The vegetative cover treatment method of long buring age buring field percolate
Technical field
The present invention relates to a kind of consumer waste landfill percolate treatment process, specifically be to comprise long fill out age percolate or the weak point that has close water quality characteristic with it fill out the age percolate through the treatment technology of biological treatment water outlet.Belong to solid waste treatment and disposal technical field.
Background technology
The main secondary pollution of consumer waste filling and embedding disposal process is a landfill percolate, landfill percolate has the high and changeable characteristic of water quality of pollution load, see (' Present and Long-Term Composition of MSWlandfill leachate:A Review. ' Kjeldsen P, Barlaz M A, Rooker A P, et al.Critical Reviews inEnvironmental Science and Technology 32 (4): 297-336,2002), there is very big threat in the environment to the landfill yard periphery.Although the processing of landfill percolate has been subjected to the attention of height, and developed type landfill percolate treatment process widely, but still there is comparatively serious defective in actual applications in these technology: perhaps cheap the but treatment effect of processing cost, particularly difference is filled out the percolate bad adaptability in age, perhaps treatment effect is good but processing cost is high.Be embodied in: 1) biology that processing cost is lower (comprising aerobic and anaerobism) is although treatment process (COD, BOD more effectively
5Clearance>80%) handle the landfill operating period and lack the landfill percolate (also claiming to lack to fill out the percolate in age) of (less than 5 years), but grown the percolate (also claiming the long percolate in age of filling out) of the landfill yard of (greater than 5 years) the landfill operating period, but almost there is not treatment effect, see (' Review:Anaerobic treatment of municipal sanitary landfill leachates:the problem of refractory andtoxic components ' Alkalay D, Guerrero L, Lema J M et al.World Journal of Microbiologyand Biotechnology 14 (3): 309-310,1998); Moreover, even at present the most perfect biological treatment is shortly filled out age during percolate handling, the COD of its treat effluent is general all about 1000mg/L, is difficult to reach the relevant emission standards of country, still has bigger threat to entering water body.2) there is the problem of technology and cost two aspects in materilization freatment method.Materialization handle generally with the length that is difficult to carry out a biological disposal upon fill out age percolate and the short age percolate filled out be object through the water outlet of biological treatment, in actual applications, only there are two class technological methods to have the water outlet of making possibility up to standard, be nanofiltration or the reverse osmosis in advanced oxidization method and the membrane technique, but this just is two kinds of expensive materilization freatment methods, there is tangible economic obstacle (' Advanced physico-chemical treatmentexperiences on young municipal landfill leachates ' Ozturk I in the application, Altinbas M, Koyuncu I, et al.Waste Management, 23:441-446,2003); Simultaneously, also there is certain environmental risk in physical chemistry method.The complicacy of chemical oxidation of gold approach makes might there be highly toxic micropollutant in the treat effluent that the mechanism of membrane method is to hold back, and still there is once more the problem of treatment and disposal in the concentrated attitude pollutent that is retained down.
Therefore, long fill out age percolate or the weak point that has close water quality characteristic with it fill out the age percolate through the treatment technology of biological treatment water outlet, be still the main challenge in the household refuse landfill sites secondary pollution control.
Summary of the invention
The object of the present invention is to provide that a kind of to satisfy processing cost simultaneously low and treatment effect is good, and be applicable to long fill out age percolate or the weak point that has close water quality characteristic with it fill out the treatment process of percolate biology treat effluent in age.
To achieve the object of the present invention, at first the long and short water quality characteristic of filling out the percolate in age is analyzed, the compositional analysis of taking from two kinds of percolate water samples of Shanghai City Lao Gang household refuse landfill sites the results are shown in Table 1; Wherein, water sample A: for the landfill time has surpassed the percolate of the landfill unit in 3 years, water sample B: for the landfill time less than the water outlet of 1 year percolate through anaerobism, aerobic 2 grades of biological treatments.
Table 1 is long fills out percolate and the composition of percolate biology treat effluent in age
In the table 1) be total dissolved organic carbon, 2) be hydrophilic component, 3) be fulvic acid, 4) be humic acid.
