bluuebunny/crossref_metadata_2025_split huggingface dataset:
Operation of the Soreq Wastewater Treatment Plant with a Single-Stage Nitrification-Denitrification Activated Sludge System
Authors: Arueste G. , Farchill D. , Goldstein M. , Gruber Y. 
Published: May 2018

The Soreq Biological wastewater Treatment Plant has been in operation almost one and a half years. The treatment performance and operational data obtained during the first year of full-scale operation, following the running-in period, are detailed in this paper as four consecutive seasonal operating periods. The results achieved have demonstrated the efficiency, in carbonaceous matter removal and the nitrification-denitrification processes, of the single-stage system, operated without primary treatment.
The influence of various operating parameters on the efficiency of the biological process and on the sludge settleability have been analysed. Two anaerobic tanks, preceding the anoxic zone of the biological reactors, were brought into operation at the end of March 1988. The influence of their addition to the biological process train has also been included herein.
Effects of Temperature and pH on the Settleability of Activated Sludge Flocs
Authors: Çetin F. Dilek , Sürücü Gülerman 
Published: May 2018

In efficient and economical treatment of wastewaters,the settleability of activated sludge is of prime importance. Efficient settlement in the secondary sedimentation tank is required, both to keep the desired effluent quality and to sustain the necessary amount of microorganisms in the aeration tank. On the other hand, the settleability of microorganisms in the secondary clarifier is very dependent on the physiological and biochemical nature of activated sludge flocs, which are determined by the conditions of the aeration tank.
In this research, effects of temperature and pH of aeration basin on settleability of activated sludge were studied. Settleability was measured by zone settling velocity and sludge volume index (SVI). Five different temperatures and four different pH values were operated in the aeration basin. It was found that the settleability of activated sludge is greatly affected by these two parameters.
Sewage and Solids Disposal: Are Processes Such as Ocean Disposal Proper? The Case of Rio de Janeiro (Brazil)
Authors: Jordão Eduardo P. , Leitão Jorge R. 
Published: May 2018

In developing countries, as is the case of Brazil, solutions proposed for sewage and sludge treatment and disposal must meet not only public environmental demands and obey proper legal regulations, but also take into account the availability of funds for new investments and operation of existing systems.
Brazilian federal regulations allow ocean disposal of sewage and solids, according to certain water quality criteria and specific standards.
On the other hand, federal regulations require that submarine outfalls must be studied by means of an Environmental Impact Assessment, and that a Report on the Environmental Impact be produced. Such studies must demonstrate that the site will be protected and that ocean disposal will not impair the environment and the beneficial uses, such as fisihing, recreation, navigation, or propagation of marine life.
The State of Rio de Janeiro has monitored its Ipanema Submarine Outfall since 1974, one year prior to going into operation. Present flow is 6m3/sec (140 mgd) of bar-screened domestic sewage. The submarine outfall is a 2.4m diameter concrete pipe, 4.3 km (2.7mi) long, and discharges at a depth of 27m (89ft). The paper presents and discusses existing regulations and data on the seawater monitoring program which is still in practice, having produced more than 90,000 analyses. Discussion covers the period 1974 - 1988, and shows that no adverse ecological impact has been noted on the marine ecosystem.
Mesophilic and Thermophilic Digestion of Municipal Sludge in a Deep-Shaft U-Shaped Bioreactor
Authors: Tran F. T. , Tyagi R. D. 
Published: May 2018

