bluuebunny/crossref_metadata_2025 huggingface dataset:
Enlargement of Sewage Treatment Plants for Nitrification by Use of Subsequent Rotating Biological Contactors
Authors: Nyhuis G.
Published: May 2018

The surface-specific nitrification performance of Rotating Biological Contactors (RBC) has been improved considerably by the use of new techniques. Maximum nitrification rates of 3.3 g/m2×d (10 °C) were achieved, which cannot be approached with any other known procedure. This high oxidation efficiency is achieved with Rotating Biological Contactors by using two new measures:A large degree of separation of carbon degradation and nitrogen oxidation through filtration of the waste water before the subsequent nitrifying RBC stage, whereby the environmental conditions for the nitrifying bacteria are improved, especially in respect of an optimised supply of oxygen.Periodic reversal of the direction of flow in the RBC stage which is constructed as a cascade. This measure allows the attainment of a uniform thickness of nitrifying bacteria growth in all the compartments, which has a particularly advantageous effect in the case of unavoidable surges in load.

Because of the low production of excess sludge in the nitrification stage, a subsequent stage for separating solids is not necessary. In this paper experiences with the upgrading of a full scale rotating biological contactor plant and the measuring results from an enlarged oxidation pond installation are summarized.
Advanced Chemical Treatment with Flocculation in Pipes
Authors: Latvala A.
Published: May 2018

At the beginning of 1988 there were in Finland about ten small chemical wastewater treatment plants that were using flocculation in pipes instead of flocculation basins. This method consists of Me+++-chemical feeding, mixing, flocculation and sedimentation. Chemicals were fed into the suction openings of the wastewater pump, which is used for rapid mixing and also for pumping wastewater flow to the sedimentation basin. In the sedimentation sludge blanket sedimentation in deep vertical sedimentation basins was used. The sedimentation basin can also be used as sludge storage, if it is made sufficiently large. This method has been found especially suitable for small wastewater treatment plants, because it needs little labour and is cheap to build and to use and it is not affected negatively by fluctuations in the flow. The construction costs of this system in Finland have been about 50 % of those involved in traditional chemical package plants. The limitations of this method are its weakness in removing soluble organic load and its inability to oxygenate or remove nitrogen. However, a biological unit designed to cope with these limitations is under development.
Intermittent Cycle Extended Aeration System (ICEAS R) for Small Wastewater Treatment Plants
Authors: Khararjian H. A. , Callaway W. H. , Cardinal P. , Meany J.
Published: May 2018

Many municipalities and industrial plants with small quantities of wastewater are facing challenges with providing economical treatment strategies. They require simply designed and operated processes which give high quality effluent.

One such process is the Intermittent Cycle Extended Aeration System (ICEAS R). This is a variant of the activated sludge biological process which allows continuous inflow of raw wastewater and intermittently discharged influent. It provides flow equalization, biological oxidation and sedimentation with decanting of supernatant in a single tank. The process can be operated on any cycle duration based on the required degree of treatment. Each cycle consists of aeration, sedimentation and decantation phases. The aeration phase can be operated on an oxic/anoxic mode for the purpose of nitrification/denitrification and biological phosphorus removal.

To date, there are more than 100 plants worldwide and 25 within the U.S.A. that are built and operating successfully. High degrees of BOD, suspended solids and nitrogen removal are obtained with the plants. Most of the small plants require minimal operating personnel, generally one or two, for continuous operation.
Upgrading a Municipal Activated Sludge Plant for High-Rate Biological Nutrient Removal
Authors: Randall Clifford W. , Waltrip David , Wable Milind V.
Published: May 2018

A full-scale activated sludge plant was modified for high-rate BNR operation at minimal cost. Three different processes (A/0+, A2/0+ and UCT) were studied at BSRTs varying from 4 to 14 days and HRTs of 2 to 6 hours. Onset of BPR was almost immediate without addition of special seed. Good phosphorus removal was obtained with all three processes except for periods of extremely high influent flows or high nitrate recycle to the anaerobic zone. However, because of high process phosphorus loadings resulting from high influent concentrations and sludge processing recycles, effluent TP concentrations were typically in excess of 2 mg/L. Nitrogen removal was excellent when nitrification could be maintained and nitrate recycle was sufficiently high. All processes yielded excellent nitrogen removals during warm weather, but complete nitrification could not be maintained during winter conditions. Implementation of a statewide phosphate detergent ban resulted in a 40 per cent decrease in the influent wastewater concentrations. Following the ban, the UCT process was shown to be capable of consistently meeting the Virginia nutrient discharge standards of 10 mg/L TN and 2 mg/L TP during the growing season.
Upgrading Wastewater Treatment Plants with Anaerobic Selectors
Authors: Tracy K. D. , Hong S. N.
Published: May 2018

