bluuebunny/crossref_metadata_2025 huggingface dataset:
Use in Agriculture of Sludge from Chemical Treatment of Sewage
Authors: Castillo G. , Ortega A.
Published: May 2018

The reutilization in agriculture of the sludge produced in the chemical treatment of sewage is investigated. Aluminium sulfate (50 mg/l) and sodium hydroxide (50 and 200 mg/l) are added to domestic sewage allowing it to settle and eliminating floating materials. Three kinds of raw chemical sludge are digested and dried. Their sanitary quality is determined by two bacterial indicators (total and fecal coliforms) and one viral indicator (E. coli bacteriophage) and the fertilizing capability of digested and dry sludge by sowing leguminous crops (Phaseolus spp ) in soil with 11 tons/ha sludge application rate. Digested and dried sludge from conventional treatment in equal conditions to those of chemical sludge is used as reference. Sanitary quality results show that raw and digested chemical sludge are not recommended for use in agriculture due to their high microbiological contamination. Dry sludge could be considered for this purpose due to its low fecal organisms content. However the development of leguminous crops in soil with dry aluminium sludge application shows no seed germination. The results of leguminous growth in digested sludge of sodium hydroxide (200 mg/l) justify an additional treatment to adequate its sanitary quality for use in agriculture.
Habitat Elements in River Basin Management and Planning
Authors: Herricks Edwin E. , Braga Maria I.
Published: May 2018

Comprehensive river basin management mast move beyond narrowly focused programs dealing with water quantity or water quality. A more comprehensive approach to river basin management recognizes that both flow quantity and water quality can be summarized as habitat measures. A number of well developed physical habitat analysis and prediction procedures are presently available. Several computerized systems available from the U.S.Fish and Wildlife Service (Habitat Suitability Index - HSI and PHysical HABitat SIMulation - PHABSIM) provide macrohabitat definition. We have developed a water quality based habitat component which operates effectively for general analysis. With an emphasis on site specific management in the United States, the macrohabitat definition procedures may not meet all river basin management and planning requirements. This paper reviews the results of research which characterizes microhabitat in streams and rivers and provides a valuable extension to basin management procedures.
Analysis of the U.S. Geological Survey Streamgaging Network
Authors: Scott Arthur G.
Published: May 2018

This paper summarizes the results from the first 3 years of a 5-year cost-effectiveness study of the U.S. Geological Survey streamgaging network. The objective of the study is to define and document the most cost-effective means of furnishing streamflow information. In the first step of this study, data uses were identified for 3,493 continuous-record stations currently being operated in 32 States. In the second step, evaluation of alternative methods of providing streamflow information, flow-routing models, and regression models were developed for estimating daily flows at 251 stations of the 3,493 stations analyzed. In the third step of the analysis, relationships were developed between the accuracy of the streamflow records and the operating budget. The weighted standard error for all stations, with current operating procedures, was 19.9 percent. By altering field activities, as determined by the analyses, this could be reduced to 17.8 percent. The existing streamgaging networks in four Districts were further analyzed to determine the impacts that satellite telemetry would have on the cost effectiveness. Satellite telemetry was not found to be cost effective on the basis of hydrologic data collection alone, given present cost of equipment and operation.
Integrated Water Development Project of Gravataí River Basin, Brazil
Authors: Aoki Ricardo
Published: May 2018

The integrated Water Resources Development Project of Gravataí River Basin was prepared by the National Drainage Works Department (DNOS) and the German Agency for Technical Cooperation (GTZ). An attempt was made to use the capacity available in other departments and specialized institutes.

The objective is to provide information for the departments involved in water resources management so as to enable them to establish specific terms for each hydrographic basin to complement the Federal, state and municipal laws.

The basin problems were considered in this work including all aspects related to water resources development.

With these suggestions the specialized department would be able to define their plans for the future taking into account factors that are not within their field of competence, but which should be taken into account in other fields of work .

Conclusions were presented as to flow regulation, flood protection, domestic and industrial wastewater, water supply, irrigation, environmental conservation and navigation.
Water Resources Management in the Semi-Arid Central Valley of California
Authors: Vasconcelos J. J.
Published: May 2018

Hater resource managers in semi-arid regions are faced with some unique problems. The wide variations in precipitation and stream flows in semi-arid regions increase man's dependence on the ground water resource for an ample and reliable supply of water. Proper management of the ground water resource is absolutely essential to the economic well being of semi-arid regions. Historians have discovered the remains of vanished advanced civilizations based on irrigated agriculture which were ignorant of the importance of proper ground water resource management. In the United States a great deal of effort is presently being expended in the study and control of toxic discharges to the ground water resource. What many public policy makers fail to understand is that the potential loss to society resulting from the mineralization of the ground water resource is potentially much greater than the loss caused by toxic wastes discharges, particularly in developing countries. Appropriations for ground water resource management studies in developed countries such as the United States are presently much less than those for toxic wastes management and should be increased. It is the reponsibility of the water resource professional to emphasize to public policy makers the importance of ground water resource management. Applications of ground water resource management models in the semi-arid Central Valley of California are presented. The results demonstrate the need for proper ground water resource management practices in semi-arid regions and the use of ground water management models as a valuable tool for the water resource manager.
Towards Control of an Estuary
Authors: Saeijs Henk L. F.
Published: May 2018

