bluuebunny/crossref_metadata_2025_split huggingface dataset:
The implications of point source phosphorus management to potable water treatment
Authors: Heath Ralph G. , Steynberg Machiel C. , Guglielmi Rita , Maritz Annelie L. 
Published: May 2018

The Vaal River Barrage reservoir is an important source of raw water for Rand Water which supplies at least 10 million people with drinking water daily. Return effluents from waste water treatment works, industries and informal urban settlements in the catchment has resulted in algal problems in the raw water and treatment process.
In order to attempt to reduce the effect of eutrophication of South African inland water quality the Department of Water Affairs implemented in 1985 a 1 mg/l ortho-phosphate standard for waste water treatment works effluents.
The amount of phosphate originating from the waste treatment works decreased significantly over the 10 years after the standard was implemented even though 40% of the time the works do not comply to the standard. This has resulted in no significant change in the chlorophyll values at Rand Water Intake No. 1. The algal species composition has changed with blue-greens becoming more dominant which has resulted in a higher incidence of algal related problems. The stabilizing of the chlorophyll values is not only as a result of lower ortho-phosphate levels but also due to residence times, turbidity and conductivity.
To further reduce the algal concentrations at Rand Water Intake No. 1 the 1 mg/l ortho-phosphate standard will have to be enforced, the standard possibly reduced and diffuse sources managed on a catchment basis.
Oxygen transfer and aeration efficiency - influence of diffuser submergence, diffuser density, and blower type
Authors: Wagner Martin R. , Pöpel H. Johannes 
Published: May 2018

The main factors of fine bubble aeration systems in uniform arrangement in clean water are the air flow rate, the depth of submergence of the diffusers, and the diffuser density. While the influence of the air flow rate on the oxygen transfer parameters is known, knowledge of the influence of the depth of submergence and the diffuser density on the specific oxygen transfer efficiency SOTE [%/m] and on the specific oxygen absorption SOA [g/m3·m at STP] is very limited. Both parameters are of great importance in dimensioning fine bubble aeration systems. Therefore, a literature review was conducted to show the influence of the diffuser submergence and density and the type of blower on oxygen transfer and aeration efficiency. The main review results are, that higher values of specific oxygen absorption can be obtained at higher diffuser density; secondly, the volumetric oxygen transfer rate VOTR [g/m3·h] is higher with increasing depth of submergence at the same air flow rate. Also it can be stated that with greater depth of submergence the specific oxygen absorption [g/m3·m at STP] is reduced. Dependent on the air flow rate and the pressure head, the energy consumption [Wh/m3·m at STP] of the blowers used in wastewater treatment plants is different. For example, the energy consumption varies from 4.3 [Wh/m3·m at STP] (positive displacement blower) to 3.0 [Wh/m3·m at STP] (turbo-compressors) at a pressure of 10 m and an air flow rate of 5,000 m3/h at STP.
From the results of the literature review the following conclusions can be drawn: (1) High specific oxygen absorption values (SOA) [g/m3·m at STP] can be achieved applying shallow tanks, high diffuser densities and low specific air flow rates; (2) High aeration efficiencies (AE) [kg/kWh] can be obtained by applying high volumetric oxygen transfer rates and adequate selection of the blowers used at the wastewater treatment plants.
Nitrogen and phosphorus losses from agriculture into surface waters; the effects of policies and measures in the Netherlands
Authors: Oenema O. , Roest C. W. J. 
Published: May 2018

The increased input of fertilizers and animal wastes after 1950 has boosted agricultural crop production to a high level in many industrialized countries, but it has also contributed to increased nitrogen and phosphorus emissions from agriculture to groundwaters and surface waters. This paper summarizes the pathways and controls of nitrogen and phosphorus losses to surface waters, and it presents estimates and predictions of the losses from agricultural soils in The Netherlands into surface waters, before and after the implementation of policies and measures to reduce nutrient losses from agriculture.
Implementation of the nutrient accounting system MINAS, aiming at a step-wise lowering of nitrogen and phosphorus surpluses at farm level, will decrease the total nitrogen and phosphorus surpluses between the years 1985 and 2008 by 58 and 82%, respectively. These large decreases are the result of a strong decrease in the input via fertilizers and animal wastes, combined with only a minor decrease in the output via harvested products. Nitrogen emissions from agricultural land to surface waters will decrease by 38% between 1985 and 2008. Phosphorus emissions from agricultural land to surface waters are expected not to decrease on the short term.
Design and operation of a wastewater treatment plant treating low concentration of municipal wastewater
Authors: Duanyao Jin , Baozhen Wang , Lin Wang 
Published: May 2018

