(1) The selection of parameters according to load insufficient, choose the parameter scope provided too much [such as literature recommend Nv = 0.1 ~ 1.3 kgBOD5 / (m3 d.)], and did not consider water temperature and feed water quality, sludge age, active sludge quantity and SBR pool elements such as geometry size of load and ChiRong influence;
(2) The load method will be the continuous aeration ChiRong calculation method is used to remove the second pond function ChiRong SBR calculation, the difference being theory, the results for the small;
(3) In the calculation formula in all appeared of SVI, MLSS, Nv, Ns and other sensitive parameters of change, it is hard to be all at the same time according to the assumption that experience, ignore the obvious influence on the substrate, and will lead to between parameters is not consistent even contradictory phenomenon;
(4) The aeration time load method and dynamic design method in tried to introduce effective aeration time ta of SBR ChiRong have the impact, but because of the dynamics theory and calculation by, the assumption is that the boundary conditions not completely adapted to the actual all stages of the reaction process, will remove the organic carbon is limited only on good oxygen phase of aeration role, and to ignore the other the aeration stage of organic carbon removal of effects, resulting in the same load conditions ChiRong SBR income dramatically too large.
The above problems are not conducive to the SBR sewage to the effective treatment, and many more are also can't plan reflect the amount of SBR, will draw the investment on the high side or the result of low.
According to the problems, and put forward a set amount of sludge in the total of the main parameters of the ChiRong SBR integrative design method
The total amount of sludge 3.4 integrated design method
The method is to provide SBR reaction pool certain active sludge quantity for the premise, and meet the conditions for SVI, guarantee in the settlement for and drainage stage last stage in the distance and precipitation area of settlement, the lowest depth calculated the least sludge settling the volume, and according to the cycle of water into calculate water storage capacity, which is combined ChiRong SBR asked. From this and checking the activity of aeration time sludge concentration and minimum under the water depth of the sludge concentration, the rationality of the calculation results with discrimination. Its computation formula is:
TS = naQ0 (C0-Cr) tT · S (10)
Vmin = AHmin quartile TS · SVI · 10-3 (11) Hmin = Hmax-Δ H (12) V = Vmin + Δ V (13)
Type of ? TS-a single SBR pool total dry sludge, kg TT · S-- in sludge age, d A few HePing area-SBR pool, m2
Hmax, Hmin-respectively for the highest water level when aeration and precipitation at the end of the lowest water level, m
Δ H-the highest water level and lowest water level is poor, m
Cr-effluent BOD5 concentration and concentration of suspended substances in water solubility BOD5 concentrations of the poor. Its value is:
Cr = Ce-Z · Cse · 1.42 (1-ek1t) (14)
Type of Cse-out of the water ? concentration of suspended substances, kg/m3 K1-the oxygen consumption rate, d-1 T-BOD experiment time, d
Z-active sludge heterotrophic bacteria in proportion, the value for: Z = B-(B2-8.33 Ns · 1.072 (15-T)) 0.5 (15)
B = 0.555 + 4.167 (1 + TS0 / BOD5) Ns · 1.072 (15-T) (16) Ns = 1 / a · tT · S (17)
Type of ? a-sludge production coefficient, namely units produced BOD5 excess sludge quantity, kgMLSS/kgBOD5, its value is:
A = 0.6 (TS0 / BOD5 + 1)-0.6 x 0.072 x 1.072 (T-15) 1 / [tT · S + 0.08 x 1.072 (T-15)] ? (18) Type of TS, BOD5-respectively for water floating in the solid concentration and BOD 5 concentration, kg/m3
T-sewage water temperature, ℃
By type (9) of the calculation Vmin are at the same time satisfy the active sludge sedimentation geometry area and established under the condition of precipitation for settlement distance, this value will be greater than the current methods of Vmin calculated.
It must be pointed out that the actual sludge sedimentation distance should consider for the settlement of drainage in effect, this action distance called protection highly Hb. At the same time, SBR in the pool from the mixture mixed into a fully dynamic static precipitation in initial 5 ~ 10
min sludge is still in the turbulent state, then it gradually become compressed settlement drainage lasted until the end. The relations between them by next type can be said:
Vs (ts + td-10/60) = Δ H + Hb (19) Vs = 650 / MLSSmax · SVI (20)
By type (18) generation into the type (17) and the corresponding transformation rewrite for: [650 · A · Hmax/TS · SVI] (TS + td-10/60) = Δ V/A + Hb (21) Type of-sludge sedimentation rate vs, m/h
MLSSmax-when Hmax water was the MLSS, kg/m3
Ts, td-respectively for sludge precipitation diachronic and drainage lasted, h
Type (19) SVI, Hb, ts, td all can according to experience hypothesis, ts, Δ V are known, Hmax based on wind pressure blower ending drive-three tanks or effective water depth Settings, A for may ask, and get Δ H, in the licensing of drainage within the scope of the ultrasonic guarantee allowed protection level. Therefore, by type (10), (11) can be obtained respectively Hmin, Vmin
3 In the problems of developing SBR and reaction ChiRong.
Compared with the traditional continuous flow of activated sludge, SBR process is a still in the development stage, perfect the technology, a lot of research work is just starting, lack of scientific design basis and method and mature operation management experience, in addition, SBR characteristic of oneself further solve the difficulty of the problem.
In the present stage of SBR process of development, mainly exist in the following problems: <1> Basic research
(1) In the stable state of sewage sludge under the theory of microbial metabolism research; (2) About anaerobic and anaerobic state of microbial activity and alternately repeatedly on the distribution of the population;
(3) At the same time and nitrogen phosphorus removal of microbial mechanism research. <2>Project design
(1) lack of scientific and reliable design mode;
(2) the operation mode of the selection and design method apart