MODIFIED AERATED LAGOON WITH TERTIARY WETLAND TREATMENT

摘要

In 1990, Tangipahoa Parish Sewerage District No. 1 was required to provide sewer service to an area Southeast of the City of Hammond, but lying out of the city limits, which consisted of a densely populated area of subdivisions and apartment complexes with individual or no waste treatment. None of the existing subdivision treatment plants could be expanded to service the entire eighteen (18) square mile area nor would the City of Hammond provide sewer service to the area. Several older developments had collection lines but no treatment, resulting in the discharge of large quantities of untreated waste. Further, the area was too affluent to qualify for a grant for the entire area. In addition to a sewer collection system, the area would require a sewerage treatment facility capable of treating a minimum of 200,000 gpd and a maximum of 500,000 gpd. No existing treatment process would provide the level of treatment required for the funds that were available for the project. Because of the fixed cost of the collection system only two hundred fifty thousand dollars ($250,000.00) was available to acquire the site and build the waste treatment facility. Further, the facility had to have low operating cost due to the fact that the District did not have a tax base and had to operate solely on sewer service charges. Tangipahoa Parish Sewer District No. 1, whose jurisdiction the area fell under, sought and received a low interest loan from FmHA. However, the maximum amount that could be borrowed was eight hundred thousand dollars ($800,000.00). Because of the fixed cost of the collection system, only two hundred fifty thousand dollars ($250,000.00) was available to acquire the site and build the waste treatment facility. Therefore, in 1991, a new type of facility was designed and constructed specifically for this application in order to reduce construction and operation cost and improve reliability. The facility was based on empirical design parameters amassed by the District since its inception. This facility was so successful that a second facility was constructed in the Velma Community in 1995 using LCDBG funds. Both facilities have been extensively tested to empirically determine their operating parameters and to verify the design used.