This is an attempt to correct a number of inaccuracies in a recent letter to the editor by Steve Nisky concerning the question of whether or not a wetland treatment system is the best solution for St. Croix sewage problems.
First, for those readers who may not know the vocabulary of wastewater treatment let me define a few basic terms I'll be using. Primary treatment is defined as the removal of about 30 percent of the TSS (total suspended solids, the particles floating in the water) and 50 percent of the BOD (biochemical oxygen demand) in the water (accomplished by settling). BOD is a measure of the bacterial demand for oxygen in a sample of water. If BOD is too high, bacteria will strip the water of its oxygen and suffocate fish. Secondary treatment is defined as treating wastewater to a point where it contains no more than 30 m/l (milligrams per liter) of TSS and BOD. This is the level of treatment that EPA is mandating for St. Croix. Tertiary treatment is defined as treating wastewater to a point where is to contain no more than 10 mg/l of TSS and BOD and has much of the nitrogen and phosphorous removed as well. Tertiary treatment gets wastewater close to drinking water standards and makes it reusable for the irrigation of parks and farm land.
Wastewater arriving to the existing treatment plant at Anguilla undergoes primary treatment (settling). Wastewater enters two large deep tanks where it is retained for about two hours, long enough for solids to settle to the bottom of these tanks, before being discharged to sea. In his letter Mr. Nisky asserted that the existing primary treatment plant at Anguilla has never met the US Environmental Protection Agency's (EPA) treatment standards and must be replaced in order for secondary treatment to be effective. It appears he is unaware that for the last three years, under a private company's operation, the Anguilla primary plant has met all of EPA's discharge standards for primary treatment. The plant's less than admirable operation and maintenance history under the V.I. Public Works Department was responsible for its previous failure to meet EPA's permit limits not the plant's design. There is no need to "replace" the plant with a new one as Mr. Nisky suggests this would be like throwing the baby out with the bathwater and would be unnecessarily expensive.
Mr. Nisky also states that the proposed wetland treatment system would "consume large amounts of land" and that there would be the "smell of naturally decaying waste in the great outdoors". Mr. Nisky again misses the mark here as the system being proposed will only require 26-acres of land to treat all of St. Croix's wastewater. The system is completely dry on its surface and would appear, to someone standing on top, to be a dry grassy field . The surface of the proposed system, in fact, will be utilized for the year-round grazing of goats. Because the wet area of this "wetland" is actually six inches below the ground's surface, there are no odors, no "decaying waste", and no place for mosquitoes to breed. Anyone who has visited a neighbor's house with a properly designed leach field for their septic tank (a very close cousin of the proposed wetland treatment system) knows that it's dry on the surface, odor free, and grows grass very well.
Mr. Nisky's assertion that subsurface wetland treatment systems are "located in remote areas, away from the general population" again points out his lack of knowledge about the technology. Because these systems are below ground, they can be located immediately adjacent to homes, businesses, schools, or hospitals without concern for odors, mosquitoes, or public heath issues. At the April 14 Legislature hearing on the technology, Senators visited by phone with John Jankiewicz, Public Works director for the town of Highland, N.Y. that operates a subsurface wetland ((845) 691-2400). The Highland system sits adjacent to a 500-employee lighting manufacturer whose employees use the top of the system as a park during their lunch breaks. Mr. Nisky might also want to visit the Antigua Airport where a wetland treatment system, servicing a 60-acre commercial park, is used as a park and landscaping feature in the development and sits immediately adjacent to the offices of major banks and internet marketing firms. Because the system is so attractive, it is featured prominently in promotional literature used to attract businesses to the commercial park.
Mr. Nisky's claim that the wetland system proposed for St. Croix could not be located near the airport because it would "would attract more birds, which are a major concern of aviation" is also incorrect. His claim would only be valid if a "surface flow" wetland were being proposed, which it is not. What is being proposed is a "sub-surface" wetland treatment system whose surface is dry and managed as grazing lands for goats If Mr. Nisky had checked with the Federal Aviation Administration, as we did over two years ago, he would have found that the agency has no concerns with a subsurface system's proximity to the airport as long as it has no open water (this is what attracts birds) and is managed as grass land.
Mr. Nisky's statement that "organizations such as SEA can better serve the population by allowing improvements to move forward, and not impeding progress" shows that he is apparently out of touch with the St. Croix community's broad support for the wetland treatment system. Team St. Croix, a coalition of 16 community organizations (SEA is a member organization), is the organization championing the wetland treatment system for St. Croix. Team St. Croix includes organizations like the STX Chamber of Commerce, the STX Board of Realtors, STX Hotel and Tourism Association, Frederiksted Economic Development Association, St. Croix Taxi Federation to name a few. I would suggest that these organizations and the residents of St. Croix, who have researched wetland technology and its science for almost five years, have a better handle on what is the right solution for St. Croix than Mr. Nisky.
There are several reasons why the wetland treatment system that has been proposed for St. Croix enjoys wide community support. First, it is far less expensive to operate because it uses little to no electricity to treat wastewater (wastewater moves through the system by gravity). By comparison the proposed mechanical plant will consume over $70,000/month of electricity (at last year's energy prices) when operating at full capacity. As oil prices climb, so will our monthly bill to operate the mechanical system, translating into considerably higher utility costs for residents and businesses.
Second, the wetland system is about $11 million less expensive to build. The combined construction and annual operations and maintenance savings means we will spend $31 million less to clean our wastewater. These savings can be better used to repair the pipes, manholes, and pump stations that are responsible for the frequent sewage spills on St. Croix. Those savings could also be used to underwrite the cost of installing the pipeline and irrigation infrastructure needed to deliver the one million gallons/day of reclaimed water that would be available to farms and golf courses on St. Croix utilizing a valuable resource we are now throwing away.
Third, the proposed wetland system provides a dual use for the land where it is located high-quality and high-yielding forage land for goats on it surface and the purification of wastewater below the surface. And fourth, the wetland can produce tertiary quality water that is suitable for tourism and farm use. The availability of 1 million/gallons/day of irrigation water will stimulate St. Croix's farm and tourism economies by increasing local food production and tourism visits to the island.
The US Environmental Protection Agency fully supports and approves of wetland treatment technology. It published a
design manual for the technology in 2000 and encourages communities to utilize this cost saving and sustainable technology where appropriate. St. Croix has all the conditions needed to successfully utilize this technology and become a leader in Caribbean. I would encourage Mr. Nisky to call EPA's senior scientist Robert Bastion in Washington, DC ((202) 564-0653) to learn more about the proven efficacy of wetland treatment technology before continuing to make unsupported claims.
Editor's note: Kelly Gloger is a wastewater specialist with Sustainable Systems & Design International, one of the two local companies that has proposed the wetland treatment system for St. Croix and would be involved in its development if selected.