Wastewater Treatment Basics: What Is Slaughterhouse Wastewater?
Wastewater Treatment Basics: What Is Slaughterhouse Wastewater?
Source and Water Quality of Slaughterhouse Wastewater
Slaughterhouse wastewater comes from pen washing and rinsing, slaughtering and other floor washing, scalding and dehairing, evisceration, by-product processing, oil washing and the like.
From its water-quality sources we can see that the wastewater mainly contains blood, grease, meat scraps, bone residue, hair and feces. The wastewater appears brownish-red and has a strong fishy odor. It is high in organic suspended solids and readily putrefies; if discharged into water bodies it consumes dissolved oxygen, damages ecosystems and pollutes the environment. In addition, its greatest difference from other high-concentration organic wastewaters is its relatively high NH3-N concentration (about 120 mg/L), so the impact of NH3-N on wastewater treatment should be fully considered in process design. [1]
It is characterized by large water volume, uneven discharge, high concentration, and many impurities and suspended solids, with good biodegradability. At the same time, its greatest difference from other high-concentration organic wastewaters lies in its relatively high NH3-N concentration (about 120 mg/L).
During slaughtering and meat processing, large amounts of water are consumed while wastewater containing pollutants such as blood, grease, hair, meat scraps, livestock and poultry viscera, undigested feed and feces is discharged. Such wastewater also contains large numbers of microorganisms harmful to human health. If meat-processing wastewater is discharged without treatment, it causes serious pollution to the water environment and endangers the health of humans and livestock.
Most of the pollutants in meat-processing wastewater are readily biodegradable organics. Once discharged into water bodies they rapidly deplete the dissolved oxygen, causing fish and aquatic organisms to die from oxygen deprivation; the resulting anaerobic state further deteriorates water quality, produces odors and affects sanitation. At the same time, the pathogenic microorganisms in the wastewater multiply in large numbers, endangering public health. Treating slaughterhouse and meat-processing wastewater to remove its pollution is essential for protecting the ecological environment and human health.
The state has promulgated a new technical specification, the "Technical Specification for Engineering of Wastewater Treatment for Slaughtering and Meat Processing" (HJ 2004-2010).
Relevant Standards and Regulations
1. Measures for the Administration of Environmental Protection of Construction Projects (promulgated on 26 March 1986 by the Environmental Protection Commission of the State Council, the State Planning Commission and the State Economic Commission);
2. Regulations on the Administration of Environmental Protection of Construction Projects (adopted at the 10th Executive Meeting of the State Council on 18 November 1998);
3. "Discharge Standard of Water Pollutants for Meat Packing and Processing Industry" (GB 13457-92);
4. "Code for Design of Outdoor Wastewater Engineering" (GB 50014—2006).
Design Principles
5. Strictly implement national and local environmental protection, sanitation and safety regulations; after treatment the main water-quality indicators shall comply with relevant national standards;
6. Adhere to a scientific attitude in design; the wastewater treatment process adopted should be technologically advanced, economically reasonable, mature and safe-reliable, and feature simple operation and convenient operation and management;
7. The treatment units should be relatively compact and occupy as little land as possible; on the premise of ensuring stable operation and compliant effluent, the construction and operating costs should be minimized;
8. In design, adhere to the principle of combining wastewater biological treatment with ecological treatment, so as to create a harmonious wastewater-treatment ecological environment.
Slaughterhouse wastewater is high in organic suspended solids and readily putrefies; if discharged into water bodies it consumes dissolved oxygen, damages ecosystems and pollutes the environment.
