bluuebunny/crossref_metadata_2025 huggingface dataset:
A Nitrogen Balance for Austria
Authors: Fleckseder H.
Published: May 2018

The mass flux approach is a good tool to tell whether decisions in pollution control to be taken or already taken are adequate. In policy making, the boundaries for the mass flux approach can be either national borders or catchment areas of river basins. In the following, a nitrogen balance is presented for Austria for the year 1986, including the reason to undertake the work and the type of approach taken. In addition, the nitrogen balance is discussed and some conclusions are drawn on actions required.
Point Source Phosphorus Management, a Five Year Southern African Experience
Authors: Steynberg M. C. , Viljoen F. C.
Published: May 2018

The Vaal River Barrage reservoir is an important source of raw water for the Rand Water Board. Activities in the catchment of this reservoir resulted in enrichment of this water with concomitant eutrophication related water quality problems being experienced by the Rand Water Board.

In order to limit enrichment of raw water a standard of 1 mg PO4−P/ℓ for waste water treatment plant effluent was imposed and the effects of this standard on the algal concentrations at the No. 1 intake in the Vaal River Barrage reservoir was investigated.

Although only 24 per cent of waste water treatment plants in the catchment of the Vaal River Barrage reservoir complied with the phosphate standard for more than 75 per cent of the time, the amount of phosphate emanating from the treatment plants in general decreased significantly. This resulted in a lower orthophosphate concentration at the Board's No. 1 intake. The associated lower chlorophyll concentrations at No. 1 intake was, however, not only due to the lower orthophosphate concentrations, but also to the residence time and chemical/physical factors.

To limit the algal concentrations at No. 1 intake, the 1 mg/ℓ orthophosphate standard will have to be enforced strictly and diffuse source management will have to be implemented.
Stormwater Treatment in Combined Sewer Systems in Germany
Authors: Pecher R.
Published: May 2018

The use of stormwater detention tanks and their effect on combined sewer system are discussed. The design process is outlined, with particular attention to the most recent ATV guidelines.
Modelling of Solute Transfer to Surface Runoff
Authors: Lai J. L. , Lo K. S. L.
Published: May 2018

A mixing-based model for describing solute transfer to overland flow was developed. This model included a time-dependent mixing depth of the top layer and a complete-mixed surface runoff zone. In a series of laboratory experiments, runoff was passed at various velocities and depths over a medium bed. The media were saturated with uniform concentration of potassium chloride solution. Runoff water was sampled at the beginning and end of the flume and the potassium chloride concentration analyzed. Using this model, dimensionless ultimate mixing depth and dimensionless change rate of mixing depth from experimental data were investigated and implemented. The results showed that the Reynolds number and relative roughness are two important factors.
Management of Dutch Estuaries the Ems-Dollard and the Western Scheldt
Authors: Hoogweg P. H. A. , Colijn F.
Published: May 2018

In this paper the ecological situation of two Dutch estuaries will be described in relation to efforts of the Government to maintain or restore their environmental quality. The two estuaries are the Ems-Dollard estuary and the Western Scheldt. Both form the border with Germany and Belgium respectively and therefore are a potential management problem with respect to pollution crossing the borders between the countries involved. Therefore international consultation is needed to tackle environmental problems. Both estuaries are the remaining real estuaries of the Netherlands which can be conceived as one large Delta region of the rivers Rhine, Meuse, Scheldt and Ems. Plans for the sanitation of all rivers have been proposed and are in development as e.g. the Rhine Action Plan. For the smaller rivers like the Ems and Scheldt agreements about the reduction of pollutants have been made within the framework of the North Sea ministerial conferences. The ecological values of these estuaries are diminished through pollution, resulting in a reduced biological diversity, or reduced numbers of species. At present measures are taken to improve the ecological value which is based on the former ecological situation (ten Brink et al., 1991). Besides pollution also dredging and dumping of dredged material has levelled down the biological diversity and numbers of plants and animals.
Economic Issues in Water Privatisation and Regulation
Authors: Glynn D. R. , Baker W. R. , Jones C. A. , Liesner J. L.
Published: May 2018

During the privatisation of the United Kingdom water and sewerage industry a wide range of important and challenging practical economic issues were encountered, many of which also arise in some form or other throughout the developed and developing worlds. One such issue is the control of the prices charged for public water supply and sewerage, sewage treatment and disposal services. This paper explores some of those issues, analyses how privatisation and regulation have been shaped in order to address them, and, where possible, evaluates performance so far. Where appropriate, examples of how similar issues have been tackled are given for other countries, including the US and France.
The International Drinking Water Supply and Sanitation Decade: Dogmatic Means to a Debatable End
Authors: O'Rourke E.
Published: May 2018

The International Drinking Water Supply and Sanitation Decade (1981-1990), has called for a whole new approach to water sector development. The spotlight is on communities - community participation, community management, community financing - and away from national and local government structures. In this paper it is argued that the Decade rhetoric has not created the capacity and infrastructural networks to achieve and sustain its objective of universal water and sanitation coverage. The result is a contradiction between strategy and structures. It is concluded that community participation and community management may be conducive to achieving the Decades target; but are not sustainable alternatives to strong local and national government institutions in the water sector.
Use of Aquatic Macrocosms for Determining Site-Specific Water Quality Criteria
Authors: Isom B. G.
Published: May 2018

