LSP™ (Low Sludge Production)

An ecological solution to reduce sludge production

In a conventional aerobic biological treatment process, sludge production may be as high as 0.3 kg per kg COD removed. The AnoxKaldnes LSP™ process may decrease the sludge production by 30-90%, or down to 0.02-0.15 kg per kg COD removed.

The LSP™ technology is based on a two-stage process where in the first stage mainly free-living bacteria are promoted to grow. These dispersed bacteria will remove most of the biodegradable COD in the wastewater. The second activated sludge stage favors the growth of floc forming bacteria and large quantities of protozoa. The floc forming bacteria consume the remaining degradable COD and the protozoa feed on the free-living bacteria coming from the first stage. The outcome is a prolonged food chain and, consequently, a lower overall amount of waste sludge produced.

Range of applications

The LSP™ process is being applied with great success in the treatment of pulp mill wastewater. The sludge production has been decreased significantly while still retaining high and reliable treatment efficiency. The LSP™ technology has application for other kinds of wastewater.  The process configuration and ecological balance is tailored by AnoxKaldnes to suit each individual case.

A release of nutrients (nitrogen and phosphorus) in the second activated sludge stage is a natural outcome in the LSP™ process. If the demands regarding release of nutrients are stringent then a better alternative to reduce the sludge production may well be a nutrient limited BAS™ process.