Sludge dewatering.pptx

7/27/2019 Sludge dewatering.pptx

1/27

SLUDGE DEWATERING

NORZIHAN NABILAH BINTI ABU BAKARNOR FARHANA NABILA BINTI YUSOFFNUR SYAFIQAH BINTI ROSLEENOR AKHMA BINTI YAZID

SUZIELA BINTI ASMANZULINA BINTI YUSOF

PREPARED FOR:PUAN JURINA BINTI JAAFAR


2/27

What is Sludge Dewatering?

The physical process of removing the water contentsludge.

the final step for industrial wastewater treatment pand plants.


3/27

Why Dewater Sludge?

Most producers pay for sludge disposal by weight, andheavy. So if you remove as much water as possible, yodewatered sludge is lighter and thus costs less to disposludge and increases the number of recycling options a

reduces risk of outlet availability. The bottom line is th

effective Sludge dewatering can save you money. reduction of storage place and transportation costs


4/27

Methods of sludge dewaterin

Belt filter CentrifugeFra

filter

Vacuumfiltration

Dryingbed


5/27

What is the most effective solutio

Sludge Dewatering?

This is not easily answered without a comprehensive eof your specific needs including the final disposition ofsludge cake including whether you will be applying theland applications, landfill disposal, alternative fuels, fu

processing and so on. Analyzing each situation is critic

optimize the wastewater sludge aspect of your municiwastewater treatment processes.


6/27

CENTRIFUGE DECANTOR

use centrifugal force to accelerate solid-liquid seper centrifuge is a conical cylinder decantor that turns h

on its axis with a clarified water overflow

dewatered sludge being removed by an Archimedea


7/27


8/27

ADVANTAGES DISADVANTAGES

High capacity High capital cost

Low space requirement High maintenance costHigh speed of operationVibration phenomena

High level of technical expertise requiredpersonnel

Continuous dewatering in an enclosed unit Noize levels exceeding 85dB(A)

Unmanned operation High operational costHigh level of technical expertise requiredpersonnel

High power consumptionApprox. 4% higher DS than achieved than with abelt press

Operation -the dewatering process is not

Suitable for all sludge types (including oily/fattysludges)

High polyelectrolyte consumption


9/27

BELT FILTER PRESS

Belt filter presses are used to remove water from liquidwastewater residuals and produce a non-liquid materialto as cake.

A belt filter dewaters by applying pressure to the sludgesqueeze out the water

Sludge sandwiched between two tensioned porous beltpassed over and under rollers of various diameters

Increased pressure is created as the belt passes over roll

decrease in diameter


10/27

Divided into three zones

1. gravity zone

free draining water is drained by gravity through a porous belt

2. wedge zone

where the solids are prepared for pressure application

3. pressure zone where medium, then high pressure is applied to the conditione


11/27

Diagram of a belt filter

Sludge in the feed hopper is sandwiched between two filter cloths (shown green andis extracted initially by gravity, then by squeezing the cloth through rollers. Filtrate edrain, while solids are scraped off into a container.
http://en.wikipedia.org/wiki/File:BeltPress.svghttp://en.wikipedia.org/wiki/File:BeltPress.svg


12/27


13/27

Advantages Disadvantage

Maintenance is relatively simple and

can usually be completed by awastewater treatment plantmaintenance crew

Belt presses can be started and shutdown quickly compared to

centrifuges, which require up to anhour to build up speed

There is less noise associated withbelt presses

Odors may be a problem

Wastewater solids with hconcentrations of oil andresult in blinding the beltlower solids content cake

Wastewater solids must

and/or ground to minimisharp objects damaging


14/27

FRAME FILTER PRESS DEWATERI

Also called a filter press, the operating principle is filtrat

A filter press is composed of a series of hollow vertical ffilter cloths stretched on both sides.

These frames are hung next to each other and pressed t

with a hydraulic jack.

A filter chamber is formed between the plates.

Filter presses operate applying very high pressures to th

(from 5 to 15 bars and sometimes even more).


15/27


16/27

PLAN VIEW


17/27

FILTRATION CYCLE

Filling phase:At the start of the cycle, the conditioned sludge is injected in the filtration chambers by a high-pre

sludge fills each chamber and the water starts to seep out.


18/27

Filtration phase:Once all the chambers are filled, the sludge continues to be pumped in and the pressure increases bars. The filtrate flows into the channels placed in each frame and is evacuated in a main pipe. The sreduce when the pressure increases. Very often, two separate off-centre-screw pumps are used: a hpressure pump for the beginning of the cycle and a low flow/high pressure pump for the end.


19/27

Opening phase:Several parameters may be used to signal the end of the cycle (stopping the injection pump): maxfiltration time, filtrate volume. Once the press has stopped, the central core is purged of the liquidjack that presses the frames together is released. The chambers are opened sequentially and the ca skip or on to a conveyor.


20/27

Recently developed to obtain higher cake dryness than on regular Frame Filter Press. Every secoof a membrane that can be shaped by air or water pressure (7-10 bars). This extra pressure is apthe injection phase, once the cake is formed.

Filtration capacityThe production capacity of a filter press is somewhere between 1.5 and 10 kg of solid per m 2 ofFor every the filter press model the chamber volume and the filtering surface depend on the nuthe filter.

Membrane Filter Presses


21/27

FILTRATIONTIME

cake thickness

sludgeconcentration

specificresistance

compressibilitycoefficient.


22/27

VACUUM FILTRATION

Vacuum filters involve creating a vacuum to draw out wsolids.

The filter consists of a drum over which the filtering melaid.

The drum is set in a tank with one quarter submerged inor sludge.

Valves and pipes are arranged so that a vacuum is appliinner side of the filter medium as the drum rotates slowwater to be drawn from the sludge.

Once the drum has lifted the sludge into the atmospherlayer has been drawn to the top of the cake and the caksubsequently removed by a stationary knife blade.


23/27


24/27

Operating cost is higher

Independent of seasons and weather conditions

Dry solids enough to eliminate subsequent steps such as digestion or heattreatment before disposal, incineration, or usage

Need small area

Rated in pounds per hour dry solids filtered per area of filter surface.

Run as continuous process


25/27

DRYING BED

Traditional method. Commonly used in dry regions where land area is no

premium.

Generally used for dewatering of well digested slud

Attempts to air dry raw sludge usually result in odor


26/27


27/27

Advantages Disadvantages

No chemicals required High capital cost

Ease of operation Labour intensive Mechanical equipment required for

removal/handling Hard labour required

High dry solid % Weather sensitive; not effective in wet

No expert is need in order to operate the drying bedprocess

Possibility of odor

Documents

Sludge dewatering.pptx