bluuebunny/crossref_metadata_2025 huggingface dataset:
Sedimentation and Digestion on Pond Bottoms – An Attempt to Establish a Short-Term Material Balance
Authors: Iwema A. , Carré J. , Minot D.
Published: May 2018

Sedimentation and digestion have been measured in situ on the bottom of the first (facultative) and the last (maturation) pond of a wastewater stabilization pond system during six periods of one week. Calculated dry solids balances of the ponds bottoms showed that most of the collected solids would have an endogenous origin. Identification of the collected solids by digestion in the laboratory and supplemental in situ measurements in winter, when gas production was low, allowed the conclusion that the collected solids actually were fairly stabilized bottom sediments which are resuspended by the vigorous gas production. The establishment of a short term sedimentation-digestion balance appears to be a practical impossibility on an actively fermenting pond bottom.
The Attenuation of Underground Water Contamination in a Vinasse Clay-Lined Pond
Authors: Büchler P. M.
Published: May 2018

Vinasse, the liquid residue from sugar cane alcohol distillation, is a major industrial pollutant in developing countries. The use of ethanol as an alternative automotive fuel in Brazil led to the construction of large number of stabilization ponds for the treatment of this material prior to river disposal. But, because of the infiltration of this high BOD residue into the groundwater, the water for human consumption has been highly contaminated. The objective of this work is to study a Brazilian clay which can be used both as an impermeable layer and also adsorb the organic components of vinasse. The results show that both the organic components of vinasse and the vinasse itself are adsorbed by the tetramethy1ammonium (TMA) derivative of a Brazilian sodium bentonite. Similar experiments performed with Wyoming bentonite show that the Brazilian clay is less effective than the American one because of its lower content of the clay mineral smectite. A computer simulation shows that the clay liners do not have to be replaced before one year of operation. This is very convenient because the alcohol industry works for 8 months approximately. Therefore when the distillery is not in operation the clay liner can be replaced.
An Alternative Approach to the Design of Waste Stabilization Ponds
Authors: James A.
Published: May 2018

Waste stabilization ponds are frequently used for reducing the bacterial concentration of wastewaters. An examination of their performance suggests that they are inefficient in removal due to a combination of mixing and the presence of organic compounds which reduce die-off rates.

An alternative approach to design is suggested which emphasises organic removal by nethane production followed by light-induced die-off in an alqal free aerobic pond.
High-Rate Algal Ponds: Treatment of Wastewaters and Protein Production: IV – Chemical Composition of Biomass Produced from Swine Wastes
Authors: Rodrigues A. M. , Santos Oliveira J. F.
Published: May 2018

Swine wastes from swine breeding installations were treated in a pilot system of high rate algal ponds, and the Albazod biomass produced was harvested by autoflocculation and centrifugation. The chemical composition of Albazod biomass was determined in order to evaluate the potential of Albazod for utilization as a protein supplement to animal feed. The most important component in the Albazod biomass was crude protein and it varies according to detention time (there is an increase of crude protein when the detention time decreases). Besides the high protein content (for 3 days of detention time we have obtained 41.46% of dry matter for crude protein), the Albazod biomass is rich in minerals, which will enhance its potential as a favourable ingredient for animal feed.
High-Rate Oxidation Ponds: The Israeli Experience
Authors: Shelef G. , Azov Y.
Published: May 2018

The use of high rate oxidation ponds as means for wastewater reclamation and algal biomass production was extensively studied in Israel. The work started from laboratory scale facilities through outdoor miniponds, pilot plant ponds, field scale ponds and a full scale pond. The research involved optimal operational design of high rate oxidation ponds for various locations and constraints, harvesting of the algal biomass and feeding and toxicological studies of the biomass produced. We have found that the system is reliable and efficient as biological wastewater treatment system and could be very valuable if operated according to environmental and climatic constraints of the given area it is designed for.
BOD Removal in Floating Aquatic Macrophyte-Based Wastewater Treatment Systems
Authors: DeBusk T. A. , Reddy K. R.
Published: May 2018

Floating macrophytes cultured in ponds used for secondary wastewater treatment (BOD5 removal) apparently serve two functions: they provide a substrate for bacterial attachment, and their vascular lacunae act as a conduit for the transport of O2 from the atmosphere to the wastewater. In the present study, floating macrophyte systems containing pennywort (Hydrocotyle umbellata) were found to be 10% more effective (on an annual average) at removing wastewater carbon (BOD5) than those containing the more productive water hyacinth (Elchhomla crassipes). This enhancement in BOD5 removal is thought to be due to pennywort's superior O2 transport capability. In a separate six month long study, plant harvesting was found to have no effect on BOD5 removal in a water hyacinth-based treatment system. These data demonstrate that operational strategies used in floating macrophyte-based nutrient removal systems (i.e., frequent harvest of highly productive plants) are inappropriate for those systems utilized for carbon removal.
Removal of Heavy Metals and Sewage Sludge Using the Mud Snail, Cipangopaludina chinensis malle at a REEVE, in Paddy Fields as Artificial Wetlands
Authors: Kurihara Y. , Suzuki T.
Published: May 2018

