1
|
Amarilla MS, Glienke L, Munduruca Pires T, Sobarzo CM, Oxilia HG, Fulco MF, Rodríguez Peña M, Maio MB, Ferrer Viñals D, Lustig L, Jacobo PV, Theas MS. Impaired Spermatogenesis in Infertile Patients with Orchitis and Experimental Autoimmune Orchitis in Rats. Biology (Basel) 2024; 13:278. [PMID: 38666890 PMCID: PMC11048156 DOI: 10.3390/biology13040278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 04/10/2024] [Accepted: 04/12/2024] [Indexed: 04/28/2024]
Abstract
Experimental autoimmune orchitis (EAO) is a well-established rodent model of organ-specific autoimmunity associated with infertility in which the testis immunohistopathology has been extensively studied. In contrast, analysis of testis biopsies from infertile patients associated with inflammation has been more limited. In this work, testicular biopsies from patients with idiopathic non-obstructive azoospermia diagnosed with hypospermatogenesis (HypoSp) [mild: n = 9, and severe: n = 11], with obstructive azoospermia and complete Sp (spermatogenesis) (control group, C, n = 9), and from Sertoli cell-only syndrome (SCOS, n = 9) were analyzed for the presence of immune cells, spermatogonia and Sertoli cell (SCs) alterations, and reproductive hormones levels. These parameters were compared with those obtained in rats with EAO. The presence of increased CD45+ cells in the seminiferous tubules (STs) wall and lumen in severe HypoSp is associated with increased numbers of apoptotic meiotic germ cells and decreased populations of undifferentiated and differentiated spermatogonia. The SCs showed an immature profile with the highest expression of AMH in patients with SCOS and severe HypoSp. In SCOS patients, the amount of SCs/ST and Ki67+ SCs/ST increased and correlated with high serum FSH levels and CD45+ cells. In the severe phase of EAO, immune cell infiltration and apoptosis of meiotic germ cells increased and the number of undifferentiated and differentiated spermatogonia was lowest, as previously reported. Here, we found that orchitis leads to reduced sperm number, viability, and motility. SCs were mature (AMH-) but increased in number, with Ki67+ observed in severely damaged STs and associated with the highest levels of FSH and inflammatory cells. Our findings demonstrate that in a scenario where a chronic inflammatory process is underway, FSH levels, immune cell infiltration, and immature phenotypes of SCs are associated with severe changes in spermatogenesis, leading to azoospermia. Furthermore, AMH and Ki67 expression in SCs is a distinctive marker of severe alterations of STs in human orchitis.
Collapse
Affiliation(s)
- María Sofía Amarilla
- Instituto de Investigaciones Biomédicas (INBIOMED), CONICET-Universidad de Buenos Aires, Paraguay 2155, Piso 10, Laboratorio 10, Ciudad Autónoma de Buenos Aires C1421ABG, Argentina; (L.G.); (T.M.P.); (C.M.S.); (M.B.M.); (D.F.V.); (L.L.)
| | - Leilane Glienke
- Instituto de Investigaciones Biomédicas (INBIOMED), CONICET-Universidad de Buenos Aires, Paraguay 2155, Piso 10, Laboratorio 10, Ciudad Autónoma de Buenos Aires C1421ABG, Argentina; (L.G.); (T.M.P.); (C.M.S.); (M.B.M.); (D.F.V.); (L.L.)
- Departamento de Biología Celular, Facultad de Medicina, Universidad de Buenos Aires, Cátedra II de Histología, Paraguay 2155, Ciudad Autónoma de Buenos Aires C1421ABG, Argentina;
| | - Thaisy Munduruca Pires
- Instituto de Investigaciones Biomédicas (INBIOMED), CONICET-Universidad de Buenos Aires, Paraguay 2155, Piso 10, Laboratorio 10, Ciudad Autónoma de Buenos Aires C1421ABG, Argentina; (L.G.); (T.M.P.); (C.M.S.); (M.B.M.); (D.F.V.); (L.L.)
