CN205603422U - Sewage treatment system suitable for samll cities and towns, rural area - Google Patents

Abstract

The utility model relates to a sewage treatment system suitable for samll cities and towns, rural area, including leading denitrification biological filter (1), aerobiont filter pond (2) and the dark bed filtering pond (3) of rearmounted denitrification that connect gradually, the delivery port of aerobiont filter pond (2) still connect the water inlet of leading denitrification biological filter (1) to the advanced treatment is carried out to partial directly flow in rearmounted denitrification dark filtering pond (3) of sewage that the feasible aerobiont filter pond's of follow (2) delivery port flows, and another part is returned leading denitrification biological filter (1) and is carried out preliminary denitrogenation processing. Compared with the prior art, the utility model has the advantages of sewage treatment is effectual, takes up an area of for a short time, manages simply relatively.

Description

A kind of sewage disposal system being applicable to samll cities and towns, rural area

Technical field

This utility model relates to a kind of sewage disposal system, especially relates to a kind of be applicable to samll cities and towns, rural area Sewage disposal system.

Background technology

Along with country's new countryside construction and the enforcement of urban-rural integration measure, the development speed of samll cities and towns of China Quickly.Firmly build portion minister, China Association of Mayors performs president in " Chinese Urban Development report 2012 " foreword Representing, at the end of 2012, China's urbanization rate has reached 52.57%, and the inhabitants live having more than half exists Cities and towns, this indicates that Chinese society form is changed into urban type by rural area type.At present, urban population there are about 50% Population be population in small towns.

" " 12 " whole nation urban wastewater treatment and the planning of regeneration Facilities Construction " proposes, to 2015 Year, wastewater treatment rate improves further, and treatment rate of domestic sewage reaches 85% (municipality directly under the Central Government, provincial capital and meter Draw city, single-row city to realize sewage and all collect and process, prefecture-level city 85%, county-level city 70%), at the sewage of county town Reason rate averagely reaches 70%, and organic town's wastewater treatment rate averagely reaches the construction object of 30%.

Visible, compared with the fast lifting of the wastewater treatment rate in city, the development that Small Town Wastewater processes is the most stagnant After, far below the wastewater treatment rate in city.Meanwhile, most samll cities and towns sewer does not become system, some profits With street and river channel draining, both affected environmental health, again river basins had been formed the pollution of area source of point source nature. It is therefore contemplated that, samll cities and towns of China drainage system will be with unconventional construction speed development, including drain pipe Canal system system and urban wastewater treatment firm, its amount of investment and quantities will be the most considerable.But, samll cities and towns' draining The construction of system can not indiscriminately imitate the construction experiences of the existing drainage system in big city, needs to explore as early as possible and meets state of China Feelings, efficient, energy-conservation, save land, advanced technology, economic and practical samll cities and towns' Drainage System Construction technology, commercial affairs and Management mode.

And the most conventional sewage treatmentmethod is: the structures such as AAO biological tank, batch-type biological tank take up an area big, Investment is big, and batch-type biological tank operational management specialization requires higher, is therefore not suitable for cities and towns, the least Cities and towns and the sewage disposal in rural area.

Utility model content

Defect that the purpose of this utility model is contemplated to overcome above-mentioned prior art to exist and provide one to be applicable to Samll cities and towns, the sewage disposal system in rural area.

