By the observation and evaluation of the microscopic picture of activated sludge samples it is po... more By the observation and evaluation of the microscopic picture of activated sludge samples it is possible to introduce another biological parameter additional to conventional physico-chemical parameters for the control of biological stages of waste water treatment plants. Considering the fact that parameters like floc size and floc size distribution, structure of the flocs (compact/open), shape of the flocs (round/irregular) allow perceptions of the adjusted operation conditions of the biological stages, evidence for changing operation conditions or threatening operation disturbances can be recognised. This recognition takes place at a very early phase, because the morphology of activated sludge flocs reacts very fast to changing conditions. An automatic image analysis of activated sludge floc pictures would enable the introduction of a new sum parameter to enhance operation control of aeration tanks. By a statistical evaluation of the processed sludge images several parameters can be...
Da die derzeitige Abwasserreinigung nicht für die Elimination von Mikroschadstoffen ausgelegt ist... more Da die derzeitige Abwasserreinigung nicht für die Elimination von Mikroschadstoffen ausgelegt ist, gelangen diese unter anderem aus dem kommunalen Abwasser über die Kläranlagen in die aquatische Umwelt. Das Projekt MicroStop untersucht eine Kombination von einem Festbettreaktor und einer Nanofiltrationsanlage zur Elimination von Mikroschadstoffen. Die Versuche zeigen, dass durch die Nanofiltration im Durschnitt über 95 % der ausgewählten, detektierten Mikroschadstoffe eliminiert werden können und dieses Verfahren somit eine geeignete Barriere für diese Schadstoffe darstellt. Parallel zu den Nanofiltrationsversuchen wird der biologische Abbau von Mikroschadstoffen in zwei Festbettreaktoren untersucht. Die Versuchsergebnisse zeigen, dass ein signifikanter biologischer Abbau verschiedener Mikroschadstoffe in den Reaktoren stattfindet.Since the current wastewater-treatment plants are not designed for the elimination of micropollutants, these are released into the aquatic environment. The MicroStop project investigates a combination of a fixed-bed reactor and a nanofiltration plant for the elimination of micropollutants. The experiments show that nanofiltration can eliminate on average over 95% of the selected, detected micropollutants and that this process therefore represents a suitable barrier for these pollutants. Parallel to the nanofiltration experiments, the biological degradation of micropollutants is being investigated in two fixed-bed reactors. The test results show that a significant biological degradation of various micropollutants takes place in the reactors.Hamburg Wasser Rosa-Luxemburg Stiftun
Agroforestry is the inclusion of trees or other woody perennial plants into agricultural systems,... more Agroforestry is the inclusion of trees or other woody perennial plants into agricultural systems, including crop and livestock production. It can also be seen as a combination of agriculture and forestry. While conventional large scale agriculture is mainly concerned with maximising short term yields, agroforestry has the objective of emulating natural ecosystems in order to realise a number of ecosystem services. Those include the protection of soil against erosion and water-logging, minimising evaporation of water from soil and plants by decreasing wind speed, water protection through deeper and more extensive root systems and increased biodiversity. Long term stability and productivity of agroforestry systems surpasses those of conventional monocultures or pasturelands, as they tend to be more resilient, but the establishment of trees on farmland comes with certain challenges. Until the trees start to pay off, several years or even decades might pass. The right combination of tre...
This paper describes a new wastewater treatment concept which was assessed to be technically and ... more This paper describes a new wastewater treatment concept which was assessed to be technically and economically feasible for suburban and rural areas in Mediterranean countries. The treatment consists of a two-step anaerobic high-rate reactor like UASB reactor followed by vertical flow constructed wetland (CW) and UV radiation. It fulfills the defined criteria, as meeting the standards for water reuse, costs especially for energy are low, sewage sludge production is limited and operation and maintenance are simple. Although there are much experience and data available about design and operation of CW and UV radiation, the knowledge about anaerobic treatment of municipal wastewater in UASB reactor at moderate temperature is limited. Therefore bench-scale experiments with pre-settled high-strength municipal wastewater were carried out in a one step UASB reactor of 55 liters. The results show a satisfactory effluent quality at fluctuating HRT. During 9 months of continuous operation, tot...