The Delta Project is in its final stage. In 1974 it was subjected to political reconsideration, but it is scheduled now for completion in 1987. The final touches are being put to the storm-surge barrier and two compartment dams that divide the Oosterschelde into three areas: one tidal, one with reduced tide, and one a freshwater lake. Compartmentalization will result in 13% of channels, 45% of intertidal flats and 59% of salt marshes being lost. There is a net gain of 7% of shallow-water areas.

Human interventions with large scale impacts are not new in the Oosterschelde but the large scale and short time in which these interventions are taking place are, as is the creation of a controlled tidal system. This article focusses on the area with reduced tide and compares resent day and expected characteristics. In this reduced tidal part salt marshes will extend by 30–70%; intertidal flats will erode to a lower level and at their edges, and the area of shallow water will increase by 47%. Biomass production on the intertidal flats will decrease, with consequences for crustaceans, fishes and birds. The maximum number of waders counted on one day and the number of ‘bird-days' will decrease drastically, with negative effects for the wader populations of western Europe. The net area with a hard substratum in the reduced tidal part has more than doubled. Channels will become shallower. Detritus import will not change significantly. Stratification and oxygen depletion will be rare and local.

The operation of the storm-surge barrier and the closure strategy chosen are very important for the ecosystem. Two optional closure strategies can be followed without any additional environmental consequences.

It was essential to determine a clearly defined plan of action for the whole area, and to make land-use choices from the outset. How this was done is briefly described.
Utilization of Water Hyacinth for Removal and Recovery of Silver from Industrial Wastewater
Authors: Pinto C L. R. , Caçonia A. , Souza M. M.
Published: May 2018

The water hyacinth (Eichhorniacrassipes) was studied as a pollution monitor for accumulation of silver and subsequent recovery of the element from the plant tissues. After cultivation of the plants for 24 hours in silver solution containing 40 mg/l the plants were harvested, rinsed with tap water and dried at 110°C for 48 hours. The dried material was submitted to pyrolysis and chemical digestion and the silver absorbed by the plant was precipitated, calcinated and recovered in the metal form. The average concentration of silver was found to be 8,000 mg g−1 of dried plant material. An Atomic Absorption Spectrophotometer was utilized for the analysis.

The average concentration of silver recovered from the dried plant material, was 70% of the initial silver concentration of the silver solutions and revealed a purity of 98%.

The water hyacinth has the potential of producing 873/ha/day of dried material and can be used for the production of biogas rich in methane (Wolverton, B.C.; McDonald, R.C.).

After the wastewater treatment, the harvested plants can be used for biogas production and the residual sludge may be utilized for recycling the valuable metal.
Ecotoxicological Effect Indices: A Rapidly Evolving System
Authors: Cairns John , Pratt James R.
Published: May 2018

Ecotoxicology has evolved from a modest number of single species, acute toxicity tests to an integrated system of hazard evaluation for predicting adverse effects of chemicals and complex mixtures on environmental health. The process of screening and regulating chemicals and industrial discharges has improved water quality but has generally not been validated in receiving ecosystems. This deficiency results from the regulation of individual chemicals that rarely occur alone in the environment and from the size of the problem. Many receiving ecosystems have literally hundreds of discharges of complex effluents. Typical single species laboratory tests fail to account for the complexity of ecosystems and the strong interactions that may occur among the component species. Evidence is accumulating that complex test systems such as microcosms and mesocosms can fill this void. Microcosms and mesocosms can be constructed and experiments conducted in a cost-effective manner, and several end points can be measured in complex systems using the standard dose-response paradigm. For example, the current regulation of chlorine discharges is based on three chronic exposures to chlorinated sewage effluent. In a microcosm test, we determined adverse biological effects at nearly an order of magnitude less chlorine (1 μg/1) for the loss of microbial species. To be effective hazard evaluation tools, microcosms and mesocosms must include ecologically meaningful processes and must be useful in making decisions regarding environmental safety and harm. This can only be done with adequate statistical design and intensive sampling. Nevertheless, laboratory ecosystems can be useful in making direct measurements of effects on a large number of interacting species and can be tied to a site-specific problem in a particular ecosystem or can be standardized by using regional type ecosystems as references. By using complex natural communities, the ability to validate test system predictions increases since the test system complexity mimics that found in the real world. Despite hopes that a few sensitive species might be used to make decisions quickly on environmental effects, ecological health will only be maintained when scientists and regulators come to grips with the problem of protecting ecologically important processes as well as sensitive species. This will mean developing tests with increasing environmental realism in which environmentally realistic concentrations of chemicals can be tested without resorting to the use of safety factors or extrapolation from limited data bases. Developing such tests does not mean skyrocketing costs for screening chemicals and effluents, but suggests that regulators and toxicologists will need to deal with new information and learn new skills rather than relying on historically pleasing but ecologically deficient testing programs.
Productivity as a Population Performance Index in Life-Cycle Toxicity Tests
Authors: van Straalen Nico N. , de Goede Ron G. M.
Published: May 2018

