Friday, October 23, 2009

Sewedge Sludge Opportunity

The town of Canmore is currently seeking a new home for it's yearly 3,000 tonnes of sewage sludge. Until recently, it was shipped to Bowden correctional facility where it was converted to compost at a cost to the municipality of $420,000.
One project on the table is a possible deal to mix it with lime dust at Exshaw and use it for mine reclamation, the lime neutralizing any bio-hazard.

3,000 tonnes of sewage sludge seems too precious for land reclamation.

Ideas anyone?


CaptainOrange said...

That's about $0.10/day for each permanent resident to transform their shit into shinola. Too bad the facility is closing, or I'd say sign me up.

rainswept said...

I wonder if raising awareness of the role federal prisons play in subsidizing their lifestyles isn't good for people. Not only are the programs run at a deficit - of course - but the outputs flow for almost no cost into the local economy.

"The mayor of Dorchester said Thursday that... the farm is also the source of free, fresh produce for several food banks, non-profit fundraisers and charities in the area."

Prison populations working for a pittance* depress the value of honest labour, and are a little acknowledged subsidy to the local economy that breeds dependence on prison labour (as Canmore illustrates) and generates a societal mandate for the prison system.

One might say that towns proximate to these institutions suffer from "prison addiction".

* In 2007 the daily wage for a federal prisoner was $6.90!

Kevin Aschim said...

The 2 most valuable components of the sludge are reactive Nitrogen as ammonia and phosphate. Adding lime raises the pH of the sludge and causes entrained ammonia to gas off to atmosphere and be lost as a nutrient. If this reaction is not contained it will also be very smelly! If this emission could be scrubbed with sulphuric acid, then a nice ammonium sulphate fertilizer could be recovered for use in reclamation or for local use thereby displacing fossil fuel generated ammonia fertilizers. About 1 tonne of natural gas needs to be burned to produce 1 tonne of ammonia so this is a nice offset. Ammonia by itself sells for over $1000/tonne. Scrubbing solutions like this are in widespread use and out not expensive. The trouble is in finding a home for the liquid fertilizer especially in non-growing season months.

The lime will also result in the formation of calcium phosphate which is a good plant food.

Lime addition will not necessarily disinfect the sewage but may lower the number of pathogens available.

Overall I think this is a very good project and especially if all production outputs can be consumed locally rather than hauling long distances to be made into compost of negligible value.