report on effluent treatment plant (etp) operation and maintenance of interstoff apparels ltd. (ial)

Report on Effluent Treatment Plant (ETP)

Operation and Maintenance of Interstoff

Apparels Ltd. (IAL)

Submitted By:

Name: Quock San

Designation: Management Trainee

ETP (TSD), ID No.: 430033

Email: [email protected]

Acronyms and Abbreviations

BOD Biological Oxygen Demand

BOD5 5-Days Biological Oxygen Demand

COD Chemical Oxygen Demand

DO Dissolve Oxygen

DoE Department of Environment

ECC Environmental Clearance Certificate

ETP Effluent Treatment Plant

IAL Interstoff Apparels Ltd.

pH Measure of Acidic or Alkaline condition of Water

SETL South East Textiles Ltd.

TDS Total Dissolved Solid

TSS Total Suspended Solid

Introduction

Factory Profile:

Interstoff Apparels Ltd (IAL) comprises of the latest, most technologically advanced 100% export

oriented private limited company with composite knitting, dyeing, finishing and apparel manufacturing

plants situated at Chandra, Kaliyakoir, Gazipur, Bangladesh. It’s started business in operation since

2002. Corporate office and factory are located at same location and take up an area of more than 131000

square feet and 3, 50,000 square feet for production process respectively. Interstoff Apparels Ltd are

manufacturing all type of knitted garments such as Fashion T-shirt, Polo Shirts, Knitted Shorts, Legging

Night Wear, Kid’s, Men’s , Girl’s and School wear etc. There are more than 4,000 experienced workers

are employing in the total process. The Garments unit alone has about 57 lines with a monthly

production capacity is 2.0 million pieces that is exported mostly to Europe and USA.

The main buyers include renowned brands such as, Marks & Spencer (M&S), Tesco, Kohl’s, Sainsbury,

Gap, Ralph Lauren, Debenhams, Gymboree, H&M, Zara, Mother Care, Tchibo, Cotton on, Mango etc.

IAL prides itself in meeting all international standards for good work environment that is compliant with

both national and international rules. The company is compliant with ‘Children’s wear Safety

Requirements’ and provides a ‘Completely Metal Free Environment’ for workers’ health and safety. The

factory is fully approved by several globally accepted Certification bodies like WRAP, ISO 9001:2008,

Organic, SGS and Oeko-tex Certified. IAL is also FAIRTRADE certified by the FLO-Cert Trade

Certification Committee (FLO ID: 18123).

Existing Waste Water Management at IAL:

IAL installed an Effluent Treatment Plant of 75 m3/Hr capacity which is running 24 Hr in a day. By

nature, our ETP is Bio-logical with Chemical namely Bio-Chemical plant. This treatment is done by

four stages such as preliminary, primary, secondary and tertiary treatment. Waste water comes from

mainly dyeing and washing through a trench to equalization tank so for preliminary treatment is done by

screening by using net or sieve for removal of large solids such as rags, sticks, grit and grease that may

result in damage to equipment or operational problems at different stages of trench.

After primary filtration, the liquor passes to cooling and mixing tank in which uniform mixing of

effluents from various processes takes place. An air mixer is provided for mixing uniformly for aeration

and neutralization of effluent at equalization tank. The effluent is pumped to a tank in which it is

neutralized by cultural bacteria namely Bio-formula dozing. The tank has an automatic dosing controller

which at automatically control the dose of acid or alkali to maintain the required PH. Then the effluent is

pumped to the coagulation tank and to mix up different chemicals such as lime, ferrous sulfate etc.

Chemical coagulation is very effective for removal of color and suspended materials, aluminum, ferrous,

ferric chloride, chlorinate d-copper etc. To increase the efficiency of coagulation, chemical may be

added for example polyelectrolyte. Some of the soluble organic matter and light suspended solids will

form a blanket of flocculent matter with the coagulants. The blanket is skimmed off to another tank and

the remaining solution is moved to dual media filter and centrifuge hydro extractor. After filtration the

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

It can be noted here that the ETP is able to deliver treated waste water within the permissible limit of the

DOE. From the outlet quality of ETP, it can be mentioned here that though the water cannot be directly

use in the dyeing, washing and finishing process. It is quite good to use in any other non-process like

cleaning of dyeing floor, toilet flashing, car washing and gardening etc.