- Departamento de Biología Celular, Facultad de Medicina, Universidad de Buenos Aires, Cátedra II de Histología, Paraguay 2155, Ciudad Autónoma de Buenos Aires C1421ABG, Argentina;
| | - Cristian Marcelo Sobarzo
- Instituto de Investigaciones Biomédicas (INBIOMED), CONICET-Universidad de Buenos Aires, Paraguay 2155, Piso 10, Laboratorio 10, Ciudad Autónoma de Buenos Aires C1421ABG, Argentina; (L.G.); (T.M.P.); (C.M.S.); (M.B.M.); (D.F.V.); (L.L.)
- Departamento de Biología Celular, Facultad de Medicina, Universidad de Buenos Aires, Cátedra II de Histología, Paraguay 2155, Ciudad Autónoma de Buenos Aires C1421ABG, Argentina;
| | - Hernán Gustavo Oxilia
- Departamento de Biología Celular, Facultad de Medicina, Universidad de Buenos Aires, Cátedra II de Histología, Paraguay 2155, Ciudad Autónoma de Buenos Aires C1421ABG, Argentina;
- Anatomía Patológica, Hospital General de Agudos Parmenio Piñero, Varela 1301, Ciudad Autónoma de Buenos Aires C1406ELA, Argentina
| | - María Florencia Fulco
- Hospital de Clínicas General San Martín, Av. Córdoba 2351 (C1120AAR), Ciudad Autónoma de Buenos Aires C1421ABG, Argentina; (M.F.F.); (M.R.P.)
| | - Marcelo Rodríguez Peña
- Hospital de Clínicas General San Martín, Av. Córdoba 2351 (C1120AAR), Ciudad Autónoma de Buenos Aires C1421ABG, Argentina; (M.F.F.); (M.R.P.)
| | - María Belén Maio
- Instituto de Investigaciones Biomédicas (INBIOMED), CONICET-Universidad de Buenos Aires, Paraguay 2155, Piso 10, Laboratorio 10, Ciudad Autónoma de Buenos Aires C1421ABG, Argentina; (L.G.); (T.M.P.); (C.M.S.); (M.B.M.); (D.F.V.); (L.L.)
| | - Denisse Ferrer Viñals
- Instituto de Investigaciones Biomédicas (INBIOMED), CONICET-Universidad de Buenos Aires, Paraguay 2155, Piso 10, Laboratorio 10, Ciudad Autónoma de Buenos Aires C1421ABG, Argentina; (L.G.); (T.M.P.); (C.M.S.); (M.B.M.); (D.F.V.); (L.L.)
| | - Livia Lustig
- Instituto de Investigaciones Biomédicas (INBIOMED), CONICET-Universidad de Buenos Aires, Paraguay 2155, Piso 10, Laboratorio 10, Ciudad Autónoma de Buenos Aires C1421ABG, Argentina; (L.G.); (T.M.P.); (C.M.S.); (M.B.M.); (D.F.V.); (L.L.)
- Departamento de Biología Celular, Facultad de Medicina, Universidad de Buenos Aires, Cátedra II de Histología, Paraguay 2155, Ciudad Autónoma de Buenos Aires C1421ABG, Argentina;
| | - Patricia Verónica Jacobo
- Instituto de Investigaciones Biomédicas (INBIOMED), CONICET-Universidad de Buenos Aires, Paraguay 2155, Piso 10, Laboratorio 10, Ciudad Autónoma de Buenos Aires C1421ABG, Argentina; (L.G.); (T.M.P.); (C.M.S.); (M.B.M.); (D.F.V.); (L.L.)
- Departamento de Biología Celular, Facultad de Medicina, Universidad de Buenos Aires, Cátedra II de Histología, Paraguay 2155, Ciudad Autónoma de Buenos Aires C1421ABG, Argentina;
| | - María Susana Theas
- Instituto de Investigaciones Biomédicas (INBIOMED), CONICET-Universidad de Buenos Aires, Paraguay 2155, Piso 10, Laboratorio 10, Ciudad Autónoma de Buenos Aires C1421ABG, Argentina; (L.G.); (T.M.P.); (C.M.S.); (M.B.M.); (D.F.V.); (L.L.)