The purpose of this utility model can be achieved through the following technical solutions:

A kind of sewage disposal system being applicable to samll cities and towns, rural area, including the Prepositive denitrification biological filter being sequentially connected with Pond, aerobic biofilter and rear-mounted denitrification deep-bed filter, before the outlet of described aerobic biofilter is also connected with Put the water inlet of denitrification bio-filter, and make the foul water fraction flowed out from the outlet of aerobic biofilter direct Flow into rear-mounted denitrification deep-bed filter and carry out advanced treating, before another part return Prepositive denitrification bio-filter is carried out Put denitrogenation processing.Use after first sewage tentatively being filtered by Prepositive denitrification bio-filter, due to now dirty The ammonia nitrogen etc. that in water, mainly denitrifying bacteria cannot reduce, it is therefore desirable to enter in aerobic biofilter by sewage After row oxidation of coal and biological nitration process, it is nitrate nitrogen etc. by mineralized nitrogen, is back to Prepositive denitrification more biological Filter tank is reduced into nitrogen by denitrifying bacteria, thus reaches the purpose of sewage water denitrification.Biological through Prepositive denitrification The sewage of the preliminary denitrogenation in filter tank is further continued for entering in rear-mounted denitrification deep-bed filter, carries out advanced nitrogen process.

Described Prepositive denitrification bio-filter is oxygen-starved biofilter, sets gradually the first water inlet cloth from top to bottom Gas-bearing formation, the first supporting layer and growth have first filter material layer of denitrifying bacteria, on the first described water inlet cloth gas-bearing formation also Connect the first water inlet pipe respectively, connect the first flush pipe of flushing out air and for the first blow-off pipe of spoil disposal, the The first outlet pipe connecting aerobic biofilter is also set up above one filter material layer.First filter material layer is preferably pottery gravel filtrate Layer.

Described aerobic biofilter sets gradually the second water inlet cloth gas-bearing formation, the second supporting layer and life from bottom to top Long the second filter material layer having aerobic microbiological, is additionally provided with the first water distribution gas distribution group in the second described water inlet cloth gas-bearing formation Part, this first water distribution cloth pneumatic module connect respectively be arranged on the second water inlet pipe bottom aerobic biofilter and second punching Wash pipe；

It is additionally provided with the second blow-off pipe for spoil disposal, above the second filter material layer bottom the second described water inlet cloth gas-bearing formation Also setting up the second outlet pipe connecting aerobic biofilter, this second outlet pipe connects Prepositive denitrification biological filter respectively Pond and the water inlet of rear-mounted denitrification deep-bed filter.Second filter material layer is preferably the mixing filtrate of cobblestone and volcanic rock Layer.

The sewage that the outlet pipe of aerobic biofilter flows out separately flows into Prepositive denitrification bio-filter and rearmounted anti-nitre The ratio changing deep-bed filter is 1-3:1.First water distribution cloth pneumatic module includes using canal formula matrix multiple spot water distribution and gas distribution Perforated pipe, water distribution gas distribution is carried out simultaneously, so by mixing wastewater with air technology, carries out the gas distribution water distribution of source, face, whole The gas distribution water distribution of face, pond is visibly homogeneous, non-blind area, without dead angle, gas distribution effect be much better than conventional single perforated pipe aerating regulation and Point source aeration head aeration, effectively prevent that the gas distribution water distribution of conventional filter tank is uneven, filter handle filter easily blocks, the easy plate of filtrate Tie, waterpower short circuit easily occurs, safeguard the problems such as complicated.

Described rear-mounted denitrification deep-bed filter includes filter tank main body, sets the most respectively at the top of filter tank main body and bottom There is the 3rd water inlet pipe and the 3rd outlet pipe connecting aerobic biofilter outlet, from upper in described filter tank main body It is sequentially provided with under to biomembranous 3rd filter material layer, and support the 3rd filter material layer being arranged at the bottom of the main body of filter tank The filter block layer in portion, is additionally provided with back purge system in filter block layer, is also equipped with carbon source and throws in dress on the 3rd water inlet pipe Put.3rd filter material layer is preferably quartz sand layer, and its particle diameter is 2-4mm.

Described filter block layer is formed by the tiling of polylith close-connected filter block, is formed porose between two adjacent filter blocks Gap；

Described filter block includes the brick body with packing groove, is also interval with multiple supporting leg two, brick body bottom, Wherein, the arch door shape passage placing back purge system, two supports that the same side is adjacent are formed between the supporting leg of both sides V-type passage is formed between lower limb.

