Effect of washing method and detergent type on laundry greywater characteristics

Domestic laundry, accounting for 15 to 40 % of total water consumption, contributes significantly to household water consumption, suggesting its potential for non-potable reuse. The effect of washing method (machine vs. manual) and detergent type (liquid vs. powder) on the quantity and quality of laundry greywater was studied in the present study. The influence of washing machine, capacity and detergent usage on water consumption and greywater generation was also studied. A survey conducted in Pune, India on 76 households showed that 30.6 % opt for manual laundry, while 69.4 % use washing machines, with 36.2 % employing fully automatic and 33.2 % semi-automatic machines. Powder and liquid detergents were utilized by 52.5 % and 36.7 % of households, respectively, with 10.8 % using both. Washing machine water consumption correlates positively with capacity, with top-load fully automatic machines using twice as much water as front-load ones. Greywater generation averages 21.9 and 21.9 l per capita per day (lpcd) with liquid and powder detergents in washing machines and 13.9 and 13.4 lpcd in manual laundry. Washing machine greywater was significantly (p