Toxicity at the population level is often measured by the intrinsic rate of population increase (rm). In this paper, the biomass turnover ratio (P/B) of a population is introduced as another measure of population performance under toxic stress. An expression is derived by which the intrinsic P/B ratio may be calculated from life-table data. Unlike rm, P/B depends also on the individual growth curve. The theory is exemplified by experimental data on the effect of cadmium on Orohesella cincta (Collembola) from forest soil. The results are compared with seasonal fluctuations of productivity in an unstressed field population. Toxic effects of cadmium appear at a much lower exposure level than would be deduced from the P/B ratio. Some mechanism of compensation seems to be present in that the high natural mortality (by predation) obscures the sublethal effects on growth. This may explain why Collembola can inhabit forest soils which are contaminated to levels far above the no effect level for individual growth.
Nitrogen Transformations and Removal in Waste Stabilization Ponds in Portugal: Seasonal Variations
Authors: Santos M. C. R. , Oliveira J. F. S.
Published: May 2018

Nitrogen transformations that can occur in WSP depend on pond and waste characteristics and are also influenced by climatic factors, like temperature and precipitation. Experiments described have been carried out using a system of three ponds in series: anaerobic, facultative and maturation, treating domestic sewage. In this paper we aim to identify the processes that might contribute to N transformations in each pond and the seasonal variations in the removal of nitrogen and its bioconversion throughout the year.

Results have proved that there was an important organic N removal in the anaerobic pond, mainly due to mineralisation and not exclusively by sedimentation.

Some of the processes of N transformation observed in the ponds were more strongly influenced by weather conditions than others. In some cases, the increase of biological activity that was induced by the increase in air temperature, was masked by reduced precipitation which produced less diluted treated effluents. These climatic factors can explain some of the variations observed along the year, in what concerns nitrogen compounds concentrations.
Microorganism Removal in Waste Stabilization Ponds in Portugal
Authors: do Nascimento M Jenny
Published: May 2018

This study has evaluated the removal of traditional biological indicators of faecal pollution and two new indicators: Pseudomonasaeruginosa and Clostridiumperfringens in waste stabilization ponds which were installed at the waste treatment plant of Loures, at Frielas, near Lisbon.

The removal efficiency for indicator organisms was 10/100 ml in the anaerobic pond A1, except for one of them, and less in A2. In facultative ponds the removal was 10/100 ml while in maturation pond M2 the removal efficiency was higher for traditional indicators than for the new indicators; in pond Ml the removal was less than in M2.
Effects of Maturation on the Characteristics of Wastewater Stabilization Pond Sludges
Authors: Carré J. , Baron D.
Published: May 2018

The physical-chemical characteristics, (pH, Eh, S2−, TOC, NH4+, particulate Kjeldahl nitrogen (PKN), total phosphorus (TP) and PO43−.) of the sludge accumulated in the first of a series of wastewater stabilization ponds nave been studied in two vertical profiles in order to characterize the effects of the maturation of the sludge. The effects on the concentration of faecal indicator organisms and salmonella have also been determined.

The maturation leads to an increased density of the sludge and to the removal of about 80% of the TOC, 70% of PN and of 75% of TP initially present in the fresh sludge.

The concentrations of sulfate reducing bacteria do not change and those of the total coliforms, the faecal coliforms and the faecal streptococci are only moderately modified, as the maximum decrease is 4 log. Salmonellae only are found in the superficial sediment layer, which might indicate their rapid inactivation.
Interpretation of Laboratory-Scale Waste Stabilization Pond Studies
Authors: Wood T.
Published: May 2018

The objective of this paper is to demonstrate the importance of choosing an appropriate mathematical model when analyzing the data from laboratory-scale studies of waste stabilization ponds. Two case studies are presented based on work by Thirumurthi and Nashashibi (1967) and Uhlmann et al (1983), both using semicontinuous methods of experimentation involving the addition of discrete volumes of feed at regular intervals. In both cases the authors have used mathematical models of continuous processes to analyse their results. This paper shows how semicontinuous models can be used in both studies, leading to significant differences in interpretation of the data; in the first case study this relates to the determination of rate constants and, in the second case study, to the determination of an appropriate model to describe hydraulic mixing. Each case study concludes with a discussion of the significance of the semicontinuous interpretation in the context of waste stabilization pond design.
Attached-Growth Waste Stabilization Pond Treatment Evaluation
Authors: Shin H. K. , Polprasert Chongrak
Published: May 2018