Aerobic digestion of primary and secondary sludges was studied in airlift bioreactors at mesophilic and thermophilic temperatures. The experimental studies were conducted with a laboratory U-shaped airlift reactor (operating volume = 23 1) and in a pilot U-shaped airlift reactor with an operating volume of 1150 1. In the laboratory reactor, at a lower temperature (6°C) and with a concentrated feed (3 to 4% solids) consisting of primary and secondary municipal sludge, a 30% VSS reduction was achieved with a hydraulic retention time of 2.5 days. A VSS loading rate of 8.2 kg VSS per m3 per day was achieved. This loading is comparable to that obtained in a pure-oxygen sparged mixed reactor.
In the pilot plant reactor at mesophilic temperatures (31 to 33°C), a VSS loading rate of 7.9 kg VSS per m3 per day and a VSS reduction of 33% were achieved with a hydraulic retention time of four days.
A Compaction-Granulation Process Turns Municipal Sludge into a Valuable Fertilizer Component
Authors: Wolstenholme Philip 
Published: May 2018

To prepare dried municipal sludge material for use by the fertilizer industry, Ocean County Utilities Authority, New Jersey needed a process to increase the size of their sludge particles to between 1 and 3 millimetres. Several processes were evaluated during the planning and design phases of the project. The most cost-effective and reliable process was pressure agglomeration by compaction with a roll press, followed by granulation and screening of the compacted material. This process was tested with a sample of the Authority's digested sludge, which had been dried in a laboratory-scale evaporator. Fullscale compaction and granulation test equipment was used at a laboratory in West Germany to confirm the feasibility of the process and to develop data for the design of the project.
As a result of its “innovative” approach to sludge processing, the United States Environmental Protection Agency (EPA) qualified this $60 million project for special funding. The project is nearing construction completion and due to be commissioned in spring of 1990.
Solidification of Electroplating Wastewater Treatment Sludges with Cement
Authors: Rosa Cláudio Jair , Alem Sobrinho Pedro 
Published: May 2018

At the São Paulo Metropolitan Area, the sludge resulting from treatment of electroplating industry wastewater is inadequately disposed of, generating environmental hazards. A possible way to solve this problem is the cementation of this sludge before disposal.
From July,1986 to March, 1987, the authors developed laboratory tests on cementation of electroplating wastewater treatment sludges. Performed at the laboratories of Escola Politécnica of the University of São Paulo and of CETESB, tests were conducted with three types of cement produced in Brazil - CPC - Portland Cement, POZ-pozzolanic cement and CAF - blast furnace cement. The tests had the following steps:characterization of electroplating industry wastewater treatment sludge and study of the sludge - cement mixtures;preparation of sludge - cement mixtures with water/cement ratios of 0.3, 0.5 and 0.7;measurements of mixture consistency with Casagrande soil mechanics equipment;determination of leaching quality and resistance to compression of solidified specimen at the ages of 7 days, 28 days and 90 days;analytical determination of the sludge cement mixture;test for solubility in water at the age of 90 days;analytical determination of cyanide and heavy metals in the cure water of specimen.
Results showed that solidification with cement is an efficient technology for the fixation of toxic metal ions such as Cd, Hg and Pb and other metals such as Cr, Ni, Cu or Zn present in large concentrations in electroplating wastewater treatment sludges. With the only exception of Al+++ the other metallicions determined in the leachate showed concentrations below drinking water standards. As to mechanical resistance after 90 days, the sludge - cement mixtures presented a performance similar to that of structural concrete.
Kinetics and Modelling of Aerobic and Anaerobic Film Growth
Authors: Capdeville B. , Nguyen K. M. 
Published: May 2018

