SBR的DAT－IAT法新型工艺及设备的研究与应用 · System )、CASS(Cyclic Activated Sludge System)、CAST(Cyclic Activated Sludge Technology) 、 DAT-IAT(Demand Aeration

水世界-中

国城镇水网

http://www.chinacitywater.org

SBR 的 DAT－IAT 法新型工艺及设备的研究与应用

张大群王秀朵

天津市市政工程设计研究院

【摘要】本文通过介绍新型的 DAT－IAT 工艺的工作原理、工作过程、

工艺特点，以及该工艺主要的工艺参数和机械设备，表明了 DAT-IAT 系统是

普通活性污泥法与传统 SBR 法有机结合的一种新型工艺。该工艺具有增加了

工艺处理的稳定性、提高了池容利用率、提高了设备利用率和增加整个系统

灵活性等特点。另外，重点研究了 DAT-IAT 工艺处理系统中的关键设备滗水

器。介绍了三种滗水器：机械式滗水器、虹吸式滗水器、自力（浮力）式滗

水器的机械结构及特点。工程实例证明所发明的 DAT-IAT 工艺是一种高效的

污水处理新型工艺。

关键词：SBR 工艺；DAT－IAT 工艺；机械设备；滗水器。

一、前言

SBR(Sequence Batch Reactor) 工艺在同一反应池中，完成进水、反应、

沉淀、滗水、排泥等工序，与其它处理工艺相比，SBR 工艺使污水处理构筑

物大大简化。SBR 工艺早在 1914 年即已开发，但由于当时人工管理繁琐，监

测手段落后，使其难以推广应用。近年由于微机在自控方面的广泛应用，同

时也由于开发了在线溶解氧测定仪、水位计等精度高并且对过程控制比较经

济的水质检测仪表，污水处理厂的运行管理逐渐实现了自动化，SBR 工艺以

其独特优势引起广泛注意，近年来得以迅速推广，成为目前世界上污水处理

—1—

水世界-中

国城镇水网


—2—

技术中的热门工艺，澳大利亚近 10 多年来建成采用 SBR 工艺的污水处理厂近

600 座，中、大型的 SBR 污水处理厂也日益增多。我国目前在云南省昆明市

已有两座采用 SBR 工艺的大中型污水处理厂，运行情况良好。天津经济技术

开发区10万吨／日采用SBR工艺的污水处理厂也于1999年底成功投入运行。

抚顺三宝屯污水处理厂 25 万吨／日采用 SBR 工艺正在开工。工业废水处理厂

在国内外使用更为广泛。

随着 SBR 工艺在工程设计中的应用，其技术也得到了长足的发展。由传

统的 SBR 工艺发展了 ICEAS(Intermittent Cyclic Extended Aeration

System )、CASS(Cyclic Activated Sludge System)、CAST(Cyclic Activated

Sludge Technology) 、 DAT-IAT(Demand Aeration Tank-Intermittent

Aeration Tank)、MSBR 等工艺，这些工艺各有各的特点，大大丰富了 SBR 工

艺的内容。各种 SBR 工艺的分类如下：

1）按进水方式分为：连续进水和间歇进水；

2）按负荷分为：高负荷和低负荷：

3）按反应池型式分为：完全混合式和循环水渠式；

4）按进水曝气与否分为：限制曝气、非限制曝气、半限制曝气；

下面主要介绍新型的 DAT－IAT 工艺及设备。

二、DAT－IAT 系统工艺的工作原理

SBR 法是活性污泥法的变法，是依靠活性污泥微生物的活动来净化污水

的，这一点 SBR 工艺与传统活性污泥工艺完全一致，只是运行方式不同，传

统工艺采用连续运行方式，污水连续进入处理系统并连续排出，系统内每单

元的功能不变，污水依次流过各单元，从而完成处理过程。SBR 工艺一般采

用间歇运行方式，污水间歇进入处理系统并间歇排出。系统内只设一个处理

水世界-中

国城镇水网


单元，该单元在不同时间发挥不同的作用，污水进入该单元后按时间顺序进

行不同功能的处理。

DAT－IAT 系统的主体构筑物由一个连续曝气池和一个间歇曝气池串连

而成。一般情况下，DAT 连续进水、连续曝气，其出水连续流入 IAT，在 IAT

完成反应、沉淀、出水等工序。其典型工艺流程如图所示。

沉砂外运

—3—

进水

回流污泥

剩余污泥

泥饼外运

排入水体

分砂鼓风机房

格栅进水泵房

贮泥池

加氯间

脱水机房

沉砂池 DAT 反应池 IAT 反应池

DAT－IAT 系统典型工艺流程

DAT－IAT 系统是 SBR 工艺完善和发展的新型式，它的反应机理以及污染

物去除机制与连续活性污泥法相同，DAT 池为预反应池，也称为连续曝气区，

池中水流呈完全混合流态，绝大部分有机物在这个池中降解。IAT 相当一个

