bluuebunny/crossref_metadata_2025 huggingface dataset:
Waste Stabilization Pond Prediction Model
Authors: Preul H. C. , Wagner R. A.
Published: May 2018

This paper presents a prediction model for calculating the expected effluent performance of a facultative waste stabilization pond. The model is intended to improve on current design approaches through more appropriate recognition of physical and climatic factors which affect the prediction of pond performance. The importance of hydraulic routing throuah a pond is stressed along with wind mixing, thermal stratification, pond geometry, and other basic design parameters. The final form of the model is a working equation based on analyses of the various pond processes; because of the complexity of the final analytical model, it must be applied using computerized methods.
Aeration and Water Hyacinths in Waste Stabilization Ponds
Authors: Thomas P. R. , Phelps H. O.
Published: May 2018

The investigation was based on two facultative stabilization ponds initially designed to operate in parallel, and now receive wastewater in excess of their capacities from a fast expanding housing estate in the Caribbean Island of Trinidad. Because of the deterioration of the effluent quality relative to acceptable standards, an attempt was made to upgrade the ponds using water hyacinths at the early stages. However, from the results, it was clear that the introduction of water hyacinths in the test pond did not lead to any substantial improvement in the effluent because of the high loading on the pond. Therefore the ponds were modified to operate in series with surface aerators installed in the first pond. Initially, the effluent quality was monitored in terms of total suspended solids, volatile suspended solids, biochemical oxygen demand, faecal coliform bacteria, pH and dissolved oxygen with aeration in the first pond and no aquatic plants in the second pond. Although there was a significant improvement in the effluent quality, the values remained above the standards. As a result, water hyacinths were introduced in the second pond and the effluent quality monitored together with aeration in the first pond. The effluent quality improved with total suspended solids and biochemical oxygen demand values both as low as 10 mg/l in certain months, but additional treatment was needed to reduce faecal conforms.
Wastewater Treatment in Stabilization Ponds with Higher Aquatic Plants
Authors: Tsiprijan V. I. , Kravets V. V.
Published: May 2018

Higher aquatic plants (HAP) provide more effective tertiary wastewater treatment in biological ponds. They also accelerate the clean-up process with simultaneous increase of hydraulic loading. There was observed not only high removal efficiency for domestic organics, but also for various universal pollutants such as oil, synthetic surface active substances and phenols. Our findings have demonstrated that HAP stabilization ponds may be used successfully for industrial waste water treatment. We have also shown it expedient to apply the method in biological, biochemical and vitamin production plants and sugar refineries. HAP of reed, cane and rush proved to be the most effective plants to use.
Stabilization Ponds in South-West France: Effluent Quality
Authors: Boutin P. , Satese des Deux-Sèvres
Published: May 2018

Long-term surveys were performed on three stabilization ponds. Experimental results concerning effluent quality are briefly presented and discussed.
Algal-Bacterial Ponding Systems for Municipal Wastewater Treatment in Arid Regions
Authors: Esen I. I. , Puskas K. , Banat I. , Al-Daher R.
Published: May 2018

A pilot plant was constructed to investigate the use of algal-bacterial systems to treat municipal wastewaters in arid regions. The pilot plant consists of sand and oil traps, weir tanks, two facultative ponds (250 m3 holding capacity each), two high-rate ponds (25 m3 holding capacity each), four sedimentation tanks, a sludge digestor, and such auxiliary facilities as a pumping station for wastewater supply, drainage systems, and a site laboratory. The main objectives of the study are to determine the design parameters needed for large-scale algal-bacterial ponds in hot climates and to determine the degree of treatment and disinfection attained in the system by operating the pilot plant. After the algae is separated from the treated water, the final effluent will be used for irrigation, and algae will be used as a soil conditioner.

Investigations during start-up, test runs and experiments completed so far focused on the growth of algae and removal of biochemical oxygen demand, chemical oxygen demand, and suspended solids. During the 20-month experimental program, various operating patterns, including series operation of facultative and high-rate ponds, will be investigated. Results obtained so far indicate significant reductions in pollution concentrations.
Sewage Stabilisation Ponds in Arabia and Kenya
Authors: Smith L. J.
Published: May 2018

Experience of pond design and operation in Arabia and Kenya is described.

In Saudi Arabia major stabilisation pond installations were built for the Three Cities Project at Hofuf, Buraidah and Qatif. Summaries of results, comment on performance achieved and implications for future stabilisation pond design are noted.

Recently commissioned ponds in Aden for both domestic and industrial sewages are featured and points of interest indicated.

The basis of the most recent designs now ready for tender for applications in Aden and Seiyun, P.D.R. Yemen are provided.

Conclusions are drawn regarding the future potential of pond treatment for disposal of waste water for re-use in irrigation.
Steel Industry Wastes Treatment in Buffer Ponds
Authors: Bagnyuk V. M.
Published: May 2018

The bioprocesses of steel industry wastes self-purification in buffer ponds have been studied. The representatives of 6-7 divisions of microalgae and many functional groups of bacteria have been found in the ponds. The important role of a new functional group, the “lytic” microorganisms, in the regulation of microecosystems and in bacterial self-purification has been established.