The effects of the application of reed-sewage sludge compost on the heavy metal incorporation and the growth of young snails born from the adult mud snails, Cipanqopaludina chinensis malleata REEVE, put into submerged paddy soil were investigated. The biomass and growth of the snails in paddy soil with compost were superior to those in soil without compost. The Zn and Cu concentrations in the flesh portion of snails were extremely high as compared with those in the paddy soil surrounding the snails. This may be because snails ingest sewage sludge which is a main organic component of the composts and sewage sludge usually contains large amounts of Zn and Cu, suggesting that this type of snail may be useful in eliminating sewage sludge and Zn and Cu in paddy soil when composted sewage sludge has been applied.
Environmental Impact Assessment of the Discharge of the Effluent from the Faro Waste Stabilization Ponds into the Ria Formosa, Algarve, Portugal
Authors: Pereira Maria Amélia S. , Machado Luís
Published: May 2018

This paper intends to present the main problems studied in the environmental impact assessment of the discharge of the tertiary effluent from a stabilisation pond system to be built for the city of Faro (Algarve) into Ria Formosa, a shallow coastal water body of high ecological, economic and touristic value.

The environmental assessment emphasized the analysis of the impacts that may affect the shellfish beds as well as the flora and fauna, which are mainly the decrease of salinity, the increase of nutrients content and the entry of pathogens.

Despite the impossibility of quantitative assessment, the study concluded that the effects of the variation of salinity and nutrients content will not be very significant. However, the pathogens are likely to contaminate the shellfish bads.

Recommendations are presented including construction and operation of a suitable treatment plant, tight sanitary control of the shellfish before human coneumption and monitoring of the future situation.
Ultraviolet Radiation and Sedimentation of Wastewater Lagoon Effluents
Authors: Adams V. D. , Nieminska E. C. , Borup M. B.
Published: May 2018

A process consisting of ultraviolet radiation followed by sedimentation was used to remove suspended solids from a wastewater lagoon effluent. An average of 33 percent of the suspended solids, 45 percent of the volatile suspended solids, and 54 percent of the BOD5 were removed by this process. The process also produced a microbiologically acceptable effluent by removing 66 percent of the total coliform organisms, 78 percent of the fecal coliforms and 49 percent of the fecal streptococci organisms.
A Study of Upgrading Waste Stabilization Ponds
Authors: Thomas P. R. , Phelps H. O.
Published: May 2018

A study was carried out in one of the two facultative stabilization ponds operating in parallel and receiving domestic sewage in excess of their capacities. Effluent quality from the pond was monitored in terms of the parameters total suspended solids, biochemical oxygen demand, pH, dissolved oxygen and faecal coliform bacteria before and after the introduction of water hyacinths. No significant improvement in effluent quality was observed after the introduction of the water hyacinths. High loading on the pond did not permit to upgrade the effluent quality to acceptable standards by the use of water hyacinths. Although the research is continuing some results and recommendations are given.
The Role of the Operation Regime in Wastewater Treatment with Duckweed
Authors: Oron Gideon , de-Vegt Andre , Porath Dan
Published: May 2018

The results of outdoor experiments with Lemnaqibba (a duckweed species) grown in mini-ponds proved to be highly competitive in comparison with other existing secondary treatment methods. The treated wastewater is at an acceptable level and can be reused for agricultural irrigation. The duckweed biomass, with a crude protein content of over 30% of dry weight, may be used as a protein rich alternative fodder. The ease of duckweed harvesting makes the potential treatment system even more economically attractive.

Operational regime was controlled by the retention time and wastes depth. Retention time was in the range of 3 to 10 days, while the depths examined were 20 cm and 30 cm. The results indicate that shortening the retention time was associated with increase in protein content and did not affect the yield very much. The duckweed yield (dry basis) in the deep ponds (30 cm) was very similar to the 20 cm ponds, viz. around 14 g /m2 per day.
Evaluation of Effectiveness of Two-Phase Anaerobic Digestion Process Degrading Complex Substrate
Authors: Hanaki Keisuke , Matsuo Tomonori , Nagase Michihiko , Tabata Yoshihisa
Published: May 2018

The effectiveness of two-phase anaerobic digestion in degrading complex substrates was studied by using a continuous acidogenic reactor and batch experiments. When 4,600 mg COD/l of milk consisting of carbohydrates, proteins and lipids, was fed to the acidogenic reactor, carbohydrates were easily converted to acids although protein degradation was insufficient and lipids were not degraded. The condition which gave greater than 95% carbohydrate degradation was a pH of not less than 4.5 at a constant HRT of 18 hours, and HRT longer than 6 hours at a constant pH of 6.0. Low pH or short HRT within the optimal range brought about the production of more n-butyrate instead of propionate. Degradation of egg albumin in the two-phase system required a longer HRT (about 5 days) than the ordinary acidogenic reactor. Batch experiments using the mixed liquor from the acidogenic reactor suggest that phase separation is not very effective for the degradation of carbohydrates and proteins, but it can prevent the inhibition caused by lipids.
Biological Treatment for Low-Activity Nuclear Wastewaters
Authors: Ramadori R. , Fenoglio F. , Pozzi L.
Published: May 2018

Safety problems loom so large for the nuclear industry that provision must always be made in treatment of liquid wastes for their recycling to the production process. In this regard, a wastewater treatment consisting mainly of ammonia stripping, biological denitrification and chemical precipitation, looks very promising.

