Ozone & AOP for STP Tertiary Treatment

Over the period of time, many different types of sewage treatment plants are designed & installed. All sewage treatment plant uses primary, secondary & tertiary stages in treating domestic, commercial, institutional & industrial sewage water. The core of all treatment is secondary stage where pollutants mainly human fecal are degraded by different types of bacteria & make sewage water environmentally safe. After biological secondary stage the prime role of tertiary stage is disinfection i.e. elimination of carry forward of these bacteria & filtration. For disinfection in most of the sewage treatment plants, chlorine is used in tertiary stage. In many countries & by pollution control agencies use of chlorine in STP is prohibited due to many environmental hazards. Globally Ozone is used in tertiary treatment for bacterial disinfection. In fact many environmentalist, scientists & pollution control boards strongly recommend use of Ozone in tertiary stage of STP.

In urban cities, where source of fresh water is limited it is necessary to reuse treated waste water. In fact in most of commercial establishments it is mandatory to use treated sewage water in flushing, gardening & cooling tower. When any sewage treated waste water is being reclaimed for non-potable use, expected quality of treated water is very high. It is expected to be free for micro-organisms, color, & odor. So in this situation where high quality of STP treated water is expected Ozone technology becomes most effective & efficient.

Increased use of personal body care products, pharmaceutical drugs & many emerging pollutants the sewage water treatment becomes more & more challenging. Advance Oxidation Process [AOP] provides much broader coverage of pollutant spectrum with higher performance. AOP mainly uses Ozone with specific wave length of Ultraviolet radiation to produce hydroxyl [OH-] radicals.

Spantech Engineers offers Laboratory Experimental & pilot plant services to establish the result & efficiency of Ozonation & AOP.

Process Flow Diagram – Retrofitting STP Ozonation

Without any modification, Ozonation can be integrated in existing sewage treatment tertiary stage. Where conventional chlorine contact tank can be used as a Ozone dossing, mixing & contact tank. The diagram shows the most efficient technique of Ozonation for post-secondary disinfection with color & odor reduction. There are few more techniques of Ozone system integration in existing sewage treatment plant, which can be selected as per site conditions.

Process Flow Diagram – New Installation Of STP Ozonation

In case of new construction of STP with Integrated Ozone System [IOS] for tertiary treatment, we recommend the below scheme for the best optimum performance. Here the size of the clarified water tank can be reduced to 1.5 – 2.0 times peak flow. Secondary clarified water first has to be filtered before going to Ozonation, to reduce the load on Ozone dossing. Here we use a special “Charged Active Pressure Filter [CAPF]” to efficiently filter the waste water, and collected in a filtered water cum Ozonation tank. Since Ozone is an micro-flocculent & oxidizes inorganics to precipitation, always use second pass CAPF for absolute clarity. Now the final ozone treated water can be used for all non-potable application like, flushing, gardening, surface cleaning, cooling tower, industrial use & many more.

Questionnaires:

To design & estimate the STP tertiary treatment ozonation few input data are required, and on the basis of the same Ozone dose, capacity, integration point, dossing technique is optimized. One who needs the STP tertiary stage Ozonation can submit available data and for new plant estimated data & mail us at : sales@spantechengineers.com & we will design optimum solution with nominal charges or free of cost. The amount we charge is used for research & development, social cause & donations.