Source control of industrial wastewater including separate treatment and reuse of water and subst... more Source control of industrial wastewater including separate treatment and reuse of water and substances has become a standard in many companies in industrialized countries. Numerous methods are available for further evaluation of the ecological efficiency of the overall production process. The next step involves consideration of the production process in its entirety. Companies have efficient devices for treatment and reuse of water and substances. An integrated assessment can determine whether realization of a wastewater-free factory is possible. Certain production concepts may appear to be unfeasible even from an ecological point of view. It is worthwhile in such cases to consider creative solutions involving alternative production processes including new products as shown by the international organization ZERI (Zero Emissions Research and Initiatives, Pauli 1998). Technology is not the primary obstacle blocking more rapid dissemination of progressive concepts. Widespread acceptanc...
The fact from the United Nations that in 2015, about 663 million people worldwide did not have ac... more The fact from the United Nations that in 2015, about 663 million people worldwide did not have access to an improved drinking water source, does not resemble the reality wherein more than 1.8 billion people worldwide were consuming water which is unsafe for drinking. Nanofiltration, with the ability to reject several trace organic compounds, heavy metals and viruses at a lower energy demand than reverse osmosis, has found application for the production of high quality drinking water in developed nations. This study briefly reviewed the efficacy of nanofiltration for drinking water production considering various types of pollutants. Series of experiments were conducted using a pilot-scale nanofiltration unit, to assess the potential for drinking water production, from ground water, in a developing country like Ghana and to estimate the associated costs. The economic feasibility of a micro-enterprise (relying on nanofiltration) was evaluated for tackling the economic water scarcity in...
By the consideration of the microscopic picture of activated sludge samples it is possible to int... more By the consideration of the microscopic picture of activated sludge samples it is possible to introduce a further biological parameter apart from the conventional physico-chemical parameters for the evaluation and control of biological stages of waste water treatment plants. It is reported that different parameters have certain influences on the activated sludge floc and on the developing biozenosis. An automatical image analysis of activated sludge floc pictures with the support of algorithms of the digital image processing would enable the introduction of a new sum parameter to support operation control of aeration tanks. By means of the microscopic image possible threatening operational disturbances can be discovered before this is possible with the conventional physico-chemical parameters. In particular, the early automatic recognition of f irst signs of bulking sludge and swimming sludge caused by the excessive growth of f ilamentous microorganisms represents an important instr...
Fixed-bed reactor (FBR) is a promising technology for realising robust high-rate nitrification. O... more Fixed-bed reactor (FBR) is a promising technology for realising robust high-rate nitrification. Only a few studies have investigated the effect of salinity on these systems. In this research work, the effect of gradual stepwise increase in chloride concentration (NaCl content) on the performance of high-rate nitrifying FBRs was studied at loading rates of about 1 kg NH4+-N∙m-3∙d-1 at 25 °C. Two lab-scale FBRs having stable biofilms (adapted to 4 g Cl-/L) grown on commercial media - plastic carrier fed with nanofiltration (NF) permeate of a landfill leachate concentrate, and clay beads fed with synthetic saline wastewater, respectively - were operated using up-flow velocities (u) of about 12 and 8 m/h, respectively, for a period of about 100 days, wherein the chloride content of the feed water was increased from 4 to 16 g/L (electrical conductivity: 13-45 mS/cm). On an average, the FBR packed with plastic carriers (u ≈ 12 m/h) offered ammonia removal percentages greater than 97%, whereas the FBR filled with clay beads due to its low bed porosity (and therefore, u ≈ 8 m/h only) gave nitrification efficiencies of about 70% only. The organic compounds contained in the NF permeate were found to temporarily inhibit the nitrifiers (causing nitrite accumulation), whereas the ammonia removed in the clay beads-packed FBR was transformed almost entirely into nitrate. Increase in chloride content did not have any observable detrimental effect on the performance of the reactors.
Abstract Due to high specific surface area, high biomass concentration and handling convenience, ... more Abstract Due to high specific surface area, high biomass concentration and handling convenience, packed bed reactor technology is a highly competitive option for nitrification of landfill leachates. Nitrification would solve the problem of insufficient ammonia retention faced by the high pressure membrane systems at the Ihlenberg landfill, which aims to achieve clean water recoveries up to 95%. This study investigated the feasibility for ammonia removal using four lab-scale reactors packed with three different packing materials (coke, expanded clay beads and polyethylene carrier) over a period of about 400 days. The research work studied the nitrification of two process streams: reverse osmosis concentrate (RO) of raw leachate (having high dissolved organics content) and nanofiltration permeate of RO retentate (with a low concentration of organics), to identify advantages/disadvantages arising from the differences in their composition. The organics contained in the leachate were observed to cause inhibition. Due to this reason, the maximum nitrification rate obtained in the presence of organics was about 570 g N-NH4+/(m3 d), whereas in their absence up to 1.2 kg N-NH4+/(m3 d) could be achieved. Although coke packing because of its higher specific surface area and rugged surface favoured faster biofilm development; due to its ability to adsorb organics and thus also promoting the growth of heterotrophs, it was found to be more vulnerable to clogging.
