The sludge in West Longview’s old sewage treatment ponds appears to meet state and federal standards for removal and use elsewhere as a soil amendment, which would allow the city to reclaim the 46-acre property.
With the sludge gone, the West Longview lagoon site could be turned into a recreation area or wetlands or sold for residential or commercial development, city officials say.
Thursday, the City Council approved a $108,000 contract with the Longview engineering firm Gibbs & Olson to conduct a second round of sampling and testing of the sludge. Tests will further determine the concentrations of certain pollutants, all of which met safety standards in previous tests.
The firm recommends removing the sludge by dredging, drying it onsite and the trucking it away. Gibbs & Olson also will prepare contracts to scoop out the biosolids and apply them as a soil amendment — fertilizer, essentially — at an approved site.
The sludge is 2.5 feet deep in one sewage lagoon and about a foot deep in the other three lagoons. The water covering the sludge is about 6 feet deep.
The city has used the lagoons 43 years to treat household wastewater from the city’s west end. Bacteria and sunlight break down the sewage, and the remaining organic “biosolids” settle to the bottom. The city can’t use the ponds anymore because they’re at capacity and don’t treat the water adequately to meet stricter clean water standards.
In March, the city finished a $25 million project to divert the sewage to the Three Rivers Regional Wastewater Treatment Plant on Fibre Way. The city now has about 18 months to obtain state approval of a biosolids disposal plan and begin removing the sludge from the ponds.
Engineers expect the sludge removal will begin in May or June and may take up to three years to finish.