Use of aquatic macrocosms for determining site-specific water quality criteria for hardness dependent metals (copper, lead) and total dissolved solids (salinity) is discussed. Inadequacies of generic criteria for application to site-specific needs was indicated. Generic criteria for metals were based on laboratory data alone. Site-specific water quality effects such as naturally occurring total organic carbon were not considered by USEPA when developing critera. It is often advantageous to develop site-specific criteria for an effluent due to local conditions that protect the environment. The case studies were conducted on an acidic stream with high organic carbon content associated with natural humic materials.
Kinetics of Biofilm Detachment
Authors: Peyton B. M. , Characklis W. G.
Published: May 2018

In predictive biofilm modeling, the detachment rate coefficient may be the most sensitive variable affecting both the predicted rate and the extent of biofilm accumulation. At steady state the detachment rate must be equal to the net growth rate in the biofilm. In systems where organic carbon is growth-limiting, the substrate carbon utilization rate determines the net biomass production rate and, therefore, the steady state biomass detachment rate. Detachment rates, first order with biofilm thickness, fit the experimental data well, but are not predictive since the coefficients must be determined experimentally.
Formation of Biofilms on Small Suspended Particles in Airlift Reactors
Authors: Tijhuis L. , van der Pluym L. P. M. , van Loosdrecht M. C. M. , Heijnen J. J.
Published: May 2018

To overcome the current problems of waste water treatment systems new technologies have to be developed. A promising system is the Biofilm Airlift Suspension-reactor. The aim of these experiments was to determine the effect of dilution rate and acetate loading rate on the early stages of biofilm development in BAS-reactors.

During biofilm development bacteria colonize the carrier surface at specific sites in the form of microcolonies which gradually grow out to a full biofilm. Biofilm formation only occurs if the dilution rate is greater than the maximum specific growth rate of the micro-organisms. The yield of biomass on substrate might decrease with decreasing growth rate. More than 95% of the biomass production in the biofilm is transferred by detachment processes to the liquid phase and washed out of the reactor. To elucidate the mechanisms of this detachment processes more experiments are needed.
Ferrate vs Traditional Coagulants in the Treatment of Combined Industrial Wastes
Authors: de Luca S. J. , Cantelli M. , de Luca M. A.
Published: May 2018

This study assesses the use of potassium ferrate in the joint treatment of combined domestic and industrial wastewaters. The main feature of this compound is its simultaneous oxidant-coagulant properties. A pilot plant for physicochemical treatment was utilized for tests with combined effluent. The removal of pollutants achieved at the pilot plant fulfills the standards of emission for liquid industrial effluents, established by regulatory agencies.

A comparison was also made of the efficiency of pollutant removal between potassium ferrate, ferric chloride and aluminium sulphate for the above-mentioned combined wastewater. All coagulants are very effective in this physicochemical treatment, with an advantage for disinfection, smaller dose and sludge generation to ferrate treatment.
The Purification Efficiency of Planted Soil Filters for Wastewater Treatment
Authors: Netter R.
Published: May 2018

The poster describes investigations on two planted soil filters for wastewater treatment (constructed wetlands with subsurface water flow), which are filled with various kinds of soil. The filters are planted with helophytes. The hydraulic surface loading was between 4 and 60 mm/day. The purification efficiency was between 72 and 99 % with respect to BOD5 and between 61 and 99 % with respect to COD. The elimination of the nutrients (Ntot and Ptot) varied between 5 and almost 100 %.
Bioaccumulation of Polychlorinated Biphenyls and Organochlorine Pesticides in Selected Fish Species as an Indicator of the Pollution of Aquatic Resources in Vojvodina, Yugoslavia
Authors: Vojinovic-Miloradov M. , Marjanovic P. , Buzarov D. , Pavkov S. , Dimitrijevic Lj. , Miloradov M.
Published: May 2018

Long term pollution of selected aquatic resources of Vojvodina with polychlorinated biphenyls (PCB's) and organochlorine pesticides (OCP's) has led to high degree of bioaccumulation of the above chemicals along the food chain. This paper documents the bioaccumulation in two fish species commonly found in rivers and canals of Vojvodina, common carp (Cyprinus Carpio) and pike (Exos lucinus). Samples offish, sediment and water were collected from the Danube, Sava and Tisa rivers and a fish farm “Ečka” which is supplied with water from the river Tisa and river Begej.

All samples were analysed by highly sensitive capillary column GC using EC detectors. Samples were analysedfor aspectrum of compounds and are presented here as total PCB's and OCP's.