With reference to the biological stage, this paper sets out the results of bench-scale tests performed to evaluate dimensioning parameters for the denitrification process.

The tetrahydrofurfury1 alcohol, the major organic compound in the wastewater, was used as electron-donor substance. The procedure adopted for full-scale plant design and the preliminary results obtained using it, are also presented.
The Fight against Industrial and Urban Pollution in the Artois - Picardie Basin
Authors: Raak Yvon
Published: May 2018

The Artois-Picardie Water Basin is one of the six french water basins whose limits were defined by the 1964 Law on Water. The Water Basin Agency is a public body created to fight against water pollution and to manage water resources; it collects fees from those who pollute and from those who use ground and surface waters and the funds collected are redistributed to industries and local communities that construct sewage networks and purification plants. Thanks to the financial and technical attack launched by the Agency, good results have been achieved. In the field of industry, organic pollution discharged has been reduced to a third with considerable success in several sectors: discharged pollution reduced by 80% in vegetable canning; by 70% in paper plants; by 85% in sugar plants; by 75% in wool-washing plants. The percentage of eliminated pollution coming from communities has progressed from 15% to 35%.
Photocatalysed Oxidation of Toxic Organics
Authors: Brett Borup M. , Joe Middlebrooks E.
Published: May 2018

The feasibility of treating water contaminated by two toxic organic compounds with an ultraviolet light catalyzed oxidation process using hydrogen peroxide as an oxidant is investigated. In this process hydrogen peroxide is decomposed by ultraviolet radiation producing hydroxyl radicals. The hydroxyl radicals will then oxidize organic compounds via a complex chain of radical reactions. Tests showed that this photooxidation process could successfully remove isophorone and dimethyl phthalate from contaminated waters. A reaction rate expression which adequately describes the process was developed. The reaction rate was found to be first order with respect to hydrogen peroxide concentration, zero order with respect to organic concentration and a function of ultraviolet radiation intensity. The reaction did not exhibit autocatalytic characteristics.
Behaviour of Alkylphenol Polyethoxylate Surfactants and of Nitrilotriacetate in Sewage Treatment
Authors: Giger W. , Ahel M. , Koch M. , Laubscher H. U. , Schaffner C. , Schneider J.
Published: May 2018

Effluents and sludges from several municipal sewage treatment plants in Switzerland were analyzed for nonylphenol polyethoxylates (NPnEO, n=3-20), nonylphenol mono- and diethoxylate (NPlEO, NP2EO), corresponding nonylphenoxy carboxylic acids (NP1EC, NP2EC) and nonylphenol (NP). These chemicals derive from nonionic surfactants of the NPnEO-type, and specific analitical techniques were used to study their behaviour during mechanical-biological sewage and subsequent sludge treatment. The parent NPnEO-surfactants, with concentrations in raw and mechanically treated sewage from 400-2200 mg/m3, were relatively efficiently removed by the activated sludge treatment. The abundances of the different metabolites varied depending on treatment conditions. The refractory nature of NPl/2EO, NP and NPl/2EC was recognized. Both biotransformations and physico-chemical processes determine the behaviour and fate of nonylphenolic substances in sewage treatment.

Nitrilotriacetate (NTA) was found in primary effluents at concentrations between 430 and 1390 mg/m3. The various treatment plants showed different removal efficiencies for NTA depending on the operating conditions. Activated sludge treatment with low sludge loading rates and nitrifying conditions removed NTA with efficiencies between 95 and 99%. High sludge loading caused a decrease in NTA removal efficiencies from 70% to 39%.
Application of Batch Kinetic Data to the Sizing of Continuous-Flow Activated Sludge Reactors
Authors: van Niekerk André , Jenkins David , Richard M. G.
Published: May 2018

The removal of substrates from wastewaters by activated sludge is commonly expressed in terms of a collective substrate parameter such as COD, BOD5 or TOC. Several different linear and non-linear rate expressions are employed to describe complex substrate removal in the literature. The indiscriminate application of batch substrate uptake rates to the analysis or design of continuous-flow reactors can introduce errors. These potential errors have particular significance in the design of aerobic selectors used to control low F/M bulking.
Dimensioning of Combined Sewer System Detention Basins by Long Term Simulation of Storm Water Runoff
Authors: Sieker F. , Durchschlag A.
Published: May 2018

At present, dimensioning of combined sewer detention basins in Germany is based actually on the rational formula and on the idea of the existence of the so-called “first flush”. New measurements and recent investigations have led to the questioning of this dimensioning procedure.

