and secondary release respectively. It is concluded that phosphate uptake and release occur simultaneously in the presence of fatty acids, which also render the best overall phosphate removal during aeration.
The Influence of the Carbon Source on Microbiological Clogging in an Anaerobic Filter
Authors: Ehlinger F. , Audic J. M. , Verrier D. , Faup G. M.
Published: May 2018

Using two different substrates, glucose and a mixture of volatile fatty acids, the influence of the types of bacteria on the appearance of microbiological clogging in anaerobic filters was studied. The clogging was detected by lithium tracings and head-loss profiles. The composition of the biofilm and the electron-microscopy were used to illustrate the phenomenon. The clogging is due to polysaccharides secreted by acidogenic bacteria.
Waterborne Outbreaks in Sweden – Causes and Etiology
Authors: Andersson Y. , Stenström T. A.
Published: May 2018

Thirty-two waterborne outbreaks in Sweden are known during 1975 - 1984, affecting nearly 12000 people. These range from single family outbreaks to community outbreaks affecting up to 3000 people. Microbial agents have been isolated in about 40 % of the outbreaks, the rest are of unknown etiology. Epidemiological investigations have shown that only a fraction of the actual number of cases are initially reported. The real number as judged from epidemiological follow-up investigations was in many instances tenfold higher. In almost all the cases, the cause of the outbreaks are technical deficiencies like back-siphonage of wastewater along drainage pipes, broken sewerage or sudden pollution of raw water intakes coinciding with malfunction of chlorination.
Activated Sludge Settlers: Design and Optimization
Authors: Catunda P F. C. , van Haandel A. C.
Published: May 2018

Activated sludge settlers perform two functions simultaneously: clarification and sludge thickening. Depending on the values of the mixed liquor and return sludge concentrations and on the sludge settling characteristics either one of these functions may limit the solids loading rate that can be applied to the settler, which in turn determines the required settler surface area.

A method is developed to establish which of the two functions is determinant for the maximum solids loading rate in a particular design situation. Expressions are derived to calculate the required settler surface area for clarification and for thickening. These expressions are based on the experimentally verfied supposition that the zone settling velocity decreases exponentially with increasing suspended solids concentration. A graphical method to determine the optimal mixed liquor and return sludge concentrations for minimum construction and operational cost is presented.
An Assessment of a Low-Cost Wastewater Disposal System after Twenty-Five Years of Operation
Authors: Reidy B. L. , Samson G. W.
Published: May 2018

A low-cost wastewater disposal system was commissioned in 1959 to treat domestic and industrial wastewaters generated in the Latrobe River valley in the province of Gippsland, within the State of Victoria, Australia (Figure 1). The Latrobe Valley is the centre for large-scale generation of electricity and for the production of pulp and paper. In addition other industries have utilized the brown coal resource of the region e.g. gasification process and char production. Consequently, industrial wastewaters have been dominant in the disposal system for the past twenty-five years. The mixed industrial-domestic wastewaters were to be transported some eighty kilometres to be treated and disposed of by irrigation to land.

Several important lessons have been learnt during twenty-five years of operating this system.

Firstly the composition of the mixed waste stream has varied significantly with the passage of time and the development of the industrial base in the Valley, so that what was appropriate treatment in 1959 is not necessarily acceptable in 1985.

Secondly the magnitude of adverse environmental impacts engendered by this low-cost disposal procedure was not imagined when the proposal was implemented. As a consequence, clean-up procedures which could remedy the adverse effects of twenty-five years of impact are likely to be costly.

The question then may be asked - when the total costs including rehabilitation are considered, is there really a low-cost solution for environmentally safe disposal of complex wastewater streams?
An Investigation of the Performance of Two Newly Installed Defluoridation Plants in South Africa and Some Factors Affecting Their Performance
Authors: Schoeman J. J. , Leach G. W.
Published: May 2018

Two activated alumina defluoridation plants have recently been installed and commissioned at a mine in South Africa. A reduction in plant capacity was experienced as a result of fouling of the activated alumina by entrapped suspended solids, metal hydroxides, carbonates and adsorbed silicates. It was demonstrated, however, that plant capacity could be restored by using backwashing and air scouring with rinsing repeatedly, using acid treatment periodically for silicate and hardness removal and by performing an interrupted run. Plant performance would also have been improved by the use of smaller sized (0.5 to 1.0 mm) alumina particles. Chemical costs for fluoride removal should vary between 15 and 18c/m3. Periodic cleaning of the fouled alumina, for example every fifth cycle, would add 2c/m3 to production costs.
Rejection of Alkyl Phenols by Reverse Osmosis Membranes
Authors: Frik Schutte C. , Belfort Georges
Published: May 2018

