The document discusses various environmental issues related to wool scouring. It notes that raw wool contains residues from pesticides used on sheep that can pollute waterways if discharged in effluent. It also discusses how different pesticides associate with grease or dirt and are removed to varying degrees during scouring. Land pollution can occur from disposal of grease and sludge by-products. Air pollution is also possible if sludge is incinerated. Overall, the document provides an overview of potential water, land and air pollution risks from the wool scouring process and effluent treatment.

1. ENVIRONMENT ISSUES IN SCOURING OF WOOL R.B.CHAVAN Department of textile technology Indian Institute of Technology Hauz-Khas, New Delhi 110016 E-mail: [email_address]

5. Ectoparasiticides present in raw wool Cyromazine Dicyclanil Difilibenzliron Triflumuron Insect growth regulators (IGRs) Cypermethrin Deltamethrin Fenvalerate Flumethrin Cyhalothrin Synthetic pyrethroids insecticides (SPs Diazinon Propetamphos Chlorfenvinphos Chlorpyriphos Dichlorfenthion Organophosphorous insecticides (OPs) yHexachlorocyclohexane (Imdane) Dieldrin DDT Organochlorine insecticides (OCs)

6. well-studied substances.Endocrine (Blood secreting glands) disrupting capacity Lindane and DDT most toxic (also the most active as pesticide) Hexachlorocyclohexane (also called lindane) hazardous due to their persistence and bioaccumulity. Likely to have long-range effects organochlorines (Ocs)

7. have lower aquatic toxicity than synthetic pyrethroids and are less persistent than organochlorines. Nevertheless they have high human toxicity Organophosphates (Ops) show high aquatic toxicity The synthetic pyrethroid insecticides (SPs)

10. Wool scouring Environment issues Potential for pollution of water The removal of contaminants present on the raw fibre leads to the discharge of an effluent main polluting contributors are:

13. Recent studies have shown that triflumuron (IGR) associates partially with the dirt and partially with the grease. As a result, compared to other lipophilic compounds, a higher proportion of this pesticide is likely to be retained on-site (on the wool fibre and on the recovered wool grease and dirt) and not be discharged in the aqueous effluent

15. Despite these treatments, the removal of pesticides is often incomplete and there is potential for pesticides to enter the aquatic environment when the effluent is discharged The environmental concentrations of ectoparasiticides in the receiving water depend greatly on local circumstances, in particular, the amount of scouring activity concentrated in a given catchment and the dilution available between scouring discharges and the river which receives the treated effluent. The control of the discharge limits at the scouring mills is carried out by comparing with standards.

16. Potential for pollution of land Two main "wastes", grease and sludge, are produced as a consequence of scouring activities (and related effluent treatment). it may be possible to recover from 20 to 40 % of the grease initially present on the raw wool This is to be regarded as a by-product rather than a waste, since it can be sold to lanolin refiners for the production of high-value products in the cosmetic industry However, high levels of pesticides residues in the grease can also be a problem for the lanolin refiners, especially for the production of lanolin-based pharmaceuticals and cosmetics more expensive and sophisticated techniques have to be used to reduce the pesticides to acceptable levels Acid-cracked grease has no market value and has to be landfilled

17. Potential for pollution of land (Contd) The sludge produced as a result of physico-chemical treatment of waste water also contains grease, dirt and the portion of pesticides which are strongly associated with either grease or dirt. Concentrates and sludges from evaporation or membrane filtration may also contain suint. which is mainly potassium chloride and potassium salts of fatty acids. Suint is a by-product which can be used in agriculture

18. Disposal of Concentrate and Sludge • incineration (with heat recovery) Pyrolysis/gasification • brick manufacturing • composting or co-composting with other organic material • landfill The first three sludge disposal routes destroy the organic material in the sludge, including grease and pesticides. The ash from incineration may contain potassium salts, derived from suint, and heavy metals characteristic of the soil on which the sheep producing the wool have grazed. The ash is normally disposed of to landfill

25. Wool preparation before colouring Carbinsing Scouring, Drycleaning Fulling Bleaching

27. Pollution originating from impurities present on the raw material Residues of pesticides used to prevent the sheep becoming infested with external parasites can still be found on scoured wool in amounts, which depend on the efficiency of the scouring process. These are mainly organophosphates (OPs) and synthetic pyrethroid (SPs) insecticides and insect growth regulators (IGRs), detectable residues of organochlorine pesticides (OCs) can be observed. They partition between the fibre and the water according to their stronger or weaker lipophylic character and, as a consequence, traces of these compounds are released in the waste water.

30. Other pollutants of concern that may be found in water effluent from pretreatment activities are: • reducing agents from bleaching treatments and chemical setting of carpet wool yarn (sodium metabisulphite): they contribute to oxygen demand in the waste water • poorly bio-eliminable complexing agents (e.g. EDTA, DTPA, phosphonates) from hydrogen peroxide stabilisers, etc. • insect-resist agents in wool carpet yarn production