Being also arranged above intake chamber in filter tank main body, the water inlet of this intake chamber connects the water outlet of aerobic biofilter Mouthful, the outlet of intake chamber connects the 3rd water inlet pipe, is also arranged above carbon source delivery device at intake chamber；

Described carbon source delivery device includes that the carbon source storage tank of built-in organic carbon source, nitrate nitrogen detector and PLC control System, carbon source storage tank is provided with control valve and the pipeline that feeds intake, described nitrate nitrogen detector is separately positioned on 3rd water inlet pipe and the 3rd water outlet pipe part, described control valve is all connected with PLC control system with nitrate nitrogen detector.

Described back purge system includes aeration tube and backwash water pipe, and described aeration tube connects outside by pipeline Aerator, described backwash water pipe by pipeline through backwashing pump connect backwash pond, in filter tank main body 3rd filter material layer is also arranged above sewage backwash pipe.

Time in the main body of sewage entrance filter tank, the 3rd water inlet pipe extend into below sewage level.

During work, sewage gravity enters Prepositive denitrification filter tank, and Prepositive denitrification filter tank is oxygen-starved biofilter, On first filter material layer, growth has denitrifying bacteria, and under anoxic conditions, denitrifying bacteria utilizes the organic carbon in sewage Source, is reduced into materials such as the nitrate nitrogen in the sewage of backflow from aerobic biofilter nitrogen and enters air, thus real Now preliminary denitrogenation processing.Then, the sewage gravity entrance aerobic biofilter after denitrogenation processing carries out oxidation of coal and nitre Change reaction, process the organic pollution in sewage and the harmful substance such as ammonia nitrogen and phosphorus, the dirt after aerobic treatment Water section is back to Prepositive denitrification filter tank, and another part is back to rear-mounted denitrification deep-bed filter and carries out advanced nitrogen Process, reach the total nitrogen purpose less than 3-5mg/L, improve wastewater treatment efficiency.

Compared with prior art, this utility model has the advantage that

(1) setting in pre-denitrification and denitrogenation filter tank, reasonably utilizes the Organic substance in former water as carbon source, saves Having removed additional carbon, reduced operating cost, the carbon source eliminating complexity adds control and drug storage system, keeps away simultaneously Exempt from tail water to produce CODcr because additional carbon is improper and exceed standard phenomenon.

(2) the second filter material layer in aerobic biofilter uses big particle diameter rough surface, robust cobblestone With honeycomb height hole, hydrophilic, durable volcanic rock mixed fillers, biological bed body is deep, and Biomass is big, then coordinates gas distribution The first water distribution cloth pneumatic module that water distribution is visibly homogeneous, bio-film colonization is uniform, activity is strong, and various microorganisms are survived by it Characteristic and substrate Parallel to the flow direction are distributed along journey, and organic matter removal efficiency is high, and water outlet ammonia nitrogen can reach below 1mg/l； Additionally, the mixing filtrate of the cobblestone of high porosity and volcanic rock does not retain into the solid suspension in water and biology solid Body, so for aerobic biofilter, as long as the most just washing and spoil disposal, simple to operate, the most thoroughly Eliminating conventional filter tank waterpower crossfire hidden danger, effectively prevent the generation of mud cake, mud ball, core solves submerged and exposes The common fault that gas biofilter is easily blocked up.

(3) rear-mounted denitrification deep-bed filter uses submerged water inlet (water inlet pipe is immersed under sewage level) thorough Avoid current high-order anti-weir in conventional articulated gravity filter tank to fall, cause the drawback of filter tank water inlet oxygenation, improve denitrification and take off Nitrogen effect saves carbon source dosage simultaneously；The rear-mounted denitrification deep-bed filter winter low temperature phase is run, and submerged is intake Can avoid falling, due to a conventional articulated gravity filter tank current high position, the water temperature caused to run off, keep preferable low temperature denitrification to imitate Really.

