The effect of an acidic environment during the hydrothermal carbonization of sewage sludge on solid and liquid products: The fate of heavy metals, phosphorus and other compounds.

The pH of sewage sludge is a crucial factor during the hydrothermal carbonization process that influences the characteristics of the resulting products and migration of certain compounds from the solid to liquid phase. Accordingly, this work is focused on examining the pH impact during the HTC process, in particular, pH equals 2, 3, 4, 5 and 6 on the individual hydrothermally carbonized products generated at 200 °C and 2 h residence time. For this reason, the chemical and physical indicators describing the post-processing liquid and hydrochar were determined. For instance, it was observed that the phosphorus content detected in the liquid, derived at pH2, rose significantly by 80%. Furthermore, decreasing the pH of sewage sludge had a significant impact on the ash content and the calorific value of the hydrochar. Additionally, changes in the specific surface area of hydrochar were noticed: pH = 5 and pH = 6 showed an increase of 20-30%, while for lower pH values a decrease of c.a. 26% was achieved. The distribution of heavy metals between the obtained fractions in the HTC process (solid and liquid) indicated that 92 to almost 100% of the tested heavy metals were transferred to the hydrochar. A significant effect of pH on the distribution between these fractions was observed only for Zn and Ni. For instance, for pH = 2, Zn and Ni in post-processing liquid were 34% and 29%, respectively. In addition, the sequential extraction of heavy metals from hydrochar was also performed in order to identify mobile and non-mobile phases. It was noticed that the acidic environment favours a higher amount of mobile heavy metals in hydrochar. The largest effect was observed for Cd, Pb, Cr and Cu, for which, at pH = 2, their respective amounts in the mobile fraction were 2.7; 3.6; 1.8; 6.2 times higher, compared to the hydrochar without pH correction.

The influence of selected anthropometric parameters on psychomotor abilities among professional Rugby Union players.

BACKGROUND: One of the most popular varieties of rugby is Rugby Union, in which a team consists of 15 players. Rugby Union is a full-contact sport, and players must demonstrate strength, endurance, speed and agility. During the match, players participate in multiple physical collisions and tackles, short-duration and high-intensity sprinting efforts. In addition, one of the elements affecting the effectiveness of the player's game can be the reaction time of the rugby player to the visual stimulus and the ability to read the game and react to the situations on the pitch. The level of psychomotor abilities of a person or a player practising sports can be influenced by various factors, including age, body height, body weight, type of sport practised or level of training. The study aimed to analyse the psychomotor abilities of professional rugby union players, investigate the relationship between the selected anthropometric characteristics and psychomotor abilities, and compare obtained results with the control group. METHODS: The study covered 22 players of the Polish National Team (age: 29.3 ± 5.4) and 27 students in the control group (age: 24.3 ± 3.9). The tests were carried out using the Test2Drive computer system of tests. For psychomotor abilities analysis, four tests were used: Simple Reaction Test, Choice Reaction Time Test, Hand-Eye Coordination Test and Spatial Orientation Test. The statistical analysis compares groups using basic statistical measures, and statistically significant differences between groups were checked. In addition, multiple linear regression was used. RESULTS: The analysis showed statistically significant differences between the groups in the simple reaction time test and the movement time for the test assessing reaction time with choice and eye-hand coordination. Multiple regression analysis conducted for both groups showed a statistically significant influence of some anthropometric parameters on the examined psychomotor abilities. The calculated multiple regression models had a high fit. CONCLUSIONS: The analysis showed that professional Rugby Union players have shorter movement time than the control group. For reaction time, statistically significant differences were observed only for simple reaction time. Moreover, linear regression analysis showed that body height and weight affect the selected psychomotor abilities.

The effect of an acid catalyst on the hydrothermal carbonization of sewage sludge.

This research is focused on the addition of a catalyst, sulphuric acid (VI), to sewage sludge, and its effect on solid and liquid products resulting from the hydrothermal carbonization process. Consequently, for hydrochars, proximate and ultimate analyses, higher heating value and specific surface area were determined. Additionally, Fourier-transform infrared spectrophotometric and thermogravimetric analyses were conducted. The heavy metal contents in the ash composition of hydrochars were identified by X-ray fluorescence spectrometry. It was confirmed that the catalyst addition changed the structure as well as the physical and chemical properties of hydrochars and their ashes. Regarding post-processing water, both pH value and conductivity were determined and the element composition, including heavy metals, was conducted by the inductively coupled plasma optical emission and mass spectrometry analyses. It was found that the addition of the catalyst caused a decrease in heavy metal contents and an increase of phosphorus compound in filtrates.