传统的 SBR 池。但进水为连续流。

三、DAT－IAT 系统的工作过程

DAT 池和 IAT 池串联组成，DAT 连续进水，连续曝气（也可间歇曝气），

IAT 也是连续进水，但间歇曝气，清水和剩余活性污泥均由 IAT 池排出。和

典型的 SBR 反应池一样，IAT 池运行操作由进水、反应、沉淀、出水和待机

五个阶段组成。

水世界-中

国城镇水网


—4—

1.进水阶段

与典型的 SBR 工艺不同的是，DAT－IAT 系统的处理水是连续进入 DAT，

然后进入 IAT。连续进水使对进水的控制大大简化，这样的双池系统也

避免了水力短路。

2.反应阶段

反应阶段分两部分：在 DAT 中连续曝气，池中水流呈完全混合流态，绝

大部分有机物在这个池中降解。经 DAT 处理后的混合液通过两池间的导流系

统连续不断进入 IAT，IAT 间歇曝气进一步去除有机物，使处理出水达到排

放标准。

3.沉淀阶段

沉淀阶段只发生在 IAT。当 IAT 停止曝气后，活性污泥絮体静态沉淀与

上清液分离，DAT 注入 IAT 的混合液流速很低，对 IAT 不产生扰动，因而其

沉淀效率显著高于一般二沉池的动态沉淀。

4.排水阶段

排水阶段只发生在 IAT，当池水位上升到最高水位时，沉淀阶段结束，

设置在 IAT 末端的滗水器开动，将上清液缓慢地排出池外，当池水位降到最

低水位停止滗水。

5.待机阶段

在 IAT 池滗水后完成了一个运行周期，两周期间的间歇时间就是待机阶

段。该阶段可视污水的性质和处理要求决定其长短或取消。

四、DAT－IAT 系统的特点

1.传统 SBR 工艺的特点

SBR 工艺是一种控制的非稳态系统，即采用某些方法将系统的非稳态行

水世界-中

国城镇水网


—5—

为限制在一定范围内。传统的活性污泥法则是一种无控制的非稳态系统。

存在于生活、工业污水，垃圾填埋渗出液，地下水以及土壤中的污染物，

可以分为有机物或无机物，有毒物或无毒物，密度高于水或低于水的物质，

易溶于水或难溶于水的物质以及可生物降解或不可生物降解的物质。这些自

然地而且非常剧烈地随着时间或空间的改变而改变，具有非稳态的特性。这

些自然地而且非常剧烈的变化常常与环境的不稳定性相关。传统的理论认为：

稳态是保证出水水质稳定并低于一定标准的必要条件。因此，在设计处理工

艺时，人们常把这些随机的变化和潜在的非稳态行为假设为稳态。许多工程

人员在设计处理构筑物时，采用流量平衡并不能有效地抵消质量流速的变化。

这种做法使这些系统变为无控制的非稳态系统。实际运行中，无控制的非稳

态系统只能满足简单的处理要求，如去除 COD 和 SS 等，而对于去除 N、P 等

则无能为力。N 、P 等物质的去除要求更好地控制水污染物的不稳定性。这

在无控制的非稳态系统，是无法实现的。

SBR 相对于连续流系统还有许多其它方面的优点。首先，这种反应器运

行灵活简洁。它可以配合不同的进水水质调整运行模式。第二，SBR 流态上

属于完全混合，而在有机物降解方面却是时间上推流。因此为了达到较高去

除率而只需调整反应时间。这样大大减少了占地，特别适合中小型水厂。第

三，SBR 的沉淀阶段使泥水有效分离，出水悬浮物浓度低，无需另设澄清池。

第四，SBR 工艺中无二沉池及回流污泥系统，很多情况还可不设初沉池，因

而基建费用低，占地少。

SBR 工艺经过近年 10 多年的深入研究和发展已经基本完善，但仍存在着

一些不尽人意的地方。首先，间歇进水使处理工艺缺乏连续性。若使水处理

连续运行，需要设多池系统，增加投资。其次，对于一些高浓度难降解的有

水世界-中

国城镇水网


—6—

机废水则需要较长的反应时间。再次，SBR 工艺操作运行较为复杂，必须采

用自动控制，附属设施较多。

2.DAT－IAT 系统的特点

DAT－IAT 系统是普通活性污泥法与传统 SBR 同有机结合的一种型式，整

个系统有 SBR 工艺的优点，又改进了 SBR 工艺的不足，具有以下特点：

1）增加了工艺处理的稳定性：DAT 起到了水力均衡和防止连续进水对出

水水质的影响，特别是在处理高浓度工业废水时，DAT 连续曝气加强了系统

对难降解有机物的降解，相对缩短了运行周期。DAT 池连续曝气也使整个系

统更接近于完全混合式，更有利于消除高浓度工业废水中毒性物质或 COD 浓

度过高积累而带来的不良影响。

2）提高了池容的利用率：对于曝气池和二沉池合建的污水处理构筑物

来说，在保留沉淀分离效果的前提下，尽可能提高曝气容积比，与传统 SBR

法及其它变型方法来比，由于DAT－IAT中DAT池连续曝气和IAT的间歇曝气，

使该工艺方法的曝气容积比是最高的。