By table 1 as seen, with regard to the main magnanimity pollutent of two classes of percolate: with regard to oxygen consumption organic matter (characterizing) and the ammonia nitrogen with COD or DOC, grow fill out age percolate and the water quality of percolate biology treat effluent similar substantially; The dissolved organic matter molecular weight distribution in these two kinds of sewage of while and the feature of wetting ability classification (hydrophilic component, humic acid and fulvic acid) be basically identical also.According to water quality characteristic, can find that the reason that this type of sewage is difficult to carry out a biological disposal upon is:
(1) organism (DOC) is mainly formed by macromolecular substance and for the material of humic acids, is difficult to be utilized by Institute of Micro-biology in the limited time;
(2) ammonia nitrogen and BOD
5Ratio be about 10, the denitrifying carbon source deficiency can not be finished biological denitrification process.
Foundation of the present invention is that vegetation-soil ecology is to irrigating the conversion capability of pollutent in the sewage.Vegetation soil ecology finds have to shifting to new management mechanisms of pollutent: plant is to the absorption of nutrition (ammonia nitrogen), root system of plant and soil microorganisms are nitrated to organic degraded and ammonia nitrogen, microorganism to the denitrification of ammonia nitrogen and soil particle to absorption of soil ulmin (macromole hydrophobic nature organism) etc.As seen, vegetation soil ecology have purify long fill out age percolate and with it the similar weak point of water quality fill out the age percolate through the suitability of the water outlet of carrying out a biological disposal upon, be specially: 1, the ammonia nitrogen in the percolate can be utilized by plant absorbing, or by microorganism nitrated for nitric nitrogen, utilize the organism denitrification in the soil to be N subsequently
22, adsorbable in soil based on the larger molecular organics of soil ulmin, and become the part (quality of improving the soil) of soil; 3, the organism of intermediate molecular weight is also adsorbable in soil, and utilizes the long residence time that forms thus to be Institute of Micro-biology's degraded step by step.
Therefore, the soil treatment long buring age buring field percolate that utilizes vegetation to cover has the pertinency on the mechanism, be basic fundamental foundation of the present invention, the concrete technical problem that the present invention based on this will solve is the load control problem and the implementation method of this treating processes.Obviously, utilizing vegetation-soil ecosystem to handle long basic demand of filling out the percolate in age is that vegetation must survive and have certain biomass increment, exceed certain limit and will inevitably cause plant and comprise and cause the disadvantageous effect of withering and bring pollutent in the soil into by percolate, therefore, need control the pollution load of the vegetation-soil treatment of percolate; Simultaneously, handle the water yield and load when excessive, moisture can block the transmission of oxygen in interstices of soil in the air, makes plant impaired because of the root system anoxic, therefore, also needs to control the water yield load of processing.The present invention serves as according to having proposed relevant control data (specifically seeing technical scheme) with laboratory and site test results.The enforcement that utilizes vegetation-soil treatment percolate is to realize by the irrigation of percolate at the vegetation soil layer, secondary pollution for control irrigation process, the present invention has adopted the method for the irrigation ditch seepage flow of soil property covering, soil is irrigated, make percolate neither directly be exposed in the air in the irrigation process, the soil surface of also not flowing through, the foul smell that has cut off percolate in the irrigation process thus effectively distributes the approach with runoff pollution, has realized the effective control to the treating processes secondary pollution.
Concrete scheme is as follows:
Earlier by irrigating load control requirement, be built with pedosphere that vegetation covers, be vegetation-pedosphere and irrigation water carrying services; Then with BOD
5The quality volumetric concentration is less than the percolate of 200mg/L, by irrigating water carrying services, every day 2 times or 1 time, irrigates according to following method: during temperature on average 〉=15 ℃, and 15L/m
2D; During 4~15 ℃ of temperature on average, 8L/m
2D; During temperature on average<4 ℃ or when daily rainfall during, stop to irrigate greater than 15mm; During daily rainfall 8-15mm, vegetation-pedosphere is irrigated by the amount of above-mentioned water yield load 1/2.Percolate by the microbial metabolism effect in root system of plant and the pedosphere, makes the pollutant purification of percolate after irrigating, and the clearance of COD, ammonia nitrogen, total nitrogen can reach about 90%, 95% and 80% respectively; Utilize evaporation, the transpiration of vegetation and soil surface simultaneously, make the percolate decrement: the length of irrigating every square metre of vegetation-pedosphere, every day is filled out age or is shortly filled out age (water outlet after the carrying out a biological disposal upon) COD of percolate and the upper limit of ammonia nitrogen loading is respectively 24g and 18g.
