Možnosti využití odpadních vodárenských kalů

This paper deals with the sludge that is produced within the treatment of water and production of drinking water. When alumina and iron coagulants are used for coagulation and clarification of surface water, mainly alumina and iron sludge are produced. This paper describes possible alumina recovery in the water treatment procedure and re-use of sludge for treatment of municipal wastewater. The sludge can be also used for production of cement. All those actions decrease the quantity of wastes and contribute to environmental protection. The waste sludge can be also used as secondary raw materials.Tento příspěvek se zabývá kaly, které vznikají v procesu úpravy vody na vodu pitnou. Jde zejména o hlinité a železité vodárenské kaly vzniklé při úpravě povrchových vod koagulací a čiřením za použití železitých a hlinitých koagulantů. Jsou uváděny možnosti využití hliníku zpět v procesu úpravy vody, využití kalů při čištění městských odpadních vod. Využití kalů při výrobě cementu. Důvodem pro takové postupy je snižování objemu odpadu, a tím ochrana životního prostředí. Dále pak využití odpadních kalů jako druhotné suroviny

Some solutions to respond climate change for the Mekong Delta, Viet Nam

In the recent decades, the Mekong River Delta has suffered quite significant impacts of climate change. Fluctuations of weather elements and sea level rises have caused adverse changes, namely: the appearance of unusual high and low levels of annual floods, more and more intense storms, more severe droughts, forest fires, river erosion, cyclones, and tidal surges appear increasingly more dangerous. Traditional adaptation measures to the environmental conditions may be unsuitable in the context of climate change in the Mekong River Delta. This paper summarizes some of the new adaptation measures that scientists and policy planners have proposed for the area to cope with the negative impacts of climate change

Testing the impact of waste from anaerobic digestion (enriched with an organic component on the quality of agricultural land)

Waste from anaerobic digestion is considered as a mineral fertilizer and it is usually applied to agricultural land. The aim of our attempt was to enrich this waste from anaerobic digestion (digestate) with an organic component (in our case represented by haylage). For this purpose, we made different mixtures of digestate and haylage in different weight ratios. In the field trial, the effect of these mixtures on the soil, under standard agricultural conditions, was monitored. Selected accessible nutrients (P, K, Mg, Mn, Ca) and the amount of carbon and nitrogen in the soil were monitored. The results of the laboratory tests confirmed that the areas where the sowing and digestate mixtures were applied showed greater amounts of macro- and micronutrients in plant-accessible forms than the surface fertilized only with digestate or areas fertilized only with standard fertilizers

Contribution to the study of flocculation of digestate

The paper deals with the intensification of separating the solid phase of digestate using flocculants only. The separated solid phase should subsequently be used in agriculture for fertilising. Flocculants (polyacrylamides) are difficult to biodegrade. In this respect, they should not deteriorate the properties of the solid phase and the flocculant dose must be as low as possible. The research aimed to identify the optimal cationic flocculant and its application procedure which would enable a dosage that would be both economically and ecologically acceptable. We tested 21 cationic flocculants of different charge density and molecular weight and 1 mixture of two selected flocculants (Sokoflok 53 and Sokoflok 54) with the aim to discover the lowest possible dose of flocculating agent to achieve the effective aggregation of digestate particles. The lowest flocculant doses were obtained using the mixture of flocculants labelled Sokoflok 53 and Sokoflok 54 in 4:1 proportion, both of a low charge density and medium molecular weight, namely 14.54 g/kg of total solids for a digestate from the biogas plant Stonava and namely 11.80 g/kg of total solids for a digestate from the biogas plant Vrahovice. The findings also reveal that flocculation is most effective during two-stage flocculant dosing at different mixing time and intensity

Artificial recharge – measurement of soil infiltration in Rožnov pod Radhoštěm

The purpose of this study is to evaluate the potential for infiltration in a study area – Rožnov pod Radhoštěm, the Czech Republic. The results are important for the future design of an artificial recharge structure as a method to store water underground in times of water surplus. A total of six measurements of infiltration were made using a double ring infiltrometer on selected prospective sites for the future application of artificial recharge. The results of infiltration tests were analysed based on the Philip`s model. The steady soil infiltration rates ranged from 28 cm∙h-1 to 70.38 cm∙h-1and the cumulative soil infiltration ranged from 58 cm to 68 cm