The removal of different alkyl phenols by two commercially available reverse osmosis membranes, one cellulose acetate and one aromatic polyamide both with very high rejection of NaCℓ was investigated. The polyamide membrane rejected phenol very effectively while the cellulose acetate membrane showed virtually no phenol rejection. In order to explain these differences a study was made of the mechanisms of phenol rejection by the two membranes. Transient diffusion tests as well as partitioning tests were conducted in addition to the reverse osmosis experiments. From the results it is concluded that phenol is sorbed in both membranes and that the forces of attraction between phenol and cellulose acetate are relatively weak compared to the attraction between phenol and polyamide resulting in a faster rate of diffusion in cellulose acetate and hence poor rejection.
Development and Optimization of a Process Combination of a Highest-Loaded Activated Sludge Stage and Biologically Intensified Filtration
Authors: Firk W. , Ghandehari N.
Published: May 2018

Conventional sand- and two-layer filtration is frequently put into action for the purpose of advanced wastewater treatment after low-loaded activated sludge systems. However, the effectiveness of this conventional filter concerning the biological content which is difficult to degrade (measured by COD) is extremely low - and the costs too high. In direct comparison, modifying the filters to a biologically intensified system, brings about a substantial increase in efficiency while costing very little more.

The investigations of the authors for the optimization of the whole system, consisting of an activated sludge process and a biologically intensified filter, led to the fact that for the requirements of advanced treatment, the size of the activated sludge stage can be substantially reduced, without the effectiveness of the system as a whole being affected.

In the field of normal requirements (national effluent standards) and comparable low influx concentrations, biologically intensified filtration can be combined with a high-loaded activated sludge process of SLR up to 5 kg BOD5/(kg MLSS.d). The area required for the construction of the system is under 50% compared to the conventional one-stage activated sludge system.

At higher influx concentrations the simultaneous addition of precipitants/flocculants to the high-loaded activated sludge stage, leads to substantial improvement of the effluent of the whole system and simultaneously to a distinct phosphorus elimination. This process modification is greatly advantageous, especially for densely populated lake areas.

The oxygen supply system of the filter has a key function in connection with the influent concentration and the loading of the biological stage.
Improvement of COD Elimination in Activated Sludge Treatment Plant for Pulp and Paper Mill Waste Waters
Authors: Möbius C. H.
Published: May 2018

In recent years, authorities have issued more stringent COD regulations for industrial effluents in addition to BOD limitations. Optimization of operation in the activated sludge treatment plant can be an effective way to meet those regulations without increasing treatment cost. A well dimensioned aerobic or anaerobic plus aerobic treatment plant for pulp or paper mill waste waters is capable of reducing BOD effluent concentrations to values below 25 mg/l. If the aerobic plant is just big enough to meet this limit, COD elimination will be found to be in a certain ratio to BOD elimination, which has become well known in recent years. If this COD elimination is not sufficient to meet official requirements for COD concentration in the effluent, improvement of COD elimination by optimizing the operating conditions of the activated sludge plant may be possible. Lowering BOD sludge loading and increasing hydraulic retention time to more than 8 hours generally are the ways to do this. Concentration of dissolved oxygen has no effect on COD elimination above 1 mg/l. The best COD elimination can be obtained in optimized aeration cascade reactors and two stage aeration reactors.
Removal of Chlorophenols and Chlorolignins from Bleaching Effluent by Combined Chemical and Biological Treatment
Authors: Milstein O. , Haars A. , Majcherczyk A. , Trojanowski J. , Tautz D. , Zanker H. , Hüttermann A.
Published: May 2018

Organic matter from spent bleaching effluents (from chlorination (C) or extraction (E) stages, or a mixture of both) was effectively precipitated as a water insoluble complex with polyethyleneimine (polyimine). Precipitation was performed in a pilot unit operating automatically. The colour, chemical oxygen demand (COD), and adsorbable organic halogens (AOX) were reduced in the C-effluent by up to 92%, 65%, and 84%, respectively. Regarding the E-stage effluent, reduction was up to 76% for colour, 70% for COD, and 73% for AOX. No significant reduction of BOD5 was observed in the supernatant of the treated effluent. Fish toxicity was greatly reduced. Laccase increased the molecular weight of the effluent constituents, thus facilitating subsequent precipitation. After treatment with laccase, the bulk of mono- and dichlorophenol is coprecipitated with the liquors from the C and E bleaching stages. Fungi (representatives of the genera Aspergillus and Penicillium) achieved an appreciable level of degradation of chlorophenols and other chloroorganic compounds from the bleaching effluent.
Effect of Temperature on Anaerobic Digestion of Pulp and Paper Industry Wastewater Sludges
Authors: Puhakka J. A. , Viitasaari M. A. , Latola P. K. , Määttä R. K.
Published: May 2018

