Successful Chrome Precipitation Plant Upgrade for NCMC
The Northern Co-operative Meat Company Ltd, also known as NCMC, is abattoir and tannery located in the NSW Northern Rivers district town of Cassino.
Hydroflux Industrial were contracted to supply and install a completely new chrome precipitation plant that would accept the tanning drum floor wastewater, and general hose down. The system was to remove chrome, from the wastewater along with the suspended solids, in the form of a dewatered sludge, before discharging to the downstream treatment plant located elsewhere on site. The new plant was to not only replace an existing plant, in process, but also the in the same location. This meant that the new plant had to be install in approximately five days during a partial shutdown and with a temporary diversion.
The following process was selected,
- A factory collection pit c/w 316 stainless steel submersible pumps, pumping to a mixed HDPE buffer/balance tank via a Huber RomeshR drum screen.
- From the balance tank effluent is pumped to a mixed HDPE DAF pre-reaction tank (with a retention/reaction time in excess of 30min), where Magnesium Hydroxide was dosed for both pH correction and as a Coagulant.
- The pre-reaction tank gravity flows to a Hydroflux Industrial 316 stainless steel HyDAF HD-20, with polymer addition, from a Hydroflux Industrial Hydroblend polymer system, at the entry of the DAF, to a post DAF discharge pump well for the clarified effluent.
- The DAF removed sludge is pumped to a Hydroflux Industrial, mixed 316 stainless steel conical bottom sludge tank where polymer was added prior to a pair of air operated double diaphragm pumps (AODD) feeding a pair of Hydroflux Industrial CakeMax Chamber Filter Presses.
- Filtrate from the CakeMax CFPs is pumped to the HyDAF discharge tank, whilst the cake solids were conveyed to a solids bin for waste disposal.
The site requirements specified that influent of 500mg/L Chrome had to be reduced to zero in the clarified water, and the incoming Total Suspended Solids (TSS) of approximately 6100mg/L, had to be transported from site as a solids waste of >15% dry solids. The plant achieve results for Chrome too low to detect, and solids cake of 55% dry solids. The site was extremely pleased the Dry Solid level as it significantly reduced the transport and disposal cost, even when compared with the site specification.
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