Conn Creek was using two 7.5 HP aerators and one 5 HP to treat a 500,000-gallon process wastewater pond. The winey was unable to meet Napa County Health Department standards for land applying their wastewater, i.e., to use it as irrigation water, due to high TSS levels. As a result, they had to discharge the wastewater to an underground infiltrator leach field. The winery had dredged their pond several years prior at a cost of $75,000 and yet had built up 18″ of sludge in the pond. In addition, they had an odor issue which was problematic due to the pond’s proximity to the tasting room.
ClearBlu replaced the existing aerators with new low energy ultra-fine bubble surface aerators, reducing the horsepower in the pond from 20 to 9. When we started treatment in March of 2009, the effluent TSS was 146 mg/l. By late April it was 28 and by June it was down to 20 mg/l. The most recent test result from February 2010 showed a TSS level of 35, BOD level of 19, and an LDO of 9 mg/l. We reduced the sludge level in the pond by 6″ in 4 months and by November of 2009 the sludge depth was down to 4″. The pond now has very soft dark liquid on the bottom of the pond with no sludge. To keep initial cost considerations in mind, this particular system was sized for slightly less than harvest loading and thus the harvest season brings light sludge accumulation reaching approximately 12″. Once harvest has ended the pond has time to play a little catch-up and the sludge is digested over a few months.
ClearBlu is happy to report that for the first time in a long time Conn Creek is finally meeting all necessary requirements for land application and have begun irrigating their vineyard using treated wastewater.