Meeting strict discharge consent
Dairy manufacturer in Southland, New Zealand
Following a site expansion, a dairy site in the Southland region needed to upgrade their wastewater treatment (WWTP) plant to achieve higher quality treatment with increased discharge volumes of dairy plant effluent. The dairy waste is required to reach a standard where it could be either discharged to a river or used for irrigation. As part of an environmental initiative from the customer’s international headquarters, sludge produced by the plant was to be dewatered, while the treated effluent was required to meet their own standards, which had stricter parameters than the regional council’s discharge consent requirements.
What We Did
FILTEC was awarded the project as head contractor to build the wastewater treatment plant, spanning from initial design to hand over. To meet strict discharge requirements, FILTEC’s design included a Nijhuis dissolved air flotation system (DAF) followed by a modified Ludzack-Ettinger (MLE) system with the addition of alum dosing for total phosphorus removal. It also included all ancillary systems, such as chemical dosing for pH correction, coagulation, flocculation and sludge dewatering and disposal. The installation of sludge handling and dewatering facilities reduce plant operational costs in the disposal of sludge.
Despite the extremely high raw influent nutrient load delivered to the plant throughout commissioning and performance testing, the WWTP showed exceptional successful results, with an average removal of 98%. Moreover, the implemented sludge storage system provided the customer with the flexibility of dewatering DAF sludge only, waste activated sludge only, or a combination of both, resulting in a valuable biomass opportunity.