The increased automation in carcasses dressing together with the incorporation of washing at every stage (scalding, bleeding, evisceration and tripe treatment) have increased water consumption in slaughterhouse facilities.
Wastewaters are normally subjected to a primary treatment which generally includes the use of screens, settlers and fat separators.
Some slaughterhouse wastewater treatment plants (WWTP) have a secondary anaerobic reactor, usually based on upflow anaerobic sludge blanket (UASB) or expanded granular sludge bed (EGSB) reactor systems, due to the high organic content of the intake.
Several successful experiments at laboratory, pilot and industrial scale with such wastewater and reactor configurations are reported in the literature (Kim and Shin, 2010).
The slaughterhouse also produced other waste streams, such as waste blood, waste from the slaughterhouse wastewater treatment plant (WWTP) and wastewater, which correspond to 82% of total waste production.
The WWTP at the slaughterhouse consisted of a primary treatment facility that included several screens and a dissolved air flotation system (DAF).
Consequently, screened waste and DAF sludge were also considered as waste material flows in the present assays.
Bacterial counts ranged from 4.8 × 10^6 to 5.8 × 10^5 /100 ml of total coliform (TC), 8.2 × 10^4 to 3.2 × 10^4/100 ml of Fecal coliform (FC), 5.2 × 10^4 to 2.0 × 10^4/100 ml of Fecal streptococcus and 1.2 × 10^4 to 2.0 × 10^3/100 ml of Escherichia coli for abattoir effluents.
Pathogens present in animal carcasses or shed in animal wastes may include rotaviruses, hepatitis E virus, Salmonella spp., E. coli O157 : H7, Yersinia enterocolitica, Campylobacter spp., Cryptosporidium parvum, and Giardia lamblia
The average quality of the generated wastewater could be characterised as having a total COD of around 7300 mg dm_3, highly soluble in nature, a low BOD5/COD ratio of 0.44, a significant total N (TKN) concentration of 690mg dm_3 and a total P concentration of only 3.3mg dm_3, very much below the level that would be required to sustain biological treatment.
OPTIMUM PARAMETERS OF THE TREATED WATERS:
Biochemical Oxygen Demand (BOD) and suspended solids of less than 30 mg/L,
Total nitrogen should be less than 15 mg/L and total phosphorus less than 5 mg/L.
Where no direct human contact with the water is anticipated, then the level of thermo-tolerant coliforms can rise to not more than 1,000 per 100 ml.
Dilute SILVCLEAN 10 ml / L and spray liberally on the solid wastes daily and the entire working areas once a week.
Dilute OXIFORTE 2.5 gm/ L and sprinkle liberally on the solid wastes daily and the entire working areas once a week.
Dilute FLYMGTOFF 5 ml / L and spray liberally on the solid wastes daily and the entire working areas once in three days.
Dilute MSW 365 2.5 gm / L and sprinkle liberally on the solid wastes daily and the entire working areas once in 10 days.
USE SILVCLEAN 10 ml / KL / Day
USE OXIFORTE 5 gm / KL / Day
USE SHWWTP 2.5 gm / KL / Day
USE TRIFLOC (PAC, Chitosan and Botanical extract) 1 gm / KL /Day
Slaughterhouse wastewater is very harmful to the environment.
Effluent discharge from slaughterhouses has caused the deoxygenation of rivers (Quinn and Farlane 1989) and the contamination of groundwater (Sangodoyin and Agbawhe 1992).
Blood, one of the major dissolved pollutants in slaughterhouse wastewater, has a chemical oxygen demand (COD) of 375 000 mg/L (Tritt and Schuchardt 1992).
Slaughterhouse wastewater also contains high concentrations of suspended solids (SS), including pieces of fat, grease, hair, feathers, flesh, manure, grit, and undigested feed (Bull et al. 1982).
These insoluble and slowly biodegradable SS represented 50% of the pollution charge in screened (1 mm) slaughterhouse wastewater, while another 25% originated from colloidal solids (Sayed et al. 1988).
VALUE ADDED PRODUCTS FROM THE WASTE
Meat can be rendered into Meat Meal
Bones can be calcined into Calcined Bone Meal
Intestines can be used as Animal Casings
Hair can be used to produce Protein Hydrolysates
Blood can be used to separate Haemoglobin or converted into Blood Meal
Horns and Hooves can be used for making buttons, fertilizers, fire extinguishers etc.
Teeth can be used to prepare Calcium fluoride phosphate.