The edaphic construction process that vegetation of the present invention covers is in two kinds of situation:
When constructing the position and be the final coverage rate of landfill yard, be to arrive at landfill to specify on the final waste layer that covers elevation, arrange respectively from bottom to top: rubble adjustment layer, clay close layer, fill stratum, above the agric of vegetation is arranged, wherein the laying depth of fill stratum and agric all is not less than 0.3m.
When constructing the position outside landfill yard the time, at first smooth (gradient is 2% to 20%) carried out on ground outside the venue; Then, lay the sand water conservancy diversion layer 0.2m of particle diameter<1cm thereon earlier, interval 10m lays a perforated pipe (concrete or HDPE tubing) in this layer, to draw groundwater flow; Cover clay 0.2m, also smooth on the sand water conservancy diversion layer again; Re-lay HDPE film (the two-sided subsides 200g/m of thickness 1mm on the clay
2The geotextile protection), establishes the earthwork grid of 0.5cm on the HDPE film and do layer of displacement, derive and irrigate water seepage.The lowest part of grid layer of displacement is established french drain and is collected water seepage, and confluxes to the water seepage storage pond; The water seepage storage pond adopts the mode of digging pit to make up, the antiseepage of liner 1mmHDPE film, the volume in pond should be 1.5 times of maximum day percolate treatment capacity of vegetation-soil facility, establishes outer comb (band valve) of water seepage and water seepage reflux pump (being connected to an interior percolate storage pond) in the pond; Fill stratum 0.5m is arranged on the earthwork grid, cover agric 0.3m on it again.
The method for arranging of irrigation water distribution of the present invention and water carrying services is, irrigation ditch at first is set on agric irrigates the usefulness of water distribution as percolate, irrigation ditch is the Tu Gou of the about 0.2m of the degree of depth, width 0.2~0.4m, about 80% of its degree of depth is filled the graded broken stone of particle diameter 20~40mm, cover clay on the rubble, directly contact and prevent the inflow of surface water runoff with atmospheric with isolated percolate; Irrigation ditch arranges that according to the level line on pedosphere surface the spacing between the irrigation ditch is 5~10m, gets suitable value according to agric surface gradient size in this scope.Irrigation ditch inlet is connected with input channel, makes percolate energy every day inject irrigation ditch off and on 1~2 time, infiltrates constantly among the soil by flow event again, finishes irrigation.Through monitoring up to standard effluxing, the storage pond that returns not up to standard circulates by the water seepage at the bottom of the vegetation soil seepage flow arrival waste layer.
Vegetation of the present invention covers method for arranging, and vegetation is that herbage and fast-growing tree mix vegetation, and each is a kind of should to comprise herbage and fast-growing tree at least, quick growing species of trees space between plants 2~4m, and herbage is full seeding on whole soil face then.
Outstanding effect of the present invention is:
1. because after percolate of the present invention poured into the pedosphere that specific vegetation covers, the microbial metabolism effect by in root system of plant and the pedosphere made BOD
5The clearance of the COD after the quality volumetric concentration is handled less than the percolate of 200mg/L, ammonia nitrogen, total nitrogen can reach about level of 90%, 95% and 80% respectively.
2. the present invention also has the effect of water yield decrement, in average temperature of the whole year 〉=15 ℃ and annual rainfall be not more than the area of water surface evaporation, but the decrement water yield 〉=1m annual, every square metre of soil surface
3, have the possibility that reaches the percolate zero release by processing.
3. implementation cost of the present invention is low, especially when the final coverage rate of landfill yard was implemented, its soil layer and vegetation in fact were the necessary component of final coverage rate, therefore only need increase irrigation ditch and can handle with corresponding percolate irrigation transmission ﹠ distribution drainage facility, its cost of investment is quite cheap; And no matter at final coverage rate, still implement to handle outside the venue, its running cost only is the power charge of water delivery, than the membrane treatment appts etc. of complexity, very big saving is also arranged.