Our fundamental studies of the kinetics of growth and substrate removal by aerobic and anaerobic biofilms have shown that the process comprises six phases : the latent, dynamic, linear, decrease, stabilization and detachment phases. During these experiments we also observed:-steady state functioning in the liquid bulk from the end of the dynamic phase. At this point a very thin pseudo-thickness of biofilm was observed (50 µm maximum).-steady state functioning relative to the observed biofilm mass, reached in the stabilization phase, the corresponding thickness being generally several hundred microns.
To explain this phenomenon we suggest a new biofilm modelling hypothesis, based on physiological aspects, which consists of defining two types of bacteria : active bacteria (Ma) responsible for substrate removal and characterized by a specific growth rate (µo), and inert or deactivated bacteria (Md) which play no role in the removal process but are responsible for the observed accumulation of biofilm. Using this hypothesis, it is possible to modelize the dynamic and linear phases of growth of total biofilm dry matter (Mb) and carbon substrate removal kinetics.
This model enables the exponential growth rate (µo), the accumulation rate (K) and the maximum quantity of active bacteria (Ma)max to be calculated. In another series of experiments, we studied the influence on these parameters of several factors which affect growth, such as the carbon substrate concentration provided by the feed (So) and the dissolved oxygen for the aerobic biofilms.
The results demonstrate that the biological constants are strongly dependent on (So). The same is true for the volumetric substrate removal rate(kov), which shows that the process always depends on the reaction. Thus we have established that the substrate metabolization reaction occurs at the biofilm-liquid interface, and that it is preferable to use thin biofilms for an attached culture industrial process.
This has been done by optimizing the surface and volume properties of new granular materials called OSBG (Optimized Support for Biological Growth). Initial results, notably for three-phase fluidized bed carbon removal, show that it is possible to eliminate very high carbon loading (10 to 15 kg TOD.m3.day−1) under very stable conditions with a very small quantity of active biomass (0.5 D.W. m). In addition, excess sludge production is relatively low and respirometric studies performed in situ with a gas phase mass spectrometer confirm the very high catabolic activity of thin biofilm.
New Developments in Complete Nitrogen Removal with Biological Aerated Filters
Authors: Rogalla Frank , Bourbigot Marie-Marguerite 
Published: May 2018

Biological aerated filters combine bacterial degradation of pollution by fixed biomass with physical filtration in a single reactor.Several full-size plants with the BIOCARBONE process have established the compactness, ease of operation and high removal rates achievable with this advanced treatment system. Based on large-scale industrial experiences, a new biofilter design offering simplified operation and increased performance is presented.
Design data for carbon and nutrient removal were collected during extensive pilot tests. Hydraulic conditions and pollution loadings were varied in order to optimize the biological and operational parameters of the filter. Carbon and ammonia oxidation as well as denitrification and suspended solids retention could be achieved with an overall hydraulic retention time of two hours.
Treatment of Distillery Wastewater Using an Anaerobic Downflow Stationary Fixed-Film Reactor: Performance of a Large Plant in Operation for Four Years
Authors: Racault Y. 
Published: May 2018

The results of the first four years' operation of a downflow submerged packed bed reactor treating distillery waste with a COD of 30 g/l (95 % in soluble form) are presented. The digester contains 4300 m3 of packing, and is operational six months a year. It is one of Europe's largest units using this technique.
After a few problems with fixing the biomass on start-up, organic loading has been regularly increased, reaching an average of 6 kg COD/m3.d during the 2nd year and 10 to 12 kg COD/m3.d during the 4th year, with soluble COD reductions of 90 to 95 %. The biomass released into the treated effluent was in the region of 0.15 kg SS/kg COD eliminated in the latter campaign. Overall performance in the 2nd, 3rd and 4th seasons are presented and discussed. The stability of digestion was studied over the whole of the 2nd and 4th seasons using measures of VFA at various levels within the reactor. Tracer study was conducted at the end of 2nd year to characterize the hydraulic behavior of the reactor. Results indicated a flow pattern close to a complete mixing and dead space was in the region of 20 % of liquid volume.
Optimization of Nitrogen Removal in Small Activated Sludge Plants
Authors: Heduit A. , Duchene Ph , Sintes L. 
Published: May 2018

