Current through Register Vol. 6, March 22, 2024
(1) For operators
certified prior to January 1, 2016, all water supply systems and wastewater
systems are classified according to population served or type of treatment as
shown below:
(a) Water distribution systems:
(i) Class 1--serving more than 20,000
people;
(ii) Class 2--serving 2,500
to 20,000 people;
(iii) Class
3--serving 500 to 2,500 people;
(iv) Class 4--serving 100 to 500
people;
(v) Class 5--serving fewer
than 100 people.
(b)
Water treatment systems:
(i) Class
1--treatment for surface water utilizing chemical coagulation, filtration, and
disinfection;
(ii) Class
2--treatment for surface water not utilizing chemical coagulation;
(iii) Class 3--well water supply serving
greater than 2,500 people, with or without disinfection;
(iv) Class 4--well water supply serving 100
to 2,500 people, with or without disinfection;
(v) Class 5--well water supply serving fewer
than 100 people, with or without disinfection.
(c) Wastewater treatment systems:
(i) Class 1--secondary and advanced
(tertiary) treatment provided by conventional activated sludge plants,
biological nutrient removal plants, ammonia conversion processes, or other
tertiary processes such as effluent filtration and membrane bioreactor
systems;
(ii) Class 2--secondary
treatment provided by extended aeration activated sludge plants such as
oxidation ditches and package plants, fixed-growth trickling filter and
bio-disc plants, or sequencing batch reactors;
(iii) Class 3--secondary treatment provided
by aerated lagoons;
(iv) Class
4--lagoons not utilizing artificial aeration.
(d) Industrial wastewater treatment systems:
(i) Class 1--physical-chemical or biological
treatment facility treating more than 1.0 mgd, including, but not limited to,
the following:
(A) air flotation;
(B) air stripping;
(C) reverse osmosis;
(D) electrochemical treatment;
(E) activated sludge;
(F) anaerobic digestion;
(G) aerobic digestion;
(H) nutrient removal systems;
(I) tertiary treatment; or
(J) chemical clarification;
(ii) Class 2--biological treatment
facilities treating 1.0 mgd or less, including, but not limited to, the
following:
(A) clarification;
(B) filtration;
(C) constructed wetlands;
(D) carbon adsorption;
(E) ion exchange;
(F) disinfection;
(G) trickling filters;
(H) bio-disc systems;
(I) sequencing batch reactors;
(J) biological sand filters;
(K) membrane filtration; or
(L) advanced on-site treatment and disposal
systems described under certification class (e)(ii) requirements;
(iii) Class 3--industrial
treatment facilities, including, but not limited to, the following:
(A) oil-water separation;
(B) grinding or communitors;
(C) land surface disposal;
(D) neutralization (pH adjustment);
(E) aerated lagoons;
(F) on-site septic tank treatment systems
with pressure dosed drainfields;
(G) siphon dosed drainfields; or
(H) elevated sand mounds;
(iv) Class 4--industrial treatment
facilities, including, but not limited to, the following:
(A) detention ponds;
(B) sedimentation ponds;
(C) stabilization ponds;
(D) lagoons without mechanical mixing or
aeration;
(E) septic systems
treating the discharge from drinking water treatment systems; or
(F) on-site treatment using standard septic
tanks and gravity drainfields.
(e) On-site systems:
(i) No class 1;
(ii) Class 2--package biological wastewater
treatment systems, which are public sewage systems and are regulated with a
MGWPCS discharge permit, including, but not limited to, the following:
(A) conventional activated sludge;
(B) sequencing batch reactor;
(C) fixed film; and
(D) extended aeration activated sludge
systems;
(iii) Class
3--treatment systems, which are public sewage systems and are regulated with a
MGWPCS discharge permit, including, but not limited to, the following:
(A) recirculating media trickling
filters;
(B) intermittent sand
filters;
(C) recirculating sand
filters;
(D) aerobic wastewater
treatment units;
(E) chemical
nutrient reduction systems;
(F)
alternate advanced treatment systems; and
(G) experimental systems;
(iv) Class 4--treatment with soil
absorption systems, which are public sewage systems and are regulated with a
MGWPCS discharge permit, including, but not limited to:
(A) standard absorption trenches;
(B) shallow capped absorption
trenches;
(C) deep absorption
trenches;
(D) sand-lined absorption
trenches;
(E) gravelless trenches
and other absorption methods;
(F)
elevated sand mounds;
(G)
evapotranspiration absorption and evapotranspiration systems;
(H) subsurface drip;
(I) gray water irrigation systems;
(J) absorption beds; and
(K) experimental systems.
