Water Treatment Plant Filter Cake as Fertilizer

[br1dge]

Quick Question:

I have a neighbor who works at a water plant and has said that he can get me "filter cake" which he said is an incredible fertilizer and expecially here in GA where we have clay. He has said it has great water retention properties and I believe is very close to 30:1 C:N Ratio.


Has anyone ever used this or heard of using this as a fertilizer? Any info on this would be great. I consider myself a pretty decent gardener but by no means an expert. I currently compost and was thinking that this might be another addition to my compost pile or also a soil addition. Thoughts?

 

[mabrungard]

It depends on the treatment operations they perform at that plant. If its a lime softening plant with no alum coagulation, then it might be OK as a soil amendment. The pH of the material might be kind of high though. If its a typical surface water treatment plant with alum coagulation, it might not be a good thing to use. The aluminum sulfate (alum) can build up in your soil and it might become toxic to the plants.

You really have to know what their treatment process is before you can assess if it would be OK to apply to soil.

 

[Jagdad]

I would be wary- most municipal sludge in high in toxic heavy metals.(think mercury, cadmium) Milorganite is a sludge fertilizer from Milwaukee - for years their bags stated no use on edible plants. It took them years to finally removed enough that the gov. OKed it. Another issue is the levels of hormones/ drugs in sludge. Just something to think about . . .

 

[a_potter]

I work at some iron and manganese romoval plants and our waste water sludge has a ton of arcenic in it.

 

[mabrungard]

I assume the OP was referring to water treatment sludge, not wastewater treatment sludge. Heavy metals are not a typical concern in that sludge.

 

[br1dge]

I assume the OP was referring to water treatment sludge, not wastewater treatment sludge. Heavy metals are not a typical concern in that sludge.

Correct. It is a water treatment plant and not a wastewater plant. I have asked about trying to get a report on what exactly is in the sludge. We will see if that comes through. For now I am being very cautious until I can get some concrete answers. My neighbor swears up and down that many people from the plant use it in their home gardens but last thing I want to do is poison my plants. I have a large vegetable garden along with my hops garden and I really dont want to ruin all the work I have put into them both. Thanks for all the responses. I will update the thread as I learn more.

 

[a_potter]

I'm talking about about drinking water filtration backwash. The sludge we get is almost all heavy metals.