title: Biogas production, sludge accumulation and mass balance of carbon in anaerobic ponds.
abstract: This work concerned the application of anaerobic ponds for the primary treatment of urban wastewater in a Mediterranean climate. It was carried out on anaerobic ponds at large scale in Mèze (France). The anaerobic ponds constitute a good primary treatment with the removal of 55% of SS and 30% of BOD5, with a small surface area. The accumulation rate of sludge was only 0.017 m3/capita.year, due to their intensive anaerobic degradation. The anaerobic digestion reached equilibrium after one year of operation. The accumulation of sludge then showed seasonal variations with a substantial accumulation in winter and the digestion of the stock in summer. This change can be related to the influence of the temperature on methanogenesis. The production of biogas (83% CH4) was measured by gas collectors especially developed for this study and was also strongly dependent on temperature. The mass balance of carbon showed that 74% of the removed organic carbon was converted into CH4, 13% into dissolved inorganic carbon and 15% was stored in sludge. However, the anaerobic ponds presented a risk of creating odor nuisances with the emission of H2S.
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001421:Bacteria, Anaerobic / Q000502:physiology*; D019149:Bioreactors; D002244:Carbon / Q000378:metabolism; D002980:Climate; D005740:Gases; D006862:Hydrogen Sulfide / Q000032:analysis*; D019083:Mediterranean Region; D008697:Methane / Q000032:analysis*; D012722:Sewage / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D000393:Air Pollutants; D005740:Gases; D012722:Sewage; D002244:Carbon; D008697:Methane; D006862:Hydrogen Sulfide