Page 149 - Materials Chemistry, Second Edition

130 Life Cycle Assessment of Wastewater Treatment

refractory natural materials that cannot be quickly degraded, biological treatment
is still a feasible decision.
The natural treatment of pharmaceutical wastewater incorporates both aerobic
and anaerobic treatment systems (Raj and Anjaneyulu, 2005; Afzal et al., 2007).

7.5.2.1.1 Aerobic Treatment
Biological aerobic treatment systems are also used extensively, often with limited
success due to the final clarification step. The clarifiers are susceptible to sludge
bulking and variations in total dissolved solids, often associated with batch pro-
cess production, which can cause destabilization of bacterial floc formation with a
consequential loss of biomass in the final effluent. These systems require constant
operator attention to adjust chemical dosing for the daily, even hourly, changes in
influent flow. Aerobic treatment is one of the regular connected innovations. It incor-
porates the activated sludge (AS) process, expanded air circulation–actuated sewage
handling, AS with granular enacted carbon, and layer bioreactors (Peng et al., 2004;
Chen et al., 2011).

1. Activated Sludge Process: The activated sludge strategy is generally used
as an oxygen-consuming suspended development approach. Despite the fact
that the activated sludge technique is powerful for the treatment of a few
types of low-quality pharmaceutical wastewater, the activated sludge pro-
cess is an outstanding procedure for removing different natural contami-
nants and natural carbon. The activated sludge process is the best-known
aerobic treatment, which has been observed to be effective for different
classes of pharmaceutical wastewaters. The conventional activated sludge
(CAS) treatment is an easy technique that depends basically on two param-
eters, the temperature and the hydraulic retention time (HRT). As well as
these, the presence of natural matter, COD, BOD, pH, and the presence of
non-biodegradable matter are different components that influence the effec-
tiveness of the AS strategy.
2. Membrane Bioreactor: The use of membrane bioreactors (MBRs) in waste-
water treatment is clearly becoming progressively more important, in light
of the fact that they offer a few favorable circumstances, that is, high bio-
degradation efficiency, a smaller impact, and less waste generation.
An MBR was operated in parallel with the CAS procedure (air circulation tank and
auxiliary settling tank). The biogenesis of the MBR was developed from inoculated
sewage from the municipal WWTP (air circulation bowl) and developed over a time of
around 1 month to achieve steady-state conditions. The water-driven maintenance time
was set to 14 h by directing the emanating stream, and the sludge retention time (SRT)
was unlimited on the grounds that no sludge was released from the reactor. In the last
decade, the use of MBRs for pharmaceutical wastewater treatment has attracted much
attention, as it is a financially practical option for water and wastewater treatment, par-
ticularly in view of the high SRT achieved inside smaller reactor volumes.
The MBR system helps manufacturers to meet and exceed all direct discharge
regulations while simplifying the treatment process. The MBR combines membrane