The problem of outlying observations is very well-known in the surveying data processing. Outliers might have several sources, different magnitudes, and shares within the whole observation set. It means that it is not possible to propose one universal method to deal with such observations. There are two general approaches in such a context: data cleaning or robust estimation. For example, the robust M-estimation has found many practical applications. However, there are other options, such as R-estimation or the absolute M _split estimation. The latter method was created to be less sensitive to outliers than the squared M _split estimation (the basic variant of Msplit estimation). From the theoretical point of view, the absolute M _split estimation cannot be classified as a robust method; however, it was proved that it could be used in such a context under certain conditions. The paper presents the primary comparison between that method and a conventional robust M-estimation. The results show that the absolute M _split estimation predominates over the classical methods, especially when the percentage of outliers is high. Thus, that method might be used to process LiDAR data, including mismeasured points. Processing synthetic data from terrestrial laser scanning or airborne laser scanning confirms that the absolute M _{split / estimation can deal with outliers sufficiently.}

Humic substances (HS) are hydrophobic parts of dissolved organic matter, which are hard to degrade using biological processes. When exposed to disinfection processes, the HS present in wastewater could lead to the formation of disinfection by-products (DBPs), which are harmful and dangerous to health. Thus, a chemical coagulation process is commonly used for HS removal. This work used a cylindrical galvanic cell (CGC) with an iron anode and a copper cathode, where the dissolution of the anode served as an alternative source of metal ions for HS coagulation. The galvanic cell current for CGC stabilized at around 0.6 mA, and the voltage fluctuated, ca. 0.5 V for all solutions. The peaks observed on cyclic voltammograms could be associated only with oxidation and dissolution of iron; no other process was identified. After the process, the structures and molecular composition of the anode surface suggest the loss of Fe mass and the formation of iron oxides due to corrosion. The initial pH of the tested solution influenced the total Fe concentration in the solution as well as colour and turbidity. The quantitative removal of HS by electrolysis and membrane filtration processes at initial pHi = 6.0 yielded 72% and 90%, respectively, after 6 and 10 min. The mechanism of sorption on the flocs of hydroxides as a primary factor in HA removal was suggested.