LAUNDRY WASTEWATER

Laundry wastewater, a category of greywater, contains various chemical constituents such as soap, suspended solids, oils, perfumes, and other pollutants at high concentrations. This study investigated the prevalence of virulence factors in bacterial isolates obtained from laundry wastewater to highlight their potential health risks. Samples were collected from residential and industrial laundry facilities, and the microbial isolates were analyzed using biochemical, molecular, and phenotypic methods. The total heterotrophic bacterial counts were recorded as 82.25 ± 4.7 CFU/mL × 10⁷ in Laundry Wastewater V and 94.50 ± 6.1 CFU/mL × 10⁷ in Laundry Wastewater W. Twenty-five bacterial isolates which include Staphylococcus aureus, Staphylococcus spp., Escherichia coli, and pseudomonas spp. were characterized. The most frequently isolated bacterium was Staphylococcus aureus [11/25 (44.0%)], followed by Escherichia coli [7/25 (28.0%)], Pseudomonas spp. [4/25 (16.0%)], and Staphylococcus spp. [3/25 (12.0%)]. Virulence factors such as DNase activity, lipase activity, and hemolytic activity were assessed. DNase activity was observed in 40% of the isolates, lipase activity in 52%, and hemolytic activity in 92%. Among Staphylococcus aureus isolates, DNase activity was 45.5%, lipase activity was 54.5%, and hemolytic activity was 100%. Similarly, hemolytic activity was prevalent in all Escherichia coli isolates (100%) and 75% of Pseudomonas spp. isolates. This study highlights the high prevalence of virulence factors in bacterial isolates from laundry wastewater and underscores its potential as a reservoir of pathogenic microorganisms. Untreated discharge of such wastewater poses serious public health and environmental risks. Therefore, it
emphasizes the need for enhanced wastewater treatment systems and further research on the
ecological and epidemiological implications of virulence factors in laundry effluents.

Laundry wastewater, a category of greywater, contains various chemical constituents such as soap, suspended solids, oils, perfumes, and other pollutants at high concentrations. This study investigated the prevalence of virulence factors in bacterial isolates obtained from laundrywastewater to highlight their potential health risks. Samples were collected from residential and industrial laundry facilities, and the microbial isolates were analyzed using biochemical, molecular, and phenotypic methods. The total heterotrophic bacterial counts were recorded as 82.25 ± 4.7 CFU/mL × 10⁷ in Laundry Wastewater V and 94.50 ± 6.1 CFU/mL × 10⁷ in Laundry Wastewater W. Twenty-five bacterial isolates which include Staphylococcus aureus, Staphylococcus spp., Escherichia coli, and Pseudomonas spp. were characterized. The most frequently isolated bacterium was Staphylococcus aureus [11/25 (44.0%)], followed by Escherichia coli [7/25 (28.0%)], Pseudomonas spp. [4/25 (16.0%)], and Staphylococcus spp. [3/25 (12.0%)]. Virulence
factors such as DNase activity, lipase activity, and hemolytic activity were assessed. DNase activity was observed in 40% of the isolates, lipase activity in 52%, and hemolytic activity in 92%. Among Staphylococcus aureus isolates, DNase activity was 45.5%, lipase activity was 54.5%, and hemolytic activity was 100%. Similarly, hemolytic activity was prevalent in all Escherichia coli isolates (100%) and 75% of Pseudomonas spp. isolates. This study highlights the high prevalence of virulence factors in bacterial isolates from laundry wastewater and underscores its potential as a reservoir of pathogenic microorganisms. Untreated discharge of such wastewater poses serious public health and environmental risks. Therefore, it emphasizes the need for enhanced wastewater treatment systems and further research on the ecological and epidemiological implications of virulence factors in laundry effluents.

The contamination of water sources by untreated wastewater poses a serious public health risk due to the spread of pathogenic bacteria, particularly Gram-positive species. This study examined the microbiological properties of wastewater collected from commercial laundry shops in Benin City, Edo State, Nigeria. The research focused on enumerating total heterotrophic bacteria, isolating Gram-positive bacteria, and identifying their species based on morphological and biochemical characteristics. A total of eight (8) wastewater samples were collected in duplicates from two commercial laundry shops, with the samples divided into two categories: wastewater from washing and wastewater from rinsing. Microbial enumeration was performed using the spread plate technique on nutrient agar, while Mannitol salt agar was used for selective screening of Gram-positive bacteria. The bacterial isolates were characterized based on their morphological and biochemical properties using standard microbiological methods. Results revealed that the total heterotrophic bacterial counts were highest in the laundry washing wastewater samples, with values ranging from 102±2.3 × 10⁶ to 81±0.9 × 10⁶ CFU/mL. In contrast, significantly lower bacterial counts were observed in the rinsing wastewater samples, with counts ranging from 48±1.8 × 10⁶ to 25±2.4 × 10⁶ CFU/mL. Additionally, the bacterial counts varied by location, with Laundry Shop 1 recording 68±1.4 × 10⁶ CFU/mL and Laundry Shop 2 showing slightly lower counts at 57±1.6 × 10⁶ CFU/mL. The microbiological assessment of laundry wastewater revealed the presence of diverse bacterial species, with a total of 17 isolates identified and characterized. Staphylococcus aureus was the most prevalent isolate, accounting for 52.9% (9/17) of the total, followed by Staphylococcus spp. (41.2%) and Micrococcus spp. (5.9%). These findings highlight the potential health and environmental risks associated with untreated laundry wastewater, particularly due to the dominance of pathogenic and opportunistic bacteria. The study emphasizes the need for effective wastewater management practices in commercial laundry facilities to mitigate the spread of microbial contaminants. Future research could focus on advanced treatment technologies and their ability to reduce bacterial load in laundry effluent.