ASP-system (Active Slam Process) använder elektricitet för att blåsa in luft i rått, osedimenterat avloppsvatten. Detta krossar de fasta ämnena för att utveckla en biologisk "soppa". Luftning gör det möjligt för de naturligt förekommande bakterierna i avfallet att smälta allt organiskt innehåll, vilket minskar den totala föroreningsnivån. ASP-reningsverk har ingen primär sedimenteringskammare, vilket innebär mindre frekvent tömning och färre oönskade lukter.
Once the sewage has been aerated for long enough, excess liquid is discharged into a clarification chamber, where live bacteria settle to the bottom. Dead bacteria rise to the top, leaving clean water in the middle – which can then be discharged safely into either a watercourse, drainage field or soakaway.
NEDSÄNKTA LUFTNINGSFILTER
In a submerged aeration filter, a primary settlement chamber holds solid material. This is where anaerobic digestion by bacteria takes place. Clarified water then passes into a second chamber containing a submerged media – and here, the water is treated to remove dissolved constituents by aerobic bacteria, supported by diffused air. This process ensures that full treatment is achieved before the material flows to a final settlement chamber. The final, treated wastewater is discharged to the drainage field, watercourse or soakaway.