An alternative developed in this paper is based on the application a storm-water-runoff-model (hydrological and/or hydrodynamic) in each special case. Input to the model is a period of at least one decade of continuous rainfall data (long term simulation). The sanitary waste water component is superimposed to the simulated runoff-hydrograph. The first flush-effect is neglected. The dimensioning of a detention basin is based on the determination of several quantities such as number, duration, peak discharge and volume of overflow events in relation to the total water detention volume of the system. The decision on final dimensioning has to be made with respect to the characteristics of the receiving water.
Low-Cost Wastewater Treatment with the Use of an Intrachannel Clarifier in Oxidation Ditches
Authors: Vélez O. R. , Foil J.
Published: May 2018

The oxidation ditches developed by Pasveer of Holland and Muskat in Germany have been used in small communities for many years as a cost effective secondary treatment. Generally designed and operated as part of an extended aeration system, these plants provide from 18 to 30 hours of hydraulic detention time, followed by a 3 to 6 hours settling period in a secondary clari-fier, with 100 per cent of settled solids return to the aeration tank. Because of these design criteria, the oxidation ditches were not widely used in large populations as the aeration system normally used required a relatively low water depth to be efficient -a fact that meant extensive land areas. Recent innovations in the clarification and aeration systems have rendered this treatment attractive again for communities of all sizes. The use of an upflow intrachannel clarifier, in particular, eliminates the need for a separate secondary clarifier, and return sludge pumping and piping. In addition, an innovative diffused aeration system permits the use of channels with a greater water depth, which not only optimizes process as an oxidation ditch but also makes it remarkably competitive in respect to conventional biological treatment systems. This paper deals with this innovative oxidation ditch system, analyzing its conceptual design considerations and economic aspects, and commenting upon its first application in Argentina using low-cost construction technology.
Computer Aided Control of Nitrogen Removal in Small Activated Sludge Wastewater Treatment Plants
Authors: Bahre G.
Published: May 2018

Extended aeration plants achieve almost complete nitrification, due to their mean solids retention time of more than two weeks. Intelligent control of nitrification and denitrification processes is called for, due to high energy-costs for additional oxygenation, uncontrolled denitrification processes in the final settling tanks (which impair the effluent quality) and lastly, high effluent nitrogen concentrations. Long experience is available from the application of an on-line nitrate monitor; interpretation of this gives detailed information about nitrification and denitrification processes and kinetics under real operating conditions, depending on temperature, MLSS, BOD and total nitrogen mass flow rates. The poor availability and reliability of the nitrate monitor as a control element led to the development of computer aided control of nitrogen removal processes. A common computer system has been completed with electronic filters, A/D converters and relay interfaces to control the functions of a new fine bubble diffusor system and three air blowers. The software is able to calculate the length of aerobic and anoxic intervals in order to realize a saw-tooth like graph of NOx concentration under various conditions. It also surveys the DO level during aeration periods.
Study of a Non-Conventional Aeration System
Authors: Raschid-Sally L. , Roustan M. , Roques H. , Faup G. M.
Published: May 2018

A non-conventional aeration system for oxidation ditches using jets has been developed. The principle of this system is based on the separation of the 2 actions: aeration and circulation.

It was concluded that the flow of the liquid in the channel can be successfully modelled using various theoretical approaches. The mean circulation velocity VC, the power dissipated P, and the Peclet number Pe are the 3 important parameters governing the circulation.

The oxygen transfer capacity of the system has been studied and compares favourably with that of conventional systems. The advantage of such systems over conventional ones has been discussed.
Influence of Nitrilotriacetate on the Elimination of Metal Ions by Coprecipitation with Ferric Hydroxide
Authors: Frimmel F. H. , Geywitz J.
Published: May 2018

The elimination of dissolved copper, zinc, cadmium and lead by coprecipitation with iron(III) hydroxide was investigated. The reaction conditions of the batch experiments were adopted from water treatment. Conditional distribution coefficients show the order Cd < Zn < Cu < Pb for increasing interaction of the metals with the ferric hydroxide. The presence of nitrilotriacetate (NTA) decreases the efficiency of the metal elimination. NTA is also able to remobilize metals from the metal enriched precipitation. There is a significant effect, even at low concentrations of a few µmol/l. Remobilization of Cu, Zn and Cd increases, remobilization of Pb decreases with reaction time. The “ageing” of the precipitation plays an important role for the yield of the reactions. From a broad application of NTA in detergents an increase of the concentration of dissolved metal species has to be expected.
Treatability Studies and Toxicity Reduction in Pulp and Paper Mill Effluents
Authors: Galvão F° J. B. , Grieco V. M. , Araújo R. P. A. , Ortolano M. R. , Bertoletti E. , Ramos M L. L. C.
Published: May 2018

A study of the liquid effluents of various production process stages and of the final effluent of the RIPASA S/A Celulose e Papel plant, by means of conventional parameters and toxicity, was undertaken. Using these parameters, the performances of the current treatment system (an aerated pond) and of pilot-scale experimental systems (using aerobic biological processes with one or two stages) were compared. The two-stage system yields better results in the improvement of final effluent quality. Biological degradation rates were also determined. It is thought that these discharges will not have an impact on the receiving water, as far as toxicity is concerned.
New Ideas on Pollution Control in the Pulp and Paper Industry – Are There Any?
Authors: Airanne O. , Ruonala S.
Published: May 2018

