Crown Point selected In-Pipe Technology Company®, LLC with goals to reduce the quantity of waste sludge for disposal, increase organic capacity, and control odors at the plant. Crown Point, located in northwest Indiana approximately 45 miles from Chicago, spent nearly $200,000 on sludge expenses from polymer to hauling and disposal fees. Population growth in Crown Point increased sludge production that required expansion of the existing sludge storage building. In addition, they hoped increasing the organic capacity would increase the MCRT (Mean Cell Residence Time) to push back their need for a new anaerobic digester expected to cost $1 million.

Performance History and Discussion 

Crown Point selected In-Pipe Technology Company®, LLC with goals to reduce the quantity of waste sludge for disposal, increase organic capacity, and control odors at the plant. Crown Point, located in northwest Indiana approximately 45 miles from Chicago, spent nearly $200,000 on sludge expenses from polymer to hauling and disposal fees. Population growth in Crown Point increased sludge production that required expansion of the existing sludge storage building. In addition, they hoped increasing the organic capacity would increase the MCRT (Mean Cell Residence Time) to push back their need for a new anaerobic digester expected to cost $1 million.

 After five months of the technology in place, Crown Point decreased the WAS (Waste Activated Sludge) production by 35%, improved the sludge volume index by greater than 35%, and increased volatile solids reductions. After nine months, the plant reported decreased influent TSS load by 25% from 4,773 lbs/ day to 3,565 lbs/day, and decreased ammonia load by 45% from 1,387 lbs/day to 755 lbs/day. One note worthy improvement was reduced filtrate ammonia concentration for stored sludge. This load ultimately increases the loading on the plant as the side-stream filtrate of ammonia is returned. Reducing this filtrate load was an unexpected benefit of the technology. 

During the winter of 2008, the plant experienced mechanical failure of two of three final clarifiers due to complications with the weather. As a result, nearly all of the biomass in the actived sludge system was eliminated through a washout of the remaining portion of MLSS. In-Pipe supplied additional microbes to select locations in the collection system and at the plant. Within two weeks, the grey, septic biomass was returned to a healthy brown color and the MLSS was rapidly rising. In a letter thanking In-Pipe, Chris Previs said “We feel we would have been in serious jeopardy of violating our permit if it was not for your quick response to our dilemma.” 

Present Conditions

In-Pipe has serviced Crown Point for more than 16 months. In a recent report to the city council, Chris cited almost 85% of In-Pipe expense was covered in savings from reductions in sludge and polymer usage, electrical consumption, and FOG control chemicals. In addition, reduced odors at the plant, an increased MCRT, and reduced O&M for sewer maintenance and cleaning were all benefits to Crown Point with In-Pipe treatment and service. The new digester and expansion of the sludge storage building are postponed without schedule and Crown Point saved approximately $170,000 on sludge, electricity, and chemical expenses.