It was found that the activity of self-purification bioprocesses in the buffer ponds studied depends on a variety of ecological factors. The main limiting factor has been shown to be the high turbidity of water, and its deficit of dissolved phosphates and oxygen.

To accelerate the self-purification of steel industry wastes in buffer ponds the concentration of organic and mineral forms of the main biogenic elements (C,N,P) should be regulated. Water clarification and aeration were recommended and effectively used.
Effects of Lagoon Treatment on Helminth Eggs
Authors: Schwartzbrod J. , Bouhoum K. , Baleux B.
Published: May 2018

In this study, we have investigated the effect of lagoon treatment on the elimination of helminth eggs. The Marrakech treatment lagoon receiving only part of the city sewage, consists of two connected ponds (total retention time from 8 days to 30 days). Water samples (surface and deep) and sediment samples were collected. In the surface water samples collected at the lagoon entrance there was an average of 11.7 eggs/l, while no helminth eggs could be recovered at the exit from the lagoon. In the two ponds very few eggs were found, both in surface and deep water samples (͌ 3/1). Helminth eggs were mostly found only in the sediment samples: 275 eggs/100 g sediment from the first basin and 158 eggs/100 g sediment from the second, on average. In conclusion, this study demonstrates that lagoon treatment is efficacious in removing helminth eggs. Nonetheless sediments from such treatment present a problem as they remain heavily contaminated with helminth eggs.
Development and Application of an Energy Utilization System for Organic Wastewater
Authors: Shinian Chen , Guangyu Yan
Published: May 2018

The main characteristic of an energy utilization system for organic wastewater is the combination of treatment structures with oxidation ponds, thus compensating for their deficiencies. Depending on the different environmental and economic conditions, various types of treatment can be used and can work well. The main features of the system are as follows: 1. alteration of the microbial phase by using high-energy aquatic plants in place of algal-bacterial systems; 2. Reduction of the problem of pond size by: including the ponds as part of urban afforestation areas; increasing the capacity of treatment sites by designing the ponds as a tower or steps; if land is limited, using pretreat-ment to reduce the size of ponds; 3. the utilization of solar energy to carry out the energy conversion of chemical exergy, avoiding the conversion of exergy into anergy. The energy consumption can be minimized and the problem of aquatic plants in the ponds during winter can be partially solved.
Microalgal Harvesting by in situ Autoflotation
Authors: Sandbank E. , van Vuuren L. J.
Published: May 2018

Dissolved Air Flotation (DAF) principles were applied to harvest microalgae from high rate algal pond (HRAP) effluents in a highly simplified system which consisted of an open channel and a dosing pump only. Polyelectrolyte solution is dosed into the channel through a diffuser in the vicinity of a paddle wheel, where rapid mixing occurs. Slow mixing takes place in the channel. While flocs grow, oxygen bubbles resulting from algae photosynthetic activity are entrapped. Floating flocs are removed manually at the end of the channel. Removal efficiencies of 90% were obtained at a 10 mg polyelectrolyte dose. The float had 4 to 6% solids which dewatered easily to 10% solids.
Waste Stabilization Ponds as Teaching and Research Tools
Authors: Hall A. , Duarte A. C. , Oliveira J. P.
Published: May 2018

In any campus where there is an excess of land or where a decorative pond is available, it is often possible to establish a system of waste stabilization ponds (WSP) to be used as an open air research laboratory, as source of water for watering the campus grounds and as a demonstration unit for the community at large. One such system, comprising one photosynthetic and one macrophyte pond in parallel, followed by one fish and one irrigation pond in series, was built at the Faro Polythecnic in Portugal. The ponds are proceeded by an underground unit formed by three septic tanks in series followed by two upflow anaerobic filters in parallel. This system is expected to receive 120m3/day of a mixed effluent coming from the sanitary facilities, the refectory and the fish processing laboratory, with concentrations of about 600mg/l in both BOD and SS.
The Development of Ecological Wastewater Treatment and Utilization Systems (EWTUS) in China
Authors: Wang Baozhen
Published: May 2018

Experience and practice of the treatment and utilization of sewage and organic wastewaters using stabilization ponds with artificial or semi-artificial ecosystems in China are described. The eco-ponds being used in China are different from those with symbiotic algae/bacteria systems in that the former consist of not only bacteria and fungi as decomposers and algae as producers, but also fish, shrimps, shellfish, ducks, geese, etc. These are consumers at different trophic levels in food chains or food webs in the pond communities where fish farming and/or duck and geese raising takes place. The eco-ponds are characterized by low capital and operation costs, energy savings, high removal efficiencies for a wide variety of pollutants, and considerable Drofits that can be gained from comprehensive utilization of wastewaters as recoverable resources.

Some typical eco-ponds for treatment and utilization of municipal and industrial wastewaters, such as fish farming ponds in Changsha, (Hunan), and in Ehcheng, (Hubei), hydrophyte ponds in Shaoxing, (Jejiang) and in Shijiazhuang, (Hebei), and treatment/storage lagoons with ecosystems are described in detail.