The results show that the studied compounds are present in water samples at very low concentrations (PCB's in concentrations at or below the limit of detection, OCP's in concentrations below the legally allowable concentrations by Yugoslav norms). The sediment samples contain the studied compounds at significantly higher concentrations but still within the expectable range. Fish tissue contained elevated concentrations, and especially so the tissue of the top predator in the food chain, the Pike, showing that bioaccumulation has occurred. Of special concern are the extremely high concentrations of PCB's in the tissue of fish samples collected from river Sava indicating the still existing effects of pollution by PCB's in the watershed of the river Sava.
Verification of Dispersion Model on Anaerobic Reaction Simulation
Authors: Tseng S.-K. , Lin R.-T. , Liau K.-L.
Published: May 2018

A dispersion model was established on the combination of biological reaction and related physical-operational characteristics, such as dispersion, diffusion, cell accumulation and transportation. Also, the feasibility of the dispersion model in anaerobic filter digester simulation was identified. Under low loading rate and without recirculation, the digester behaves like a plug flow reactor. Therefore, the simulated results of dispersion model and plug flow model are similiar. However, at higher loading rate, the dispersion of digester increases, and the simulated results of the dispersion model are closer to experimental data than the plug model. That proved the applicability of dispersion model in anaerobic reaction simulation.
Solubilization of Particulate Cellulose Using Anaerobic Acidogenesis
Authors: Chyi Y. T. , Levine A. D.
Published: May 2018

Hydrolysis and acidogenesis in anaerobic digestion comprises the first step in converting biodegradable particulates into methane gas. The optimum conditions in this stage are different from those for methanogenesis. Results of tests to solubilize organic particulates of a known size distribution are presented and discussed here.
Practice of Quasi-Optimum Controlling Urban Sewage Conveyance System of Moscow
Authors: Ermolin Yu. A. , Zagorsky V. A.
Published: May 2018

The optimum controlling the process of sewage conveyance in the system of wastewater disposal of Moscow is considered. The mathematical model of object as algebraic correlations described in matrix form is made up. Determination of optimum redistribution of the sewage flows is restricted by the capacity of structures. The criterium of the control is the minimum of the wastewater cost. The calculation of the optimum redistribution of the flows on conveyance mains is reduced to the problem of linear programming. The results of verification of the proposed algorithm of the control in production conditions are given. After 40 days of experimental regime the decrease of the energy consumption for conveyance of a unit of the sewage volume to 4.2% has been stated. Saving of more than 700000 kW/h of the energy was achieved, which had been fixed by the pumping station counters. A conclusion has been made about technical possibility and economic efficiency of the complete automation of the process of wastewater disposal in a ramified urban communal sewer network.
Cells on Rotating Fibers for Wastewater Treatment
Authors: Clyde R.
Published: May 2018

Fibers have a high surface area so many cells can be immobilized and when the fibers are rotated, fast reactions occur. When Celite® is entrapped in the fibers, even more area is provided. Half a pound of Celite® has the area of a football field! Toxic metals can be removed from wastewater. Pulp mill effluent can be cleaned. Phenol is degraded and the sulfur taken out of coal. A non-polluting road deicer is produced which doesn't corrode bridges or cars and ethanol for cars puts less lead into the air and water. When an RBC (rotating biological contactor) is run half full and a light shone in the top, the light hits a thin moving film to degrade dioxin.
Training Treatment Plant Operators Using the “Optrain” Computer Simulator
Authors: Schreiber R. P. , Paulsen M. J. , Schafer D. E.
Published: May 2018

Training wastewater treatment facility operators is a crucial function because of their responsibility for keeping treatment plants operational and running efficiently. On-the-job training carries the risk of upsetting plant operations and jeopardizing effluent quality, because operators being trained will make mistakes during the learning process. One training method that can reduce this risk is to train new operators on a computer simulator. OPTRAIN, developed for the State of Massachusetts, and now in use at other locations, is one such tool that has been used successfully in training sessions that bridge the gap between textbook teaching methods and apprenticeship learning. The purpose of this presentation is to describe the simulator and to show how it has helped train operators successfully.
The Way to Control Water Pollution of the Huaihe River
Authors: Liu Y. , Zhu W.-H.
Published: May 2018

The Huaihe River has been polluted to the most serious extent among the six largest rivers in China. Water pollution of the river characterizes organic pollution. This paper, giving Bengbu Section of the river as an example, discusses the way to control water pollution of the river. Some realistic measures can be adopted in line with local conditions in order to resolve the water pollution problem of the river step by step.
TLC Determination of Aquatic Humic Acids
Authors: Kaštelan-Macan M. , Cerjan-Stefanovic Š. , Jalšovec D.
Published: May 2018

Humic acids are mostly determined by spectroscopic methods, although they are not accurate enough, because humic acids possess no maximum absorption at any wavelength in the ultraviolet and visible spectrum. In this contribution the accurate and precise method for aquatic humic acids determination, using thin layer chromatography, was worked out. Previously, humic acids were separated and preconcentrated -from the river water, using macroreticular adsorption resin Amberlite XAD-4, and subsequently determined by TLC. The Chromatographie system was: silicagel HF254(Merck, precoated plates 20 × 20 cm) and NH3 -acetone (60:40,v/v) as a solvent system. Quantitative determination was made by Camag– Turner 111 Fluorimeter, by measuring UV–quenching.
Partitioning of a Surfactant Between Lake Water, Suspended Solids and Sediment
Authors: Amano K. , Fukushima T.
Published: May 2018

