Wastewater stabilisation ponds: Sludge accumulation, technical and financial study on desludging and sludge disposal case studies in France.

Waste stabilisation pond treatment was widely developed during the 1980s in France, where there are now over 3,000 plants. Desludging the ponds has now become essential. In 19 primary facultative ponds, in operation for 12-24 years, the net average sludge accumulation rate was 19 mm/yr.

Biogas production, sludge accumulation and mass balance of carbon in anaerobic ponds.

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.

Emission of H2S and mass balance of sulfur in anaerobic ponds.

Anaerobic ponds are highly efficient at removing BOD from wastewater with a reduced land area requirement. However, their use is often limited because of the problem of odor release, primarily due to the emission of hydrogen sulfide (H2S). The experiments were conducted on full scale anaerobic ponds used for the primary treatment of urban wastewater under Mediterranean climatic conditions (south of France).

Influence of load distribution and recycle rate in step-fed facultative ponds.

This study presents the results of research on a wastewater treatment system with four identical facultative ponds in series with step-feeding and recirculation (SFFPR). Four modes of distribution of the influent were studied, which were (in percentages of the inflow per pond): C1 = 25/25/25/25; C2 = 50/20/20/10; C3 = 50/50/0/0; C4 = 100/0/0/0. The organic loading applied to the four ponds overall was around 200 kg BOD5/ha.

Odor control of an anaerobic lagoon with a biological cover: floating peat beds.

The use of a biological cover for in situ control of gaseous sulfide emission from an anaerobic pond was investigated by a laboratory-scale experiment. The biological cover, constituting by a peat bed floating on the wastewater, caused a reduction of the H2S emission rate by 84.6%.