**2. Chemical consumption and generated pollution of modern tanning industry**


Leather is obtained by treating the skin to keep it in good condition. The tanning process consumes a large quantity of chemical products and water according to tanning

#### **Table 1.**

*Quantity of chemicals and water consumed during the treatment of 1000 kilograms bovine hides in tannery.*

*Treatment of Tannery Effluent of Unit Bovine Hides' Unhairing Liming by the Precipitation DOI: http://dx.doi.org/10.5772/intechopen.97657*

type (Traditional or modern). For a modern tannery, the treatment of 1000 kg of bovine hides consumes around 680 kg of chemicals (**Table 1**) and 29 m3 of water. These amounts were used during several operations such as unhairing-liming, rinsing, deliming-bating and chrome tanning; in which 46% of these amounts of chemicals and water were used during correspond unhairing-liming unit (**Table 1**). Otherwise, this tannery rejects around 27 m3 of wastewaters, which is a huge amount. These wastewaters are loaded with excess chemical products, which are not absorbed by skins, and organic matter eliminated from skins during unhairing-liming operation.

## **3. Wastewaters of modern tannery**

A modern tannery was selected to study the quality of tannery wastewater. This industries located in industrial area of Doukkarat in Fez city, Morocco. This latter trait bovine hides only. As mentioned above, the tanning process involves several operations namely unhairing-liming (R1), rinsing (R2), deliming-bating (R3) and chrome tanning (R4) (**Figure 1**). So, the samples of wastewater were collected from the fuller of these units. The samples were monthly collected starting from February 2015. The sampling and conservation conditions were performed according to the ISO 5667-2 standard [25]. The physical parameters: temperature, pH and conductivity were directly measured after sampling. All samples were stored in a refrigerator at a temperature of 4°C according to AFNOR standards set by Rodier [25].
