DE2044319A1 - Effluent treatment - by combined flotation/sedimentation and filtration - Google Patents

Abstract

Continuous purification of effluent or raw water, particularly 'white water' from papermaking, to give a product of fresh water quality, by the simultaneous use of pressure flotation an sand and/or gravel filtration in a single treatment vessel.

Description

Method and device for cleaning wastewater or

Raw water The invention relates to a method and a device for the purification of waste water or raw water and aims to be a continuously running one Cleaning in a small space to fresh water quality, which was previously only possible with great effort after using various coarse pre-cleaning methods with subsequent gravel and sand filtering could be achieved through chemical and biological processes.

Continuous cleaning is at least made more difficult, if not not possible.

fJas has runoff water from the well-known mechanical clarification systems still a relatively high proportion of solids, although generally for that Passing over this runoff water in the chemical or biological Sewage treatment plants, occasionally also permissible for flowing into canal or river beds is. This residual content is, for example, in the drainage water of the mechanical sewage treatment plants a paper mill between 20 - 100 mg / l. Such residual levels are too high to such drainage water as fresh water, e.g.

to be able to use them again in a paper mill or their fresh water requirements to be able to reduce.

For this purpose it is necessary that the clarifying effect is reliably brought to a residual content between 2 -10 mg / l.

The invention has set itself the task of such fresh water from the drainage water of mechanical sewage treatment plants in a simply structured and simple and in particular to generate continuously acting device and to this Chemical or biological cleaning or

To save clarification.

The purpose of the invention is achieved by simultaneously applying the Cleaning achieved by pressure allotation and gravel and / or sand filtering in a holder.

For this purpose, the wastewater mixed with air or

Raw water fed to a sewage treatment plant, the rising solids collected on the surface of the water and continuous or discontinuously discharged, while those following the descending water movement and thereby sinking solids are at the bottom of the sewage treatment plant and on one there deposit the provided sand or gravel layer and the pure water below the sand or gravel filter layer is removed.

For cleaning the sand or gravel filter of the sewage treatment plant is in further training of the method according to the invention, this filter layer by supplying from the The wash water from the septic tank is taken from the soil from the deposited solids cleaned by washing in countercurrent and so removed the dirt particles, whereby the filter layer is expediently divided into several chambers and these chambers cleaned one after the other.

With this combination of pressure flotation and sand or

Gravel filtration is achieved that about 80% of the waste water or raw water existing or suspended solids by flotation and thus as floating sludge be eliminated. The rest settles as sinking sludge at the bottom of the sewage treatment plant away. Part of this soil is covered with sand or

Provided gravel filter chambers, through which the flotation effect pre-cleaned wastewater passes through and thus finally purified to clear water to become. The surface of this filter layer is compared to the total floor area the sewage treatment plant is small, so that the proportion of the sinking sludge that is on the Surface of the filter layer settles compared to the I; Ienge which settles on the solid floor area is small. That means a quick one Clarifying effect, reduction of the deposits clogging or clogging the sand filter, a quick removal and strong thickening of the water level of the sewage treatment plant floating sludge collected and skimmed off there as well as for the sinking sludge on the floor and finally a self-cleaning of the sand filter by washing out. As this washing process progresses continuously all areas one after the other or chambers of the sand or gravel filter, the washing times interfere with the sand filter performance not, so that also thereby a continuous work with a high throughput rate or cleaning performance for the wastewater is achieved.

The wastewater or the raw water can, if necessary, with the known, added to the flocculation of the solids supporting flotation agents will.

With the application of the method according to the invention, the result is the following advantages.

The total amount of water drained from a workflow is reduced because a large part of this runoff water is caused by the intensive ISlarwirlcurl- of the method according to the invention is returned to the working cycle. Through this reduced The consumption of fresh water to be supplied from the outside naturally increases. This repatriation also reduces; heat losses everywhere in the work process Water heat must be supplied. There is the possibility of a perfect to create a closed water cycle, in which only the small amounts of loss must be replaced by evaporation with fresh water.

The possibility created by the method according to the invention on a biological further treatment of wastewater to achieve fresh water quality Being able to do without is of particular importance not only for economic reasons Reasons because for a certain workflow the water consumption is due to the amount of wastewater recovered from the cycle in the same quality is considerable can be reduced, but also for the water balance as a whole.

The invention further relates to a device for carrying out the above Procedure. This is based on a preferably cylindrical basin with Feed pipe for the waste water or raw water and with a central collecting funnel for the solids floating up in the triangle with a drainage line for them.