The development of the pulp and paper industry is reviewed. It is pointed out that production processes must now consider environmental concerns in addition to the suitability of the final product. The difficulties of defining the total harmful effects of a process are outlined. It is concluded that there has been good progress from the environmental point of view, and that in the future, choices must be made to allocate scarce resources so that output in terms of environmental quality is maximized.
Recent Developments in Process and Reactor Design for Anaerobic Wastewater Treatment
Authors: Aivasidis A. , Wandrey C.
Published: May 2018

There are a large number of advantages in using microbial anaerobic degradation processes in wastewater pretreatment. However, a disadvantage of this method is the relatively long doubling times of anaerobic microorganisms. Because of the autocatalytic nature of the microbial processes and the low carbon incorporation rate which results in low biomass concentrations in continuously operated systems, decoupling of the residence times for substrate and biomass in necessary. In this way, high volume time yields of biogas can be achieved under anaerobic conditions. From the well known methods for achieving biomass retention, immobilization on inert support media is thought to be an effective alternative. Experiments on anaerobic treatment of sulfite evaporator condensate using immobilized microorganisms were carried out in a 12 1 fixed bed loop reactor. Porous sintered glass with a porosity of about 50% and a mean pore diameter of 60-100 µm served as the media. The reactor was operated for several months under steady state conditions at different residence times. At a residence time of 11 h, 84% of the COD was removed at loading rates up to 100 kg COD.m3.day. By optimization of porosity and pore size distribution a further improvement in the volume time yield of biogas was possible. Using reticulated sintered glass with a porosity of 60% and a pore size distribution of 60-300 µm, COD removal rates up to 160 kg/m3.d could be obtained. Experiments are currently being carried out with a pilot plant (reactor volume of 1.0 m3). This is necessary to obtain the characteristics necessary for scale up and calculating the economic viability of the process.
High Molar Mass Lignin in Bleached Kraft Pulp Mill Effluents
Authors: Sågfors P.-E. , Starck B.
Published: May 2018

The proportion of high molar mass (M > 1000D*) substances (HMM) in acid and alkaline bleaching effluents from kraft pulping has been studied by means of analytical gel permeation chromatography, GPC. The amount of HMM substances in alkaline effluents was found to be 65 - 75 % and in acid stage effluents 20 % of the UV-absorbing (A280 nm) components. Lignin is the precursor of the HMM substances in the alkaline stage, and lignin and carbohydrates are the precursors of the acid stage HMM substances.

For the purpose of characterization the HMM compounds were separated from low molar mass substances by preparative GPC. The IR spectra of both alkaline and acid stage substances in their neutral form had strong bands characteristic of carboxylic salts. There were no aromatic bands in the spectra of softwood HMM substances. In the spectra of hardwood substances a narrow aromatic band of low intensity was found in two alkaline stage HMM samples originating from mills using a high proportion of ClO2 to chlorine. Elemental analysis of the alkaline stage HMM substances showed that the chlorine content was as high as 9.8 % when the ClO2 charge had been small and less than 4 % with a large ClO2 charge. The low methoxyl group content and high oxygen content showed that the substances were largely oxidized. The LC50 test with water flea indicated no acute toxicity.
Sublethal Effects of Chlorinated Phenols and Resin Acids on Rainbow Trout (Salmo gairdneri)
Authors: Tana J. J.
Published: May 2018

The aim of this work was to study the effects of toxic compounds in pulp and paper mill effluents on fish and fish physiology. This was done by studying the accumulation of 2,4-dichlorophenol, 2,4,6-trichlorophenol and dehydroabietic acid in fish and the physiological responses of fish to this accumulation. Tests were performed at two concentrations, 5 µg/l and 50 µg/l, and during the exposure period mainly hematological parameters were measured in the fish. The toxicants tested affected most of the parameters analysed (blood hematocrit, leucocrit, hemoglobin, mean cellular hemoglobin count; plasma glucose, lactate; liver glycogen). Significant changes were also found in enzyme concentrations of UDP-glucuronyl transferase activity in the liver. Chlorinated phenols seem to increase the activity of this enzyme while the resin acids seem to decrease the activity. The accumulation of the toxicants tested is most significant at the beginning of the exposure period and the toxicants are concentrated in the liver. After 20 days of exposure the concentrations in the liver decrease and this shows the ability of fish to eliminate the substances tested or to change them to an excretable form. The accumulation of the toxicants seems to correlate with the physiological responses of the fish.
Effects of a Bleached Pulp Mill Effluent on Growth and Gonad Function in Baltic Coastal Fish
Authors: Sandström O. , Neuman E. , Karås P.
Published: May 2018

