Managing agricultural wastewater is critically important due to the high risks it poses to the environment and human health. South Africa’s National Water Act (NWA) of 1998 defines different types of wastewater and the limits thereof via the General Authorisations published under the NWA.
The legislation recognises the following types of wastewater:
| Wastewater | Water containing waste, or water that has been in contact with waste materials. |
| Biodegradable industrial wastewater | Wastewater that contains predominantly organic waste arising from industrial activities and premises including a) milk processing; b) manufacture of fruit and vegetable products; c) sugar mills; d) manufacture and bottling of soft drinks; e) production of alcohol and alcoholic beverages in breweries, wineries or malt houses; f) manufacture of animal feed from plant or animal products; g) manufacture of gelatine and glue from hides, skin and bones; h) abattoirs; i) fish processing; and j) confined animal feeding operations. |
| Complex industrial wastewater | Wastewater arising from industrial activities and premises that contain a) a complex mixture of substances that are difficult or impractical to chemically characterise and quantify; or b) one or more substances for which a waste water limit value has not been specified, and which may be harmful or potentially harmful to human health, or to the water resource. |
| Domestic wastewater | Wastewater arising from domestic and commercial activities and premises, and may contain sewage. |
| Grey water | Wastewater generated through domestic activities and premises, including washing, bathing and food preparation, but does not contain sewage. |
Chemical filling points
At chemical filling points, all wastewater is considered biodegradable industrial wastewater as per the NWA. Furthermore, the legislation implies that the evaporation of wastewater as a method of disposal.
How wastewater is regulated and managed on-site depends on its end use. The table below distinguishes the different thresholds based on the different end-use options for domestic and/or biodegradable industrial wastewater.
| Storage of domestic and biodegradable industrial wastewater for re-use | An owner/lawful occupant may store up to 5,000 m3 of domestic and biodegradable industrial wastewater for the purpose of re-use, given: It does not negatively impact a water resource, or another person’s water use, property, or land; and It is not detrimental to the health and safety of the public. Additionally, if the wastewater if to be re-used for beneficial irrigation, it should comply with the quality parameters set out in tables 1.1 – 1.3 of the general authorisations. |
| Storage of domestic and biodegradable industrial wastewater for disposal | An owner/lawful occupant may store up to: 10,000 m3 per property; or 50,000 m3 in a wastewater pond system per property. Given that the storage of the wastewater: Does not negatively impact a water resource, or another person’s water use, property, or land; and It is not detrimental to the health and safety of the public. |
| Disposal of domestic and biodegradable industrial wastewater | An owner/lawful occupant may dispose of: Up to 1,000 m3 on any given day, given day into: A wastewater pond system; or An evaporation pond system Additionally, if the wastewater is being disposed of via discharge into a water source, it should comply with the quality parameters set out in Table 2.1 of the general authorisations. |
Note that evaporation pits cannot exceed 10,000 m3 due to the maximum storage thresholds. However, larger pits may still only dispose of 1,000 m3 per day, and accurate records must be kept.
Biodegradable industrial wastewater: when is a water-use license required?
A water-use license is required for:
- The disposal of more than 50 m3 of domestic or biodegradable industrial wastewater per day.
- The storage of more than 1,000 m3 of domestic or biodegradable industrial wastewater for disposal.
- The storage of more than 500 m3 of domestic or biodegradable industrial wastewater for re-use.
Packhouse wastewater
Although packhouse wastewater is generated differently than wastewater from a chemical filling point, both are legally classified as biodegradable industrial wastewater and should, therefore, be treated and managed in the same manner.
Sewage wastewater
Sewage wastewater is managed differently to biodegradable industrial wastewater. The management of sewage is governed by the NWA, the Water Services Act (WSA) of 1998, and SANS 10400-P. Some requirements include:
- All excreta containments (i.e., pit latrines, soakaway pits, etc) must be at least 50 meters away from groundwater resources and at least 1.5 meters above the water table.
- A conservancy tank or septic tank must be used to receive sewage, and thereafter, the remaining effluent may be discharged into a French drain.
- Conform to the context-specific dimensions in SANS 10400-P.
Overall, when managing agricultural wastewater on-site, it is paramount to identify the type of wastewater being managed and its end-use to determine the correct requirements and legislation to comply with.
