Recycling of Calcium-Silicate Material After Wastewater Filtration to Agriculture - Soil Condition Impact

Abstract

Reactive filter materials aimed at phosphorus (P) recovery is a novel method for on-site wastewater treatment. Once the bed filter is no longer effective, the sorbent must be replaced and can then be recycled as a soil amendment to agriculture. This study investigated the short-term effects of such amendments in a field with a wheat crop in order to evaluate the risks and/or potential benefits of this disposal option. The developed product Polonite (manufactured from Opoka) was used as a model filter sorbent in the field trial. Rates corresponding to approximately 6 and 8 tons per hectare were applied. In the short-term, this amending did not affect soil physical and sorption properties. The rate of Polonite used here, as P source for wheat was irrelevant in this kind of soil. The usefulness of this disposal option of exhausted filter material is discussed.

Performance of an On-Site Wastewater Treatment System Using Reactive Filter Media and a Sequencing Batch Constructed Wetland

“…In the case of Polonite, a system has been developed with P-filter bags that can be replaced when P breakthrough occurs and are transferred to available recycling options. The spent RFM in on-site solutions is not a pure fertilizer that can completely replace commercial fertilizers in agriculture, but it can contribute significantly to soil improvement and plant growth [6].…”