G. Fred Lee, PhD, PE, DEE and Anne Jones-Lee, PhD
G. Fred Lee & Associates
El Macero, California

1995

With increased demands being placed on domestic water supplies for expanding populations, increased attention is being given to the use of reclaimed domestic wastewaters for irrigation of golf courses, parks and ornamental shrubbery. There is, however, justifiable concern about the residual pathogenic organisms and hazardous or otherwise deleterious chemicals that are present in domestic wastewaters that are reclaimed by treatment approaches that do not truly disinfect the reclaimed domestic wastewaters for all human pathogenic organisms and for residual organics and other constituents that are typically present in secondarily-treated domestic wastewaters.

At this time, regulatory agencies allow the use of reclaimed domestic wastewaters for ornamental shrubbery, park and golf course irrigation which has only been treated to essentially secondary treatment effluent levels. Such treatment falls far short of providing a reclaimed domestic wastewater that can properly be considered safe for those who golf on golf courses, play in parks or playgrounds, etc. that are irrigated with reclaimed domestic wastewaters treated to only this standard.

Further, there is concern that the residual potentially hazardous or otherwise deleterious chemicals and pathogenic organisms in secondary treated domestic wastewaters could through repeated applications to golf courses, ornamental shrubbery and other irrigation result in sufficient buildup of these chemicals and these pathogens on the vegetation and in the soils to represent a threat to water quality for the waters receiving stormwater runoff from the reclaimed domestic wastewater irrigated areas. Yates (1994) has reviewed the information available on the pathogens in domestic wastewaters that are used in golf course irrigation.

Presented below is a summary of the recommendations for the minimum monitoring program that should be conducted to significantly reduce the threat to public health and the environment due to the residual pathogenic organisms and hazardous or otherwise deleterious chemicals that are present in reclaimed domestic wastewaters.

Performance Standards for Reclaimed Domestic Wastewater Treatment

The performance standard that should be achieved in any domestic wastewater reuse project is one of treating the domestic wastewaters to a sufficient degree to control waterborne pathogens so that those who use a golf course, park, playground, softball field, botanical garden or any area irrigated with reclaimed domestic wastewaters experience no increased risk of disease compared to the situation that would exist if the area was irrigated with typically treated domestic water supplies.

Today, the sanitary quality of domestic water supplies and reclaimed domestic wastewaters are judged by the fecal coliform standard. It has been known since the 1940's that this standard will not protect public health from enteroviruses and cyst-forming protozoans (Lee and Jones-Lee 1993). While it has been known for many years that about one million people per year become ill and about 1,000 people per year die in the US due to infections caused by enteroviruses and cyst-forming protozoans in treated domestic water supplies that meet the fecal coliform standard, it was not until the Milwaukee Cryptosporidium outbreak that occurred in this city's treated domestic water supply in April 1993, that sufficient attention has been given to the inadequate treatment standards that have been used for many years in judging the safety of domestic water supply's sanitary quality. The Milwaukee epidemic, in which 400,000 people became ill and about 100 people died, took place through a water supply that met fecal coliform standards.

As a result of the Milwaukee Cryptosporidium epidemic, it has now become well known that enteroviruses and Cryptosporidium are commonly present in waters treated to meet the fecal coliform standard. Therefore, those who have contact with these waters are exposed to part of the endemic waterborne pathogen problem that exists in the US that causes large numbers of people to become ill with diarrhea, vomiting, etc. and a few people, especially the very young, the elderly and those with system immune deficiencies, to die.

In March 1995, the Executive Committee of the American Water Works Association acknowledged that treated domestic water supplies that meet current standards are not sterile. This Committee informed water utilities that they should inform their customers that those in the sensitive populations should routinely boil their water supplies that meet fecal coliform standards to protect public health (AWWA 1995).

The magnitude of public health problems associated with contact with inadequately treated reclaimed domestic wastewaters that just meet fecal coliform standards is significantly greater than for those who have the same kind of contact with treated domestic water supplies that just meet fecal coliform standards. This arises from the fact that domestic wastewaters typically contain far greater concentrations of pathogenic enteroviruses and protozoan cysts than typical domestic water supplies.

While there are some who assert that high degrees of treatment of domestic wastewaters are not needed to reclaim such wastewaters for use for irrigation of golf courses, parks, ornamental shrubbery, etc., such an approach is very short sighted and fails to recognize the significant public health threat that residual pathogens in reclaimed domestic wastewaters that just meet fecal coliform standards represent. Also, the residual chemical constituents in reclaimed domestic wastewaters can be a significant threat to stormwater runoff quality and for use for groundwater recharge as part of development of groundwater-based domestic water supplies. Lee and Jones (1995a,b,c) have reviewed these issues and provided guidance on the approach that should be taken in reuse of reclaimed domestic wastewaters as they may impact groundwater and aquifer quality and stormwater runoff.

