The need for an advanced and even far reaching phosphorus removal at municipal WWTPs may soon get stipulations in relation to a reuse of phosphorus (P). This paper discusses the possible ways to remove phosphorous fro...The need for an advanced and even far reaching phosphorus removal at municipal WWTPs may soon get stipulations in relation to a reuse of phosphorus (P). This paper discusses the possible ways to remove phosphorous from municipal wastewater. This is already an established demand in many countries. However, as P is a limited raw material, this need for a reuse of P will become an example of what now is labelled “cyclic economy”. For instance, a national demand from the German state is already put in force. In this perspective the advanced filtration techniques will play an interesting role, and most possibly a crucial role. Examples are presented from several municipal WWTPs already in operation with a final polishing treatment step based on chemical precipitation and separation of phosphorus. Typical stable discharge P levels are found at these plants at levels < 0.05 to 0.10 ppm. The new demands on phosphorus recovery will also call for modified process concepts for the WWTP;for instance, a refined biological phosphorus removal (EBP) attains more attention and he needed very low discharge levels of P, where the enhanced P-removal will include different smart filtration techniques.展开更多
The very long tradition of the activated sludge treatment model within the water industry has demonstrated very versatile possibilities to adopt the operation mode for different enhancements. By looking into other tre...The very long tradition of the activated sludge treatment model within the water industry has demonstrated very versatile possibilities to adopt the operation mode for different enhancements. By looking into other treatment models within the activated sludge family it is possible to find alternatives for the operation. This paper concentrates on the possibilities to improve even small WWTP with respect to energy savings. The small plant in Northern Sweden, called Rosvik WWTP, is given as an example. Some important findings related to the intermittent aeration mode may be summarized as follows: 1) An energy savings for the operation of the small WWTP with respect to aeration needs that resulted in a decrease of the energy power supply by more than 35%, as compared with the previous operation based on continuous aeration;2) The up to date effluent levels with respect to the main pollutants have remained at very good levels in 2020, P-level averages 0.16 mg P/l versus consent level <</span><span> </span><span style="font-family:Verdana;">0.5 mg P/l;COD-level 40 versus <</span><span> </span><span><span style="font-family:Verdana;">70 mg/l and BOD</span><sub><span style="font-family:Verdana;">7</span></sub><span style="font-family:Verdana;"> 9 versus <</span></span><span> </span><span><span style="font-family:Verdana;">15 mg/l;3) Sometimes, also improved sludge settling characteristics have been observed, thus providing improved discharge figures;4) The potential to develop an enhanced biological phosphorus removal. There are however </span><span style="font-family:Verdana;">some needed conditions to accomplish these improvements: 1) Reliable</span><span style="font-family:Verdana;"> on-line probes for both oxygen control, SS-concentration control and optionally also for nitrogen control;2) A flexible automation system that allows the needed process modifications to take place;3) And finally, very important dedicated and competent plant operators, with the needed curiosity for operation improvements.展开更多
Water environmental control and process refinement inside a wastewater treatment plant (WWTP) is fundamentally based on sampling, analysis and on-line measurements on water and sludge streams. The problems related to ...Water environmental control and process refinement inside a wastewater treatment plant (WWTP) is fundamentally based on sampling, analysis and on-line measurements on water and sludge streams. The problems related to an accurate and reliable control and thus an efficient water protection are addressed in the following. Four different crucial points whenever a sampling and control scheme is planned: 1) Where should a sampling and on-line measurement take place? 2) When should sampling take place? 3) How should the sampling and on-line measurement take place? 4) Which variables should be controlled? Examples are given from different plants demonstrating ways to address the questions. Especially the relevance of the adopted parameter BOD (Biochemical Oxygen Demand) is discussed. It is finally suggested to even abandon the use of BOD as consent variable in favor of on-line measurement of Suspended Solids, Nitrogen and Phosphorous.展开更多
