A water filter is a device used to remove debris from water using a fine physical barrier, a chemical process, and/or using a biological process. These filters are mainly used to purify water so that it can be used for irritations, aquariums, swimming pools and of course drinking water. With water purification, all contaminants are removed from raw water sources. Water is produced for a specific reason with a treatment profile to limit the inclusion of specific materials. Generally, water is purified so that it is fit for human consumption. Before being used, the water undergoes a certain number of treatments. First, water is pumped from its source into the holding tank pipes. The water is then filtered by physically removing large debris such as branches, sticks, leaves and trash. They must be removed in order to avoid complications during subsequent purification processes. Water from river banks can also be stored in reservoirs for a few days or months to allow natural biological purification. Many waters rich in hard salts are treated with sodium carbonate to expel calcium carbonate using the common ionic effect. Many waters are also chlorinated to reduce the growth of polluting organisms on pipe reservoirs. Chlorine gas or sodium hypochlorite reacts with organic compounds in water, causing potentially harmful chemical byproducts to form. The trihalomethanes and haloacetic acids that form are both carcinogenic in large quantities. Chlorine also does not kill Gardia and Cryptosporidium. Chlorine dioxide creates excessive amounts of chlorate and chlorite and poses an extreme risk when handling because it is an explosive gas. ......middle of paper......it has very limited capacity to do anything. South Africa is unfortunately short of water and endocrine disruptors are concentrated in our overloaded rivers and are recycled throughout our society. We must prevent the uncontrolled increase in the number of babies born with urogenital anomalies and combat the loss of male fertility. Some of the medications taken today have endocrine disruptor capabilities and hormones, such as estrogen, progesterone, etc., are not effectively removed by current wastewater and water treatment processes, leading to to feminized male animals. What is not known are the effects of antiretroviral drugs entering river systems. The drugs pass through the human body in a partially metabolized form and it is not known whether these partially metabolized antiretrovirals will have a harmful effect on people. (Turton 2009)