There are a variety of approaches that are used to provide reclaimed domestic wastewater treatment before reuse for irrigation of ornamental shrubbery, parks, playgrounds, and golf courses etc. In California, these can range from minimum Department of Health Services treatment standards which include disinfection to meet fecal coliform standards of an "oxidized" secondary effluent to full treatment involving membrane filtration and/or reverse osmosis and activated carbon bed treatment of the effluent. The spraying of the reclaimed domestic wastewater irrigation water must be conducted in such a way as to avoid spraying the reclaimed domestic wastewater on golfers and others who are in the area of application. Further, there shall be no spraying of the reclaimed domestic wastewaters on drinking fountains.

It is important to not assume that even treatment of domestic wastewaters through activated sludge or trickling filters followed by secondary clarification with alum or iron/polymer addition, rapid sand filtration, chlorination and dechlorination will produce a reclaimed domestic wastewater that can be safely used for irrigation of areas that the public will use. It is important to remember that Milwaukee was practicing treatment that exceeded the standards typically associated with these treatment processes when the Cryptosporidium outbreak occurred.

While some adopt technology-based standards for developing the treatment approaches for domestic wastewater reclamation, the proper approach should be based on the performance standard for the treated domestic wastewaters. It is not the issue of just disinfection to meet fecal coliform standards. It is disinfection to control pathogenic enteroviruses and protozoan cysts to very low levels not significantly different from those associated with treated domestic water supplies today. The key to public health protection from pathogenic organisms and residual chemical constituents is the development and operation of a reliable, intensive monitoring program of the effluent and at the point of use of the reclaimed domestic wastewater.

It is important to note that in most reclaimed domestic wastewater reuse projects that receive only minimal treatment, the public typically does not come into direct contact with the domestic wastewater; however, they can and frequently do come into contact with the residual pathogenic organisms and hazardous or otherwise deleterious chemicals that were present in the wastewater applied to the area. The reuse area monitoring is designed to determine whether there are any significant problems associated with such contact.

A suggested monitoring program is presented below.

Monitoring of Reclaimed Domestic Wastewater Reuse

The monitoring program designed to protect public health and the environment from the residual constituents in domestic reclaimed wastewaters should include intensive effluent monitoring as well as monitoring of the areas where the reclaimed domestic wastewaters are used as well as any runoff waters from these areas.

Effluent Monitoring

The reclaimed domestic wastewater effluent should be monitored using state-of-the-science techniques for fecal coliforms, enteroviruses and protozoan cysts on a weekly basis. This monitoring should be done so that sampling of the effluent is variable during the seven-day week to be representative of the range of conditions that occur in effluent quality over the 24-hour day and seven-day week. Also, particular attention should be given to monitoring during unusual situations such as stormwater runoff events which lead to increased hydraulic loading on the treatment plant.

It may be possible to reduce the frequency of monitoring of the effluent for enteroviruses and protozoan cysts to every two weeks except during unusual flow situations or plant upset once a sufficient monitoring experience has been developed where it is possible to reliably predict the results of the monitoring for the next monitoring period based on the past monitoring experience. When such experience is gained, it then would be appropriate to reduce the frequency of monitoring so long as the past monitoring results provide a reliable indication of what the next monitoring event finds on the characteristics of the effluent.

Reuse Area Monitoring

For areas such as golf courses, parks, playgrounds, softball field, botanical gardens and other areas where the public will have contact with the residual constituents in the reclaimed domestic wastewaters that are applied to the area, it is important to sample the turf, grass and other vegetation and soil for an accumulation of pathogenic organisms, such as protozoan cysts and enteroviruses. This monitoring is essential to evaluate the reliability of the effluent monitoring and to determine what the public is actually exposed to through the use of the areas that receive reclaimed domestic wastewaters. It should not be assumed that just because the effluent monitoring does not detect any problems, that there is not sufficient buildup of potentially hazardous situations that could be a threat to public health and the environment.

Stormwater Runoff Monitoring

Specific sampling of the stormwater runoff from representative storms from the reuse irrigation areas should be conducted to determine whether the residual pathogenic organisms and hazardous or otherwise deleterious chemicals in the reclaimed domestic wastewaters are detrimental to the designated beneficial uses of the receiving waters for the stormwater runoff. Lee and Jones-Lee (1995d) have recently described a stormwater runoff evaluation monitoring approach that can be used to assess whether chemical constituents and pathogenic organisms in stormwater runoff from an area is significantly adversely impacting the designated beneficial uses of the receiving waters for the stormwater runoff. Rather than mechanical end-of-the-pipe or receiving water monitoring, they advocate highly directed, site-specific studies that address whether constituents in the stormwater runoff are adverse to the receiving water water quality.