Growth and reproductive capacity in perch (Percafluviatilia L.) and roach (Rutilusrutilus (L.)) were studied during 1983, 1984 and 1985 in a coastal area of the Bothnian Sea affected by bleached pulp mill effluents. Comparative investigations were made at a mill producing unbleached pulp. In perch exposed to bleachery effluents effects were observed on length increase rates, somatic condition factors and on gonad development. The fraction of fishes displaying inhibited gonadal recrudescence was high close to the mill, and the size of developing gonads was comparatively small. Growth was faster in exposed fishes, in young-of-the-year as well as in older fish. Effects on length growth could be distinguished as far back as in 1975. Energy storage, expressed as the condition factor, was highest in exposed fishes. The effect pattern was more diffuse in roach, but examples of reduced gonad growth were noted. In conclusion, these studies provided evidence for changes in the energy allocation system in fish exposed to a bleached pulp mill effluent.
Environmental Fate of Chloroguaiacols and Chlorocatechols
Authors: Allard A.-S. , Remberger M. , Viktor T. , Neilson A. H.
Published: May 2018

An account is given of microbial transformations of chloroguaiacols and chlorocatechols. Experiments were carried out with pure cultures of aerobic bacteria and endogenous anaerobic bacteria in contaminated samples of sediment. Particular attention was directed to the role of environmental parameters in determining the fate of compounds discharged into the aquatic environment and to the potentially toxic effects of metabolites. An attempt has been made to assess the environmental significance of the results of laboratory experiments, and the data incorporated into a hypothetical ‘guaiacol cycle'.
Investigation into Mechanisms of Microbial Effects on Iron and Manganese Transformations in Artificially Recharged Groundwater
Authors: Bao-rui Yan
Published: May 2018

After artificial recharging of groundwater some problems occurred, such as changes in groundwater quality, the silting up of recharge (injection) wells, etc. Therefore, the mechanisms of microbial effects on groundwater quality after artificial recharging were studied in Shanghai and the district of Changzhou. These problems were approached on the basis of the amounts of biochemical reaction products generated by the metabolism of iron bacteria, sulphate-reducing bacteria, Thiobacillusthioparus, and Thiobacillusdenitrificans. The experiments showed that in the transformations occurring and the siltation of recharge wells, microorganisms play an important role, due to the various chemical and biochemical activities. A water-rock-microorganisms system is proposed, and some methods for the prevention and treatment of these effects are given.
Biological Degradation of Volatile Chlorinated Hydrocarbons in Groundwater
Authors: Milde G. , Nerger M. , Mergler R.
Published: May 2018

Chlorinated organic solvents - such as tetrachloroethene, trichloroethene and 1.1.1-trichloroethane - are the most frequently used compounds e.g. for degreasing in all branches of industries.

Due to their widespread use, their large consumption quantities (Fed.Rep.of Germ. 180 × 103 t/a) and their physical properties, these organic solvents are the most important point-source of groundwater contamination.

A serious case of soil, soil air and groundwater contamination by these organic solvents (maximum concentrations detected were 500 mg/kg, 7g/m3, 50 mg/l respectively) is reported, caused by the metal industry, rendering plant and paper production.

A special effect is the comparatively rapid degradation sequence of tetrachloroethene to trichloroethene to cis-1,2-dichloroethene and to vinyl chloride. Concentrations of cis-1,2-dichloroethene observed in groundwater were up to 1600 µg/l and of vinyl chloride up to 120 µg/l, respectively, although none of these substances were primary pollutants in the investigated area.

Results of laboratory tests give rise to the suggestion that degradation of chlorinated hydrocarbons in contaminated areas is mainly by microbiological means.

This effect is of special hygienic relevance, due to the fact that one of the metabolites, vinyl chloride, is known to be a human carcinogen and the polluted area (approx. 4 km2) is located in a catchment area of a waterworks.
On the Utilization of Biological Methods in Groundwater Treatment
Authors: Mälkki E.
Published: May 2018

Biological water treatment has been used for more than a century. The processes involved, however, have not been optimally utilized, since knowledge about their character and significance has been insufficient. As conventional water purification techniques developed, the use of biological processes remained in the background until a few decades ago. However, at the moment several biological treatment methods are in use to remove iron and manganese from groundwater, and the future looks promising. The same methods can be used to improve numerous other water quality parameters, e.g. to oxidize reduced nitrogen compounds into nitrates. Biological removal of nitrate, too, will be a future water treatment method.
Biological Treatment of Groundwater in Basins with Floating Filters–I. Test Arrangements and General Results
Authors: Mälkki E.
Published: May 2018

The research project deals with biological treatment of groundwater, in particular, the removal of iron and manganese in basins equipped with, primarily, floating coarse-grained filters that constitute the pre-treatment unit. This unit, which complements the sand filter, is actually the principal treatment unit. In the “pre-treatment unit” water flows recurrently through the floating filter and through the boundary surface between air and water. This promotes chemical oxidation, creates favourable conditions for biological activity and accelerates the sedimentation of the precipitate on the bottom of the basins. In the pre-treatment unit the precipitation process for iron in the different test plants (7 plants) started effectively within 1 to 5 months, the reduction being 82-95%. For manganese the reduction was from 0 to 83 %. After the sand filtration unit iron was almost totally removed and at three test plants also the manganese reduction was at least 80%. At some of the plants the said time was not sufficient to get the precipitation process for manganese going. The groundwater treatment result is influenced, in addition to technical arrangements, in a decisive way by the physico-chemical and microbiological quality of the raw water.
Homogeneous Catalytic Oxidation of Aqueous Sulfur(IV) by Transition Metal Ions, Part III: Effect of Iron(III), Copper(II) and Manganese(II) and Synergistic Catalysis
Authors: Reda M.
Published: May 2018

