Comparisons of particle counts made by counters and counts made by microscopic processes suggest counters accurately indicate removal efficiency. Particle counting methods for use in a water treatment facility were analyzed to compare counts made by a particle counter with a forward‐angle light scatter (FALS) sensor with counts made with a scanning electron microscope and by microscopic particulate analysis. A separate study compared an FALS sensor with a light obscuration sensor when challenged with latex spheres and cultured microorganisms and when performing continuous in‐line counts of the facility's filter effluent. Log removal values were comparable among the particle counting methods and did not vary significantly across various size ranges of an FALS sensor. Microorganisms were undersized by both sensor types compared with sizes determined with an optical microscope. These results suggest counters accurately indicate facility particle removal efficiency. However, counts made by a particle counter within a specific size range should be interpreted after characterizing the nature of the particles in the source

The Champlain Water District's Peter L. Jacob Filtration Facility in Northwestern Vermont treats low‐turbidity raw water from Lake Champlain's Shelburne Bay with the goal of producing consistent high‐quality finished water. From 1980 to 1989, the facility consisted of two deep‐bed, dual‐media filters and one converted deep‐bed, multimedia filter, preceded by flocculation basins operated in the direct filtration mode. In 1991, a phased three‐year facility upgrade was completed, that made modifications to the flocculation basins and additions to the filtration and disinfection barriers. This article discusses the means by which the facility was evaluated. The district invited an independent third‐party assessor to review the treatment facility in 1994. This paper discusses in detail the self‐assessment process, the recommendations that were issued, and the actions which resulted from the assessment.

Treating livestock manure with drinking water treatment residuals (WTRs) can reduce soluble phosphorus (P) and decrease the risk of P losses from land‐applied manure. At the same time, such beneficial use could provide the water treatment industry with an economical alternative for management of its by‐products. A 10‐day experiment was conducted to assess the effect of addition of 1‐50% w/w alum‐based WTRs on the P content of liquid dairy manure. Reductions in manure‐soluble P concentrations of 6‐79% were achieved at doses ranging from 1 to 50%. Total P levels in manure were reduced by 9‐25% at WTR doses of 10‐50%. Most P reduction appeared to be achieved after 72 h following WTR addition. A WTR dose of 5‐10% could potentially achieve a 20‐30% reduction in soluble P content of liquid dairy manure; greater reductions in soluble P appear to be achievable with higher WTR doses.

Drought, wildfires, storms, and other potentially serious events can significantly impact source water quality. Water treatment plant staff must be especially vigilant and prepared to maintain effective water treatment and treated water quality during such occurrences.