4. the pollutent of percolate and the part water yield when application method of the present invention is handled, have considerable part to obtain resource utilization, and moisture, ammonia nitrogen are utilized by plant-growth, but are converted into the biomass of renewable resources; Soil ulmin is retained in the soil, makes soil water-retaining, protects fertile characteristic improvement.Therefore, the present invention is the treatment process that has the resource utilization effect concurrently.
5. the present invention adopts chlamydate irrigation ditch, the mode of infiltrating by the inferior surface of percolate realizes irrigating processing, the irrigation of percolate in the vegetation soil layer compared with conventional sewage irrigation modes such as sprinkling irrigations with traditional surperficial cross flow, percolate is not directly contacted with atmosphere and soil layer surface, the foul smell that can reach control irrigation process discharges and to the purpose of the pollution of soil layer overland flow, has controlled the secondary pollution for the treatment of processes effectively.
Description of drawings
Fig. 1 is a process flow sheet of the present invention
Fig. 2 is vegetation-pedosphere diagrammatic cross-section that the final coverage rate of landfill yard of the present invention is arranged
Fig. 3 is the vegetation-pedosphere diagrammatic cross-section of ground configuration outside the venue of the present invention
Label declaration in the accompanying drawing is as follows:
The 1-irrigation ditch covers clay; 2-irrigates perforated pipe; The 3-rubble is filled; The 4-irrigation ditch; The 5-agric; The 6-fill stratum; 7-clay closing layer; The 8-rubble is adjusted layer; The 9-waste layer; The 10-earthwork grid; The 11-HDPE film; 12-sand water conservancy diversion layer.
Embodiment
Embodiment 1
See also Fig. 1 and 2.Utilize the final coverage rate of landfill yard to implement the present invention, at first arrange of the present invention by irrigating vegetation-soil treatment facility that water carrying services, vegetation and pedosphere constitute at the final coverage rate of landfill yard.Because the final coverage rate of landfill yard is progressively to form with accumulation working time of landfill yard, therefore, corresponding Facilities Construction also should be carried out by stages, considers from the rationality of technique and economy aspect, the final wide coverage that downpayment construction can form at landfill yard is in 10,000m
2Shi Qidong, later every formation 10,000m
2About final coverage rate, can implement the first phase extension project.
Concrete construction step and method:
One. irrigate water carrying services.Usually when building the final coverage rate percolate vegetation of downpayment landfill-soil treatment facility, the water quality of landfill yard effusion does not still reach long level of filling out the percolate in age, the therefore water outlet of pending percolate for handling through biological treatment device.It irrigates water carrying services by irrigating storage pond, and transferpump and water pipe are formed.The volume of storage pond should be day 1.5 times of maximum irrigation volume of vegetation-soil treatment facility that this landfill yard finally builds up.Construction scheme is paid the utmost attention at the total storage pond of landfill percolate and is separated the corresponding volumetrical method structure of regulating and storing, and then can make up separately as infeasible, and construct, liner HDPE anti seepage membrane by concrete depositing or base soil structure in order to adopt for method.Transferpump is used for the percolate in the storage pond is delivered to irrigation ditch 4, and the water delivery flow of transferpump should satisfy two conditions: the one, should satisfy an irrigation ditch of in 0.5 hour, finishing to control irrigated area maximum, by maximum day duty load (15L/m
2D) requirement of water delivery.The 2nd, should satisfy and in 2 hours, finish to all irrigation ditches, requirement by (the same) water delivery of maximum day duty load, should adjust two conditions simultaneously during design, get its large one as the design discharge index, the pumping head index of design can hydraulic calculation method be definite routinely according to landform (discrepancy in elevation) and water pipe parameter, the transferpump pattern is preferentially selected impeller pump, when pressure head can not satisfy, can consider to select for use spiral pump.Water pipe is pressure water pipe Hydraulic Design Method design and construction routinely.
