Updated: July 2002

1. Introduction

The sponge activated sludge method is developed by KYOTO Prefectural Consulting Center for Medium and Small Enterprises, and equipped with more capacity.
The sponge is used as a support carrier and adheres coagulating microorganisms and acts as an activated sludge in the pores and sustains them there, and purify wastewater.
Sponge activated sludge method means macro-particles of activated sludge originally muddy and maintained on a special sponge and have many good performance.
Comparing with conventional methods, simple treating, compact and inexpensive.

2. Characteristics

More change of microorganismatic phases were observed in the sponge activated sludge than in flowing activated sludge, because microorganisms composing sludge were fixed inside the sponge. The surface layer appeared to be aerobic, for zoogloea, protozoa and sphaerotilus were observed, but internally parts of the sponge seem to be anaerobic because the sludge was blackish.
1) The high concentration of sludge is retained.
The high resistance to the load changes, and the digestion of sludge is little.
2) Anaerobic treatment to a sponge interior and aerobic treatment on the outside of the sponge are carried out, simultaneously.
The possibility of nitrification and denitrification in the same tank can be considered.
3) In the microorganismic phase on the surface layer mold fungi such as sphaerotilus are predominant and coexist with zoogloea.
Sphaerotilus is rejected as cause of bulking in an activated sludge process, but in a sponge activated process normal treatment is carried out at the present with sphaerotilus.
4) Large-sized microorganisms live in the sponge.
Large-sized microorganisms of low growth rate such as metazoa and annelid can live easily in the sponge, so growth of sludge is low, because of not only self-digestion but food-chain.

3. Performance

1) Simple treating system
Activated sludge is fixed in the sponge and filament-bacteria such as mold fungi sphaerotilus is available so activated sludge is controlled easily
2) Few excess sludge (1/10 of conventional method)
High rate of sludge self-digestion (by high concentration of sludge)
Food-chain (by large-sized microorganisms)
3) Compact (occupied area of equipment 1/3 of conventional method)
Because of highly-dense activated sludge of sponge
4) High resistance to the shock load
By macroparticles of activated sludge high resistance to shock and change load.
Treatment capability barely decreased after long time

4. Equipment

On outside of not tube sponge made by durable plastic is fixed, arrange adequately in the aeration tank. The aeration tank consist of aeration zone and sponge fixed zone. Wastewater circulate through aeration zone and sponge fixed zone by aeration and is purified.

5. Figure (Flowchart)

6. Subject

Food manufacturing industry
Marine product: frozen food
Agricultural products: canned food, pickled vegetables, ham, brewery, tofu, noodle
Other food product: soup, juice, provision of lunch fermented coloring matter, confectionery
Textile industry: silk, bleaching, dyeing

7. Example

Noodle factory
Wastewater treatment equipment: 350m³/d