The concept of ecological systems for treatment and utilization of wastewaters, and the various ecological wastewater treatment and utilization systems (EWTUS) available for different regions, are also discussed in this paper.
Treatment of Wastewater in the Rhizosphere of Wetland Plants – The Root-Zone Method
Authors: Brix Hans
Published: May 2018

The present paper describes the theoretical basis of wastewater treatment in the rhizosphere of wetland plants, the so-called “root-zone method”, along with the first working experiences from eight treatment plants in Denmark.

Mechanically treated wastewater is led horizontally through the rhizosphere of wetland plants. During the passage of the wastewater through the rhizosphere, the wastewater is cleaned by microbiological degradation and by physical/chemical processes. The wetland plants supply oxygen to the heterotrophic microorganisms in the rhizosphere and stabilize the hydraulic conductivity of the soil. Nitrogen is removed by denitrification and phosphorus and heavy metals are bound in the soil.

The first working experiences from Denmark show, that as far as BOD is concerned root-zone treatment plants are very nearly up to conventional secondary treatment standards already from the first growing season (removal efficiency: 51-95%). For the nutrients nitrogen and phosphorus the results vary (total-N removal: 10-88%; total-P removal: 11-94%). The removal efficiencies depended mainly on the composition of the soils and the degree of surface runoff in each treatment plant.

It is concluded that root-zone treatment plants seem to be a viable alternative to conventional wastewater treatment technology, especially suitable for single households and small to medium sized communities. There is, however, still very little information on the removal processes for nitrogen (denitrification), on the effect of soil type and on the required surface area to load ratio,
Anaerobic Treatment of Coal Gasification Wastewater
Authors: Suidan Makram T. , Fox Peter , Pfeffer John T.
Published: May 2018

A sequence of unit processes consisting of a berl-saddle-packed anaerobic filter, an expanded-bed, granular activated carbon anaerobic reactor and an activated sludge nitrification system was employed for the treatment of synthetically prepared coal gasification wastewater. After acclimation, the coal gasification wastewater was fed to the treatment process train at three different chemical oxygen demand levels; these were 1,513. 3,027, and 7,567 mg/ℓ, respectively. No biological activity was observed in the first-stage filter, while excellent removal of organic matter was achieved in the second and third stages of the treatment systems. However, toxicity to the anaerobic culture in the second-stage reactor was observed during the second and third loading levels. This toxicity was overcome by employing a partial replacement schedule of the granular activated carbon medium in the reactor. This study represents an example of how biodegradation and physical adsorption may be successfully combined during the treatment of wastewaters containing toxic or inhibitory substances.
Anaerobic Fluidized Bed Treatment with a Steady-State Biofilm
Authors: Yoda M. , Shin S. W. , Watanabe A. , Watanabe M. , Kitagawa M. , Miyaji Y.
Published: May 2018

The goal of this study is to find the operational conditions for establishing a dynamic balance between the microbial growth and loss in the anaerobic fluidized bed process. Such operation is very attractive because there is no necessity of complicated bed and biofilm control or costly excess sludge treatment and disposal. Several factors which control the dynamic balance were identified and experimentally determined using laboratory scale anaerobic fluidized beds. Based upon the knowledge accumulated through the laboratory experiments, a pilot scale anaerobic fluidized bed (1.0 m ID × 6.85 m H) was installed at a soft-drink bottling plant and successfully operated for nine months. The stable microbial mass along with low effluent organic concentration demonstrated the feasibility of the anaerobic fluidized bed treatment with a steady-state biofilm.
Economic and Environmental Benefits from Froth Flotation Recovery of Titanium, Zirconium, Iron and Rare Earth Minerals from Oilsand Tailings
Authors: Ityokumbul M. T. , Bulani W. , Kosaric N.
Published: May 2018

The froth flotation recovery of titanium, zirconium, iron and rare earth minerals from oil-sand tailings and their further beneficiation are described in this paper. The recovery of rare earth mineral value from these tailings has not been reported previously due to their low concentrations. The economic value of all of these minerals recovered in this way has been estimated to be almost double the cost of full effective tailings management. Adoption of these processes can eliminate the current unsound practice of simply storing these tailings behind high dykes in large lagoons.
Biodegradation of Oil on Drilled Cuttings
Authors: Bilstad T. , Bosdal T. , Toerneng E.
Published: May 2018

Drilled cuttings from offshore petroleum exploration are discarded to sea. Oil based drilling fluids leave oil on cuttings that may become environmentally toxic.

Successful biological separation of oil and cuttings was accomplished by addition of nitrogen and phosphorus to seawater in completely mixed aerobic batch reactors at 10 and 20°C. Substantial biodegradation in flow-through aquaria, however, was not accomplished.