The partitioning of linear alkylbenzenesulfonates (LAS) between solution and adsorbed phases and the factors of the partitioning are summarized herein based on the field observation and the adsorption experiment. All adsorption experiments using suspended solids and sediment solids taken from Lake Teganuma were performed between 0.2 and 6 mg l−1 of the initial LAS concentrations. The relationships between the partition coefficient of LAS and two factors of solid concentration in the water and the fractional organic carbon content of solid were confirmed. Based on our experimental results, it was expected that the partition coefficient of LAS in the natural water or sediment could be estimated by an empirical model, and this model was verified by using the adsorption data from field observations. A reasonable agreement between the observed and the predicted partition coefficient was obtained (correlation coefficient was between 0.48 and 0.83).
Characteristics of Colloids in Landfill Leachate
Authors: Gounaris V. , Anderson P. R. , Holsen T. M.
Published: May 2018

Colloidal material in landfill leachate were separated and fractionated in size fractions. Analyses were performed to obtain the mass, elemental composition, and pollutants associated with the colloids in each fractions. The stabilization mechanism of the colloids is studied to evaluate their mobility potential.
The Advantages of a Compact Filter for Individual or Semi-Collective Waste Water Treatment
Authors: Fazio A. , Warot G. , Vander Borght P.
Published: May 2018

In certain rural areas, collective water treatment is not an economically viable solution due to the cost of the water collection facilities (difficult terrain, distance between the houses); for various reasons, however, the traditional individual water treatment system is not highly regarded (bad installation, insufficient maintenance, …) and thus, work has been carried out to develop a high-performance and compact alternative solution for domestic waste water treatment.

This alternative system makes use of a compact sand filter installed downstream from the septic tank, the filter's performance is based on supply regulation and improvement of the waste's surface distribution.

Hydraulic laboratory studies and follow-up on a testing stand using real effluent have enabled us to develop a standardized compact system which is suitable for use in most terrains. The filter's purification performance is outstanding; at a daily supply rate of 150 l/m2, the average purification yields are over 90 % for COD, BOD, NH4, NKT

From the bacteriological point of view, bacterial contamination is also significantly reduced.

Laboratory tests are being carried out at present, with the aim of further improving purification by inducing a denitrification process enabling reduction of nitrate levels.

This system's compact overall dimensions and relatively low cost mean that it can be used not only for individual waste water treatment but also for effluent treatment for small communities (≤ 400 inhabitant equivalent).
Anaerobic Storage of Activated Sludge: Effects on Conditioning and Dewatering Performance
Authors: Bruus Jacob H. , Christensen Jimmy R. , Rasmussen Hanne
Published: May 2018

Since dewatering equipment is commonly operated only during normal working hours, activated sludge must often be stored in an anaerobic condition prior to conditioning. It is the objective of this study to investigate the influence of anaerobic storage on conditioning requirements and dewatering performance on a laboratory scale. Sludges were collected at two large treatment plants (removal of organic matter, nitrogen and phosphorus) and one small treatment plant (removal of organic matter). Thickened activated sludges from the three wastewater treatment plants were stored anaerobically in the laboratory and analyzed frequently during fourteen days of storage. Both organic and inorganic conditioning was used.

Turbidity and Dissolved Organic Carbon (DOC) in the sludge bulk water increased as a result of the anaerobic storage. These parameters indicated a release of colloids, dissolved exopolymers and fermentation waste products such as fatty acids to the bulk water. These constituents consumed additional cationic polyelectrolyte. Filterability at the optimal dosage of polyelectrolyte was not affected by anaerobic storage. Therefore, polyelectrolyte requirements are governed by the bulk water constituents, whereas filterability of the sludge is determined by the degree of sludge floc conditioning. Iron requirements seemed unaffected by anaerobic storage, but lime requirements to obtain good filterability increased with anaerobic storage time.
Research on Organic Acid Fermentation of High Molecular Organics with Short Hydraulic Retention Time
Authors: Somiya I. , Ono Y. , Uesaka T.
Published: May 2018

An experimental work has been performed to make clear the effect of high molecular substrate on organic acid fermentation reaction with short hydraulic retention time by using three kinds of substrate and a reactor under both conditions in fill & draw type and batch type, and introducing an aliquot of previously incubated sludge. As substrate which has to be hydrolyzed before the intake into cell, cellulose(CMC-Na), starch and peptone have been selected. Peptone was used as a basic control substrate in every test to supply organic nitrogen and other fundamental materials. The hydraulic retention time was set from 16 hours to 48 hours. Within these HRT's the organic acid forming bacteria could grow at the order of 109 cells/mL. The introduced substrate could be converted into organic acid in the level of 30 to 40% on TOC. It became clear that the decomposition of cellulose into organic acid is rather difficult and its rate is less by around one fourth than that of starch. By applying sequential first order reactions to illustrate the fermentation reactions, a mathematical model has been developed and applied to evaluate the reactionconstants of the fermentation process by parameter fitting methods. The rate constants on hydrolysis of cellulose and starch were calculated to be 0.042 hr−1 and 0.255 hr−1, respectively.
Quicklime Pre-Conditioning of Sludge to be Dewatered in Centifuges Lowers Disposal Costs
Authors: Denkert R. , Retter E. A.
Published: May 2018