Mesophilic and thermophilic digestion of wastewater sludges from the forest industry were studied in semicontinuous flow reactors. Laboratory scale reactors were used for anaerobic treatment studies of a mixture of primary and secondary sludges from a CTMP mill. The VSS reductions in mesophilic and thermophilic digestion of combined CTMP sludge were 41 and 36%, respectively. Specific gas production in the mesophilic process was 0.09 m3/kgVSS added or 0.38 m3/kgVSSreduced. In thermophilic digestion the respective numbers were 0.05 and 0.13. The mesophilic digestion process was stable at an organic loading rate of 2.5 kgVSS/m3d, which represents a 15 days retention time. The supernatant quality of thermophilic digestion was poor (CODsol usually between 3000 and 4000 mg/l) compared with the supernatant of mesophilic digestion (CODsol 1000-2000 mg/l.
Investigations of Chlorinated Thiophenes: A Group of Bioaccumulable Compounds Identified in the Effluents from Kraft Bleaching
Authors: Carlberg G. E. , Johnsen S. , Landmark L. H. , Bengtsson B.-E. , Bergström B. , Skramstad J. , Storflor H.
Published: May 2018

By comparison with six synthesized standards the identity of the following chlorinated thiophenes were established in spent kraft bleach liquors: 2,3,4-trichlorothiophene and 3-formyl and 3-acetyl di- and trichlorothiophene. The synthesized standards were found to be isomers of the thiophenes identified in the effluents. A large number of lipophilic terpene derivatives with from one to four chlorine atoms were also detected.

The synthesized chlorinated thiophenes were found to have partion coefficients (Log Pow) between 3.8 and 5.6. The compounds were found to bioaccumulate in bleak. About one third of the concentrations at the end of the exposure period remained in the fish after an elimination period of 14 days. The compounds were moderately toxic towards the harpacticoid Nitocraspinipes. Three of the compounds showed mutagenic activity.
Organochlorine Compounds in the Environment
Authors: Paasivirta Jaakko
Published: May 2018

Recent pollution by organochlorine compounds (OCs) has been found to cause ecological damage, initially by causing declining populations. Poisoning of animals having high OC levels was often found to be similar to poisoning of man and animals in dioxin accidents. Dioxin toxicity has been shown to occur from structural binding of the toxin to a cytosolic receptor, and this action has been extended to many planar and coplanar aromatic OCs which are released into the environment from pesticide uses, dumping of chlorophenol wastes, chlorobleaching of pulp, chlorodisinfection of water, and combustion of OCs or chloride-containing materials. More efficient combustion has been developed to restrict OC emissions. Recent analyses of wildlife samples have shown that certain planar or coplanar aromatic chlorohydrocarbons and ethers, instead of the notorious polychlorinated dibenzo dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), could be the most important receptor-specific environmental toxins.

Despite the fact that the pollution of the aquatic ecosystem by the forest industry in many areas is decreasing due to improved processes and treatment plants, organochlorine bleaching products still appear to have importance due to harmful discharges, especially since they still cause taste problems in seafood due to the bioaccumulation of chloroanisoles and chloroveratroles.
The Effect of Fluorine on the Precipitation of Hydrous Iron Oxides from Groundwater Using Re-Infiltration
Authors: Vuorinen A. , Lahermo P. , Hatva T.
Published: May 2018

The behaviour of Fe, Si, Cu, Zn and F was studied in a plant constructed for purification of groundwater from excess Fe, Mn and organic matter by aeration and subsequent re-infiltration at Taivassalo, south-western Finland. The aquifer of the groundwater intake comprises the Laitila rapakivi area and the water has a relatively high F content.

The groundwater purification plant consist of two units. In the pre-treatment unit the water was discharged onto a macadam contact filter for aeration, after which it flowed through two clarification basins to the infiltration basin of the re-infiltration unit. Fe oxidized during the treatment and precipitated as hydrous oxides. Precipitates were filtered from water and dried at 20°C, both immediately after sampling and after two year's aging in natural water at 4°C.

To clarify the mode of occurrence of the elements the samples were subjected to extraction by 1 M ammonium acetate (NH4Ac) at pH 7.3 for exchangeable and loosely bound elements, at pH 4.8 for loosely bound and sorbed elements, by 1 M hydroxylammonium chloride plus 2 M acetic acid (HX1 - HAc) at 18°C for reducible loosely bound elements and Fe oxyhydroxides, and by HXl-HAc at 80°C for total Fe oxyhydroxide bound F. The precipitates were extracted with NH4Ac (pH 4.8) and HX1-HAc during different time intervals.

The F content in water decreased along the flow path but increased during the re-infiltration step. The removal of F from water would obviously be more efficient if the plant arrangements like retention time were more suitable for this purpose. F and Si interacted strongly with Fe in the precipitates, preventing their ordering, and F, Si and Fe correlated well with each other. The loosely bound forms of these elements decreased along flow path and increased during aging of the precipitates. F and Cu were strongly, and Zn less strongly sorbed and scavenged by the precipitates. Owing to the relatively low pH of the raw water (5.74) Ca2+and other cations were not sorbed as was observed at higher pH's (over 7) and Cu and Zn were sorbed instead.
Facilitated Degradation
Authors: Lindqvist Roland
Published: May 2018

Dissolved organic macromolecules have been found to facilitate the transport of hydrophobic organic compounds in the soil. The facilitated transport increases the speed with which toxic and carcinogenic compounds reach the ground water drinking supply. The bacterial degradation of hydrophobic pollutants attached to the dissolved organic macromolecules is unknown. A better understanding is crucial for assessing the importance of the facilitated transport concept for drinking water quality.