Both retort distillation and solvent extraction using dichloromethane in a Soxhlet apparatus separated reproduceable quantities of hydrocarbons from cuttings. The oil was characterized by glass capillary gas chromatography and medium pressure liquid chromatography.
Chlorinated Hydrocarbons in Biological Sewage Purification – Fate and Difficulties in Balancing
Authors: Schröder H. Fr.
Published: May 2018

The fate of some chosen chlorinated hydrocarbons in the biological sewage purification was determined. Fixed quantities (250 µg/l waste water) of the different volatile compounds such as chloroform, trichloroethylene, chlorobenzene, hexachloro-1, 3-butadiene, 1,2-dichlorobenzene, 1,2, 3-trichlorobenzene, hexach lorobenzene, 2,4-dichlorophenol and γ-hexachlorocyclohexane were dosed into the aeration tanks of the pilot plants. Chlorinated hydrocarbons in the inflow, waste air, effluent and excess sludge were extracted and tested for by GC/ECD. The results of these experiments were adapted with the results of recovery experiments. The balances of the low volatile and volatile compounds also had to be adapted by the means of correction factors because of condensation effects. For example more than 50 % of 250 µg/l water of chloroform or 1,2-dichlorobenzene escaped out of the open sampling bottles which were kept in a refrigerator during the sampling period of 24 hours. The balances of the non-volatile chlorinated hydrocarbons were reaching about 100%. The very hydrophilic and low volatile chloroform was found up to 16% in the waste air, 63% in the effluent and 21% adsorbed on sludge. The very lipophilic and non-volatile hexachlorobenzene was found up to 16% in the effluent and 74% adsorbed on sludge. No hexachlorobenzene was found in the waste air. Biochemical degradation was observed for some of these compounds.

The behavior of the chlorinated hydrocarbons in biological sewage purification depended on their volatility and lipophilic property, and also the intensity of aeration and sludge loading has been of great importance. Balancing of volatile chlorinated hydrocarbons should be done by spot sampling. Bottles for composite samples should be stored in the refrigerator during the sampling period and should be sealed.
Response of Phthalate Esters-Acclimated Activated Sludge to 2,4-Dinitrophenol
Authors: Yucel Tokuz R.
Published: May 2018

The process performance of an activated sludge system during acclimation to phthalate esters was examined. Concentration of the phthalate esters was increased gradually, and over about a two-week period, the acclimation to a mixture of 410 mg/L diethyl phthalate and 540 mg/L dimethyl phthalate was complete. It was observed that the effluent Chemical Oxygen Demand (COD) was not affected adversely in spite of increasing influent COD. Other indicators of process performance, for example, effluent suspended solids, were at acceptable levels at the completion of acclimation. The system responded well when 2,4-dinitrophenol, up to 4 mg/L, was included in the influent in addition to phthalate esters. Actually an improvement in system effluent COD was observed possibly due to increasing Mixed Liquor Suspended Solids (MLSS). At a 2,4-dinitrophenol concentration of 8 mg/L, system performance deteriorated considerably but the recovery was fast, and within a two-week period system performance returned to normal.
Survival of Indicator Organisms in a Detention Pond Receiving Combined Sewer Overflow
Authors: Lijklema Lambertus , Habekotté Barbara , Hooijmans Christine , Aalderink Roelof H. , Havelaar Arie H.
Published: May 2018

Removal of four groups of indicator bacteria and two groups of bacteriophages in a detention pond receiving Combined Sewer Overflows (CSO) were measured. Also the survival of the bacteria in the sediments was studied. The overall removal rate of the bacteria tended to be somewhat higher than the removal rate for phages. Most values were in the range of 0.7 - 1.0 per day (e-basis). Sedimentation was of limited importance except for a short period following the overflow event. Dilution contributed in a reduction of 0.3 - 0.4 per day and die-off rates were about 0.3 - 0.6 per day, for phages maybe as low as 0.2 per day. Survival of the bacteria in the sediment was much better than in the water, net loss rates were about 0.1 per day, resulting in a more or less continuous contamination of the sediment with pathogenic bacteria as represented by indicator organisms.
Maintenance Strategies for Sewerage Systems
Authors: Câmara A. S. , Pereira D. , Fonseca A. , Sequeira S.
Published: May 2018

The problem of decaying sewerage systems is a timely topic in many urban areas, due to its importance to societal needs and to the large amounts of capital expeditures needed to bring the concerned systems to an adequate level of serviceability. Thus, there is a need for better maintenance decision-making related to periodic inspection and cleaning, repair, rehabilitation or replacement of the equipment.

In this paper, an approach offering integrated solutions to upgrade such systems, taking into account existing and foreseen structural and hydraulic conditions, is presented. The methodology relies upon a heuristic algorithm scheduling maintenance events. An application to the Almada sewerage network illustrates the method. Future improvements including the use of statistical maintenance theoretic concepts and artificial intelligence approaches are also discussed.
Socio-Technological Aspects of Automation in Public Works Activities
Authors: Garber William F.
Published: May 2018

The history of human society is replete with examples of advances in technology overrunning the ability of societal organizations to efficiently handle the resulting massive societal dislocations. The social impacts of the “Industrial Revolution of the 18th and 19th Centuries” illustrate how profound such effects can be.