If runoff occurs from the reclaimed domestic wastewater irrigated areas at times other than during storms, then monitoring of this runoff should be practiced on a routine basis, such as every two weeks to one month, when it occurs.

Groundwater Monitoring

If there is significant potential for groundwater recharge associated with the reclaimed domestic wastewater reuse areas, then monitoring of the unsaturated and saturated parts of the aquifer should be conducted to detect incipient pollution by reclaimed domestic wastewater derived constituents. The groundwater monitoring should be conducted on a quarterly basis in order to detect seasonal impacts on groundwater recharge of constituents in the reclaimed domestic wastewater. Lee and Jones-Lee (1995a,b) provide additional information on groundwater monitoring associated with reclaimed domestic wastewater recharge.

Use of the Monitoring Data in Public Health and Environmental Protection

The monitoring program should be supervised by individual(s) who are highly knowledgeable in sanitary quality and water quality issues. The data should be critically examined as it is collected. If unexpected results occur, then additional sampling should be undertaken to confirm that the unexpected results are representative, and if representative, explain why they are occurring. Lee and Jones-Lee (1992) have provided guidance on conducting water quality monitoring programs.

Informing the Public of the Hazards of Using Reclaimed Domestic Wastewater Irrigated Areas

For those areas that either do not conduct a monitoring program of this type or where such a monitoring program shows that the irrigated area contains potentially pathogenic enteroviruses and/or cyst-forming protozoans, the least that should be done is to post large signs in the area that is irrigated with domestic reclaimed wastewaters stating that, "The area has been irrigated with reclaimed domestic wastewaters that have not necessarily been adequately treated to protect public health and the environment. Persons using this area could experience illness, and possibly death due to the residual pathogenic organisms and hazardous chemicals in the reclaimed domestic wastewaters used to irrigate the area."

Additional Information

Additional information on many of the areas summarized in this review is provided in the references. Copies of the authors' references are available from the authors upon request.

References

AWWA, "What Water Utilities Can Do to Minimize Public Exposure to Cryptosporidium in Drinking Water," American Water Works Association Executive Committee White Paper, Executive Committee of American Water Works Association, Mainstream 39:6 (1995).

Lee, G. F. and Jones-Lee, A., "Guidance for Conducting Water Quality Studies for Developing Control Programs for Toxic Contaminants in Wastewaters and Stormwater Runoff," Report of G. Fred Lee & Associates, El Macero, CA, 30pp, July (1992).

Lee, G. F. and Jones-Lee, A., "Public Health Significance of Waterborne Pathogens in Domestic Water Supplies and Reclaimed Water and Supplemental Information on Public Health Significance of Waterborne Pathogens in Domestic Water Supplies and Reclaimed Water," Report to Cal Environmental Protection Agency Comparative Risk Project, Sacramento, CA (1993).

Lee, G. F., and Jones-Lee, A., "Public Health and Environmental Safety of Reclaimed Wastewater Reuse," Published in Proc. Seventh Biennial Symposium on Artificial Recharge of Groundwater, The Role of Recharge in Integrated Water Management, Water Resources Research Center, University of Arizona, Tucson, AZ, May (1995a).

Lee, G. F., and Jones-Lee, A., ""Water Quality Aspects of Groundwater Recharge: Chemical Characteristics of Recharge Waters and Long-Term Liabilities of Recharge Projects," Artificial Recharge of Ground Water, II, Proceedings Second International Symposium on Artificial Recharge of Ground Water, American Society of Civil Engineers, NY, pp. 502-511 (1995b).

Lee, G. F., and Jones-Lee, A., "Total Dissolved Solids and Groundwater Quality Protection," Artificial Recharge of Ground Water, II, Proceedings Second International Symposium on Artificial Recharge of Ground Water, American Society of Civil Engineers, NY, pp. 612-618 (1995c).

Lee, G. F., and Jones-Lee, A., "Evaluation Monitoring of Stormwater Runoff Water Quality Impacts: Initial Screening of Receiving Waters," to be presented at the EPRI Conference on Water Quality, November (1995d).

Yates, M. V., Monitoring Concerns and Procedures for Human Health Effects, In: Wastewater Reuse for Golf Course Irrigation, US Golf Association, Lewis Publishers, Boca Raton, FL, pp 143-171 (1994).

Reference as:"Lee, G. F. and Jones-Lee, A., 'Monitoring Reclaimed Domestic Wastewater Usage on Public Parkland Vegetation to Reduce Risks,' Water Engineering & Management, 142:28-29,37 (1995)."

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