The general effects of Fe(III), Cu(II) and Mn(II) on the homogeneous catalytic auto-oxidation of aqueous sulfur(IV) were investigated. The results indicated that Fe(III) and Mn(II) are effective catalysts, and Cu(II) has a slight catalytic effect compared with distilled water. The apparent synergisms existing between Mn(II) and Cu(II), Mn(II) and Fe(III), and Fe(III) and Cu(II) were investigated.
Solid Waste Management: Recovery of Energy and Useful Materials
Authors: Aziz M. A.
Published: May 2018

Solid waste is a valuable resource. If managed properly, it can be an endless source of energy and useful materials. In this paper, the author highlights the salient features of solid waste management systems for producing energy and useful building materials with special reference to Singapore and some other Southeast Asian countries.
Landfarming for Treatment and Disposal of Oily Wastes Originating in the South Petrochemical Complex
Authors: Rangel Carla M. P. , Frantz José Henrique , Bastiani Moacir
Published: May 2018

Landfarming, a waste treatment system using biological degradation, has been very successfully used for the decomposition of oily sludges. This paper presents data on a project recently developed by COPESUL (Companhia Petroquimica do Sul) on implementation of this system as a solution for the disposal of oily sludges. The characteristics of this project are very different to those of other projects already operating in Brazil. It was due to the experience of these other projects that some modifications were introduced in the COPESUL project. The site chosen for disposal was divided into six parallel cells provided with internal roads to allow the easy access of equipment. The cells were made impermeable by means of a structure composed, from bottom to top, of: a layer of unsaturated natural clay with a minimum thickness of 3.60 m (with the top 15 cm compacted); a draining ballast, for safety purposes, which collects the liquid if this percolates through the top impermeable layer; an impermeable layer with a minimum thickness of 50 cm, obtained by compaction of the local clay; and a reactive layer, properly prepared to receive the sludge. The system is also provided with tanks to receive the waste to be treated and for storage of rainwater leachate which is collected and transported to SITEL (Integrated System for Treatment of Liquid Effluents) for treatment. Furthermore, a storage area for drums is provided for wastes delivered in this form. In addition to data on the project, the paper also gives details of the characteristics of the wastes, the monitoring plan, investment costs, and operating data.
Optimisation and Uprating of Activated Sludge Plants by Efficient Process Design
Authors: Chambers B. , Jones G. L.
Published: May 2018

Requirements to improve effluent quality and reduce operating costs at existing activated sludge plants in the UK have led to the development of an accurate mathematical model of the process which can be used for full-scale design. The WRc Activated Sludge Model has been developed over a number of years and is based on the concept of describing the kinetics of BOD removal by including a Monod term for growth and a Michaelis-Menten term for enzymatic activity. Since the first formulation of the model, further equations have been added which describe the use of oxygen and nitrate as electron acceptors for the conversion of BOD.

The model equations can be used to predict the performance of most configurations of the activated sludge process by using the ‘tanks in series' concept to describe aeration tank mixing characteristics. Solutions to the equations are easily obtained by standard numerical integration techniques using a computer. The software has been written in such a way that the model can be used interactively by a plant designer.

Results obtained using the mathematical model have been used to redesign several full-scale activated sludge plants in the UK. In some cases, it has been possible to reduce the energy costs for aeration by 40% whilst maintaining effluent quality by accurately matching the supply of oxygen to the spatially-varying oxygen demand in plug-flow aeration tanks. Bulking sludge problems have also been solved by the conversion of completely-mixed aeration tanks to plug-flow aeration tanks with complementary redesign of the aeration system.
Investigations of Secondary Settling at a Large Treatment Plant
Authors: Lumley D. J. , Balmér P. , Adamsson J.
Published: May 2018

The sedimentation phase of the activated sludge process has a large influence on the effluent quality of secondary wastewater treatment plants. Increasingly stringent effluent guidelines emphasize the need to improve the performance of secondary settlers. Full scale studies of rectangular settlers, at a secondary treatment plant with an average flow of 4 m3/s, were made. The non-settleable fraction of the effluent suspended solids defines an upper limit to settler efficiency. Polymer can be used to enhance settling when dealing with peak flow situations. The mass of solids in the settler, needed to calculate a mass balance of the activated sludge process, can be estimated by a simple model based on the sludge blanket depth and the average concentration of the sludge blanket at a central location in a settler. On-line instruments are useful for monitoring rapid and periodic changes in the state of the activated sludge process.
The Infuence of the Depth of the Secondary Sedimentation Tanks on the Sedimentation Efficiency at Bromma Sewage Treatment Plant
Authors: Tendaj-Xavier M. , Hultgren J.
Published: May 2018

Bromma sewage treatment plant is the second largest plant in Stockholm with a design flow of 160,000 m3/d.