The automation-computer-robotics revolution now underway also has the potential for serious societal changes. In this regard public works activities are subject to increasing amounts of automation with impacts upon current and net total employment and training needs. To evaluate the present status of automation in the USA, questionnaires were sent to public works authorities in 110 cities or agencies. The current degree of automation, the impact upon employment and the skills now needed by public works employers were queried. It was found that in most cases automation was just starting; but that as complete automation as was possible was inevitable given the increasing complexity of the tasks, the demands of the public and the long term prospects for public works funding.

In many cases the candidates now in the work force were not properly trained for automation needs. Retraining and changes in the educational system appeared necessary if the employees now needed were to be continuously available. Public works management as well as several labor organizations appeared to be aware of this need and were organizing to handle the training problem and the changes in employment qualifications now necessary. It appeared to be a consensus that the larger societal effects of automation should be handled by society as a whole.
Field Verification of On-Line Instrumentation at a Municipal Wastewater Treatment Plant
Authors: Speirs Gordon W. , Hill Robert D.
Published: May 2018

As part of a full-scale project to demonstrate the advantages of using automated process control in wastewater treatment plants, on-line sensors used in various control loops were calibrated and/or verified during control system commissioning and startup. The on-line measurements included liquid flow rates, air flow rates, suspended solids concentrations, and dissolved oxygen concentrations. The methods used to confirm instrument performance are presented along with results that show that several instruments were found to operate outside the manufacturers' written specifications. In addition, on-line methods which can help determine when recalibrations are required, and thereby help to reduce maintenance costs and ensure reliability, are also presented.
Optimization of Regional Water Quality Monitoring Strategies
Authors: Pintér J. , Somlyódy L.
Published: May 2018

A conceptual framework is presented for optimizing the operation of regional monitoring networks which assist water quality management. The primary objective of the studied network is to determine the annual nutrient load carried into a lake by its tributaries. Following the description of the basic (single time–period, single water quality indicator) model, several extension possibilities and computational aspects are highlighted. The suggested methodology is illustrated by a numerical example, concerning the surveillance system on the tributaries of Lake Balaton (Hungary).
Impact Prediction Method for Accidental River Pollution
Authors: Dutang M. , Bujon G.
Published: May 2018

Predicting the impact of accidental pollution is more difficult than that of continuous pollution, and describing the variability of the phenomena involved is not an easy task. The authors describe a simulation method using a sophisticated mathematical model which, when applied to an accidental spillage of toxic material, accurately determines its impact on water intakes downstream from the spill. The model is based on dispersal equations and makes allowances for the phenomenon of biological decay and the velocity gradient of the water in the river. It is used during simulations conducted by injecting a dye into the river.
A Survey for Salinity Intrusion and Pollution Assessment in Maputo Estuary
Authors: Salomão J. M.
Published: May 2018

Following surveys recently carried out in Maputo estuary, a survey with the purpose of acquiring data required to characterize the estuary was carried out in December 1983. After reviewing the hydrology of the tributaries to the estuary, the parameters to be monitored - salinity, conductivity, temperature, and dissolved oxygen, are referred. Finally, taking also into account previous information available, an evaluation of the results, and an assessment of the estuary are done. The estuary can be classified as well mixed, since the vertical salinity gradients found are small. The Umbeluzi estuary, however, is partially mixed. Temperature decreases with the depth, and when moving downstream. Some pollution was found along the lower part of the estuary, probably due to the discharge of domestic and industrial wastewater, which brings the dissolved oxygen figures below the saturation level. As for the upper part of the estuary, the dissolved oxygen levels are not only dependent on the pollutant load, but also on the growing of algae, which by photosynthesis under daylight produce oxygen that dissolves into the water. Quite often, the dissolved oxygen figures are above the saturation level. The growth of algae could be due to the input of phosphorus and nitrogen brought in by the tributary streams. A pollutant load discharged upstream could be the reason for some pollution seen in the Umbeluzi estuary.
Low Cost Controlled Composting of Refuse and Sewage Sludge
Authors: Pereira-Neto J. T. , Stentiford E. I. , Mara D. D.
Published: May 2018

The forced aeration static pile composting system was used to compost mixtures of domestic refuse and sewage sludge. Several different control methods have been evaluated over the past four years from simple, low cost fixed rate aeration timers to microcomputer based systems. Their relative merits are considered. In a compost pile using temperature feedback control the number of Escherichia coli were reduced from 107 org./g to less than 102 org./g. within 16 days. Faecal streptococci were reduced from 107 to less than 102 org./g within 30 days. The process consistently produced a good quality sanitised material under a range of control regimes.
Regional Sludge Treatment and Disposal Optimizing Reliability and Cost
Authors: Hahn Hermann H.
Published: May 2018

Sewage sludge is the consequence of successful wastewater treatment. With the increasing number of wastewater treatment facilities and increasing intensity of treatment the amount of sludge produced will grow. The task of sludge treatment and disposal will therefore assume a significant place in environmental quality control. Sewage sludge is considered both a valuable resource possibly for agriculture, and a waste material which must be disposed of safely. Thus, regional solutions must be aimed for if available sites for agricultural application or a limited number of disposal sites are to be used wisely. Technically and economically feasible alternatives of treatment (and disposal) are numerous. The selection process to be discussed in this paper is a minimization of overall cost and/or an optimization of process reliability and cost. There exist proven mathematical tools for the solution of such optimization problems; in this instance dynamic programming routines have been utilized. The applicability of these methods, as well as their limits, are shown in a practical case study.
Conditioning of Biological Sludges with Cationic Poly-Electrolytes
Authors: Eriksson L.
Published: May 2018

