Christchurch City Council Seeks Proposals for Biosolids Beneficial Reuse

Sewage produced from Christchurch City is treated at the Christchurch Wastewater Treatment Plant at Bromley. As part of the treatment process, dried Biosolids is produced at a rate of approximately 10 tons per day. The Biosolids are regularly collected by external parties under contract, who take the Biosolids to other sites where it is beneficially re-used.

Biosolids have valuable fertilising and soil conditioning properties. They contain micronutrients and organic material and, worldwide, they are commonly applied to land as a means of restoring degraded soils or boosting the productivity of soils within areas of low natural fertility.

Examples of beneficial use include the restoration of depleted cropping soils, maintenance or enhancement of soil fertility in forests, rehabilitation of mine tailings and quarry sites, landfill cover, golf courses, parks and gardens. The application of Biosolids to land can be controversial.

Biosolids contain microbiological and chemical contaminants, and there are legitimate concerns about public health, environmental and economic risks. There are also numerous alternative beneficial re-uses of Biosolids, for example energy extraction and inclusion in aggregates. Council requires that the Biosolids produced are beneficially re-used and are NOT sent to landfill. Due to downtime on the sludge dryer (i.e.

planned and reactive maintenance), Council also requires the collection and beneficial reuse of approximately 800 t of Wet Biosolids a year. In accordance with Annexure 2 - Dried Biosolids Guidelines, Biosolids must be delivered to a consented facility or comply with Annexure 6 - HAIL and District Plan Effects.

The purpose of this RFP is to invite Prospective Suppliers to submit their Proposals for Biosolids Beneficial Reuse.