Life cycle assessment of the hydrothermal carbonization process applied to the wet fraction mechanically separated from municipal mixed waste.

The under-sieve fraction (USF), obtained as one of the output streams from the mechanical pretreatment of mixed municipal solid waste, is usually aerobically biologically stabilized before being landfilled. For its characteristics (i.e., moisture and organic content), the USF can be alternatively processed by hydrothermal carbonization (HTC), producing hydrochar to be used for energy production. Based on previous results obtained from laboratory HTC tests of the USF, this work is aimed at evaluating the sustainability of the proposed process from an environmental point of view by applying the Life Cycle Assessment. Various combinations of process parameters (temperature, time, and dry solid-to-water ratios) and two different utilization pathways for hydrochar (the whole amount produced in external lignite power plants or part of it used internally) are compared. The results indicate that environmental performances are mainly connected with process energy consumption: in general, the cases operating at the lowest dilution ratio and the highest temperature provide improved environmental indicators. Co-combusting all the produced hydrochar in external power plants provides better environmental performances than feeding a portion of it to the HTC itself: the avoided effects by displacing lignite are higher than the additional burdens from natural gas use. Then, alternative process water treatments are compared, showing that the burdens added by the process water treatments do not offset the benefits generated by the main HTC process for the major part of the considered environmental indicators. Finally, the proposed process indicates better environmental performances when compared to the conventional method of treating the USF, based on aerobic biostabilization and landfilling.

The treatment of post-processing liquid from the hydrothermal carbonization of sewage sludge.

The liquid phase, being a major product of the hydrothermal carbonization of sewage sludge, is highly problematic due to numerous toxic compounds that make it impossible to dispose of without adequate purification. Therefore, this study is focused on the two groups of selected advanced methods of post-processing water derived from the hydrothermal carbonization process of sewage sludge. The first group included membrane processes, namely ultrafiltration, nanofiltration and double nanofiltration. The second included coagulation, ultrasonication and chlorination. Chemical and physical indicators were determined to confirm the validity of these treatment methods. The highest reduction values were found for double nanofiltration, which showed a spectacular decrease in the Chemical Oxygen Demand by 84.9 %, specific conductivity by 71.3 %, nitrate nitrogen by 92.4 %, phosphate phosphorus by 97.1 %, total organic carbon by 83.3 %, total carbon by 83.6 %, and inorganic carbon by 88.5 %, as compared to the liquid phase after hydrothermal carbonization. In the second group, for the largest number of parameters, the greatest reduction was achieved when 10 cm3/L of iron coagulant was added to the permeate from ultrafiltration. Additionally, COD decreased by 41 %, P-PO43- content by 78 %, phenol content by 34 %, TOC content by 97 %, TC content by 95 % and IC content by 40 %.

Characteristics of the level of psychomotor abilities of female handball players.

BACKGROUND: Handball is a high-intensity game, during which players run, change directions with or without the ball, interact with the opponent and make different decisions in both offensive and defensive actions. Players' performance may depend on a number of factors, including explosive force, power, speed and agility. Players' results may be significantly influenced by their, psychomotor abilities. This article presents an analysis of selected psychomotor abilities of female handball players at different level of competition. METHODS: Test2Drive computer tests were used. The following four tests were used to measure psychomotor abilities: the Simple Reaction Time Test (SIRT), the Choice Reaction Time Test (CHORT), the Hand-Eye Coordination Test and the Spatial Anticipation Test (SPANT). The study covered a group of 118 female handball players (average age 19.6 ± 3.16), playing in the PGNiG Polish Women's Superliga, the Polish 1st Handball League and 2nd the Polish 2nd Handball League, in the playing positions: goalkeepers, centre players, pivot players and wing players. The study also included analyses of the players' body composition and aerobic capacity through the use of the multistage 20-m shuttle run test. In addition, the players' psychomotor abilities were analysed depending on the level of competition and playing position. RESULTS: The analysis of the reaction time and movement time showed statistically significant differences between the results obtained by the female handball players on different levels of competition. Moreover the female players from the Polish Women's Superliga exhibited the fastest reaction times according to the SIRT, the CHORT and the SPANT. Additionally, on the basis of the linear Pearson correlation coefficient, a statistically significant relationship was determined between the players' psychomotor abilities (movement time in the SIRT, the CHORT and the SPANT) and elements of their body composition or aerobic capacity. CONCLUSIONS: The analysis showed that the higher the level of competition (leagues), the shorter the female handball players' reaction times. The study also revealed that the players' body mass index and percentage of fat content reassociated with movement times, while their aerobic capacity (measured in the multistage 20-m shuttle run test) had a significant influence on their reaction times. This study shows that reaction time it's one of ability which should be consider to develop in training of female handball players.

