The aim of this work is to study the immobilization ability of new composite materials based on polyethylene (PE) and polysaccharides (PS) in relation to the biocenosis of activated sludge (AS). The objects of the study were selected composite materials of the following composition: PE : pure microcellulose (MCc), PE : waste microcellulose (MCw), PE : starch (ST), at a ratio of components PE : PS = 70:30 wt.%. The objectives of the study were to determine the main morphological parameters of new composites (porosity, roughness, density), assessment of hydrochemical and hydrobiological state of AS (silt index, mass concentration of silt, species composition) until it locks into composites, assessment of the immobilization ability of the studied materials by biomass weight gain, monitoring of the state of AS after fixing. The tests found that the composite of structure of PE : MCc of has a density of 410 kg/m3 and a porosity of 60%, the roughness of 3.5; the composite of structure of PE : MCw has a density of 590 kg/m3 and a porosity of 40%, roughness of 2.0, composite of structure of PE : ST has a density of 640 kg/m3 and a porosity of 50%, the roughness of 2.5; wherein the reference sample - PE - has the parameters: density 860 kg/m3 and a porosity of 0%, roughness 0. To determine the immobilization capacity of the new composite materials, a laboratory experimental immobilizer was used, which is a container filled with 70% of the useful volume of the active sludge suspension and 30% of the floating loading samples. Immobilization was carried out under aeration conditions during 2, 4, 8, 12, 24, 48, 72 hours. As a result of tests it is established that the sample of structure of PE : MCc for 72 hours of immobilization showed a gain of biomass of the order of 12%, the sample of structure of PE : MCw - 5%, the sample of structure of PE : ST – 7%, PE – 3%. The condition of the organisms AS after fixing was evaluated by washings with immobilized samples, as a result of microscopy of washouts, the presence of living representatives of the biocenosis of AS in all samples was established, but they differ in number: for the sample of structure of PE : MCc - numerous, PE : MCw, PE : ST - average number, PE - small number. Further studies on the modification of the synthetic polyolefin matrix by functional fillers, including those from a number of polysaccharides, are of interest, allowing to increase the affinity of the carrier material with the extracellular matrix of activated sludge.

The article presents the results of a study of the rheological behavior of binary composites based on serial polyethylene grade LDPE 15803-020 with different content of microcellulose grade Filtracell, in a wide range of temperatures and shear rates during deformation through a capillary diameter of 1 mm and a length of 5 and 30 mm. Stable flow regime is manifested in the temperature range from 160 to 200°C for composites containing microcellulose in an amount of 30 wt.%, and its partial replacement with spent microcellulose (waste production of vegetable oils) can reduce the effective viscosity to 25%, but the upper limit of the temperature range is limited to the exudation of impurities (190°C). The Bagley correction is carried out, the coefficients of the equations describing the dependences of the true shear stress, regardless of the capillary length, are calculated.

In this paper, a composite material based on LDPE filled with 30 vol.% wood microcellulose (MC), in order to assess the possibility of its use as a biomass carrier treatment facilities.The material was obtained in industrial conditions by means of a twin-screw extruder with a leaf head, then samples of a composite biomass carrier in the form of discs with a diameter of 4 cm and a thickness of 1.5 mm were obtained from the sheet by means of a cutting press.Investigated the microstructure and morphological parameters of the composite, it was found that the porosity is about 58%, the surface roughness is 3.5 units of density about 450 kg/cubic m. the basic technological parameters of the melt of the composite by the method of capillary viscometry, the dependences of the shear stress and the melt viscosity of the test material in the velocity range processing, it was found that the composite refers to satisfactory recyclable thermoplastics. Bagley correction was performed. The thermomechanical stability of the material was investigated, the critical temperature of processing-200 °C. the operational properties of the material were Investigated: the tensile strength was 1.6 MPa, the elongation at break-12%, water absorption for 24 hours of soaking-31.2%. The dry biomass residue of activated sludge for 10 days of its immobilization on a composite biomass carrier amounted to 5.54%, which exceeds by 2.4 times the biomass growth on the traditionally used material-pure polyethylene. The material has a relative chemical resistance, does not lose its performance over a long period of operation. In particular, the loss of tensile strength after 5-fold freezing, soaking in 0.01 n solutions of sulfuric acid, acetic acid and sodium hydroxide (for 6 months), exposure to UV solar radiation (for 12 months), soaking in water (for 12 months) did not exceed 10-12%. Thus, the composite composition of LDPE: MC (70: 30 vol.% ) can be recommended for use in biological treatment plants as a highly efficient carrier material-biomass.