The degradation of C-14 labelled hexachlorobenzene (HCB) in a saturated soil, with and without 500 mg Blue Dextran/l (BD, model macromolecule) was measured by the amount of radioactive carbon dioxide produced. The soil was contained in stainless steel columns which were purged continuously with sterile air. The lag phase was much shorter in the columns with BD and at the end of the experiment all BD was consumed.

In a current batch study with HCB-adapted bacteria the possibility of differentiating between degradation of HCB free in solution and HCB associated with the macromolecule is examined by evaluating three different mathematical models.

Model 1 assumes only HCB free in solution is degraded, only by bacteria in solution.

Model 2 assumes only HCB associated to BD is degraded, only by associated bacteria.

Model 3 assumes associated HCB is degraded by associated bacteria and HCB free in solution is degraded in solution.
Treatment of Petromeum Refinery Effulents in a Fixed-Film Reactor
Authors: Hamoda M. F. , Al-Haddad A. A.
Published: May 2018

A four-stage fixed-film reactor with 0.5 m3d−1 capacity and surface area-to-volume ratio of 72 was developed in which stationary submerged biofilms are attached to ceramic tiles and kept under diffused aeration. Reactor operation with a synthetic toxic waste and a petroleum refinery effluent was satisfactory.

Organic loading was found to be a better operational or design parameter. An organic loading of 42 g COD m−2d−l or less is recommended to ensure good quality effluent. The reactor coped with organic and hydraulic overloads because of the good oxygen transfer capacity and the considerable quantity of attached biomass attained in the reactor. The majority of COD removal occurred in the first stage which retained the greatest quantity of attached biomass. Staging of the reactor is effective in damping excessive loadings.

Biological treatment of the refinery waste removed up to 80% of COD and produced a good quality effluent but polishing of reactor effluent using alum treatment improved effluent quality for potential reuse.
By-Products from a Petrochemical Effluent Treatment Plant: The Case of Sitel
Authors: Simon Zeno , Baldasso Mario L. , Zoppas Tania R. M.
Published: May 2018

Normal unit operations conducted at SITEL, the integrated wastewater treatment system of South Petrochemical Complex, Triunfo, State of Rio Grande do Sul, Brazil, generate several by-products that must be handled separately: sludges, slurries, scums, garbage, grit, containers, etc. Some are hauled to the Centralized System of Control of Solid Residues (SICECORS); others are disposed of within SITEL battery limits. This paper presents and discusses their origin, production, chemical constitution, final destination and provides a detailed comparison between the main residues. A revision of the current classification criteria is proposed.
Experience of 16 Years' Operation and Maintenance of the Fukashiba Industrial Wastewater Treatment Plant of the Kashima Petrochemical Complex – II. Biodegradability of 37 Organic Substances and 28 Process Wastewaters
Authors: Matsui S. , Okawa Y. , Ota R.
Published: May 2018

Twenty-eight process wastewaters and thirty-seven organic substances identified in the wastewater of the Kashima petrochemical complex were subjected to biodegradability tests. The tests consisted of the activated sludge degradability method and a supplementary test using the respiration meter method. Both tests utilized the activated sludge of the Fukashiba industrial wastewater treatment plant, which was acclimatized to the wastewater and organic substances. The 28 process wastewaters were classified into biodegradable, less biodegradable, and non-biodegradable according to the percentage TOC removal and the BOD5/TOC ratio of the wastewater. The 37 organic substances were also classified into biodegradable, less biodegradable and non-biodegradable according to TOC and CODMn removal. In general, chlorinated compounds, nitro-aromatics and polymerized compounds were difficult to biodegrade. From the biodegradability tests of the factory wastewaters, it was found that the refractory CODMn loads of these factories contributed to the load remaining in the effluent of the wastewater treatment plant. Various improvements were made to reduce the discharge of refractory substances from the factories.
The Development of Assessment Techniques to Evaluate the Biodegradation of Oily Sludge in a Landfarming System
Authors: Casarini D. C. P. , de Macedo R. M. , Cunha R C de A , Mauger J. C. O.
Published: May 2018

A respirometer assay was developed with the intention of defining a standard methodology to identify the major mechanisms related to biodegradation of oily sludge in a landfarming system. The oily sludge is characterized as a biological sludge produced in an activated sludge wastewater treatment plant which treats industrial and domestic wastewater from a petroleum refinery. The effects of soil pH control, nutrient balance, and sludge application rates were investigated. It was concluded that the methodology is acceptable as a procedure to qualify waste for land treatment. The soil with pH control (pH about 7.0) was shown to be more effective in oily sludge biodegradation than without pH control. Under these experimental conditions, the best application rate for the oily sludge on soil was 1% (w/w) of its hydrocarbon content. Soil pH control, sludge nutrient balance, and sludge application rate are all of importance to optimize the system, to avoid leaching, and to protect the groundwater. The landfarming system has been used by several refineries.
Managing Water Quality in Relation to the Petrochemical Industry
Authors: Matthews P. J.
Published: May 2018

