Remove heavy metals with cilantro. Just as pine trees are effective at removing pathogens, so too is cilantro excellent at removing heavy metals from water. Fill a pitcher with water and place a handful of cilantro leaves into the pitcher. Stir the water and let the leaves sit in the water for at least an hour. Remove and discard the cilantro before drinking the water.[11]
While nearly everyone loves the taste from this water filtration system, a few people tested the pH and complained that it wasn’t as alkaline as they hoped for in a system that adds back beneficial minerals. However, the company points out that the pH filter will raise acidity by 1-1.5 levels, so the final pH will depend on the chemistry of the water that you’re starting with. 

While reverse osmosis systems are widely used for industrial and commercial purposes, smaller home units can be purchased and installed under the kitchen sink and dispensed through the faucet. Home RO units typically run on a 3-stage system which includes a carbon filter, RO membrane, and re-mineralizing filter for taste. Some systems can include 5, 7, or even 10 stages. While the additional stages offer extra benefits such as pH level balance and UV filtration, a simple 3-stage system has everything required to produce pure, drinkable water. RO systems require frequent maintenance and replacement of filters in order to keep it functioning properly. Read our article on reverse osmosis systems for home use for a detailed guide on how they work and which brands to use.
In 1904, Allen Hazen showed that the efficiency of a sedimentation process was a function of the particle settling velocity, the flow through the tank and the surface area of tank. Sedimentation tanks are typically designed within a range of overflow rates of 0.5 to 1.0 gallons per minute per square foot (or 1.25 to 2.5 litres per square meter per hour). In general, sedimentation basin efficiency is not a function of detention time or depth of the basin. Although, basin depth must be sufficient so that water currents do not disturb the sludge and settled particle interactions are promoted. As particle concentrations in the settled water increase near the sludge surface on the bottom of the tank, settling velocities can increase due to collisions and agglomeration of particles. Typical detention times for sedimentation vary from 1.5 to 4 hours and basin depths vary from 10 to 15 feet (3 to 4.5 meters).[6]:9.39–9.40[7]:790–1[8]:140–2, 171
Water filtration is probably the most common method of purification for personal consumption, mainly because of its versatility and ease of use. Water filtration systems come in many forms and sizes, some of which are even portable. The most common water filtration systems are integrated with household sinks and refrigerators by connecting to the waterline.
A reverse osmosis system is typically installed under the sink, but you can install it where your water enters the house, so all your water is filtered for contaminants. RO filter cartridges provide the most effective filtration of any water purifiers. The membrane and filters remove up to 99 percent of contaminants such as arsenic, lead, ammonia and chlorine, as well as toxic fluoride, sodium, nitrates and heavy metals. The 6 stage RO filters provide a deep filtering process, leaving you reverse osmosis water, free of sediments and toxins. RO water is perfect for drinking, cooking and making ice.
Membrane filters are widely used for filtering both drinking water and sewage. For drinking water, membrane filters can remove virtually all particles larger than 0.2 μm—including giardia and cryptosporidium. Membrane filters are an effective form of tertiary treatment when it is desired to reuse the water for industry, for limited domestic purposes, or before discharging the water into a river that is used by towns further downstream. They are widely used in industry, particularly for beverage preparation (including bottled water). However no filtration can remove substances that are actually dissolved in the water such as phosphates, nitrates and heavy metal ions.
The remineralization stage is an additional feature of this water purifier. The name itself explains the function of this stage. After passing through the basic 5 stages of filtration the water is treated in the remineralization stage. At this point of purification, some advantageous minerals restored into the water again. The added minerals improve the taste and raise the pH to more alkaline. You will definitely enjoy the fresher tasting mineral water.
As with any other filter type water purification method, careful attention has to be taken to pathogen/virus and chemicals size. During hurricane Katrina a lot of the water was contaminated with petroleum based chemicals from flooded cars. What is removed from the water is dependent on the filter pore size. However, it is difficult to beat the lightweight option that water purification straws and bottles provide for most situations.