WASTEWATER TREATMENT

WASTEWATER TREATMENT-EFFLUENT TREATMENT PLANT (ETP)

What is wastewater treatment

Wastewater:

Wastewater is any water that has been adversely affected in quality by phylogeny influence.

Usually refer to sewage treatment, industrial wastewater treatment or domestic wastewater treatment

process of removing contaminants from sewer water, both runoff and domestic

Introduction

ETP is the most important subject of environmental science. It is directly related to the environment. If the effluent is not treated with the proper processes, the environment can be contaminated. So we should take proper steps for Effluent Treatment

Goals

To produce a waste stream (effluent)

To produce solid waste (sludge)

To discharge or reprocess them back to the setting

To manage water discharged from homes, businesses, and industries to scale back the threat of pollution.

Where does wastewater come from?

Residences (kitchen, bathroom)
Commercial institution
The industrial institution (usually require specialized treatment process)

Composition

PROCESSES

3 stages of effluent treatment

Primary

solids are separated

Secondary

the dissolved biological matter is converted into a solid mass by using water-borne bacteria
95% of the suspended molecules should be removed

Tertiary

biological solids are neutralized then disposed, and treated water could also be disinfected with chemicals or physically

Types of treatment

Mechanical treatment

Influx (Influent)
Removal of large objects
Removal of sand and grit
Primary Sedimentation

Biological treatment

Trickling bed filter
Activated sludge

Chemical treatment

Disinfection

What is the biological treatment?

Use microorganisms to remove the contaminant.

Knowing the compositions

 choose the right system to treat and suitable for requirements.

Bacteria’s remarkable ability.

Take energy from the oxidation of organics for metabolism and building cells

Favorable conditions for growth

This metabolic activity can remove contaminants.

EFFLUENT TREATMENT PROCESS

CAPACITY – 400 CU METER

Typical waste treatment

Preliminary treatment

Remove large objects
Ex: sticks, rags, toilet paper, tampons
Raked screen
Clog equipment in a sewage treatment plant

Primary treatment

typical materials that are removed throughout primary treatment embrace

fats, oils, and greases (aka FOG)
sand, gravels, and rocks (aka grit)
larger settleable solids including human waste, and
floating materials

Equalizer Tank

The function of Equalizer Tank

Equalization tanks area unit sometimes equipped with agitators or aerators wherever a mixture of the waste material is desired and to stop suspended solids from subsidence to rock bottom of the unit.
Equalization tanks can be mixing of acid and alkaline wastes in homogenously.
Dampening of organic fluctuations  forestall shock loading of biological systems
pH control  Minimize chemical requirements for neutralization
Minimize flow surges to physical-chemical treatment. Permit chemical feed rates compatible with feeding equipment

The function of Equalizer Tank

Mixing is required for:

- Adequate equalization
- Prevent settlement of solids
- Oxidation of reducing compounds
- Reduction of BOD by air stripping (limited)

Oil & Grease Separation Tank

Why did Oil & Grease need to Separate?

Grease and oil in the wastewater can causes problems by separating from the wastewater and accumulating on the inside of sewer pipes.
Over time, these deposits get larger as more grease and other solid material builds up which creates offensive odor and an unhealthy environment.
The cleansing of grease deposits from sewers is tough and might be dangerous and is meted out at hefty value.

Secondary treatment

Degrade biological content (dissolved organic matter) of the waste product

Ex: human waste, food waste, soaps, detergent

Added bacteria and protozoa into a sewage
3 different approaches

Fixed film system
Suspended film system
Lagoon system

Three approaches

Fixed Film Systems

grow microorganisms on substrates like rocks, sand or plastic
wastewater is spread over the substrate
Ex: Trickling filters, rotating biological contactors

Trickling Filter

Trickling filters

The trickling filter or bio-filter consists of a bed of permeable medium of either rock or plastic
made of coke (carbonized coal), stone chips or specially invented plastic media
Microorganisms become hooked up to the media and kinda biological layer or fixed-film.
Organic matter within the waste material diffuses into the film, wherever it's metabolized.
Periodically, parts of the film slough off the media
Spread wastewater over microorganism

Principle of Trickling filtration

Aeration Tank 1 & 2

The function of Aeration Tank

In wastewater treatment processes, aeration

introduces air into a liquid, providing an aerobic

environment for microbial degradation of organic

matter. The purpose of aeration is two-fold:

1) to provide the desired atomic number 8 to the metabolizing

microorganisms and

2) to produce mixture so the microorganisms acquire intimate contact with the dissolved and suspended organic matter.

Activated sludge tank

a mixed community of microorganisms

Both aerobic and anaerobic bacteria may exist

Biological floc is formed

Clarifier Tank

Discharge Tank

Tertiary treatment
remove disease-causing organisms from wastewater
3 different disinfection process

Chlorination
UV light radiation
Ozonation

What can effluent use for?

discharged into a stream, river, bay, lake or ground

used for the irrigation of a golf course, greenway or park

If it’s sufficiently clean, it can be used for groundwater recharge

Sludge disposal

Superheat sludge and convert into tiny granules that area unit made in atomic number 7

Sell it to a local farmer as fertilizer

Spread sludge cake on the field

Save landfill space

Dry Sludge Tank

Test of water processed by ETP

pH
Dissolved Oxygen (DO)
Chemical oxygen demand (COD)
Biological oxygen demand (BOD)
Total Dissolve Solid (TDS)
Sludge in Aeration Tank

Dissolve Oxygen (DO)
The term DO is used to describe the amount of oxygen dissolved in a unit volume of water. DO is essential for the maintenance of healthy canal/lakes/rivers.

It is a life of the power of water to sustain aquatic life.

DO content of water is influenced by the sources of wastewater, temp, treatment process

Importance of DO in ETP

The presence of atomic number 8 in water may be a sensible sign.

The depletion of DO in water supplies can encourage the microbial reduction of nitrate to nitrite and sulfate to sulfide. In a lake/canal/river the DO is about 8 ppm. The minimum DO level of 4-5 ppm is desirable for the survival of aquatic life.

Dissolved atomic number 8 (DO) is additionally useful to boost the oxidization method by providing atomic number 8 to aerobic microorganisms in order that they will with success flip organic wastes into inorganic byproducts.

In order to metabolize food and reproduce, every organism (or bug) should have a minimum of zero.1 to 0.3 mg/L DO.

Chemical Oxygen Demand (COD)

COD may be alive of the capability of water to consume atomic number 8 throughout the decomposition of organic matter and therefore the oxidization of inorganic chemicals like ammonia and nitrate.

Biological Oxygen Demand (BOD5)

BOD5 is that the quantity of dissolved atomic number 8 required by aerobic biological organisms in a very body of water to breakdown organic materials gift in a very given water sample at an explicit

temperature over a specific time period.

Why its need to reduce the BOD level?

If water with a large amount of BOD is discharged into the environment, it can deplete the natural oxygen resources.

Heterotrophic bacterium utilizes deposited organics and atomic number 8 at rates that exceed the oxygen-transfer rates across the water surface.

This can cause anaerobic conditions, which leads to noxious odors.

It can even be harmful to aquatic life by reducing dissolved atomic number 8 concentrations to levels that cause fish to suffocate.

The end result is an overall degradation of water quality.

Analysis of wastewater