The objective of the study was to trace the variability of the hydrochemical conditions in three lakes of the West Pomeranian Voivodeship (Poland) – Starzyca, Maszewskie and Nowogardzkie in the annual cycle. The research was done in 2018–2019, and samples for analysis were collected 4 times a year. All analyses were performed applying standard methods. Such hydrochemical indices were determined as dissolved oxygen, chemical oxygen demand, content of orthophosphates, total phosphorus, nitrite, nitrate, ammonium, chlorophyll a and iron. The study showed that all lakes in the research cycle were characterised by a polymictic type of water mixing, and the trophic level, based on the adopted criteria, indicated advanced eutrophy, which may also be caused by anthropogenic pressure. Oxygen conditions characterised by deoxidation of the waters in the bottom layer in the spring and summer seasons, and clear oxygenation in the surface water layer (in Lake Maszewskie reaching even 188.5% in the spring) confirm the significant advancement of the eutrophication process. The supply of phosphorus and nitrogen in spring from pelagic waters in the waters of the examined lakes influences concentrations of chlorophyll a in the summer. The influence of “internal supply” (bottom waters and bottom sediments) on the amount of nutrients available for autotrophs is clearly visible in the analysed lakes – an increase in nitrogen and mineral phosphorus concentrations in relation to surface waters was observed in the bottom layer.

The work concerns an important in our times problem related to different areas as ecology, economy and proper use of energy resources: reduction of NOx by rebuming process. The main goal of the work was to develop the technology of NOx reduction during zone combustion of coal and mine gas with process optimal conditions determination in power boilers in aspect of environmental protection. In the work was presented: investigation of numeric model of zone combustion of coal and mine gas; aplied combustion research of the boiler OCG-64 produce on RAFAKO.

Primary or secondary sewage sludge in medium and large WWTP are most often processed by anaerobic digestion, as a method of conditioning, sludge quantity minimization and biogas production. With the aim to achieve the best results of sludge processing several modifications of technologies were suggested, investigated and introduced in the full technical scale. Various sludge pretreatment technologies before anaerobic treatment have been widely investigated and partially introduced. Obviously, there are always some limitations and some negative side effects. Selected aspects have been presented and discussed. The problem of nitrogen has been highlighted on the basis of the carried out investigations. The single and two step - mesophilic and thermophilic - anaerobic waste activated sludge digestion processes, preceded by preliminary hydrolysis were investigated. The aim of lab-scale experiments was pre-treatment of the sludge by means of low intensive alkaline and hydrodynamic disintegration. Depending on the pretreatment technologies and the digestion temperature large ammonia concentrations, up to 1800 mg NH4/dm3 have been measured. Return of the sludge liquor to the main sewage treatment line means additional nitrogen removal costs. Possible solutions are discussed.

The study of groundwaters was carried out in two different forest ecosystems of Słowiński National

Park: Vaccinio uliginosi-Betuletum pubescentis and Empetro nigri-Pinetum in the period of 2002-2005. Differences were found in the position of the groundwater table and in the concentrations of nitrogen and phosphorus

compounds in the investigated forest associations. In the Vaccinio uliginosi-Betuletum pubescentis association

the groundwater table was found on average at a depth of -73.3 cm, while in Empetro nigri-Pinetum at -90.2

cm. No statistically significant effect of precipitation on the position of the groundwater table was found in

this study. Statistical calculations (U Mann-Whitney test) for groundwaters in the analyzed forest associations

showed statistically significant differences in the dynamics of concentrations of total nitrogen (T-N), organic

nitrogen (Norg.), nitrate nitrogen (N-NO3

), total phosphorus (T-P), organic phosphorus (Porg.) and the level of

groundwaters.

The article presents the procedure for how to establish a mathematical model of nitrogen oxides formation based on the theory of dimensional analysis. The model is based on selected physical quantities (parameters) measurable during regular operation of a heat generation plant. The objective of using dimensional analysis to describe nitrogen oxides formation is to show that between operating parameters of the combustion equipment and the NOx formation there is a significant correlation.

The obtained results, which are further described in this article, have proved this fact. The obtained formula expressing nitrogen oxides formation, based on dimensional analysis, applies universally to any boiler fuelled by coal, gas or biomass. However, it is necessary to find C, m, n constants for the formula by experiment, individually for each type of boiler and used fuel. The experiment is based on on-line measurements of selected operational parameters for a given boiler, combusting a certain type of fuel with its actual moisture content and calorific value. The methodology, described in this article, helps to find relationships between the operational parameters and the formation of NOx emissions for a particular furnace. The developed mathematical model has been validated with boilers fuelled by black coal and biomass. Both the results obtained from direct measurements of NOx in both types of boilers, and the results obtained by calculation using equation based on the dimensional analysis, are in a very good accord. When burning coal, the variation between NOx expression from the model and the on-line measurements ranges between -12.23 % and + 9.92 %, and for burning biomass between -0.54 % and 0.48 %.

