Bio Means Life

Compost Facility Operations

At the Soil Amendment Facility (SAF), dewatered biosolids are combined with other natural materials like discarded animal bedding and chipped yard trimmings to create a moist, porous mixture.

Special mixing and turning equipment is used to optimize natural aerobic microbial processes, which convert the mixture into a premium quality soil builder. 135%F heat produced by naturally-occurring microbes pasteurizes the material, killing unwanted bacteria and viruses.

After a three-week active composting phase and a three-week curing phase, composted biosolids are screened to remove wood chips, yielding a pleasing, odor-free product.

Using the results of a pilot study conducted in 1990 and 1991, the City developed an in-house computer database system to allow rapid and reliable calculation of biosolids composting mixtures. A companion database management application stores daily compost temperature data, reviews high-temperature exposure and turning history, and produces a report documenting compliance with stringent USEPA requirements for pathogen control and vector attraction reduction.

To protect public health, USEPA regulations also require that composted biosolids meet strict limits for heavy metal content. The Albuquerque Industrial Pretreatment program has been successful in reducing the quantities of heavy metals discharged into the sewers by industries, resulting in declining concentrations of biosolids metals. A monthly composite sample of cured and screened final compost is collected for heavy metals analysis. Results demonstrate that the compost product meets the most stringent USEPA limits for heavy metals content, permitting its unrestricted use for any horticultural purpose.

2008 Affidavit of Compliance [42 KB pdf] with NMDOT Specifications for Compost

Compost Label [118 KB pdf]

Compost Facility Operator certification is a requirement of the NM Solid Waste Management Regulations, and the Water Authority developed an operations training program for its composting personnel. Over a period of eight weeks in 1992, operators attended intensive classroom instruction sessions followed by hands-on practice of acquired knowledge at the PCF. The New Mexico Environment Department awarded certification by reciprocity to Water Authority staff in 1994. Water Authority technical staff continue to assist the NM Environment Department by instructing sessions at Compost Operators' Certification Workshop around the state.