Process Biochemisrry 29 ( 1994) 3 1 l-3 13

Patent Survey

This is a regular series of articles covering a selection of recent patents and patent applications from Europe, the USA and Japan.

Though many patent applications and patents on biotechnological processes have been published in Western Europe, USA and Japan during the last few months, the following are deemed to earn particular attention.

A new antifungal microorganism

(US patent 5,260,302, ZCZ, London, UK)

Maria Fattori and her co-researchers on biochemistry have found a new method for testing the inhibitory effect of a poten- tial antifungal agent in two tests, viz. a first test for inhibition of pathogen deve- lopment in sterilised soil infested with mycelium of Pythium spp. and a second test for inhibition of disease development in a growing plant, of a species suscept- ible to disease from damping-off disease complex in the presence of that complex. Agents which gave potential inhibitory effects in both tests were identified and compared wth a control. The method revealed four particularly useful micro- organisms which display antifungal activ- ity in a wide spectrum.

More specifically, the inventors pro- vide a method of protecting crop plants from fungal infection, in which a fungi- cidalIy effective dosage of one or more than one of the Pseudomonas jluores- tens strains, is applied to the plants, the roots or seeds, or the surrounding soil.

Strain NCZB 401187 was isolated from wheat roots in field Badbury 2, Draycott Farm, Chiseldon, Swindon, Wilt&ire, UK.

Strains NCZB 40186 and 40188 were isolated from soil taken from Stockoy Field in Jodoigne. in Belgium.

Strain NCIN 40190 was isolated from the roots of wheat seedlings from Lower Gastron field, Rushall Farm, Newbury, UK.

A method proposed for stabiliiing metals in wastewater sludge

(US patent 5,259,975, Betz Laboratories, Znc, Trevose, Pennsylvania, USA)

Michael Mohn, a biochemist of Levit- town, PA, USA, has discovered that tolyl- triazote has excellent metal complexing properties to inhbit leaching of metals from sludge solids into the environment. To the sludge he added up to 5000 ppm of tolyltriazote, to complex with and sta- biie the metal hydroxide precipitates in the sludge. As a result the propensity of the metal hydroxide precipitates to redis- solve and leach into a sludge disposal environment, under acidic leaching con- ditions found in the sludge disposal envi- ronment, was substantially reduced.

A new bilogical water and waste treatment apparatus

(USpatent 5,262,051, Japan Organ0 Co., Ltd, Tokyo, Japan)

Takeshi Iwatsuka, a biochemist of Sai- tama, Japan has developed an apparatus for biological treatment of water and waste of the attached-growth type, con- structed by disposing long fiber bundles, formed by binding a large number of fila- ments upward and downward in a zigzag formation in a vessel, substantially fixing the upper and lower angle portions, and incorporating supports for supporting the angle portions of the long fiber bundles into a part of a frame, assembled in ad- vance together with frame members. The apparatus is capable of high-volume treatment, causing little clogging, lower- ing construction costs, and is capable of stable long-term operation.

Figure 1 is a schematic cross section showing one of Iwatsuka’s designs.

(1) is a rectangular vessel in which many rod suppports (3) for hanging band- shaped long fiber bundles (2) are fixed in parallel in the upper section. Further, holding rods (4) are fixed horizontally in parallel for substantially affix@ the lower angle portions of the band-shaped

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6

=f 7

Fig. 1.

long fiber bundles (2) so that the bundles (2) do not float.

In this way, the long fiber bundles (2) are arranged in a zigzag formation from the standing wall on one side of the vessel to the other, and medium layers (5) are formed as a whole, composed of a num- ber of long fiber bundles (2) arranged relatively densely (small intervals are allowable) in the width direction.

(8) is a water distributor provided in the bottom section of the vessel and branched outside the vessle, one branch being connected to a raw water pipe (6) and the other to washing water pipe (7). The water distributor (8) has many holes to uniformly distribute water to be treated into the vessel. (10) is an air diffuser having a great number of pores, made of a cloth, such as fire hose, which is connected to air pipe (9) outside the vessel.

(12) is a trough provided on the top wall of the vessel, connected to delivery pipe (11) for discharging treated water outside.

Water to be treated is fed into the vessel through the holes of the water dis- tributor (8) by way of the raw water pipe (6). On the other hand, aeration air is fed via the air pipe (9) to the air diffusor (10) made of a hose cloth, from which are aerated minute air bubbles with a dia- meter of ca. 1 mm or less.

Thus, the water flows upwards into the vessel (1) in which the long fiber bundles (2) are arranged in a zigzag formation in

Process Biochemistv (29) (1994) -0 1994 Elsevier Science Limited, England.

312 Patent survey

bands,andorganicmatterinthewateris oxidized and decomposed biologically, to proceed pur&ation of the water by the activity of aerobic microorganisms grow- ing on the surface of each monofilament of the long fiber bundles (2).

The water pmified while flowing upwards in the vessel is passed to trough ( 12) and then discharged outside through the delivery pipe (11). The air aerated into the vessel (1) ascends as bubbles through the vessel and is directly dis- carded to the air.

Although suspended solids contained in the water are caught partiahy by the long fiber bundles (2) the majority rise through the bundles (2) and are dis- charged autside together with the treated water. The suspended solids are separ- ated from the treated water by solid- liquid separators such as a settling tank and a rotation tank.

TtleaerohicpurifieationsystempropoMd by de Vries

(Eutupean patent application 575 002 Co&emtive Verkoop- en ?Yodu&verhglng wn Aardappel-meel en Derivation AVEBE, Veenabn, The Netherlands)

Johanues de V&s, an engineer at bio- logical wastewater treatment plants in Drosten, The Netherlands, has deve- loped a system for the aerobic purifica- tion of wastewater. The waste is treated in an aeration chamber in which a substan- tially constant oxygen concentration is maintained by a calculating unit which receivesasignalindicativeoftheamount of oxygen instantaneously consumed per unit of time, and produces an output sig- nal indicative of the instantaneous pogu- tion burden.

