Treatment Scheme for Trade and Domestic Effluent
Primary treatment - I: from process
The system will be designed to treat 125 m3/day of waste water. Effluent will be sending
to screen chamber, where coarse screen is placed to prevent coarse solids and debris
from entering the tank. From Screen chamber effluent will overflow to Oil & Grease trap
where floating oil & grease is removed from surface manually. The overflow from Oil and
Grease trap enters the Collection cum Equalization Tank - I. The equalization tank is
provided with acid & alkali dosing arrangement for pH neutralization & coarse bubble
diffusers will be provided to mix the wastewater. This effluent will be pumped to Flash
mixer where alum is dosed for coagulation.
Flash mixer effluent will overflow to Flocculator where poly is dosed for better
flocculation. Flocculator overflow to primary settling tank with hopper bottom tank
provided. Suspended solids
get settled at the bottom of settling tank & chemical sludge which is pumped to sludge
collection tank and clear supernatant will overflow to Anaerobic Sludge blanket / Stirred
Reactor (UASBR).
treatment (UASBR):
The system is designed to treat 48 m3/day of waste water. Primary treated high COD
effluent
shall enter the buffer tank. The effluent shall be overflow from the buffer tank for
anaerobic
treatment in the UASBR reactor. UASBR reactor consists of mainly feed distribution
network at
the bottom, sludge blanket at approx. mid height of reactor and the gas, liquid, solid
separator at
the top of the reactor. In UASBR process the bacteria responsible for digestion process
are
present in the form of sludge blanket. The bacteria grow and reside as bacterial flocs
suspended
in the Up flow effluent stream. The bacteria take upon organic content of wastewater to
metabolize it and produce biogas and biomass. UASBR operates in the mesophillic range
of
temperature, i.e. 360C – 400C. The pH inside the reactor is usually kept around 7.2 while
proper
ratio of volatile acid and alkalinity is maintained.
Biogas is collected at the top of the reactor and burnt in flare stack. The anaerobically
digested
effluent is collected to holding tank along with low COD effluent, utilities blowdown &
domestic
wastewater and sent to (Aerobic) Bioreactor Tank for further treatment.
Secondary Treatment (Aerobic):
The system will be designed to treat 48 m3/day of waste water. The neutralized effluent
from
anaerobic treatment waste water, utility blow downs & domestic waste water will be
treated in
the bioreactor. In the bio reactor, dissolved organic material is degraded by the micro–
organisms
present in the bio reactor. Oxygen required for the oxidation of organic matter will be
provided by
means of additional diffuser aeration system which will mix the contents of the
bioreactor also.
The mixed liquor will overflow into Secondary Settling Tank (SST). In the secondary
settling tank,
solid-liquid separation takes place and solids i.e. biomass will settle at the bottom of the
tank.
Tertiary Treatment:
The clear effluent from the intermediate tank will be pumped by tertiary Feed pumps
through the pressure sand filter (PSF) & activated carbon filters (ACF). The final treated
effluent will be feed to Reverse Osmosis (RO).
RO System
Reverse Osmosis is at present a proven technology used to recover good quality water
for process use. The outlet from ETP will be passed through RO where the dissolved
solids are separated in the form of Reject & treated water free from dissolved solids
(Permeate – 151 CMD) is utilized for cooling tower and boiler feed. Reject of RO (38
CMD) shall be feed to the Evaporator to achieve Zero Liquid Discharge (ZLD) scheme.
Multiple Effect Evaporator :
Reject of RO (38 CMD) will be evaporated in Multi effect evaporator to achieve zero
liquid discharge. Salts from MEE will be disposed to CHWTSDF while condensate (46
CMD) will be recycled to utilities.
Sludge Handling:
Primary sludge and excess biomass from the secondary treatment will be passed through
filter press. Solid sludge cake from the filter press will be sent for disposal to Hazardous
waste disposal site. The filtrate from the filter press will be drained to the intermediate
tank.
Basic Working Principle of a Bioreactor
A bioreactor is a controlled vessel or system where biological reactions occur, typically
involving microorganisms, enzymes, or cells. The primary goal is to optimize conditions
(temperature, pH, oxygen, nutrients) to maximize biological productivity.
Key Steps in Bioreactor Operation
1. Sterilization – The bioreactor and its contents (media, air, etc.) are sterilized to
prevent contamination.
2. Inoculation – The desired microorganisms or cells are introduced into the bioreactor.
3. Cultivation – Optimal conditions (temperature, pH, oxygen levels, agitation) are
maintained to ensure proper growth and metabolism.
4. Monitoring & Control – Sensors track parameters like dissolved oxygen, pH,
temperature, and nutrient levels. Automated systems adjust conditions accordingly.
5. Harvesting – The final product (e.g., enzymes, biofuels, antibiotics) is extracted and
purified.
Essential Equipment in a Bioreactor
1. Vessel – The container where the biological process occurs, usually made of stainless
steel or glass.
2. Agitator & Impellers – Used to mix the medium and ensure even distribution of
nutrients and gases.
3. Aeration System – Supplies oxygen (in aerobic processes) using spargers or air
diffusers.
4. Sensors & Probes – Measure temperature, pH, dissolved oxygen, and other
parameters in real-time.
5. Control System – Automated software/hardware to regulate bioreactor conditions.
6. Heating/Cooling System – Regulates temperature through external jackets or coils.
7. Inlet/Outlet Ports – Allow the addition of nutrients and removal of waste or
products.
