EVALUATION OF TWO-STAGE SUBSURFACE FLOW CONSTRUCTED WETLANDS FOR ABATTOIR WASTEWATER MANAGEMENT

Abattoir wastewater is high in organic content, the waste recovery and treatment facility is expensive and this results in indiscriminate dumping into streams without adequate treatment. The effectiveness of using a two-stage subsurface flow constructed wetland to treat abattoir effluent was examined in this study. Diluted abattoir wastewater from Lafenwa Abattoir, Abeokuta, Ogun State, Nigeria was fed into a two-stage Vegetated Subsurface Bed Constructed Wetlands (VSBCW). The VSBCW consisted of 500 mm deep 10-15 mm diameter granite with 150 mm thick overlay of well graded sand planted with locally available Vetiveria nigritana. Grab samples were collected at selected points along Ogun river and measurement of physico-chemical parameters such as: Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD5), Electrical Conductivity (EC), Total Dissolved Solids (TDS) and Total Suspended Solid (TSS) of the influent and effluent from the VSBCW were carried out. Irrigation with water and diluted abattoir wastewater to examine the variation in plant growth rate was also investigated. The results revealed a pollution load reduction as the wastewater moves away from the discharge point but inadequate to meet the FEPA (1991) standard for wastewater discharge into rivers. The VSBCW was observed to reduce the concentration of BOD5, COD, EC, TDS and TSS in the abattoir wastewater by 88.71, 87.28, 45.72, 56.89 and 72.27 % respectively. The growth rate of the V. nigritana reduced by 1.9% when irrigated with abattoir wastewater. The study revealed that locally available V. nigritana in VSBCW is effective in abattoir wastewater treatment and could be use to curtail the pollution caused by discharge of untreated wastewater into rivers.

Factorial optimization of Coagulation-Flocculation process for Abattoir Wastewater using Carica Papaya seed extract as bio-coagulant

The objective of this research was to optimize the coagulation-flocculation process for abattoir wastewater by utilizing a bio-coagulant derived from Carica Papaya seed (CPS). The bio-coagulant (CPC) was extracted from the Carica Papaya seed using a 2M NaCl solution, and the coagulation-flocculation process was carried out using a bench scale jar test. Applying design expert (13.0.5.0), 23 full factorials with 5 center points, the effects of three factors: coagulant dosage (X1), pH of the wastewater (X2), and temperature (X3) on turbidity reduction efficiency were examined. Applying ANOVA, it was discovered that a linear model best characterizes the process, with a significant p-value of 0.0015, showing that the model is significant. Additionally, the temperature is a significant component in the model, with a p-value of 0.02 indicating that the temperature is statistically significant. A turbidity reduction efficiency of 90.02 % was attained at the optimum conditions of 0.75g/L of CPC, pH of 6, and temperature of 308 K.

Optimization of hemolysin formation in Alcaligenes species isolated from abattoir wastewater samples in Akure, Ondo State, Nigeria

Hemolysin is significantly toxic and it is used as a molecular marker for pathogenicity. This study evaluates the conditions for optimal hemolysin production by Alcaligenes faecalis strains isolated from a city abattoir wastewater. The parameters investigated for hemolysin formation were size of the inoculum, initial pH of production medium, bacterial incubation temperature, agitation speed and growth media. Thereafter, the effect by various parameter on the hemolytic activity for the formation of hemolysin were assessed. The genus Alcaligenes was assigned to the test organisms after analyzing their 16S rRNA gene sequence with accession numbers: MF498824, MF498825 and MF498827. Optimum conditions for hemolysin formation in Alcaligenes faecalis strain OS42 were inoculum size of 0.5% (v/v), pH 9, 20 oC, 0 rpm and brain heart infusion broth. Hemolytic activities, 77% and 79% were achieved at 20 h for strains OS42 and OS61, respectively. Cholesterol and ethylenediaminetetraacetic acid did not affect hemolysin formation. This work revealed that the hemolysin formation in Alcaligenes strains was sourced from abattoir wastewater effluent and the effluent was contaminated with pathogenic Alcaligenes strains which is a public health hazard due to their prospective infection to human and animal.

Multi-Integrated Systems for Treatment of Abattoir Wastewater: A Review

Biological wastewater treatment processes such as activated sludge and anaerobic digestion remain the most favorable when compared to processes such as chemical precipitation and ion exchange due to their cost-effectiveness, eco-friendliness, ease of operation, and low maintenance. Since Abattoir Wastewater (AWW) is characterized as having high organic content, anaerobic digestion is slow and inadequate for complete removal of all nutrients and organic matter when required to produce a high-quality effluent that satisfies discharge standards. Multi-integrated systems can be designed in which additional stages are added before the anaerobic digester (pre-treatment), as well as after the digester (post-treatment) for nutrient recovery and pathogen removal. This can aid the water treatment plant effluent to meet the discharge regulations imposed by the legislator and allow the possibility for reuse on-site. This review aims to provide information on the principles of anaerobic digestion, aeration pre-treatment technology using enzymes and a hybrid membrane bioreactor, describing their various roles in AWW treatment. Simultaneous nitrification and denitrification are essential to add after anaerobic digestion for nutrient recovery utilizing a single step process. Nutrient recovery has become more favorable than nutrient removal in wastewater treatment because it consumes less energy, making the process cost-effective. In addition, recovered nutrients can be used to make nutrient-based fertilizers, reducing the effects of eutrophication and land degradation. The downflow expanded granular bed reactor is also compared to other high-rate anaerobic reactors, such as the up-flow anaerobic sludge blanket (UASB) and the expanded granular sludge bed reactor (EGSB).

