Textile Wastewater Treatment

Presented by Faraz NazarB.E. (Civil), M.E. (Environmental)Design Engr. (Water Supply, Sanitation, Wastewater Treatment)Engineering Consultants Intl. Pvt. Ltd.

Presentation on

BACAKGROUND

Programme For Industrial Sustainable Development (PISD)

PISD is a programme to enable the major industrial sectors of Pakistan to comply with the national and international environmental requirements and to adopt better energy efficiency practices

Initiated by Cleaner Production Institute (CPI) with technical assistance from the Embassy Of Kingdom Of Netherlands (EKN) on July 01, 2007

The programme initially aims to serve the sugar, pulp & paper, textile processing, and leather sectors of Pakistan.

The specific objective of PISD is to enable major industrial sectors of Pakistan to

comply with national and international environmental requirements and to adopt best energy efficiency practices

The Programme focuses on energy efficiency, cleaner technologies, wastewater treatment plants, environmental management systems, and social corporate

responsibility.

Training and Human Resource Development

Training of industry personnel on Cleaner Production Technologies, Energy Efficiency, Wastewater Treatment Technologies, Environmental Management System (EMS) and ISO 14001 Certification.

Cleaner Technologies and Energy Efficiency:

Integrated environmental & energy audits and action plans.

Implementation of Cleaner Production Technologies.

Implementation of Energy Efficient Technologies.

Environment and energy reports.

Consultancy Services for Wastewater Treatment Plants It deals with the consultancy services regarding wastewater treatment plants design and implementation.

Environmental Management System implementation and ISO14001 Certification

Textile industry of Pakistan

In 1947 when Pakistan came into being, two textile mills were established in the country as a colonial heritage. Since the independence, however,

the Pakistani textile industry has played a crucial role in the country’s industrial development.

Today, textile and clothing industry is the backbone of Pakistan’s economy. Its cotton based textiles contribute over 65% to the total exports, 46% of the total manufacturing and provides 38% manufacturing labour force. The availability of cotton as basic raw material and cheap labour has played the principal role in the growth of Pakistan’s textile and clothing industry.

It has an overall integrated structure with an important indigenous cotton crop, increasing man-Made Fibre production, large spinning, weaving,

and knitting, dyeing/printing and finishing capacities as well as expanding garment and home textile industries.

Structure of Textile industry of Pakistan:

IMPACTS OF TEXTLE WASTEWATER DISCHARGE TO ENVIRONMENT

Textile processing generates many waste streams, including liquid, gaseous and solid wastes, some of which may be hazardous.

The nature of the waste generated depends on the type of textile facility, the processes and technologies being operated, and the types of fibers and chemicals used.

The overview on the amounts of waste generated within the textile processes are summarized on next slide.

Sources of pollution in textile manufacturing (NIIR Board, 2003b)

Sources of pollution in textile manufacturing (NIIR Board, 2003b)

POLLUTANTS IN TEXTILE WASTEWATER

Polluting matter in textile wastewater

Floating substances

Suspended solids

Dissolved substances

Biological matter

The floating substances, such as oils, grease, foam, insoluble matter, which are more lighter than water.

The suspended solids include insoluble matters with density similar to or heavier than water, in suspension.

In case of dissolved substances, such as acid and basic substances, heavy metals, pesticides, cyanides and other toxic substances, the water becomes undrinkable and aquatic life can be damaged, with evidence of colour, bad smell and bad taste.

Lastly, biological matters, such as bacteria, algae and fungi can produce bad smells and destroy vegetal and animal life, but in

some conditions they can create an auto depuration process.

Pollutants present in textile wastewater include heat, alkalinity, organic and inorganic matter, heavy metals, sludge, giving a high content of organic matter (COD) and colour problem depending on different forms of dyes, surfactants and textile additives materials used in the process. Textile dyes can be of different kinds, such as; acid, basic, disperse and reactive salts (Several authors have identified as a potential problem the presence of salts in textile dyeing wastewater (EPA, 1996).

Many salts are either used as raw materials or produced as by-products of neutralization or other reactions in textile wet processes.

TEXTILE WASTEWATER CHARACTERISTICS

NATIONAL ENVIRONMENTAL QUALITY STANDARDS FOR TEXTILE EFFLUENT

Under Pakistan Environmental Protection Agency Ordinance. 1983 the Pakistan Environmental Protection Agency with the prior approval of the Pakistan Environmental Protection Council established the National Environmental Quality Standards.

These National Environmental Quality Standards include municipal and liquid industrial effluents, industrial gaseous emissions motor vehicle exhaust and noise.

National Environmental Quality Standards for Municipal and LiquidIndustrial Effluents (mg/L, Unless Otherwise Defined)

TEXTILE WASTEWATER TREATMENT CLASSICATION

Primary Treatment

Basically, physical methods of removing wastewater impurities.

Primary treatments remove and decrease suspended and floating matter and are generally less efficient on colloidal and dissolved matter (except those chemically precipitated).

(Physical removal of floatable & Settleable solids)

Large Floating Objects like Rags and Sticks can be remove by SCREENING

Large Settleable particles like Cinders, Sand and small stones can be settle in Grit chamber

Small particles can be removed from wastewater in Sedimentation Tank.

Secondary Treatment

The secondary treatments remove and decrease colloidal, organic suspended and dissolved matter.

Biological treatment process

Basically, bacterial decomposition of biodegradable organic matter (BCOD)

85% of Organic matter can be remove by use of Bacteria in it.

Some examples are, Activated sludge process, Trickling filters, Anaerobic digestion process

Tertiary Treatment

Tertiary treatments remove and decrease suspended solids, nutritive matter, organic substances, and dissolved solids with a much high efficiency than the one of the secondary treatments.

Heavy Metals, Chemical Compounds and Toxic compounds (i.e. Color)

Metals & Chemical compounds can be removed by advance treatment process such as nitrification or denitrification, filtration, active carbon adsorption, ionic exchange, sulfide and ammonia stripping and reverse osmosis.

Physico-Chemical Processess involved in Tertiary treatment of wastewater.

0.1 MGD RO Package System

Spiral UF system

Chlorine contact chamber where final disinfection occurs before outfall

PROCESS FLOW DIAGRAM FOR TEXTILE WASTEWATER

TREATMENT PLANT