Carbon dioxide sequestration and its long-term immobilisation in biomass is recently an extremely significant problem. Its greatest reserves occur in forests growing all over the globe. A human being, through their conscious action, ought to affect, among other things, the amount of carbon dioxide discharged into the atmosphere and its rational management. Here, quite a good solution seems to be the immobilisation of CO2 in biomass of plants, and in particular, in trees, characterised by their longevity, which are used most frequently for that purpose.

Such carbon dioxide management allows for its several-decade immobilisation within living plants, while a further processing of wood mass allows for halting it for consecutive years in products manufactured. Additionally, in the case when within a selected land planted with trees the effluent irrigation is being carried out, simultaneous sewage treatment is also an advantage. By using plants characterised by intense increment in biomass within facilities, also biogens occurring in effluents may be effectively removed.

In the analysed case, sewage treatment consisted in entry of household sewage into a prepared surface which was previously subject to mechanical purification. All the sections were sown with grass mixture and plantings of poplar were used. Observations were made during the period of 17 years. The effluents entered onto the surface of the sections and the effluents outflowing from the facility were subject to a physicochemical analysis in order to determine the operational efficiency of a plant - soil treatment system. Also, a threefold inventory of a forest stand was made in order to determine the increment in trees.

The last inventory was made in 2014. Based on dendrological characteristics, the average volume of wood mass obtained from the land irrigated with effluents was assessed.

A rational management of effluents on the grounds without any central drainage allows for a parallel solution to some problems. First of all, purification of effluents in a natural environment by closing the matter cycle, and additionally contributing to the limitation of carbon dioxide emission by its halting in plant biomass.

TCE artificially contaminated soil was cleaned under anaerobic, reductive conditions. A laboratory scale treatability studies were carried out to determine optimal physico-chcmical and microbiological parameters for biorcmcdiation process. Upon treatability studies results a sewage sludge mixture was chosen as a microorganism's source. The chlorinated solvents contaminated soil bioreactor (CSCS bioreactor) was designed and built. It consists of a 6 m3 reactor vessel, a gas recirculation system, a leachate recirculation system and a data acquisition system. The bioreactor vessel was designed as a continuous gas flow packed bed reactor. During 210 days 4 Mg of soil containing approximately 350 mg TCE/kg of soil has been completely remediated under anaerobic conditions. The obtained results indicate that the stepwise dechlorination of TCE to ETH occurs in the bioreactor. Increasing amounts of chloride in the leachate were correlated with dechlorination.