Liquid waste management - Types and treatment

LIQUID WASTE
Liquid waste can be defined as such Liquids as wastewater, fats, oils or grease (FOG), used oil, liquids, solids, gases, or sludges and hazardous household liquids. These liquids that are hazardous or potentially harmful to human health or the environment. They can also be discarded commercial products classified as “Liquid Industrial Waste” such as cleaning fluids or pesticides, or the by-products of manufacturing processes. 

Types of Industrial Wastewater

• Inorganic wastewater
• Organic wastewater
• Listed hazardous wastewater
• Industrial wastewater with heavy metals
• Industrial wastewater with organics
• Non-hazardous wastewater
• Oil and water mixtures

Industrial Wastewater Treatment Technologies

• Chemical oxidation and reduction
• Acid/Base neutralization
• Chemical precipitation of metals
• Flocculation
• Filtration
• Carbon adsorption
• Supercritical fluid extraction
• Biological treatment
• Oil/Water separation
• Stabilization through encapsulation

Liquid wastes are not suitable for disposal to any class of landfill because they:

• increase the volume of leachate generated and requiring treatment and/or disposal
• can result in increased odour nuisance
• can reduce the stability of the refuse mass under certain conditions.

Liquid waste encompasses all waste in liquid form, it includes both waste produced as a liquid and waste that has been converted into a liquid for handling. Similarly, it includes both liquid waste that emerges from a single source such as industrial wastes being pumped out through pipes and liquid waste that has no single source such as run-off caused by rainfall. Other common examples of liquid waste include both human and animal excreta plus household wastewater coming from bathing, dishwashing, and a range of other domestic activities.

Liquid waste can be removed by:

• -Containment: In this case, the waste is stored either in barrels or tanks that can be picked up by waste management services
• -Treatment: In this case the liquids are treated before disposal. The treatment technology adopted depends upon the composition of the liquid waste. Organic wastes are composted whereas non-hazardous liquid wastes have their water content extracted.
• -Disposal: The liquid wastes after treatment are either dumped in landfills, incinerated or converted into new products that can be reused.