Removing hydrogen sulfide from water with air oxygen
by the method of «dry» filtration in anthracite media

Summary

One of the causes that limit the widespread use of artesian waters is the presence of hydrogen sulfide. The method of removing hydrogen sulfide from water by converting the ionic forms HS^- and S^2- into molecular H₂S (acidification of water to pH ≤ 5) with subsequent degassing is not environmentally friendly due to air pollution with hydrogen sulfide blown away in the degasser. Oxidation of hydrogen sulfide to elemental sulfur or its oxides is carried out with the use of expensive oxidants that while being applied require special safety measures. An effective chemical free method of removing hydrogen sulfide from water can be the use of an oxidizing filter consisting of a sealed housing partially filled with non-submerged catalytic electrically conductive anthracite media with a grain size of 0.8–2 mm. Air is injected into the distribution perforated water feeding system located above the media. Herewith, the tightness of the filter eliminates the emission of hydrogen sulfide into the atmosphere and pollution of the room, whereas the entire volume of the catalytic media is residing in an oxygen-containing environment in the most active mode of catalytic oxidation of hydrogen sulfide. Purified water is collected at the bottom of the filter in a collector with an air outlet connected to it. After 2–4 days of operation, the filter is removed from the filtration mode to regenerate the catalytic media by back air washing with the removal of elemental sulfur S⁰ formed during the oxidation of hydrogen sulfide.

Key words

liquid-phase oxidation , «dry» filtration , hydrogen sulfide-containing underground water , anthracite filtering media , air oxygen

Sustainable biosolids management: a review of best available technologies for sludge stabilisation and volume reduction

Summary

Australian water utilities face a significant challenge in moving towards more sustainable biosolids management. There is increasing pressure to move away from the traditional approach of land application of dewatered biosolids due to escalating transport costs, community impacts such as odour and truck movements, and the risk of changing regulation or public perception affecting the future viability of land application. Different sludge treatments have been compared regarding performances, opex and carbon foot print for 2 case studies: Australian Inland and Coastal WWTP. Results have shown that thermal sludge treatments, especially Wet Air Oxidation which is now a proven technology, are highly competitive compared to conventional sludge treatments particularly when sludge disposal costs are high.

Key words

treatment facilities , sludge , thermal drying , incineration , liquid-phase oxidation , technosand , carbon emission