Client: ANZCO Meats
Commissioning Date: July 2013
Population Equivalent: 2,700
Flow Rate: 510m3/day (average dry- weather flow)
ANZCO Meats Wastewater Treatment Plant
ANZCO Meats is situated in the North Island township of Bulls. Like most meat processing plants, ANZCO’ output doubles during the peak season. Our task was to design and build a biological nitrogen reduction system that used as much of the existing plant as possible.
Description
The waste stream from beef processing plants is typically elevated in biochemical oxygen demand (BOD) with the fractionation of ammonia and phosphorus being higher than standard municipal wastewater. The waste from the Bulls plant first passes through an anaerobic digestion pond that has a natural fatty cake formed on the surface. The digestion in this first pond is very beneficial as the BOD reduction is efficient, leaving the remainder of the treatment chain to focus on nutrient reduction. Pond 2 is a standard aerated lagoon focusing on further BOD reduction and the beginning of the nitrification and facultative processes.
A design incorporating floating treatment media and geo-synthetic baffles with oxygenation and circulation is located on Pond 3. This stage is a nitrification stage that also has areas of simultaneous denitrification occurring. The final pond is covered by floating treatment media providing anoxic conditions for final denitrification. The plant roots act as a biomechanical filter entrapping the total suspended solids (TSS) within the root zones producing a clean compliant effluent.
Benefits
This project demonstrates the cost effectiveness of floating treatment media. The FTM was retrofitted to the existing treatment pond. This saved ANZCO Meats capital expenditure as no additional land or civil construction was required. The plant is able to remain under the same management structure as prior to the upgrade. Also, further tertiary and primary treatment can be incorporated into the design to treat other parameters.
| Parameter | Avg (mg/L) | Max (mg/L) |
|---|---|---|
| BOD | 350 | – |
| TSS | 500 | – |
| TKN | 55 | – |
| NH4N | 46 | 116 |
| DRP | 28 | 35 |
| Tmin | 15°C | 15°C |
| Tmax | 25°C | 25°C |
| Flow Data | ||
| ADWF – 2014 | 510m3/d |
| Parameter | Avg (mg/L) | Consent |
|---|---|---|
| BOD | 6 | Under Review |
| TSS | 50 | |
| TKN | – | |
| NH4N | 5.2 | |
| DRP | 21 | |
| E Coli | – |
