Developing a Culture of Elite SVI Management

I can remember hearing the unwelcome advice ‘You need to develop an operational culture of low sludge volume indexes (SVI’s)’. My first reaction was to think ‘mind your own business’. With time, I realized the wisdom of the counsel. When the advice was given, our SVI’s ranged from 120-500 and we didn’t really know why. We relied on large clarifiers and shock doses of hypochlorite to manage when settling was bad.

Managing your SVI’s (Sludge Volume Indexes)

Managing SVI’s is important because the original clarifier design likely assumed average SVI’s and clarifier effluent is sensitive to the measurement. It is also one of the few variables that can be controlled by operators once a system is placed into service.

Developing a culture of elite SVI management starts with communicating the goal and getting operations, lab and engineering support personnel to collaborate. Managing SVI’s well also requires an understanding of relationships between SVI’s and temperature, weekly changes in loading, sludge retention time, microscopic examinations, RAS chlorination strategies, aeration performance, and primary effluent biological oxygen demand. Understanding these relationships comes from historical data analysis and targeted inquiry and sampling by the group.

Accepting advice requires humility, self-reflection, and a growth mindset. The challenge to create a ‘culture of low SVI’s’ ultimately caused our organization to take responsibility for its high SVI’s and ultimately - manage them well.

Do you accept the challenge to develop a culture of low SVI’s?