3）提高了设备的利用率：由于 DAT 池连续进水，因此不需要增设进水

的闸阀及自控装置；DAT 池连续曝气，减少了整个系统的曝气强度，提高了

曝气装置的利用率，所需鼓风机的额定风量和功率也减小了。

4）增加了整个系统的灵活性：DAT－IAT 系统可以根据进、出水量、水

质变化来调整 DAT 池与 IAT 池的工作状态和 IAT 池的运转周期，使之处于最

佳工况，同时也可以根据脱氮除磷要求，调整曝气时间，创造缺氧或厌氧环

境。

水世界-中

国城镇水网


—7—

五、主要工艺设计参数

序号设计参数名称取值备注

1 池子个数 3 座以上小规模时取 3～6 座

大规模时取若干组，每组 3 池

2 有效水深 3～7m

3 回流比 50%～200%

4 污泥负荷 0.05～0.1kgBOD/kgMLSS*d 采用低负荷运行

5 混合液污泥深度 3～5g/l

6 泥龄 20～30d

7 耗氧量 1.3～2.0kgO2/kgBOD

8 周期工作时间 3. 4. 6. 负荷小时，周期时间长

9 排出比 1/3～1/6

六、DAT－IAT 工艺的 6种专用机械设备及滗水器开发

DAT－IAT 工艺处理系统中主要用 6 种专用机械设备，这是：进水泵房粗

格栅机；旋流或平流除砂机；沉砂池细格栅机；曝气系统设备（中大型用鼓

风机带微孔曝气、小型厂用浮动式大行程曝气机）；滗水器；浓缩脱水机。滗

水器是研究开发的重点。

由于 SBR 反应池排水的不连续性，决定了排水装置应具备有：当排水时

能将上清液均匀地排出池外，而不搅动活性污泥；而在进水，反应、沉淀工

序阶段不影响工艺进行。滗水器是 SBR 工艺最常采用的排清水设备，它能从

静止的池表面将澄清水滗出而不搅动沉池，确保出水水质。滗水器具备有对

水量变化的可调节性，有良好的水力机械性能，又能随水位变化而自动、平

稳的升降。

目前国内外污水处理设备专家对滗水器作了大量的研究工作，研究出了

多种动力形式的滗水器，但归纳起来主要可分三种类型：机械式滗水器；

虹吸式滗水器；自力（浮力）式滗水器。简述如下：

水世界-中

国城镇水网


1. 机械式滗水器

机械式滗水器国内现主要有两种形式，旋转式和套筒式。旋转式滗水器

由电动机、减速机执行装置，四连杆机构，载体管道，浮子箱（拦渣器），淹

没出流堰口，回转接头等组成。通过电动机带动减速机及执行装置和四连杆

机构，使堰口绕出水管做旋转运动，滗出上清液，液面也随之同步下降。浮

子箱（拦渣器），可在堰口上方和前后端之间形成一个无浮渣或泡沫的出流区

域，并可调节的堰口之间的距离，以适应堰口淹没深度的微小变化。

机械旋转式滗水器

套筒式滗水器有丝杠式和钢丝绳式两种，都是在一个固定的池内平台上，

通过电动机带动丝杠或滚筒上的钢丝绳，牵引出流堰口上下移动。堰口下的

排水管插在有橡胶密封的套筒中，可以随出水堰上下移动，套筒连结在水总

管上，将上清液滗出池外。在堰口上也有一个拦浮渣和泡沫用的浮箱，采用

剪刀式铰链和堰口连接，以适应堰口淹没深度的微小变化。

—8—

水世界-中

国城镇水网


机械旋转式滗水器外形图机械套筒式滗水器

1－底板下管道；2－直管及套筒管

2．虹吸式滗水器

虹吸式滗水器实际是一组淹没出流堰，是由一组垂直的短管组成，短管

吸口向下，上端用总管连接，总管与 U 形管相通，U 形管一端高出水面一端

低于反应池的最低水位，高端设自动阀与大气相通，低端接出水管以排出上

清液。运行时通过控制进排气阀的开闭，采用 U 型管水封，来形成滗水器中

循环间断的真空和充气空间，达到开关滗水器和防止混合液流入的目的。滗

水的最低水面限制在短管吸口以上，以防浮渣或泡沫进入。

虹吸式滗水器

3．自力（浮力）式滗水器

自力（浮力）式滗水器也有多种形式，如前所述的两种机械式滗水器也

—9—

水世界-中

国城镇水网


都可以制成自力式滗水器，不同的是它只依靠堰口上方的浮箱本身的浮力，

使堰口随液面上下运动而不需外加机械动力。按堰口形状可分为条形堰式、

圆盘堰式和管道式等。堰口下采用柔性软管或肘式接头来适应堰口的位移变

化，将上清液滗出池外。浮箱本身也起拦渣作用。为了防止混合液进入管道，

在每次滗水结束后，采用电磁阀，自力式阀关闭堰口，或采用气水置换浮箱，

将堰口抬出水面。

电磁阀式软管滗水器电磁阀式肘节滗水器

气水置换箱式滗水器自力阀式滗水器

七、工程实例

天津经济技术开发区污水处理厂日处理污水 10 万吨，污水主要来源于区

内生活污水和工业园区生产废水，设计进水水质为：BOD5150mg/L，

COD400mg/L，SS200mg/L，出水水质BOD530mg/L，COD120mg/L，SS30mg/L，同

—10—

水世界-中

国城镇水网


—11—

