bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
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.
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.
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.
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.
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.
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.
Experimental Plants for Very Small Communities: Choice and Design Criteria for Five Different Processes
Authors: Boutin C. , Liénard A. , Ramain J. L. , Beyeler L. 
Published: May 2018

Waste stabilization ponds and land treatment seepage, which are generally used for very small communities, are being used less frequently due to their specificity and their lack of suitability in certain cases (ground characteristics, available space, fragile receiving bodies, etc.)
This article gives the choice criteria for the proposed new series for 5 communities sized between 50 and 400 p.e. (person equivalents), together with a detailed description of the facilities:-septic tank + covered infiltration bed-horizontal settling-digestion tank + covered infiltration bed-settling-digestion tank (Imhof tank) + trickling filter + infiltration bed-pond + covered infiltration bed-reed bed filters
in addition to the design of the infiltration beds and discussion of the investment costs.
All the series had to achieve the following effluent quality levels:COD = 90 mg/l, BOD5 = 30 mg/l, TSS = 30 mg/l, N-NK = 40 mg/l
For the time being, the difficulties encountered are of a technical nature and concern the infiltration beds' feeder devices which do not produce a flat water jet that gives even spreading.
Recovery of Poliovirus Type 1 from Experimentally Contaminated Shellfish: Evaluation of Different Methods
Authors: Croci L. , De Medici D. , Divizia M. , Gabrieli R. , Toti L. , Pana A. 
Published: May 2018

Outbreaks of viral gastroenteritis caused by ingestion of contaminated shellfish are well documented. Several methods have been described for virus recovery from shellfish, but often they are complicated and time-consuming.
In this study we have compared several viral extraction-concentration methods from mussels experimentally contaminated in conditions close to those met in natural environment.
Mvtilus galloprovincialis were contaminated by 2 h immersion in artificial seawater seeded with Poliovirus type 1. After the contamination step, the mussel bodies with intervalve water were homogenized by Ultraturax blender using four different elution buffers: PBS pH9.5; 0.05M glycine pH9.5; 0.3% and 3% beef extract pH9.5. The ratio between eluants and homogenates, depending on the used method, was 1:2 or 1:10.
After the elution step, virus was concentrated comparing the following techniques: precipitation at acid pH, precipitation with PEG6000, ultracentrifugation, ultrafiltration with Amicon apparatus and tangential flow Minitan system.
Statistical analysis was performed using ANOVA program and the results were evaluated.
Water Quality Impacts at Abandoned Hardrock Mines
Authors: Drabkowski Edwin F. 
Published: May 2018

Water quality pollution from abandoned mines is becoming an issue of growing awareness and concern. This concern is exacerbated by the fact that there are countless numbers of inoperative facilities with serious environmental, safety, and health problems. Abandoned tailings piles eroding heavy metals and sediment into watercourses, flooded tunnels and open pits filled with toxic water, unmarked open shafts and adits, and rotting timbers are some of the hazards facing unsuspecting humans and wildlife.
The purpose of this paper is to identify and characterize water quality sources at abandoned hardrock mine sites and best management practices (BMPs) used to control polluted runoff. There is a need to clearly define the best approach for controlling nonpoint pollution sources at abandoned mines. These are issues that could be addressed in reauthorization of the Clean Water Act.
Reducing Agricultural Sediment: An Economic Analysis of Filter Strips versus Micro-Targeting
Authors: Pritchard T. W. , Lee J. G. , Engel B. A. 
Published: May 2018

This study compares the physical and economic cost effectiveness of vegetative filter strips in reducing sediment loadings in a small Indiana watershed versus micro-targeting. The cost efficiency of each program is compared. Sediment loadings are estimated for a typical midwestern watershed area using ANSWERS, an event based distributed parameter model.
The results of this analysis indicate that a filter strip program in the Finley Creek watershed reduced sediment yields by 27 percent. An equivalent micro-targeted program taking 11 percent of the most erosive cropland elements out of production would reduce sediment yields by 31 percent. The information intensive micro-targeting program reduces sediment yields by amounts only slightly higher than a filter strip program. Using a land rental rate of $85 per acre, the filter strip program costs $91 per ton of sediment abated and the micro-targeting program costs $78 per ton of sediment abated, a 17 percent difference in cost. Since identifying ephemeral and perennial channels is much easier than identifying upland acres contributing the most sediment, a filter strip program will likely have lower administrative and enforcement costs. Thus a filter strip program, which reduces sediment yields nearly as much as the micro-targeting program, may be more cost effective when considering administrative and enforcement costs of each program.
Using Gleams to Evaluate the Agricultural Waste Application Rule-Based Decision Support (AWARDS) Computer Program
Authors: Ford D. A. , Kruzic A. P. , Doneker R. L. 
Published: May 2018

AWARDS is a rule-based program that uses artificial intelligence techniques. It predicts the potential for fields receiving agricultural waste applications to degrade water quality. Input data required by AWARDS include the physical features, management practices, and crop nutrient needs for all fields scheduled to receive these nutrients. Based on a series of rules AWARDS analyzes the data and categorizes each field as acceptable or unacceptable for agricultural waste applications. The acceptable fields are then ranked according to their potential for pollutant loading.
To evaluate the validity of the AWARDS field ranking system, it was compared to pollutant loading output from GLEAMS, a complex computer model. GLEAMS simulated the characteristics of each field ranked by AWARDS. Comparison of the AWARDS field ranking to the GLEAMS pollutant loading was favorable where ground water and both surface and ground water were to be protected and less favorable where surface water was to be protected. The rule base in AWARDS may need to be refined to provide more reasonable results where surface water is the resource of concern.
Aspects of a Computational Model for Salinity Variations in a Well-Mixed Tidal Reach
Authors: Reddy G. S. , Ghosh S. N. 
Published: May 2018

This paper deals with the development of a computational model for predicting the salinity variation in a comparatively long and narrow well-mixed tidal reach. The model is hated on the coupled numerical solution of unsteady flow hydrodynamic equations of continuity, momentum and salinity transport using implicit finite difference scheme. The computational scheme selected is the classical double sweep algorithm, for solving a set of simultaneous linear algebraic equations. The scheme is unconditionally stable and can be used for non-uniform space and time steps. It has also a higher order of accuracy than the existing schemes.
The software developed has been run with the available water level data in the Hooghly River system with appropriate initial and boundary conditions (Reddy et al., 1992). It is then adopted for production runs to provide information with regard to the variations of tidal levels, discharges and salinities.
Biological P-Removal: State of the Art in The Netherlands
Authors: van Starkenburg W. , Rensink J. H. , Rijs G. B. J. 
Published: May 2018

In the Netherlands the effluent requirements of municipal waste water treatment plants for P will become stricter in 1995. Depending on the design capacity of the waste water treatment plant the effluent requirement will be 1 mg/l P for plants with a treatment capacity of over 100,000 p.e. and 2 mg/l for a lower capacity.
From all the P-removal techniques, such as chemical precipitation, fluid-bed pellet reactor and magnetic separation, the most promising technique in the Netherlands would seem to be biological P-removal with or without a combination of the three other techniques.
In this paper a description is given of biological P-removal, especially the principle, the factors affecting biological P-removal performance, the different modifications and an example of each system in the Netherlands.