The Zhen'an Wastewater Treatment Plant in Foshan City, Guangdong Province, China is a newly built large municipal wastewater treatment plant in south China, situated in the southeast of the famous ancient Foshan City, has a treatment capacity of 100,000 m3/d, serves an area of 32 km2 and 220,000 P. E., occupies 7 ha area with a total investment of 220 million RMB (about 26.5 million U.S dollar), which was put into operation in December 1995.
As it is difficult to design and operate the wastewater treatment plant because of the low organic concentration of its influent, the simplified A/O activated sludge process without primary treatment for simultaneous removal of phosphorus and ammonia nitrogen was employed to design the plant, by which, the wastewater is treated very well, with higher effluent quality than the traditional activated sludge process, while the capital and O/M costs are lower than the latter.
Ecologically based standards for nutrients in streams and ditches in The Netherlands
Authors: Peeters Edwin T. H. M. , Gardeniers Jean J. P. 
Published: May 2018

General and specific water quality standards were formulated on a national scale in The Netherlands in the eighties of this century. A general environmental quality was defined as the minimum acceptable water quality level for all inland waters. For this quality level, standards for total phosphorus and total nitrogen were derived from measurements in shallow lakes sensitive to eutrophication for this quality level. No standards were developed for specific environmental quality.
In this study we tested whether single nutrient standards are sufficient to guarantee the minimum quality level in streams and ditches. We also investigated whether specific environmental quality requires specific standards. We, therefore, analyzed data collected by regional waterboards in The Netherlands.
The results show that nutrient standards for the general quality are not sufficient to guarantee the minimum quality for all water types. They do not provide appropriate protection for aquatic life. More specific standards should be set to protect and preserve the full biodiversity of ditches and streams.
Setting a single standard for general environmental quality and one for specific environmental quality for all types of water is not defendable. Different types of water have different aquatic communities and different nutrient levels. It is therefore recommended that water type dependent standards should be developed. In this study, standards for both general and specific environmental quality in respect to nutrients are proposed for six stream types and for six ditch types.
A new direction in the urban runoff and pollution management in the city of Bergen, Norway
Authors: Thorolfsson Sveinn T. 
Published: May 2018

This paper deals with the new direction in the urban runoff and water environment master planning for the Municipality of Bergen, Norway. The goal is to manage the runoff (wastewater and storm water) in a way that environmental damages are avoided at lowest possible costs. The plan is partly based on the findings in the research program carried out in the Birkeland basin and the subcatchment Sandsli in Bergen since 1981. The solution to the surface water management requires the use of a source control of the water quantity and quality combined with the green trends in the urban storm water management to utilise the capabilities of the urban nature to take up the storm water and to reduce the pollution content in the water. The interaction between the research and the master plan is outlined. In the planning process brooks, rivers and lakes were kept as natural as possible.
In evaluating alternative solutions for the urban runoff in the Birkeland basin, the need for better design values and experiences became apparent. Therefore, a research program was started in Birkeland basin and in Sandsli urban hydrological research catchment. The findings in Birkeland and Sandsli have provided valuable data and experiences to the master plan.
Particle and micro-organism removal in conventional and advanced treatment technology
Authors: Graveland A. 
Published: May 2018

All international drinking water quality standards can be divided into four groups
– (micro)biological: bacteria, viruses, cysts, higher organisms, etc.
– toxicological: THM, AOX, pesticides, solvents, etc.
– organoleptic (esthetic): taste, odor, color, turbidity, etc.
– operational: DOC, AOC, pH, Ca2+, HCO3−, Cl−, SO42−, etc.
The philosophy on drinking water treatment focuses on the removal of all the undesired species, dissolved and undissolved, available in raw water, in such a way that no new undesired compounds are introduced during treatment such as Al, Cl2, THM, AOX and AOC or during distribution such as Pb, Cu, Cd and asbestos. Special attention is paid to the removal of organic and inorganic colloids and of micro-organisms. Microbiologically stable water during storage and distribution can be realized by removal of nutrients (DOC, AOC) without the use of chlorine of chlorine products.
As an example the treatment systems of the Amsterdam Water Supply based on the relatively very polluted raw water of the river Rhine are described. For future expansion of the production capacity membrane processes such as hyperfiltration (HF), electrodialysis reversal (EDR) and ultrafiltration (UF) are investigated.
Results are shown on conventional and advanced technology concerning: final water quality, natural and environmental protection, process stability and costs per m3.
Systems approach to effective water quality management in the Republic of South Africa, existing situation and expected future developments
Authors: Marjanovic P. , Miloradov M. , van Zyl F. 
Published: May 2018

