Abstract. This work is aimed at providing a deep cleaning from nitrogen and phosphorus at the requirements level for a small capacity waste water treatment plants with active sludge. The wastewater treatment technology includes: mechanical screen, anaerobic reactor, anoxic reactor, two aerobic reactors with floating media, aerobic reactor, clarifier, bioreactor, purification, filter, filter of tertiary treatment with the sorbent, ultraviolet disinfection facility. The sludge treatment includes aerobic stabilizer and facility of mechanical dewatering. The developed technology ensures deep purification of household waste waters from nitrogen and phosphorus. The degree of purification in the ammonium-ion reaches of 99.5 %. Efficiency of total nitrogen removal (the sum of ammonium, nitrite and nitrate nitrogen) is 85 %. The efficiency of biological purification of phosphates is 97.8 percent that is achieved without the use of coagulant. Requirements are met in most cases.

Abstract. The article reveals the ways in which the reconstruction of clarifiers for wastewater treatment plant can be performed. One of the most common method is bioflocculation that means use of corresponding properties of excess activated sludge or biofilm, which both have in its composition so called extracellular biopolymers that determine the spatial structuring and bioflocculation of cell formations. Multiple researches showed that use of surplus sludge as bioflocculant provides increased efficiency of sedimentation in any waste water up to 85-90 % and reduce biochemical oxygen demand (BOD) in the clarified water by 40-50 %. The other method to be implemented for reconstruction of clarifying facilities is thin-layer modules to raise the efficiency of settling. Thin-layer modules can be used in a wide range of capacity of sewage works. The possibility of application depends on the structural size and condition of building structures, the amount of suspended solids and other parameters.

The article reveals various factors, which determine the maintenance of membrane bioreactors for treatment of domestic and industrial sewage. Contamination of membranes is a consequence of poor pretreatment, when membrane accumulates hair, scraps of rags and other fibrous materials on its' fibers and in the cavities of membrane blocks. Aeration conditions have a significant impact on the performance of the membranes, also in sufficient sludge liquor mixing leads to membrane clogging. Size of pores, material of membrane and washing peculiarities are the factors that can affect MBR operation. The costs for installation and operation of membrane modules is still the limiting factor of their wide application, however now the situation is changing. There are key differences between membrane and conventional treatment of wastewater revealed such as costs, required area and quality of treatment.

Abstract. The article touches upon the efficiency of small capacity wastewater treatment plant for industrial sewage. Current operation scheme fails to meet existing regulation requirements due to several drawbacks. The article describes a technology for wastewater treatment and the construction of bioreactor to implement the scheme above. The technology includes averaging tank with preliminary mechanical treatment and bioreactor with floating feed. This provides the efficiency of removal of organic compounds and nutrients: BOD -96%, nitrogen -99%, phosphorus -89%.

Introduction. The mixed liquor of nitrogen removal wastewater treatment plants is characterized by a high concentration of nitrates and dissolved oxygen at the inlet to the secondary settling tank. In the sludge layer of secondary sedimentation tanks, conditions of decreased oxygen content and uncontrolled denitrification processes take place. This leads to the floating up and removal of sludge with the effluent and secondary pollution of treated water. The purpose of this article is to study the parameters of activated sludge sedimentation in municipal wastewater treatment plants and their intensification by means of vacuuming. Materials and methods. The studies were carried out under laboratory conditions. Activated sludge vacuuming and sedimentation processes were simulated. Diagrams of the “sludge-water” phase reduction (Kinsh curves) were drawn. Mathematical and graphic processing of the results was carried out. Results. Biological treatment of municipal wastewater (aerotank — secondary settling tank) and methods of its intensification by influencing the activated sludge were considered in this article. Trends of activated sludge (at different concentrations of mixed liquor suspended solids) sedimentation were experimentally obtained for municipal wastewater treatment plants. The process of sludge vacuuming was researched, the process efficiency was determined as a function of the treatment time. Conclusions. Vacuuming allows removing gases from the fluid, which accelerates the process of sludge separation from the treated water and prevents it from floating to the surface. The treated sample is characterized by better sedimentation characteristics, density, coarseness and integrity of flakes. The optimal duration of mixed liquor vacuuming before sedimentation is 0.5 minutes; this accelerates the processes of subsequent sedimentation and reduces the removal of sludge with treated water. The results of laboratory tests can be applied to the design of the mixed liquor vacuuming unit before the secondary sedimentation tanks and its sludge separation.