Water quality protection in Sweden has a more than 80-year history. The needed knowledge has by large been imported. Now, to some extent the development of phosphorus removal technology may be Swedish contribution to ...Water quality protection in Sweden has a more than 80-year history. The needed knowledge has by large been imported. Now, to some extent the development of phosphorus removal technology may be Swedish contribution to advanced knowledge. This paper presents the development in Sweden, mainly a close to 50-year period. Starting in the late 1960s, a standard of <0.5 mg P/l was the normally raised effluent criteria, regardless of the magnitude of the discharge flow. The successive sharpening of the discharge levels has today resulted in a level of 0.2 to 0.3 mg P/l typically. As a matter of fact, even levels of 0.1 to 0.15 mg P/l have been discussed. The period should a large extent demonstrated both improved technologies and a far better efficiency with respect to the use of chemicals and energy. Some important points in this development may be the understanding of the Oxygen Consumption Potential, as well as the identified needs for an improved nitrogen removal. Lately the problems of complex pollution agents and predominantly the remains of pharmaceutical agents have been identified. To illustrate the development during the 50-year period, two examples are presented from the Swedish context. The main conclusion in this paper is that the Swedish history on phosphorus removal illustrates how empirical science in practice sometimes works, including a never-ending need for an open mind and a readiness to take revised and improved knowledge on board.展开更多
The sanitation and environmental problems related to human activities can be traced at least around 2 500 years back, with written evidences both in the Old Testimony and the Greek culture. Thus in this perspective th...The sanitation and environmental problems related to human activities can be traced at least around 2 500 years back, with written evidences both in the Old Testimony and the Greek culture. Thus in this perspective the matter is by convention an acknowledged problem since long. On the other hand our modern treatment systems of wastewater have far more recent roots. As an example, this year the very widespread biological treatment based on activated sludge celebrates it 100 year anniversary. In this perspective we may see a fundamental need to discuss and scrutinize the current systems in a “sustainable” perspective. A challenge for the technical society is to provide some “quantified” criteria on the concept sustainability. The wastewater treatment systems as we know them and develop them may be addressed by applying four major “sustainability” criteria: 1) The sustainability from major sanitation viewpoints;2) The sustainability from environmental viewpoints;3) The financial sustainability for the technical systems;(4) The sustainability with respect to adopting the systems into a more or less consistently changing society.展开更多
The question of wastewater treatment and control is reflected from a very specific viewpoint: the low priority given to accurate and useful measurements within wastewater treatment. The matter is discussed from four v...The question of wastewater treatment and control is reflected from a very specific viewpoint: the low priority given to accurate and useful measurements within wastewater treatment. The matter is discussed from four various perspectives, that may be labelled “Legal understanding”;“Needs for accurate measurement results already in the planning and design stage”;“The measurement problem and human behaviour”;“The understanding of the short term and long term dynamics and changes in pollution and flow loads on a wastewater treatment plant (WWTP)”. All these aspects bring about much improved needs for an accurate and frequent measurement scheme both for pollutants and flows entering a WWTP. The conclusion is stated as follows: A far more and well elaborated on-line measurement system at the plants would become a needed tool for improved water environment protection at lower costs.展开更多
文摘The need for an advanced and even far reaching phosphorus removal at municipal WWTPs may soon get stipulations in relation to a reuse of phosphorus (P). This paper discusses the possible ways to remove phosphorous from municipal wastewater. This is already an established demand in many countries. However, as P is a limited raw material, this need for a reuse of P will become an example of what now is labelled “cyclic economy”. For instance, a national demand from the German state is already put in force. In this perspective the advanced filtration techniques will play an interesting role, and most possibly a crucial role. Examples are presented from several municipal WWTPs already in operation with a final polishing treatment step based on chemical precipitation and separation of phosphorus. Typical stable discharge P levels are found at these plants at levels < 0.05 to 0.10 ppm. The new demands on phosphorus recovery will also call for modified process concepts for the WWTP;for instance, a refined biological phosphorus removal (EBP) attains more attention and he needed very low discharge levels of P, where the enhanced P-removal will include different smart filtration techniques.
