pipepermcalc.pipe module

class pipepermcalc.pipe.Pipe(segment_list)

Bases: object

Pipe object class to make segments of the pipe and calculate the peak and mean concentration of a chemical in groundwater and soil.

segment_list

list of the pipe segment objects which make up the pipe

Type:

list

_conditions_set

Default False, True when the groundwater conditions have been set.

Type:

Boolean

_flow_rate_set

Default False, True when the flow rate has been set.

Type:

Boolean

_concentration_groundwater_set

Default False, True when the flow rate has been set.

Type:

Boolean

_is_validated

Default False, True when the flow rate has been set.

Type:

Boolean

total_volume

Total volume of the pipe, summed from the pipe segments, m3

Type:

float

total_length'

Total length of the pipe, summed from the pipe segments, m

Type:

float

flow_rate

Flow rate through pipe, m3/day.

Type:

float

CAS_number

CAS is a unique identification number assigned by the Chemical Abstracts Service (CAS)

Type:

string

chemical_name_EN

Name of the chemical in English

Type:

string

chemical_name_NL

Name of the chemical in Dutch

Type:

string

molecular_weight

Mass of one mole of a given chemical, g/mol

Type:

float

solubility

solubility of given chemical in water, g/m3

Type:

float

log_octanol_water_partitioning_coefficient

Partition coefficient for the two-phase system consisting of n-octanol and water, Log Kow, [-]

Type:

float,

log_distribution_coefficient

Ratio of the amount of chemical adsorbed onto soil per amount of water, m3/g

Type:

float

chemical_group

Grouping of chemicals (expert opinion) with similar properties for permeation: Group 1: PAK, MAK, ClArom, ClAlk, Arom, Alk, Group 2: PCB, Group 3: overig, onbekend, O2, Cl, BDE. See KWR 2016.056

Type:

string

chemical_group_number

Integer corresponding to the chemical group

Type:

integer

molecular_volume

Volume occupied by one mole of the substance at a given temperature and pressure, cm3/mol.

Type:

float

Drinking_water_norm

Concentration allowable in the Dutch Drinking water decree, g/m3.

Type:

float

_Kd_known

True when a distribution coefficient (Kd) for the chemical is known. Kd is needed to convert from soil to groundwater concentration.

Type:

Boolean

concentration_groundwater

Concentration of the given chemical in groundwater, g/m3.

Type:

float

tolerance

The degree of acceptable error in the accuracy of the calculation, calculated as the difference between the calculated and actual drinking water concentration, default value of 0.01 (1%), [-].

Type:

float

max_iterations

Maximum number of iterations allowed in the optimization scheme.

Type:

int

temperature_groundwater

Temperature of the groundwater, degrees Celcius.

Type:

float

stagnation_time

Time in seconds which water in pipe is stagnant, unit of seconds. The stagnation factor is only valid for a stagnation time of 8 hours (28800 seconds), therefore using another other stagnation time is not advised.

Type:

float

concentration_soil

Concentration of the given chemical in soil, mg/kg.

Type:

float

scale_factor_upper_limit

Scale factor used to set the upper limit of the bounds for calculating the mean concentration of drinking water or groundwater. Upper limit taken as the concentration of groundwater (solving for drinking water concentration) or solubility (solving for groundwater concentration) multiplied by the scale factor. Default value of 0.999

Type:

float

scale_factor_lower_limit

Scale factor used to set the upper limit of the bounds for calculating the mean concentration of drinking water or groundwater. Lower limit taken as the concentration of groundwater (solving for drinking water concentration) or solubility (solving for groundwater concentration) multiplied by the scale factor. Default value of 0.0001.

Type:

float

ASSESSMENT_FACTOR_GROUNDWATER

Factor used to correct calculations for observations in actual pipe permeation. Permeation of PE house connections in groundwater = 3, other pipe materials = 1. See section 7.2 in KWR 2016.056

Type:

float

ASSESSMENT_FACTOR_SOIL

Factor used to correct calculations for observations in actual pipe permeation. All pipe materials = 1.

