Water saving strategy-Reuse of wastewater
Granarolo is the leading Italian company within the sale of fresh milk and it is one of the market leaders for fresh cheese (3rd largest market share). Granarolo is located in a subsidence area, i.e. an area where there is an excessive withdrawal of ground water. Granarolo used to spend 50% of the water needed from wells and 50% from the aqueduct (data of 2012-2013), with a total amount of around 1 million m3 of water. However, the water consumption decreased to 860,000 m3 and then 600,000 m3 from wells due to the authorized limit.
Today, thanks to the plant of wastewater treatment, water coming from the sedimentation of the purifier is treated through sand filtration (to remove most of the suspended solids) and subsequent ultra filtration to appropriately filter the water sent to final reverse osmosis. Part of this water is sent to the thermal power plant and the rest is mixed with water coming from the ultra filtration in order to obtain a suitable mix to supply the cooling towers. Osmosis and ultra filtration concentrate will then be sent to the purification plant. Thanks to the reuse of wastewater, the water saving rate is equal to 12% compared to the last medium term 60,000 m3 of water are reused every year.
Wastewater could be reused also for other means; however, given the strict prohibition of contact with products, this is not possible. The agri-food sector is indeed a very delicate and high-controlled sector. Water saving rate is 12% compared to the last medium term. The cost of the water used is 2,00 euro per m3, so the money saved through reuse of wastewater is equal to 120,000 euro36.