In France, many small sewage treatment plants are of the activated sludge/extended aeration type and, generally, only receive a part of their nominal organic load. They are mostly equipped with surface aerators whose Standard wire Aeration Efficiency is in the range 1.3-1.9 kg 02 kwh−1. Consequently the sludge age and the supply of oxygen are sufficient to obtain a large elimination of nitrogen from domestic waste water even when the sludge temperature is low.
However the concern is with the optimizing of the nitrogen treatment by the nitrification of ammonia in the aeration basin whilst avoiding any parasitic denitrification in the clarifier.
Amongst other investigations, 4 small domestic wastewater treatment plants were studied over several months. A number of adjustment modifications were imposed on them in order to optimize the elimination of nitrogen : The final concentrations to be reached were : N-NH4− lower than 5 mg.l−1 and N-NO3− lower than 3 mg.l−1.
The daily operating time of the aerators depends on the received load, the sludge concentration and the oxygenation capacity. When the works are under-loaded, the non-operational periods of the aerators should be as long as 1 1/2 and 2 hours in order to achieve the nitrates reduction. When the load is higher, the time required to attain anoxia after the shutdown of the aerators is shorter and the length of the non-operational periods can be reduced. These field experiments have allowed an evaluation of the tolerances around an optimum adjustment of the aeration operation : a reduction of 5 to 10 % of the daily aeration time may bring about an increase in the residual concentration of Kjeldahl nitrogen which reaches 10 rag.1−1. Conversely, sludge losses may take place in the clarifiers if the daily aeration time is increased by 5 to 10 % in the case of completely mixed basins equipped with slow vertical shaft aerators, and more than 15 % in the case of oxidation ditches (better denitrification probably due to the continuation of the current after stopping the rotors). The sludge concentration should be kept within fairly tight limits (± 0.5 g.1−1). It is however essential to rectify the aeration adjustments during the seasons : a rise in the sludge temperature of 10°C generates an increase in the total oxygen demand by 3 to 5 %.
The particular case of plants with anoxic zone ahead is finally discussed.
Sludge Handling and Disposal at Small Wastewater Treatment Plants in Norway
Authors: Paulsrud Bjarne 
Published: May 2018

Most sludges from small wastewater treatment plants in Norway are either dumped in sanitary landfills or utilized on agricultural land. Norwegian guidelines for wastewater sludge disposal recommend all sludges to be dewatered prior to disposal. For agricultural use the sludge should be stabilized at the treatment plant or stored in piles for at least six months before utilization.
Almost every plant has possibilities for sludge gravity thickening, and polymer addition is becoming quite popular for that process. Dewatering of sludge will often take place at a larger treatment plant, or In areas with no such plants, dewatering lagoons and mobile dewatering trucks are employed. For sludge stabilization, aerobic digestion is the predominant method.
Steps in Planning the Expansion of the Large Sewage Treatment Plant at Buchenhofen, Operated by the Wupper Watershed Management Association
Authors: Londong Jörg , Zander Stefan 
Published: May 2018

Sewage from 700,000 PE, roughly half of which is discharged by industry, is treated at the Buchenhofen plant operated by the WWMA, using a conventional, activated-sludge process without specific nutrient elimination.
A draft management plan has been prepared for the receiving stream of the treatment plant, the Lower Wupper. The chief forms of use for the waters are fixed in binding agreements. The use entailing the strictest limiting values is recreational fishing, which demands surface water quality class II.
Very substantial demands, which must be regarded as at least equivalent to state-of-the-art technology, are imposed on the Buchenhofen facility.
The Institut für Siedlungswasserbau, Wassergütewirtschaft und Abfalltechnik at the University of Stuttgart was commissioned to formulate realistic purification objectives for the treatment plant and to prepare expansion concepts.
At Buchenhofen, the single-stage activated sludge process with nitrification and preliminary de-nitrification has proved to be the most effective method for eliminating nitrogen while simultaneous precipitation followed by flocculation-filtration is the best process for eliminating phosphorus.
For purely scientific reasons, however, the extreme demands in terms of ammonium and nitrite rule out expansion of a treatment plant of this size. The proposed designs therefore require validation through commercial-scale testing.
Only after a 6- to 12-month test series has been evaluated will a draft design be prepared for approval, ultimately enabling the plant to be expanded and to fulfil the management planning objective of achieving surface water quality class II in the Wupper.
Comparison of Pollutant Load Calculation Methods Based on Measured Data – State of the Investigation
Authors: Russ H.-J. , Uhl M. 
Published: May 2018