- Departamento de Biología Celular, Facultad de Medicina, Universidad de Buenos Aires, Cátedra II de Histología, Paraguay 2155, Ciudad Autónoma de Buenos Aires C1421ABG, Argentina;
| |
Collapse
|
2
|
Madera-Parra CA, Peña MR, Peña EJ, Lens PNL. Cr(VI) and COD removal from landfill leachate by polyculture constructed wetland at a pilot scale. Environ Sci Pollut Res Int 2015; 22:12804-12815. [PMID: 25253061 DOI: 10.1007/s11356-014-3623-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 09/16/2014] [Indexed: 06/03/2023]
Abstract
Four subsurface horizontal-flow constructed wetlands (CWs) at a pilot scale planted with a polyculture of the tropical plants Gynerium sagittatum (Gs), Colocasia esculenta (Ce) and Heliconia psittacorum (He) were evaluated for 7 months. The CW cells with an area of 17.94 m(2) and 0.60 m (h) each and 0.5 m of gravel were operated at continuous gravity flow (Q = 0.5 m(3) day(-1)) and a theoretical HRT of 7 days each and treating landfill leachate for the removal of filtered chemical oxygen demand (CODf), BOD5, TKN, NH4 (+), NO3 (-), PO4 (3-)-P and Cr(VI). Three CWs were divided into three sections, and each section (5.98 m(2)) was seeded with 36 cuttings of each species (plant density of six cuttings per square metre). The other unit was planted randomly. The final distributions of plants in the bioreactors were as follows: CW I (He-Ce-Gs), CW II (randomly), CW III (Ce-Gs-He) and CW IV (Gs-He-Ce). The units received effluent from a high-rate anaerobic pond (BLAAT®). The results show a slightly alkaline and anoxic environment in the solid-liquid matrix (pH = 8.0; 0.5-2 mg L(-1) dissolved oxygen (DO)). CODf removal was 67 %, BOD5 80 %, and TKN and NH4 (+) 50-57 %; NO3 (-) effluents were slightly higher than the influent, PO4 (3-)-P (38 %) and Cr(VI) between 50 and 58 %. CW IV gave the best performance, indicating that plant distribution may affect the removal capacity of the bioreactors. He and Gs were the plants exhibiting a translocation factor (TF) of Cr(VI) >1. The evaluated plants demonstrated their suitability for phytoremediation of landfill leachate, and all of them can be categorized as Cr(VI) accumulators. The CWs also showed that they could be a low-cost operation as a secondary system for treatment of intermediated landfill leachate (LL).
Collapse
Affiliation(s)
- C A Madera-Parra
- EIDENAR School, Universidad del Valle, AA, 25360, Cali, Colombia,
| | | | | | | |
Collapse
|
3
|
Madera-Parra CA, Peña-Salamanca EJ, Peña MR, Rousseau DPL, Lens PNL. Phytoremediation of Landfill Leachate with Colocasia esculenta, Gynerum sagittatum and Heliconia psittacorum in Constructed Wetlands. Int J Phytoremediation 2015; 17:16-24. [PMID: 25174421 DOI: 10.1080/15226514.2013.828014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This study assessed the accumulation of Cd (II), Hg (II), Cr (VI) and Pb (II) in Gynerium sagittatum (Gs), Colocasia esculenta (Ce) and Heliconia psittacorum (He) planted in constructed wetlands treating synthetic landfill leachate. Sixteen bioreactors were operated in two experimental blocks. Metal concentrations in the influent and effluent; root, stem, branch and leaves of plants were analysed, as well as COD, N-NH4+, TKN, T, pH, ORP, DO, and EC. Average removal efficiencies of COD, TKN and NH4+-N were 66, 67 and 72%, respectively and heavy metal removal ranged from 92 to 98% in all units. Cr (VI) was not detected in any effluent sample. The bioconcentration factors (BCF) were 10(0) -10(2). The BCF of Cr (VI) was the lowest: 0.59 and 2.5 (L kg(-1)) for Gs and He respectively; whilst Cd (II) had the highest (130-135 L kg(-1)) for Gs. Roots showed a higher metal content than shoots. Translocation factors (TF) were lower, He was the plant exhibiting TFs>1 for Pb (II), Cr (T) and Hg (II) and 0.4-0.9 for Cd (II) and Cr (VI). The evaluated plants demonstrate their suitability for phytoremediation of landfill leachate and all of them can be categorized as metals accumulators.