The anaerobic selector of the A/0™ process offers many advantages over conventional activated sludge processes with respect to process performance and operational stability. This high-rate, single-sludge process has been successfully demonstrated in full-scale operations for biological phosphorus removal and total nitrogen control in addition to BOD and TSS removal. This process can be easily utilized in upgrading existing treatment plants to meet stringent discharge limitations and to provide capacity expansion. Upgrades of two full-scale installations are described and performance data from the two facilities are presented.
Renovation of an Extended Aeration Plant for Simultaneous Biological Removal of Nitrogen and Phosphorus Using Oxic-Anaerobic-Oxic Process
Authors: Moriyama Katsumi , Sato Kazuaki , Harada Yoshinobu , Washiyama Kazuo , Okamoto Koich
Published: May 2018

The effect of the oxidation reduction potential (i.e., ORP) control system on the simultaneous removal of nitrogen and phosphorus, utilizing the oxic-anaerobic-oxic process, was investigated. A full-scale wastewater treatment plant which was designed as an extended aeration process was modified for this process to study. The optimum ORP at the first basin for the simultaneous removal was 125 mV in this experiment. In the first oxic basin the nitrification reaction and the denitrification reaction occurred simultaneously to maintain the optimum level of the ORP value. The averaged values of the effluent of this process were 1 mg/l of total nitrogen (T-N), 0.5 mg/l of total phosphorus (T-P) and 5 mg/l of BOD respectively. It was also clearly shown by the statistic analysis that the ORP control was more effective in comparison with the control of dissolved oxygen (DO) concentration for the operating method of this process. Additionally, it was supposed that the simultaneous nitrification and denitrification using the ORP control system was a reliable nitrogen removal system for renovating the conventional activated sludge process because the hydraulic retention time of the first basin used in this study was equal to that of the conventional process.
Tertiary Waste Water Treatment with Flotation Filters
Authors: Kiuru H. J.
Published: May 2018

Tertiary waste water treatment has been usually carried out by adding filtration after an activated sludge process, which can be fitted with pre- or simultaneous precipitation for removal of phosphorus. Filtration is operated either as a mechanical unit operation for upgrading the removal of suspended solids only, or as contact filtration where the precipitation of phosphorus is boosted with a minute dose of trivalent iron or aluminium.

Instead of using conventional downflow filters, tertiary treatment can also be carried out with flotation filters where flotation is accomplished in the head above the filter, necessary for filtration in any case. The possibility of using flotation between secondary clarification (sedimentation) and filtration, when it is needed, results in a very good load bearing capacity and in a high degree of removal of solids.

This means that excellent operational results can be achieved with an almost complete reliability in all operational circumstances at a very reasonable cost. Long experience in Finland from a medium size (30 000 pe) activated sludge plant with simultaneous precipitation fitted with flotation filter tertiary treatment in 1984, shows that values of BOD7 ≤ 5 mg/l, Ptot ≤ 0.3 mg/l NH4-N ≤ 1 mg/l and of suspended solids ≤ 5 mg/l can be continuously achieved, in the treatment of municipal waste water where total nitrification is applied.
Development of a Two-Stage Treatment Plant for Extensive Nitrogen and Phosphorus Elimination
Authors: Bahre G. , Firk W. , Gassen M.
Published: May 2018

The report describes low-cost development and design of a two-stage wastewater treatment plant for 90,000 PE to achieve the highest possible degree of phosphorus and nitrogen elimination. The receiving water body of the treatment plant is a small watercourse fed almost exclusively by treated wastewater. A significant improvement in the water quality of this watercourse is planned. In particular, the performance of the wastewater treatment plant will need to be enhanced. The plant operator, the Erft River Board, organized a competition to attract solutions for an appropriate development of the plant from several consultants. Apart from embodying the concept of extensive wastewater treatment, designs were expected to preserve the existing infrastructure of the two-stage treatment plant as far as possible.

Following selection of the most suitable design, the intended process technology is currently being tested in a pilot-scale plant. Planning envisages advanced wastewater treatment processes, including enhanced biological phosphorus removal, chemical precipitation/flocculation, nitrification and denitrification and combined coagulation/filtration. The pilot-scale investigations are carried out in close co-operation between the water authorities, the plant operators, the consultant, and a university institute of sanitary engineering.

The paper presents the design and first results of the pilot-scale investigations in terms of the parameters BOD5, COD, phosphorus, ammonia and nitrate.
Upgrading of Small Municipal Wastewater Treatment Plants with Heavy Dairy Loading by Introduction of Aerated Submerged Biological Filters
Authors: Ødegaard Hallvard , Rusten Bjørn
Published: May 2018

Most of the dairies in Norway discharge their wastewater to the municipal sewers. Insufficient knowledge about the organic load coming from the dairies, has resulted in inadequate design and organic overloading in the municipal wastewater treatment plants of this category. Several of the plants that originally based their biological process upon RBC as the bioprocess, have experienced mechanical breakdown of the RBC system. The submerged biological filter (SABF) has been introduced as an alternative biofilm method that may be used when broken down RBC-plants (or activated sludge plants) are to be upgraded. The paper describes results from pilot-plant experiments on dairy waste when the SABF is used for pretreatment, as well as results from plants in practice where the SABF is used for combined treatment of the dairy and municipal wastewater. It is shown how pretreatment in a balancing tank may be established, and results from the use of an alternative floating biofilm media are given.
Upgrading Oxygen Transfer in the Activated Sludge Process
Authors: Pelkonen M.
Published: May 2018

