Don’t Slander the Sludge - Making Good Use of Bad Sludge

Sewage sludge. The mere thought almost puts you off your lunch, doesn’t it? Ah, but convert it to biosolids, and that’s another story! Biosolids are the nutrient-rich organic materials that are left over after the disposed sludge is processed and treated. Biosolids contain nitrogen, phosphorous, potassium (the same ingredients found in chemical fertilizers) as well as magnesium, manganese, iron, zinc and calcium, all of which are desirable components for farmland.

In days gone by, municipalities would deal with their raw sewage by dumping it into a nearby river or lake. Truth be known, this practice still occurs in many areas. More and more municipalities, however, are now required to treat their wastewater, and dispose of the treated byproduct either through recycling it as fertilizer, incinerating it, or burying it in a landfill.

Applied to farmland, biosolids serve many beneficial purposes. The application of biosolids replenishes organic matter which is depleted during the crop cycle, reduces the need for chemical fertilizers, improves crop growth and yields, and reduces production costs of the farmer’s crop. Biosolid application improves soil structure, reduces erosion and runoff, and increases the soil’s capacity to hold water.

The Ministry of Environment and the Ministry of Agriculture, Food and Rural Affairs established guidelines to monitor and control the utilization of biosolids in Ontario that governs the actions of biosolids producers, haulers, and users. Producers must obtain approval of their material before it can be spread on agricultural land. The specific site must be approved and granted a Certificate of Approval. The materials must be shown to be of benefit to crop production or soil health, and not to degrade the natural environment.

Much of the onus is on the treated sewage sludge hauler to meet the guidelines. The hauler and applicator, or biosolids management company, must spread the sewage biosolids at the correct and approved rate, and must comply with separation distances from watercourses, groundwater, bedrock, residences and water wells. Done properly and with due care, recycling biosolids is an excellent use of sewage sludge.

For more information on this article or sewage disposal, visit BartelsEnvironmental.ca