According to the invention, the feed pipe for the waste water and a Feed for clear water mixed with air into a centrally arranged in the corner Riser pipe that is in the upper Area appropriately distributed around the perimeter Has longitudinal slots with baffle and distributor webs in front. The bottom of the Basin has partly a slightly inwardly inclined settling surface with a above movable sinking sludge scraper and on the other part an annular channel with a gravel or sand filter layer provided therein. This annulus is by vertical Badial walls divided into a multitude of chambers. Next is the surface a chamber tightly closing height adjustable and optionally over each chamber Removable and removable cover plate with a longitudinal connector and connected to it Intake tube provided for backwashing. The backwash takes care of one on this one Pump connected to the suction pipe, between its outlet nozzle and the upper area there is a connection line of the riser pipe. To collect the clear water is below the perforated floor of the gravel or

Sand filter chambers arranged a clear water channel with a connection to the clear water storage room, which has a riser pipe with a height-adjustable overflow has in the clear water drain. There are also lines at the bottom of the container for discharge the floating sludge and the sinking sludge provided.

For setting and controlling the water level in the sewage system The overflow threshold provided in the upper area of the clear water collection chamber is appropriate of the clear water riser pipe set up to be adjustable in height.

Further preferred configurations of the device are features of the subclaims.

In the drawing is an embodiment of a device to carry out the method according to the invention shown in the scheme, on which further Details are explained. They show: Fig. 1 the sewage treatment plant in longitudinal section. 2 the top view of FIG. 1 The sewage treatment plant consists of the essentially cylindrical Basin 1 with the central riser pipe 2, the top bearing for the top of the pool revolving and rotating solids scraper 3, which is driven by the geared motor 4 receives its rotary motion over the surface of the pelvis and around its own axis. This solids scraper consists of at least one rotating around its axis, spiraling over the water level in the pool in a circular motion curved scoop. This spiral clearer is the subject of another application of the same applicant for wastewater treatment. This spiral clearer promotes in the Collecting funnel 5 for the floating sludge, which is discharged through line 6. The wastewater to be cleaned or raw water is through line 7 into the interior of the Riser brought.

Next is there in via line 8 and a subsequent one Ring line with arranged thereon, not shown Outlet nozzles Clear water mixed with air introduced from the basin. This clear water mixes with the sewage and after the pressure drop at the nozzles from the Free air bubbles emerging from water carry the solids upwards with them. the upward flow occurs via the in the upper area of the riser pipe 2 in uniform distribution on the circumference provided longitudinal slots 9 in the basin 1, wherein at a distance in front of pralifurfaces 10 for a largely uniform distribution of the air bubbles flowing up and laden with substance. While now the greatest Part of these solid particles float up to the water level of the pool, conveyed from the spiral scraper 3 to the collecting funnel 5 and discharged through the line 6 are followed by the rest of the particles, which are not captured by the air bubbles the water movement in the basin downwards.

The bottom of the pelvis consists of a slightly sloping inward extending part 11 with a collecting space 12 in connection with the riser pipe 2. About the floor 11 moves on ropes 13 or the like. Jialte organs hanging silt scraper 14 and conveys the sinking sludge that settles on the bottom to the collecting area 12. An this part of the floor is connected to the outside by the remaining area as an annulus, with a number of filter chambers standing next to one another with vertical walls 15 is filled. These filter chambers have a perforated bottom and are with a gravel and / or Layer of sand filled. Over the top margins 16 of these filter chambers 15 penetrates the water in the basin with settling of the itself the surface settling sinking sludge into the collecting channel 17 as clear water and from there it gets into the clear water collecting chamber 18, one of which is with the help of a geared motor 19 has a height-adjustable overflow 20 that depends on the water level of the system is controlled, e.g. via buttons and pulse generators. From this clear water collection room the clear water is removed at 21.

To these filter chambers 15 from the settling on the surface Free sinking sludge and thus a permanently effective filter effect in continuous To be able to guarantee the functioning is effective during normal operation washing device for the filter chambers 15 is provided. This consists in Embodiment in a cover plate 22, which from above onto a filter chamber is placed and seals the upper edge. This cover plate carries a Nozzle on which a movable suction line 23 with a built-in check valve 24 is connected, which leads to the backwash pump 25. This is on the one with the Spiral scraper 3 combined swing bridge 26 arranged, which on the upper edge of the pool performs a circular motion. At this swing bridge are the sludge clearers 14 supporting e.g. ropes 13 attached. Another one sits on this swing bridge Gear motor 27, which the Cover plate 22 via a cable gear 28 raises and lowers.

As soon as the cover plate 22 is lowered onto one of the filter chambers 15 is, the backwash pump 25 switches on and sucks out of the clear water collecting channel 17 clear water from bottom to top through the filter layer of this filter chamber.

This backwash water takes the settled sinking sludge with it above and emptied into a drain line 29 attached to the swing bridge the collecting funnel 5 at a distance encasing further collecting funnel 30, from where the entrained solids get back into the riser pipe 2 and thus again are fed to the wastewater to be cleaned, so again in the cleaning cycle come. In this way, all filter chambers are gradually cleaned.