时要求去除NH3－N10mg/L由于开发区污水受区内工业生产影响，水质水量变

化幅度较大，通过方案比选，结合贷款国技术特点，选择了DAT－IAT工艺。

该厂已于 1999 年正式投产使用。

DAT－IAT系统共设六组池，每组池容积为：11000m3每组池长L＝80m，池

宽B＝32m，有效水深H＝4.3m，反应池最低水位时水深 3.75m，污泥负荷

0.052kgBOD/kgMLSS d，混合液浓度（MLSS）5g/L，IAT运行周期T＝3h（曝气、

沉淀、滗水各 1h）每组反应池中DAT和IAT体积相同，各长 40m，中间设两道

导流墙，为保持DAT内足够的混合液浓度，需从IAT将混合液回流到DAT，混合

液回流比最大可达R=4.0 在IAT两侧距导流墙 8米处设 2台潜污泵，每台流量

0.55-0.6m3/s，扬程 2 米。回流泵的开停由PLC按预设程序自动控制，停泵的

时间安排在滗水阶段。两台泵的回流污泥管在DAT内分为四个出口，位于池的

四个角，它们以高速沿池底喷向池中心，对全池起强烈搅拌作用，形成完全

混合流态，混合液经两道导流墙进入IAT。经过导流墙的混合液以很低的流速

从底部进入IAT，不会对IAT沉淀的污泥产生搅动。

采用鼓风曝气，曝气设备为膜片式微孔曝气器。曝气器总数 19838 个。

厂内设 4台单级高速离心风机，单台供气量Q＝18000m3/h，风压P＝0.5bar。

电机功率N＝400kw。

污泥产率系数为YT＝1.1，泥龄tDS=22d，每日污泥总产量体积V＝

2400m3/d，每池设有SS计，可根据污泥浓度值随时调整开泵的时间和周期，

确保反应池的正常运行。本工程排水选用虹吸式滗水器，每池 3 台，每台滗

水能力为 700m3/h。滗水器在最高水位时自动开动，最低水位时自动停止，滗

水器安装在IAT尾部。

水世界-中

国城镇水网


—12—

Study and Application of DAT – IAT of SBR New Process

Technology and Equipment

Zhang Daqiu Wang Xiuduo

Tianjin Municipal Engineering Design Institute

Abstract: Through the introduction of operation principle, procedures and technological

features of new process DAT – IAT as well as the main technological parameters and

mechanical equipment, this essay gave the presentation of DAT – IAT system to be a new type

of process characterized with the organic combination between plain activating sludge method

and conventional SBR process. This technology enhanced the stability of process and increased

the tank volume application efficiency, raised the equipment application yield and flexibility of

the whole system. Additionally, the key equipment named water filter in DAT – IAT treatment

process was studied mainly. Three kinds of water filter: mechanical water filter, siphon type

filter and floating type filter were introduced with their mechanical structures and features

respectively. The practical cases in engineering demonstrate that the invented DAT – IAT

process was one kind of new process for sludge disposal with high efficiency.

Key words: SBR process; DAT – IAT process; mechanical equipment; water filter.

