essential to marginal chlorination. The surplus, which is used to control odors and tastes, is later removed by dechlorination. This method is particularly valuable in surface waters with variable ammonia and organic content. Sulfur dioxide reacts with chlorine to form acids that are neutralized by the natural alkalinity of the water. Sulfur dioxide is fed by equipment similar to that used for chlorine feeding. Activated carbon absorbs the excess chlorine, while aeration removes it by dissipating it to the atmosphere.

Water Purification System (3000D)

The 3000D Water Purification System was developed to provide a fully self-contained water purification unit for purifying turbid and bacteria-polluted water. The design of the unit allows for increased efficiency, mobility, and cost effectiveness. The unit provides trouble-flee water purification at the rate of 3,000 gph.

There are four modular components located within a single frame: diesel-powered pump, chlorinator control, filter, and supplies to produce 20,000 gallons of potable water. Subsequent water processing requires only Diatamatious earth, chlorine, and diesel fuel. Each module may be operated independently in or out of the frame by one person.

Figure 9-18. - Breakpoint chlorination curves.