Page 1 of 1: psm -sand filters

clrsky · Credits: 9708 My Scrapbook

most important layer of a slow sand silter is
a.vital layer
b.sand bed
c.filter system
d.raw water

drada · Credits: 45712 My Scrapbook My Reading List 2 Books

vital layer ,

drada · Credits: 45712 My Scrapbook My Reading List 2 Books

Slow sand filtration relies on both physical and biological activity in controlling plant pathogens.
In a slow sand filter, the filter bed is constructed of a medium with high surface area which can be colonized by suppressive micro-organisms. This fine media also presents a physical barrier to the passage of spores of plant pathogens. Bacteria, such as representatives of the genus Pseudomonas and Trichoderma have been demonstrated as biological control agents effectively controlling plant pathogens in hydroponics systems. In a SSF, plant pathogens recirculating in the irrigation water are captured in the filter media, and at slow rates of water filtration (100-200 l/hr/m2 surface area of filter), are acted upon by the antagonistic micro organisms that colonized the filter bed.
The efficiency of SSF depends on the particle size distribution of the sand, the ratio of surface area of the filter to depth and the flow rate of water through the filter. The finest grade sand fractions and granulated rockwool have been shown to be most efficient in controlling diseases such as Phytophthora, Pythium and Fusarium oxysporum, the most widespread nursery diseases

drada · Credits: 45712 My Scrapbook My Reading List 2 Books

confused .sand bed / vital layer

clrsky · Credits: 9708 My Scrapbook

me too so only posted ie here

devirante · Credits: 2681 My Scrapbook

i'm quoting from park pg 526

1. vital layer is the "heart" of slow sand filter

2. when the filter is newly laid, it merely acts as a MECHANICAL STRAINER, but when vital layer is developed filter removes organic matter, holds back bacteria and yields bacteria free water

3. until the vital layer is fully formed, the first few days filterate is usually run to waste.

UNITHINM · Credits: 140 My Scrapbook

AM SURE ITS VITAL LAYER...

partha_aipg · Credits: 13088 My Scrapbook

yes no doubt abt it -vital layer.

partha

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