This study investigated the feasibi1ity of improving waste stabilization ponds (WSP) performance through the addition of attached-growth media in the pond water. An artificial media consisting of fine strings of polyvinylidene chloride was employed as an attached-growth media in the laboratory-scale and pilot-scale experiments. Better removal of organic, nutrient and suspended solids were obtained in the attached-growth waste stabilization ponds (AGWSP). The AGWSP were found to be rather stable against increased hydraulic loadings. However, the fecal coliform die-off in the AGWSP units were not significantly different from those of the control units without attached-growth media.
Irrigation Reuse of Pond Effluents in Developing Countries
Authors: Bartone C. R. , Arlosoroff S.
Published: May 2018

The large-scale reuse of sewage for irrigation, often without adequate safeguards, is commonplace in many arid and semiarid regions of the world. A UNDP/World Bank global research project has reviewed available epidemiological data and formulated a risk model to evaluate sanitary control options for effluent irrigation. The study concluded that wastewater treatment processes that effectively remove all or most of the pathogens in wastewater provide a major or total reduction in the negative health effects caused by raw wastewater reuse. Furthermore, the study found the recommended criteria for effective wastewater treatment for irrigation reuse in developing countries to be, in order of priority: (1) maximum removal of helminths; (2) effective reduction in bacterial and viral pathogens; and (3) freedom from odor and appearance nuisances (i.e., reduction of BOD). Multicell stabilization ponds are suited to meet all three criteria. Research sponsored by the UNDP/World Bank project has shown that well-designed and operated multicell stabilization ponds achieve virtually total removal of helminths and a greater than 99.99 percent reduction of enteric bacteria. Waste stabilization ponds can produce an odor-free effluent rich in nutrients and attractive for agricultural use. Most suitable in hot developing countries, ponds are a particularly robust, flexible, and almost fail-safe treatment system having low construction and operation costs. Research is now focusing on management and policy issues required to effectively achieve controlled irrigation reuse.
Deep Wastewater Reservoirs in Israel – I: Limnological Changes following Self-Purification
Authors: Dor Inka , Kalinsky Iris , Eren Jahob , Dimentman Chanan
Published: May 2018

Ma'ale Kishon, one of the largest reservoirs storing wastewater for irrigation in Israel, has surface area of 1.3 km2, depth of 9 m and volume of 12 million m3. Secondary effluent enters the northern basin and after a mean retention period of 6 weeks, flows into the southern one. Due to this two basins structure, changes taking place during the water storage can be detected. The differences between the two basins were quantitatively studied by an interdisciplinary team.

The sanitary, physico-chemical and biological variables indicated an improvement in water quality, leading to an increased ecosystem stability and a safer environmental performance. These results suggest that deep reservoirs of the type here described serving for wastewater disposal and reuse may have a wide application also in other countries having warm, subtropical climates.
French Experience in the Operation and Maintenance of Wastewater Treatment Lagoons
Authors: Vuillot M. , Boutin C. , Dupuis M. F.
Published: May 2018

A general survey of maintenance requirements and problems of wastewater lagoons has been conducted in France with a view to preparing an operation manual for plant owners and local operators. An outline of the pond maintenance situation in France is given, and the main information and recommendations contained in the manual are presented in this paper.
High Load Process Using Yeasts for Vinasses of Beet Molasses Treatment
Authors: Malnou D. , Huyard A. , Faup G. M.
Published: May 2018

Bulky plants are required to treat industrial effluents using conventional processes (settlement tanks, activated sludge, etc.). New techniques are being sought to reduce the size of the plants.

The use of microorganisms, such as yeasts, in aerated reactors makes it possible to process effluents with very high volumetric loads and to produce a valorizable biomass.

Despite their high salinity and COD concentration, yeasts can be used to process sugarbeet molasses liquors with volumetric load exceeding 80 kg COD.m−3.d−1, removing 70 % of the COD.

The improvement in the quality of the biomass produced and the design of new types of reactor will allow this high-performance process to be developed into an interesting alternative method of treating concentrated industrial effluents.
Quantification of Odour Problems Associated with Liquid and Solid Feedlot and Poultry Wastes
Authors: du Toit A. J.
Published: May 2018

To prove the validity of an odour complaint, a standard evaluation procedure, whereby selected odour compounds are monitored, is proposed for use by Health authorities. The technique determines the dispersion of specific compounds from a point source. Odour threshold limits, determined by specialist odour panels, are used to evaluate the seriousness of the problem. Thereafter, individual waste handling systems are isolated as possible point sources of offensive odours. If dispersion studies and high odour compound concentrations prove the validity of a complaint, individual sites are investigated to determine the identity of the malfunctioning handling phase(s) of a specific treatment system. Results of various parameters are related to offensiveness in this procedure. The practical and objective nature of this technique makes it particularly suitable for application in semi-rural environments where agricultural activities have impinged on residential areas.
Performance of Aerated Lagoons in Treating Wastewater from Small Communities
Authors: Narasiah K. S. , Morasse C. , Larue M.
Published: May 2018

