Greywater recycling system is any system which can be used for greywater treatment, by improving the quality of greywater to such a level that allows it to be reused effectively. This article discusses greywater recycling system meaning, components, types and conditions, as outlined below;
Greywater Recycling System Meaning: 4 Ways to Define Greywater Recycling System
The definition above portrays greywater recycling system as a tool used in greywater management. Below is yet another greywater meaning, which portrays the concept from the perspective of sustainable development;
A greywater recycling system is a water conservation facility used to facilitate sustainability and mitigate resource depletion in the handling of water resources, through the collection, treatment and reuse of domestic wastewater.
The use of greywater recycling systems promotes circular economy by preventing water and energy waste. Through enhanced energy conservation, these systems mitigate various forms of environmental degradation, such as climate change.
Some components of the system are mentioned below in another greywater recycling system meaning;
Greywater recycling system is a conservative system comprising of conduits, filters, bioreactors, reverse osmosis membranes, and storage vessels that work together to prevent the wastage of energy and water resources by treating domestic wastewater.
Lastly, the greywater recycling meaning is outlined on the basis of the process/steps involved in the use of such systems;
Greywater recycling system is a system used for collection, treatment and storage of domestic wastewater.
Components of a Greywater Recycling System
Components of a greywater recycling system are; pre-filter, buffer tank, bioreactor, aerator, membrane filter, storage tank, and conduits.
1). Prefilter (as one of the Components of a Greywater Recycling System)
This component is used for pretreatment, namely by filtration of the greywater as it is introduced into the system.
It is usually a simple filter bed or membrane, which performs a preliminary removal of the largest insoluble contaminants, to reduce the burden on the subsequent filter(s) and increase the efficiency of the entire system.
2). Buffer Tank
The buffer tank is used for greywater collection.
It reserves wastewater for treatment while the holding capacity of the system is fully utilized.
3). Bioreactor (as one of the Components of a Greywater Recycling System)
The bioreactor is not always present or used in a GWR system.
Its role is that of biological treatment, which is usually by anaerobic digestion.
Bioreactors are needed in cases where the organic content of greywater is significant, and/or where there is need to achieve a high level of purity at the end of the treatment process.
As the name implies, the aerator acts as an inlet for air or oxygen into the system.
Aeration helps to prevent unwanted biochemical processes like putrefaction from occurring. The aerator may also occur as a separate vessel or tank, into which greywater is pumped.
5). Membrane Filter (as one of the Components of a Greywater Recycling System)
The membrane filter works alongside the pre-filter, to remove insoluble contaminants from greywater through filtration.
It could occur as part of an inbuilt reverse osmosis unit, that performs ultra filtration with the application of pressure .
Generally, water passing through the membrane filter is significantly cleaner.
In some systems, subsequent filters after the pre-filter are arranged as a multistage apparatus that allows for multiple filtration phases and higher purity.
Reverse osmosis is rarely used in greywater systems, due to its reliance on energy. In its absence, a simple filter or sequence of filter beds may be used.
6). Storage Tank
As the name implies, this component is used to collect and store treated greywater.
The size or capacity of storage tank depends on the scale of treatment. Pipes are usually connected to the tank, for distribution of the water to its points of use.
7). Conduit(s) (as one of the Components of a Greywater Recycling System)
Conduits or pipes serve as flow passages or carriers, for water through the system.
They usually traverse the entire system, linking all components to the inlet and outlet.
Types of Grey Water Systems
Types of greywater systems are; simple, complex, gravity-driven, pressure-driven, diversion-only, diversion/filtration, and diversion/treatment systems.
They are categorized based on degree of complexity, water flow dynamics, and mode of operation.
Conditions of Greywater Recycling System Usage
The conditions of usage of greywater recycling systems are; residential, industrial and commercial.
Greywater recycling system is a group of integrated components which are used to collect, treat and distribute domestic wastewater.
Components or parts of a greywater recycling system are;
2. Buffer Tank
5. Membrane Filter
6. Storage Tank
Types of greywater systems are;
Conditions of greywater recycling system usage are;
1). Oteng-Peprah, M.; Acheampong, M. A.; deVries, N. K. (2018). “Greywater Characteristics, Treatment Systems, Reuse Strategies and User Perception—a Review.” Water Air and Soil Pollution 229(8). Available at: https://doi.org/10.1007/s11270-018-3909-8. (Accessed 21 October 2022).
2). Ozaki, H.; Sharma, K.; Saktaywin, W.; Wang, D.; Yu, Y. (2000). “Application of ultra low pressure reverse osmosis (ULPRO) membrane to water and wastewater.” Water Science & Technology 42(12):123-135. Available at: https://doi.org/10.2166/wst.2000.0255. (Accessed 21 October 2022).