Type:

float

Note

All parameters are in SI units: m, m2, g/m3 (equivalent to mg/L), seconds. Except for the flow rate, which is given in m3/day.

ASSESSMENT_FACTOR_GROUNDWATER = 3
ASSESSMENT_FACTOR_SOIL = 1
MAX_ITERATIONS_DEFAULT = 1000
SCALE_FACTOR_LOWER_LIMIT = 0.0001
SCALE_FACTOR_UPPER_LIMIT = 0.999
STAGNATION_TIME_DEFAULT = 28800
TEMPERATURE_GROUNDWATER_DEFAULT = 12
TOLERANCE_DEFAULT = 0.01
calculate_mean_allowable_gw_concentration(tolerance=0.01, max_iterations=1000, debug=False)

Calculates the mean 24 hour concentration in groundwater which would not result in a drinking water concentration exceeding the drinking water norm. If the distribution coefficient is known the soil concentration is also calculated.

Parameters:

  • tolerance (float) – The degree of acceptable error in the accuracy of the calculation, calculated as the difference between the calculated and actual drinking water concentration, default value of 0.01 (1%), [-].

  • max_iterations (int) – Maximum number of iterations allowed in the optimization scheme

  • debug (Boolean) – If True, return the groundwater concentration, goodness_fit and lower and upper limits every iteration.

Returns:

concentration_mean_allowable_groundwater – Mean concentration in groundwater which would would not result in a mean daily (24 hours) concentration in drinking water exceeding the drinking water norm, g/m3.

Return type:

float

calculate_mean_dw_concentration(tolerance=0.01, max_iterations=1000, debug=False)

Calculates the mean concentration in drinking water for a 24 hour period given a groundwater concentration.

Parameters:

  • tolerance (float) – The degree of acceptable error in the accuracy of the calculation, calculated as the difference between the calculated and actual drinking water concentration, default value of 0.01 (1%), [-].

  • max_iterations (int) – Maximum number of iterations allowed in the optimization scheme

Returns:

mean_concentration_pipe_drinking_water – Calculates the mean concentration in drinking water for a 24 hour period given a groundwater concentration.

Return type:

float

calculate_peak_allowable_gw_concentration(tolerance=0.01, max_iterations=1000, debug=False)

Calculates the peak (maximum) concentration in groundwater water for a given a stagnation period that would not result in a peak concentration in drinking water exceeding the drinking water norm for each pipe segment. Stagnation period default of 8 hours. If the distribution coefficient is known the soil concentration is also calculated.

Parameters:

  • tolerance (float) – The degree of acceptable error in the accuracy of the calculation, calculated as the difference between the calculated and actual drinking water concentration, default value of 0.01 (1%), [-].

  • max_iterations (int) – Maximum number of iterations allowed in the optimization scheme

  • debug (Boolean) – If True, return the groundwater concentration, goodness_fit and lower and upper limits every iteration.

Returns:

concentration_peak_allowable_groundwater – Concentration in groundwater which, after a stagnation period, would not result in a peak concentration in drinking water exceeding the drinking water norm, g/m3.

Return type:

float

calculate_peak_dw_concentration(tolerance=0.01, max_iterations=1000, debug=False)

Calculates the peak (maximum) concentration in drinking water for a given a stagnation period given a groundwater concentration. Stagnation period default of 8 hours.

Parameters:

  • tolerance (float) – The degree of acceptable error in the accuracy of the calculation, calculated as the difference between the calculated and actual drinking water concentration, default value of 0.01 (1%), [-].

  • max_iterations (int) – Maximum number of iterations allowed in the optimization scheme

Returns:

peak_concentration_pipe_drinking_water – Calculates the peak (maximum) concentration in drinking water for a given a stagnation period given a groundwater concentration.