Table-01: Characteristics of Waste and Treated Water of ETP_IAL with National Standard

Parameters Properties of Inlet Waste

Water

Properties of Outlet

Treated Water

Discharge Water

Standard according

to ECR, 97

pH 8.3-10.8 7.2-7.7 6-9

DO (mg/l) 0.0 4.9-5.5 4.5-8

BOD (mg/l) 150-190 38-42 < 50

COD (mg/l) 260-480 135-175 < 200

TDS (mg/l) 2500-2900 1320-1940 < 2100

TSS (mg/l) 250-280 80-120 < 150

Temperature (°C) 37-45 30-32 40-45

Color (Pt. Co.) 185-245 120-150 -

Odor Light Bad Smell Slight Smell Odorless

Figure-01: Process Flow Diagram of ETP_IAL

Tanks Retention Time Calculation and Volume of ETP_IAL

ETP Capacity: 75 M3/Hr

Current rate of Effluent Treatment: 55~60 M3/Hr

Table-02: Retention Time Calculation & Volume of the ETP Tanks

Retention Time (Hr)

Sl. No. ETP Tanks Tanks Volume (M³) Rated Actual

1 Equalization - 01 165 2.20 2.90

2 Equalization - 02 238 3.17 4.18

3 Bioreactor - 01 175 2.33 3.07

4 Bioreactor - 02 215 2.87 3.77

5 Flash Mixing 19 0.25 0.33

6 Flocculation 11 0.15 0.19

7 Tube Settler - 01 45 0.60 0.79

8 Tube Settler - 02 58 0.77 1.02

9 Tube Settler - 03 58 0.77 1.02

10 Tube Settler - 04 45 0.60 0.79

Total Retention Time Hr 13.72 18.06

Chemical Dosing:

The dosing of coagulant solution must be prepared as the concentration of more or equal to 5% solution.

The rate of the solution is maintained by trained personnel depending on the quality of the waste water.

This dosing rate is determined by Jar test. Dosing rate of coagulant varies from 15 to 20 ml/L and dosing

rate of flocculent varies from 0.1 to 0.2 ml/L. Biological treatment process reduces TSS and BOD to a

great extent. The dosing rate of Bio-formula in our ETP is 250 g/day (a single packet) and dosing in the

equalization tank or bioreactor tank.

Maintenance of the ETP:

ETP’s goal is to treat waste water and deliver a quality product that meet the standard for environmental

discharge or reuse. Like any other facility a waste water treatment plant require continuous maintenance.

So, maintenance of ETP plant as a whole is very important. There are different types of maintenance

strategies; these are Routine maintenance, Mechanical maintenance, Breakdown maintenance and

Annual shut down maintenance. In our ETP Routine maintenance is done in every Friday and annual

shut down maintenance during Eid vacation to maintain standard quality of the discharge water. Bar

screens are cleaned about 3-4 times in everyday.

Sludge Treatment and Handling:

The sludge which is generated in the Flash mixing tank, Flocculation tank, Bio-Reactor and Tube settler

1, 2, 3 and 4 is taken to sludge sump. Here also aeration is carried out. The heavy sludge waste is then

pumped to a sludge thickener tank where the sludge is thickened at the bottom of the tank. The

thickened sludge from the thickener is pumped to centrifugal hydro extractor for dewatering the sludge.

The dewatered sludge is transformed into a cake form.

Tests Performed at the Factory:

At present simple measurement of pH, Temperature (°C) and Temperature are performed on site using

hand held instruments and BOD tests are performed at the Fabric lab deep section through BOD sensor

meter. The advantage of these instruments does not need to be taken away and also results are obtained

immediately in field. At present we need a Multimeter to measure DO, TDS and TSS on site.

Table-03: Chemical Consumption in March and April, 2015 with Chemical Price/Kg at ETP_IAL

Sl. No. Chemicals for Waste Water

Treatment March_2015 April_2015 Price/Kg

1 Lime Powder (Kg) 14800 15020 9.25

2 Ferrous Sulfate (Kg) 17494 18000 17.5

3 Polyelectrolyte (Kg) 44.5 59 260

4 Hydrochloric Acid (L) 1392 1009 14.5

5 Bio-formula (Kg) 7.25 7.5 9950

Table-04: Chemical Cost in March and April, 2015 at ETP_IAL

Month March_2015 April_2015

Total Chemical Cost Tk. 546936.50 Tk. 558530.50

Total Flow Of Water 38678 m³ 39648 m³

Chemical Cost/M³ Tk. 14.14 Tk. 14.09

Flow of Waste Water/Hr 55.57 m³ 56.97 m³

Figure-02: Schematic Diagram of Proposed Zero Effluent Discharge Plant at IAL

Waste Water

ETP Treated

Water

Filtration

(Ultra & Nano)

Dyeing & Surface

Treatment Process

Rain water

Harvesting

Collection &

Screening

Cooling Return

(Dyeing)

Powder as

solid waste

Management

Spray

Dryer Unit

(10%)

Mechanical

Evaporation

System 20%

Softener

Process

Water Reserve Tank

(275M3)