Studium a výzkum postupů čištění anaerobní digesce

This paper focuses on increasing quantities of digestate, a final product of anaerobic digestion, in biogas stations being built as alternative sources of energy. The potential use of digestate is limited due to its rather specific physical properties. This paper presents current approaches to digestate and digestate management. The objective is to compare the properties of digestate and the products of its separation via centrifuging, i.e. the liquid phase known as digestate liquor, and the solid phase referred to as digestate fibre. Its focus is mainly laid on techniques for dewatering digestate in low-solid anaerobic processes only, which have been tested for the effectiveness of the basic physical and chemical methods including their combinations. The measured results show that the use of coagulants and flocculants for this purpose would be very problematic in practice with regard to their high consumption as well as the need to input other elements into the process.Předložený článek se zabývá problematikou narůstajícího množství digestátu jako konečného produktu anaerobní digesce v bioplynových stanicích, budovaných jako alternativní zdroje energie. Digestát má v současné době omezené využití, které je dáno jeho specifickými fyzikálními vlastnostmi, zejména extrémně problematickou separací jednotlivých složek, ale také chemickým a mikrobiologickým složením. Jeho vlastnosti jsou z největší části ovlivněny druhem zpracovávané biomasy. V úvodní části tato studie předkládá současné možnosti nakládání s digestátem. Předmětem experimentální části je popis odběru a analýzy vzorků digestátu včetně jeho zpracování v laboratorních podmínkách použitím odstředění a následné posouzení vlastností digestátu a produktů separace, tj. fugátu a separátu a dále testování koagulačních a flokulačních činidel pro účinnější separaci tuhé fáze z digestátu, resp. fugátu. Použití koagulantů a flokulantů pro tyto účely v praxi by bylo značně problematické s ohledem na jejich vysokou spotřebu a vnos dalších prvků do procesu

Sorpce vybraných těžkých kovů z odpadních vod pomocí netradičních sorpentů

The environment incl. water is exposed to heavy metals in the long term. Typically, industrial activities are the source of heavy metals penetrating the environment. The heavy metals are contained in many products and are a part of many waste substances. This paper deals with removal of copper, zinc and lead from waste waters by means of adsorption. Adsorbents are typically cheap substances, such as synthetic zeolite, bentonite or slovakite. Attention is paid to the adsorption rate and efficiency of removal of the heavy metals mentioned from the water.Ţivotní prostředí včetně vod je dlouhodobě zatěţováno těţkými kovy. Tyto se do prostředí dostávají hlavně činností průmyslu, jsou obsaţeny v celé řadě výrobků a tvoří součást mnoha odpadních látek. Tento článek se zabývá odstraňováním mědi, zinku a olova z odpadních vod pomocí adsorbce. Jako adsorbenty jsou vybrány látky, které jsou cenově dostupné, Jedná se o syntetický zeolit, bentonit a slovakit. Je sledována rychlost adsorpce a účinnost odstraňování uvedených těţkých kovů z vody

Water supply status in rural areas of the Mekong delta and development measures

Rural people in the Mekong Delta (MD) use surface water from rivers and canals for daily activities; and in areas far from the canals, people use rainwater for cooking and drinking. In certain areas, people use shallow layered groundwater and deep layered groundwater from drilled wells 80m – 100m deep. The quality of water used in daily activities of rural people is almost uncontrolled. Somewhere water supply systems are used, but they have been built over many periods, certain ones for over 50 years ago, thus having a lot of damage and many deposits, causing loss of pressure and huge loss of water. The issue of repairing, replacing and installing more water supply networks in urban areas is facing lots of financial, technical difficulties

Surface Integrity after Turning a Duplex Stainless Steel with Respect to Tool Geometry

This study deals with surface integrity expressed in terms of stress state as well as microstructure alterations after turning a duplex stainless steel. Residual stresses and the presence of strain-induced martensite are studied as functions of the rake angle. Residual stresses of surface and sub-surface layers were determined by the use of the X-ray diffraction and hole-drilling techniques. X-ray diffraction enables us to distinguish between residual stresses in each phase separately, which is not possible when the hole-drilling method is applied. Furthermore, alterations in the near surface region are also analysed by the use of the magnetic Barkhausen noise and metallographic observation

Tree-Ring Amplification of the Early Nineteenth-Century Summer Cooling in Central Europe

Les prokinéticines sont des facteurs angiogènic potentiels qui se liant aux récepteurs couplés aux protéines G (PKR1 et PKR2) pour initier leurs effets biologiques. Nous avons montré que le transfert transitoire du gène PKR1 après ligation de l’artère coronaire réduit la mortalité et préserve la fonction du ventricule gauche en favorisant la néovascularisation et protegé des cardiomyocytes. Nous avons montré que des souris transgéniques (TG) surexprimant PKR1 dans le coeur aucune anomalie spontanée dans les cardiomyocytes, mais on observe une augmentation de néovascularization. Cependant des souris TG surexprimant PKR2 dans le coeur ont montré de l'hypertrophie excentrique et la perméabilité vasculaire. Pour la première fois nous avons montré que la balance entre l'activation de la voie de signalisation de PKR1 et de PKR2 pouvait être très importante pour protéger les cardiomyocytes des lésions causées par l'ischémie et/ou d’induire la neovascularisation dans le coeur.Cardiovascular disease is first cause of mortality worldwide. Prokineticins are potent angiogenic factors that bind to two G protein-coupled receptors (PKR1 and PKR2) to initiate their biological effects. We showed that transient PKR1 gene transfer after coronary ligation reduces mortality and preserves left ventricular function by promoting neovascularization and protecting cardiomyocytes. Next we showed that transgenic (TG) mice overexpressing PKR1 in heart exhibit neovascularization without inducing any spontaneous pathology in cardiomyocytes. However TG mice overexpressing PKR2 in heart exhibit eccentric hypertrophy in cardiomyocyte and vascular leakage. As a conclusion, for the first time we have shown that the balance between the activation of PKR1 and PKR2 signaling could be very important to prevent cardiomyocytes from ischemic insult and/or to induce neovascularization in heart