Figure2isaflowdiagramofthede Vries system generally designated by (10) to purify waste from a production process shownby(l)andtwoproductionlines(2) and (2’) side by side and for each of these

production lines, two processing units (3), (4) and (3’), (4’), respectively.

Each of the process@ units (3), (3’), (4), (4’) produces waste, designated by (5), which is supplied to an aeration chamber (11). If required, the waste (5) may first be subjected to pretreatment at (6), such as screenin& filtering or settling.

Connected with the aeration chamber (11) is a supply line (12) for supplying oxygen from a reservoir, not shown, to the aeration chamber (11). Furthermore, the aeration chamber (11) is provided with an oxygen concentration detector (13) which is coupled with a controlling device (20). On the basis of the oxygen concentration in the aeration chamber (11) measured by the detector (13), the controlling device (20) controls the posi- tion of a control valve (14) arranged in the supply line ( 12) in such a nuumer that the oxygen concentration measured remains substantiahy equal to a predeter- mined target value.

The purified wastewater leaves the aeration chamber (11) via a line (15). Before it is discharged into the surface water, it may be subjected at (16) to post- treatment, e.g. settling, in which the sedi- ment formed may be returned to the aerationchamber(ll)viaahne(l7).

A calculating unit (30) is also provided coupled with the controlling device (20). Via signal path (3 1) the controlling device (20) provides the calculating unit (30) with a signal indicative of the amount of oxygen instantaneously consumed per unitoftime.Jncontrohingdevice(lO)this signal may be derived from the control signal for the control valve ( 14).

On the basis of the signal received from the controlling means (20), the cal- culating unit (30) provides at (32) an out- put signal indicating the instantaneous polhttion burden.

In a specialised design the calculating unit (30) and the controUing means (20) are designed as a combined controlling/ calculating unit. Thus the number of com-

(0 /

ponents is reduced and the connection (3l)canbeomitted.

The calculating unit (30) may be. cou- pled with detector (33) arranged in the supply line (5) for the aeration chamber (11)tomeasuretheflowrateofthewaste tobepurifkdIfdesired,thecakulating unit (30) may provide an output signal indicating the instantaneous polhnion burden per kilogram or litre of waste pro- duced.

(Ewopcon patenz applicutlon 575 052, Zlmpm Envbvnental, Inc., Rothschild, Wisconsin, USA)

John K. Berrigan and Timothy A. Deets have invented a biophysical treatment system in which an iron salt is added to an aeration basin of an aerobic biophysical treatment process which contains bioiogi- cal solids and powdered adsorbent. The iron removes metal comaminants by coprecipitation and the metal precipitate remains with the solids in the system The biological orgakns and powdered adsorbent remove carbonaceous pohu- tams, and the system effhrent has a low content of both carbonaceous and metal contaminants.

A continuous flow and a batch oper- ated system has been developed. Figure 3 is a flow diagram of the continuous

process. Wastewater contaminated with carbo-

naceous components and metal polhk tams, stored in a reservoir ( lo), enters the biophysical treatment system via conduit (12), which continuously delivers the wastewater to an aeration zone (14). The aeration zone (14) contains a mixture of wastewater, biological solids and pow- dered absorbent, preferably powdered activated carbon. The basin (14) is aer- ated and mired by an aeration means (16), such as sparge, supphed with air via conduit (18). The carbonaceous polht- tarns are removed from the wastewater by the metabolism of biological organ&s combined with adsorption by the pow- dered adsorbent, An optimal mechanical mixer (20) provides additional miring within the aeration rone (14).

The mixture of wastewater, biological solids and powdered adsorbent then flows via conduit (22) to a quiescent set- thug zone or clarifkr (24) where solids aresettkdfromtreatedliquid.Apolymer materialmaybeaddedtothemixtureasit entersthechwi6ertoassistinthesetthng of solids. The chuified liquid phase dii- charges from darBer (24) via conduit (26) while the settled solids phase, com- posed of biological solids and powdered

Patent survey

Fig. 3.

adsorbent, recycles via return conduit (28) back to the aeration zone (14) to maintain the desired concentration of biological solids and powdered adsorbent thereh~ Rxtions of the settled solids phase are sent to waste via waste conduit (30) to control solids concentration in the biophysical treatment system. Metal con- tammants are removed from the waste- water by adding a selected amount of

soluble iron salt to the aeration zone of the system. A solution of iron salt from reservoir (32) is added to the Muent wastewater in conduit (12) via conduit (34). ~te~tively the iron salt solution may be added directly to the aeration zone (14).

The iron salt may be either in the fer- rous (Fe*+) or the ferric (Fe3+) form, each with an appropriate counter ion, such as

chloride, sulfate, nitrate, bicazbonate.

carbonate or

copies of the t#?rerl&?Y cited can be

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obtained from the jXkwing oqwdzations, or ot the Patent O@ces of the respect&? COlUUkS.

European Potent Ojfce, Rijswijk, The ~et~~~ The Netherlands Patent Oji2e, Rijswij~ The Netherkmds; The Patent In~~n Deans of TNO, Rtjswijk, The Netherkmds; The International Patent Research @ice IPRO, PO Box f62&?, 250 BG. The Hague, The Netherkands; UK Patent C@ce, Concept House, Cardif Rood, Newport, Gust NIYIRH, UK; Vniwnto, PO Box 16056, The Hague? The Netherlands; USA Patent O@e, Box 4, Patent and Trademark O@ce, US Department of Commerce, Washington DC 20231, USA.