Factors determining polyelectrolyte choice and dosage in conditioning of activated sludge were investigated. It was found that due to differences in particle size distribution electrophoretic mobility did not correlate with optimal dosages. Instead the polyelectrolyte consumption to a large degree could be explained by a linear model containing the variables: sludge volume index, rest turbidity, floc break up factor obtained by CST-stirring test and CST (Capillary Suction Time) of unconditioned sludge.

For the investigated sludges biopolymers and colloidal particles were the main consumers of polyelectrolyte which however also was needed to build the existing flocs to optimum properties. The model was statistically less significant in the cases of high stirring times and high sludge volume indexes.

Sludges with high amounts of dispersed particles were best conditioned by a high molecular weight and moderately charged polymer while for well flocculated sludges with high sludge volume index a high charge density polymer was most suitable.
Dynamic Changes in Populations of the Activated Sludge Community: Effects of Dissolved Oxygen Variations
Authors: Hermanowicz S. W.
Published: May 2018

A simple dynamic mathematical model was developed to describe a microbial system composed of two populations: filamentous and floc-forming bacteria. Growth rates of both microorganisms depend on the concentration of a single organic substrate and on the dissolved oxygen (DO) concentration. Biokinetic parameters were estimated from the experimental data reported in the literature. Using these parameters population changes were examined under variable DO concentrations. The comparison of the numerical simulations and experimental data indicated a possibility of controlling population composition within a desired range through periodic changes in DO concentration. The existence of a single common trajectory on phase plane guarantees the stability of the designed cycle.
Influence of Oxic and Anoxic Mixing Zones in Compartment Systems on Substrate Removal and Sludge Characteristics in Activated Sludge Plants
Authors: Hoffman H.
Published: May 2018

During a research program the influence of activated sludge compartment systems with and without anoxic mixing zone on the efficiency of the system and the settleability and dewatering characteristics of the activated sludge was tested. COD-load, number and volume of the compartments and the mixing zones were varied.

Experiments were carried out with two pilot plants, a compartment system and a totally mixed system.

The tests clearly indicate that a four-stage cascade system with a BOD-load of about 1.0 kg/(m3.d) could improve settleability and dewatering characteristics, but bulking sludge could not be avoided.

Using a nonaerated upstream zone with a volume load of 4.0 kg/(m3.d)the settling properties in the compartment system(total BOD-load 1.0 kg/(m3.d)) could be improved to such an extent that the formation of bulking sludge was prevented.

Better settleability leads to the higher solids concentration in the cascade system and to a lower sludge load. Therefore lower BOD-outflow-concentrations and higher efficiency of the activated sludge system were available.
Polymerization Effects of Ozone: Applications to the Removal of Phenolic Compounds from Industrial Wastewaters
Authors: Duguet J. P. , Dussert B. , Mallevialle J. , Fiessinger F.
Published: May 2018

Degradation of phenols by ozone has been extensively studied but the oxidative coupling pathway of ozone resulting in a phenol polymerization has not been largely investigated. Application of low ozone dose in solutions of 2.4 dichlorophenol and salicylic acid is characterized by the formation of high molecular compounds which are partially insoluble. Numerous polymers have been identified by gas chromatography coupled with mass spectrometry. Application of the polymerization effect of ozone to petrochemical and coking wastewaters containing phenols give similar results. In each case, phenolic compounds are efficiently removed, even if a large organic content is present. In the case of petrochemical wastewater, where phenols represent only 30% of TOC, the ozone effects are not sufficient to merit an ozonation step on the present treatment line. On the other hand, when phenols represent the greater part of the organics, as in coking wastewater, an important fraction of insoluble compounds, easily removed by filtration, are formed.
Desorption of Cationic Polyacrylamide from Bleached Kraft Pulp Fibers
Authors: Warren Clifton F. , Gehr R.
Published: May 2018

The adsorption and desorption behaviour of a cationic polyelectrolyte contacted with wood pulp fibers was determined by total nitrogen analysis using a pyrolysis/chemiluminescence detection system. Dialysed polymer generated an adsorption isotherm of higher affinity than did non-dialysed polymer. Capacity adsorption was maximized at pH 7, but decreased in the presence of alum depending on the dosage. Desorption of non-dialysed polymer was caused by changes in pH above or below 7.0 as well as by addition of alum. However for the alum doses typically encountered in paper manufacturing, significant desorption is unlikely. Nevertheless, the contaminants in non-dialysed polymers do hinder adsorption, and effluents from those processes using both alum and polymer may contain quantities of unadsorbed or desorbed polyelectrolytes which could be damaging to receiving water bodies.
Requirements for the Treatment of Effluents from Chemical Pulp Mills in the F.R.G.
Authors: Huber L. , Baumung H.
Published: May 2018