(2) For
operators certified on or after January 1, 2016, all water supply systems and
wastewater systems are classified according to population served or type of
treatment as shown below:
(a) Water
distribution systems:
(i) Class 1--serving
more than 15,000 people;
(ii) Class
2--serving 1,501 to 15,000 people;
(iii) Class 3--serving 500 to 1,500
people;
(iv) Class 4--serving fewer
than 500 people.
(b)
Water treatment systems:
(i) Class
1--treatment for surface water utilizing chemical coagulation, filtration, and
disinfection;
(ii) Class
2--treatment for surface water not utilizing chemical coagulation;
(iii) Class 3--ground water supply serving at
least 500 people with or without disinfection;
(iv) Class 4--ground water supply serving
fewer than 500 people with or without disinfection.
(c) Wastewater treatment systems:
(i) Class 1--secondary and advanced
(tertiary) treatment provided by:
(A)
conventional activated sludge plants;
(B) biological nutrient removal
plants;
(C) ammonia conversion
processes;
(D) extended aeration
activated sludge plants, such as oxidation ditches and package plants,
fixed-growth trickling filter, and bio-disc plants;
(E) sequencing batch reactors; and
(F) other tertiary processes, such as
effluent filtration and membrane bioreactor systems;
(ii) Class 2--No class 2;
(iii) Class 3--secondary treatment provided
by aerated lagoons or lagoons not utilizing artificial aeration;
(iv) Class 4--No class 4.
(d) Industrial wastewater
treatment systems:
(i) Class
1--physical-chemical or biological treatment facility treating more than 1.0
mgd, including, but not limited to, the following:
(A) air flotation;
(B) air stripping;
(C) reverse osmosis;
(D) electrochemical treatment;
(E) activated sludge;
(F) anaerobic digestion;
(G) aerobic digestion;
(H) nutrient removal systems;
(I) tertiary treatment; or
(J) chemical clarification;
(ii) Class 2--biological treatment
facilities treating 1.0 mgd or less, including, but not limited to, the
following:
(A) clarification;
(B) filtration;
(C) constructed wetlands;
(D) carbon adsorption;
(E) ion exchange;
(F) disinfection;
(G) trickling filters;
(H) bio-disc systems;
(I) sequencing batch reactors;
(J) biological sand filters;
(K) membrane filtration; or
(L) advanced on-site treatment and disposal
systems described under certification class (e)(ii) requirements;
(iii) Class 3--industrial
treatment facilities, including, but not limited to, the following:
(A) oil-water separation;
(B) grinding or communitors;
(C) land surface disposal;
(D) neutralization (pH adjustment);
(E) aerated lagoons;
(F) on-site septic tank treatment systems
with pressure dosed drainfields;
(G) siphon dosed drainfields; or
(H) elevated sand mounds;
(iv) Class 4--industrial treatment
facilities, including, but not limited to, the following:
(A) detention ponds;
(B) sedimentation ponds;
(C) stabilization ponds;
(D) lagoons without mechanical mixing or
aeration;
(E) septic systems
treating the discharge from drinking water treatment systems; or
(F) on-site treatment using standard septic
tanks and gravity drainfields.
(e) On-site systems:
(i) No class 1;
(ii) Class 2--package biological wastewater
treatment systems, which are public sewage systems and are regulated with a
MGWPCS discharge permit, including, but not limited to, the following:
(A) conventional activated sludge;
(B) sequencing batch reactor;
(C) fixed film; and
(D) extended aeration activated sludge
systems;
(iii) Class
3--treatment systems, which are public sewage systems and are regulated with a
MGWPCS discharge permit, including, but not limited to, the following:
(A) recirculating media trickling
filters;
(B) intermittent sand
filters;
(C) recirculating sand
filters;
(D) aerobic wastewater
treatment units;
(E) chemical
nutrient reduction systems;
(F)
alternate advanced treatment systems; and
(G) experimental systems;
(iv) Class 4--treatment with soil
absorption systems, which are public sewage systems and are regulated with a
MGWPCS discharge permit, including, but not limited to:
(A) standard absorption trenches;
(B) shallow capped absorption
trenches;
(C) deep absorption
trenches;
(D) sand-lined absorption
trenches;
(E) gravelless trenches
and other absorption methods;
(F)
elevated sand mounds;
(G)
evapotranspiration absorption and evapotranspiration systems;
(H) subsurface drip;
(I) gray water irrigation systems;
(J) absorption beds; and
(K) experimental systems.
(3) In order
to calculate the class of a particular water supply system pursuant to (1)(a)
or (b) when an accurate population census is not available, the population
served may be determined by multiplying the number of service connections by
2.5.
(4) For the purposes of this
subchapter, a system classified with a lower number is considered more complex
than a system classified with a higher number, i.e., a Class 1 system is more
complex than a Class 2 system.
AUTH:
37-42-202, MCA; IMP:
37-42-104,
37-42-304,
37-42-306,
MCA