Compost, if produced responsibly, is safe and beneficial for the environment.

The guest column on the use of sludge from Kathleen McKee, director of the Maine Toxic Action Committee, was full of misconceptions and bad information (March 31).

First, let’s look at the statement that state law is lax on sludge issues.

As I have worked at municipal composting since 1993 and received my first waste treatment license in 1974, I can tell you we have a long list of items we must comply with.

The compost we produce is independently tested to be sure that it meets the requirements of the law. The final product must meet federal as well as state laws. These include heavy metal limitations as well as microbial limitations, and in each case Maine laws are stricter than federal laws.

The blanket statement that biosolids and compost are the same thing is totally off the mark.

Sludge, or “biosolids,” is the material left over from the wastewater treatment process. In many cases lime is mixed with the sludge to destroy any pathogenic (disease-causing) organisms. This mixture is then spread on farmland, or used in another application. It still resembles sludge in appearance.

Compost, on the other hand, is a process involving the sludge being mixed with an amendment such as wood shavings. This mixture is allowed to reach temperatures in excess of 130 degrees Fahrenheit which kills all microorganisms in the mix. These piles are monitored every day to ensure proper operation.

Finally, the compost is aged a minimum of 21 more days to ensure stability.

As far as sludge being dumped in the ocean and causing dead zones, it wasn’t the toxic nature of the sludge but the decomposing organic material that makes up 75 percent of the sludge. The levels of oxygen in the water dropped below the needed amounts for plants and animals to survive. Any large amount of a decomposing organic would cause the same effect.

As far as the Chinese “night soil” having been safe, that again is not correct.

Today we ensure the pathogenic or disease organisms are killed by heat. In the raw sewage that is spread, as in “night soil,” the material is full of living organisms and is not suitable for use in that form.

As far as metals and bacteria in compost being hazardous, the following data is of interest.

These are actual test results from the Maine Environmental Laboratory in Yarmouth:

• Cadmium in Class A compost is .09 mg/l, in cow manure it’s greater than 5.7mg/l;

• Chromium in Class A compost is 11 mg/l, in cow manure it’s 21 mg/l;

• Lead in Class A compost is 20 mg/l, in cow manure it’s 21mg/l;

• Mercury in Class A compost is 0.53mg/l, in cow manure it’s 0.72 mg/l; and

• Selenium in Class A compost is 0.61 mg/l, in cow manure it’s 0.90 mg/l.

I think it is clear that there is much information out there not based on actual science but based on the old not-in-my-backyard thought process.

Another fact is that compost has to have a bacteria test to show pathogenics are destroyed. Cow manure has more than one can count.

Finally, the assertion that it is the water content that farmers seek is one of the strangest things I’ve heard about compost. There is possibly an additional very small moisture benefit, but the real benefit is that compost has 2 percent nitrogen as well as phosphate and potassium value. It gives clay or sandy soil a beneficial organic boost, as well as a looser soil for root development.

Compost, with no industrial contaminants and produced in a manner that is time tested and proven, is safe and beneficial.

We all produce the raw material and we are responsible for how we deal with it.

We can bury waste in a hole and let our grandchildren wonder at what we’ve given them, or we can use science to show them that something beneficial can be done with anything if it is done properly.

Russ Mathers is superintendent of water and wastewater treatment in Wilton.