The new National water policy will change the way water quality is managed in South Africa. The paper considers the water policy and the repercussions it will have for water quality management in South Africa and proposes a system that can be used to come up with optimum solutions for water quality management. The proposed solution integrates policy and institutional arrangements with the Cadastral system for point and non point sources of pollution and optimisation tools to ensure optimal management of water quality at any given time.
The water quality management functions catered for by the proposed system are: resource allocation for pollution discharge, water quality protection, water quality monitoring, planning, development and operation.
Influence of dissolved oxygen on nitrification kinetics in a circulating bed reactor
Authors: Lazarova V. , Nogueira R. , Manem J. , Melo L. 
Published: May 2018

The influence of dissolved oxygen concentration in nitrification kinetics was studied in a new biofilm reactor, the circulating bed reactor (CBR). The study was carried out partly at laboratory scale with synthetic water containing inorganic carbon and nitrogen compounds, and partly at pilot scale for secondary and tertiary nitrification of municipal wastewater.
The experimental results showed that either the ammonia or the oxygen concentration could be limiting for the nitrification rate. The transition from ammonia to oxygen limiting conditions occurred for an oxygen to ammonia concentration ratio of about 1.5 - 2 gO2/gN-NH4+ for both laboratory- and pilot-scale reactors. The nitrification kinetics of the laboratory-scale reactor was close to a half order function of the oxygen concentration, when oxygen was the rate limiting substrate.
Ecotoxicity of contaminated sediments, a matter of bioavailability
Authors: Kaag N. H. B. M. , Foekema E. M. , Scholten M. C. Th. 
Published: May 2018

Marine and freshwater mesocosm-scale experiments with contaminated sediments have shown that there is a direct relationship between the accumulated contaminant levels and the feeding habits of the organisms used. The highest levels of PAHs and PCBs were found in the sediment feeding lugworm Arenicola marina and in Tubifex worms. The levels of contaminants in the suspension feeding mussels Mytilus edulis and the zebra mussels, Dreissena polymorpha, were not influenced by the contaminant content of the sediments, but were related instead to the level of contaminants in the sea water above. Intermediate levels were found in the baltic tellin, Macoma balthica, which is a filter feeder as well as a deposit feeder, depending on the availability of food.
These results show that there is no simple relationship between contaminant concentration in the sediments and bioavailability. Higher levels of contaminants do not necessarily lead to higher levels of these contaminants in Arenicola, due to differences in the sediment structure and the ageing of the contamination. On the other hand, toxic effects are related to the internal concentrations of certain chemicals. The internal concentrations observed in Arenicola may provide a good estimation of the true bioavailability of sedimentary contaminants and can also be used as an indicator for potential environmental effects.
Water, soil and chemical losses: field experiments and model analysis
Authors: Pisa P. Rossi , Preti F. , Rossi M. , Ventura F. , Mazzanti B. 
Published: May 2018

The study of the environmental impact of water erosion, chemicals and nutrient transport by runoff water is very important to protect soil and water quality. It is possible to find much literature on this topic, but the survey data lack uniformity and represent many different agronomic or natural environments. This is due to the wide range of parameters involved in these phenomena, such as soil and geomorphologic characteristics, tillage and crop management, nutrients and pesticides used.
Results of some experiments are presented in this paper. A comparison of water, soil and chemical losses has been made between experimental data and modeling outputs, both at plot and at watershed scale. The findings indicate that monitoring and modeling are two complementary instruments, both necessary for the analysis of agrochemical transport phenomena, and that the proposed methodology is useful to evaluate the related environmental impact under different scenarios.
Domestic Effluent Treatment through Integrated System of Septic Tank and Root Zone
Authors: Philippi Luiz S. , da Costa Rejane H. R. , Sezerino Pablo H. 
Published: May 2018

According to national statistical data, only 10% of the Brazilian urban population have their sewage treated. In the rural areas, where people usually treat sewage trough septic tank systems, this value is not greater than 5%. This situation, therefore, depicts a lack of basic sanitation in Brazil, which, in turn, is responsible for the utilisation of individual systems for the treatment of sewage by more than 100 million people. Generally, soils and water rivers are, no longer, the last fate for the discharged effluents. Wetland system for the treatment of domestic sewage have been employed in different situations and arrangements (combined system) always showing outstanding performances.
The reasons which qualify this system for the treatment of effluents have been attributed to its low cost, easy maintenance and operation.
The experiment was carried out in the Agriculture Secretary's Training Center, Santa Catarina State, responsible for servicing approximately 66 people daily, and was fed with local effluent.
This work assesses the efficacy of such a kind of system, which is composed of a septic tank followed by the root zone, in the treatment of liquid effluents.
Closed soilless growing systems: a sustainable solution for dutch greenhouse horticulture
Authors: Van Os Erik A. 
Published: May 2018