The objectives were to get some information on the variation of the alpha factor and to study factors affecting oxygen transfer efficiency in fine-bubble aeration. Results from a 5 week continuous operation of a batch aeration column process show that the variation of the alpha factor was considerable in the aeration basin, especially at the inlet end. The variation follows a diurnal rhythm and the weekly variation is much smaller. The off-gas method was used to examine factors affecting oxygen transfer in process conditions. Regression models were constructed to describe the transfer process both on a semitechnical scale and on a full scale. The most important factors are the specific air flow rate, the respiration rate and the DO concentration. The enhancement in OTE through the respiration rate and the DO concentration is due to a biological mechanism. To optimize the transfer process it is necessary to maintain a high respiration rate and a sufficiently high DO concentration.
Sediment Movement into the Combined Trunk Sewer No. 13 in Marseille
Authors: Laplace D. , Sanchez Y. , Dartus D. , Bachoc A.
Published: May 2018

The AGHTM, a French technical association, supports a research program on the transfer of solids into sewer networks. It aims to better understand how sediments develop in trunk sewers and what can be their contribution to wet-weather pollutant discharges. The priority is given, during the first phase, to observation, especially inside the combined trunk sewer n° 13 in Marseille. Various parameters such as sediment depth, water level, flow velocity fields, sediment particle size or mechanical characteristics are measured. Certain conclusions have been reached. For example, we have been led to form some assumptions, such as:

– the volume of sediment increases substantially, principally at the entry points, during the first rainfall events, it decreases during the three days following rain, and seem to become stable after several months; – the solids deposited in the sediment are much larger than those which make up the most part of pollutant discharge during wet weather.
Constructed Wetlands for Wastewater Treatment: The New Zealand Experience
Authors: Bhamidimarri R. , Shilton A. , Armstrong I. , Jacobson P. , Scarlet D.
Published: May 2018

The use of constructed wetlands which mimic natural marshlands, represents an innovative approach to wastewater treatment. They make use of diverse ecological mechanisms to renovate wastewater. They are inexpensive to construct and operate with minimal energy requirements. Unlike the conventional technologies, wetlands provide low volumetric reaction rates and therefore are suitable for small-scale applications.

The majority of constructed wetlands in New Zealand are used for the treatment of domestic wastewaters from small communities for secondary treatment and pathogen removal. There are over 20 constructed wetlands in New Zealand receiving wastewater flow rates ranging from 7.5m3/day to around 4500m3/day. Both surface-flow and subsurface-flow wetlands are used. The performance data from three wetland systems treating septic tank effluents are presented and their treatment efficiences are discussed.
Water Pollution Simulation over a River Basin Using a Computer Graphic Model
Authors: Chen Sun
Published: May 2018

A Computer Graphic Model (CGM) was realized on a personal computer for the purpose of river water pollution simulation and planning. With the aid of common software AutoCAD, a color map of a complex river system was established and a suite of graphic symbol blocks such as pollution source, water intake, wastewater treatment plant etc. was designed to fit the needs of basin pollution management and planning. A person can insert, move/remove or modify these symbol blocks in the CGM of the river basin freely. While a new idea is confirmed, a simulation program POLSIM (written with AutoLISP) can be started which redraws the river with different width and color by the mean flow quantity and water quality. The result of a case study and a group of photographs is presented. The methodology of CGM makes the planning process of basin water pollution control easier, visual and interactive. CGM is a friendly tool to link the decision maker, planner and system analyst with active graphics.
Management of a Complex Water Supply Network for the Stabilization of Aquatic Habitat
Authors: Cubillo Francisco
Published: May 2018

The detailed study of the needs and feasibility of the maintenance of the flow regimes established in the river reaches located downstream from dams is an issue which is appearing more and more often as part of the basic considerations for hydraulic and environmental planning as well as for the exploitation of hydraulic resources. The management of a complex system of reservoirs, rivers and waste treatment plants, such as in the case of the Canal de Isabel II of Madrid, regards the needs and feasibility factors as parts of the overall hydraulic planning program of its watersheds. The complexity of Madrid's hydraulic system and the influence that erroneous conclusions could exert upon determining the discharge regimes has prompted the Canal de Isabel II to adopt more technical aids than commonly used for these types of studies. It was necessary to integrate a wide range of mathematical models for water quality, resource management and instream flow, so that ultimately, each alternative could be contrasted with its corresponding economic and social costs.
A Nutrient Model for a Lake with Time-Variable Volumes
Authors: Kuo J. T. , Wu J. H.
Published: May 2018

