The author critically discusses the legislation relating to ports and landing areas of 20 December I 996. He writes that it permits the existence and functioning in one port ofmany "managing" entities. Law relating to water is the third piece of legislation - along with those pieces relating to ports and to maritime administration - regulating the status of seaports, understood as "water and ground". The fourth piece of legislation regulating this status is that relating to trade in real estate. The author devotes a great deal of attention to payments made to ports. He also writes of payments for port services.

The aim of this study was to determine the impact of the temperature of wastewater in a biological reactor with activated sludge and the BOD₅/N-NH₄ ratio in the influent to the treatment plant on nitrification efficiency and the concentration of ammonium nitrogen in treated wastewater. Tests were carried out in a household wastewater treatment plant which collects and treats sewage from a school building and a teacher’s house. During the 3-year study, large fluctuations in the sewage temperature in bioreactor were noted which was closely related to the ambient temperature. There were also large fluctuations in the concentration of organic matter and the concentration of ammonium nitrogen in inflowing sewage. The influence of wastewater temperature in the bioreactor and the BOD₅/N-NH₄ ratio on the concentration of ammonium nitrogen in treated wastewater was determined using Pearson’s linear correlation. A statistical analysis showed that a 1°C decrease in the temperature of wastewater in the bioreactor increased the concentration of ammonium nitrogen in treated wastewater by 2.64 mgN-NH₄·L^-1. Moreover, it was found that nitrification depended on the ratio of BOD₅ to the concentration of ammonium nitrogen in wastewater flowing into the bioreactor. An increase in the BOD₅/N-NH₄ ratio by 1 value led to a 5.41 mgN-NH₄·L^-1 decrease in the concentration of ammonium nitrogen.

Main topic of the paper is a problem of designing the input-output decoupling controllers for nonholonomic mobile manipulators. We propose a selection of output functions in much more general form than in [1,2]. Regularity conditions guaranteeing the existence of the input-output decoupling control law are presented. Theoretical considerations are illustrated with simulations for mobile manipulator consisting of RTR robotic arm mounted atop of a unicycle which moves in 3D-space.