Cromaglass Newsletter

With many communities throughout the world approaching or reaching the limits of their available water supplies, water reclamation and reuse has become an attractive option for conserving and extending these supplies. Water reuse may also present communities an opportunity for pollution abatement when it replaces effluent discharge to sensitive surface waters.

The U. S. Environmental Protection Agency, in recognition of the importance of water reuse, has published a manual titled "Guidelines for Water Reuse." Much of the salient information is reported in this newsletter.

Water reclamation and nonpotable reuse only require conventional water and wastewater treatment technology that is widely practiced and readily available in countries throughout the world. Furthermore, because properly implemented nonpotable reuse does not entail significant health risks, it has generally been accepted and endorsed by the public in the urban and agricultural areas where it has been introduced.

Water reclamation for nonpotable reuse has been adopted in the United States and elsewhere without the benefit of national or international guidelines or standards. However, in recent years, many states in the U.S. have adopted standards or guidelines, and the World Health Organization (WHO) has published guidelines for reuse for agricultural irrigation.

Standards are not proposed by the U.S. Environmental Protection Agency (EPA) or the U.S. Agency for International Development (AID). In the U.S., water reclamation and reuse standards are the responsibility of state agencies. The purpose of EPA's manual is to present guidelines for authorities in areas where standards do not exist.

The use of reclaimed water for nonpotable purposes offers the potential for exploiting a "new" resource that can be substituted for existing resources. By "source substitution" - an increased population can be served from an existing potable water source.

Many urban residential, commercial, and industrial uses can be satisfied with water of less than potable quality: irrigation of lawns, parks, roadway borders and medians; industrial processing; toilet and urinal flushing; construction; cleansing and maintenance, including vehicle washing; scenic waters and fountains; and environmental and recreational purposes.

While the need for additional water supply has indeed been the impetus for numerous water reclamation and reuse programs in arid and semi-arid areas, many programs in the U.S. are initiated in response to rigorous and costly requirements for effluent discharge to surface waters, particularly the removal of nitrogen and phosphorous. By eliminating effluent discharges for all or even a portion of the year through water reuse, the need for costly advanced wastewater treatment processes may be reduced or avoided. For most nonpotable reuse applications, nutrient removal is unnecessary and actually contraindicated for irrigation.

Demonstrates positioning of Cromaglass Batch Treat System

next to eating facilities and front of building

- no problems with odors or visual contact.

Naturally, a water reuse program can easily serve both water conservation and pollution abatement purposes.

The overriding consideration in developing a reuse system is that the quality of the reclaimed water be appropriate for its intended use.

The most common parameters for which water quality limits are imposed are biochemical oxygen demand (BOD), total suspended solids (TSS), and total or fecal coliform counts. Fecal coliform counts are generally used as indicators to determine the degree of disinfection. A limit on turbidity is usually specified to monitor the performance of the treatment facility's reliability - proof that high quality can be maintained. This was accomplished on Cromaglass recycle/reuse systems through tests of the Ben Franklin Research Program using internationally accepted standards for recycle and reuse of wastewater.

Dr. Melvin C. Zimmerman, the administrator, and his staff reviewed with NSF the protocol to be followed, including inspection of the test site and analytical laboratories. Mr. Michael Gerardi consulted on the project as a wastewater biologist.

Overall, the Ben Franklin Technology Center's evaluation covered a period from September 19, 1995 through May 14, 1996, or eight months.

Cumulative statistics over the program length (though three seasonal changes) provided data results with a mean of 2.84 mg/L BOD₅ and 2.48 mg/L total suspended solids - and total residual coliform toxicity "neither acutely nor chronically toxic (to the ceriodaphnia dubia or the fathead minnow)."*

In general, most states with regulations require a minimum of secondary or biological treatment followed by disinfection prior to restricted urban reuse.

Where specified by regulation, generally limits on BOD range from 5mg/L to 30 mg/L, limits on TSS vary from 5 mg/L to 90 mg/L. For those states that do not specify limitations on BOD or TSS, a percent reduction of contaminant removal is usually established.

Average fecal coliform limits for those states that limit fecal coliform range from non-detectable to 1,000/100 mL, with some states allowing higher single sample fecal coliform limits.

Where water reuse regulations have been developed by many states these regulations vary considerably from state to state. Some states, such as Arizona, California, Florida, and Texas, have developed regulations that strongly encourage water reuse as a water resources conservation strategy. These states have developed comprehensive regulations specifying water quality requirements, treatment processes, or both for the full spectrum of reuse applications. The objective in these states is to derive the maximum resource benefits of the reclaimed water while protecting the environment and public health. Some states have developed water reuse regulations with the primary intent of providing a disposal alternative to discharge to surface waters, also considering the management of reclaimed water as a resource.