Collapse
|
4
|
Peña MR, Aponte A, Toro AF. Start-up and maturation phases of a full-scale, high-rate anaerobic pond bioreactor(®) plus improved facultative ponds to treat municipal wastewater. Water Sci Technol 2015; 71:503-510. [PMID: 25746640 DOI: 10.2166/wst.2015.041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Results of the start-up and maturation phases of a full-scale, high-rate anaerobic pond bioreactor (HRAPB)(®) plus improved facultative ponds (IFPs) to treat municipal wastewater are presented (CODt: 759 mg L⁻¹, CODf: 219 mg L⁻¹, S-SO(4)(2-): 102 mg L⁻¹, and Cr⁺: 1,500 μgL⁻¹). The start-up of the HRAPB(®) comprised, first, the application of a selective pressure increasing up-flow velocity rates. Second, batch stages between successive rates were allowed until 70% of the initial CODf was removed. The IFPs were left in batch and ended when in-pond Chlorophyll-a concentration reached 800 μgL⁻¹. Subsequently, the system underwent gradual maturation and reached effluent concentrations of CODt: 223 mg L⁻¹, CODf: 50 mg L⁻¹, and Cr⁺: 60 μgL⁻¹. The actual efficiency of the system compared with the expected design efficiency was lower given the characteristics of the influent wastewater biochemical oxygen demand/chemical oxygen demand ratios < 0.4, presence of Cr⁺ >1,000 μgL⁻¹, and variations in both conductivity (500-4,500 μScm⁻¹) and pH (6.5-10.5 units). Nonetheless, the system exhibited an adaptation state in less than 1.5 months and yielded an ST/SV ratio of 0.46, and specific methanogenic activity of 0.43 g-CH4-CODg⁻¹SV⁻¹d⁻¹ for HRAPB(®); the in-pond Chlorophyll-a was on average 1,200 μgL⁻¹ in the IFPs, which demonstrated the robustness of these eco-technologies in tropical conditions.
Collapse
Affiliation(s)
- M R Peña
- Universidad del Valle, Environmental Sanitation Research Group at Cinara Institute, A.A. 25157 Cali, Colombia E-mail:
| | - A Aponte
- Universidad del Valle, Environmental Sanitation Research Group at Cinara Institute, A.A. 25157 Cali, Colombia E-mail:
| | - A F Toro
- Universidad del Valle, Environmental Sanitation Research Group at Cinara Institute, A.A. 25157 Cali, Colombia E-mail:
| |
Collapse
|
5
|
Peña MR, Mara DD, Avella GP. Dispersion and treatment performance analysis of an UASB reactor under different hydraulic loading rates. Water Res 2006; 40:445-52. [PMID: 16405944 DOI: 10.1016/j.watres.2005.11.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2003] [Revised: 11/01/2005] [Accepted: 11/08/2005] [Indexed: 05/06/2023]
Abstract
Mixing and transport phenomena affect the efficiency of all bioreactor configurations. An even mixing pattern at the macro-level is desirable to provide good conditions for substrate transport to, and from, the microbial aggregates. The state of segregation of particulate material in the reactor is also important. The production of biogas in anaerobic reactors is another factor that affects mixing intensity and hence the interactions between the liquid, solid and gaseous phases. The CSTR model with some degree of short-circuiting, dead zones and bypassing flows seems to describe the overall hydrodynamics of UASBs. However, few data are available in the literature for full-scale reactors that relate process performance to mixing characteristics. Dispersion studies using LiCl were done for four hydraulic loading rates on a full-scale UASB treating domestic wastewater in Ginebra, Valle del Cauca, southwest Colombia. COD, TSS, and Settleable Solids were used to evaluate the performance of organic matter removal. The UASB showed a complete mixing pattern for hydraulic loading rates close to the design value (i.e. Q = 10-13l s(-1) and HRT=8-6 h). Gross mixing distortions and localised stagnant zones, short-circuiting and bypass flows were found in the sludge bed and blanket zones for both extreme conditions (underloading and overloading). The liquid volume contained below the gas-liquid-solid separator was found to contribute to the overall stagnant volume, particularly when the reactor was underloaded. The removal of organic matter showed a log-linear correlation with the dispersion number.