文摘The very long tradition of the activated sludge treatment model within the water industry has demonstrated very versatile possibilities to adopt the operation mode for different enhancements. By looking into other treatment models within the activated sludge family it is possible to find alternatives for the operation. This paper concentrates on the possibilities to improve even small WWTP with respect to energy savings. The small plant in Northern Sweden, called Rosvik WWTP, is given as an example. Some important findings related to the intermittent aeration mode may be summarized as follows: 1) An energy savings for the operation of the small WWTP with respect to aeration needs that resulted in a decrease of the energy power supply by more than 35%, as compared with the previous operation based on continuous aeration;2) The up to date effluent levels with respect to the main pollutants have remained at very good levels in 2020, P-level averages 0.16 mg P/l versus consent level <</span><span> </span><span style="font-family:Verdana;">0.5 mg P/l;COD-level 40 versus <</span><span> </span><span><span style="font-family:Verdana;">70 mg/l and BOD</span><sub><span style="font-family:Verdana;">7</span></sub><span style="font-family:Verdana;"> 9 versus <</span></span><span> </span><span><span style="font-family:Verdana;">15 mg/l;3) Sometimes, also improved sludge settling characteristics have been observed, thus providing improved discharge figures;4) The potential to develop an enhanced biological phosphorus removal. There are however </span><span style="font-family:Verdana;">some needed conditions to accomplish these improvements: 1) Reliable</span><span style="font-family:Verdana;"> on-line probes for both oxygen control, SS-concentration control and optionally also for nitrogen control;2) A flexible automation system that allows the needed process modifications to take place;3) And finally, very important dedicated and competent plant operators, with the needed curiosity for operation improvements.
文摘Water environmental control and process refinement inside a wastewater treatment plant (WWTP) is fundamentally based on sampling, analysis and on-line measurements on water and sludge streams. The problems related to an accurate and reliable control and thus an efficient water protection are addressed in the following. Four different crucial points whenever a sampling and control scheme is planned: 1) Where should a sampling and on-line measurement take place? 2) When should sampling take place? 3) How should the sampling and on-line measurement take place? 4) Which variables should be controlled? Examples are given from different plants demonstrating ways to address the questions. Especially the relevance of the adopted parameter BOD (Biochemical Oxygen Demand) is discussed. It is finally suggested to even abandon the use of BOD as consent variable in favor of on-line measurement of Suspended Solids, Nitrogen and Phosphorous.
文摘Water quality protection in Sweden has a more than 80-year history. The needed knowledge has by large been imported. Now, to some extent the development of phosphorus removal technology may be Swedish contribution to advanced knowledge. This paper presents the development in Sweden, mainly a close to 50-year period. Starting in the late 1960s, a standard of <0.5 mg P/l was the normally raised effluent criteria, regardless of the magnitude of the discharge flow. The successive sharpening of the discharge levels has today resulted in a level of 0.2 to 0.3 mg P/l typically. As a matter of fact, even levels of 0.1 to 0.15 mg P/l have been discussed. The period should a large extent demonstrated both improved technologies and a far better efficiency with respect to the use of chemicals and energy. Some important points in this development may be the understanding of the Oxygen Consumption Potential, as well as the identified needs for an improved nitrogen removal. Lately the problems of complex pollution agents and predominantly the remains of pharmaceutical agents have been identified. To illustrate the development during the 50-year period, two examples are presented from the Swedish context. The main conclusion in this paper is that the Swedish history on phosphorus removal illustrates how empirical science in practice sometimes works, including a never-ending need for an open mind and a readiness to take revised and improved knowledge on board.
文摘The sanitation and environmental problems related to human activities can be traced at least around 2 500 years back, with written evidences both in the Old Testimony and the Greek culture. Thus in this perspective the matter is by convention an acknowledged problem since long. On the other hand our modern treatment systems of wastewater have far more recent roots. As an example, this year the very widespread biological treatment based on activated sludge celebrates it 100 year anniversary. In this perspective we may see a fundamental need to discuss and scrutinize the current systems in a “sustainable” perspective. A challenge for the technical society is to provide some “quantified” criteria on the concept sustainability. The wastewater treatment systems as we know them and develop them may be addressed by applying four major “sustainability” criteria: 1) The sustainability from major sanitation viewpoints;2) The sustainability from environmental viewpoints;3) The financial sustainability for the technical systems;(4) The sustainability with respect to adopting the systems into a more or less consistently changing society.
文摘The question of wastewater treatment and control is reflected from a very specific viewpoint: the low priority given to accurate and useful measurements within wastewater treatment. The matter is discussed from four various perspectives, that may be labelled “Legal understanding”;“Needs for accurate measurement results already in the planning and design stage”;“The measurement problem and human behaviour”;“The understanding of the short term and long term dynamics and changes in pollution and flow loads on a wastewater treatment plant (WWTP)”. All these aspects bring about much improved needs for an accurate and frequent measurement scheme both for pollutants and flows entering a WWTP. The conclusion is stated as follows: A far more and well elaborated on-line measurement system at the plants would become a needed tool for improved water environment protection at lower costs.
