Hydraulic operating features of filter cassettes as part of treatment facilities on highways

Surface runoff water (SRW) from highways is highly polluted and has negative impact on adjacent areas and water bodies. The article describes constructed wetlands (CW), including detention ponds and facilities for sorption post-treatment, one of the simplest methods to treat the SRW from highways. It is established that filter cassettes (FCs) based on gabion constructions (GC) and loaded with shungite rock (SR) are used as sorption post-treatment facility. One of the reasons for the unsatisfactory operation of such facilities on the St. Petersburg Ring Road (RR) has been analyzed. It is shown that the SR recommended for loading into FCs has a fractional composition of 2÷4 cm and thus provides a turbulent filtration mode of SRW passing through the facility. The impossibility of using SR with the optimal for sorption treatment fractional composition of 0.1÷0.3 cm within the existing GC is shown. It is also shown that the use of permeable for SRW containers – the filter cartridges (such as FOPS® filters) – is one of the simplest and most effective ways of using SR of optimal fractional composition and working with a large amount of sorption materials. The approach to the organization of complex multistage treatment of SRW is shown.