Collapse
Affiliation(s)
- M R Peña
- Instituto Cinara, Universidad del Valle, A.A 25157, Cali, Valle del Cauca, Colombia.
| | | | | |
Collapse
|
6
|
Peña MR, Mara DD, Piguet JM. Improvement of mixing patterns in pilot-scale anaerobic ponds treating domestic sewage. Water Sci Technol 2003; 48:235-242. [PMID: 14510216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Anaerobic ponds are customarily designed as completely mixed reactors. However, evidence from experiments on full-scale facilities shows large deviations from ideal flow models, which in turn cause a reduced process performance. Thus, modified pilot scale anaerobic ponds receiving domestic sewage were developed and studied in parallel. A factorially designed experiment evaluated horizontal and vertical baffling, ponds fitted with cross-sectional plastic nets and a pond with a mixing pit. The hydrodynamic behaviour and process performance of these modified configurations were monitored for four flow rates (1.0, 1.2, 1.5 and 2.0 l/s). The results showed that baffling (vertical and horizontal) and the mixing pit configuration had the best hydrodynamic behaviours and removal efficiencies. Consequently, the development of high-rate anaerobic ponds, through improvements of hydrodynamic behaviour, seems feasible.
Collapse
Affiliation(s)
- M R Peña
- Universidad del Valle, Instituto Cinara A.A 25157, Cali, Colombia
| | | | | |
Collapse
|
7
|
Vega GP, Peña MR, Ramírez C, Mara DD. Application of CFD modelling to study the hydrodynamics of various anaerobic pond configurations. Water Sci Technol 2003; 48:163-171. [PMID: 14510207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The simulation of hydrodynamics and transport phenomena in waste stabilization ponds is a developing tool worth studying in order to understand their internal processes and interactions. Pond design involves several physical, hydrological, geometric and dynamic variables so as to provide high hydrodynamic efficiency and maximum substrate utilization rates. CFD modelling allows the combination of these factors to predict the behaviour of ponds having different configurations. The two-dimensional depth-integrated model MIKE 21 was used in this study to simulate hydrodynamic and advection-dispersion processes in a full-scale anaerobic pond (AP) located in southwest Colombia. A set of 12 configurations including sludge contents, inlet-outlet positioning, baffling and pond geometry were modelled. Results showed that a crosswise (diagonally opposite) inlet-outlet layout, a length-to-breadth ratio of 2:1, plus provision of two cross baffles at 1/3 L and 2/3 L were the most effective measures to improve overall AP hydrodynamics and dispersion patterns.
Collapse
Affiliation(s)
- G P Vega
- Universidad del Valle, Instituto Cinara A.A 25157, Cali, Colombia
| | | | | | | |
Collapse
|
8
|
Peña MR, Madera CA, Mara DD. Feasibility of waste stabilization pond technology for small municipalities in Colombia. Water Sci Technol 2002; 45:1-8. [PMID: 11833722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The selection of any wastewater treatment technology should take into consideration both "software" and "hardware" aspects. There are contrasting opinions regarding the feasibility of waste stabilisation ponds (WSP): some emphasise their advantages while others are concerned with their high land area requirements. As with any technology, WSP are feasible under specific circumstances related to the context where they are to be implemented. In this study data were collected from three regions in Colombia (Nariño, Tolima and Valle del Cauca) in order to assess the feasibility of WSP under real conditions in a tropical country. A feasibility matrix was developed in order to organise and synthesise the information gathered. The results obtained showed that WSP are highly feasible in Tolima and Valle del Cauca due to the fact that these regions have geographical, socio-economic and technical characteristics that enhance the advantages of WSP technology. Nariño has a very mountainous topography along with other local limitations that hinder the application of WSP technology. The cost of land was not found to be a real limitation for the technology, whereas the availability of land is. Finally, the feasibility matrix may be a good planning tool at regional or national levels in order to help decision-making regarding cost-effective wastewater treatment alternatives on the basis of local conditions.