The intention of the authors is to inform the professional community about the suitability of the dimensional analysis to describe any phenomena for which there is currently no exact mathematical formulation based on differential equations or empirical formulas. Many other examples of dimensional analysis applications in practice may be found in the work of Čarnogurská and Příhoda (2011).

The paper presents research on using natural zcolitc modified for cleaning municipal sewage thoroughly. The research was carried out in laboratory scale in system composed of Sequencing Batch Reactors and filter bed with zeolitc modified with manganese ions. Synthetic sewage prepared on the basis of organic and mineral components was used for cleaning process. After biological treatment with activated sludge in the reactor, the sewage was directed to filtration column. Due to the fact that reactor was operating in cycles; the sewage was treated on the bed in portioned way and kept submerged. The research was carried out in a few stages: without regeneration of the bed, with periodic regeneration and cyclical after cach cycle of SBR reactor operation. Obtained results of nitrogen, phosphorous and carbon compounds removal were verified on real sewage. For that purpose biologically treated sewage was directed in a continuous way to a filtration column from secondary settling tank of sewage treatment plant, regenerating bed with different methods after exhausting its catalytic properties. Verification showed great effectiveness of used configuration for removal ammonia nitrogen, carbon and phosphorous compound from sewage. Decrease in electrical conductivity of sewage and a slight increase of nitrate nitrogen concentration was observed. The research showed great effectiveness of proposed filtration configuration for sewage treatment and a possibility of bed regeneration with keeping its work effectiveness.

The paper addresses the effect of a compost prepared from tobacco wastes with an admixture of bark and straw on the enzymatic activity and certain chemical properties of a grey-brown podzolic soil amended with that compost.

The study was conducted under the conditions of a pot experiment in which the soil material was collected from the surface horizon of the grey-brown podzolic soil. The effect of the application of the compost was compared with soil without such amendment. The test plant was maize cv. Kosmo 230. Fertilisation of the light soil with the compost studied caused changes in the enzymatic activity of the soil that were related both to the dose of the compost and to the kind of enzyme studied. With increase in the dose of the compost there was an increase in dehydrogenase activity (highest dose) and a significant decrease in the activity of acid phosphatase. Moreover, it was observed that tobacco compost was a significant source that enriched the light soil in organic matter, total nitrogen, and available forms of phosphorus, magnesium and potassium, which was evident in increased yields of maize grown as the test plant.

Significant correlations were also demonstrated between a majority of the biochemical and chemical parameters, which indicates that those parameters characterise well the biological properties of a grey-brown podzolic soil amended with tobacco compost.

Due to insufficient operation efficiency, the studied treatment plant has undergone modernization. The aim of this study was to assess whether this modernization improved quality of the STP effluent and water quality in the receiver. The research period of fifty months covered time before and after the modernization. Samples were collected in four sites – upstream and downstream of the STP and by the sewage discharge. Electrolytic conductivity, water temperature and pH were measured onsite. Chemical analyzes were based on ion chromatography and determined the concentration of NH₄⁺, NO₃^-, NO₂^-, PO₄^3-, TDS. Microbiological analysis comprised serial dilutions to assess the number of mesophilic and psychrophilic bacteria and membrane filtration to enumerate E. faecalis, total and fecal coliforms as well as total and fecal E. coli. Values of most analyzed parameters did not improve after the modernization, or improved for a very short period of time (NH₄⁺), while some of them even increased, such as PO₄^3-, total and thermotolerant coliforms and E. coli. The maximum value of thermotolerant E. coli reached nearly 7 million CFU/100 ml and was observed after modernization. Also at the sites situated downstream of the STP some of analyzed parameters increased. The conducted modernization did not improve the quality of treated sewage and even a further deterioration was observed. It could have been a result of rapidly growing number of tourists visiting the studied area, thus generating large amounts of sewage causing STP overload coupled with poor water and wastewater management. Significant percentage of unregistered tourists hinders proper assessment of the STP target efficiency.

The aim of this work was to compare nitrogen dioxide atmspheric pollution in some parts of Cracow and to indicate the area in which ambient air concentration of N02 may be the highest. The measurements of 24- hour N02 concentrarion were made by spectrophotometric method with passive sampling in 20 sites in the period of 2 years. The results were analysed by statistical methods, such as: analysis of variance and correlation. The 24-hour NO, concentration has significant spatial variation in the area of Cracow. The highest values were measured in the street canyons, the lowest in residential areas. The highest values of N02 concentration were observed during heating season. The results of passive method are comparable with the results of authomatic method and because of this both methods may be use together in monitoring networks.

