Reclaimed Wastewater For Reuse
Cooling Tower Make up Water
In the planning and implementation of water reclamation and reuse, the reclaimed water application will usually govern the wastewater treatment needed to protect public health and the environment, and the degree of reliability required for the treatment processes and operations. The seven principal reuses are listed below:
- Agricultural irrigation, Crop Irrigation and Commercial nurseries.
Issues: Surface and Ground water contamination (if not managed); Marketability of Crops and Public Acceptabilty. - Landscape Irrigation, Parks, School Yards, Golf Courses, Residential, etc.
Issues: Effect of Water Quality on Soils and Crops, Public Health Concerns, - Industrial Recycling and reuse, Cooling Water, Boiler Feed, Process Water and Construction.
Issues: Scaling, Corrosion, Biological Growth and Fouling; Aerosol Transmission of Pathogens (in Cooling water); - Groundwater Recharge and replenishment, Saltwater intrusion and Subsidence control.
Issues: Possible Contamination of Ground Water; Organic Chemicals and their toxicological effects; Total Dissolved Solids, Nitrates and Pathogens in reclaimed water. - Recreational and environmental uses.
Issues: Health Concerns related to presence of bacteria and viruses; Eutrophication; Toxicity to acquatic life. - Nonpotable urban uses, Fire Protection, Air Conditioning and Toilet Flushing
Issues: Public Health concern about pathogens, transmitted by aerosol, effect of scaling, corrosion, biological growth and fouling. - Potable reuse, Blending in Water supply.
Issues: Constituents in reclaimed water, especially traces of organic chemicals and their toxicological effects; aesthetics and public acceptance; Health concerns.
We are concerned with the use of reclaimed water for reuse in Industrial Activities, specifically for make up water in Cooling Towers; which is the predominant industrial water reuse and creates the single largest demand for water in many industries. Industrial uses vary greatly and to provide adequate water quality. Additional treatment is often required, beyond conventional secondary wastewater treatment.
The goal of essentially virus free reclaimed water (i.e. disinfected tertiary) is contained in the California Water Recycling Criteria.
Level of |
Types of Reuse |
Reclaimed Water Quality |
Reclaimed water Monitoring |
Setback Distances |
| Disinfected Tertiary |
Urban Reuse, Food Crop |
pH = 6 – 9 BOD5 < 10 mg/l Turb. < 2 NTU E. Coli = none Res. Cl2 > 1 mg/l |
pH – Weekly BOD – Weekly Turb. – cont E. Coli – Daily Res. Cl2 – cont |
15 m (50 ft.) to potable water supply wells. |
| General Use | Conditions in which use is Allowed | |||
| Disinfected Tertiary Reclaimed Water |
Disinfected Secondary 2.2 Reclaimed Water |
Disinfected Secondary 23 Reclaimed Water |
Undisinfected Secondary Reclaimed Water |
|
All water uses other than potable, food preparation or ground water recharge. |
Allowed | Not Allowed | Not Allowed | Not Allowed |
| Irrigation of Parks, Play Grounds, Residential Yards |
Spray Drip or Surface |
Not Allowed | Not Allowed | Not Allowed |
| Restricted Golf Course, cemeteries | Spray Drip or Surface |
Spray Drip or Surface |
Spray Drip or Surface |
Not Allowed |
| Non Edible Vegetation, Ornamental Plants | Spray Drip or Surface |
Spray Drip or Surface |
Spray Drip or Surface |
Not Allowed |
| All Food Crops | Spray Drip or Surface |
Not Allowed | Not Allowed | Not Allowed |
| Flushing Toilets | Allowed | Not Allowed | Not Allowed | Not Allowed |
| Air Conditioning & Indl. Cooling, using Cooling Towers | Allowed | Not Allowed | Not Allowed | Not Allowed |
| Indl. Cooling not using feature creating aerosols or other mist | Allowed | Allowed | Allowed | Not Allowed |
(See California Code of Regulations, Title 22, Divn. 4, Chapter 3 Water Recycling Criteria, Sections 60301 et seq., Dec. 2, 2000)