Abstract
The biological wastewater treatment technologies in anoxic and aerobic bioreactors with recycle of sludge mixture are used for the effective removal of organic compounds from wastewater. The change rate of sludge mixture recirculation between bioreactors leads to a change and redistribution of concentrations of organic compounds in sludge mixture in bioreactors and change hydrodynamic regimes in bioreactors. Determination of the coefficient of internal recirculation of sludge mixture between bioreactors is important for the choice of technological parameters of biological treatment (wastewater treatment duration in anoxic and aerobic bioreactors, flow capacity of recirculation pumps). Determination of the coefficient of internal recirculation of sludge mixture requires integrated consideration of hydrodynamic parameter (flow rate), kinetic parameter (rate of oxidation of organic compounds) and physical-chemical parameter of wastewater (concentration of organic compounds). The conducted numerical experiment from the proposed mathematical equations allowed to obtain analytical dependences of the coefficient of internal recirculation sludge mixture between bioreactors on the concentration of organic compounds in wastewater, the duration of wastewater treatment in bioreactors.
Highlights
The biological oxygen demands (BOD5) in municipal wastewater usually are 100300 mgО2/l
Decrease of concentration of organic compounds from 300 mgBOD/l to 15 mgBOD/l with treatment duration of wastewater in anoxic bioreactor 0.5 hours and aerobic bioreactor 3 hours is provided with a coefficient of internal recirculation of sludge mixture of 180% (Fig. 2)
For decrease of concentration of organic compounds from 300 mgBOD/l to 15 mgBOD/l with wastewater treatment duration in anoxic bioreactor 0.5 hours and aerobic bioreactor 2 hours is provided with a coefficient of internal recirculation of sludge mixture of 380% (Fig. 3)
Summary
The biological oxygen demands (BOD5) in municipal wastewater usually are 100300 mgО2/l. The municipal wastewater usually contains suspended solids 147.3-468.2 mg/l, phosphor compounds 0.2-15.8 mg/l, nitrogen compounds 13.2-63.7 mg/l, synthetic detergents 8-25 mg/l [1, 2]. The anoxic and aerobic biological treatment technology is mainly used for the effective removal of organic compounds and nutrients from municipal wastewater [6]. The assessment oxidation velocity (kinetic parameters) of organic compounds in aerobic and anoxic bioreactors with activated sludge depending on the initial concentration of organic contaminants is carried out by Monod equation [6,7,8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