Return type:

float

parameter_validation_dictionary = {'chemical_name': {'value_dtype': [<class 'str'>]}, 'concentration_drinking_water': {'min_value': 0, 'value_dtype': [<class 'float'>, <class 'int'>]}, 'concentration_groundwater': {'min_value': 0, 'value_dtype': [<class 'float'>, <class 'int'>]}, 'concentration_soil': {'min_value': 0, 'value_dtype': [<class 'float'>, <class 'int'>]}, 'diffusion_path_length': {'min_value': 0, 'value_dtype': [<class 'float'>, <class 'int'>]}, 'flow_rate': {'min_value': 0, 'value_dtype': [<class 'float'>, <class 'int'>]}, 'inner_diameter': {'min_value': 0, 'value_dtype': [<class 'float'>, <class 'int'>]}, 'language': {'str_options': ['NL', 'EN'], 'value_dtype': [<class 'str'>]}, 'length': {'min_value': 0, 'value_dtype': [<class 'float'>, <class 'int'>]}, 'material': {'str_options': ['PE40', 'PE80', 'SBR', 'EPDM', 'PVC'], 'value_dtype': [<class 'str'>]}, 'name': {'value_dtype': [<class 'str'>]}, 'permeation_direction': {'str_options': ['perpendicular', 'parallel'], 'value_dtype': [<class 'str'>]}, 'stagnation_time': {'min_value': 0, 'value_dtype': [<class 'float'>, <class 'int'>]}, 'temperature_groundwater': {'min_value': 0, 'value_dtype': [<class 'float'>, <class 'int'>]}, 'wall_thickness': {'min_value': 0, 'value_dtype': [<class 'float'>, <class 'int'>]}}
ppc_database = CAS_number  ... Drinking_water_norm 0       66-25-1  ...                 NaN 1       71-55-6  ...              0.0010 2       79-34-5  ...                 NaN 3       79-00-5  ...              0.0010 4         75342  ...              0.0010 ..          ...  ...                 ... 422    108-88-3  ...              0.0010 423         NaN  ...              0.0001 424  1979-01-06  ...              0.0100 425         NaN  ...                 NaN 436  1975-01-04  ...              0.0001  [299 rows x 11 columns]
set_conditions(chemical_name, concentration_groundwater=None, concentration_soil=None, flow_rate=None, concentration_drinking_water=None, temperature_groundwater=12, stagnation_time=28800, suppress_print=False, suppress_warning=False, language='NL')

Specifies the chemical of interest, concentration and temperature in the groundwater and returns the parameters as attributes of the class. If the concentration of groundwater is given, or the soil concentration and Kd are known, the diffusion and permeation parameters are calculated for the pipe segment(s).

Parameters:

  • chemical_name (string) – Name of the chemical for which to calculate the permeation

  • concentration_groundwater (float) – Concentration of the given chemical in groundwater, g/m3

  • concentration_soil (float) – Concentration of the given chemical in soil, mg/kg.

  • flow_rate (float) – Flow rate through pipe, m3/day.

  • concentration_drinking_water (float) – Concentration of given chemical in drinking water pipe, g/m3. If no value given, concentration is assigned the drinking water norm value.

  • temperature_groundwater (float) – Temperature of the groundwater, degrees Celcius

  • stagnation_time (float) – Time in seconds which water in pipe is stagnant, unit of seconds. The stagnation factor is only valid for a stagnation time of 8 hours (28800 seconds), therefore using another other stagnation time is not advised.

  • suppress_print (Boolean) – Suppress printing the chemical name and matching name, e.g. in loop calculations

  • language (str) – Language fo the chemical name to search for, default is Dutch (‘NL’), English (‘EN’) also possible

validate_input_parameters()

Check that the input parameters are valid values and types for the Pipe and Segment objects

view_database_chemical_names(language='NL')

Function to view a list of the possible chemical names from the database.

Parameters:

language (str) – Language fo the chemical name to search for, default is Dutch (‘NL’), English (‘EN’) also possible