The paper reviews the impact of petrochemicals on the aquatic environment from the view point of the water manager. It concentrates on the effects of refinery effluents. Oil products can disrupt the ecology of environmental waters and render the management of sewerage and sewage treatment systems difficult. Water management can utilise different approaches to the avoidance of deleterious effects and that favoured by the UK involves the use of quality objectives. These can be used to calculate acceptable effluent quality limits. Continued achievement of the objectives must rely on satisfactory monitoring and analytical methods. With the international nature of oil pollution, international analytical methods are being introduced.
Experience with a Selector Used for Treatment of Sugar Beet Waste
Authors: Ruider E. , Kroiss H. , von der Emde W.
Published: May 2018

The largest sugar mill in Austria is situated on a small creek (100-200 1/s) and the waste water, which has a flow of up to 45000 m3/d, is treated in a low loaded activated sludge plant with a selector. The installed plant consists of a 6700 m3 capacity primary sedimentation tank, a 400 m3 selector (coarse bubble aeration tank), a main aeration tank of 16000 m3 capacity equipped with 16 mammoth rotors each 9 m long and a final settling tank.

The plant has operated very reliably since it started to run in the campaign of 1984.
Dissolved Oxygen Control in the Activated Sludge Process
Authors: Barnard James L. , Meiring P. G. J.
Published: May 2018

The increased cost of energy and the need for biological removal of plant nutrients resulted in a renewed interest in dissolved oxygen control in the activated sludge process. Back-up systems are required to prevent overaeration during the night which may be detrimental to the nutrient removal process. Full-scale experience with both fine bubble and surface aerators are described.
Improved Oxygen Dissolution Control for Oxygen Activated Sludge
Authors: Clifft R. C. , Garrett M. T.
Published: May 2018

Now that oxygen production facilities can be controlled to match the requirements of the dissolution system, improved oxygen dissolution control can result in significant cost savings for oxygen activated sludge plants. This paper examines the potential cost savings of the vacuum exhaust control (VEC) strategy for the City of Houston, Texas 69th Street Treatment Complex. The VEC strategy involves operating a closed-tank reactor slightly below atmospheric pressure and using an exhaust apparatus to remove gas from the last stage of the reactor. Computer simulations for one carbonaceous reactor at the 69th Street Complex are presented for the VEC and conventional control strategies. At 80% of design loading the VEC strategy was found to provide an oxygen utilization efficiency of 94.9% as compared to 77.0% for the conventional control method. At design capacity the oxygen utilization efficiency for VEC and conventional control was found to be 92.3% and 79.5%, respectively. Based on the expected turn-down capability of Houston's oxygen production faciilities, the simulations indicate that the VEC strategy will more than double the possible cost savings of the conventional control method.
Thickening of Surplus Sludge by Means of Flotation
Authors: Preiss W.
Published: May 2018

In order to save operating costs for sludge treatment it is necessary to thicken the surplus sludge as far as possible. That is the reason why at the Emscher mouth treatment plant one existing circular thickener has been converted to a flotation plant. The experience gained so far shows good results of the achieved dry solids concentration but also a lot of technical problems.
Odour Emissions and Odour Control at Wastewater Treatment Plants in West Germany
Authors: Frechen F. B.
Published: May 2018

Odour emissions caused by wastewater treatment plants can bring serious annoyance to the plant's staff and local residents. A measurement technique is required that corresponds to the human impression of smell. Thus, olfactometry was used to determine the odour strength. Many facts contribute to the formation and release of odorous emissions. Surveys as well as measurement programs indicate that the sludge part of a wastewater treatment plant is the most critical part. Different types of waste air treatment plants are in use in West Germany. Regarding the total amount of waste air to be deodorized, chemical scrubbers play the major role today. Looking at the numbers of plants, bio-filters are most common. Biological waste air treatment systems are of increasing importance in West Germany.
Rotterdam-Dokhaven Sewage Treatment Plant; A Large Sewage Treatment Plant in the Midst of a Developing Residential Quarter
Authors: Meijer Hugo A.
Published: May 2018

The Rotterdam-Dokhaven Sewage Treatment Plant (STP) is operational since July 1987.With a biological capacity of 470,000 population equivalents it is not nearly the largest STP in the Netherlands. But an underground sewage treatment plant with a city park on top, in the midst of a developing residential quarter is very unusual. The designers had to be innovative in order to meet the severe environmental requirements based on the Nuisance Act. The plant is characterised by extensive ventilation facilities, a two-step activated sludge process: A-B system, application of PVC-lining on large-scale to prevent concrete corrosion, a separate sludge handling site where the washed ventilation air is expelled by a chimney stack.
Multiple Toxicity and Accumulation of Heavy Metals in Two Bivalve Mollusc Species
Authors: Kaitala S.
Published: May 2018

Single and combined additions of copper (0.2 mg/l), zinc (0.4 mg/l) and manganese (2 mg/l) were used to examine the multiple accumulation and toxicity of these metals in sessile blue mussel Mytilus edulis L. and burrowing clam Macoma baltica (L.) in a 23-factorial experiment. Concentrations of metals were analysed with atom absorption spectrometry. The accumulation of metals and their toxicity were determined by regression analyses.

