Using treated water for aquifer recharge of groundwater presents a wide spectrum of technical and health challenges. A major consideration is the possible presence of chemical and microbiological agents in the source water that could be hazardous to human health and to the environment. Concerns about hazardous agents in the water apply particularly to potable reuse. Although non-potable uses such as irrigation can result in human exposure to hazardous agents, there is less potential for exposure and the risks are therefore significantly lower.

In the present study, the sampling and observation results clearly indicate that the injection of the treated water in the aquifer system improves the groundwater quality and it may not have any discernible risk and harmful impacts for the aquifer system as well to the human health. A summarized review of the study is given in the case study.
The concept of treated water injection is becoming widely accepted and adopted by many countries especially those experiencing water shortages and saline water intrusion problems (Metcalf & Eddy, 2003, Toze, 2006; Fytili and Zabaniotou, 2007). Injection of treated water effluents can significantly reduce or completely remove the impact of these effluents on receiving environments. Additionally, the injection of treated waters may reduce the amount of water that needs to be extracted from environmental water sources. However, due to health and safety concerns, a careful study is required on the same.

Over ten years of treated water injection by SSDC (Currently NDS) into the quaternary rocks and the Adawnib formation aquifer has demonstrated that it has positively impacted the aquifer as evidenced by the increase in prevailing groundwater level. The historic groundwater level contours along with the current groundwater level contours results clearly indicates gradual increases in the groundwater level in the aquifer system, especially at the down gradient side of approximately 1.0 to 2.0 km distant from the Arabian Sea shore along injection strip (where the saline water intrusion possibilities are more).

Also, EC (Salinity) of the groundwater wells is shown to decrease in the injection area. From the TDS contour map , it is clearly evident that in and around the injection strip, groundwater TDS value is ≤ 2000 mg/L, whereas the outside of the injection strip the groundwater TDS value is > 2000 mg/L. Hence the results signify that due to injection of treated water, the salinity level gradually decreased in the aquifer system and therefore the actual objective of the injection of treated sewage effluent water in the aquifer was to stave off increasing groundwater salinities along the coastline resulting from seawater intrusion which was recommended in Dames & Moore 1993 report and the Groundwater Pollution Protection Master Plan (GWPPMP) prepared by Mott MacDonald (1999) is achieved by SSDC (Currently NDS).