The EU has set high standards for reducing levels of nitrogen and phosphorus in domestic and industrial wastewater. An effective way of meeting these standards is the alternate application of aerobic and anaerobic biological treatment.
Put simply, fine bubble aeration promotes the conversion of nitrogenous material to nitrate, and the anaerobic cycle converts the nitrate to harmless nitrogen. During this process phosphorus compounds are precipitated out. A final aeration delivers a dissolved oxygen content of over 2 mg/litre to the purified water before discharge to watercourses.
The ‘Elastomer’ diffuser consists of a rubber diaphragm fitted over a polypropylene base plate featuring a central male ¾” taper BSP air entry port. The diaphragm is pierced with 4,500 small slits and clamped in place with a stainless steel clip. Each diffuser unit is connected to a pumped air supply and delivers up to 5m3/hour in the form of 2mm diameter bubbles.
The unique slit geometry gives an even pattern of bubbles yielding a Standard Oxygen Transfer Efficiency of over 6% and energy efficiencies of 4.5 kgmO2/kWhr in clean water. There is no back leakage on shut down and the slits are self cleaning.
‘Elastomer’ diffusers can be fitted with four types of rubber diaphragm.
- EPDM is suitable for domestic wastewater treatment plants.
- Hydrogenated nitrile is ideal for industrial wastewater heavily contaminated with oil.
- Viton recommended for harsh chemical exposure.
- Silicone rubber is ideal for hard water and leachate applications where there is a risk of lime scale which does not stick to silicone rubber.
All these compounds are immune to biological attack and we have had no reported failures since the product was launched in 1999.