(4) owing to solids load is high, bed body is deep in rear-mounted denitrification deep-bed filter, homogenizing quartz sand composition 3rd filter material layer allows solid impurity through the top layer of filter bed, gos deep in filtrate, reaches whole filter tank depth and retains solid Body thing.

(5) backwash effect of rear-mounted denitrification deep-bed filter is good: owing to being the submerged water intake mode used, And the 3rd the hole of filter material layer the most relatively small with particle diameter, at this moment, the impurity such as float in the 3rd filter material layer will Constantly accumulation, the 3rd filter material layer can gradually lose effective head so that filter efficiency reduces, and now opens backwash Device, and close water inlet pipe, outlet pipe and carbon source delivery device etc..First opening aerator, aeration is to the 3rd filtrate Layer carries out gas rubbing and washes, and the biological membranous layer of float and inefficacy etc. is peeled off filtrate, opens backwashing pump the most again, Work together with aerator and carry out air-water backwash, the float etc. retained is gone out through sewage backwash bank of tubes.

(6) take up an area little, invest little: the effect of whole sewage disposal system is fine, and the volume in each filter tank is the most not Being very big, so that the volume of the whole system of composition is the most relatively small, investment reduces the most accordingly, particularly suitable In samll cities and towns, the sewage disposal in rural area.

Accompanying drawing explanation

Fig. 1 is the structural representation of sewage disposal system of the present utility model；

Fig. 2 is the main TV structure schematic diagram of the filter block of rear-mounted denitrification deep-bed filter of the present utility model；

Fig. 3 is the side-looking structural representation of the filter block of rear-mounted denitrification deep-bed filter of the present utility model；

In figure, 1-Prepositive denitrification bio-filter, 2-aerobic biofilter, 3-rear-mounted denitrification deep-bed filter, 11- First water inlet cloth gas-bearing formation, 12-the first supporting layer, 13-the first outlet pipe, 14-the first filter material layer, 15-first is intake Pipe, 16-the first blow-off pipe, 17-the first flush pipe, 21-second intakes cloth gas-bearing formation, 22-the second flush pipe, 23-the Two filter material layers, 24-the second outlet pipe, 25-the second water inlet pipe, 26-the second blow-off pipe, 31-carbon source delivery device, 32-intake chamber, 33-filter tank main body, 34-back purge system, 311-carbon source storage tank, 312-feeds intake pipeline, and 313-is controlled Valve processed, 314-nitrate nitrogen detector, 331-the 3rd water inlet pipe, 332-sewage backwash pipe, 333-filter block layer, 334- 3rd outlet pipe, 335-the 3rd filter material layer, 341-backwash water pipe, 342-aeration tube, 343-aerator, 3351- Brick body, 3352-supporting leg.

Detailed description of the invention

With specific embodiment, this utility model is described in detail below in conjunction with the accompanying drawings.

Embodiment 1

A kind of sewage disposal system being applicable to samll cities and towns, rural area, its structure is as it is shown in figure 1, include being sequentially connected with Prepositive denitrification bio-filter 1, aerobic biofilter 2 and rear-mounted denitrification deep-bed filter 3, aerobe is filtered The outlet in pond 2 is also connected with the water inlet of Prepositive denitrification bio-filter 1, and makes from aerobic biofilter 2 The foul water fraction that flows out of outlet flow directly into rear-mounted denitrification deep-bed filter 3 and carry out advanced treating, another part Returning Prepositive denitrification bio-filter 1 and carry out preposition denitrogenation processing, two-part flow-rate ratio is 1:2.