I Preface

The process SBR (Sequence Batch Reactor) in one reaction tank will perform the procedures of

feeding water, reacting, precipitating, filtering and mud removing etc.. In comparison with

other disposal process, SBR process brings the sludge disposal with simplifying structure frame

a great deal. SBR process had been developed early in 1914, while because of the

over-elaborate manual management at that time and lagging measuring method, the technology

is difficult to be promoted for application. In recent years, due to the wide application of

computer in automatic control process, meanwhile, due to the development of in-line oxygen

measuring meters and water level meter with high accuracy and more economical process

水世界-中

国城镇水网


—13—

control water quality measuring meters, the operation and management in sludge disposal plant

has achieved automation gradually. SBR process has drawn a wide attention for its unique

advantage and has been promoted for application rapidly. It has become a hot process in sludge

disposal technology in the world. In recent ten years, nearly 600 plants have been constructed

with SBR process in Australia. More and more middle and large scale of SBR sludge disposal

plants have been built. At present, there are two large and middle scale of sludge disposal plants

with SBR process have been built in Kunming City Yunnan Province with well operation

condition. In Tianjin Economical and Technical Development Area, one sludge disposal plant

with daily handling capacity 100,000 tons with SBR process has been put into operation

successfully in 1999. Fushun Sanbaotun Sludge disposal plant is just running for operation with

handling capacity 250,000 tons/day with SBR process. SBR process has been widely used in

industrial waste water treatment both at home and abroad.

With the application of SBR process in engineering design, the technology has been developed

a great deal with the conventional SBR process to develop ICEAS (Intermittent Cyclic

Extended Aeration System), CASS (Cyclic Activated Sludge System), CAST (Cyclic Activated

Sludge Technology), DAT – IAT (Demand Aeration Tank-Intermittent Aeration Tank) and

MSBR process, and so forth. These processes have their own features with rich SBR process

contents. The classification of various SBR processes is as follows:

1) In feeding water mode: continuous feeding and intermittent feeding water type;

2) In handling load amount: high loading and low loading;

3) In reaction tank type: completely combined tank and cyclic water channel type;

4) In feeding water aeration or not: limit aeration, non-limit aeration, semi-limit aeration.

II Operation Principle of DAT – IAT system process

SBR process is the one which changed from activated sludge system process relying on the

moving of activated sludge microbe to purify the sludge water. This character is the same

completely for both SBR process and the conventional activated sludge process, only the

operation mode is different. The conventional one adopted continuous operation mode with

sludge water continuously feeding into the disposal system and also continuously flow out from

水世界-中

国城镇水网


the system. The function of every unit in the system remained unchanged with sludge water

flowing through various units resulted in the complete disposal procedure. SBR process

generally adopts intermittent running mode with intermittently feeding sludge water into the

treatment system and intermittently flowing out of the system. Only one treatment unit is

allocated in the system with playing different function in different time duration. After the

sludge water flows into the unit, the treatment in the unit with different function will be

performed according to time sequence.

The main structure of DAT – IAT system is consisted of one continuous aeration tank and one

intermittent aeration tank with serial connection. Generally, DAT is continuous feeding water

and continuous aeration, the outlet water will flow into IAT continuously carrying out the

procedures of reaction, precipitation and outlet of water etc.. The typical process flow chart is

as follows.

(See the next page beginning with the flow chart.)

handling out

precipitated sand inlet water sludge flow back Remained sludge Handling out

Sludge cake Draining into water system

Sand precipitation

Blower room

grid Inlet water pump room

DAT IAT Reaction Reaction

Tank Tank

Dewatering room Sludge storing tank

Chloride adding room

Sand precipitate

tank

DAT – IAT system typical flow chart

—14—

水世界-中

国城镇水网


—15—

DAT-IAT system is the new type of process developed and optimized from SBR process. Its

reaction principle and removing contaminated material mechanism is the same as continuous

activating sludge method. DAT is the pre-reaction tank, also named continuous aeration zone.

The water solution in the tank is complete mixing liquid status. Most of organic materials are

dissolved in the tank. IAT is equal to one conventional SBR tank, but featured with continuous

flowing of inlet water.

III Operation procedures of DAT – IAT system

DAT tank and IAT tank are connected in serial. DAT is continuous inlet water and continuous

aeration (can be intermittent aeration). IAT is also continuous inlet water but intermittent

aeration. Purified water and remained activated sludge will be drained out from IAT tank. The

same as typical SBR reaction tank, IAT tank operation is consisted of five durations including

inlet water, reaction, precipitation, outlet water, and waiting for operation.

1. Inlet water duration

Being different from SBR process, the treated water in DAT – IAT system is feeding into DAT

continuously and then into IAT. The continuous inlet water brings simplifying the control

procedures of inlet water, thus the double tank system also avoided short cut for water.

2. Reaction duration

The reaction duration is separated into two parts: continuous aeration in DAT with complete

mixing liquid of water flow in the tank. Most of organic materials are dissolved in the tank.

After the treatment in DAT, the mixed liquid will flow into IAT through flow guiding system

located between the two tanks. The intermittent aeration in IAT will remove further the organic

materials and make the treated water to reach the drainage standard.