The presence of copper ions stimulated the accumulation of zinc and manganese in mussels so that the concentration of manganese was 100 % and zinc 25 % higher than without copper additions. In accumulation of manganese and copper in clams, other metals did not have any effect and zinc did not accumulate at all. The values of lethality (LC50) were 127/µg Cu/l for mussels in 8 days and 54 µg Cu/l for clams in 10 days.
Toxic Chemical Pollution of the St. Lawrence River (Canada) and its Upper Estuary
Authors: Allan R. J.
Published: May 2018

Decline of the Beluga whale population in the upper estuary of the St. Lawrence River may be related to the high content of toxic metals and organic chemicals in their tissues. For three years, the National Water Research Institute has conducted research cruises of the St. Lawrence River to identify the major toxic chemical pollutants in the river and to determine their transport to, and fate in, the upper estuary. The impact of toxic chemicals in the estuarine zone is tied not only to their fate in the increasing salinity and turbidity zone of the upper estuary but to their source, transport mechanisms, and fate in the upstream river.
Sorption Behaviour of Waste-Generated Trace Metals in Estuarine Waters
Authors: Glegg G. A. , Titley J. G. , Millward G. E. , Glasson D. R. , Morris A. W.
Published: May 2018

Samples of suspended particles have been collected from the turbidity maximum region of the Tamar Estuary, S.W. England. Specific surface areas and porosities of the particles were determined by a BET nitrogen adsorption technique. The role of surface coatings of organic matter and Fe and Mn oxides was examined. The data show that the specific surface area was highest at the turbidity maximum and was associated with high Fe/Mn ratios. The characterised particles were then used in time-dependent adsorption-desorption experiments, with waters from the metal-rich Carnon River, S.W. England. The rates and extents of the sorption processes were interpreted in terms of a two-stage reaction which was related to the microstructures of the particles. Kinetic analyses of the desorption profiles gave rate constants which are of significance in the prediction of the fate of toxic metal wastes discharged into estuaries.
The Effects of Development of a Tidal Barrage Upon the Water and Sediment Quality of the Mersey Estuary (U.K.) and its Biota
Authors: Hockin D. C. , Parker D. M.
Published: May 2018

The prime constraint upon the development of a tidal power generating barrage is the use of the Mersey estuary as a waste disposal facility. Historical disposal of persistent wastes continues to cause environmnetal problems, even though modern practices have resulted in a reduced pollution load. Mercury and lead have the greatest environmental significance, although with reference to barrage operation the nutrient status and increased transmission of light through less turbid water will be of equal or greater importance. A constraint upon the recreational use of the impounded water body will be the unacceptable numbers of faecal bacteria.

A criterion for the design of the barrage should be the maximisation of the volume of water entering on each tidal cycle to disperse nutrients and pollutants and import as much oxygen as possible. This will minimise the increase of retention time and reduce the probability of methylation of mercury within the sediment. Additionally it will have implications for the feeding behaviour of the internationally important wildfowl populations.
Petroleum-Like Off-Flavour in Seasoned Herring Roe
Authors: Sato T. , Matsuoka N. , Sugihara H. , Akazawa H. , Motohiro T.
Published: May 2018

A petroleum-like off-flavour found in seasoned herring roe was implicated as styrene by head-space gas chromatography and gas chromatography-mass spectrometry. The styrene was not detected in the plastic packaging film or in samples of fresh and normal seasoned roe. However, one strain of yeast was isolated from an off-flavoured sample of seasoned herring roe. The styrene was subsequently produced in a test seasoning solution into which the yeast isolate had been inoculated and incubated at 25°C. The yeast isolate was identified as TorulopsisCandida (Saito) Lodder 1922.
Biochemistry of Biogenic Off-Flavour Compounds in Surface Waters
Authors: Jüttner F.
Published: May 2018

Nor-carotenoids, unsaturated hydrocarbons, aldehydes, ketones and alcohols, thio compounds, terpenoids, phenols and aromatic hydrocarbons are important biogenic odour compounds frequently found in freshwater. Results of biochemical studies of members of the above list are presented.
Effect of Environmental Factors on Geosmin Production by Fischerella Muscicola
Authors: Wu J. T. , Jüttner F.
Published: May 2018

The production of geosmin by axenic cultures of Fischerellamuscicola (ATCC 29114) was analysed by gas chromatography and mass spectrometry. A methanol based extraction procedure preceding closed loop stripping was successfully applied for quantitative analysis. The major part of geosmin produced by this cyanobacterium was bound in the cells. Less than 1% of the total geosmin was released. The content of geosmin in cells varied with culture conditions. Higher concentrations (based on protein amount) were observed in lag phase cultures and under anaerobic growth conditions. The synthesis of geosmin was temperature dependent showing minimum percentage concentrations at the optimum growth temperature (30°C). Heat shock treatment at 47°C did not affect the subsequent production of geosmin.
Overview of Technology for Controlling Off-Flavors in Drinking Water
Authors: McGuire Michael J. , Gaston John M.
Published: May 2018

Several reviews of treatment methodologies for control of off-flavors in drinking water have recently been published. This paper builds on these reviews, adding new information developed by the Metropolitan Water District of Southern California and other research groups.