Prepositive denitrification bio-filter 1 is oxygen-starved biofilter, sees Fig. 1, sets gradually first from top to bottom Water inlet cloth gas-bearing formation the 11, first supporting layer 12 and growth have first filter material layer 14 of denitrifying bacteria, the first water inlet cloth It is also respectively connected with the first water inlet pipe 15 on gas-bearing formation 11, connects the first flush pipe 17 of flushing out air and for spoil disposal The first blow-off pipe 16, also set up above the first filter material layer 14 connect aerobic biofilter 2 the first outlet pipe 13, the first filter material layer 14 is preferably pottery gravel filter material layer.

Aerobic biofilter 2, sees Fig. 1, sets gradually the second water inlet cloth gas-bearing formation 21, second from bottom to top Supporting layer and growth have the second filter material layer 23 of aerobic microbiological, be additionally provided with first and join in the second water inlet cloth gas-bearing formation 21 Water cloth pneumatic module, this first water distribution cloth pneumatic module connects the second water inlet being arranged on bottom aerobic biofilter 2 respectively Pipe 25 and the second flush pipe 22；It is additionally provided with the second blow-off pipe 26 for spoil disposal bottom second water inlet cloth gas-bearing formation 21, The second outlet pipe 24 connecting aerobic biofilter 2, this second outlet pipe is also set up above the second filter material layer 23 24 water inlets connecting Prepositive denitrification bio-filter 1 and rear-mounted denitrification deep-bed filter 3 respectively (respectively the One water inlet pipe 15 and the 3rd water inlet pipe 331).Second filter material layer 23 is preferably the mixing filter of cobblestone and volcanic rock The bed of material.First water distribution cloth pneumatic module includes the pipeline using canal formula matrix multiple spot water distribution, and the perforation for gas distribution Pipe, water distribution gas distribution is carried out simultaneously.

Rear-mounted denitrification deep-bed filter 3, sees Fig. 1, including filter tank main body 33, at the top of filter tank main body 33 Further respectively have with bottom and connect the 3rd water inlet pipe 331 of aerobic biofilter 2 outlet and submerged water inlet 3rd outlet pipe 334, time in i.e. guarantee sewage enters filter tank main body 33, the 3rd water inlet pipe 331 extend into sewage Below liquid level, it is sequentially provided with from top to bottom in filter tank main body 33 with biomembranous 3rd filter material layer 335, and Support the 3rd filter material layer 335 is also arranged on the filter block layer 333 bottom filter tank main body 33, and the 3rd filter material layer 335 is excellent Electing quartz sand layer as, its particle diameter is 2-4mm.

Filter block layer 333 by polylith close-connected filter block tiling form, filter block structure as shown in Figures 2 and 3, phase The particle diameter hole less than quartz sand it is formed with between two adjacent filter blocks；Filter block includes the brick body 3351 with packing groove, Supporting leg 3352, wherein, shape between the supporting leg 3352 of both sides also it is interval with two, brick body 3351 bottom Become to place the arch door shape passage of back purge system 34, between two supporting legs 3352 that the same side is adjacent, form V-type Passage.

Being additionally provided with back purge system 34 in filter block layer 333, back purge system 34 includes aeration tube 342 and recoil Wash water pipe 341, aeration tube 342 is by the aerator 343 outside pipeline connection, and backwash water pipe 341 is by pipe Road connects backwash pond through backwashing pump, and the 3rd filter material layer 335 in filter tank main body 33 is also arranged above recoil Wash blow-off pipe 332.

3rd water inlet pipe 331 is also equipped with carbon source delivery device 31.Being also arranged above of filter tank main body 33 Intake chamber 32, the water inlet of this intake chamber 32 connects the second outlet pipe 24 of aerobic biofilter 2, intake chamber The outlet of 32 connects the 3rd water inlet pipe 331, is also arranged above carbon source delivery device 31 at intake chamber 32；Carbon source Delivery device 31 includes the carbon source storage tank 311 of built-in organic carbon source, nitrate nitrogen detector 314 and PLC control system, Carbon source storage tank 311 is provided with control valve 313 and the pipeline 312 that feeds intake, nitrate nitrogen detector 314 sets respectively Putting at the 3rd water inlet pipe 331 and the 3rd outlet pipe 334, control valve 313 and nitrate nitrogen detector 314 are all and PLC Control system connects.

