This document discusses various biotechnological approaches for wastewater treatment, including engineered biosorbents for heavy metal removal, displaying metal binding peptides on microorganisms, and designing strains for enhanced biodegradation. It describes common wastewater treatment processes like the trickling filter, activated sludge process, and anaerobic digestion. Finally, it discusses using these biotechnological methods to treat wastewater from textile and desiccated coconut industries.

1. ENVIRONMENTAL BIOTECHNOLOGY
Course code : 322
[Type the document subtitle]
Muhammad Saad Mughal
SP13-BTY-006
To
Dr. Sabaz Ali Khan
Date: 21-09-15
BIOTECHNOLOGICAL APPROACHES TOWARDS WATER
WASTE MANAGEMENT

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BIOTECHNOLOGICAL APPROACHES TOWARDS WATER
WASTE MANAGEMENT
Recent Trends in Biotechnological Processes for the Treatment of
Wastewaters
Engineered biosorbents for heavy metal removal from wastewaters.
Engineering of sulphate reduction pathway through use of robust bacterium E. coli (through
expression of serine acetyltransferase and cystenie desulfhydrase).
Display of metal binding petites on the cell surface of specific microorganisms for enhanced
metal chelating.
Designer strains for enhanced biodegradation (designer biocatalyst).
Pesticide degradation.
Pseudomonas putida redesigning pathway through construction of hybrid strain for enhanced
biodegradation of benzene, toluene and parazylene.
Industrial wastewater is a type of wastewater produced by industrial activity, such as that of
factories, mills and mines. It is characterized by its large volume, high temperature, high
concentration of biodegradable organic matter and suspended solids, high alkalinity or acidity,
and by variations of flow.
Accomplish waste Treatment
Trickling Filter, Rotating Biological Contactor, Activated Sludge Process, Lagoons, Oxidation
Ponds, Microorganisms are used to destroy waste materials.
Microorganisms include bacteria (aerobic and anaerobic), fungi, algae, actinomycetes
(filamentous bacteria).

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Stages oftreatment
Primary this is only a physical separation to remove solid matter. Effluent is allowed to settle for
a few hours.
Secondary the organic and nutrient load is decreased by microbial activity up to 95% so that the
effluent is of a quality and to be able to go into rivers.
Tertiary this is a complete treatment, but it is very expensive and not used much.
Overall Treatment Processes
Fig 1. Wastewater from various areas go through a lot of necessary steps in order to gain the
disinfectant water which can be used as a source in different fields.(a) In primary clarifier solids
are treated to reuse (b) From secondary clarifier waste is collected and water is again projected to
aeration Basin.
Secondary treatment can be divided into
Anaerobic
Complex series of digestive and fermentative reactions by a mixture of bacteria. It can remove
95% BOD. This is the choice if there is a lot of insoluble matter , cellulose, industrial waste.

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Degradation is carried out in large tanks – sludge digesters or bioreactors. Molecular components
are digested and fermented to FA, H2, CO2. FA then to acetate, CO2 and H2. These are substrates
for methanogenic bacteria to make methane. Major products are methane and CO2. Used or
burnt off.
Anaerobic sludge digestion
Anaerobic sludge digestion
Fig1(a).Conventional sludge
digestion process. Sludge in
treated, digested and convert
to stable form with a lot of
by-products release during
steps.
Fig1(b). This is Biogas (as a
byproduct) production from a
decomposition process by
microbes. Here sludge is used
and adjusted properly the
digester to avoid any technical
issue.

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Aerobic
There are several kinds of aerobic decomposition processes. Trickling filter and activated sludge
are the most common. Trickling filter is a bed of crushed rock, ~2m thick. Wastewater is sprayed
on the top (UWI plant). Liquid slowly passes through the rock, organic matter absorbs to the
rock and microbial growth takes place. Complete mineralization of organic matter takes place.
Most common is activated sludge. Wastewater is mixed and aerated in a large tank
Trickling Filter

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Fig 2. In this pre settled water is sprayed over filter. As water moves from pores of filter organics
are degraded by the biomass covering the filter material.
BioremediationTechnology
Bioremediation is the use of micro-organism metabolism to remove pollutants. Technologies can
be generally classified as in situ or ex situ. In situ bioremediation involves treating the
contaminated material at the site, while ex situ involves the removal of the contaminated material
to be treated elsewhere
Bioreactors technologically are the most sophisticated category of environmental bioremediation.
Bioreactors offer a much faster means of waste biodegradation than land treatment and more
control over reaction conditions and effluent quality than simple biofilters. Degrade organic
substances that are hazardous to living organisms and convert the organic contaminants into inert
products.
Activated Sludge
Microbial activity in activatedsludge
Fig2 (a).

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Slime forming bacteria like Zoogloea grow and form flocs. Small animals and protozoa attach to
these. Process of oxidation is similar to the trickling bed. Effluent containing flocs goes to
settling tanks. Flocs settle. Some floc material is recirculated. Water spends 5-10 hours in sludge
tank, too short for complete oxidation. Main process is absorption of organic matter to the floc.
BOD of liq waste is reduced by ~95%. Most BOD is in the flocs. BOD reduction then takes
place by digestion of the flocs in the sludge digestor.
Comparing Advantages.
Anaerobic treatment has advantages over aerobic. Reduction of excess sludge production up to
90%
 Production of energy in the form of methane gas
 No or very little use of chemicals
 Lower treatment costs
 High flexibility, since it can be applied to very different types of effluents (higher and
lower loading rates, mesophilic or thermophilic conditions, more or less complex
wastewaters, etc.)
 Anaerobic organisms can be preserved unfed for a long time, which makes it possible to
treat wastewaters that are generated with longer (seasonal production) or shorter
(holidays and weekends) pauses in between .
Advantages of Biotechnological Processes for the Treatment of Industrial
Wastewaters
 Truck loads of animal dung materials required for start up of conventional treatment
system can be reduced.
 Energy efficient systems.
 Minimum nutrient requirements as compared to conventional processes.
 Easy to monitor and adopt appropriate corrective measures in case of upset of the
treatment plant.
 Cost effective processes.

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Development of Biotechnological Processes for Treatment of Wastewaters
Generatedfrom Textile and DesiccatedCoconutIndustries
Textile
Developed biotechnological processes (aerobic /anaerobic-aerobic) on bench scale for treatment
of textile wastewater. In anaerobic system with a HRT of 3.8 h could remove COD up to 53.4%,
while the corresponding HRT in the CMAS system (23.6 h) could remove COD up to 74 %.
Pretreatment of textile wastewater with aqueous oxidative processes enhanced the
biodegradability of textile wastewater more than 99%.
Development of Bench Scale Reactor for the Biological Treatment of Waste
Containing Hexachlorohexane (HCH)
Future R&D scope
Evaluation of simpler electron donor compounds as bio-stimulants for bioremediation of HCH
contaminated soil. Development of a microbial consortium capable of degrading pesticide
contaminated soil containing HCH, endosulphan, and other POPs.
References
www.slideshare.net/shuaibmusa2012/biotech-presentation-29686787
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