The most important tool in any program to control off-flavors is a reliable, reproducible, easy-to-use analytical method. It is difficult to control off-flavor problems unless the off-flavor compound is identified or a sensory technique is used. From a cost perspective, most off-flavors can be best controlled at the source. Treatment methods, particularly those utilizing chemicals and activated carbon, are effective but expensive, and they can lead to secondary problems that are more objectionable than the off-flavor.
Reduction of Musty Odor Substances in Drinking Water – A Pilot Plant Study
Authors: Terashima K.
Published: May 2018

The reduction of the musty odor substances 2-methylisoborneo1 (MIB) and geosmin, was investigated using a 60m3/day scale pilot plant. The ozone dose rate of 2-5mg/l was sufficient for the reduction of MIB and geosmin, and their reduction rates were between 75-100%. Two rapid sand filtrates, one pre-chlorinated and the other not pre-chlorinated,were introduced to the granular activated carbon (GAC) filters. Depending on which influent was used, the reduction rates were different and the GAC filter which filtered the water without pre-chlorination maintained its effectiveness in removing MIB and geosmin longer than the other. On the basis of these results, a 2000m3/day scale demonstration plant was constructed. The results of 1 year operation demonstrated the effectiveness of the method in removing musty odor substances from a large city water supply.
Legionnaires Diseases and the Water Environment in Israel
Authors: Shuval Hillel I. , Fattal Badri , Bercovier Hillel
Published: May 2018

Using systematically evaluated methods, 39 strains of Leqipnella were isolated from 302 samples of water from surface sources, fishponds, cooling systems and wastewater stabilization ponds. Most isolations were made during the warm irrigation season (May to October). Leqionella pneumophila was the most frequent species isolated. Evidence that Leqionella can infect and survive for long periods, at low temperatures, in a natural aquatic protozoan (Acanthamoeba palestinensis), may provide a possible explanation for the over-wintering mechanism during which period the organisms are rarely identified in free form in water samples. Antibody levels to Legionnaires disease bacteria were determined on a total of 2,410 blood samples drawn from 1,335 individuals residing in rural agricultural cooperative villages (kibbutzim). The population studied included irrigation and other water contact workers exposed to aerosolized water from sprinkler irrigation systems using clean water, wastewater and non–water contact individuals as controls. Water contact workers carried antibodies to Leqionella pneumophila seven times more frequently than the non–water contact control group (2.8% vs 0.4%). There was no difference between those exposed to sprinkler irrigation with clean water or wastewater effluent. It is concluded from this study that under the conditions in Israel where Leqionella spp. are ubiquitos in irrigation water sources, workers exposed to aerosols from sprinkler irrigation have a high occupational risk of infection with Legionnaire disease bacteria.
Mechanisms of Bacterial Survival in Chlorinated Drinking Water
Authors: LeChevallier Mark W. , Cawthon Cheryl D. , Lee Ramon G.
Published: May 2018

Experiments showed that attachment of bacteria to surfaces provided the greatest increase in disinfection resistance. Attachment of high nutrient grown, unencapsulated, Klebsiellapneumoniae to glass microscope slides afforded the microorganisms as much as a 150 fold increase in disinfection resistance. Other mechanisms which increased disinfection resistance included: the age of the biofilm, bacterial encapsulation and previous growth conditions (e.g. growth medium, and growth temperature). These factors increased chlorine resistance from two to ten fold. The choice of disinfectant residual was shown to influence the type of resistance mechanism observed. Disinfection by free chlorine was affected by surfaces, age of the biofilm, encapsulation and nutrient effects. Disinfection by monochloramine, however, was only affected by surfaces. Importantly, the research showed that these resistance mechanisms were multiplicative (e.g. the resistance provided by one mechanism could be multiplied by the resistance provided by a second). These results provide important insights to understand the survival of bacteria in chlorinated drinking water supplies.
Binding of Metal Ions by Extracellular Polymers of Biofilm Bacteria
Authors: Geesey G. G. , Jang L. , Jolley J. G. , Hankins M. R. , Iwaoka T. , Griffiths P. R.
Published: May 2018

