California Code of Regulations › Title 14 - Natural Resources › Division 7 - Department of Resources Recycling and Recovery › Chapter 9 - Planning Guidelines and Procedures for Preparing and Revising Countywide Integrated Waste Management Plans › Article 6.1 - Solid Waste Generation Studies › Appendix 1 - General Guidelines for Sampling when Performing a Quantitative Field Analysis for a Solid Waste Generation Study (CIWMB - November, 1990)

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
1. Sampling Solid Waste Generation, Diversion and Disposal
					 - Perform these tasks in the following order:
a. Identify the Populations.
In each jurisdiction, identify: the populations of (1)
					 residential units, commercial units, industrial sites, and other sites of solid
					 waste generation; (2) facilities and programs which recycle, compost, or source
					 reduce solid wastes; and (3) solid waste transfer stations, and permitted solid
					 waste transformation facilities and solid waste disposal sites.
For the purposes of these guidelines, a population is the
					 aggregate from which a sample is chosen, and refers to the aggregate number of
					 solid waste generators, solid waste diversion facilities and programs, or solid
					 waste transfer, transformation and disposal facilities identified by the
					 jurisdiction.
b. Stratify the Populations (Optional Step).
Stratify each identified population into distinct
					 subpopulations. The jurisdiction shall select the subpopulations. For example,
					 to stratify the population for a solid waste diversion characterization, the
					 jurisdiction could stratify the population of recycling facilities into the
					 following subpopulations: drop-off centers, buy-back centers, and thrift shops.
					 If the number of units in the subpopulation is small, the jurisdiction may
					 choose not to stratify the population, and instead choose a sample from the
					 population as a whole.
c. Random Sampling.
Assign a unique number to each identified unit of a
					 population or subpopulation. Using a random numbers table or any other unbiased
					 sampling method, choose the units to be sampled in the population or
					 subpopulation, for each season identified by a jurisdiction. State the type(s)
					 of unbiased sampling methods used in the solid waste generation study, when the
					 study is submitted to the Board as a part of the SRR Element.
2. Sampling and Variability Determination: In order to
					 determine the minimum number of samples to be taken from a population or
					 subpopulation, a jurisdiction may use one of the following two methods:
(a) Klee and Carruth Method.
Perform these tasks as follows:
(i) Sample, according to the requirements of sections
					 18722,
					 18724 and
					 18726 of this article, all of the
					 solid waste generated, all of the solid waste diverted from disposal by
					 recycling, composting or source reduction activities, and all of the solid
					 waste transformed and disposed, for each identified population or
					 subpopulation.
(ii) To determine the number of samples required for a
					 statistically representative sampling from each population or subpopulation,
					 the jurisdiction shall use the formula for normal approximation which is found
					 in: A.J. Klee and D. Carruth, "Sample Weights in Solid Waste Composition
					 Studies," American Society of Civil Engineers Journal of the Sanitary
					 Engineering Division, volume 96(SA4), pages 945-954, August 1970, which is
					 incorporated by reference. A 90% confidence interval shall be used in this
					 formula.
This formula is:
Click
					 here to view image
A 90% confidence level shall be used in this formula. Thus
					 at 90% confidence level, z = 1.645 and s = 0.1632, where z is the normal
					 standard deviate (one-tailed) for the confidence level desired and s is the
					 estimated standard deviation of the sample, transformed (arcsin) basis. A
					 jurisdiction shall use these values for z and s in computing the minimum number
					 of samples.
A jurisdiction shall select the confidence interval and
					 confidence width to be used in computing the minimum number of samples, i.e.,
					 the jurisdiction shall determine the [DELTA](small delta) value to use in the
					 formula.
In order to determine [DELTA], a jurisdiction shall
					 estimate its percent waste composition (X) by use of existing published data
					 (waste category, and waste type if available) about the jurisdiction. and/or
					 published data on percent waste composition from other jurisdictions. The
					 source of the value of X used in the solid waste generation study shall be
					 stated in the solid waste generation study.