In 1986, the 11 chemical pulp mills in the F.R.G. produced 350,00 t of bleached sulfite pulp. With the enactment of the so-called minimum requirements in 1982, general standards for the treatment of effluents were promulgated for this branch of industry. They comprise various measures, such as high-grade recovery of spent liquor including its evaporation and incineration, partial or total reuse of condensates from evaporation or reduction of their load by stripping, and mechanical treatment of total waste water. In view of the persisting high pollution levels of German rivers caused by pulp mills, more stringent standards reflecting the present state of the art will be implemented in 1991. This paper deals with these standards, covering the applicable in-plant and external abatement measures, such as extended cooking, substitution of elemental chlorine and biological treatment for decisive improvement of the chemical pulp mill effluent situation.
The Efficiency of a Biological Activated Sludge Effluent Treatment Plant with Extended Aeration
Authors: Skogman Rurik , Lammi Reino
Published: May 2018

The requirements imposed on the Finnish forest products industry by the water authorities have focused on the reduction of BOD and suspended solids in the wastewaters.

The industry has tried to comply with these requirements, first through internal measures such as process changes and closed systems. When these have not been sufficient, external treatment has been resorted to.

The Wilh. Schauman Company in Jakobstad has chosen activated sludge with extended aeration from among the available methods for treating effluent. The plant has operated since the beginning of 1986 with extremely good results. In addition to the reduction of BOD and suspended solids, there has been a marked decrease of chlorinated phenols. Chlorinated substances with higher molecular weight are also removed during the process.
Sludge Handling and Disposal at Finnish Activated Sludge Plants
Authors: Saunamäki R.
Published: May 2018

Between 1984 and 1986 a total of 13 activated sludge treatment plants were built in Finland to handle waste waters from the pulp and paper mills. With just a few exceptions these plants have come up to expectations, achieving BOD7 reductions of 80-95 %. These plants produce around 94,000 tonnes (dry weight) of sludge a year, of which some 27,000 tonnes is biosludge. On a mill basis, biosludge accounts for 10-50 % of total sludge. Generally speaking, the higher the loading at the plant, the more biosludge is produced. The yields of biosludge were 0.3-1.2 kgTS/(kgBOD removed) for a sludge load of 0.1-1.2 kgBOD7/(kgMLVSS*d). The biosludge is separated by sedimentation in clarifiers and thickened in round sedimentation basins to a consistency of 3-5 %. At one mill anaerobic sludge from an oversized thickener is returned to the aeration basin. The aim of this is to minimize the need for nutrient addition. Belt filter presses are normally used for sludge dewatering, the solids contents achieved being about 25-37 %. The difficulty of handling biosludge and the low solids contents achieved were considered by many mills to be the main problems of sludge handling. At one mill a drum press is used to press a pretreated mixture of sludge and bark to around 42 % consistency for burning. Six mills burn all or part of their sludge in a bark-fired boiler. On a dry weight basis the sludge burned normally accounts for 5-10 % of total fuel consumption. Burning sludge has been associated with a reduction in steam generation and an increase in running problems. The other method of disposing of sludge is landfilling. Sludge is not used as a fertilizer or soil improvement agent in Finland.
Anaerobic Treatment of a Mixture of Condensate and Caustic Extraction Liquor from a Dissolving Pulp Mill
Authors: Särner Erik
Published: May 2018

A mixture of condensate and caustic extraction liquor from a dissolving pulp mill was treated anaerobically in a pilot plant. The results showed that caustic extraction liquor could be used for pH control, and thus no chemicals were needed for this purpose. No toxic effects could be seen if the flow of caustic extraction liquor was kept in the range of 25-30% of the total flow. The anaerobic COD reduction averaged about 50% and the corresponding BOD reduction varied in the range 70-80%.
Evaluation of the ‘Fugacity' (FEQUM) and the ‘Exams' Chemical Fate and Transport Models: A Case Study on the Pollution of the Norrsundet Bay (Sweden)
Authors: Kolset Knut , Heiberg Anders
Published: May 2018

Two different models have been used to investigate how chemicals present in wastewater from a kraft mill are transported and spread in an aquatic environment. The models, FEQUM (Fugacity EQUilibrium Model) and EXAMS, are presented, their characteristics explained and a comparison of the models is made. In FEQUM the concept of fugacity is considered as the driving force behind chemical transport. The EXAMS dispersion model uses water and sediment flow as the basis for calculating the dispersion of chemicals. FEQUM encompasses the whole environment, water, air, soil, sediments, suspended matter in water and biota, whereas EXAMS includes the aquatic domain only.

