Foams or emulsions (hereinafter collectively referred to as “foams”) are ubiquitous in various processing operations. Foam sometimes creates or provides certain desirable product characteristics, such as a specific consistency of food or taste in a beverage (e.g., beer), and is thus considered advantageous. Other times, foam is an undesired byproduct, such as during wastewater treatment. In such cases, the foam must be eliminated, or at least monitored and kept in check.
Many systems and processes rely on human intervention for monitoring and controlling foaming. For instance, the concrete industry and associated cement, mineral admixture and chemical admixture supplier industries, use visual, subjective measurements or ASTM methods to determine both the level to which air entraining agents, or “AEA's,” are to be dosed into concrete mix to meet construction specifications and to gauge stability and the foaming characteristics of AEA's. AEA use is mandated by state and U.S. federal transportation agencies in concrete highway and bridge construction and in building construction standards (e.g., ACI 318 Building Code) whenever temperatures below 32° F. are experienced.
To gauge the proper amount of AEA to be added to concrete mix, tests are manually performed beforehand on a sample to assess the foam stability. This testing involves a visual inspection of the sample to monitor the behavior of the foam, such as the amount of bubbles breaking in the foam over a given time period, to assess whether more AEA must be added (in which case the test is repeated until the appropriate amount is determined). Obviously, this is not only a time consuming, laborious process that can lead to frustration, but also a highly subjective one that often leads to an inconsistent end product.
Similarly, under current industry-wide practices, wastewater plants manually measure and monitor the level of foam created during the aeration portion of the treatment process. This requires workers to visually inspect, manually extract, and perform optical measurements on water samples to quantify the cause of the excessive foaming (which is typically microbial in nature) and take appropriate corrective measures. This is a laborious undertaking involving careful sampling and analysis of the resulting data. Moreover, reestablishing a proper balance of microbes or other operational parameters of the system can take up to one week. This time delay increases the probability of excessive foaming in the interim, which can ultimately lead to a deleterious and hazardous overflow requiring emergency measures to control or contain.
Accordingly, the need exists for an automated manner for monitoring or controlling foaming, whether created for beneficial purposes or otherwise. The approach taken should be capable of monitoring the foam with the ability to make an objective characterization. Appropriate control measures could then be taken based on this characterization, such as to increase, decrease, or stabilize the foaming. Together, this monitoring and control would decrease the amount of manual labor and subjectivity in characterizing the foam, thus providing a significant savings in terms of time and money in a myriad of commercial and industrial processes.