RUVIVAL Publication Series is a compilation of literature reviews on topics concerned with the re... more RUVIVAL Publication Series is a compilation of literature reviews on topics concerned with the revitalisation of rural areas. RUVIVAL Publication Series is part of the e-learning project RUVIVAL and each of the three contributions in this publication is connected to further interactive multimedia material, which can be reached under www.ruvival.de. The first literature review is concerned with urine utilisation as a fertiliser in agriculture. Urine contains four important nutrients for plant growth: nitrogen (N), phosphorus (P), potassium (K) and sulphur (S) and its use as fertiliser can not only recover these nutrients, but also reduce the use of chemical fertilisers and freshwater, as well as minimise the wastewater and excreta contamination of surface and open waters. However, if not managed properly, the risk of pathogen transmission, soil salinisation and pharmaceutical contamination, as well as strong and offensive odour, can cause significant health problems and discomfort. T...
Chemical precipitation of ammonia as magnesium ammonium phosphate (MAP) from methanogenic leachat... more Chemical precipitation of ammonia as magnesium ammonium phosphate (MAP) from methanogenic leachates can be a competitive alternative to biological ammonia removal. Potential for trading of the precipitate as a fertiliser defines the economics of the process. The precipitate from a landfill leachate often containing organics and heavy metals as impurities with unknown risks limits its possibility for agricultural use. This study combines MAP precipitation with membrane processes and investigates the influence of wastewater matrix, solution pH and dosage ratio of chemicals (Mg2+ : PO43−) on the precipitate purity through lab scale semibatch experiments. Under similar experimental conditions (pH 8.5 and 1 : 1 Mg2+ : PO43− molar dosage), the precipitates from raw leachate and nanofiltration (NF) permeate showed MAP contents of 65 and 90%, respectively, correspondingly with about 8300 and 1600 mg TOC/kgprecipitate. For precipitation from NF permeate, precipitation at pH 8.0 with 1 : 1 dosage ratio and pH 8.5 with 1 : 0.9 dosage ratio gave precipitates each with about 97% purity.
By the observation and evaluation of the microscopic picture of activated sludge samples it is po... more By the observation and evaluation of the microscopic picture of activated sludge samples it is possible to introduce another biological parameter additional to conventional physico-chemical parameters for the control of biological stages of waste water treatment plants. Considering the fact that parameters like floc size and floc size distribution, structure of the flocs (compact/open), shape of the flocs (round/irregular) allow perceptions of the adjusted operation conditions of the biological stages, evidence for changing operation conditions or threatening operation disturbances can be recognised. This recognition takes place at a very early phase, because the morphology of activated sludge flocs reacts very fast to changing conditions. An automatic image analysis of activated sludge floc pictures would enable the introduction of a new sum parameter to enhance operation control of aeration tanks. By a statistical evaluation of the processed sludge images several parameters can be...
Da die derzeitige Abwasserreinigung nicht für die Elimination von Mikroschadstoffen ausgelegt ist... more Da die derzeitige Abwasserreinigung nicht für die Elimination von Mikroschadstoffen ausgelegt ist, gelangen diese unter anderem aus dem kommunalen Abwasser über die Kläranlagen in die aquatische Umwelt. Das Projekt MicroStop untersucht eine Kombination von einem Festbettreaktor und einer Nanofiltrationsanlage zur Elimination von Mikroschadstoffen. Die Versuche zeigen, dass durch die Nanofiltration im Durschnitt über 95 % der ausgewählten, detektierten Mikroschadstoffe eliminiert werden können und dieses Verfahren somit eine geeignete Barriere für diese Schadstoffe darstellt. Parallel zu den Nanofiltrationsversuchen wird der biologische Abbau von Mikroschadstoffen in zwei Festbettreaktoren untersucht. Die Versuchsergebnisse zeigen, dass ein signifikanter biologischer Abbau verschiedener Mikroschadstoffe in den Reaktoren stattfindet.Since the current wastewater-treatment plants are not designed for the elimination of micropollutants, these are released into the aquatic environment. The MicroStop project investigates a combination of a fixed-bed reactor and a nanofiltration plant for the elimination of micropollutants. The experiments show that nanofiltration can eliminate on average over 95% of the selected, detected micropollutants and that this process therefore represents a suitable barrier for these pollutants. Parallel to the nanofiltration experiments, the biological degradation of micropollutants is being investigated in two fixed-bed reactors. The test results show that a significant biological degradation of various micropollutants takes place in the reactors.Hamburg Wasser Rosa-Luxemburg Stiftun
Agroforestry is the inclusion of trees or other woody perennial plants into agricultural systems,... more Agroforestry is the inclusion of trees or other woody perennial plants into agricultural systems, including crop and livestock production. It can also be seen as a combination of agriculture and forestry. While conventional large scale agriculture is mainly concerned with maximising short term yields, agroforestry has the objective of emulating natural ecosystems in order to realise a number of ecosystem services. Those include the protection of soil against erosion and water-logging, minimising evaporation of water from soil and plants by decreasing wind speed, water protection through deeper and more extensive root systems and increased biodiversity. Long term stability and productivity of agroforestry systems surpasses those of conventional monocultures or pasturelands, as they tend to be more resilient, but the establishment of trees on farmland comes with certain challenges. Until the trees start to pay off, several years or even decades might pass. The right combination of tre...
