Tackling the persistent issue of water scarcity in the capital

Tackling the persistent issue of water scarcity in the capital

It has been over a decade that the majority of residents in the capital have been severely affected by water scarcity. In an unbelievable fashion, the load shedding seems to have been cured yet the shortage of water is an ongoing issue. Even though the groundwork for the future is currently being laid in the form of pipelines for the Melamchi water project, sitting idly with the hope of the project solving all our water problems would be foolish. For the denizens of the valley, groundwater extracted through digging wells and boring, alongside water purchased through tankers, have remained popular alternatives. At this time when demand for water greatly exceeds supply, we explore below a solution in the form of reusing water from our homes for non potable purposes.

Analogous to rain water harvesting, where we collect rainwater that would otherwise runoff into our the drains, grey water harvesting is a technique where we redirect and reuse water from our household use such as laundry, kitchen sinks, bathroom sinks and showers. Water from our toilets that end up in sewage, however, do not fall under grey water. That is, grey water doesn’t include the water that is contaminated with fecal matter.

Treatment
Although water sources for grey water are expected to be free of fecal matter, that is not entirely true. A little bit of pathogens and fecal matter do enter the grey water system through shower residue or even kitchen sinks. Another thing to worry about is the level of chemicals in detergents, soaps and other cleansing agents. There are however several ways and multiple levels of treatments -- aerobic pre-treatment, anaerobic to aerobic pre-treatment, gravity or pressure leaching, using soil bed, etc --- to remove solid particles and even reduces chemical adulteration.

Applications

Flush: One of the most prominent, uses of grey water is flushing. The flushing units can be connected to the grey water reservoir or individual bathroom sinks can be redirected towards the flush tank.

Irrigation: There is room for wider application in irrigation if a few precautions are taken. Use of water with high chemical concentration should be avoided. This can be ensured by using the right kind of soaps and detergents. In addition, it is recommended that grey water is used only parts of the plant that will not be consumed later.

Wetlands: If there is enough surplus grey water, it can be used to create wetlands with plants

Washing: Cleaning floors and even cars is possible through grey water but this level of reuse requires the grey water to be well treated through several filtration and purification processes to the point that its toxicities are marginalized.

Good practices

  1. Don’t Stock: It isn’t good to store grey water due to its lack of purity. Ideally a day and in worse case, the water is to be let go within the next day. Overflow systems can be devised to let to of excess grey water into the drainage

  2. Reduce direct contact: Especially while irrigating, let the water drip and seep through the soil rather than creating a runoff

  3. Manage your systems: Based on the need, your systems can have pumps, several compartments and delivery channels. Try to keep them simple but also use the right level of treatment for ambitious use.


Grey water harvesting is a technique where we redirect and reuse water from our household use such as laundry, kitchen sinks, bathroom sinks and showers.

Grey water doesn’t include the water that is contaminated with fecal matter.