A total nutrient model for a completely mixed water body is often used for lake eutrophication analysis. In the model, the assumption of constant volume of a lake is usually made, i.e. the inflow to the lake is equal to the outflow. However, for some lakes which have significant difference between inflow and outflow during a studying period (usually larger than the detention time), the assumption of constant volume is no longer valid and could cause error in solution. This research has developed a more general model which solves the nutrient mass balance equation for the lake with time-variable volumes. In the model, the method of power series is used to obtain the solution. By merely taking the first few terms in power series (e.g. fewer than 15 terms), the approximate solution is very close to the exact solution. In this way, both computer time and numerical error can be minimized compared to the numerical solution. This newly developed nutrient model is applied to Chen-Chin Lake in southern Taiwan for phosphorus modeling in eutrophication study.
A Sediment Transport Model for Lake Ketel (The Netherlands): A Tool for Water Management
Authors: Blom G. , Toet C.
Published: May 2018

In Lake Ketel (The Netherlands) the bottom sediment is contaminated with heavy metals and organic micro pollutants. To simulate the effect of management options on transport of polluted bottom sediment STRESS-2d, a 2-dimensional model for sediment transport, resuspension and sedimentation in shallow lakes was adapted for Lake Ketel. Model development, calibration and simulation results are discussed in some detail, with emphasis on the effects of uncertainty in parameter values.
Modeling Effects of Tidal Barrier Closure of Venice Lagoon
Authors: Orlob G. T. , Bale A. E. , Rajbhandari H. , Malagoli M.
Published: May 2018

As a combined result of land subsidence and sea level rise in the vicinity of the City of Venice there has been a net decrease in the difference between the mean elevations of land and sea of about 30 centimetres over the past century. This has resulted in an increased incidence of flooding in Venice with occasional disastrous consequences, as in November 1966 when storm and tide conditions combined to flood the Piazza San Marco to depths exceeding one metre. Among the solutions proposed to solve the flooding problem is a modular tidal barrier that is designed to close the three major entrances to the shallow lagoon in which Venice is situated. Because the lagoon is highly eutrophic and circulation is driven primarily by the tide in the Adriatic Sea, there is concern that operation of the barriers could exacerbate an already serious problem of pollution. The lagoon currently receives the untreated waste water from Venice with an organic loading equivalent to more than 400,000 persons during the tourist season, industrial discharges from the Port of Marghera, and non-point accretions of nutrients from adjacent agricultural areas. Preliminary investigation of the effects of the proposed barrier scheme using mathematical hydrodynamic and water quality models suggests that prolonged isolation of the lagoon from the sea, if this should become necessary for flood protection, may enhance primary production and induce unfavorable water quality conditions. This paper presents results of this investigation and offers suggestions for further refinement and application of the models to assist in the environmental impact assessment which must be performed prior to barrier construction.
A Network Algorithm for the Optimum Operation of Urban Drainage Systems
Authors: Neugebauer K. , Schilling W. , Weiss J.
Published: May 2018

The objective is to route sewage through a combined sewer by means of a real time control system. The task is formulated as a mathematical network optimization problem. The sewer system is simplified to be a set of linearly operating nodes and arcs. Tests indicate that the results obtained are comparable to linear programming solutions. However, much larger systems can be handled. The algorithm is fast enough to have it applied on AT-PC's for real world sewer systems.
Expert Support System for Cost Modeling and Evaluation of Wastewater Treatment
Authors: Galil N. , Levinsky Y.
Published: May 2018

New technological conceptions in wastewater treatment are based on analysis of sequences including physico-chemical and biological treatment processes. The proposed expert support system (ESS) enables the examination of entire treatment sequences, each including several treatment stages and processes for sludge treatment, going through all the kinetics, mass balances and specific calculations for each separate process. The ESS calculates treatment costs as a function of different technical or economical parameters. It was found that parameters of pollution concentration, typical to municipal wastewater, as suspended solids, organic matter and ammonia, exert direct linear influences on the treatment cost. The analysis of treatment sequences revealed that the more efficient is the paniculate organic matter removal, achieved by primary physico-chemical processes, mainly using hydrated lime, the lower will be the entire sequence treatment cost. The paper demonstrates the use of the proposed ESS in analyzing different conceptions of process combinations. The ability to analyze entire sequences may impart a significant higher level in considering new wastewater treatment technologies.
Operational Experience with an Anoxic Selector Treating Rendering-Plant Wastewaters
Authors: Chudoba Jan
Published: May 2018