Two. irrigate the facility of water distribution. this part facility is arranged on the face of the waste layer 9 that plans finally covers in the landfill yard. and at first the requirement that covers by the end of sanitary landfill is carried out the compacting leveling to waste layer 9, lays rubble and adjusts layer 8 and clay layer 7 (being not less than the thick compacting clay of 0.3m) of closing; Then, laying is not less than the thick fill stratum of 0.3m 6, and (soil property does not have particular requirement, but the stone volume ratio is less than 5%), re-laying on it to be not less than the usefulness that irrigation ditch 4 is made percolate irrigation water distribution is set on the thick agric of 0.3m 5. agrics 5 again. irrigation ditch 4 is the degree of depth≤0.2m, the Tu Gou of width 0.2~0.4m, 80% of its degree of depth is filled the graded broken stone of particle diameter 20~40mm and is filled 3, the above irrigation ditch of rubble covers clay 1 isolated percolate and directly contacts with atmospheric, and preventing that rainwash from flowing into. irrigation ditch 4 inlets are connected with input channel, and percolate can be transfused in the irrigation ditch 4; Irrigation ditch 4 arranges that according to the level line on soil layer surface the spacing that irrigation ditch is 4 is 5~10m, when agric 5 surface gradients are big, and capping, otherwise, get lower bound.
Three. vegetation plantation: the three kind of plant types that constitute vegetation are: each a kind in warm, cold season growth form herbage, a kind of fast-growing tree.The preferred plant kind is: warm season growth herbage: Bermuda grass, cold season growth herbage: Festuca Arundinacea, fast-growing tree: the coldest monthly mean temperature in locality≤5 ℃, speed is given birth to easy poplar, other areas, Folium seu Cortex Nerii.The vegetation seeding method: herbage is adopted the mode of seed sowing, and fast-growing tree adopts sapling transplanting method, height of seedling 0.3~0.5m, strain spacing 2~4m; The sowing time order: should determine that Guangdong and Guangxi Provinces, Fujian, Hainan, Yunnan district: all can sow the whole year by geographical zone, three kind of plant can be sowed (planting) in batches and finish in 1 month.Huaihe River except that above-mentioned provinces and regions, on the south the Qinling Mountains zone: it is initial when month being 3~May construct, sows (planting) Bermuda grass and fast-growing tree earlier, to after-culture Festuca Arundinacea again in September; It is initial when month being 6~August to construct, and sowing Bermuda grass earlier to after-culture Festuca Arundinacea again in October, is planted fast-growing tree after March in the coming year; Constructed when being 9~November in initial month, broadcast Festuca Arundinacea earlier, plant fast-growing tree March in the coming year, broadcast Bermuda grass May; Constructing initial month is 12~February: should not sow, be delayed to and plant by aforementioned manner March in the coming year.Huaihe River, to the north of the Qinling Mountains, on the south the Great Wall zone: the initial moon of construct is 4~May, 3~May of a same zone; Constructing initial month is 6~August: 6~August of a same zone; Constructing initial month is 9~October: 9~November of a same zone; Constructing initial month is should not sow for 11~March, and being delayed to April in the coming year initial month was that the mode in 4~May is finished sowing by construction.Zone to the north of the Great Wall: only need plant Festuca Arundinacea and fast-growing tree 2 kind of plant, planting season: Festuca Arundinacea is 4~September, and fast-growing tree is 4~June, and other months should not be sowed (planting).Above-mentioned no matter which kind of planting patterns, after new plant sowing (planting), all need carry out about 1 month maintenance irrigation, should handle percolate with the plan of diluting 2 times during this time irrigates vegetation as former water, treat fraction of coverage>80% of vegetation to soil layer, after fast-growing tree exposes sprouting, begin again to handle irrigation by the normal handling load.
Four. comprise the irrigation operation of monitoring.The operation that percolate vegetation-soil irrigation is handled has two main aspects, and the one, load control, the 2nd, vegetation maintenance.Irrigate load control, implement by the duty of controlling every day, water-quality guideline and weather condition that the accounting of the water yield is irrigated in the storage pond with proxima luce (prox. luc) are determined.At first should be according to water-quality test COD (C as a result
COD) ammonia nitrogen (C
Ammonia nitrogen) and corresponding upper limit load value [COD] and [ammonia nitrogen], press COD and ammonia nitrogen loading and allow duty (V
CODAnd V
Ammonia nitrogenBut) calculating formula measuring and calculating duty:
(in the formula: C
CODAnd C
Ammonia nitrogenUnit be: g/L, [COD]=24g/m
2D, [ammonia nitrogen]=18g/m
2D, V
CODAnd V
Ammonia nitrogenUnit is L/m
2D).Then, press weather condition and determine to allow water yield load (V
L), that is: during temperature on average 〉=15 ℃, 15L/m
2D, during temperature on average<15 ℃, 8L/m
2D during temperature on average<4 ℃, stops to irrigate; Simultaneously, when daily rainfall greater than 15mm, stop to irrigate, rainfall amount 8-15mm irrigates by 1/2 of aforementioned water yield load.At last, contrast V
L, V
CODAnd V
Ammonia nitrogen, get the duty of its little person for next day.