This paper describes a new wastewater treatment concept which was assessed to be technically and ... more This paper describes a new wastewater treatment concept which was assessed to be technically and economically feasible for suburban and rural areas in Mediterranean countries. The treatment consists of a two-step anaerobic high-rate reactor like UASB reactor followed by vertical flow constructed wetland (CW) and UV radiation. It fulfills the defined criteria, as meeting the standards for water reuse, costs especially for energy are low, sewage sludge production is limited and operation and maintenance are simple. Although there are much experience and data available about design and operation of CW and UV radiation, the knowledge about anaerobic treatment of municipal wastewater in UASB reactor at moderate temperature is limited. Therefore bench-scale experiments with pre-settled high-strength municipal wastewater were carried out in a one step UASB reactor of 55 liters. The results show a satisfactory effluent quality at fluctuating HRT. During 9 months of continuous operation, tot...
Source control of industrial wastewater including separate treatment and reuse of water and subst... more Source control of industrial wastewater including separate treatment and reuse of water and substances has become a standard in many companies in industrialized countries. Numerous methods are available for further evaluation of the ecological efficiency of the overall production process. The next step involves consideration of the production process in its entirety. Companies have efficient devices for treatment and reuse of water and substances. An integrated assessment can determine whether realization of a wastewater-free factory is possible. Certain production concepts may appear to be unfeasible even from an ecological point of view. It is worthwhile in such cases to consider creative solutions involving alternative production processes including new products as shown by the international organization ZERI (Zero Emissions Research and Initiatives, Pauli 1998). Technology is not the primary obstacle blocking more rapid dissemination of progressive concepts. Widespread acceptanc...
The fact from the United Nations that in 2015, about 663 million people worldwide did not have ac... more The fact from the United Nations that in 2015, about 663 million people worldwide did not have access to an improved drinking water source, does not resemble the reality wherein more than 1.8 billion people worldwide were consuming water which is unsafe for drinking. Nanofiltration, with the ability to reject several trace organic compounds, heavy metals and viruses at a lower energy demand than reverse osmosis, has found application for the production of high quality drinking water in developed nations. This study briefly reviewed the efficacy of nanofiltration for drinking water production considering various types of pollutants. Series of experiments were conducted using a pilot-scale nanofiltration unit, to assess the potential for drinking water production, from ground water, in a developing country like Ghana and to estimate the associated costs. The economic feasibility of a micro-enterprise (relying on nanofiltration) was evaluated for tackling the economic water scarcity in...
By the consideration of the microscopic picture of activated sludge samples it is possible to int... more By the consideration of the microscopic picture of activated sludge samples it is possible to introduce a further biological parameter apart from the conventional physico-chemical parameters for the evaluation and control of biological stages of waste water treatment plants. It is reported that different parameters have certain influences on the activated sludge floc and on the developing biozenosis. An automatical image analysis of activated sludge floc pictures with the support of algorithms of the digital image processing would enable the introduction of a new sum parameter to support operation control of aeration tanks. By means of the microscopic image possible threatening operational disturbances can be discovered before this is possible with the conventional physico-chemical parameters. In particular, the early automatic recognition of f irst signs of bulking sludge and swimming sludge caused by the excessive growth of f ilamentous microorganisms represents an important instr...