During work, sewage gravity enters Prepositive denitrification filter tank, and Prepositive denitrification filter tank is oxygen-starved biofilter, On first filter material layer 14, growth has denitrifying bacteria, and under anoxic conditions, denitrifying bacteria utilizes having in sewage Machine carbon source, is reduced into nitrogen by materials such as the nitrate nitrogen in the sewage of backflow from aerobic biofilter 2 and enters air, Thus realize preliminary denitrogenation processing.Then, the sewage gravity entrance aerobic biofilter 2 after denitrogenation processing carries out carbon Oxidation and nitration reaction, process the organic pollution in sewage and the harmful substance such as ammonia nitrogen and phosphorus, at aerobic biochemical Foul water fraction after reason is back to Prepositive denitrification filter tank, and another part is back to rear-mounted denitrification deep-bed filter 3 Carry out advanced nitrogen process, reach the total nitrogen purpose less than 3-5mg/L, improve wastewater treatment efficiency.

Embodiment 2

Sewage except flowing out from the outlet of aerobic biofilter 2 flows directly into rear-mounted denitrification deep-bed filter 3 It is that outside 1:1, remaining is the most same as in Example 1 with the flow-rate ratio of entrance Prepositive denitrification bio-filter 1.

Embodiment 3

Sewage except flowing out from the outlet of aerobic biofilter 2 flows directly into rear-mounted denitrification deep-bed filter 3 It is that outside 1:3, remaining is the most same as in Example 1 with the flow-rate ratio of entrance Prepositive denitrification bio-filter 1.

The above-mentioned description to embodiment is to be understood that for ease of those skilled in the art and use reality With novel.These embodiments obviously easily can be made various amendment, and handle by person skilled in the art General Principle described herein is applied in other embodiments without through performing creative labour.Therefore, this practicality The novel above-described embodiment that is not limited to, those skilled in the art are according to announcement of the present utility model, new without departing from this practicality Improvement and amendment that type category is made all should be within protection domains of the present utility model.

Claims (10)

1. the sewage disposal system being applicable to samll cities and towns, rural area, it is characterised in that include being sequentially connected with Prepositive denitrification bio-filter (1), aerobic biofilter (2) and rear-mounted denitrification deep-bed filter (3), described The outlet of aerobic biofilter (2) be also connected with the water inlet of Prepositive denitrification bio-filter (1), and make The foul water fraction flowed out from the outlet of aerobic biofilter (2) flows directly into rear-mounted denitrification deep-bed filter (3) Carrying out advanced treating, another part returns Prepositive denitrification bio-filter (1) and carries out preliminary denitrogenation processing.

A kind of sewage disposal system being applicable to samll cities and towns, rural area the most according to claim 1, its feature Being, described Prepositive denitrification bio-filter (1) is oxygen-starved biofilter, sets gradually from top to bottom One water inlet cloth gas-bearing formation (11), the first supporting layer (12) and growth have first filter material layer (14) of denitrifying bacteria, It is also respectively connected with the first water inlet pipe (15) for sewage charging in the first described water inlet cloth gas-bearing formation (11), connects Lead to first flush pipe (17) of flushing out air and be used for first blow-off pipe (16) of spoil disposal, in the first filter material layer (14) Top also sets up the first outlet pipe (13) connecting aerobic biofilter (2).