Aerated lagoons are used in developing and developed countries to treat domestic and industrial wastewater especially from small communities. They represent a reliable method of biological treatment capable of producing satisfactory effluent throughout the year. They are preferred to several other treatment processes like the activated sludge because of the simplicity of the overall system, less need for trained operator assistance and very competitive overall cost of wastewater treatment. In Québec where there are some 1400 small municipalities this method of treatment is found to perform satisfactorily, notwithstanding the extreme temperature variations. The objective of the present study is to evaluate the performance of this method of waste stabilization from the point of view of organic removal, retention time, power requirement and nutrient removal without chemical coagulation. An existing treatment plant with aerated lagoons was used for the study. The results show that a summer retention time of about 8 days can produce an effluent having 20-25 mg/L of BOD, 20 mg/L of SS and 2-3 mg/L of total phosphates without coagulant addition.
The Ability of Lettuce, Rye Grass and Barley to Reduce the Nutrient Salt Content of Wastewater from Fish Farming
Authors: Pettersen B. W.
Published: May 2018

In order to find methods to reduce the nutrient salt content of waste water from aquaculture systems, crop and field plants such as lettuce, rye grass and barley were cultivated in water coming from a pilot size fish farming unit for rainbow trout. Growth rates for rye grass and barley were less than 50% of the maximum growth rates obtained under field conditions in Denmark, and lettuce could not grow in the recirculating water. By adding carbon dioxide to the recirculating water until slightly above the equilibrium concentration, growth rates for rye grass and barley improved to maximum rates under field conditions, and lettuce of good quality was produced. Mass balances for P and N indicate that fertilizing value of waste water from 25 kg rainbow trout is sufficient for cultivation of 20 m2 rye grass at maximum growth rate.
Design Considerations for a Nitrification-Denitrification Process Using Two Fixed-Bed Reactors in Series
Authors: Jimenez B. , Capdeville B. , Roques H. , Faup G. M.
Published: May 2018

This paper concerns design considerations (kinetics and hydraulic criteria) for a biological nitrification-denitrification attached culture process for sewage treatment.

The treatment system is composed of two submerged filters. The first one, an anoxic reactor, denitrifies and retains wastewater suspended solids. The second one oxidizes organic carbon and ammonia nitrogen.

It was found that the main parameter for the system is the recycle ratio since it sets the real hydraulic detention time in reactors and determines the quantity of nitrogen available to the denitrification process.
Benefits of Including Unaerated Zones in Nitrifying Activated Sludge Plants
Authors: Dold P. L. , Marais G v. R.
Published: May 2018

In nitrifying activated sludge systems several practical advantages accrue from inclusion of unaerated (anoxlc) zones. Accepting the general activated sludge model proposed by the IAWPRC Task Group, as modified by Dold and Marals (1985), simulation studies on nitrifying and nltrlfylng-denltrlfylng systems demonstrate the advantages of the latter with respect to (1) reduction in dally oxygen requirements, (2) reduction in effluent nitrate load, (3) elimination of pH control, (4) alleviation of the stringency in D.O. control, and (5) reduction in the required peak aeration capacity.
Anaerobic Treatment of an Apple Processing Wastewater
Authors: Dold P. L. , Sam-Soon A. , Palmer I. H. , Marais G v. R.
Published: May 2018

The new generation of anaerobic digestion systems provide a high level of performance under optimal conditions (~ 37°C). However, in practice many influents will be at lower temperatures - heating of digesters presents problems, particularly in developing countries where technical backup is limited. This paper reports on a study of the treatment of a low/medium strength apple juicing waste in an upflow anaerobic sludge blanket reactor (UASB) at temperatures Less than optimal (25°C and 30°C). Maximum loading rates of approximately 12 and 16 kg COD m−3 d−1 were attained at 25°C and 30°C, respectively, for Influent concentrations in the range 2500 to 5000 rag COD ℓ−1. The comparative treatment capacity is In accord with the reported temperature sensitivity of mesophilic anaerobic processes. Formation of pelletised (granular) sludge enabled high upflow velocities and low hydraulic retention times.
Examination of the Zinc Cementation of Cadmium in Aqueous Solutions
Authors: Gould J. P. , Escovar I. B. , Khudenko B. M.
Published: May 2018

The kinetics of the cementation of cadmium by zinc have been studied over a range of solution pH values and initial cadmium concentrations. The kinetics were interpreted in terms of a model postulating a transition from a migration controlled mechanism with consequent half order kinetics to a diffusion controlled regime following first order kinetics. The conditions under which each mechanism was found to apply were consistent with the model in which the immediate reductant was hydride ion generated by the interaction of hydrogen ions with the zinc. The reaction stoichiometry was remarkable in that conditions were observed under which more than the theoretical one mole of cadmium per mole of zinc could be reduced. This was ascribed to the electrolysis of water by the induced electrochemical system. A lag in both cadmium cementation and zinc dissolution was observed in many runs. The zinc dissolution was found to commence about 25% sooner than cadmium cementation, a fact ascribed to the establishment of the reducing electrochemical system.
A Study on the Use of Bipolar-Particles-Electrodes in Decolorization of Dyeing Effluents and Its Principle
Authors: Ding Zhou , Min Cai Wei , Hui Wang Qun
Published: May 2018