Both models have been applied to the Norrsundet area. Norrsundet is a heavily polluted bay on the east coast of Sweden. The pollution is mainly due to a kraft mill located in the area. The models were calibrated using data on chloroform in wastewater and seawater, and then tested on four other pollutants present in the wastewater. Both models give satisfactory results for the compounds investigated, tetrachlorocatechol constituting the only exception. Correlation coefficients between calculated and measured concentrations vary from 0.86 to 0.97. The poor results obtained for tetrachlorocatechol are probably due to the especially high affinity of this compound for suspended particles.
Physiological Disturbances in Fish Exposed to Bleached Kraft Mill Effluents
Authors: Larsson Åke , Andersson T. , Förlin L. , Härdig J.
Published: May 2018

Physiological methods, previously used as health indicators in laboratory investigations on fish exposed to environmental pollutants, have been applied to feral fish inhabiting coastal waters polluted by bleached kraft mill effluents (BKME). The results show that BKME affect important physiological functions and thereby the state of health of the fish in the receiving body of water. Typical symptoms were reduced gonad growth, enlarged liver, strong induction of enzymes in the hepatic mixed function oxidase system, elevated content of ascorbic acid in liver tissue, altered carbohydrate metabolism, disturbed ion balance and marked effects on the red and white blood cell pattern. Good agreement was found between the toxic effects detected in fish exposed to BKME in nature and those observed in laboratory investigations. The toxic effects were most pronounced in fish living up to 4.5 km from the discharge source, but some disturbances could be observed even in fish caught 8-10 km from the kraft pulp plant. This indicates that the area of influence where the BKME exert biological effects is much larger than was previously considered.
Effects of Pulp Mill Effluents on Skeletal Parameters in Fish – A Progress Report
Authors: Bengtsson Bengt-Erik
Published: May 2018

In the Gulf of Bothnia the fourhorn sculpin (Myoxocephalus quadricornis) demonstrated elevated levels of deformed spine and/or vertebrae in areas polluted by bleached kraft mill effluents (BKME). Laboratory tests confirmed a correlation between the observed defects and BKME, diluted about 200-1000 times. Analysis of mechanical parameters (strength, elasticity etc) and chemical composition (Ca, P, collagen, proline, hydroxyproline) of single vertebrae confirmed the effects of BKME on bone characteristics in feral and laboratory exposed fourhorn sculpin. Similar effects were recorded also for feral perch (Perca fluviatilis) caught in the vicinity of a pulp mill and bleak (Alburnus alburnus) exposed to various BKME in the laboratory.

After about 4 1/2 months of exposure to 0.1 and 0.5 mg tetrachloro-1,2-benzoquinone/L fourhorn sculpin demonstrated vertebral deformities and aberrant mechanical properties of vertebrae. The results are discussed in relation to results obtained from feral fish exposed to BKME and fish exposed to BKME in the laboratory.

The recorded effects are suggested to be the results of long-term metabolic dysfunction, leading also to other serious effects in the organism.
Application of Environmental Risk Analysis to Groundwater Protection
Authors: Ettala M. O.
Published: May 2018

Industrial hazards can be divided into risks relating to property, persons, know-how and operations. The operational risks include risks to the environment, against which the industry in generally not insured. Environmental risk management is necessitated by the growth of legislation for environmental protection, by the economic losses involved in environmental damage and by the unfavourable image created by such damage for the industry. In 1985-1987, environmental risk analysis was applied at four factories and four refuse disposal systems in the fields of chemistry, forest industry and foodstuffs. The analysis covers organization of the different process stages, air pollution, waste disposal and problems connected with the surface and ground-water. Consideration of the groundwater risks must take into account the hydrogeological conditions, sources of pollution, use and monitoring of groundwater, and estimation of magnitude of damage. A wide variety of factors affecting the quality of the groundwater supply must also be included in the analysis. As in normal risk analysis, the study consists of identification and quantification of the risks and comparison of alternative measures. However, environmental risks were not found to be identifiable solely by fault tree of action error analysis, by hazard and operability study (HAZOP) or by management oversight and risk tree (MORT) analysis. As in other fields, specialists are needed for a site study of groundwater issues in the factories. Check lists were prepared for use when the personnel at different organization levels are interviewed. Serious environmental risks were found to be caused by deficiencies in the functioning of the organization, in information and allocation of responsibility. Permits, agreements, etc. had frequently been disregarded and many technical deficiencies had endangered the groundwater quality or supply.
The Vyredox and Nitredox Methods of in situ Treatment of Groundwater
Authors: Braester Carol , Martinell Rudolf
Published: May 2018

Nearly one fifth of all water used in the world is obtained from groundwater. The protection of water has become a high priority goal. During the last decades pollution of water has become more and more severe. Today groundwater is more and more used in comparison with surface water. Recently we have seen accidents, which can pollute nearly all surface water very quickly. Generally the groundwater is easier to protect, as well as cheaper to purify, and above all it is of better quality than the surface water.

During the past two decades, alternatives to the traditional method of treating the water in filters have been developed, that is in situ water treatment i.e. the VYREDOX and NITREDOX methods.

The most common problem regarding groundwater is too high content of iron and manganese, which can be reduced with the VYREDOX method. In some areas today there are severe problems with pollution by hydrocarbons and nitrate as well, and with modification of the VYREDOX treatment method it is used for hydrocarbon and nitrate treatment as well. The method to reduce the nitrate and nitrite is known as the NITREDOX method.