Vegetation maintenance, main operation are that herbage is gathered in and fast-growing tree is carried out beta pruning, and purpose is to stimulate its biomass to increase, to absorb more nutrition; The plant biomass of results can be used as the fuel utilization. maintenance process: and 1) herbage, when surpassing 20cm, blade length should gather in, stay after cutting about Chuang 5cm; 2) fast-growing tree, carry out the 1st beta pruning the autumn of planting after 2 years, wipes out rate about 60%, and later on annual autumn is by the same rate of wiping out beta pruning 1 time.
Embodiment 2
See also Fig. 1 and 3.Implement the present invention by arrangement outside the venue, advantage is the restriction that is not subjected to landfill yard landfill process, and the vegetation-pedosphere that can form all percolates that produce in being enough to handle once is used for irrigating to be handled; But shortcoming is, because irrigating facility is positioned at outside the landfill yard, irrigates the isolation that water seepage lacks the landfill site seepage prevention layer, in order to reach the phreatic purpose of protection, must be under the pedosphere of irrigating ad hoc one deck impervious barrier.
From reducing investment outlay and the aspect of floor space is considered, this programme also can combine application with the scheme that vegetation-pedosphere landfill yard coverage rate is arranged, that is: elder generation builds the irrigating facility of layout outside the venue of certain area, to solve the percolate processing demands of landfill yard initial operating stage, simultaneously along with the finally increase of area coverage in the field, the irrigating facility that is arranged on the final coverage rate also is set inside, the diafiltration liquid measure simultaneous growth that irrigation processing power and landfill yard need be handled, (annotate: the percolate generation of landfill yard is lower in the early stage usually to reach the purpose that satisfies the percolate processing demands in the whole service lifetime, progressively increase subsequently, middle and later periods in its operation peaks, and can fall after rise again after again).
Concrete construction step and method:
One. irrigate water carrying services with above-mentioned embodiment 1.
Two. vegetation-soil and irrigation cloth drainage facility.At first reply ground is outside the venue carried out smooth; Then, (the sand particle diameter<1cm), interval 10m lays a perforated pipe (concrete or HDPE tubing) in its layer, to draw runoff to lay 0.2m sand water conservancy diversion layer 12 thereon earlier.Cover clay 0.2m, also smooth on the sand water conservancy diversion layer 12 again, on clay, lay 1mmHDPE film 11 (two-sided subsides 200g/m again
2The geotextile protection), establishes the earthwork grid 10 of 0.5cm on the HDPE film 11, derive as layer of displacement and irrigate water seepage.The lowest part of layer of displacement should be established french drain and collect water seepage and conflux to the water seepage storage pond.The water seepage storage pond adopts the mode of digging pit to make up, the antiseepage of liner 1mmHDPE film, the volume in pond should be 1.5 times of vegetation-soil facility percolate processing in maximum day capacity, establishes outer comb (band valve) of water seepage and water seepage reflux pump (being connected to an interior percolate storage pond) in the pond; Be provided with fill stratum 6 and agric 5 above the earthwork grid 10 successively.Fill stratum 6 thick 0.5m, arable layer 5 thick 0.3m.The irrigation ditch 4 of arable layer 5 is arranged identical with scheme 1 with the mode of constructing.
Three. the vegetation plantation, with scheme 1.
Four. irrigate and operate, with scheme 1, but the water (effluxing tube valve closes) of tackling every day in the water seepage storage pond is done once monitoring, after the affirmation water reaches emission request, opens and effluxes tube valve discharge water; Otherwise, then should open reflux pump, water is back to an interior storage pond, remake circular treatment.