The activated sludge process for the treatment of rendering-plant wastewaters was designed and constructed as a two-stage system. The treatment plant did not ensure the secondary effluent standards demanded by the local water authorities. Ammonia-nitrogen was reduced by 40 % only due to the synthesis of the biomass and ammonia volatilization. Nitrification and denitrification did not take place. Filamentous bulking occurred during summer periods, which resulted in an effluent of poor quality. In order to decrease the discharge of filamentous sludge and nitrogen into the recipient, the original two-stage system was reconstructed into a one-stage system with an anoxic selector. The anoxic selector suppressed filamentous bulking only partially, so that the values of SVI are now around 150 ml/g. This is because 100-200 mg/l of available COD gets from the selector into the first nitrification tank operated as a completely mixed system which is known to support the bulking. An internal recirculation of about 800 % of the influent ensures denitrification efficiency as high as 90 %. The reconstructed activated sludge plant removes BOD5-by 98 %, COD by 96 %, and total nitrogen by 91 %. Specific rates of nitrification vary from 0.8 to 1.4 mg/g.h in the first nitrification tank and from 0.4 to 1.0 mg/g.h in the second nitrification tank. In the latter tank, nitrification is inhibited by low pH values. Specific rates of denitrification in the anoxic selector vary from 1.3 to 7.3 mg/g.h (as NO−3-N).
Development of Design Criteria for the Chemical Precipitation Process Applied in Cracow Wastewater Reclamation System
Authors: Rybicki S. M. , Kurbiel J.
Published: May 2018

The results of investigation on coagulation as tertiary treatment of secondary effluent in the water reuse process for industrial application are presented. The investigations were carried out at the municipal wastewater plant in the city of Cracow.

The experimental model has been operated continuously under dynamic flow conditions; the paper describes the construction of the model as well as the experiences gained during its operation. The investigations which were carried out in the laboratory batch tests are also described.

The studies were conducted using alum, ferrous sulphate, lime, an alum combined with lime and ferrous sulphate combined with lime doses. The best effectiveness of orthophosphorous removal was found for alum /96.2 %/ and ferrous sulphate combined with lime /84.2 %/. The best results of permangante COD removal were reached for ferrous sulphate /52 %/ and ferrous sulphate combined with lime /51.3 %/.

In the paper the suitability of experimental models and procedure for experimental data evaluation in development of design criteria are presented.
Anaerobic Treatment of Yeast Plant Effluent in Fermentation Reactor System Compared with an Upflow Filter System
Authors: Apolinarski M. E.
Published: May 2018

A laboratory-scale study was conducted on a two-stage fermentation reactor system and an upflow anaerobic filter system at several loading rates and hydraulic retention times. Feed substrate was wastewater from yeast production plant. The hydraulic residence time for first-stage fermentation reactor was 7 days and loading rate was in the range of 1.1-2.3 kg COD m−3d−1. The hydraulic residence time for second-stage fermentation reactor was 3.5 days and loading rate was 0.8-1.0 kg COD m−3d−1. Upflow anaerobic filter was operated at hydraulic retention time ranging from 5 to 2 days and loading rates ranging from 0.5 to 4.5 kg COD m−3 d−1. Despite shorter residence time, higher purification effects have been achieved for upflow anaerobic filter than for I-stage digestion reactor. For anaerobic upflow filter 61%-68% of COD reduction has been achieved at loading rates 3.5-4.0 kg COD m−3 d−1 and retention time of 2 days. For both systems in comparison the relationship between purification effects and volumetric organic load has been established. Amount of generated fermentation gas has been measured and composition of that gas has been analysed. Methane content in fermentation gas was in the range of 6l%-64%, hydrogen sulfide content was 0.5%-1.9%. Laboratory experiments were carried out at the temperature 33°C.
The Use of a Turbulent Pipe-Flow for Rapid Flocculation of Precipitate in the Electroplating Wastewater Treatment
Authors: Kurbiel J. , Sapulak A. , Schade H.
Published: May 2018

The paper presents the results of an experimental pilot study on advanced flocculation of metal hydroxides that are precipitated from electroplating wastewater during pH-adjustment. A pipe-flocculator with a turbulent flow, to ensure proper mixing conditions, was used instead of a classical flocculation tank. The results of the study indicated a high efficiency of the process. The flocculation proceeded within 50-100 seconds, which was much less than is required during classical flocculation. Application of a pipe-flocculator results also in reduction of both capital and operating costs of the wastewater treatment plant.

In conclusions, important conditions, which are indispensable if pipe-flocculation is to be used, were formulated.
Anaerobic Treatment Kinetics: Discussers' Report
Authors: Harper S. R. , Suidan M. T.
Published: May 2018

A discussion of principles guiding the experimental elucidation of microbial growth and substrate utilization kinetics, and the development of mathematical models for anaerobic wastewater treatment systems, is presented. Recent developments in the areas of anaerobic treatment microbiology (including biomass characterization), biochemical mechanisms, microbial growth dyamics, reactor hydrodynamics, and mathematical modeling approaches are presented and explored.
Anaerobic Wastewater Treatment in Downflow Stationary Fixed Film Reactors
Authors: Kennedy K. J. , Droste R. L.
Published: May 2018

Design features and performance of the downflow stationary fixed film reactor for anaerobic wastewater treatment are reviewed. Media characteristics, feed characteristics and loading rates found to provide rapid start-up and maximum treatment efficiency are discussed. It is concluded that the reactor is a useful research tool for studying anaerobic treatment. The reactor is not as sensitive to waste characteristics as other second generation anaerobic reactors. The reactor is able to handle wastes with high suspended solids content and provide efficient treatment with a minimum clogging potential. DSFF operation is simple and stable; however, loading rates attainable in this reactor are not as high as those attained with other processes due to lower biomass retention capacity.
Planning and Implementation of Water Reuse Projects
Authors: Asano Takashi
Published: May 2018

