High-power ultrasound for sludge and biogas

The BIOSONATOR from ULTRAWAVES, a spin-off of Hamburg University of Technology founded in 2001, is a plug-and-play ultrasound unit. It makes organic matter easier to digest, in municipal sewage sludge as well as in agricultural, industrial and food-waste biogas plants.

Wastewater treatment Biogas plants

At a glance

2020 kHz, hard cavitationoscillators sit directly in the sludge→1–21–2 minutes per passonly a partial stream is treated→55 kW connected loadcontainer unit, installed in under a day→250+projects worldwideincluding a distillery in Ongole, India→

01 How it works

Hydrolysis is the bottleneck. Cavitation opens it.

Ultrasound at 20 kHz creates microscopic bubbles that implode with local pressures of around 500 bar. These shear forces crack cell walls and flocs, release enzymes and enlarge the surface the bacteria can attack. Because the oscillators sit directly in the medium, the cavitation is “hard”: according to ULTRAWAVES about ten times as effective as indirect sonication.

Macerator

Takes a partial stream, usually 30–50 % of the daily feed from the secondary digester, and cuts coarse fibres.

Pump

Eccentric screw pump with frequency converter sets the flow.

Ultrasound reactor

3–10 oscillators immersed in the medium, amplitude controlled automatically.

Flow meter and return

Treated material goes back to the digester; remote monitoring around the clock.

A Municipal and industrial wastewater

Wastewater treatment plants

For sewage treatment plants with anaerobic digesters and for aerobic sludge stabilisation. Particularly useful where digesters run at their load limit or sludge disposal is expensive.

+15–30 %digester gas

−50 %digestion time

up to −20 %excess sludge (aerobic)

+5–10 %dewaterability (relative)

Sludge disintegration
Bulking sludge and foam control
Internal carbon for denitrification
Less polymer for dewatering

Manufacturer figures, ULTRAWAVES GmbH.

Photo: wastewater plant with BIOSONATORfrom ULTRAWAVES (permission requested)

B Agriculture, food waste, co-digestion

Biogas plants

For plants from about 300 kW electrical or comparable BioCNG capacity, mesophilic or thermophilic, with up to 15 % dry matter.

+10–15 %biogas from the same feed

+1–4 %methane content

−5–13 %substrate cost

3–5 yearstypical payback

Fibrous substrates: grass, manure, straw
Lower viscosity, less stirring power
Fewer floating layers
Plug-and-play container

Manufacturer figures, ULTRAWAVES GmbH; payback depends on the site.

Ultrasonic cavitation diagram with BIOSONATOR compact

04 References

Selected ULTRAWAVES installations

Plant	Country	Type	Size	Since
Pearl Distillery, Ongole	India	Distillery	–	2012
Yanzhou WWTP	China	Wastewater	750,000 PE	2016
Shek Wu Hui WWTP	Hong Kong	Wastewater	350,000 PE	2014
Arrudas WWTP	Brazil	Wastewater	2,000,000 PE	2010
Dąbrowa Górnicza WWTP	Poland	Wastewater	200,000 PE	2008
Trier WWTP	Germany	Wastewater	170,000 PE	2015
Ense biogas plant	Germany	Biogas	2,500 kW	2015
Bordesholmerland	Germany	Biogas	1,600 kW	2011
Bispingen	Germany	Biogas	1,100 kW	2008

PE = population equivalent. Source: ULTRAWAVES reference lists.

05 Video

Ultrasound at the Ense biogas plant

A 2.5 MW plant in Germany that has run a BIOSONATOR since 2015. The video opens on YouTube; nothing is loaded from YouTube until you click.

Discuss a trial at your plant

Watch on YouTube