A kind of sewage disposal system being applicable to samll cities and towns, rural area the most according to claim 1, its feature Be, described aerobic biofilter (2) set gradually from bottom to top the second water inlet cloth gas-bearing formation (21), Two supporting layers and growth have second filter material layer (23) of aerobic microbiological, the second described water inlet cloth gas-bearing formation (21) Inside being additionally provided with the first water distribution cloth pneumatic module for water distribution gas distribution, this first water distribution cloth pneumatic module connects respectively and is arranged on Second water inlet pipe (25) of aerobic biofilter (2) bottom and the second flush pipe (22) connecting flushing out air；

Described second water inlet cloth gas-bearing formation (21) bottom is also connected with the second blow-off pipe (26) for spoil disposal, the Two filter material layers (23) top also sets up the second outlet pipe (24) connecting aerobic biofilter (2), and this second goes out Water pipe (24) connects Prepositive denitrification bio-filter (1) and the water inlet of rear-mounted denitrification deep-bed filter (3) respectively Pipe.

A kind of sewage disposal system being applicable to samll cities and towns, rural area the most according to claim 1, its feature Being, the sewage that the outlet of aerobic biofilter (2) flows out separately flows into Prepositive denitrification bio-filter (1) It is 1-3:1 with the ratio of rear-mounted denitrification deep-bed filter (3).

A kind of sewage disposal system being applicable to samll cities and towns, rural area the most according to claim 1, its feature Being, described rear-mounted denitrification deep-bed filter (3) includes filter tank main body (33), in filter tank main body (33) Top and bottom further respectively have the 3rd water inlet pipe (331) and the connecting aerobic biofilter (2) outlet Three outlet pipes (334), are sequentially provided with from top to bottom with biomembranous 3rd filter in described filter tank main body (33) The bed of material (335), and support the 3rd filter material layer (335) and be arranged on filter tank main body (33) bottom filter block layer (333), in filter block layer (333), back purge system (34) it is additionally provided with, upper also at the 3rd water inlet pipe (331) Carbon source delivery device (31) is installed.

A kind of sewage disposal system being applicable to samll cities and towns, rural area the most according to claim 5, its feature Being, described filter block layer (333) is formed, between two adjacent filter blocks by the tiling of polylith close-connected filter block It is formed with hole；

Described filter block includes the brick body (3351) with packing groove, is also spaced two, brick body (3351) bottom It is provided with multiple supporting leg (3352), wherein, is formed between the supporting leg (3352) of both sides and place back purge system (34) arch door shape passage, forms V-type passage between two supporting legs (3352) that the same side is adjacent.

A kind of sewage disposal system being applicable to samll cities and towns, rural area the most according to claim 6, its feature Being, be also arranged above intake chamber (32) in filter tank main body (33), the water inlet of this intake chamber (32) is even Connecing the outlet of aerobic biofilter (2), the outlet of intake chamber (32) connects the 3rd water inlet pipe (331), It is also arranged above carbon source delivery device (31) at intake chamber (32).

A kind of sewage disposal system being applicable to samll cities and towns, rural area the most according to claim 7, its feature Being, described carbon source delivery device (31) includes that the carbon source storage tank (311) of built-in organic carbon source, nitrate nitrogen detect Instrument (314) and PLC control system, carbon source storage tank (311) is provided with control valve (313) and throwing Pipe material (312), described nitrate nitrogen detector (314) is separately positioned on the 3rd water inlet pipe (331) and the 3rd and goes out Water pipe (334) place, described control valve (313) and nitrate nitrogen detector (314) are all with PLC control system even Connect.

A kind of sewage disposal system being applicable to samll cities and towns, rural area the most according to claim 5, its feature Being, described back purge system (34) includes aeration tube (342) and backwash water pipe (341), described Aeration tube (342) is by the aerator (343) outside pipeline connection, and described backwash water pipe (341) passes through Pipeline connects backwash pond through backwashing pump, in the 3rd filter material layer (335) top of filter tank main body (33) also It is provided with sewage backwash pipe (332).

A kind of sewage disposal system being applicable to samll cities and towns, rural area the most according to claim 5, its feature Being, when sewage entrance filter tank main body (33) is interior, the 3rd water inlet pipe (331) extend into below sewage level.