The wastewater is treated mechanically, chemically by pre-precipitation with ferrous sulphate, and biologically by the activated sludge process. The requirements for the plant are 8 mg BOD7/l, 0.4 mg P/l and 2 mg NH4+-N/l. The requirement for ammonia refers to the period July-October.

In order to meet those rather stringent requirements, the biological step was expanded 3 years ago with 6 new sedimentation tanks. The 6 new tanks have the same area as the 6 old ones but they have only a depth of 3.7 m compared with the depth of the old tanks, 5.7 m.

Experience from the first years of operation of the new tanks is that these tanks are more sensitive and less efficient than the older ones. It seems that the effluent suspended solids concentration from the old tanks is less influenced by rapid flow variations than the concentration in the effluent from the new secondary sedimentation tanks.

During the nitrification period denitrification takes place to some degree in the secondary sedimentation tanks. This may cause loss of solids and it has been observed that the deeper old tanks usually produce an effluent of better quality and seem to be less influenced by denitrification than the new ones.
Effect of Activated Sludge Processes on Secondary Settling Tank Efficiencies
Authors: Koníček Z. , Burdych J.
Published: May 2018

Some calculations and experimental work on the turbulence in aeration tanks using different aeration systems and its effect on floc cohesion are presented. Vigorous aeration causes floc dispersion and it can be quantified in standard test conditions using velocity gradient calculations and comparing these with the numbers of particles in the supernatant liquor after 30 minutes settlement of the sludge. Tests on final settlement tanks indicated that the density current is of prime importance and that the harmful effects of this can be overcome by installing deep inlets and arranging to have the outlet weir inset and as near to the inlet as possible. Mixing calculations also indicated that circular tanks are more efficient than rectangular and that if the latter were used transverse flow is better than longitudinal flow. A test on a full scale plant indicated that flocculation occurred in the density current zone of the final tank so that the number of particles in the supernatant decreased to an extent similar to that produced by mild agitation.
The Use of Submerged Biological Filters for Nitrification
Authors: Schlegel S.
Published: May 2018

Trials using submerged biological filters, made of moulded polyethylene and aerated by compressed air, are described. The tests included operation in an activated sludge type plant with sludge recycle as a single stage filter, and as the second, nitrification, stage of a 2-stage system. Observations on the type of biological growth formed and on the need to have good hydraulic conditions to prevent clogging are made. Some design criteria are given.
Joint Sewage Treatment Plant I, Moenchengladbach-Neuwerk–A Review of the Past 50 Years and its Future Upgrading
Authors: Kugel G. , Zingler E.
Published: May 2018

The paper describes the changes which have been made to the plant since it was built in the 1930s. It was initially designed to treat 50,000 m3/d by a 2-stage activated sludge process with integrated charcoal precipitation and was enlarged 25 years ago to treat 130,000 m3/d dry weather flow. It now treats a population equivalent of 650,000, half of which is industrial effluent mainly from textile and food processing factories.

Sludge treatment has always included digestion and this is to be upgraded to 2-stage thermophilic and mesophilic digestion with submerged combustion sludge heating. The sludge produced has always been disposed of to land, with or without drying, using digester gas, and some has been centrifuged. The gas has also been used for car fuelling but it is now purified and blended into the gas supply of a public utility.

The sewage treatment is also to be upgraded mainly to deal with increased storm water flows.
Transfer of Heavy Metals from Suspended Sediments to the Alga Stichococcus Bacillaris in an Estuarine Water Medium
Authors: Ahlf W.
Published: May 2018

A bioassay has been carried out to determine the uptake of selected heavy metals from resuspended freshwater sediment by Stichococcusbacillaris. An apparatus was used in which a 0.45 µm pore diameter membrane separated the algae and particulates. When used with anestuarine water medium, this method demonstrated the release of heavy metals from particulates and subsequent bio-accumulation for some metal species. The amounts of metals accumulated in the algae indicated that the influence of salinity was important for distributions of metals in water, particulates, and algae.
Identification of Oil Spilled at Sea by High Performance Gel Permeation Chromatography Pattern Recognition
Authors: Higashi K. , Hagiwara K.
Published: May 2018

Oil pollution in the marine environment has now become a world-wide concern. Recently, in Japan, over 1,000 cases of oil pollution have been occurring every year. It is important to develop an effective identification method for spilled oils for conservation of marine environments. A new method was developed using high performance gel permeation chromatography (GPC). Chromatograms of the molecular weight distribution of oils were obtained using an ultra-violet (UV) detector. Pattern similarities between pairs of chromatograms were calculated by section areas of the chromatograms using a computer. Sixty two kinds of crude oil imported by Japan were classified by this method, and a close relationship was found between the countries of origin of the crude oils and their chromatographic patterns. Forty nine tar balls sampled from Japanese coasts were compared with the crude oils, and the origins of the tar balls were deduced. The proposed method was effective for the identification of spilled oils, and had high sensitivity and reproducibility.