The pre-conditioning of digested municipal sewage sludge with quicklime prior to dewatering was investigated as an alternative to conditioning the dewatered sludge with quicklime. Powdered lime was added to the sludge in a stirred tank reactor before dewatering in a solid-bowl centrifuge. The preconditioning was found to positively influence the dewatering performance of the centrifuge, resulting in significantly lower specific polymer and lime consumption and a reduced total quantity of dewatered cake for disposal. Total costs for operating chemicals and for transport and landfill of the sludge were determined to be approximately 15 % lower for pre-liming than for the post-liming process.
High Pressure Treatment of Organic Wastes
Authors: Döllerer J. , Wilderer P. A.
Published: May 2018

High pressure treatment of organic materials was introduced several years ago by Japanese researchers as a means to preserve food. Application potentials are also envisaged in the field of waste treatment. Hygienization effects, for instance, are achieved, when microbially contaminated samples are placed into an isostatic press and exposed, at room temperature, to a pressure of 4,000 bars and above. Deformation of the biopolymers under those extreme pressure conditions leads to effects such as coagulation, denaturation of proteins, crystallisation and/or gelatinization (Heremans 1992). As a result the microorganisms lose viability within a few minutes.
Calcium Silicates as Lime Substitute
Authors: Pìnarlì V. , Saul G. M.
Published: May 2018

An experimental study has been carried out of the removal of iron from solutions of ferric chloride by lime, β-dicalcium silicate (C2S) and α-monocalcium silicate (CS) and of the treatment of the resulting sludge. C2S promoted the flocculation of iron precipitates to achieve higher settling, thickening and dewatering rates. The effect of first minute settling time is especially evident that 60% and 22% of the iron respectively was removed when 0.39 g/l of C2S and 0.21 g/l of lime were applied to solutions containing 100 mg/l Fe3+. 99% and 48% of the iron respectively was removed in the first two minutes of settling period when 3.90 g/l of C2S and 2.10 g/l of lime were applied to solutions containing 1000 mg/l Fe3+. Zone settling and thickening of the iron flocs below a sludge blanket formed were observed and zone settling velocities were determined as 4.6 and 3.7 cm/minute for C2S and lime, respectively. When C2S was used as precipitant for different iron concentrations i.e. 10, 100, 1000 mg/l Fe3+, the sludges produced bad lower specific resistance to filtration (5.38×1012, 1.75×1012, 1.13×1012m/kg) than that(6.77×1012, 5.76×1012, 3.98×1012m/kg) when lime was used, respectively. C2S treatment significantly increased the filter yield hence reduced the size of the dewatering plant.
Influence of Enhanced Biological Phosphorus Removal on Sludge Treatment
Authors: Johannes Pöpel Hermann , Jardin Norbert
Published: May 2018

During sludge treatment at plants with biological phosphorus elimination, part of the stored phosphate can be released into the liquid phase of the process water and recycled back with the return water to the wastewater treatment part, resulting in an increase of the phosphorus load. From a theoretical examination it can be derived that the phosphate feedback from sludge thickening processes is lower than 5 %. A nearly complete phosphate release can be expected during sludge stabilization. Dependent on the wastewater conditions, a chemical fixation of the released phosphate in form of calcium-phosphate-precipitates or ammonium-magnesium-phosphate is possible. Therefore, the concentration of soluble phosphate in the supernatant of digester water at large biological phosphorus removal plants is often very low. The paper also describes techniques to prevent a phosphate feedback. Emphasis is placed on the chemical conditioning of the stabilized sludge or precipitation of the process water from sludge treatment.
Adsorption Characteristics of a Biotreated Pulp Mill Effluent
Authors: Çeçen Ferhan.
Published: May 2018

Spent bleaching effluents from the chlorination and extraction steps of a sulfate pulp mill were subjected to activated carbon treatment to investigate the elimination of nonbiodegradable matter. For this purpose the biotreated waste water containing mainly nonbiodegradable matter was treated with different activated carbon types. The elimination degree of nonbiodegradable matter was determined and adsorption isotherms were generated in terms of the parameters COD, DOC, Color436 and UV254. The removal level was over 90% when the carbon dosage exceeded 10 000 mg/l. AOX compounds could be eliminated over 90%. The isotherms could be expressed by the Freundlich equation. It was shown that the shape of the isotherms was strongly dependent on the carbon dosage employed. According to carbon dosage three different adsorption regions were distinguished and for each region the corresponding Freundlich constants K and n were determined. Carbon addition led to a change in the composition of wastewater as shown by decreasing COD/DOC, UV254/DOC and Color436/DOC ratios. Further it was shown that the relatively fast color and UV analyses were accurate enough to characterize the adsorptivity.
Mathematical Modelling of Anaerobic Mesophilic Sewage Sludge Treatment
Authors: Siegrist H. , Renggli D. , Gujer W.
Published: May 2018

