The line “To the sea, to the sea! The white gulls are crying, The wind is blowing, and the white foam is flying” was written by J. R. R. Tolkien and is often associated with themes of longing, farewell, and the call of the ocean. In this verse, the sea is portrayed as a symbol of freedom and destiny, while the crying gulls and flying foam are depicted as voices of nature calling the traveler home. Through vivid imagery and rhythmic flow, a deep emotional connection to the natural world is expressed, and Tolkien’s love of mythic journeys is beautifully reflected.
Foaming in winery wastewater treatment systems is a frequent and frustrating issue. In activated sludge plants, foam appears when air bubbles form and are stabilized by organic compounds and microbial activity, preventing them from collapsing. The result is a thick, persistent foam layer that can overflow tanks and disrupt biological processes.
The main causes of winery effluent foaming include high concentrations of organic matter, such as ethanol, sugars, and surfactants from cleaning operations. These compounds reduce surface tension and promote bubble stability. In addition, filamentous bacteria such as Nocardia and Microthrix parvicella often proliferate under high organic loads or nutrient imbalance. Their hydrophobic surfaces trap air, anchoring foam to the sludge. Seasonal fluctuations in flow and loading, common in wineries, further aggravate the problem.
Effective foam control begins with optimizing plant operation. Maintaining the correct food-to-microorganism (F/M) ratio, sludge age, and nutrient balance (particularly nitrogen and phosphorus) helps sustain healthy biomass. Aeration levels should be adjusted to prevent low-oxygen zones where filamentous organisms thrive.
If foaming persists, surface chlorination, hydrogen peroxide dosing, or mechanical foam breakers can be applied. Silicone-based antifoam agents may also be used sparingly. Upstream management is equally important — segregating cleaning chemicals and stabilizing inflows can greatly reduce foam formation.
In summary, foaming in winery activated sludge systems results from a mix of organic surfactants, microbial imbalance, and variable operating conditions. By combining biological insight with operational discipline, treatment plants can maintain clear surfaces and efficient winery wastewater performance year-round.