This paper studies the use of bipolar-particles-electrodes in the decolorization of dyeing effluents. Treatment of highly colored solutions of various soluble dyes (such as direct, reactive, cationic or acid dyes) and also samples of dyeing effluents gave rise to an almost colorless transparent liquid, with removal of CODcr and BOD5 being as high as over 80%. The method is characterized by its high efficiency, low energy consumption and long performance life. A discussion of the underlying principle is given.
Prediction of Soluble Nickel Removal by Activated Sludge Using Free Metal Ion Concentrations
Authors: Nielsen Jeppe S. , Hrudey Steve E. , Cantwell Frederick F.
Published: May 2018

Batch isotherm studies using spiked sewage samples containing a range of total soluble nickel concentrations typical of municipal sewage strongly suggested that it is the free (i.e. uncomplexed) nickel ion that is sorbed by activated sludge. Equations relating nickel uptake by activated sludge to free nickel ion concentrations and the extent of complexation in untreated sewage were developed and applied. Predicted and measured nickel removals generally agreed to within ± 30%.
Fate of Toxic Organic Compounds in Activated Sludge and Integrated PAC Systems
Authors: Weber W. J. , Jones B. E. , Katz L. E.
Published: May 2018

The addition of powdered activated carbon (PAC) to activated sludge treatment systems to enhance removal of specific toxic organic compounds from wastewater was evaluated. Nine organic compounds encompassing a range of solubility, volatility, biodegradability, and adsorptive properties were studied. Kate and equilibrium investigations were conducted to quantify the removal mechanisms of volatilization, biodegradation, biosorption, and carbon adsorption. Results from steady-state bioreactor studies showed that the addition of less than 100 mg/ℓ powdered activated carbon to the influent did not enhance the removal of the biodegradable target compounds investigated: benzene, toluene, ethylbenzene, o-xylene, chlorobenzene, and nitrobenzene. Significantly improved removals of the poorly degradable and non-biodegradable compounds 1,2-dichlorobenzene, 1,2,4-trichlorobenzene, and lindane occurred at influent powdered carbon concentrations in the 12.5 to 25 mg/ℓ range. Influent powdered carbon concentrations of 100 mg/ℓ effected overall removals of greater than 90%. The addition of powdered activated carbon not only reduced effluent concentrations but also reduced the amounts of the volatile compounds stripped to the atmosphere.
A Critical Evaluation of Microbial Product Formation in Biological Processes
Authors: Rittmann B. E. , Bae W. , Namkung E. , Lu C.-J.
Published: May 2018

A critical evaluation of the characteristics of soluble microbial products (SMP) indicates that SMP is comprised of many different types and sizes of molecules and is biodegradable. A portion of SMP is formed at a rate proportional to the rate of substrate utilization (UAP), while the rest is formed at a rate proportional to the concentration of active biomass (BAP). These characteristics are incorporated into a mathematical model that includes the following components: substrate utilization and biomass growth according to Monod kinetics, SMP formation kinetics in proportion to substrate utilization rate and to biomass accumulation, and SMP degradation according to a semi-empirical multi-component degradation model. The SMP formation/degradation model successfully describes the fractional conversion of substrate into SMP, including the observed trends of increasing conversion at high and low sludge ages. In addition to activated sludge, the model is applied to anaerobic treatment and to biofilm processes.
A Lake Eutrophication Management Model
Authors: Somlyódy L.
Published: May 2018

An eutrophication management optimization model (EMOM) was developed and applied for Lake Balaton - a typical shallow water body - in order to establish a short term control strategy. It incorporates a stochastic load response model which was derived from the Monte Carlo type usage of a four-compartment, four-box dynamic lake eutrophication model after developing synthetic time series generators for forcing functions. EMOM also includes a planning mode nutrient loading model which accounts for various uncertainties and stochastic effects. Major control options are phosphorus precipitation on existing sewage treatment plants and the construction of pre-reservoirs. Among alternative objective functions and models formulated, here a linearized expectation - variance model is discussed which captures the major stochastic features of the problem. The “optimal” short term strategy is worked out for Lake Balaton. In the frame of a sensitivity analysis the importance of various physical, chemical, biological and economic parameters is evaluated as regarding for eutrophication management.
A Comparison of Simple Methods for Estimating the Mass Flow of Fluoride Discharged into Rivers
Authors: Van Craenenbroeck W. , Marivoet J.
Published: May 2018

