PROBLEM
Tom’s River, NJ, operates an iron-removal facility to treat part of its well water supply. The treatment involves aeration, alum coagulation, settling and filtration. Lime and sodium hypochlorite are fed post-filtration. The water is filtered through an Inflico Automatic Backwash (ABW) Filter that allows for continuous operation. The filter media was replaced in the spring of 2006, but during the summer, heavy fouling of the media significantly reduced the performance. CH2M Hill recommended using Media Master chemical cleaning by Blue Earth Labs to restore filter flow and performance.
SOLUTION
In March of 2007 Blue Earth Labs conducted extensive laboratory analysis on the filter media sample. Microscopic analysis showed that the anthracite and sand had mostly aggregated to mudballs. Individual filter media particles were not visible and washing could not effectively break up the media aggregates.
Numerous chemical combinations of various Blue Earth Labs cleaning chemicals were explored. This particular media fouling proved to be especially resilient and required a two-step process. The most effective treatment consisted of first applying 0.2 gallons of Biogrowth Remover™ and 0.2 gallons of Floran Cataylyst® per square foot of filter media and allowing the reaction to go to completion. After backwashing, eight pounds of Media Master was applied in granular form along with 0.2 gallons of Floran Cataylst, per square feet of filter media. This treatment protocol resulted in a dry weight loss of ~20%.
The media treatment generated a large amount of foam and the runoff contained a large amount of suspended solids which were pumped into the backwash holding facility, neutralized, and discharged to the sanitary sewer. After treatment the original particle size, shape and density of the media components were restored. Based on laboratory calculations 8-10,000 pounds of buildup had been removed from the filter.
RESULTS
Blue Earth Labs’ two-step filter media cleaning treatment restored the fouled filter bed to near new operating conditions. The treatment restored the filtration capacity and effluent water quality once completed at a substantial savings, in both time and money, compared to filter media replacement.