ETP

Effects of Effluents of Textile Industry in Environment & Daily Uses

Waste water from the industries destroys the quality of water body in which they are exposed affecting the marine-life.
It has also harmful effect on sewerage handling system and agricultural land.

The characteristics & effects of effluents are summarized below:
a) PH :- The waste water after PET (Polyester) Dyeing is acidic, whereas it is alkaline after reactive dyeing. So, if waster water is highly acidic then it causes;
1. Corrosion of Pipe Lines.
2. Destruction of aquatic life.
If waste water is highly alkaline then it causes;
1. Adverse effect on aquatic life.
2. Damages crops by impairing their growths.
b) Dissolved Solids: – Dissolved solids may be 0organic or inorganic in nature. They cause reduction of dissolved O2 in water. It creates some other problems like –
1. It causes disease and discomfort.
2. Scale formation in Pipe-lines and other equipments.
3. It accelerates algal growth.
4. It increases water hardness.
c) Suspended Solids :- it causes some bad effects like –
1. Suspended solids increase turbidity.
2. Interface with light transmitting properties of water.
3. Destroy photosynthesis and O2 transfer process.

What Type of Water Needs To Be Treated On ETP Plant in Textiles? BOD Means?

Effluent Treatment Plant is used in Textile Industry to save the Environment. A lot of pollutant water comes from different section of Textile Manufacturing unit which are really harmful for the natures.

Now we will know about what type of pollutant we find from the discharged water of textiles manufacturing unit. Even; we will know about how many BODS (Biological Oxygen Demand) this kind of water requires to make this environment friendly.

1. Desizing Unit Process: In desizing section
   several pollutants are found in water like Starch, Glucose, CMC, PVC Resins, Fat Oils etc. In this section the water are very much pollutant and needs high BOD which is 35 – 50% of total.
2. Scouring: In scouring section Sodium Hydroxide, Na2OO3 and other auxiliaries are found in water. Scoured water needs 30% of total BOD and they looks like dark colored and strongly alkaline.
3. Bleaching: In Bleached Water several pollutants are found like Bleaching powder, Chlorine, Sodium Hydroxide, Hydrogen per Oxide etc. This kind of water needs 5% BOD of total and in alkaline condition.
4. Mercerizing: In Mercerizing section just two types of pollutant are emitted. These are Sodium Hydroxide and Alkali. This kind of water needs 1% of BOD and water stays at strongly alkaline condition.
5. Dyeing: In dyeing section various Dyes, Salts, Acids, Alkalis, Sodium Hydro sulphite, Soap and Detergents can be found in water. This water is in highly colored and oily appearance and needs 6 % BOD of total.
6. Printing: Several pollutants exists in water like Dyes, Pigments, Thickener, Chemicals, Acids and Alkalies etc. This water is in highly colored and oily apprearance and needs 6 – 10% BOD of total.
7. Finishing: In Textile finishing section some pollutants like Traces of Starch, Tallow, and Different Finishing Agents are found. It requires low BOD which is about 2 – 4% of the total.

You can ask me about what is the BOD you meant above?

BOD (Biological Oxygen Demand)

The amount of Oxygen (O2) required for bring organism to oxidize organic materials is called biological oxygen demand (BOD). 1 Liter Water = 100 Mg Oxygen.

Effect of Effluents on Environment & Textiles Industry.

Water from the industries destroys the quality of water body in which they are exposed affecting the marine-life. It has also harmful effect on sewerage handling system and agricultural land.

The characteristics and effects of effluents are summarized below –

a)      PH Factor of Water:

The waster water after PET dyeing is acidic, whereas it is alkaline after reactive dyeing. If waster water is highly acidic then it causes 1. Corrosion in Pipe lines, 2. Destruction of aquatic life.  If waste water is highly alkaline then it causes 1. Adverse effect on aquatic life 2. Damages crops by impairing their growths.

b)      Dissolved Solids In Water:

Dissolved Solids may be organic or inorganic in nature. They cause reduction of dissolved O2 in water.  It also causes –

1. Disease & Discomfort.
2. Scale formation in piple-lines and other equipments.
3. It accelerates algal growth.
4. It increases water hardness.

c)      Suspended Solids In Water:

It causes –

1. Suspended solids increase turbidity.
2. Interface with light transmitting properties of water.
3. Destroy photosynthesis and O2 transfer process.

So, we see there are a lot of bad impact on environment and natures by effluent. We should have the Effluent Treatment Plant (ETP) to treat these garbage to save our nature and environment

Description of Effluent Treatment Plant Process Sequence in Textile Industry

I have already posted about the process flowchart of ETP – Effluent Treatment Plant. But it was too much shot and contained only the process name. Now I am describing each section of these.
h2>Primary Filtration of Waste Liquor

Waste liquor after pretreatment, dyeing, printing and finishing is subjected to primary filtration, in which removal of gross solids, such as waster threads, fabric pieces, lint’s, etc, takes place.

Cooling & Mixing

After primary filtration, the liquor passes to cooling and mixing tank in which uniform mixing of effluents from various process takes place. A paddle mixer is provided for mixing. Cooling of the effluent may be done with the help of cooling tower.

Neutralization

The effluent is pumped to a tank in which it is neutralized by acid or alkali dozing. The tank has an automatic dosing controller which at automatically control the dose of acid or alkali to maintain the required P^H .

Co-Agulation

Then the effluent is pumped to the co-agulation tank. Chemical co-agulation very effective for removal of color and suspended materials, aluminum, ferrous sulphates, ferric chloride, chlorinate dcopper etc. to increase the efficiency of co-agualtion, co –agulation gain may be added for example polyacrylate.

Setting & Separation of Sludge

Some of the soluble organic matter and light suspended solids will form a blanket of flocculent matter with the co-agulants. The blanket is skimmed of to another tank and the remaining solution is moved to pressure filter.

Pressure Filter

For pressure filtration vacuum pumps may be used to force through the filter and suspended flocks are collected in the pressure fine filter.

Discharging to Drain

After filtration the purified water sent to drain which eventually reach to the river or anywhere else.

Process Flowchart of ETP (Effluent Treatment Plant) of Textile

Effluent Transfer Plant is the essential part of a Textile Industry. As the consciousness about environment has been drastically increased; the research, talks about ETP also been increased.

ETP Plant consists of some basic steps. From the very beginning of Water accumulating to the final purified water has some processing procedures. These are –

Primary Filtration

Cooling & Mixing

Neutralization by Acid or Alkali Dozing

Chemical Co-agulation

Setting & Separation of Sludge

Sludge Pit

Filtration

Discharge To Drain

This is very basic steps of Effluent Transfer Plant. I will describe every  steps in the upcoming post.