What Is A Reclaimed Water?
What Is A Reclaimed Water?
Reclaimed water refers to wastewater treated for reuse. With modern technology, it can be used for various purposes after treatment, depending on the source and delivery method.
Water reclamation refers to the process of converting wastewater from cities or industries into reusable water for various purposes. The types of reuse include irrigation for agriculture, replenishing groundwater and even for household needs like toilet flushing.
This water can be treated to meet drinking water standards, though direct potable reuse is not a widespread practice. The reuse of wastewater helps with sustainable water management and can mitigate the effects of water scarcity and reduce pressure on natural water sources.
The treatment of wastewater for reuse involves several technologies, such as ozonation, reverse osmosis and aerobic treatment, to make sure the processed water is safe. However, the cost of water reclamation can be high in regions with an abundant supply of fresh water.
As water scarcity becomes more pressing, water recycling and reuse are becoming increasingly important, particularly in arid regions and contaminated environments. The Middle East and North Africa region has a high rate of municipal wastewater reuse.
Benefits Of Reclaimed Water
Water/wastewater reuse is an alternative water source that offers substantial economic, social, and environmental benefits, making it a strong incentive for implementing these programs.
For cities and households, increased water availability can be achieved by substituting drinking water with reclaimed water for non-drinking purposes, such as industry, cleaning, irrigation, domestic uses, and toilet flushing.
For the environment, reuse programs reduce nutrient loads to receiving waters, decrease over-abstraction of surface and groundwater, and improve environmental protection through the restoration of streams, wetlands, and ponds.
Reuse programs also lower energy consumption in water production, treatment, and distribution, compared to using deep groundwater resources, water importation, or desalination. In manufacturing, the use of high-quality reclaimed water can reduce costs.
In agriculture, irrigation with treated wastewater can enhance production yields, reduce the ecological footprint, promote socioeconomic benefits, as well as conserve nutrients and reduce the need for artificial fertilizer.
Reusing water instead of freshwater also conserves water resources and can improve natural water cycles when eventually discharged back into the environment.
Applications Of Reclaimed Water
Treated wastewater can serve a variety of purposes beyond just being discarded. Reclaimed water can be used for industrial applications such as cooling towers, in agriculture for irrigation and for the restoration of natural ecosystems like wetlands.
In urban areas, it can be used for things like irrigating public parks, street cleaning, and flushing toilets. In agriculture, it can be used for growing crops, pasturing animals, and greenhouse cultivation. Industries also make use of reclaimed water for processing and cooling purposes.
Recreational uses include golf course irrigation and maintaining recreational impoundments. The environmental benefits of reclaimed water include recharging aquifers and creating wildlife habitats. In some cases, it can even be treated to potable standards for drinking water use.
Distribution Of Reclaimed Water
Reclaimed water that is not safe to drink is typically conveyed via a dual piping system that separates it from potable water pipes. The increasing demand for reclaimed water in cities has led to restrictions on usage, with consumers only allowed to use it on designated days.
Some cities, which previously offered unlimited access at a fixed rate, are now starting to implement a usage-based billing system for reclaimed water.
Treatment Processes Of Reclaimed Water
Wastewater treatment is a process that makes water safe and usable again. There are several technologies used to treat wastewater for reuse including ozonation, ultrafiltration, aerobic treatment, forward osmosis, reverse osmosis and advanced oxidation.
Reclaimed water providers use a combination of these technologies along with constant monitoring to ensure that the processed water is hygienically safe and free from pathogens. In some cases, water-demanding activities may not require high-grade water and thus, wastewater can be reused with little or no treatment.
This is often seen in the domestic environment, where greywater from baths and showers can be used to flush toilets. Municipal wastewater goes through multiple steps, including screening, primary settling, biological treatment, tertiary treatment and disinfection, to ensure it is safe for use.
Wastewater treated to secondary level treatment is usually used for irrigation. A pump station distributes the reclaimed water to various users in the city, such as golf courses, agriculture, cooling towers, and landfills.
Health Aspects Of Reclaimed Water
Reclaimed water, which is treated before being used for recharge of aquifers or surface water, has been deemed safe for appropriate usage.
A study from 2009 found that the water quality of reclaimed, surface and groundwater water was more similar than dissimilar, as the researchers tested for 244 typical constituents in water and found most in the parts per billion and trillion range.
While DEET and caffeine were found in all water types, triclosan was found in higher levels in reclaimed water than in other types of water. Meanwhile, haloacetic acids were present in all types of water, including groundwater.
The report also found that there have been no reported incidents of illness or disease from either chemical contaminants or microbial pathogens.
A study conducted by the National Research Council in 2012 showed that the risk of exposure to certain chemicals and microbial contaminants in drinking reclaimed water is not higher than the risk associated with drinking water treatment systems, and may even be lower.
The report recommends regulatory changes to enhance public health protection and increase public confidence in water reuse.
Environmental Aspects Of Reclaimed Water
Reusing reclaimed water for non-potable purposes conserves fresh water for human consumption. Reclaimed water sometimes contains higher levels of nutrients such as nitrogen, phosphorus, and oxygen, which can aid in plant growth when used for irrigation.
Fresh water is a scarce resource, with only 1% readily available for human consumption, and the rest primarily used for agriculture. Reclaimed water offers an alternative source of water in areas with limited freshwater supplies.
It can be used for a variety of purposes, including street cleaning, irrigation, industrial processes and restoring wetlands, lakes, and river flows. Reclaimed water is a consistent source, unaffected by seasonal changes or droughts.
The use of reclaimed water reduces pollution and benefits the environment by enhancing wetlands and reducing the chances of drought. For example the San Jose/Santa Clara Water Pollution Control Plant implemented a water recycling program to protect local saltwater marshes.
However, there are potential risks associated with using reclaimed water for irrigation, such as contamination of the food chain with pathogens and microcontaminants, soil salinization, and accumulation of harmful substances in the soil and groundwater.
Poor treatment of the water can also lead to excessive growth of vegetation, soil alteration and degradation of groundwater quality.
