TMDLs and Chesapeake Bay Protection

How Recent Changes in the Clean Water Act Favor Spray Irrigation

To achieve programmatic levels of economic development, many jurisdictions with existing wastewater treatment facilities have implemented Enhanced Nutrient Reduction (ENR) technologies and related wastewater treatment upgrades to accommodate requirements set forth within the federal Clean Water Act (CWA) vis-à-vis Total Maximum Daily Loads (TMDLs). If these same wastewater plants are at or approaching full capacity, an altogether new disposal option is required to accommodate future flow expansion.

One such option is to implement spray irrigation. This wastewater discharge method is popular amongst municipalities/communities and land owners (e.g., farmers, golf courses, etc.) as a mutually beneficial means of disposing wastewater, offsetting nutrient loads, and providing a source of irrigation for surrounding agricultural and/or aesthetic uses. Spray irrigation may be implemented in proportion to plant uptake needs, or in excess of their needs if soil and groundwater conditions prove sufficiently accommodating.

In the Chesapeake Bay watershed, many industrial and municipal point-source discharges already are highly treated because of longstanding Bay protection policies. The multi-stage Chesapeake Bay protection agreements of 1983, 1987 and 1990 considered TMDL-based pollutant loads through apportionment formulae which collectively constitute a nutrient loading strategy.

The adopted procedures make little allowance for new point-source discharges and generally mandate degree-of-treatment improvements commensurate with increases in discharge volumes. For some growing systems already implementing Enhanced Nutrient Removal (ENR) technology (or seeking to avoid the cost of an ENR upgrade), spray irrigation constitutes a viable option provided that sufficient acreage of suitable land is available.

Under most present TMDL implementation programs, nutrient loads “go away” when treated wastewater is discharged via a land treatment method such spray irrigation. As municipalities and other wastewater utilities implement recommendations set forth in recently completed Water Resources Elements and Comprehensive Plans, groundwater discharges such as spray irrigation will be increasingly popular as a means to support continued economic growth in a manner protective of natural resources such as the Chesapeake Bay.

Representative professional services performed by ALWI’s wastewater division include the following:

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