The State Agency for Water and Waste in North Rhine-Westfalia, in co-operation with the Institute for Hydraulic Engineering of the Technical University of Darmstadt and the Institute for Water Management of the University of Hannover, is carrying out an investigation to compare and evaluate different methods for the calculation of pollutant loads. The investigation consists of two parts:Measurement projects in the variously configured combined sewer systems of two partial catchment areas. The aim of this is to obtain measured data to form the basis for the comparison of the calculation methods. It is also expected that advanced knowledge about the measurement techniques will be obtained.The comparison of the pollutant load calculation methods, with and without calibration, for both the catchment areas. Fifteen different methods for the computation of pollutant load are being compared. The comparison process is subdivided into five phases.
The measurement projects have been running successfully since 1987. The data base for the calibration of the models is available for one partial catchment. The comparison of models without calibration has already been completed.
An Evaluation of the Impacts of Discharges from Surface Water Sewer Outfalls
Authors: Payne J. A. , Hedges P. D. 
Published: May 2018

A broad-based approach has been used to assess the impacts of discharges to rivers from 47 surface water severs, with the objective of determining whether such discharges are damaging to stream quality.
In order to study as many sites as possible, sampling, laboratory and data analysis techniques were designed to be as simple and rapid as possible. This broad approach was deliberately chosen to contrast with other UK studies in which a small number of sites have been investigated in detail.
Three parameters were studied, all of which could reflect the effects of intermittent pollution on stream quality during dry weather. These were the numbers and types of benthic nacroinvertebrates upstream and downstream of the outfalls, the concentrations of metals in algae upstream and downstream of the outfalls, and the concentrations of metals in sediments upstream and downstream of the outfalls.
Information relating to the study catchments has been collected from local authorities and by observation at the time of sampling. This information includes catchment areas, land uses and receiving stream quality.
Methods used for site selection, sampling, analysis and data interpretation are described. Results show that there is a small but significant fall in biological water quality downstreap of outfalls, but no consistent detectable impact on the concentrations of metals in sediments or algae.
The biological effects are compared with the catchment characteristics to identify the factors governing the impact, and upstream water quality is found to be an important factor. Other factors influencing the impact are sewered catchment area and land use.
Dissolved Oxygen Stream Model for Combined Sewer Overflows
Authors: Schaarup-Jensen K. , Hvitved-Jacobsen T. 
Published: May 2018

Dissolved oxygen (DO) depletion in receiving streams during combined sewer overflows (CSO) is aphenomenon which comprises dry weather processes, including photosynthesis, and wet weather impacts. During a CSO event a distinction between immediate and delayed DO consumption in the stream caused by biodegradation of soluble and particulate organics, respectively, is made.
Two DO models have been developed in order to simulate the combined dry weather and wet weather effects. The first one is a simplified model based on the concept of an extended Streeter-Phelps equation and the second one is an advanced model, which is made from two integrated parts a hydro dynamic and a transport-dispersion model. The structure of the two models is described and model results are compared and evaluated.
A Study of Trash and Trash Interception Devices
Authors: Carleton M. G. , Nielsen J. S. 
Published: May 2018

The composition of trash found in urban stormwater runoff was analysed following its collection by a trash rack and two floating booms in Sydney, Australia. Basically garden refuse, plastic and paper products were the main components of the trash collected. The effectiveness of trash interception devices was examined using results of field trials. For various flow velocities, widths of channel or river, storm-related loads and cleansing frequency the choice of trash racks or booms can be made.
Testing of a range of trash rack designs was performed in the laboratory with the principal aim of preventing rack blockages. Whilst both spacing between bars and the angle of inclination of the rack were related to self cleansing, ultimate blockage could not be prevented for the configuration tested. Either the racks should be designed to allow for overtopping when blocked or booms be used, despite their lesser efficiency.