In the paper, a numerical simulation of the co-combustion process of sewage sludge gasifi cation syngas in a hard coal-fi red boiler was done. Two different syngases (SS1 and SS2) were taken in consideration. Additional (reburning) fuel was injected into the combustion chamber, which was modeled as a plug fl ow reactor (PFR). The molar fl ow rates ratio of reburning fuel is assumed to be 5.0%, 7.5%, 10.0%, 12.5% and 15.0% of the whole exhaust. The simulations were conducted for constant pressure equal to 1atm for temperatures range from 600 to 1400 K. It was assumed that a fl ue gases which enters the reburning zone contains 300 ppm of NO and that during combustion only NO is formed without other NOx. Results show that that gas from sewage sludge gasifi cation gives reburning effi ciency of up to 90%. Calculation shows also an optimum value of temperature reburning for gas from sewage sludge gasifi cation which is equal to 1200 K. The type of the sewage sludge has no strong infl uence on the NO reduction.

There are certain well-known methods of diminishing concentrations of nitrogen compounds, but they are ineffective in case of nitrogen-rich wastewater with a low content of biodegradable carbon. Partial nitritation followed by anaerobic ammonium oxidation (Anammox) process appear to be an excellent alternative for traditional nitrification and denitrification. This paper presents the feasibility of successful start-up of Anammox process in a laboratory-scale membrane bioreactor (MBR). It was shown that the combination of membrane technology and Anammox process allowed to create a new highly efficient and compact system for nitrogen removal. It was possible to achieve average nitrogen removal efficiency equal to 76.7 ± 8.3%. It was shown that the start-up period of 6 months was needed to obtain high nitrogen removal efficiency. The applied biochemical model of the Anammox process was based on the state-of-the-art Activated Sludge Model No.1 (ASM 1) which was modified for accounting activity of autotrophs (nitrite-oxidising bacteria and nitrateoxidising bacteria) and anammox bacteria. In order to increase the predictive power of the simulation selected parameters of the model were adjusted during model calibration. Readjustment of the model parameters based on the critically evaluated data of the reactor resulted in a satisfactory match between the model predictions and the actual observations.

Organic carbon, nitrogen, and phosphorus in the soils of the High Arctic play an important role in the context of global warming, biodiversity, and richness of tundra vegetation. The main aim of the present study was to determine the content and spatial distribution of soil organic carbon (SOC), total nitrogen (N tot ), and total phosphorus (P tot ) in the surface horizons of Arctic soils obtained from the lower part of the Fuglebekken catchment in Spitsbergen as an example of a small non−glaciated catchment representing uplifted marine terraces of the Svalbard Archipelago. The obtained results indicate that surface soil horizons in the Fuglebekken catchment show considerable differences in content of SOC, N tot , and P tot . This mosaic is related to high variability of soil type, local hydrology, vegetation (type and quantity), and especially location of seabird nesting colony. The highest content of SOC, N tot , and P tot occurs in soil surface horizons obtained from sites fertilized by seabird guano and located along streams flowing from the direction of the seabird colony. The content of SOC, N tot , and P tot is strongly negatively correlated with distance from seabird colony indicating a strong influence of the birds on the fertility of the studied soils and indirectly on the accumulation of soil organic matter. The lowest content of SOC, N tot , and P tot occurs in soil surface horizons obtained from the lateral moraine of the Hansbreen glacier and from sites in the close vicinity of the lateral moraine. The content of N tot ,P tot , and SOC in soil surface horizons are strongly and positively correlated with one another, i.e. the higher the content of nutrients, the higher the content of SOC. The spatial distribution of SOC, N tot , and P tot in soils of the Hornsund area in SW Spitsbergen reflects the combined effects of severe climate conditions and periglacial processes. Seabirds play a crucial role in nutrient enrichment in these weakly developed soils.

