The Importance of a Wastewater Treatment Plant in Erbil City with Focus on Water Reuse

Introduction

Water covers most of the earth’s surface. From that portion of water, only a very small quantity of it can be classified as freshwater. The rest of the water on the surface of the planet is saline. Freshwater is the most valuable resource on earth which can be acquired from two main sources: ground water and surface water. From which ground water is preferred as it is less likely to be contaminated due to it naturally being protected from the outside environment and its filtration by the rocks and soil. Freshwater is used by the residential, agricultural, industrial, and commercial sectors and as a byproduct wastewater is produced.

The problems of unchecked water consumption

As the surface water is contaminated by pollution, it is more expensive to treat. In contrast, ground water extensive extraction, whereby output rate is greater than the input from the environment, eventually leads to water scarcity as well as ground settlement, sudden sinking of earths surface (due to the negative affects on the soil condition), and sandstorms.

The Erbil wastewater is discharged into the environment without any treatment. This pollutes the surface water, which is the main source of drinking water, indicating that the resources are wasted. The agricultural and industrial sectors are not strictly restricted from using ground and surface water in Erbil, and in some cases, they excessively abstract the water resources. Thus, excessive extraction of groundwater may result in limiting the city’s water resources to a great degree by putting them into water scarcity.

Moreover, it has been reported that the untreated wastewater has been directly used by some farmers to grow their vegetation due to the richness of the raw sewage. However, this will cause severe health problems as the impurities in the wastewater can be found in the food chain.

Water supply and distribution of Erbil City

Erbil City drives its water supply from the greater and lesser Zab rivers (a surface water source) which is then treated in Ifraz Treatment Plant before being distributed to the city. After the freshwater has been used, it is transformed into black water and grey water. The black water is either dumped in designated areas around the city, or supplied to the agricultural sector, and is discharged into an underground channel that is connected to the channels of Qatawi and Arab Kandi which are linked to the wastewater discharge points of the eastern and western parts of the city, respectively. The channels converge on the western side of the city at Turaq, and then follow the path from Kani Qrzhala until they reach the downstream of the Greater Zab River.

The wastewater does not undergo any preliminary treatment prior to its discharge into the river. It only undergoes a natural treatment that involves sunlight exposure, environmental aeration, and dilution with the Zab River.

Wastewater

Wastewater, if left untreated, is a source of pollution as it contains nutrients, bacterial, and organic pollutants that are harmful to both the environment as well as us humans. On the other hand, the establishment of a wastewater treatment plant (WWTP) does not only drastically reduce pollution but it also provides a means to reuse the water and the precious resources that otherwise will go to waste. Approximately 23,000,000 liters of wastewater is produced per day in Erbil City which other than a natural treatment that involves sunlight exposure, environmental aeration, and dilution does not get treated at all.

Wastewater treatment plants and its benefits

The purpose of WWTP is to treat raw sewage prior to its discharge to the environment. This in turn will eliminate the public health threat and environmental detrimental affects sourcing from surface water bodies by the removal of the pollutants. It is important to note that this is a conventional treatment as the wastewater is not suited for agricultural or industrial use; it is required to further treat the wastewater in respect to the sector's specific standards before usage, whether it is for the energy or industrial sector, agricultural sector, surface water storage and augmentation, managed aquifer recharge through water injection, or for potable water distribution. The reuse of water in this manner affectively slows down the extraction process by decreasing the risk of water scarcity to a substantial extent.

After the wastewater is disinfected, it can finally be discharged as an effluent into the downstream. This way, the discharged treated wastewater will not cause any damage to the properties of the water downstream and will not add to the pollution.

In a WWTP, wastewater goes through three levels of treatment: pre- treatment/primary treatment, secondary treatment, and advanced/tertiary treatment. The WWTP will result in several biproducts that if processed (depending on the availability of advanced treatment) will provide recycled material furthering depollution but as of now it is too expensive to be a viable option for a developing country. If advanced treatment is carried out, the sludge can be processed into fertilizers and biogas for agricultural use and electricity production respectively. There are many other products that can be extracted from the ruminants of the treated wastewater such as tissue, toilet paper, bioethanol, etc.

Advanced treatments

In order to reduce both groundwater and surface water pollution in Erbil city, an advanced WWTP should be constructed, which will reduce the dependency of both the agricultural and industrial sectors on main water resources through the water reuse process that it is employed for surface water storage and augmentation, and groundwater recharge. This can be made possible through advanced treatment. There are four major technologies for advanced treatment: microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), and Reverse Osmosis (RO). A MF unit can be constructed in the WWTP that comes after various combination of techniques that can be applied to facilitate the process of reused water depending on the end use. MF is the most sensible for the KRG region as it’s cost requirement is low due to it being a low-pressure filtration. It has a high removal efficiency as it is capable of completely removing bacteria, asbestos, and fat globules. This method of advanced treatment could play a vital role in the water reclamation from Erbil municipal wastewater.

Wastewater Treatment's Role in Reducing Dust Storms in Erbil

Dust storms are caused by strong winds that blow loose dirt and sand particles from the ground into the air which result in the formations of dense clouds of dust. These storms occur in arid or semi-arid regions where the soil is dry and loose. The Construction of a WWTP can potentially contribute to stabilizing soil moisture levels through injecting the treated wastewater into the soil, which will help in the retention of its moisture content. Wastewater can be treated to fit into the standards of water-injection. On that basis, it can be injected into the ground which will replenish the groundwater aquifers. Aquifer recharge provides a consistent source of moisture to the soil. The moisture aids in improving the structure and stability of the soil. It facilitates for a better aggregation of soil particles, which reduces erosion caused by the wind. Stable soil is less prone to be eroded and transported as dust during windy conditions.

Addressing Erbil's Water Challenges

It is inarguable that water is the most essential resource for sustenance and development of any city. Erbil City utilizes water to support its agricultural sector, preserve its industrial sector, and meet the needs of the residential sector. However, the overuse of water, along with low water supply and fear of droughts, is a very prevalent threat to the KRG. The Erbil wastewater is discharged into the environment without any treatment. This pollutes the surface water, which is the main source of drinking water and further solidifying that the resources are wasted. The excessive extraction of groundwater puts the city at risk of water scarcity and the use of untreated wastewater by the agricultural sector puts the general public at a health risk. These issues can all be addressed by implementing a proper wastewater treatment plant. Treating wastewater in this manner will reduce the amount of water used by the city, limit water pollution, and diminish the public health risk by providing cleaner water.