330 likes | 474 Views
"Metal Hits at WWTP’s. Class ”A” EQ Biosolids To Class “F” And Back Again. Class “B” tertiary treatment plant Grit removal Primaries Aeration tanks Secondary's RBC Sand filters Anaerobic digesters Discharge into trout stream. Cadillac WWTP. Microscopic Evaluation Hauling Biosolids
E N D
"Metal Hits at WWTP’s Class ”A” EQ Biosolids To Class “F” And Back Again
Class “B” tertiary treatment plant Grit removal Primaries Aeration tanks Secondary's RBC Sand filters Anaerobic digesters Discharge into trout stream Cadillac WWTP
Microscopic Evaluation Hauling Biosolids Point Source Study Wet Test We Have a problem Confirm Tests Investigation Incoming Trunk lines Factories On the trail of the Guilty Sampling Trailer The Story
Guilty Party The Meeting Results Toxic Sludge Bidding Geotubes Geotubes II Disposal Outcome Story (continued)
Microscopic Evaluation • Evaluate three Activated sludge slides a day • Noticed decrease in life on Mondays • Increased life all week • Decreased life next Monday • Life in tanks are not stable • Begin trying changing operations.
Biosolids • Five years of study for class “A” EQ status • Sent in application for certification • Received certification • Applied 1st time as Certified Class ”A” EQ • Emptied both biosolids tanks(800K &700K)
Point Source Study • DEQ show up to do Point Source Study • Everything appears to be normal • Received a phone call on biosolids • Sample of digester #1 to #2 transfer is Hot! • Zinc Level shows 6010mg/L • Are our numbers right?
Wet Test • Sent in WET test sample to ASCI Lab. • Before second sample get call • Everything is dead in 100%/66% samples • What is happening • Sodium thiosulfate remaining sample • No die off. • Heavy metal present.
We have a problem • Low bug populations • High zinc level in Point Source biosolids • Toxicity caused by heavy metal • Better find out what’s wrong
Confirm tests • Do we have or had a problem? • Start testing influent & effluent daily • Internal Testing lab. • Test seven days a week • Start testing Digester solids • What for results to see what we will do.
Investigation • We have a problem • Start testing trunk lines & plant • Start testing industries on a more frequent basis. • Two Isco Samplers plus Plant Sampler • Hard to test and keep IPP program to date
Incoming Trunk Lines • Four Trunk lines Converge at WWTP • Able to test each line on plant ground • Narrowed down to two trunk lines • Investigated further- One trunk line now • Our most Industrial trunk line. • Also had Major county flow in it
Factories • Many Industries on line plus county. • Must eliminate one at a time. County first • Military Pallets • Rubber Factories • Boat manufacture • Power plant • Foundry
On the Trail of the Guilty • Always Chasing tail • Couldn’t find guilty party • Had Industry that was retrofitting Cooling tower at the correct time. Not guilty • Only one industry never had a hit at plant while we were sampling it. • Couldn’t catch.
Sampling Trailer • Sampling trailer Problem? • Great deterrent • Community Awareness • Industry Tip Off ??
Guilty Party • Have idea who is guilty party can’t prove • Sampled 1 1/2 weeks straight no upsets • Moved over weekend/Had upset • Tested a week longer. No upsets • Moved and then hid the sampler • Had “hot” sample from industry • Should have known it was the Foundry
The Meeting • Called Industry about problem • Set meeting date • Found out they had been experimenting • Oil cans and Soup cans • pH in treatment system very low • Kept zinc soluble • Very hard on equipment
Results • Never said the word Zinc • Never admitted to wrong doing • Offer to help pay for cleanup • Doing this out of sense of community • They would help us • They were hoping we would help them • Set up extra monitoring and limits
Toxic Sludge • Now that problem taken care of what do we do with sludge. • Store all in one tank • Keep adding until level falls below ceiling • Start filling second tank with Class “B”
Bidding • Decided to put out to bid • Six bidders • Three within 8/10 of a cent • One of low bidder was our own hauler • Council went with Low bid • Was an application not familiar with
Geotubes • Fill tubes with sludge • Add polymers • Sludge will dewater • Tubes will weep • Add more sludge • Repeat until tubes are filled • Wait until dry
Geotubes II • Filled tubes • Suppose to be 2 tubes • Became 5 tubes • Needed more polymer • More space • Time,time,time
Disposal • Never dried fully • Add sawdust • Take to landfill • Increased landfill rates • More cost and time • Pleasantly surprised contractor stayed .
Outcome • Be vigilant • Test often • Test on weekends • Be prepared • Work with industry • Want to keep industry not drive away