ISO 23139:2023 空気およびその他のガスを処理するための生物学的装置 — 廃水処理プラントにおける脱臭の要件と適用ガイダンス | ページ 6

3.1

wastewater treatment plant

WWTP

plant that purifies wastewater with physical, chemical, biological methods or a combination of those to make the discharge conform to the requirements of discharge standards or the need for environmental protection

3.2

odorant

substance which has the potential to get volatilized and stimulate a human olfactory system so that an odour is perceived

Note 1 to entry: Typical odorants in WWTPs include sulfur-containing compounds (hydrogen sulfide, organic sulfides), nitrogen-containing compounds (ammonia, amines) and volatile organic compounds (VOCs).

3.3

odour gas

waste gas containing odorants emitted from industrial, civil or domestic processes

3.4

odour source in WWTPs

structure or equipment emitting odour gases in a wastewater treatment plant

Note 1 to entry: In WWTPs, the primary odour source includes the wastewater pre-treatment units, anaerobic treatment units and waste sludge treatment units. Sulfides including hydrogen sulfide are the typical odorants from the raw wastewater. Sulfides, ammonia and VOCs are the typical odorants from the waste sludge. The emission increases where there is turbulence or disturb in the wastewater or waste sludge.

3.5

odour concentration

quantitative indicator of odour intensity through tests with olfactory organs

Note 1 to entry: The value of odour concentration is the diluted multiples of the odour gas samples to the detection threshold value of panellists using clean air.

Note 2 to entry: The odour concentration of the raw odour gas varies greatly from case to case and is affected by odorants emission rate and configuration of collection system. Odour concentration can be measured according to different methodologies such as ASTM D 1391, EN 13725 or GB/T 14675-93.

Note 3 to entry: The odour concentrations measured by different methods cannot be compared directly.

3.6

bioreactor for deodorization

biological reactors used to treat odour gases collected from different odour sources to minimize the emission of odorants

Note 1 to entry: Biological reactors for waste gas treatment are typically biofilm reactors with microbial colonies immobilized on the surface of packing media, such as a biofilter or a trickling biofilter. The other type of biological reactors are suspended-growth reactors with the microbial populations suspended in a liquid medium, such as a bioscrubber. For WWTPs applications, biofilters and trickling biofilters are much more applied than bioscrubbers.

3.7

biofilter

bioreactor treating waste gas with the aid of biofilm attached to the packing media which moisture is maintained by a prepositive humidifier or intermittent water feeding to the filter bed

Note 1 to entry: The typical packing media employed are organic or/and inert materials randomly packed in the filter beds.

3.8

trickling biofilter

biotrickling filter

bioreactor treating waste gas with free moving liquid layers on the surface of inert packing media to supply nutrients, take away metabolites or control pH for the biofilm attached to the packing media

Note 1 to entry: The typical packing media employed are inert materials randomly or structured packed in the filter beds.

Note 2 to entry: External nutrients addition is required when the packing media cannot offer enough nutrients for the growth of microorganism.

3.9

bioscrubber

absorber transferring contaminants from waste gas to liquid absorbent, and removing the dissolved contaminants by suspended-growth microorganisms in a supplementary space

Note 1 to entry: The built-in device of the scrubbing unit can be a bulk or structured packing or a construction with plates or a rotating disk.

Note 2 to entry: External nutrients addition is usually required.

Note 3 to entry: Pre-humidification is not required.

3.10

filter bed

bed including the packing media and the microorganisms on the surface of packing media

Note 1 to entry: The typical packing media employed are natural or/and artificial materials randomly or structured packed.

Note 2 to entry: The typical microorganisms are bacteria or/and fungi in form of biofilm on the surface of the packing media or free cells in the liquid.

Note 3 to entry: Odour gas passes through the filter bed and gets purified by mass transfer and biological degradation of odorants.

3.11

superficial velocity

volumetric odour gas flow rate divided by the free cross-section area of the bioreactor column, with unit in m/s or m/h

3.12

empty bed residence time

EBRT

total volume of the filter bed divided by the odour gas flow rate

Note 1 to entry: Unit is in s.

3.13

odorant removal efficiency

E

ratio of odorant concentration reduction and inlet odorant concentration

Note 1 to entry: Removal efficiency is also referred to as elimination efficiency.

3.14

odorant removal rate

r

amount of odorants removed by a unit volume of packing material in a unit time

Note 1 to entry: Removal rate (r) is also referred to as elimination capacity (EC) or elimination rate (ER).

Note 2 to entry: It is generally used to evaluate the capacity of the reactors for odorant removal. It is very relevant and useful for the comparison of various bioreactors. It is important to note that E is dependent upon the inlet odorant concentration or EBRT of a bioreactor.

3.15

pressure drop

difference in static gas pressure between the inlet and outlet of the equipment

Note 1 to entry: The pressure drop of the bioreactor and odour gas collection duct will affect the energy consumption of the blower and its operational costs. The pressure drop of the bioreactor is mainly decided by the character of the filter bed and the superficial velocity.