As the demand for water increases, water reuse has become an increasingly important source of water in many parts of the world, particularly in arid and semi-arid regions. In this paper, categories of water reuse are identified, and planning methodologies and economics for wastewater reclamation and reuse are discussed, emphasizing implementation. Special attention is paid to tertiary treatment systems which produce essentially pathogen-free effluent for variety of uses including irrigation of parks, school yards, and golf courses as well as groundwater recharge in the urban environment.
Long-Range Planning for Water Reuse in the City of Los Angeles
Authors: Sheikh Bahman
Published: May 2018

While new sources of affordable potable water for Los Angeles will likely decrease or be unavailable in the future, sources of readily usable reclaimed water will double over the next decade. For many non-potable uses (e.g., landscape irrigation, industrial cooling, toilet flushing), reclaimed water can replace potable water, thereby making equivalent volumes of potable water available. Groundwater recharge with reclaimed water can further augment potable water supplies in significant volumes. Quantitative goals for water reuse were derived by comparing projected water demands with predicted dependable supplies. These goals are to reuse 40, 70, and 80 percent of the total effluent by the years 2010, 2050, and 2090, respectively. In this planning study, several water reuse concepts were evaluated for near-, mid-, and long-term application. For the near-term, several immediately implementable water reuse projects are recommended, involving landscape irrigation, industrial cooling and groundwater recharge. For the mid-term, massive groundwater recharge in San Fernando Valley and in Central and West Coast Basins is recommended. For the long-term, potable reuse and/or groundwater recharge appear to be the best options.
Residual Faecal Contamination on Effluent-Irrigated Lettuces
Authors: Vaz da Costa-Vargas S. M. , Mara D. D. , Vargas-Lopez C. E.
Published: May 2018

The health risk posed by effluent irrigation in a semi-arid area of Portugal was assessed. The residual contamination found on lettuces spray-irrigated with the effluent from a conventional trickling filter plant was compared to that of locally marketed lettuces and to the ICMSF (1974) standards. The 2-year study indicated initially high levels of faecal indicator bacteria on lettuces, but after irrigation ceased, the restricting climatic conditions sufficed to decontaminate them to local market quality within 5 days when no salmonellae could be detected. Although high, E.coli I levels were within the tolerance range of the ICMSF standards suggesting negligible excess exposure of consumers to faecal contamination from the effluent-irrigated lettuces.
Wastewater Reclamation Technologies and Monitoring Techniques
Authors: Odendaal P. E.
Published: May 2018

The paper deals with technologies for the direct reuse of treated municipal wastewater. The choice of reclamation technologies is determined by the quality of the wastewater, quality criteria for the reuse applications, reliability, operational considerations and the extent of control over the total treatment sequence. Catchment quality control as well as flow and quality equalisation should be regarded as first steps and an integral part of reclamation technology. Biological treatment is of primary importance, and special attention is given to the benefits for reclamation of activated sludge processes with high sludge retention times, and to biological nitrogen and phosphorus removal. Further unit processes discussed are chemical coagulation and flocculation, solids separation, disinfection, activated carbon, reverse osmosis, stabilisation and sludge management. In discussing monitoring techniques, attention is given to instrumentation, analogue and digital transmission, flow measurement, continuous measurement of selected parameters, sampling, maintenance, visual observation, and biomonitoring. In the conclusion, examples are given of various applications of using secondary effluent with little or no tertiary treatment, and the point made that considerable impact on the conservation of water supplies can be made without resorting to complicated and expensive technology.
Demonstrating Residential Water Conservation and Reuse in the Sonoran Desert: Casa del Agua and Desert House
Authors: Karpiscak Martin M. , Brittain Richard G. , Gerba Charles P. , Foster Kennith E.
Published: May 2018

Single-family homes are being used to demonstrate and research water conserving and reuse techniques and technologies. These facilities can provide real-world data as well as public information and educational programs. The installation of water-conserving fixtures, rainwater harvesting, and graywater reuse systems and storage can reduce the requirements for potable water by 50 percent. Casa del Agua and Desert House show that the science of conserving resources can be balanced with the art of designing quality desert dwellings.
Dual Distribution Systems: The Public Utility Perspective
Authors: Johnson William D.
Published: May 2018

Diminishing water resources are a worldwide problem. Many countries face serious water supply issues in the near future.

The United States has not escaped the problem of providing adequate water for its needs. Rapid population expansion in semi-arid locales, and growth in areas where groundwater resources are sensitive to saltwater intrusion have forced local officials to search for alternatives to satisfy a growing demand for water.

The City of St Petersburg, Florida, developed and is operating one of the world's largest urban water reuse systems. The program has been very successful in reducing potable water demands. The city has learned a great deal during the past fourteen years that the system has been in service.