The separated gravel or sand filters can be cleaned continuously and regenerate, so that the fresh water production is practically continuous. At the upper edge of the basin, an overflow (not shown) is arranged with whose help the water level in the pool is limited upwards.

Any flotation agent required can be installed in front of the intake port of the Pump not shown are added, with the help of which the wastewater on the Line 7 is conveyed into the riser 2. To be mixed with air for flotation To be able to give clear water into the basin is made possible by the pump 31 via a connection line 32 removed from the basin 1 clear water (about 15% of the total throughput) and the air sucked in from the atmosphere by a linear knife, which is not shown.

This air-laden clear water comes out of the pressure vessel 33 via the line 8 in the riser 2 of the basin 1, where it is with the through the Line 7 mixed sewage and - as described above - the floating the solids causes. The speed of this is directed upwards Current about four times faster than the speed at which the water flows through Sand or Gravel filter passed through.

The floating sludge that arises during cleaning is drained through the pipe 6 led into the collecting tank 34, in which further through the line 35 of the sinking sludge got. From there this sludge is preferably used with the help of a not shown automatic time-controlled pneumatic valve for any further use carried out. 36 is the body with the slip rings for all motors and pulse generators on the swing bridge or the spiral clearer patent claims ......

Claims (8)

Claims Process for the continuous purification of wastewater or raw water, especially up to fresh water quality, characterized by the simultaneous Applying cleaning by means of Bruckflotation and gravel and / or sand filtering in a container. 2. The method according to claim 1, characterized in that the with Air mixed wastewater or raw water is fed to a clarification tank, the ascending Solids collected on the water table surface and continuously or discontinuously are removed, the sinking solids are at the bottom of the clarifier and settle on a layer of sand or gravel provided there and the pure water underneath # this sand or gravel filter layer is removed. 3. The method according to claim 1 or 2, characterized in that the sand or kesfilterschicht in the hlsirbehälter by supplying from the container The wash water originates from each of the filter layers from the deposited solids is cleaned, the filter layer suitably divided into several kairjner and these chambers become LCrCiniu't one after the other. 4. Device for performing the method according to the claims 1 - 3, consisting of a preferably cylindrical basin with a supply pipe for the waste water or raw water and with a central collecting funnel for the solids with drain line for this, characterized in that the feed pipe (7) fit the wastewater and a feed (8) for clear water mixed with air into one Cylindrical riser pipe (2) which is arranged in the basin and which is useful in the upper area Longitudinal slots 9 evenly distributed around the circumference with baffle and distributor webs in front (10), the bottom of the basin has partially a slightly inwardly inclined settling surface (ii) with a sinking sludge scraper (14) that can be moved over it and, on the other hand, Weil one Annular channel with a gravel or gravel channel provided therein. Has sand filter layer, this Annular space divided into a plurality of chambers (15) by vertical radial walls is, a height-adjustable and tightly sealing the surface of a chamber Cover plate (22) that can be removed and removed again optionally over each chamber a suction nozzle and a suction pipe (23) connected to it are provided for backwashing is mli; a pump (25) connected to the suction pipe, one of its outlet nozzles with the upper area of the dough tube connecting line (29) zurn return les Filter washing water is provided in the container for C. #; To collect the clear water Below the perforated floor (gravel or sand filter chambers a clear water channel (17) is arranged with a connection to the Klarwassersammeiraum (18), which is a riser pipe with a height-adjustable overflow (20) in the clear water drain and further lines (6, 35) at the bottom of the container for discharging the floating sludge and the Sinking sludge are provided. 5. Apparatus according to claim 4, characterized in that in the upper Area Qs clear water collection room for setting and controlling the water level In the clear system, the height of the overflow threshold (20) of the clear water riser pipe is adjustable is set up. 6. Apparatus according to claim 4 or 5, characterized in that at the upper edge of the basin a continuous or discontinuous circulating Raker (3), expediently a spiral raker rotating at the same time is provided. 7. Apparatus according to claim 6, characterized in that the circulation end scraper (3) with the connecting line designed as a drainage channel (29) to the Recirculation of the filter washing water from the mistritts socket of the pump (25) into the upper area of the riser pipe combined to form a common circulating body (26) is, which is also the carrier for the gear motor (27) for moving the cover plate (22) for the filter chambers (15) and for the washing water pump (25) is. 8. Apparatus according to claim 6 and / or 7, characterized in that that preferably concentric to the center in the riser and at its upper edge arranged collecting funnel (5) for the floating sludge another collecting funnel (30) for taking up the filter washing water and returning it to the circuit is arranged.