In order to follow the long term evolution of the pollutant discharge pattern, and to detect changes in the situation, information about the discharge mass flow is necessary. First, the paper deals with the behaviour of the fluoride concentration in the river Meuse. Data are presented for the stretch Remilly (France) to Keizersveer (Netherlands), and the evolution over the period 1970–1984 is described. Data from waste waters and tributaries are discussed, and a dominating fluoride source is identified. In the second part, a linear first order equation is proposed for fitting the C-Q data at Liège (Belgium). Five methods for estimating the mean fluoride mass flow of the discharge are compared and discussed. The weighted least squares method is proposed for further use. It makes use of data from a routine measuring station, and gives the possibility to estimate a natural concentration which is constant over the studied period 1970–1984. The thus obtained value of 0.19 mg/l is equal to the mean fluoride concentration upstream of the discharge point. The estimated discharge mass flow is about 6 t/d, and this value remained constant since 1979.
Coagulation of Two Different Kinds of Surface Water before Inlet into Lakes to Improve the Self-Purification Process
Authors: van der Veen C. , Graveland A. , Kats W.
Published: May 2018

Part of the drinking water demands of the city of Amsterdam and the surrounding district are met by abstraction from nearby Lake Loenderveen that is fed by two different kinds of surface water. The lake itself is subject to rainfall, evaporation and seepage. It acts partly as a stockpiling reservoir (about 2 weeks) and partly as a self-purifying medium (retention time about 100 days).

The design and management of the lake are such that a high degree of mixing of the inflowing water is obtained and an almost constant water quality, which greatly facilitates subsequent treatment to obtain high quality drinking water.

To combat eutrophication the nutrient-containing water that enters the lake is dephosphated. After a number of years working with an experimental and simplified method in the lake itself, a highly efficient new coagulation and settling plant was constructed. This has been in operation since 1984. The improvements in the quality of the lake water are discussed in this paper. In addition to a considerable reduction in the phosphate content (and that of other nutrients), improvements were registered in a number of other water quality parameters (DOC, heavy metals, colour c.a.).

A similar coagulation and settling system is also used to treat one kind of surface water that is fed into the adjacent Loosdrecht Lakes during dry summer spells.

These lakes are of great environmental importance; they are also unique features of the landscape. Pretreatment of the water that flows into the lakes has a substantial effect on the water quality. A monitoring system has been set up to check the resulting improvement.
Pollution and Eutrophication in the Venice Lagoon
Authors: Cossu R. , de Fraja Frangipane E. , Degobbis D. , Orio A. A. , Andreottola G.
Published: May 2018

To reduce the effect of the “high water”, which involves mainly the City of Venice, a project is underway to install barriers in the three port channels which connect the Venice lagoon to the Northern Adriatic Sea. To have a basis on which to gauge any observed effects in the water quality as a consequence of the reduction of the exchange of water between the lagoon and the open sea, a survey on the most polluted area of the lagoon was carried out over the period of a year. The following parameters were determined: pH, temperature, salinity, transparency, dissolved oxygen, ammoniacal nitrogen, orthophosphate, zinc and total coliforms. The results, compared to those obtained from previous studies, show that situation improved for ammoniacal nitrogen, zinc and coliforms and remained fairly constant for the other parameters. The inner zones of the lagoon are much more exposed to eutrophication as a consequence of a lower circulation of water and higher accumulation of nutrients. Release from sediments appears to play an important role in controlling the water quality in the shallow areas. Frequent algae blooms have been observed during spring and summer seasons. There is no evidence of an attenuation of eutrophic phenomena in recent years.
Salinity Control of Interstate Waters in Argentina
Authors: Moyano Amílcar
Published: May 2018

Water salinity control in interstate basins is exercised by means of treaties. Such is the case of the Colorado River in Argentina by the Treaty of 26 October 1976. However, environmental restoration of soil, flora and water requires constant adjustment, which can be made by agreements that render this possible, or by political decisions that will prevent conflicts among the states.
Summary of Results from the Swedish Project ‘Environment/Cellulose'
Authors: Södergren A. , Bengtsson B.-E. , Jonsson P. , Lagergren S. , Larson Å , Olsson M. , Renberg L.
Published: May 2018

The biological effects of effluents from pulp industries, especially from bleaching processes, on aquatic ecosystems were studied in a joint biological/chemical project field consisting of several sub-projects. The principal study was devoted to the effects of biologically active chlorinated organic compounds.

A receiving body of water for pulp bleach plant effluents at the Gulf of Bothnia was chosen for the three year study. Near the effluent outlet the fish biomass was low, and the species composition of the fish community had changed. Perch (Perca fluviatilis L.) exhibited reduced reproduction and disturbed physiology in all parts of the receiving body of water. The effluent also affected the diversity, biomass and distribution of invertebrates and plants. To further study the effects, fish and benthic-living organisms were exposed in the laboratory to sediment from the receiving water and to various mixtures of bleach plant effluents. The level of extractable organic chlorine (EOC1) of the perch decreased along a gradient from the effluent outlet towards the open sea. In sediment outside the Swedish coast, the level of EOC1 and the occurrence of compounds related to bleach mill effluents indicated a distribution of such substances over large areas.
Control of the Phosphorus Level of Effluent in the Treatment of Forest Industry Waste Waters
Authors: Väänänen P.
Published: May 2018

Pulp and paper mill wastewaters are nutrient deficient, BOD5:N:P may be as low as 100:1:0.2. Now that purification requirements have been tightened, the activated sludge process seems to be most commonly used treatment method. The conventional activated sludge process requires BOD:P ratios of 100 to 0.6 resulting in a need for P addition and hence in a possible increase in the P-level of the effluent.