Dutch greenhouse growers are obliged to invest in environmental friendly cropping systems, in order to comply with new legislation. Closed soilless growing systems may lead to environmental friendly systems and thus to a sustainable horticultural sector. This paper encompasses the change from general to specific legislation, the availability of good water and the developments in disinfection of nutrient solutions. For the latter, the interest of growers in the possibilities of slow sand filtration to disinfect the nutrient solution will be discussed.
In the last ten years there has been an awakening of environmental consciousness in society. Agriculture and horticulture have had to face their polluting aspects too, such as the discharge of nutrients, the emission of pesticides and the waste of materials such as plastics and substrates for cultivation. Initial legislation was rather rough and not based on research. Later, forced by court judgments and social pressure, new regulations have set a timetable for all nurseries to adopt specific measures in order to decrease the leaching of water and fertilisers into the environment. A recent covenant between horticultural employers and the Dutch government for a sustainable development of greenhouse horticulture between 2000 and 2010 enables the growers to achieve the environmental targets in their own way, if they make a specific plan for their nurseries.
Closed growing systems prevent the leaching of chemicals into the environment; in Dutch situations leaching into ground and surface water. Studies showed savings of up to 30% of water and up to 40% of fertilisers in closed systems compared to traditional open systems. A 100% efficiency of water and nutrients often cannot be achieved, because of the relatively poor water quality of the supply water. Mostly the sodium content of the water eventually becomes too high, and, consequently, part of the nutrient solution should be discharged.
Closed growing systems bear the risk of dispersal of pathogens all over the nursery. Therefore, it is always said in the Netherlands that disinfection of the recirculating nutrient solution is a necessity for long-term crops to avoid a disaster due to an outbreak of root-borne diseases. However, existing, active, sterilisation systems are not always applied, mainly because of the high costs. Now, developments in passive disinfection equipment focus on the removal of pathogens without a complete sterilisation of the nutrient solution. Investigations into the prospects of slow sand filtration as a cheap, robust disinfection method for a number of major pathogens have proved its feasibility on a small scale.
Future trends are scaling-up and inter-farm co-operation to achieve a sustainable use of water and nutrients to minimise contamination of ground and surface water. Economic prospects are still the most important motive to change the traditional way of growing.
Environmental study of the alternatives for the sewer system of a small coastal community in the bay of Biscay
Authors: Alvarez C. , Juanes J. A. , Revilla J. A. , Koev K. , Roldan A. , Ivanov V. 
Published: May 2018

Zumaia is a small tourist community on the northern coast of Spain, situated along the estuary of the Urola river. This ecosystem has been affected by urban discharges coming from the villages surrounding the estuary. According to the 91/271 European Community Directive, regarding wastewater treatment, this situation should be addressed in order to achieve the quality objectives established for the restoration of the natural values of the area. The local Water Authorities of the Basque Country (Spain) have adopted an integrated model for the design of the sewer system of this community. The model was developed specifically for the study of coastal sewerage under dominant wet weather conditions and includes: 1) Establishment of the site specific statutory requirements and environmental objectives; 2) Design of sewer system components with specific reference to influences on marine water quality; 3) Development of monitoring programs.
The construction of a sewer pipe alongside the river to collect the foul and the stormwater flow will prevent a large proportion of the discharges of contaminants into the receiving waters. However, the presence of overflows in the system during storms leads to the release of a great deal of pollutants into these waters. The main problems related to this type of discharge in the littoral zone arise from the bacteriological contamination of the bathing waters and from the oxygen depletion over the estuary. These two topics have been the predominant issues conditioning the consideration of different schemes of management of the sewer system. The aim of this paper is to analyze, from an environmental point of view, the structural and functional scheme considered for the sewage management of this community.
Modifications of rainfall runoff and decision finding models for on-line simulation in real time control
Authors: Cassar Andreas , Verworn Hans-Reinhard 
Published: May 2018

Most of the existing rainfall runoff models for urban drainage systems have been designed for off-line calculations. With a design storm or a historical rain event and the model system the rainfall runoff processes are simulated, the faster the better. Since very recently, hydrodynamic models have been considered to be much too slow for real time applications. However, with the computing power of today - and even more so of tomorrow - very complex and detailed models may be run on-line and in real time. While the algorithms basically remain the same as for off-line simulations, problems concerning timing, data management and inter process communication have to be identified and solved.
This paper describes the upgrading of the existing hydrodynamic rainfall runoff model HYSTEM/EXTRAN and the decision finding model INTL for real time performance, their implementation on a network of UNIX stations and the experiences from running them within an urban drainage real time control project. The main focus is not on what the models do but how they are put into action and made to run smoothly embedded in all the processes necessary in operational real time control.