A detail about various Post Treatment Techniques for UASB Reactor.

1. “An Overview of Post Treatment of
UASB Effluent”
Presented By
HARIOM GUPTA
(14UCH090)
Project Guide
Dr. Swarup Biswas
Assistant Professor, Chemical Engineering
NIT Agartala

2. CONTENTS:
 Introduction
 Objective
 Why do we need Effluent Post Treatment
 What is Effluent Post Treatment
 Major Post Treatment Techniques
 Conclusions
 References

3. Introduction:
Post Treatment of UASB effluent covers the various techniques and
processes used to treat the effluent after secondary treatment , that have
been contaminated in some way by pathogens, and anthropogenic
industrial and commercial activities prior to its release into environment .
This effluent contains several pollutants, which can be removed with
the help of an effluent treatment process.
Effluent Treatment technologies treat this effluent and make it free
from all undesirable impurities present in suspension or dissolved form.

5. Objective:
To prepare a pilot scale UASB reactor
Find out the removal efficiency of various Post Treatment Techniques
Find out the economical Post Treatment Options
Compare the efficiencies of Sand-Algae Filtration and Slow Sand Filtration

6. Why do we need Effluent Post Treatment :
 To prevent groundwater pollution
 To prevent soil
 To prevent sea shore
 To prevent marine life
 To protect public health
 To reuse the effluent
 For agriculture
 For industrial recycle
 Rectifying problems related to accumulation of wastewater

7. What is Effluent Treatment:
Effluent treatment is tertiary treatment, meant for
the removal of pollutants and undesirables which are not removed in
primary and secondary treatment processes.
These pollutants may include inorganic compounds such as
Phosphorous or Nitrogen which may support algal growth in receiving
water.

9. Major Post Treatment Techniques:
Polishing ponds or final polishing units
•Used to improve the quality of effluents from efficient anaerobic sewage treatment
plants like UASB reactors.
•The main objective of polishing ponds is to improve the hygienic quality, measured
by the concentration of two indicator organisms: helminth eggs and faecal coliforms
(FC).

10. Overland flow process
• In this method, the vegetation, associated with the top soil layer, acts as a filter,
removing the nutrients and providing conditions for the retention and transformation of
the organic matter contained in the sewage.

11. Submerged aerated bio filter
• A submerged aerated bio filter (SAF) consists of a tank filled with porous
material, through which sewage and air flow permanently.
• In almost all the existing processes, the porous medium is maintained totally
sub-merged by the hydraulic flow.
• The bio filters are three types
1)Solid phase2)Liquid phase 3)Gas phase

12. Trickling filter
•This association (UASB reactor + TF) may contribute significantly to the reduction of
the power and operational costs of the treatment plant.
•Though the trickling filters have great potential in wastewater treatment systems,
mainly due to the advantages of their simplicity and low operational cost.

13. Anaerobic filter
•Among the high rate anaerobic reactors, anaerobic filters (AF) looks promising for
municipal wastewater treatment.
•Nowadays, anaerobic filters, after UASB reactors, are being used in cities with
population larger than 50,000 inhabitants.

14. Dissolved air flotation
•The DAF units are compact in nature and require less operational cost. However, the
removal efficiency of ammonia, nitrogen, and fecal coli-forms is poor.
•Dissolved air flotation is a water treatment process that clarifies wastewater by the
removal of suspended matter such as oil or solids.

15. Constructed wetlands
•Constructed wetland use less energy and require less skilled labor.
•Constructed wetlands are small artificial water treatment system consisting of
one or more shallow treatment cells.

16. Activated sludge process
•Name itself suggests settled sludge containing living or active microorganisms. It may be
completely mixed flow or mixed flow system.
•The process is aerobic with O2 being supplied by dissolution from entrained air. Activated
sludge processes consist of a tank, within which the biological reaction occurs, a settling
tank, a recycle pumping system and an aeration system.

17. Expanded granular sludge bed reactor
•Expanded granular sludge bed (EGSB) reactor is mainly used to control preferential
flows, hydraulic short cuts and dead zones which occur in UASB reactor.

18. Ozonation
•Ozone is the triatomic form of oxygen and it is composed of three oxygen atoms.
•To generate a sufficient quantity of ozone for a wastewater treatment plant,
ozonators developing a corona discharge are used. The ozonation eliminates odor,
reduces oxygen demanding matter, turbidity, surfactants and removes most colors.

19. Aerated fixed bed
The UASB reactor effluent is post treated by an aerated fixed bed (AFB)
reactor under aerobic condition and subsequently become the final effluent after
passing through the settling tank. AFB reactor is aerated from all over the bottom.
Bio filter
Bio filter (BF) is considered as the primary filters and is currently under use
in highly dense areas of Brazil. The sludge in these bio filters is usually unstable
and requires stabilization. In this mechanism low sludge formation and energy
savings occurs. Also the anaerobic digestion of the sludge removed from the bio
filter by backwashing. It is accomplished directly in the UASB reactors. Excel-lent
quality of the final effluent for the domestic sewage can be obtained by UASB
reactor + BF system.
Zeolite ion exchange
For the treatment process natural zeolite is used. After the use of zeolite in
the reactor it is collected for the regeneration process and is regenerated by
nitrification process. Zeolite application reduces TAN (total ammoniacal nitrogen).
The reduction effect of the zeolite is due to the interstitial spaces in its lattice
framework which allows the replacement of the nitrifying ions.

20. Conclusions:
The studies carried out by many researchers in full-scale, pilot scale and
laboratory scale systems which demonstrated that the up-flow anaerobic sludge
blanket reactor is a reliable and simple technology for treatment of domestic
sewage. However, the UASB reactor effluent still contains high organic
content and high counts of coli-forms in the discharge. So to achieve high
quality of effluents, post treatment units are required. The post-treatment units
for UASB reactor effluents proved that they are feasible and efficient in
reducing organic content and also pathogens at different conditions. There is a
tremendous need to develop reliable technologies for the treatment of domestic
wastewater in developing countries. It is not easy to select one post-treatment
unit which is sufficient enough to fulfil all the requirements. But UASB + CW
may be a better combination which may satisfy the basic needs of a treatment
plant for a developing country.

21. References:
Mungray et al.
Shankar Yelmame et al.
Wikipedia.

22. THANK
YOU