3. Precipitation duration

The precipitation is only occurred in IAT. After aeration stopped in IAT, the activated

sludge-flocculating constituent is precipitated statically and separated from the above

水世界-中

国城镇水网


—16—

transparent liquid. The flow-rate of mixed liquid from DAT into IAT is very low without

producing interference to IAT. Therefore, the precipitation efficiency is obviously higher than

the general second precipitation tank dynamically.

4. Drainage water duration

The drainage duration only occurred in IAT. When the water level in the tank reached the

maximum level, the precipitation ended. The filter located at the end of IAT will start up. The

filter will drain the above transparent liquid out of the tank. When the water level dropped down

to the minimum level, water filtering stopped.

5. Duration waiting for operation

After the filtering in IAT tank, one operation circle completed. The time interval between the

two circles is the time waiting for operation. This duration can be determined longer or shorter

depending on the sludge water quality and treatment requirement.

IV Features of DAT – IAT system

1. Character of the conventional SBR process

SBR system is one unstable system under control, i.e. a certain method is adopted to limit the

unstable situation within a range in the system. The conventional activated sludge method is

one unstable status without any control.

The sludge water existed in daily life and industrial production, the released liquid from the

embedded garbage, under ground water and the contaminated materials in soil can be divided

into organic materials and inorganic material, toxic and nontoxic materials, the materials with

the density higher than water or lower than water, the materials with easy solved into water or

not solved into water, as well as the materials with biologically dissolved and non-dissolved.

All these materials are naturally and very strenuously changed with time and space changes,

also with unstable status character. These natural and strenuous changes are often relative to

environment non-stability. The conventional theory reckons that the stability is the precondition

水世界-中

国城镇水网


—17—

to guarantee the outlet water quality and be less than a certain standard. Thus during designing

the treatment process, these random and potential changes are assumed as stability. Many

engineering people adopt flow rate balance for their designing the treatment building, but this

cannot effectively compensate the changes of quality flow speed. This design makes the

systems to become unstable system without control. In practical running, the non-control and

unstable system can only meet the requirement of simple disposal, such as removing COD and

SS etc., but it cannot remove N and P. Removing N and P matters requires more better

non-stability of controlled water contaminated materials. This non-stability without control

cannot be achieved.

SBR has many advantages over the continuous flow system in other aspects. First, this reactor

has features of flexible and simple operation and can cooperate different inlet water quality with

regulating operation mode. Second, SBR belongs to complete mixing in its flow status and

promotes flow with time in organic material dissolving. Therefore, in order to achieve higher

removing rate, only the reaction time is required for adjustment resulted in reduction of landing

greatly. This feature is especially suitable to middle and small scale of water treatment plant.

Third, in the duration of precipitation of SBR, the sludge and water separate efficiently, the

density of floating material in outlet water is low without requiring clarifying tank. And

Furthermore, SBR process has no secondary precipitation tank and flow back sludge system. In

many conditions, the preliminary precipitation tank is not necessary to set bringing with low

construction cost and less landing area.

SBR process has been perfect basically through the deepening research and development for

more than ten years. Some points needed improving, however, still exist. First of all,

intermittent inletting water causes the process not to be continuous. If the water treatment

process is continuously running, multiple tank system will be needed to set up with increasing

investment. Secondly, some organic waste water with high density and difficult to be dissolved

will need longer time for reaction. Last, SBR process operation is more complicated and must

adopt automatic control with more attached devices.

水世界-中

国城镇水网


—18—

2. Features of DAT – IAT system

With the advantages of SBR process and improvement of SBR process weakness, DAT – IAT

system is one type of process combined with general activated sludge method and conventional

SBR process with the following features:

1) Enhancing the stability of process disposal: DAT plays the role of water force balance and

preventing the outlet water quality from being affected by continuous feeding water.

Particularly during the treatment of industrial wastewater with high density, the continuous

aeration of DAT strengthens the system to dissolve the difficult dissolved organic material and

shortens the running circle time relatively. The continuous aeration of the DAT system makes it

to be more likely to the complete mixed type with being favorable to removing the harmful

effect resulted from high density of toxic materials in industrial waste water or accumulation

caused by high COD density.

2) Increasing the utilization ratio of tank volume: In regard to sludge water disposal building

jointly built by aeration and secondary precipitation tank, under the precondition of remaining

precipitation separation effect, the aeration volume ratio is enhanced as much as possible.

Comparison with the conventional SBR process and other changed types of method, the

aeration volume ratio is the highest for its process feature of continuous aeration in DAT – IAT

tank and intermittent aeration of IAT.

3) Raising the utilization of equipment: Because of the continuous feeding water in DAT tank,

it is not necessary to add inlet water valve and automatic control unit; DAT tank continuous

aeration reduced the aeration strength of the whole system increasing the utilization of aeration

devices. The rated blowing strength and power of the required blower are also reduced.