Pressure Sand Filter (PSF) – Working Principle & Equipment
A Pressure Sand Filter (PSF) is a water filtration system used to remove suspended
particles, turbidity, and some microbial contaminants from water. It is commonly used in
water treatment plants, industrial processes, and wastewater treatment.
Working Principle of a Pressure Sand Filter
1. Water Inflow: Raw water enters the filter under pressure.
2. Filtration Process: The water passes through multiple layers of sand and gravel.
Suspended particles get trapped in the sand bed while clean water flows through.
3. Outlet of Filtered Water: The filtered water exits from the bottom of the filter.
4. Backwashing: Over time, trapped particles clog the sand bed, reducing efficiency.
The system undergoes a reverse flow (backwashing) to clean the sand and remove
accumulated impurities.
5. Reuse/Discharge: The cleaned sand is ready for filtration again, and the waste from
backwashing is discharged appropriately.
Key Equipment in a Pressure Sand Filter
1. Pressure Vessel: A closed cylindrical tank (made of MS, FRP, or SS) that holds the
sand and gravel layers.
2. Filter Media: Typically consists of:
o Coarse Gravel (at the bottom) – Provides support.
o Fine Sand & Silica Sand – Traps suspended particles.
o Anthracite (optional) – Enhances filtration efficiency.
3. Inlet & Outlet Pipes: Allow water to enter and exit the filter.
4. Control Valves: Regulate water flow and pressure.
5. Manometer or Pressure Gauge: Monitors pressure drop across the filter, indicating
when backwashing is needed.
6. Backwash System: Includes valves and a pump for reversing water flow to clean the
filter media.
Applications of Pressure Sand Filters
✔️ Drinking water treatment
✔️ Industrial water purification
✔️ Wastewater treatment plants
✔️ Cooling tower water filtration
✔️ Swimming pool water filtration
Activated Carbon Filter (ACF) – Working Principle & Equipment
An Activated Carbon Filter (ACF) is a water or air filtration system that removes organic
contaminants, chlorine, odor, taste, and some chemicals using activated carbon. It is widely
used in water treatment, air purification, and industrial processes.
Working Principle of an Activated Carbon Filter
1. Adsorption: Contaminants in the water or air stick to the porous surface of the
activated carbon due to its high surface area.
2. Chemical Reactions: Some impurities, like chlorine and certain organic compounds,
undergo chemical changes and become harmless.
3. Filtration: Particulate matter and sediments are also trapped, improving water clarity.
4. Outlet of Purified Water/Air: The clean water or air exits the system, free from
odor, color, and harmful chemicals.
Key Equipment in an Activated Carbon Filter System
1. Pressure Vessel: A tank (made of MS, FRP, or SS) that houses the activated carbon
bed.
2. Activated Carbon Media: Made from materials like coconut shells, coal, or wood,
processed to have a high adsorption capacity.
3. Inlet & Outlet Pipes: Allow water or air to flow through the system.
4. Control Valves: Regulate flow and pressure.
5. Pressure Gauge: Monitors pressure drop to indicate when the filter needs
maintenance or replacement.
6. Backwash System (Optional): In water treatment, backwashing helps remove
trapped particulates and extends the filter’s life.
Applications of Activated Carbon Filters
✔️ Water Purification – Removes chlorine, organic pollutants, and improves taste & odor
✔️ Wastewater Treatment – Eliminates industrial chemicals and organic matter
✔️ Air Filtration – Removes VOCs (volatile organic compounds), odors, and toxic gases
✔️ Food & Beverage Industry – Ensures purity in production processes
✔️ Pharmaceuticals – Removes impurities from process water
Multiple Effect Evaporator (MEE) – Working Principle & Equipment
A Multiple Effect Evaporator (MEE) is a system used for concentrating solutions,
typically in industries like food processing, pharmaceuticals, and wastewater treatment. It
improves energy efficiency by using steam multiple times across several stages (effects).
Working Principle of a Multiple Effect Evaporator
1. Steam Supply (First Effect): Steam is introduced into the first evaporator chamber,
where it heats the solution.
2. Vapor Generation: The heated solution evaporates, producing vapor.
3. Heat Reuse (Subsequent Effects): The vapor from the first effect is used as the
heating source for the second effect. This process continues across multiple effects,
with each stage operating at a lower pressure and temperature.
4. Concentration Increase: As water evaporates, the solution becomes more
concentrated.
5. Condensation & Recovery: The condensed vapor (distillate) is collected, and the
final concentrated product is discharged.
By reusing vapor as a heat source, MEE significantly reduces steam consumption and
improves energy efficiency.
Key Equipment in a Multiple Effect Evaporator System
1.
2.
3.
4.
5.
6.
7.
Evaporator Effects (Chambers): Multiple vessels where evaporation occurs.
Steam Supply System: Provides steam for the first effect.
Heat Exchangers: Transfer heat from vapor to the solution in subsequent effects.
Condensers: Convert vapor back into liquid (distillate).
Pumps & Circulators: Move the liquid between effects.
Vacuum System: Reduces boiling points to enhance efficiency.
Control Valves & Sensors: Regulate temperature, pressure, and flow rates.
Applications of Multiple Effect Evaporators
✔️ Sugar & Food Industry – Concentrates juices, milk, and syrups
✔️ Pharmaceuticals – Produces high-purity concentrated solutions
✔️ Wastewater Treatment – Removes water from industrial waste streams
✔️ Paper & Pulp Industry – Concentrates black liquor for energy recovery
✔️ Chemical Processing – Used in dye, fertilizer, and salt industries