Wastewater of industrial laundry
Thien, Pham (2020)
2020
All rights reserved. This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-2020060115857
https://urn.fi/URN:NBN:fi:amk-2020060115857
Tiivistelmä
Laundry wastewater contains a high amount of pollutants that lead to negative impacts on the environment. This thesis aimed to study the wastewater management at industrial laundries. Sources, properties together with impacts of laundry wastewater were represented, and consecutively, wastewater treatment technologies were described and discussed. The data was collected from the literature.
Industrial laundries generally provide both water washing and dry cleaning services to customers. As water washing is the most commonly applied method, the majority of laundry wastewater is generated from this process. Separated water from dry-cleaning also enter the same wastewater streams of other processes. Typical characteristics of laundry wastewater includes an alkaline nature (pH 9,5-11) and relatively high pollutant parameters such as total suspended solids, biological oxygen demand or total organic carbon. These impurities are originated and characterised by washing chemicals and laundered textiles. The concentration and types of pollutants in laundry wastewater is uncertain and varied case by case. Severe effects of laundry wastewater on the treatment process, receiving water body and human health were indicated.
Most of laundry wastewater is pre-treated on-site before being released to the public sewage system or a wastewater treatment plant. Treatment technologies are selected and operated depending on regional regulation and characteristics of wastewater. Preliminary treatment techniques such as screening, flow equalisation, oil/water separation are employed to eliminate gross pollutants (sand, large particles). More advanced methods are utilised to remove suspended solids, heavy metals and other remaining pollutants, such as dissolved air flotation, ultrafiltration.
Stricter standards, together with the continuous increase in fee of water and discharging wastewater, forced industrial laundries to reuse or recycle processed water, by implementing advanced techniques. However, along with working efficiency, an affordable operation fee is also considered as one of the priorities in the investment of new treatment technologies.
Industrial laundries generally provide both water washing and dry cleaning services to customers. As water washing is the most commonly applied method, the majority of laundry wastewater is generated from this process. Separated water from dry-cleaning also enter the same wastewater streams of other processes. Typical characteristics of laundry wastewater includes an alkaline nature (pH 9,5-11) and relatively high pollutant parameters such as total suspended solids, biological oxygen demand or total organic carbon. These impurities are originated and characterised by washing chemicals and laundered textiles. The concentration and types of pollutants in laundry wastewater is uncertain and varied case by case. Severe effects of laundry wastewater on the treatment process, receiving water body and human health were indicated.
Most of laundry wastewater is pre-treated on-site before being released to the public sewage system or a wastewater treatment plant. Treatment technologies are selected and operated depending on regional regulation and characteristics of wastewater. Preliminary treatment techniques such as screening, flow equalisation, oil/water separation are employed to eliminate gross pollutants (sand, large particles). More advanced methods are utilised to remove suspended solids, heavy metals and other remaining pollutants, such as dissolved air flotation, ultrafiltration.
Stricter standards, together with the continuous increase in fee of water and discharging wastewater, forced industrial laundries to reuse or recycle processed water, by implementing advanced techniques. However, along with working efficiency, an affordable operation fee is also considered as one of the priorities in the investment of new treatment technologies.