The article presents the results of research aimed at determining the catchment areas that pose a risk of nitrogen pollution of the waters of the Mała Panew river. The research was carried out in 13 permanent monitoring points located on the Mała Panew. The location of the points ensured the representativeness of the water quality results for parts of the catchment area with a homogeneous type of land use. Concentrations of nitrate-nitrogen (NO3-N) and total nitrogen (TN) were determined in the samples taken. The content of (NO3-N) in the third quarter of the year and its relation to the value obtained for the first year quarter may be an indicator of the impact of agricultural activities on the quality of water in streams. In the case of agricultural catchments, the lowest concentrations of NO3-N and TN occur in the third quarter of the year and are significantly lower than in the first quarter of the year. The demonstrated seasonal variability of nitrate nitrogen concentrations in agriculturally used areas may be used to determine the type of pressure not allowing to achieve good water status in the surface water body. It was shown that the highest unit increments occurred in areas with a high proportion of forest.

ln laboratory electrically heated entrained flow reactor with quasi one-dimensional laminar flow the influence of fuel properties on the nitrogen oxide emission for 23 coals of various rank from brown coal, bituminous coal to anthracites has been examined. For one brown coal type twofold increase of nitrogen content resulted in NO, emissions increase of about 30%. Increasing rank from brown coal to bituminous coal increases NO emissions and next a fall in the anthracites range. With nitrogen content increase NO - emission grows a~d the ratio of fuel nitrogen conversion to nitrogen oxide decreases. Experiments results and their statistical analysis were used to determine relationships describing NO, emissions and conversion ratio of fuel nitrogen to nitrogen oxide as functions of two variables. describing coal properties, i.e. nitrogen content and fuel ratio (fixed carbon to volatile matter ratio).

Studied was a small (4.6 ha) meromictic lake situated in a deep land hollow surrounded by a highinclination slope. The lake was made shallower two times (from 20 to 18 m) by collapsed shores. It is fed by underground waters and has relatively constant outflow. Limited water dynamics reduced the epilimnion thickness (from 4 to 2 m) and influenced the monimolimnion setting below 13 m depth with a characteristic small (0.2°C) temperature increase in the vertical profile and a permanent deoxygenation of the water below 7-11 m depth. The relationship between the organic matter parameters BOD; and COD-Mn before the shore collapse revealed the dominance of matter produced in the reservoir. In the final period the situation was opposite. In the monimolimnion allochthonous matter accumulated which due to anaerobic decomposition generated large amounts of ammonium. Observed in the same water layer was also a decrease of the conductivity.

Results of testing air quality in the vicinity of Gliwice transport routes arc presented in the paper. Assessment of air contamination with nitrogen dioxide from motor transport, for typical conditions dominating in big cities of high transit movement without any ring roads was the studies objective. Presented results will be used in the future to determine the impact of opening the ring road on air quality in the city. In the studies, the passive method of sampling, with further application of spectrophotometric technique to determine nitrogen dioxide concentration, was used. Average annual nitrogen dioxide concentrations were based on average daily concentrations measured from July 2004 to June 2005 at 16 measuring points. As they meet conditions for random distribution of measuring days and cover the measuring time, they were treated as average concentrations of nitrogen dioxide in a calendar year and were compared with a permissible concentration to make an assessment of air quality..

According to the Nitrate Directive it is necessary to established a protective belt (ecotones) around lakes. Inside these belts, it is forbidden to use fertilize for agricultural purposes. It is believed that it is the most imported measure to protect water quality in the lake. The analysis were conducted to estimate the sources of nitrogen entering the waters of the lake. Some analysis were conducted to estimate the sources of nitrogen entering waters of the lake. It was proved that the biggest load (more than 80%) of contamination is entering the lake with water flowing in streams and ditches. Only 10% of the chemicals are entering the lake with the groundwater filtrating to the lake. It is very important to use a proper methods of agriculture with proper methods of fertilization in the whole area of river basin flowing to the lakes.

Based on FAO data, the paper presents trends in nitrogen (N) input and output in Poland. As N input ( N _inp), nitrogen from mineral fertilisers, manure application, biological fixation, and deposition was included. The N outputs ( N _out) include the N contained in crop harvest (main products and by-products). The trend analyses were carried out for the period before (1961–1989) and after (1990–2018) the changes in the political and economic systems. Additionally, trends in the nitrogen use efficiency ( NUE) and nitrogen surpluses ( N _S) are presented for these periods. In both compared periods, the mean values of N budget indicators in Poland were (kg N∙ha ^–1 UAA): N _inp 120 and 125, N _out 61 and 84, N _S 60 and 41 and NUE 53 and 67%, respectively. The estimated Y _max, which represents the N _out value reached at saturating N fertilisation, reached the values of 127 and 263 kg N∙ha ^–1 UAA in these periods. The difference in these values suggests a significant impact of agronomy improvement on N _out in the recent period. The trends of nitrogen within 16 regions in period 2002–2019, based on national data, resulted in a significant variation in N indicators. The values found were in the following ranges (kg N∙ha ^–1 UAA): N _inp 78–167; N _out 62–99; N _S 15–83 and Y _max 139–317. The NUE ranged from 50–81%. The obtained results indicate that in Poland and its regions there is still a need to improve of the nitrogen efficiency.