CN103387288A

CN103387288A - Improved UCT sewage treatment plant

Info

Publication number: CN103387288A
Application number: CN2013102731789A
Authority: CN
Inventors: 张跃进; 赵永军; 王娟; 葛志刚; 张慧; 赵国华; 高树梅; 方应森; 保积庆; 徐劼
Original assignee: Jiaxing University
Current assignee: Jiaxing University
Priority date: 2013-07-01
Filing date: 2013-07-01
Publication date: 2013-11-13

Abstract

The invention discloses an improved UCT sewage treatment plant, in which sludge is returned back to not an anoxic zone in a tranditional UCT sewage treatment plant but an aerobic zone, therefore bad influence to nitrogen and phosphorus removal in anoxic zone of a UCT reactor because of large volume of dissolved oxygen and nitrate nitrogen in backflow sludge is avoided. The improved UCT plant has good effect to municipal sewage processing.

Description

A kind of improved UCT waste disposal plant

Technical field

The invention belongs to field of environment engineering technology, be specially a kind of novel improved UCT waste disposal plant.

Background technology

People, for the pay attention to day by day of environment, make sewage drainage standard improve constantly, and these sewage drainage standards all are subject to the protection of law and the supervision of public opinion.In China, nitrogen and phosphor contaminant are one of topmost pollutents, and their discharging all has been subject to strict supervision and restriction.A2/O technique has pollutant removal preferably in theory, and sludge settling property is good, consuming little energy.A2/O technique can remove a large amount of nitrogen pollutants by the nitration denitrification process, and by the process of anaerobic-aerobic and anoxic alternately, polyP bacteria can excessive absorption and discharged phosphorus to remove phosphor contaminant.But the drawback of A2/O technique is that in returned sluge, nitrate nitrogen enters anaerobic pond, destroys the anaerobic state of anaerobic pond and affects the phosphor contaminant clearance of system.So for above problem people, developed UCT technique.UCT technique is a kind ofly in China, to use sewage treatment process comparatively widely, and it is with higher cost performance, and comparatively stable treatment effect, obtained the favor of domestic a lot of sewage works.But existing UCT art breading effect also also has many improved places that are worth, and tracing it to its cause is to have a large amount of dissolved oxygens and nitrate nitrogen in returned sluge, thereby they can be back to the oxygen-starved area of UCT reactor and affect the reaction effect of oxygen-starved area.The removal of phosphor contaminant also has been subject to impact, because contain a large amount of nitrate nitrogen nutritive elements in returned sluge, they can impel the growth of non-polyP bacteria in oxygen-starved area.

Summary of the invention

The object of the present invention is to provide a kind of improved UCT waste disposal plant, it can avoid existing UCT because having a large amount of dissolved oxygens and nitrate nitrogen in returned sluge, and the Nitrogen/Phosphorus Removal of oxygen-starved area is caused detrimentally affect.

Technical scheme of the present invention is: a kind of improved UCT waste disposal plant, comprise anaerobic reactor, anoxic reacter, aerobic reactor, the settling pond that is connected successively by the sewage disposal order, between anaerobic reactor and anoxic reacter, and be respectively equipped with the internal reflux pipe between anoxic reacter and aerobic reactor, it is characterized in that: the returned sluge after settling pond is communicated with aerobic reactor.

Beneficial effect: exist a large amount of dissolved oxygens to enter aerobic zone in returned sluge of the present invention, can promote in aerobic zone that microorganism is for the degraded of COD, exist a large amount of nitrate nitrogens to enter aerobic zone in returned sluge simultaneously, can promote to a certain extent the denitrification effect of microorganism in aerobic zone.The present invention has good treatment effect for municipal wastewater.

Description of drawings

Fig. 1: apparatus of the present invention form schematic diagram;

Fig. 2: hydraulic detention time and pollutants removal rate relation line, wherein a:COD and TP, b:TN, NH4+-N and KN;

Fig. 3: hydraulic detention time and pollutent specific removal rate relation line, wherein a:COD and TP, b:TN, NH4+-N and KN.

Embodiment

The present invention will be described in detail below by embodiment:

Embodiment

Fig. 1 is the UCT treating processes after improvement used in the present invention.In improved UCT treating processes, the mud of backflow has entered into aerobic zone, thereby has avoided the impact of dissolved oxygen (DO) for anoxic and anaerobic zone.The cubic capacity that is used for the device of pilot experiment is 128L, its anaerobic reactor 10L, anoxic reacter 26L, aerobic reactor 90L, settling pond 2L(Fig. 1).