Psychomotor abilities of candidates for Polish Special Forces.

Combat tasks involving special units often put a mental and physical strain on the soldiers. During the military operation, soldiers may struggle with multiple difficulties such as extreme physical effort, sleep deprivation, weather conditions, limited access to food and stress. These circumstances require a high level of cognitive ability (including psychomotor abilities) to overcome the physiological stress response and to be able to quickly and efficiently make decisions under stressful situations, especially in combat. The aim of the study was to assess the level of the psychomotor abilities of candidates for the Polish Special Forces. The study comprised 48 candidates for the Polish Special Forces (age: [Formula: see text]), 40 athletes (age: [Formula: see text]) and 40 non-athletes (age: 24). The study was performed using Test2Drive software. Four computer-based tests were used to assess the following psychomotor abilities: simple reaction time, choice reaction time, hand-eye coordination and two-dimensional visuomotor coordination/spatial orientation test (SPANT). The analysis demonstrated statistically significant differences in reaction time and motor time between the study groups. The shortest reaction time in each test was observed in athletes, while the shortest motor time was observed in soldiers. All the psychomotor tests, except for the number of correct answers in SPANT, demonstrated statistically significant differences between the studied groups. It was also found that military training had a positive effect on the motor time in every psychomotor test. As regards the reaction time, it was observed that the athletes were characterised with better reaction times than the special forces candidates. The study has confirmed that military training and sports training have a positive effect on the level of psychomotor abilities, especially motor time.

Characteristics of Cognitive Abilities among Youths Practicing Football.

The aim of the study was to assess selected cognitive abilities depending on age, anthropometric parametres, physical fitness and technical skills in the group of young players training football. The study covered a group of 258 young players practicing football (age: 12.1± 2.03), who were divided into 5 age categories (8-9 years old, 10-11 years old, 12-13 years old, 14-15 years old, 16-17 years old). Selected cognitive abilities include: simple reaction time (SIRT), complex reaction time (CHORT), hand-eye coordination (HECOR) and spatial orientation (SPANT). Studies were performed using Test2Drive computer tests. In addition, the level of physical fitness was measured using: The standing long jump, 30 m sprint, 20 m shuttle run test (without and with the ball) and slalom (without and with the ball). The analysis showed a statistically significant relationship between age and cognitive abilities. There was also a statistically significant correlation between fitness tests and reaction time in individual cognitive tests. There were no statistically significant relationships between technical skills and cognitive abilities. The study confirms that age and physical fitness affect the level of cognitive abilities.

Psychomotor Abilities of Professional Handball Players.

The main purpose of the paper was to evaluate selected psychomotor abilities of handball players depending on the competition class (league), position on the court, training seniority and the dominant hand. The study covered a group of 40 handball players (age: 24.02 ± 3.99), while 50 non-training men (age: 22.90 ± 1.13) formed the control group. Studies were performed using Test2Drive computer tests. The following four tests were used for measuring psychomotor fitness: simple reaction time test, choice reaction time test, hand-eye coordination test and spatial anticipation test. An analysis revealed that handball players had better reaction times and movement times than the control group. The league, position on the court, training seniority and the dominant upper limb were analysed for their impact on the reaction time and movement time in handball players. An analysis of psychomotor abilities of handball players with regard to the league revealed that in the majority of tests the Superliga players had a shorter reaction time than players in lower leagues.