A mathematical model was developed to describe the dynamic behaviour of the anaerobic mesophilic digestion. Special emphasis was given to the acetate degradation kinetics, as the step that determines the stability of anaerobic digestion. From the safety factor (maximum/average degradation rate) of acetate degradation in the range of 5.3 to 23 days hydraulic detention time, a maximum observed growth rate of 0.37 d−1 and decay rate of 0.10 d−1 were estimated. Temperature and pH dependence of acetate conversion was also determined and included in the model. The model was verified with load variation experiments on laboratory and full scale digesters. Mesophilic digestion with anaerobic thermophilic pretreatment is more sensitive to load variation than single mesophilic digestion. However two stage treatment leads to better sludge characteristics (thickening, viscosity, COD, TSS) of the treated sludge.
Control of Two Step Anaerobic Degradation of Municipal Solid Waste (MSW) by Enzyme Addition
Authors: Lagerkvist A. , Chen H.
Published: May 2018

The addition of cellulolytic enzymes to MSW has been tried under methanogenic and acidogenic conditions in 0.1 m3 landfill models. An enhanced degradation seems to follow the enzyme addition in both cases. During acidogenic conditions the observed conversion of cellulose was 42 and 29 % respectively, with and without enzyme addition. The enzyme addition did not result in a change from methanogenic to acidogenic conditions. A similar conversion of VS can be achieved during methanogenic and acidogenic conditions; at the completion of this experiment the conversion of VS was in excess of 50 % in the methanogenic models and somewhat lower than 40 % in the acidogenic models (the latter still yielding strong leachates). The results of some standard waste-water analyses were compared and it is concluded that especially acid leachates may cause analytical problems.
The Kinetics of Glucose Decomposition with Sulfate Reduction in the Anaerobic Fluidized Bed Reactor
Authors: Matsui S. , Ikemoto Yamamoto R. , Tsuchiya Y. , Inanc B.
Published: May 2018

Using a fluidized bed reactor, experiments on glucose decomposition with and without sulfate reduction were conducted. Glucose in the reactor was mainly decomposed into lactate and ethanol. Lactate was mainly decomposed into propionate and acetate, while ethanol was decomposed into propionate, acetate, and hydrogen. Sulfate reduction was not involved in the decomposition of glucose, lactate, and ethanol, but was related to propionate and acetate decomposition. The stepwise reactions were modeled using either a Monod expression or first order reaction kinetics in respect to the reactions. The coefficients of the kinetic equations were determined experimentally. The modified Monod and first order reaction equations were effective at predicting concentrations of glucose, lactate, ethanol, propionate, acetate, and sulfate along the beight of the reactor. With sulfate reduction, propionate was decomposed into acetate, while without sulfate reduction, accumulation of propionate was observed in the reactor. Sulfate reduction accelerated propionate conversion into acetate by decreasing the hydrogen concentration.
Effect of Two-Stage Treatment on the Biological Treatability of Strong Industrial Wastes
Authors: Germirli F. , Orhon D. , Artan N. , Ubay E. , Görgün E.
Published: May 2018

Some agro-industries generate wastewaters with very high COD concentrations and require two-stage biological treatment Inert or residual organic constituents of these wastewaters, even at very low ratios, play a major role in the compliance of effluent standards. In this study, two strong wastes, citric acid plant effluent and cheese whey were tested for their inert COD content. The experiments showed that the first-phase anaerobic treatment provided a major decrease in the residual COD, but introduced significant amounts of particulate residual COD to the second phase. A newly developed procedure was used for the assessment of the soluble and particulate residual COD.
Anaerobic Co-Digestion of Sewage Sludge and Concentrated Soluble Wastewaters
Authors: Carrieri C. , Di Pinto A. C. , Rozzi A. , Santori M.
Published: May 2018

The anaerobic treatment of sewage sludges (primary and secondary) mixed to concentrated soluble wastes (olive mill effluents, cheese whey and landfill leacheate) in conventional once-through and anaerobic contact digesters, has been investigated in laboratory scale reactors. Experimental results indicate that it is possible to increase appreciably (100 %) the volumetric loading rate of sludge digesters (anaerobic contact) by addition of soluble substrates and keep stable operating conditions. The proposed treatment is economically very attractive if the load due to high strength wastewaters is of the same magnitude as the sludge load, as it does not require additional reactor volume.
Microbiological Processes in Landfills
Authors: Nozhevnikova A. N. , Nekrasova V. K. , Lebedev V. S. , Lifshits A. B.
Published: May 2018

Large landfills in the Soviet Union cover more than 140 thousand hectares. The gas emission intensities are extremely disproportional over the surface of these landfills. According to our data the rates of streams of the biogas components vary from 0 till 20, 46, 1.2 and 0.75 (×10−4m3 × hour −1/m2) for CH4, CO2, H2, CO, respectively. The stable carbon isotope composition of methane and carbon dioxide in the biogas of deep landfills layers is typical for methanogenesis from organic wastes, but it depends on the concentration of organic substance in the landfill ground and on the age of these landfills. In the upper layer methane becomes heavier and carbon dioxide lighter due to the microbiological oxidation processes. The most intensive methanogenesis is usually observed in the upper part of the anaerobic zone where the organic substance concentration is relatively high. The methanogenic microflora is represented by mesophilic methanobacteria, species of Methanosarcina and Methanobacterium genera are prevalent forms. At the depth of 10-100 cm from the surface intensive oxidation of methane, hydrogen and carbon monoxide is observed. The number of gas oxidizing bacteria is up to 10 cells per gram of soil. 14 species of methane oxidizing bacteria, which belong to 5 genera were iden tified. Hydrogen oxidizing bacteria belong to Alcaligenes,Pseudomonas, Paracoccus, Mycobacteriun genera. Between them psychrotrophic forms were found. It has been shown that in small landfills methane, produced in anaerobic zone, can be oxidized completely in the upper ground layer. The biogas extraction from landfills is important not only as an additional fuel source, but as a means of preventing pollution of the Earth's atmosphere.
Evaluation of Nutrient-Chlorophyll Relationships in the Rybinsk Reservoir
Authors: Mineeva N. M.
Published: May 2018