(1) the become a mandarin character of municipal wastewater is as shown in table 1.In whole experimental period, every indices of testing once water inlet, water outlet and mud in 4 days, always have 36 groups of data.All Contaminant measurements are all to carry out according to the standard of American Public Health Association (APHA).Suspended solid amount (SS) and dissolved oxygen (DO) use respectively Surface Scatter7sc device (HACH, USA) and Z LLIG S-14device (HACH, USA) to measure.PH value and temperature use HACH GLI PH/ORP device (HACH, USA) to measure.The pH of sanitary sewage and DO will measure every day, and the scope of its typical pH value is 6.0 to 7.6, DO to remain on 1mg L-1 above (table 1) always.

Table 1:UCT water inlet character (mg L-1)

(2) as shown in Figure 2 a, UCT can keep very high COD clearance, its the highest can be in the hydraulic detention time 15h(phase III, 81-120 days, 21-30 organizes data) time reach 96%, yet specific degradation rate shows the trend of falling after rising, and its maximum value has reached 8.80 * 10-3h-1(Fig. 3 a) at hydraulic detention time 15h.In the activated sludge process process, COD clearance and hydraulic detention time always are directly proportional, yet in this experiment, the highest COD clearance does not appear at maximum hydraulic detention time 24h.Trace it to its cause, may be because under long hydraulic detention time condition (as 19h or 24h), the flow rate of current in anaerobism, aerobic, anoxic and settling pond, and aerobic internal reflux speed to anoxic and anoxic to anaerobism, and settling pond is to the sludge reflux amount of anoxic, there is slowing down and reducing in various degree in capital, and the quantity of the aerobic bacteria in aerobic like this zone just may be less, thereby affect the degraded of COD pollution.

(3) in Fig. 2 a, the clearance of total phosphorus (TP) is to fall after rising, and clearance is in the 19h(subordinate phase, and 41-80 days, 11-20 organizes data) time reach maximum value 85%.The specific removal rate of TP remain in whole experimentation low-level on, change not quite, reach maximum value 2.90 * 10-3h-1(Fig. 3 a) when hydraulic detention time 19h.Be only 54% at first stage TP average removal rate, but second and the phase III rise to 79% and 72%, fourth stage drops to suddenly 49% again.The optimum hydraulic detention time of this explanation is between 19 to 15 hours, and just coincide the generation time of this and polyP bacteria.Therefore, 19h is defined as best TP and removes hydraulic detention time.

In Fig. 2 b, the clearance of total nitrogen (TN), ammonia nitrogen (NH4+-N) and kjeldahl nitrogen (KN) is proportional to hydraulic detention time and pollutants removal rate.Hydraulic detention time 24h(first stage, 140 days, data set 1-10) time, TN, NH4+-N and KN reach respectively maximum material removal rate 72%, 76% and 78%.Their specific removal rate is (Fig. 2 b and Fig. 3 b) consistent with the variation tendency of pollutants removal rate, reaches respectively maximum value 1.70 * 10-3,1.85 * 10-3 and 2.05 * 10-3h-1 when hydraulic detention time 24h.

In sum, the clearance of TN, NH4+-N and KN always is greater than fourth stage in first stage and subordinate phase, so this result of study shows that when hydraulic detention time was longer, the UCT device had higher clearance for nitrogen-containing pollutant.

(4) the UCT technique after improvement of the present invention has reached effect preferably for the purification of city domestic sewage, but need aspect the removal of its flocculating settling characteristics at mud and NH4+-N and COD to improve.Optimum hydraulic detention time is 19h, and the clearance of COD, TP, TN, NH4+-N and KN can reach respectively 96%, 85%, 72%, 76% and 78% at this moment.

Claims

1. improved UCT waste disposal plant, comprise anaerobic reactor, anoxic reacter, aerobic reactor, the settling pond that is connected successively by the sewage disposal order, between anaerobic reactor and anoxic reacter, and be respectively equipped with the internal reflux pipe between anoxic reacter and aerobic reactor, it is characterized in that: the returned sluge after settling pond is communicated with aerobic reactor.

2. improved UCT waste disposal plant as claimed in claim 1, it is characterized in that: the cubic capacity of device is 128L, wherein said anaerobic reactor volume 10L, anoxic reacter volume 26L, aerobic reactor volume 90L, settling pond volume 2L.