Abstract:
Anaerobic complete mix bioreactor is one of the most essential treatment
technologies applied to industrial and municipal wastewater treatment. They are presumed
to offer the advantage of completely reducing or minimizing the volume of sludge and
increasing biogas production. Four identical 2L glass beakers (made up of borosilicate with
diameter of 13cm and height of 18cm) with working volume of 1500ml. All reactors
contain magnetic stirrer with same size magnetic bars that stirred continually with different
speeds to enhance well mixing environment in each reactor. The top headspace of every
beaker was sealed completely and two holes were made in each of them. A valve was fixed
in one of hole of every beaker.
The objective of this study is to evaluate the treatment efficiency of anaerobic
complete mix bioreactor for synthetic wastewater with the addition of sludge as a seed
under specific condition i.e mixing speed, mesophilic temperature range of 32±2 and
hydraulic retention time of 30 days and to test the effect of mixing speed on different
parameters inside the reactors effluent (pH, TDS, COD, BOD and TSS), sludge parameters
(pH, TDS, MLSS, MLVSS and particle size distribution) and some gases (CH4, CO2 and
H2) were also identified.
Based on results it was concluded that the physicochemical parameters of sludge
and effluent were very high on day 1 at different mixing speeds ( 100rpm, 200rpm, 300rpm
and 400rpm), but as the process started a gradual decrease was observed and best result
obtained at 400rpm on day 30. While in case of gases profiling the scenario was different.
On day one TDS in effluent was removed 2.5% while on day 30 at 400rpm 96% removal
efficiency was observed. Similarly the best percent removal efficiency of TSS, COD, BOD,
MLSS, MLVSS and TDS was observed 93.4%, 87%, 86%, 67%, 74% and 90%
respectively on day 30 with mixing speed of 400rpm. Furthermore, the gases were
identified on selected days. Optimum conditions for gases formation was found to be atiii
400rpm gives highest production rate of methane and carbondioxide but the lowest
hydrogen. So overall the removal efficiency was remarkable and it can run for longer
period of time as it is economical and energy efficient process and reduces the biomass
effectively.