In Finland and also in some other areas phosphorus removal is of great importance in the prevention of eutrophication of watercourses. There are several methods to control phosphorus level, such as biological phosphorus removal, running of the process under starvation of phosphorus, tertiary (chemical) treatment and simultaneous precipitation of phosphorus. This paper lists possible treatment methods and presents more closely chemical treatment using simultaneous precipitation by ferrous sulphate. The results are based on both pilot and full-scale experiments in two kraft pulp mills.

The study showed that phosphorus concentration can be reduced to a level of 1.2 mg/l (tot.P) by adding ferrous sulphate to the aeration basin in activated sludge treatment of kraft pulp mill wastewaters. Ferrous sulphate has, also, a slight positive effect on the sludge properties e.g. sludge settleability.
Treatment and Characterization of Biological Sludges from the Pulp and Paper Industry
Authors: Kyllönen H. L. , Lappi M. K. , Thun R. T. , Mustranta A. H.
Published: May 2018

A research project on characterization and treatment of sludges from the pulp and paper industry was initiated at the Technical Research Centre of Finland (VTT) at the beginning of 1986. The research is included in a research programme on non-waste technology. The aim of the work is to develop optimal treatment processes for pulp and paper mill sludges.

The first experimental phase, currently underway, is focused on investigations of various ways of releasing bound water from the sludge, with particular emphasis on developing correlations between measurable sludge properties and dewatering behaviour. Activated sludges of different origin have been subjected to various chemical, thermal and enzymatic treatments. The effects of these conditioning treatments on the properties of the sludges have been characterized by different analytical methods, for example, by measuring changes in the specific resistance to filtration, the amount of water bound in different ways, the particle size distribution, and the chemical composition of the sludges. Results of these experiments are discussed.

The interpretation of the effects of the treatment methods studied was hampered by deviating properties of sludges. A treatment effective for one sludge under certain conditions did not have a similar effect on the dewatering properties of some other sludge. Thermal treatment of sludges proved to be the most effective method for breaking water binding, although the most influential factor could not be identified. Ultrasonic treatment had a clear effect on the particle size distribution and settling of the sludges, but not on dewaterability, and proved to be closely related to the sludge concerned. The enzymes tested had no significant effect on the dewatering characteristics of the sludges. The results obtained so far will be used for designing an optimal sludge treatment process in future work.
The Methanogenic Toxicity of Bark Tannins and the Anaerobic Biodegradability of Water Soluble Bark Matter
Authors: Field J. A. , Leyendeckers M. J. H. , Sierra Alvarez R. , Lettinga G. , Habets L. H. A.
Published: May 2018

The principal methanogenic toxins of bark soluble matter were identified as the tannins. The tannins, which were measured with a selective tannin adsorbant called polyvinylpyrrolidone, accounted for about half of the aqueous extractable COD of tree bark. The 50% inhibitory concentration of bark tannins averaged approximately 600 mg COD L−1 (350 mg tannin solids L−1). The toxicity caused by the resin fraction of bark was demonstrated not to be very important to the methanogenic toxicity of aqueous extracts. While tree resin compounds were found to be very toxic to methanogenic bacteria, the solubility of the resin fraction was very poor due to the low natural pH during the aqueous extraction. Additionally, those compounds aqueous extracted from tree resin at the natural pH were not as toxic as all the tree resin compounds solubilized by alkali and supplied at similar concentrations. Anaerobic biodegradability results indicated that 30 to 50% of the bark water soluble COD can be acidified to methanogenic substrates during short term digestion. Pine and birch bark water soluble COD acidified up to 70% after long term batch digestion of 7 weeks. The high level of bark aqueous extract UV absorbance elimination by anaerobic digestion and the appearance of intermediates indicated that at least some of the bark phenolic compounds were included in the methanogenic substrate.
Effects of Pulp Mill Effluent on a Baltic Coastal Fish Community
Authors: Neuman E. , Karås P.
Published: May 2018

Atundance and species composition of fish, including early stages, were studied along a gradient from a Bothnian pulp mill producing tleached kraft. Close to the outlet, the density of fish was very low and the recruitment drastically reduced. Further away, tiomass increased to a high level in a zone characterized ty dense populations of cyprinids, mainly roach, and ruffe. Other common Baltic species, e.g. herring, perch and sand-goty, occurred in subnormal densities. Compared to the cyprinids, the recruitment of these species was disturbed in much wider areas, which is considered to te a consequence of their larval tiology. The populations of at least perch and sandgoty must largely te tased on immigration. The effluent impact on the fish communities seems to te due to a comtination of its eutrophicating, toxic and repelling properties; the low transparency of the water may also te important.