The purpose of this paper is to share the history of the development of the St Petersburg Water Reuse System and what has been learned during its operation.
Reclaimed Water – An Urban Water Resource
Authors: Okun Daniel A.
Published: May 2018

The population in urban areas is growing rapidly; from 30% in 1950 to about 50% at the turn of the century. In 35 years time, the number of large cities (greater than one million) will double and the population living in them will triple. Most large cities are already facing water supply problems and these will increase in the future. Water reclamation for nonpotable reuse for urban irrigation, industry, toilet-flushing, cooling, construction etc. can reduce the demand on limited fresh water resources. Many urban areas around the world have already used this approach to meeting problems of increased water demand.
Strategies for Upgrading from Primary Treatment to Nutrient Removal at the Sandefjord Sewage Treatment Plant
Authors: Rusten Bjørn , Storhaug Ragnar
Published: May 2018

Different strategies for upgrading the Sandefjord primary treatment plant for nutrient removal have been evaluated. This plant is characterized by dilute wastewater, large flow variations and low wastewater temperatures. Phosphorus removal was evaluated based on full-scale tests at the plant. Nitrogen removal in submerged biological filters was evaluated based on literature data. Cost figures indicate that sewer rehabilitation, in order to reduce the flow and increase the influent wastewater concentrations, will be a good investment.
The Introduction of Nitrogen and Phosphorus Removal Technologies for Decreasing Pollution of the Elbe River in Czechoslovakia
Authors: Wanner Jirí , Kos Miroslav
Published: May 2018

A short state-of-the-art-review in nutrient removal technologies is given and problems connected with nutrient removal in the activated sludge process enumerated. The present level of BOD and nutrient load to the Elbe in the Czech Basin and possible means of improvement are discussed. Seven municipal wastewater treatment plants, planned to be built in 1990-2000, are briefly described. The total capacity of these plants represents about 280000 kg BOD5/d and 29000 kg TKN/d.
Pollution of the Outer Oslofjord
Authors: Baalsrud Kjell
Published: May 2018

The Outer Oslofjord has recently been subject to concern.

1. The Inner Oslofjord. Covers an area of 193 km2, is 160 m deep and is separated from the Outer Oslofjord by the narrow Drøbak sound with a sill depth of less than 20 metres. This part of the Oslofjord constitutes an enclosed body of sea water, sensitive to pollution, receiving sewage from approximately 650,000 inhabitants. In spite of modern sewage treatment, the fjord still suffers torn eutrophication problems resulting in reduced oxygen in the deep water, and areas of anoxic bottom water. The fjord is an important recreation area.

2. The Outer Oslofjord. Recent findings indicate that eutrophication is slowly increasing. An increasing eutrophication of the Outer Oslofjord wil also increase the need (and cost) of better sewage treatment in the Inner Oslofjord.

3. The North Sea. The quality of the water in the Oslofjord area is also dependent on the water it receives from the Skagerrak. The Skagerrak water will periodically receive polluted water from the southern North Sea and Kattegat. When these episodes coincide with water renewals between the Oslofjord and the Skagerrak, the fjord will receive polluted water from other countries. The Oslofjord water will in turn discharge into the Skagerrak, but due to the general circulation pattern, this will mainly influence the Norwegian south-east coast.
Nutrient Removal in a Short Retention Time Sewage Treatment Plant
Authors: Karlsson Ingemar
Published: May 2018

Chemical treatment of sewage water is today often considered as a method for phosphorus reduction and used in combination with biological treatment. The experience in Scandinavia, however, shows that chemical treatment alone gives beside a good phosphorus removal also a high BOD reduction. Due to the very low investment cost for such a process it has been adapted in Scandinavia as an alternative to biological treatment. Where the demand is for greater sewage treatment the most feasible method is to complement the chemical precipitation process with a compact biological treatment.

In Sweden the dominating post (and also the simultaneous) precipitation process has in many plants been replaced by a chemical pre-treatment process, because with pre-precipitation most of the organic matter is coagulated and extracted already in the primary clarifier. The energy demand in the biological process will decrease. The organic matter in the sludge will increase, which in an anaerobic digester means more digester gas.

The unloading pre-precipitation effect can also give advantages for nitrification. The important BOD/TKN ratio is decreased. It is possible to build up a high sludge age and to upgrade a plant without tank expansion to a nitrifying plant. Pre-precipitation is normally not influencing the readily degradable BOD, which is about 25% of the total BOD and therefore a perfect electron donor for pre-denitri-fication is still available.