4) Enhancing the flexibility of the whole system: The operation condition in DAT tank and

IAT tank and the running circle in IAT tank will be regulated according to the inlet and outlet

water quantity and quality of DAT – IAT system resulted in optimizing the working condition.

Meanwhile, with respect to the requirement of removing nitrogen and dephosphorization, the

aeration time will be adjusted to create the environment of lack of oxygen or disgust of oxygen.

水世界-中

国城镇水网


—19—

V Main processes design parameters

No. Name of Design parameters Value Remarks 1 Number of tanks More than 3 tanks 3 ~ 6 tanks put into

use for small scale 2 Effective water depth 3 ~ 7 m 3 Flow back ratio 50% ~ 200% 4 Sludge load 0.05 ~ 0.1kg BOD/

KG MLSS*d Adopt low load in running

5 Sludge depth of mixed solution 3 ~5g/l 6 Sludge age 20 ~30d 7 Oxygen consumption 1.3~20.dgO2/g\kgBOD 8 Operation circle time 3. 4. 6. Long circle time for

low load 9 Drainage ratio 1/3 ~ 1/6

VI 6 kinds of special mechanical equipment of DAT – IAT process and development of water

filter

There are 6 kinds of special mechanical equipment mainly to be put into use in DAT – IAT

process disposal system, i.e. thick grid in inlet water pump room; spiral flow and horizontal

flow removing sand machine; fine grid of sand precipitation tank; aeration system equipment

(middle and large scale of blower with minor hole aeration, floating type of long stroke aeration

machine for small scale of plant); water filter; condensing dewatering machine. The water filter

is the key point for research and development.

Because of non-continuous drainage of water in SBR reaction tank, it should be available for

the drainage equipment: the above clarified liquid could be drained in uniform out of the tank

without stirring the activated sludge during drainage; whereas the inlet water, reaction and

precipitation will not affect the proceeding of the process. Water filter is most frequently used

for drainage of clarified water in SBR process. It is able to filter out the clarified water out of

the tank without stirring the precipitation from the static surface of tank with outstanding water

mechanical properties and being changeable for lifting up and dropping down automatically and

stably with water level changes.

水世界-中

国城镇水网


For the time being, experts of water treatment equipment both home and abroad have made a

great deal of research work and developed water filters with multiple driving force modes. They

can be summarized in three types mainly: (1) mechanical type of water filter; (2) siphon type of

water filter; (3) self-force (floating force) type water filter. The description is delivered in brief

as follows:

1. Mechanical type of water filter

There are mainly two types of mechanical type of water filter domestically now, spiral type and

sleeve type. The spiral type of water filter is consisted of the following units: motor and reducer

as the executing devices, four lever mechanism, carrier channel, floating box (slag stopping

unit), submerged flow-out weir, rotating joint etc.. The sill rotating water pipe performs spiral

moving under driving by motor and reducer as well as the executing mechanism and four levers

structure. The above-clarified liquid will be filtered out and the water level drops down

synchronously. The floating box (slag stopping unit) can form a zone without floating particle

and foam at the above weir and between the front and rare end. The distance between the weirs

can be adjusted to be applicable to the minor changes of submerged depth of weir.

Mechanical spiral type of water filter

There are two types of sleeve type of water filter, i.e. guide screw and wire rope types. The

sleeve water filer, no matter which kind of it, is fixed on one platform inside the tank and driven

—20—

水世界-中

国城镇水网


by motor through guide screw and wire rope resulted in the up and down moving flow-out weir.

The drainage water pipe under the weir is inserted into the bushing with rubber sealed and

moving with weir. The sleeve is connected on head water pipe and through which the

above-clarified liquid will be filtered out of the tank. Above the weir, there is a floating box for

stooping floating slag and foam connected by hinge like shears in order to be suitable to the

minor changes of submerged weir depth.

—21—

Profile of spiral type Sleeve type of mechanical mechanical water filter water filter

1- bottom pipe； 2 - straight pipe and sleeve pipe

2. Siphon type of water filter

Siphon type of water filter is actually a submerged flow-out weir being consisted of a group of

vertical short pipes with downward sucking port and connecting with head pipe at upward port.

The head pipe is connected with U pipe on which one end above the water surface and the other

end lower the min. water level of reaction tank. The higher end has one automatic valve

ventilated with air, the lower end connected with outlet water pipe for flowing out the above

clarified liquid. During operation, the vacuum and air filling space alternatively inside the water

filter are formed through controlling open and close of inlet and outlet air valves and adopting

U type of pipe water sealing, to achieve the water filter on and off, preventing the mixed liquid

from flowing into. The min. water level of water filter is limited above the sucking port of short

pipes to prevent the accession of floating particle and foam.

