A rendering plant that processes four million kilograms of animal waste each week and uses a substantial amount of water and energy for its operations needed to reduce its energy usage.
The exceptionally strong wastewater produced by the business is treated initially in covered anaerobic lagoons (CAL) before being aerobically treated in a sequenced batch reactor (SBR), then flowing to an irrigation dam via a maturation pond. The final effluent is used to irrigate the plant’s own woodlot and pasture land used for cattle grazing.
Removing phosphorous from the effluent was important to ensure pasture uptake capacity is not exceeded. However, only limited phosphorous uptake is achievable within the SBR, resulting in the final effluent exceeding the allowable limit by double. And, the excess phosphorous created a nuisance deposit of struvite resulting in frequent pipe blockages.
In late 2014, the company engaged Calix to dose its anaerobic ponds with ACTI-Mag to allow the pond loadings to be increased from 70 per cent to 100 per cent of the plant’s effluent. ACTI-Mag allowed those loadings to be increased without producing excess acids, which would have caused a detrimental fall in the process pH. This would have compromised the treatment of the wastewater and the business’s ability to generate biogas.
After the dosing, the loading was quickly increased to 100 per cent with an approximate doubling of methane yield for biogas.
Calix was engaged to dose the plant’s anaerobic ponds with ACTI-Mag to help with the treatment of wastewater and the production of biogas
Following the start of the ACTI-Mag dosing, the final effluent phosphorous fell steadily to between 40 and 80 mg/L over six to 12 months. During this period, the reported incidence of struvite pipe blockages also decreased, indicating that nuisance struvite was being reduced.
These positive results encouraged the company to continue using ACTI-Mag to stabilise its process pH, increase biogas production, and lower final effluent phosphorous. Dosing with ACTI-Mag is now an intrinsic part of the wastewater treatment strategy for the business.
As a result of more efficient biogas production, the company has saved approximately $1.5 million on energy costs.
Calix ACTI-Mag can increase the quality and quantity of the biogas coming from anaerobic
systems, and provide a significant economic boost for food processing plants and municipalities.