Process Biochemistry 26 (1991) 249

Patent Survey

This is a regular series of articles compiled developed by H. Chmiel et al by Marten Terpstra and Sebastiaan (Fraunhofer-Gesellschaft Zur Fijrderung Gieskes covering a selection of recent der Angewandte Forschung E.V., patents from Europe, USA and Japan. Miinchen, FRG).

The process comprises the extraction of the contaminants, with a volatile, lipophilic agent having a lower density than water, from a watery suspension of contaminated soil particles. After separation of the extracting agent from the suspension, the agent is retrieved through distillation and recycled. The remaining contaminants are fed into another reactor for biological degradation.

Process for the prevention and control of biological fouling in aqueous systems

(European patent application 422948) A process for inhibiting the adhesion of bacterial cells to solid surfaces in aqueous systems and thus controlling biological fouling has been developed by C. G. Holls et al (Buckman Laboratories International Inc, Memphis, Tennessee, USA).

Conventional substances for control of biological fouling in aqueous processes are toxic and damage materials. The new process comprises the inhibition of the adhesion of this biofilm by the addition of 0.5 to 5 ppm of cationic, ionene polymers.

Process for the removal and destruction of biodegradable contaminated soils

(European patent application 432651) A process for the removal and destruction of biodegradable contami- nants from contaminated soils has been

The method is also applicable for the treatment of waste water from deposits or soil treatment processes.

Process for the aerobic nitrification of effluents

(European patent application 433139) A process for the aerobic nitrification of effluents has been developed by G. Martin (Atochem, Puteaux, France). The novel method uses a granulate support which is consumed during the nitrification. The support should comprise solid carbonates such as CaCO, or MgCO,.

After its entry into the reactor, the

Table 1.

support is activated by the biomass. Activation can be promoted by the addition of liquid nutrients for bacterial growth. The process is especially suited for NH,+ concentrations in the range 15-500 mg/l. The reactor should be stirred or consist of a fluidised bed. Mixing can be partially achieved by recirculation of a fraction of its effluent. Its operating temperatures should be between 5 and 30 “C, and in general the pH should be in the range from 7 to 9.

Some test results with the new process are given in Table 1.

Copies of the references cited can be obtained from the following organizations:

European Patent Ojice, Rijswijk, The Netherlands; The Netherlands Patent O&e, Rijswijk, The Netherlands ; The Patent Information Department of TNO, Rijswijk, The Netherlands; The International Patent Research Ofice IPRO, PO Box 16260, 2500 BG, The Hague, The Netherlands; Univentio, PO Box 16056, The Hague, The Netherlands; or at the Patent Ojices of the respective countries.

uo Q RQ Bi W-NH,+)0 NNH,+), NW,+), NW-), JVNO,‘-)~ Remarks

8.4 6.8 5.4 4

4

1.9-2.2

0.1 0.2 0.3 0.4

42 34 21 20

19-22

22.5 28 32.5 36

353-36.0

21.5

100 109 105 100

465 490 500 485

23

62 57.2 44.5 28.5

244 2.56

11.40 122

60 18 64.5 5 40.2 1 28.5 < 0.1

< 0.1 40 0.1 210 4.8 340

115 270

0 0

238 40 58

380 230 110 60

23

Bi= 10 -0.66 uo

qdUo < 4m/h

1.0-1.2 48-50 51 71 93

254

:: 35+15 12 20-40 35

200 30 20

2.5 17.5 25 3.53 0 < 0.1 21 5 15 6.28 0.25 5 15

4 6 14 35.5-36.0 9.75 3.4 8.1 IO.5 8 12 15.25 8.7 13.5 I

10 10 18.60 12.2 IO < 0.5

Uo = velocity of recycling (m/h); Q = feeding velocity (l/h); RQ = rate of recycling (I/h); Bi = biomass quantity at the centre of the reactor (g/l]; (N- NH,+), = nitrogen concentration at the reactor entrance (mg/l); N-(NH&‘), = nitrogen concentration in the middle of the reactor (mg/l); N-(NH, ), nitrogen concentrations of the effluent (mg/l)).

249

Process Biochemistry (26)--O 1991 Elsevier Science Publishers Ltd, England.