The pre-precipitated sludge contains 75% of the organic matter in the sewage and can by hydrolysis be converted to readily degradable organic matter, which presents a valuable carbon source for the denitrification process. The hydrolysation process can be performed by, for instance, anaerobic treatment or heat treatment. This paper will review experiences from full-scale applications as well as pilot plant and laboratory studies.
The Optimization of Ground Water Supply System in Shi Jiazhuang City, China
Authors: Xueya Lin , Yuesuo Yang
Published: May 2018

This paper established a response function of groundwater level using the principle of superposition formed a response matrix which combined the simulation model of groundwater flow system and the optimization model of groundwater supply system. The calculation was carried out by micro-computer. Two methods were used to determine the unit pulse value so as to calculate more accurate response coefficients. Based on the hydrogeologic conceptual model of the study area, a management model for optimization of groundwater supply system was established under the conditions of not only meeting the increasingly growing need of water supply but also controlling or eliminating the various hazards caused by overpumping of groundwater, and a practical, feasible and comprehensive decision making plan was also put forward for Shi Jiazhuang city.
The Behaviour of Vinasse Constituents in the Unsaturated and Saturated Zones in the Botucatu Aquifer Recharge Area
Authors: Gloeden E. , Cunha R. C. A. , Fraccaroli M. J. B. , Cleary R. W.
Published: May 2018

Vinasse has been widely replacing chemical fertilizers in sugar cane plantations as a source of nutrients, mainly potassium. Despite its value as a fertilizer, which has already been shown, there are very few publications about the mobility of its constituents as well as their effect on groundwater quality.

In a sugar cane plantation located on the Botucatu aquifer recharge area, a research project has been developed to determine the dynamics of the constituents of vinasse through the unsaturated and saturated zones, aiming at defining the agronomic rate of vinasse irrigation in order to preserve the groundwater quality.

Geological and hydrogeological surveys were carried out utilizing data from geophysical methods (electromagnetism and electroresistivity), boring and piezometers.

The area wasdivided into three plots where vinasse was applied at rates of 150 and 300 m3/hectare.

A monitoring net was installed after the hydrogeological characterization of the site, consisting of monitoring wells, multilevel piezometers, tensiometers, suction and pan lysimeters, which allow the evaluation of the water flow and solute transportation through the unsaturated and saturated zones.

This paper shows the preliminary results of the monitoring and the methodology used.
Subsurface Soil and Water Pollution by Diesel Fuel at Boždarevac Railway Station Near Belgrade and Remedial Measures
Authors: Vujasinovic Slobodan , Ivan Matic Docent
Published: May 2018

An excessive pollution of ground water and the hydrogeologic environment by naphtha and its derivatives spilled on the surface has been recorded in Yugoslavia. The similar accidents in Serbia (Obrenovac, Užička Požega, Beograd -Makiš, Beograd-Danube railway station, Leskovac, Boždarevac, etc.) have increased in number in the last several years. Transportation of naphtha and its derivatives, either by road or river, from the refineries to the consumers is obviously contributing much to the environmental pollution hazard. For the wide range of use and the specific effect on ground water, this pollutant can be taken for one of the first order. This paper discussir a case example.
Incinerator of Chlorinated Hydrocarbons Solid Wastes
Authors: Setti H.
Published: May 2018

Fifteen years ago our Company bought an old factory of chlorinated products. Later our Company found that solid chlorinated residues had been thrown in to a completely inadequate soil.

After having determined the sites contaminated several solutions were thought through: artificial deposits, old granite mines, etc., none of them adequate. Finally the incineration process was chosen and approved by authorities. Today the installation is built and operates according to requirements.
Risk Assessment Methods for Establishing Clean Closure Levels
Authors: Riggenbach J. D. , Streeter R. A. , Hess S. C.
Published: May 2018

Establishment of clean closure concentrations for low levels of hazardous constituents in soils, ground water, and other environmental media by assessing risks to human health and the environment is a tool that is being used with increasing frequency. The four-step process sanctioned by the U.S. Environmental Protection Agency (EPA) includes: 1) hazard identification, 2) exposure assessment, 3) toxicity assessment, and 4) risk characterization. This paper describes the methodology and applies it to the closure of a hazardous waste surface impoundment in Florida. To date, the closure process has taken nearly five years and, pending the EPA's and Florida Department of Environmental Regulation's (FDER's) final approval, will result in clean closure of a small facility that has spent in excess of $450,000 U.S. during this period for removal of 516 cubic metres of sludge and other solids. If clean closure is approved, as is concluded to be protective of human health herein, the facility owner stands to save $275,000 U.S. that is estimated would be required to monitor ground water and to maintain an impermeable cap for the 30-year post closure period currently required under U.S. and Florida regulations.

The risk assessment discussed in this paper began when soil samples collected after excavation of 516 cubic metres of sludges, soils, and other solids showed that the preliminary soil closure levels sanctioned by the FDER for chromium and nickel had not been achieved. Continued excavation would have cost a minimum of $50,000 to $100,000 U.S. (in 1988 dollars) and still may not have reached closure levels for these two metals. It is concluded in this paper that the maximum levels of chromium and nickel remaining onsite after remedial excavation (2.1 and 3.7 mg/kg, respectively) do not pose a risk to human health, and that the agency could raise the allowable closure level for these two metals from the current values of 1.1 and 0.70 mg/kg to these maximum values.