Water Treatment Plants - Horizontal Settling Tanks and Fast Filters

Contents

Contents

Introduction

1 Selection of process diagram of treatment facilities

1.1 Analysis of source river water

1.1.1 Determination of the efficiency of the treatment plant

1.2 Determination of total turbidity

1.3 Process Flow Chart Selection

2 Calculation of water treatment plant structures

2.2 Calculation of vertical mixer

2.3 Calculation of horizontal settling tanks

2.3.1 Calculation of sump dimensions

2.3.2 Calculation of clarified water collection system

2.3.3 Calculation of sludge removal system from sump

2.4 Calculation of the flocculation chamber

2.5 Calculation of fast filters

2.5.1 Determination of filter area

2.5.2 Calculation of the filter distribution system

2.5.3 Calculation of devices for collection and discharge of water during flushing

2.5.4 Calculation of the prefabricated channel

2.5.6 Selection of pumps for filter flushing

2.5.7 Determination of pipeline diameters

3 Calculation of sand economy

4 Calculation of reagent economy

4.1 Determination of volume of solution and service tank

4.2 Calculation of blowers

5 Calculation of flushing water treatment facilities

6 Sedimentation treatment facilities

7 Water water disinfection

7.1 Calculation of the laboratory unit for liquid chlorine dosing

8. Water fluorination

9. Plot plan and high-altitude diagram of the station

10. Sanitary Protection Zones

List of literature

Introduction

In this course design, water treatment facilities (PIC) are designed for the purification of natural water from a surface source (river), the quality of which does not meet the requirements of SanPiN 2.1.4.107401 .

The erected treatment facilities are located in the Saratov region. The capacity of treatment facilities is 68367.0 m3/day. The erected structures belong to the I category of reliability.

BOS design was carried out taking into account the requirements of SNiP 2.04.0284 "Water supply. External networks and structures. "

When designing BOC, clarifiers with suspended sludge and fast filters were adopted as the main structure. Water decontamination is performed by chlorination.

The layout of the main building, its cross section, high-rise scheme and the general plan of the water treatment plant have been developed.

Boundaries of I zone of sanitary protection zone of water treatment plant are defined and, in accordance with requirements [1], recommendations on its organization are given.

Wash Water Treatment Facilities

To reduce water consumption for the own needs of the treatment station, structures are arranged that allow you to clean and reuse the discharge water after washing the fast filters.

There is a sand head in which the suspension and averaging tanks are retained, after which water is pumped to the pipeline before the mixer.

From the treatment station, the washing water is pumped to the pipeline upstream of the treatment station mixer.

Sedimentation treatment facilities

The mixture of sedimentation of settling tanks, storage tanks of coagulant, RFV is supplied to the thickener, which is a vertical settling tank, in which the precipitate is mixed with a stirrer at a linear speed equal to 0.03 m/s. Thickening time is taken equal to 6 h according to [1], which is to be specified during operation.

Compacted sediment is directed to mechanical dewatering on press filters.

The dewatered sludge is stored outside the treatment plant.

Plot plan and high-altitude diagram of the station

When developing the water treatment plant plot plan, the main design requirements were taken into account:

1) compact mutual arrangement of separate water treatment facilities, auxiliary rooms and equipment;

2) minimum length of pipelines and pavements;

3) convenience of repair works, reliability and uninterrupted operation of the complex, possibility of systematic expansion with water consumption increase.

On the territory of the station - in the maximum security sanitary zone, in addition to the main structures, auxiliary rooms, clean water tanks, a boiler room, a laboratory, an administrative complex, garages, and parking lots are located. The administrative building is located next to the aisle.

Approaches and roads are carried out to all buildings, communications are brought. There are green spaces on the territory. The structures are located along the natural slope of the terrain, taking into account head losses in structures, connecting communications and measuring devices.

A bypass communication system is provided at the water treatment station, which provides the possibility of disconnecting individual structures, as well as water supply in case of an accident, bypassing the structures. [1]

Design water elevations for the facilities are determined by the recommended head losses in the treatment facilities and in the communications between them and accepted [1]:

- on mesh microfilters - 0.4 m;

- in the contact chamber - 0.3 m;

- from contact chamber to mixer - 0.2 m;

- in mixers - 0.5 m;

- from mixers to flocculation chambers - 0.4 m;

- in the flapping chamber - 0.4 m;

- in horizontal settling tank - 0.7 m;

- from horizontal settling tanks to fast filters - 0.5 m;

- in fast filters - 3.5 m;

- from fast filters to RChV - 1.0 m.

The elevation of the highest water level in clean water tanks is accepted 0.3 m above the ground elevation.

Sanitary protection areas

ZSO are organized in three belts: the first belt (of strict regime) includes the territory of the location of water intakes, the sites of all water supply facilities and the water supply channel.

The second and third zones (restriction zones) include an area designed to prevent water pollution from water sources.

The boundary of the first ZSO zone of water supply facilities is accepted at the distance:

- from walls of spare and regulating vessels, filters and contact clarifiers - not less than 30 m;

- from other rooms (settling tanks, reagent facilities, chlorine storage, pumping stations, etc.) - at least 15 m.

The territory of the first ZSO belt is planned to divert surface runoff beyond its limits, landscaped, fenced and provided with protection. The tracks to the structures have a solid coating.

It is not allowed: planting high-trunk trees, all types of construction that are not directly related to the operation, reconstruction and expansion of water supply facilities, including the laying of pipelines for various purposes, the placement of residential and household buildings, living people, the use of toxic chemicals and fertilizers.

The buildings are equipped with sewerage with waste water diversion to the nearest domestic or industrial sewerage system or to local treatment plants located outside the first zone of the ZSO, taking into account the sanitary regime in the territory of the second zone.

Within the boundaries of the second zone of the sanitary protection zone, it is prohibited to discharge industrial, agricultural, urban and storm wastewater in which the content of chemicals and microorganisms exceeds hygienic standards of water quality established by sanitary regulations. The boundaries of the second ZSO belt at the intersection of roads, hiking trails, etc., are indicated by pillars with special signs. [7]

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