Toilet Flashing, Car

Washing, Floor Washing

and Gardening

Reverse Osmosis

Plant

70% Recover

Existing Machineries List of ETP_IAL

A. Equalization Tank Section

1. Air Compressor for Aeration and Mixing

a. Number of Units: 01

b. Type: Screw type

c. Capacity: 2.2 m3/min

d. Max. Pressure: 10 Bar

e. Power: 18.5 kW

f. RPM: 2900

2. Effluent Transfer Pump


b. Pump Flow Rate: 75 m3/hr

c. Power: 5.5 kW

d. RPM: 2900

B. Bio-Reactor Tank Section

1. Air Blower


b. Type: 3-Phase Induction type

c. Power: 3.0 kW

d. RPM: 2820

2. Effluent Transfer Pump-01



c. Power: 5.5 kW

d. RPM: 2900




c. Power: 4.5 kW

d. RPM: 2890




c. Power: 3.7 kW

d. RPM: 2900

C. Chemical Mixing Tank Section

1. Flash Mixture Motor for Chemical Mixing


b. Type: 3-Phase Induction Type

c. Power: 0.75 kW

d. RPM: 1050

2. Flocculation Mixture Motor for Chemical Mixing



c. Power: 1.5 kW

d. RPM: 1450

D. Filter Feed Pump Section

1. Filter Feed Pump for Single and Dual Media Filter


b. Type: Centrifugal Volute Type Casing

c. Pump Flow Rate: 75 m3/hr

d. Power: 15 kW

e. RPM: 2900

E. Sludge Sump, Sludge Thickener Tank and Hydro Extractor Section

1. Sludge Transfer Pump-01


b. Type: Centrifugal Type Mud Pump

c. Power: 1.5 kW

d. RPM: 2900

2. Sludge Transfer Pump-02


b. Type: Screw Conveyed Rotary Type Pump

c. Power: 1.5 kW

d. RPM: 1450

3. Sludge Thickener Motor



c. Power: 3.75 kW

d. RPM: 2900

4. Hydro Extractor Motor



c. Power: 3.75 kW

d. RPM: 2900

Environmental Clearance Certificate (ECC) Renewal from Department of

Environment (DoE)

Forward Application for the ECC Renewal is given to-

Deputy Director

Department of Environment

Gazipur zonal office

Gazipur

House#6, Ward#9, Noljani, Chandora, Joydebpur, Gazipur

Documents needed with the Forward Application of ECC Renewal-

1. Application for the Environmental clearance certificate (ECC) renewal

2. Sonali Bank Challan Copy of About Tk. 30000

3. Income Tax certificate

4. Trade license copy from the local govt. institute

5. Last ECC renewal copy

6. Investment board registration copy

7. Last Analysis sheet of waste water treatment of ETP outflow of DoE

a. DoE analysis sheet

b. BUET analysis sheet

Collection and Analysis Report of ETP Treated Water Outflow from DoE

Forward Application for the Collection and Analysis of ETP Treated Water Outflow is given to-

Director Laboratory

Department of Environment

Dhaka Division

E-16, Agargaon

Sher-E-Bangla Nogor, Dhaka-1207

Documents needed for with the Forward Application of ETP Treated Water Outflow Collection

and Analysis of -

1. Forwarding Application for ETP Treated Water Outflow Collection and Analysis

2. Sonali Bank Challan Copy of About Tk. 5600

Present Problems in Our ETP

1. Instruments for Parameter Measurement Shortage

2. Equalization and Bio-Reactor Tanks Volume

3. Civil Drain for Treated Water Discharge

4. Sludge Drainage with Treated Water

5. Centrifugal Hydro Extractor

Graphs from Analysis Sheets of ETP Treated Water Outflow from DoE with Relevant Date:

Graphs from Analysis Sheets of ETP Treated Water Outflow from A. N. M. Hamidul Kabir of the

Department of App. Chemistry and Chemical Eng. Of Dhaka University with Relevant Date:

Table-05: Comparison Between ETP_IAL and ETP_SETL

Sections of ETP ETP_IAL ETP_SETL

ETP Capacity of Water 75 M3/Hr 60 M

3/Hr

Current Flow of Water 55-60 M3/Hr 50~55 M

3/Hr

Inlet Temperature (°C) 37~45 °C 45~48 °C

Treatment Process Biological than Chemical Chemical than Biological

Equalization Tank Separate Tank for Dyeing and

Washing Waste Water

Single Tank for Dyeing and

Washing Waste Water

Bio-Reactor Tank Available after Equalization

Tanks Available after Tube Settler

Tube Settler Number of Units-04

Didn’t Overflowed

Number of Units-02

Sometime Overflowed

Chemical Dosing Minimum More than IAL

Filtering Available and Operated

Properly

Available and but didn’t

Operated Properly

Sludge Handling

Properly Handling but

Sometimes Drained with

Treated Water

Drained into Nearest Pond

Instruments for Measuring

Parameters

pH, DO meter, BOD meter &

Temperature can be measured

Only pH & Temperature can

be measured

Discharge Water Color Colorless Slightly Brownish

Chemical Cost/M3 Tk. 14.11

Figure-03: ETP Drawings of IAL and SETL