Exopolymers which anchor sessile bacteria to metallic surfaces exhibit the capacity to bind copper ions with high affinity. Ionized carboxyl groups on the polymers appear to participate in cupric ion binding. Formation of complexes between the polymers and cupric ions results in the release of protons from the polymer molecule. Attenuated total reflectance Fourier transform infrared spectroscopy showed that polymers composed of acidic polysaccharides promote ionization and deterioration of metallic copper surfaces. X-ray photoelectron spectroscopy studies revealed that the ionic state of the surface-derived copper varied depending on the type of acidic polysaccharide that was in contact with the surface. The results suggest that exopolymers elaborated by adherent bacteria can enhance corrosion of the surfaces with which they are associated.
Recombinant DNA Plasmid Transmission to Indigenous Organisms during Waste Treatment
Authors: Gealt M. A.
Published: May 2018

The release of genetically engineered microorganisms into the environment will occur because of its importance to industrial and agricultural progress. Since organisms designed for release can be modified to survive only the time necessary for their function, the greatest potential for environmental damage depends upon the capability for mobilization of the genetically engineered DNA sequences (GEDS). Mobilization of GEDS to indigenous wastewater organisms by the process of bacterial conjugation has been demonstrated. This gene transfer, which will occur in a laboratory-scale waste treatment facility (~20 L capacity), depends on the presence of bacteria containing conjugative plasmids, many of which are indigenous to waste water. Sensitive detection of GEDS transfer requires the use of DNA-DNA hybridization. Environmental conditions do affect the frequency of conjugal gene transfer.
Determination of Active Biomass
Authors: Jensen B. K. , Eriksen T. , Jørgensen P. E.
Published: May 2018

Reliable techniques for determination of active biomass are fundamental in both wastewater treatment and ground water contaminant predicting and modelling. Different approaches to determine the biomass were tested in wastewater and ground water. To evaluate the reliability of the obtained results they were compared to corresponding microbial activity parameters. The wastewater studies involved growth cultures prepared by inoculatiny a synthetic medium with wastewater bacteria. In the maximum growth phase of these growth cultures a high correlation was found between ATP, OD, O2 consumption and FDA hydrolysis. The latter, however, overestimated the biomass seriously when applied to untreated wastewater samples. In ground water AODC, ATP, diluted and undiluted plate counts were compared to Vmax values for acetate, glucose and naphthalene. Plate counts and especially ATP content showed fairly good correlation with microbial activity. Thus in conclusion ATP is considered to be superior to the other biomass parameters tested as a general applicable biomass parameter in wastewater and ground water.
Hepatitis a Virus Levels in Shellfish Exposed in a Natural Marine Environment to the Effluent from a Treated Sewage Outfall
Authors: Pietri Ch , Hugues B. , Crance J. M. , Puel D. , Cini C. , Deloince R.
Published: May 2018

Hepatitis A virus (HAV) contamination studies and cell-culturable virus determination were undertaken on oysters (Crassostrea angulata) and mussels (Mytilus edulis) kept for six months in the sea near the outfall of a sewage treatment plant. Shellfish and seawater samples were collected on 11 occasions at roughly 15-day intervals during this period. A radioimmunoassay revealed HAV contamination indices (P/N ≥ 2.1) in 3 oyster and 6 mussel samples and 1 sea-water sample. When a radiocompetition test was run on these samples, however, specificity was noted in one mussel sample only (P/N = 2.4). Immune electron microscopy showed that HAV particles were present in three effluent samples. Although a frequent demonstration at sometimes high concentrations (326.0 MPNCU/100 ml) in the effluent was observed, no cell-culturable virus were detected in both the shellfish and the seawater. Adenovirus alone were detected in one mussel sample, but not in the effluent. Complementary studies are now being conducted on all samples with an RIA HAV contamination index of P/N ≥ 2.1. The results of this investigation of viral contamination in a natural marine environment and our HAV detection assays underscore the difficulty of determining the true extent of these phenomena.
Effects of Seawater Contamination Level and Exposure Period on the Bacterial and Viral Accumulation and Elimination Processes by Mytilus edulis
Authors: Mesquita M. M. F.
Published: May 2018

A study was designed in an attempt to explain the effects of seawater contamination level and shellfish exposure period on depuration efficiency of the common mussel (Mytilus edulis). Bacterial indicators (E. coli; group D faecal streptococci) and coliphage, cultured in vitro and present in settled sewage, were used as contaminants. Mussels were exposed to low levels (102-103 CFU and PFU/100 ml) of seawater contamination for 24 hours and to high levels (104-106 CFU and PFU/100 ml) for 30 minutes. Both types of contaminants, under the same conditions gave rise to similar depuration patterns. Low titers accumulated over an extended period appear to cause prolonged retention of a portion of the phage, independently of mussel activity as measured by bacterial elimination. Exposure to high titers for a short period, on the other hand determines more rapid phage elimination but only down to a certain level. A percentage of bacteriophages is always retained in shellfish tissues after 48h depuration. These findings indicate that procedures currently in use for depuration of commercial bivalve shellfish, based on E. coli removal within 48 hours, are ineffective in completely removing bacterial viruses and probably also viruses of public health importance from such shellfish.