Collapse
Affiliation(s)
- M R Peña
- Instituto Cinara, Univalle, Cali, Colombia
| | | | | |
Collapse
|
9
|
Madera CA, Peña MR, Mara DD. Microbiological quality of a waste stabilization pond effluent used for restricted irrigation in Valle Del Cauca, Colombia. Water Sci Technol 2002; 45:139-143. [PMID: 11833728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This paper discusses the applicability of effluent reuse in agriculture after treatment in a series of anaerobic, facultative and maturation ponds. The WSP system is located in Ginebra municipality, a small town in southwest Colombia. The total HRT is 12 days. Several samples of the final effluent were taken over a 55 day period and were analysed for E. coli, Streptococcus spp. and helminth eggs. Some additional grab samples were taken to determine the presence of pathogenic bacteria such as Salmonella spp. and Shigella spp. The results showed that the system was able to remove 4 log units of E. coli, 1 log unit of Streptococcus spp. and 100% of helminth eggs. Meanwhile, Salmonella spp. were detected in the effluent of the facultative pond whilst Shigella spp. were not detected in any sample. The main species of helminth eggs encountered were Taenia spp., Ascaris spp., Trichuris spp., Hymenolepis nana, H. diminuta and Enterobius vermicularis. Removal efficiencies were satisfactory despite the relatively short HRT. Nevertheless, WHO guidelines were slightly surpassed in the case of E. coli for unrestricted irrigation. The helminth egg value was always below the maximum WHO limit. Hence, this effluent can be safely used for restricted irrigation provided that field workers are protected from direct contact with wastewater given the presence of Salmonella spp. in the facultative pond effluent.
Collapse
Affiliation(s)
- C A Madera
- Instituto Cinara, Univalle, Cali, Colombia
| | | | | |
Collapse
|
10
|
Rodríguez JA, Peña MR, Manzi V. Application of an innovative methodology to improve the starting-up of UASB reactors treating domestic sewage. Water Sci Technol 2001; 44:295-303. [PMID: 11575096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This study shows the results obtained during the starting-up evaluation of an UASB reactor treating domestic sewage. It is located in the municipality of Ginebra, Valle del Cauca region in Colombia. Its design flow is 7.5 l/s with a maximum capacity of 10 l/s. The reactor was seeded with a deficient quality inoculum which accounted for 20% of the total reactor volume. The starting-up methodology comprised the sequential washing of the sludge (inoculum) by applying three different upflow velocities. This procedure resembles what other authors term the "selective pressure method". Once the sludge was washed, the reactor was started-up with an initial hydraulic retention time (HRT) of 24.9 hours, which was steadily reduced down to 6.7 hours in the final stage. Along the starting-up phase, there was a positive evolution in terms of quantity, quality and spatial distribution of the sludge. Consequently, there was a positive evolution in organic matter removal mechanisms. For HRT above 14 hours, the removal mechanisms were mainly physical whilst for HRT below 9 hours the removal mechanisms were mostly biological. Based on the above considerations and on the water quality parameters measured, it may be concluded that the start-up of an UASB reactor for domestic sewage treatment seeded with a low quality inoculum can be done with HRT as low as 15 or 12 hours. In this way, it is possible to reduce the starting-up period of these reactors down to 4 to 6 weeks, provided that the starting-up methodology is properly applied.
Collapse
Affiliation(s)
- J A Rodríguez
- Instituto Cinara, Univalle, A.A. 25157, Cali, Valle, Colombia
| | | | | |
Collapse
|