Fixed-bed reactor (FBR) is a promising technology for realising robust high-rate nitrification. O... more Fixed-bed reactor (FBR) is a promising technology for realising robust high-rate nitrification. Only a few studies have investigated the effect of salinity on these systems. In this research work, the effect of gradual stepwise increase in chloride concentration (NaCl content) on the performance of high-rate nitrifying FBRs was studied at loading rates of about 1 kg NH4+-N∙m-3∙d-1 at 25 °C. Two lab-scale FBRs having stable biofilms (adapted to 4 g Cl-/L) grown on commercial media - plastic carrier fed with nanofiltration (NF) permeate of a landfill leachate concentrate, and clay beads fed with synthetic saline wastewater, respectively - were operated using up-flow velocities (u) of about 12 and 8 m/h, respectively, for a period of about 100 days, wherein the chloride content of the feed water was increased from 4 to 16 g/L (electrical conductivity: 13-45 mS/cm). On an average, the FBR packed with plastic carriers (u ≈ 12 m/h) offered ammonia removal percentages greater than 97%, whereas the FBR filled with clay beads due to its low bed porosity (and therefore, u ≈ 8 m/h only) gave nitrification efficiencies of about 70% only. The organic compounds contained in the NF permeate were found to temporarily inhibit the nitrifiers (causing nitrite accumulation), whereas the ammonia removed in the clay beads-packed FBR was transformed almost entirely into nitrate. Increase in chloride content did not have any observable detrimental effect on the performance of the reactors.
Abstract Due to high specific surface area, high biomass concentration and handling convenience, ... more Abstract Due to high specific surface area, high biomass concentration and handling convenience, packed bed reactor technology is a highly competitive option for nitrification of landfill leachates. Nitrification would solve the problem of insufficient ammonia retention faced by the high pressure membrane systems at the Ihlenberg landfill, which aims to achieve clean water recoveries up to 95%. This study investigated the feasibility for ammonia removal using four lab-scale reactors packed with three different packing materials (coke, expanded clay beads and polyethylene carrier) over a period of about 400 days. The research work studied the nitrification of two process streams: reverse osmosis concentrate (RO) of raw leachate (having high dissolved organics content) and nanofiltration permeate of RO retentate (with a low concentration of organics), to identify advantages/disadvantages arising from the differences in their composition. The organics contained in the leachate were observed to cause inhibition. Due to this reason, the maximum nitrification rate obtained in the presence of organics was about 570 g N-NH4+/(m3 d), whereas in their absence up to 1.2 kg N-NH4+/(m3 d) could be achieved. Although coke packing because of its higher specific surface area and rugged surface favoured faster biofilm development; due to its ability to adsorb organics and thus also promoting the growth of heterotrophs, it was found to be more vulnerable to clogging.
RUVIVAL Publication Series is a compilation of literature reviews on topics concerned with the re... more RUVIVAL Publication Series is a compilation of literature reviews on topics concerned with the revitalisation of rural areas. RUVIVAL Publication Series is part of the e-learning project RUVIVAL and each of the three contributions in this publication is connected to further interactive multimedia material, which can be reached under www.ruvival.de. The first literature review is concerned with urine utilisation as a fertiliser in agriculture. Urine contains four important nutrients for plant growth: nitrogen (N), phosphorus (P), potassium (K) and sulphur (S) and its use as fertiliser can not only recover these nutrients, but also reduce the use of chemical fertilisers and freshwater, as well as minimise the wastewater and excreta contamination of surface and open waters. However, if not managed properly, the risk of pathogen transmission, soil salinisation and pharmaceutical contamination, as well as strong and offensive odour, can cause significant health problems and discomfort. T...
Chemical precipitation of ammonia as magnesium ammonium phosphate (MAP) from methanogenic leachat... more Chemical precipitation of ammonia as magnesium ammonium phosphate (MAP) from methanogenic leachates can be a competitive alternative to biological ammonia removal. Potential for trading of the precipitate as a fertiliser defines the economics of the process. The precipitate from a landfill leachate often containing organics and heavy metals as impurities with unknown risks limits its possibility for agricultural use. This study combines MAP precipitation with membrane processes and investigates the influence of wastewater matrix, solution pH and dosage ratio of chemicals (Mg2+ : PO43−) on the precipitate purity through lab scale semibatch experiments. Under similar experimental conditions (pH 8.5 and 1 : 1 Mg2+ : PO43− molar dosage), the precipitates from raw leachate and nanofiltration (NF) permeate showed MAP contents of 65 and 90%, respectively, correspondingly with about 8300 and 1600 mg TOC/kgprecipitate. For precipitation from NF permeate, precipitation at pH 8.0 with 1 : 1 dosage ratio and pH 8.5 with 1 : 0.9 dosage ratio gave precipitates each with about 97% purity.
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Papers by Joachim Behrendt