水世界-中

国城镇水网


Siphon type of water filter

3. Self force (floating force) type of water filter

There are also multiple types of self force (floating force) type of water filter, such as the above

mentioned two types of mechanical type of water filter which can be formed into self force type

of water filter. The difference of this type of water filter from others is only the floating force is

relying on the floating box itself above the weir, in this way the level of weir moves up and

down without the additional mechanical force. This water filter can be separated into ribbon

type weir, disk type weir and pipe type weir for its shape of weir. The lower part of weir utilizes

flexible hose or elbow type of connector to be applicable to the changes of position moving

resulted in the clarified liquid flows out of the tank. The floating box itself also plays the role of

stooping slag. In order to prevent the mixed solution from flowing into the pipe line, after every

filtering water, solenoid and self forced valves will be used for close the weir, or adopt the air

and water displacement floating box to lift the weir above the water surface.

Solenoid type of hose water filter Solenoid type of elbow water filter

—22—

水世界-中

国城镇水网


Air & water displacement Self valve type of water filter water filter

VII Reference cases in Engineering

Sludge Water Plant in Tianjin Economical and Technical Development Area has the daily

disposal capacity 100,000 tons with the sludge water source from daily life sludge water in the

area and production waste water in industrial park. The design inlet water quality is BOD5

150mg/L, CODCr 400mg/L, SS 200mg/L. The design outlet water quality is BOD5 30mg/L,

CODCr 120mg/L, SS 30mg/L. Meanwhile it requires removing NH3 – N 10mg/L. Due to the

sludge water in Development area is affected by industrial production very much, the water

quality and water quantity change greatly. Through the solution comparison and selection,

combined together with the technical features of loan country, DAT – IAT process is selected in

the plant. The plant has been put into operation officially in 1999.

There are six sets of tank in DAT – IAT system with each tank volume 11000 m3, the tank

dimensions are the length L=80m, width B=32m, the effective water depth H=4.3m, the deepest

water depth 3.75m in reaction tank. The sludge load is 0.052kgBOD/kgMLSS•d. The mixed

solution density (MLSS) 5g/L, IAT operation circle time T=3h (aeration, precipitation, water

filtering are 1h respectively). The volumes both for DAT and IAT are the same for every group

of reaction tank with respective length 40m. Two sets of flow guiding wall in the middle are

located. In order to maintain the enough compound solution density in DAT, the compound

solution from IAT will be needed to flow back to DAT with the max. flow back ratio up to

R=4.0. On both sides of IAT with the distance to flow guide wall 8 meters, 2 sets of submerged

sludge pump are equipped with the flow rate 0.55 – 0.6 m3/s for each pump and stroke 2 meters.

The start and shutdown of the flow back pump will be controlled by PLC system automatically

—23—

水世界-中

国城镇水网


according to the preset program. The shutdown time will be arranged during the water filtering.

The flow back sludge pipes of the two pumps are separated into four exits in DAT located at the

four corners of the tank. The liquid will inject to the tank center along the tank bottom at high

speed playing stirring function to the whole tank and forming complete mixed liquid. The

mixed liquid will flow into IAT through two sets of flow guide wall. The liquid from flow guide

wall will access into IAT at very low speed from the bottom without generating sludge stirring

to IAT precipitation.

The blowing aeration is adopted with film sheet aerator or micro-hole aerator of the aeration

equipment. The total aerator number is 19838 sets. 4 sets of single class of high-speed

centrifugal blower are equipped inside the plant. The single set can supply air Q=18000m3/h,

blowing pressure P=0.5 bar. The motor power N is 400kw.

The sludge generation factor is YT=1.1, sludge age tDS=22d, the daily sludge output volume

V=2400m3/d. SS meters are allocated for each tank to adjust the pump startup and shutdown

time and circle at any time according to the sludge density to ensure the normal operation of the

reaction tank. This engineering select siphon type water filter for water drainage with three sets

for each tank and filtering capacity per set is 700m3/h. The filter will start automatically at high

water level and stop automatically at the low water level. The water filter is erected at the end

of IAT. 作者个人信息：

﹡ 张大群天津市市政工程设计研究院 (水)总工程师教授级高工天津水工业工程设备有限公司总经理

﹡ 王秀朵天津市市政工程设计研究院副总工程师教授级高工

论文信息：主题：污水处理工艺创新专题：其他与污水处理有关的最新技术成果题目：SBR 的 DAT-IAT 法新型工艺及设备的研究与应用关键词：SBR 工艺；DAT-IAT 工艺；滗水器

地址：天津市和平区营口道 239 号邮编：300050 E-mail：[email protected]电话：（022）27836375 传真：（022）27836420

—24—

mailto:[email protected]

Documents

SBR的DAT－IAT法新型工艺及设备的研究与应用 · System )、CASS(Cyclic Activated Sludge System)、CAST(Cyclic Activated Sludge Technology) 、 DAT-IAT(Demand Aeration