Biosorption of lead by bacteria isolated from abattoir wastewater

Six bacteria were isolated from abattoir wastewater collected from Minna central abattoir. Lead tolerant bacteria were isolated from the wastewater. The isolates were then characterized on the basis of their colonial appearance and reaction to various biochemical tests. The lead tolerance profile of the isolates was carried out using agar diffusion method, with concentrations of Lead nitrate ranging from 50-250 mg/L. Two resistant isolates identified as species of Bacillus and Neisseria were selected for biosorption studies. Lead concentration was determined using Atomic Absorption Spectrophotometry. The lead biosorption capacity of the two isolates was studied by inoculating 2 mL of 24 hours old bacteria suspension in 50mL Nutrient broth, containing varying concentrations of lead (500 and 1000 mg/L) at varying pH (7 and 8), with representative samples being withdrawn at day 4, 8 and 12. The results showed that highest biosorption rate was recorded on day 10, at pH 7, in solution containing 500 mg/L of lead with 75.3% and 66% by Bacillus sp. and Neisseria sp. respectively. These results show that Bacillus sp. had better sorption capacity than Neisseria sp. Both organisms can be used for the removal of lead. Keywords: Wastewater, Biosorption, Abattoir, heavy metal, Bacteria

Molecular Detection of Antibiotic-Resistant Genes in Pseudomonas aeruginosa from Nonclinical Environment: Public Health Implications in Mthatha, Eastern Cape Province, South Africa

Evaluation of resistant profiles and detection of antimicrobial-resistant genes of bacterial pathogens in the nonclinical milieu is imperative to assess the probable risk of dissemination of resistant genes in the environment. This paper sought to identify antibiotic-resistant genes in Pseudomonas aeruginosa from nonclinical sources in Mthatha, Eastern Cape, and evaluate its public health implications. Samples collected from abattoir wastewater and aquatic environment were processed by membrane filtration and cultured on CHROMagarTM Pseudomonas medium. Species identification was performed by autoSCAN-4 (Dade Behring Inc., IL). Molecular characterization of the isolates was confirmed using real-time polymerase chain reaction (rPCR) and selected isolates were further screened for the possibility of harboring antimicrobial resistance genes. Fifty-one Pseudomonas species were recovered from abattoir wastewater and surface water samples, out of which thirty-six strains were Pseudomonas aeruginosa (70.6%). The P. aeruginosa isolates demonstrated resistance to aztreonam (86.1%), ceftazidime (63.9%), piperacillin (58.3%), cefepime (55.6%), imipenem (50%), piperacillin/tazobactam (47.2%), meropenem (41.7%), and levofloxacin (30.6%). Twenty out of thirty-six P. aeruginosa displayed multidrug resistance profiles and were classified as multidrug-resistant (MDR) (55.6%). Most of the bacterial isolates exhibited a high Multiple Antibiotic Resistance (MAR) Index ranging from 0.08 to 0.69 with a mean MAR index of 0.38. In the rPCR analysis of fifteen P. aeruginosa isolates, 14 isolates (93.3%) were detected harboring blaSHV, six isolates (40%) harbored blaTEM, and three isolates (20%) harbored blaCTX-M, being the least occurring ESBL. Results of the current study revealed that P. aeruginosa isolates recovered from nonclinical milieu are resistant to frontline clinically relevant antipseudomonal drugs. This is concerning as it poses a risk to the environment and constitutes a public health threat. Given the public health relevance, the paper recommends monitoring of multidrug-resistant pathogens in effluent environments.

Biodegradation Potential of Abattoir Wastewater Microbiota in Nigeria

Water used for washing carcasses of slaughtered animals and slaughter house is referred to as abattoir wastewater. This study was designed to investigate the microorganisms associated with abattoir wastewater and to establish the biodegradation potential of abattoir wastewater microbiota. Isolation of the microbes was carried out using pour plate technique. The total viable count for the microbes’ ranges from 2.5×104 - 4.6×105 cfu/mL. Results revealed that all the physicochemical parameters exceeded the permissible limits (total dissolved solid (TDS) 1748mg/L, total suspended solid (TSS) 176mg/L, biochemical oxygen demand (BOD5) 91 mg/L and chemical oxygen demand (COD) 227 mg/L). Microorganisms isolated include Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Bacillus anthracis, Aspergillus niger, A. flavus, Mucor sp, Trichophyton quickeanum and Penicillium sp. Some of the microbes were observed to have biodegradation potential by their ability to grow on mineral salt media (MSM) incorporated with starch, cellulose, crude oil, kerosene and diesel as the sole source of carbon and energy. This study suggests that abattoir wastewater harbors microorganisms that could be hazardous to public health when discharged into the environment untreated hence the need for strict monitoring. These microbes isolated could be employed as agent of bioremediation of wastewaters. Key words: Abattoir; Biodegredation; Isolation; Microbiota; Wastewater