Our earlier study on the phytoplankton abundance and nutrient content in the Rybinsk Reservoir showed a weak correlation between chlorophyll a and nutrients. CHL:TP and CHL:TN ratios were used to quantitatively estimate the chlorophyll dependence on nitrogen and phosphorus. CHL:TP changed from 0.01 to 0.57 mg/mg in May-October 1981, 1982 and reached 1.46 in July 1989, CHL:TN ranged from 1-2 to 47 and to 56 mg/g, respectively. Variations of both indices through the ranges of CHL, TP, TN and TN:TP are given and their increment in eutrophic waters in comparison with mesotrophic ones is discussed. The present approach seems to be useful for the prediction and control of the eutrophication processes under the similar ecological conditions.
Comparative Studies on the Primary Treatment of Municipal Wastewater for Ocean Disposal
Authors: Chen Chiu-Yang
Published: May 2018

The objective of this study is to evaluate the effectiveness of primary treatment on municipal wastewater before it is discharged into the ocean. A series of filter papers of specified pore size was applied to measure the removal of organics and solids in wastewater through various primary treatment processes. For plain sedimentation, the removal of suspended solids was always less than 50% while COD and BOD removals were 23-41% and 15-27%, respectively. For chemical coagulation with the addition of poly aluminium chloride (PAC), 70% SS removal was obtained with a PAC dose of 30 mg/l. If polyelectrolyte is added (about 1 mg/l), the dosage of PAC can be reduced to around 10 mg/l to maintain the SS removal efficiency at the same level. For air flocculation treatment by preaeration followed by sedimentation, the most achievable removal of solids from wastewater of more than 80% was obtained at an aeration rate of 0.5-1.0 Nl air/l. In particular it is more effective for smaller solids than for larger solids in wastewater. On organic removal, about 15-40% removal in terms of COD or BOD was obtained by treating wastewater with either plain sedimentation or air flocculation and sedimentation processes. The efficiency of organic removal from wastewater increased to about 60% by utilizing chemical coagulation and sedimentation treatment. Based upon the characteristics of tested municipal wastewater, in order to maintain the SS removal at 65% or above as regulated, the treatment processes of chemical coagulation or air flocculation followed by sedimentation should be employed.
Activated Sludge Treatment of Phenoxy Herbicides and Chlorophenols
Authors: McAllister P. J. , Rao Bhamidimarri S. M. , Chong R. , Manderson G. J.
Published: May 2018

A laboratory scale activated sludge treatment system was developed for the treatment of phenoxy herbicide chemicals and the associated chlorophenols in a toxic landfill leachate. A novel sludge recycle system was employed to ensure high specific activity of the return sludge. The activated sludge treatment resulted in 99.5% removal of phenoxies and chlorophenols and 84% TOC reduction for 10% influent leachate concentrations. The corresponding toxicity reduction was 76%. An increase in influent concentration resulted in a decline in activated sludge performance.
Relationship between Oxygen Flux and Biofilm Performance
Authors: Huang Ju-Chang , Liu Yow-Chyun
Published: May 2018

A fundamental study was carried out to assess the relationship between the availability of dissolved oxygen in a laboratory-scale biofilm reactor with some important system performance parameters such as biofilm growth rate, organic stabilization rate, sulfide production potential, aerobic layer-thickness, film density, and biofilm sloughing patterns. The feed solution was filtered sewage supplemented with glucose to maintain an initial COD of 300 mg/l. Four DO levels were examined: 1, 3, 5 and 8 mg/l.

The test apparatus consisted of annular reactors, each having outer stationary and an inner rotating cylinders, so that the hydraulic shear throughout the reactor was uniform. The liquid space between the two concentric cylinders was 1.0 cm and the total growth surface was 1,200 cm2, while the liquid volume inside the reactor was 755 cm3. The rotating speed was controlled at 14 cm/s (0.46 ft/s) and the operating temperature was controlled at 20°C.

The results of this study have indicated that an increase of DO tends to increase the cell yield, the maximum active (or aerobic) layer thickness, as well as the COD stabilization rate. However, DO shows no apparent effect on the film's volumetric dry density. Instead, it is a function of the film thickness; i.e., the thicker film has a higher density. For a mature biofilm, the ratio of the aerobic to the total film thickness increases linearly from 0.08 to 0.27 when the DO is increased from 1 to 8 mg/l. The maximum COD removal rate at 8 mg/l DO and an initial COD of 300 mg/l is about 1.5 g/h/m2. Sulfide production starts to occur when the film thickness reaches 200 µm and the DO is at 1.0 mg/l. As the DO is increased to 8.0 mg/l, sulfide production still occurs when the film thickness reaches 700 µm. Therefore, odour production seems to be an inherent problem associated with the biofilm treatment system. The pattern of the biofilm sloughings seem to follow a 40- to 45-day cycle regardless of the operating DO. In most cases, massive and patchy sloughings occur for two to three days; beyond that, a gradual but steady redevelopment of the biofilm takes place. During times of sloughing, the overall treatment efficiency can be slightly affected, primarily due to the presence of high concentrations of SS in the treated effluent.
Dynamic Behaviour of Aerobic Submerged Biofilter
Authors: Hu Hong-Ying , Fujie Koichi. , Urano Kohei.
Published: May 2018

Dynamic behaviour of microbial film and BOD removal characteristics in an aerobic submerged biofilter packed with ceramic balls were investigated. The effects of BOD loading and temperature on the populations of bacteria and protozoa inhabiting microbial film were investigated. It was ascertained that the BOD removal rate by the microbial film was controlled by the bacterial population, while the microbial concentration in the biofilter was due to the growth of protozoa when the temperature and the BOD loading were low. The analysis of bacterial quinone mixtures was successfully applied to identify the bacterial population in the microbial film.
A New Perspective on Rural Water Supply and Sanitation
Authors: Mancy Khalil H.
Published: May 2018

It is claimed that the United Nations International Decade for Water Supply and Sanitation of the 1980s, has served to provide more than 1.3 billion people with capabilities tor adequate water supplies, and about 750 million with sanitation. The principle impact has been in rural communities of developing countries. Unfortunately, a considerable portion of these facilities are abandoned and inoperative. While completely manageable in the rich industrialized countries, water related diseases, e.g. infant mortality, child diarrhoea, and cholera epidemics persist in the poor countries of South America, Africa and Asia. The situation has been exacerbated by explosive population growth in the poor countries of the world.

Despite national and international commitment, water supply and sanitation services are not keeping up with the demand, and many investments have not been sustained. It is clear now that the major constraint, in the less developed countries, has not been the lack of funds or water supply and sanitation technology, but rather an absence of a capacity to develop, utilize and sustain the available resources.

Capacity building in a given country must come from within and it is basically a social-political process. The commitment of a country for capacity building of the water sector should be approached on two levels. On the national level this may entail changes in water related policies, establishment of legal, regulatory, and information systems, and the involvement of citizen groups and national professional organizations. On the local level, it is imperative to strengthen local institutional resources, technical, managerial and financial capabilities, and community involvement. Integration of water supply and sanitation agencies with local irrigation districts is frequently advantageous where water reclamation options are feasible. Examples from Egypt are presented.
Wastewater Reuse Potential in Turkey: Legal and Technical Aspects
Authors: Sarikaya Hasan Z. , Eroglu Veysel
Published: May 2018

Treated wastewater is one of the potential water resources in especially arid and semi arid regions. Overall, Turkey is not poor in terms of water sources. However, due to distribution of water in time and in space water shortage is felt. Wastewater reuse potential is especially high during summer months for agricultural and recreational purposes. In coastal areas of Turkey treated wastewaters from the coastal settlements are reused to irrigate the green areas and parks. Surplus effluents are discharged into the sea by use of marine outfall pipes. Extended aeration type of activated sludge processes followed by chlorination is the most common form of the treatment. Agricultural reuse is encouraged in inland rural regions. Simple wastewater treatment methods such as stabilization ponds are popular in rural areas. Water quality standards regulating irrigational wastewater reuse are recently set in Turkey. Guidelines given by World Health Organization (WHO) are generally adopted except the limits for the intestinal nematodes and the residual chlorine. Irrigational reuse standards as well as the degree of the treatment have to be revised based on the local experiences. Assurance of a given effluent quality is one of the major problems in management of the wastewater reuse in rural areas. Local examples are presented to illustrate this point.
Sludge Treatment and Disposal Systems for Rural Areas in Germany
Authors: Steinle Eberhard
Published: May 2018

First an overview of the systems currently in use and being discussed for sludge treatment is presented will) particular emphasis on distinguishing between the object of the system (conditioning objective of the various phases in the system) and a system concept (concept of various phases of the system in sequence to attain the disposal objective). More detailed information is given as to the salient systems as used with smaller sewage treatment plants in rural areas, such as digestion, dewatering, hygienization, composting and thermal drying.

A further item of discussion is how sludge treatment influences the sewage treatment process. For the critical emissions (nitrogen, phosphorus) demanded in Germany, and thus for the degree of sewage treatment required, the load of the sewage treatment system resulting from sludge treatment needs to be taken into account. Accordingly, operation of sludge treatment and sewage purification must always be harmonized. The extent of these return loads also limits the spatial centralization of the system phases; this applies in particular to smaller sewage treatment plants in rural areas.

In conclusion, an attempt is made to present a perspective for the agricultural utilization of such sludge in Germany. Since the critical values for emissions have been further tightened by new regulations, thus considerably elevating the associated sophistication of monitoring techniques, it is to be expected that the use of sewage sludge in agriculture will also be further reduced in rural areas, especially since public awareness of emission control has considerably reduced the acceptance of sewage sludge as fertilizer.