Next, a jurisdiction shall select a level of precision or
					 sensitivity ([DELTA]) (large delta) (e.g., 1%, 2%, 3%) concomitant with its
					 need for a given level of precision. with its population, and with the funds it
					 has available for the solid waste generation study, as determined by the
					 jurisdiction.
The waste category occurring in the highest percent in the
					 selected waste stream shall be selected as the waste category for determining X
					 and computing [DELTA].
(iii) All solid waste generation studies prepared using the
					 Klee and Carruth Method for the purposes of meeting the requirements of the
					 Integrated Waste Management Act of 1989, as amended, and otherwise approved by
					 the Board, shall be considered to meet the requirements of this article.
b. American Society of Testing Materials (ASTM)
					 Method.
(i) Sample, according to the requirements of sections
					 18722,
					 18724 and
					 18726 of this article, all of the
					 solid waste generated, all of the solid waste diverted from disposal by
					 recycling, composting or source reduction activities, and all of the solid
					 waste transformed and disposed, for each identified population or subpopulation
					 in the jurisdiction.
(ii) A jurisdiction shall use section
					 9 and Table D of Draft No. 4 of
					 the proposed ASTM "Method for Determination of the Composition of Unprocessed
					 Municipal Solid Waste," dated January 24, 1990, which is incorporated by
					 reference. A jurisdiction may also use the values for s and x in Table C of
					 this method, or may use values for s and x found in published solid waste
					 characterization studies which were conducted in California subsequent to 1984.
					 Other sections of this Method may be used with section
					 9 and Table D. Once a final
					 version of this Method is adopted by ASTM, that Method shall become the
					 approved method for compliance with this article.
All solid waste generation studies prepared using the Draft
					 ASTM Method for the purposes of meeting the requirements of the Integrated
					 Waste Management Act of 1989, as amended, and otherwise approved by the Board,
					 shall be considered to meet the requirements of this article.
3. Sort and Identify.
Sort and identify the solid wastes from each population
					 and/or subpopulation, using the sources of waste generation listed in section
					 18722(i) of this
					 article, and the waste categories and waste types listed in section
					 18722(j) of this
					 article.
4. Assignment of Waste Category and Waste Type.
Assign each identified solid waste material to one of the
					 waste categories and waste types listed in sections
					 18722(j) of this
					 article, or to any additional waste types which a jurisdiction chooses to add
					 to the list of waste types in section (j) of this article.
5. Volume or Weight Measurement.
Measure the volume or weight of each solid waste material
					 that has been identified.
6. Tabulate and Analyze Data - Perform these tasks in the
					 following order.
Tabulate and analyze all data compiled about the waste
					 categories and waste types. As a part of the analysis, a jurisdiction shall
					 compute (a) and (b) as follows:
a. Determination of Mean and Variability.
Compute the sample mean (x[BAR]) for volume or weight for
					 each waste category and waste type identified.
Note, x[BAR] = [SUMMATION]xi /n,
					 where xi is a sample weight or volume and n is the total
					 number of samples taken in the population or subpopulation sampled.
Next, compute the variance (s2;
					 i.e., where s2 =
					 [SUMMATION](xi -
					 x[BAR])2/n-1) and the standard deviation of the
					 mean(s), for volume or weight measurement for each population and
					 subpopulation, using the following formula:
Click
					 here to view image
b. Set Confidence Levels for Sample Mean.
Set a 90% confidence level around the sample mean (x[BAR]),
					 for each waste category and waste type identified.
Use the formula:
Click
					 here to view image
where tn-1 is the t value taken from
					 the Student's t test values in Table 1, and where (n-1) is the degrees of
					 freedom for the Student's t test for a 90% confidence level.
Note: This formula is used to establish a confidence
					 interval for a population mean when the population variance is unknown. This
					 formula is found in: M. Woodward and L.M.A. Francis, 1988, Statistics for
					 Health Management and Research, section
					 7.4.3, pgs. 161-162, London:
					 Edward Arnold Publishers, which is incorporated by reference.
7. Data Analysis Adjustment.
The data analysis conducted in steps 1 through 6 may be
					 adjusted to include waste categories and waste types which:
(a) are known, by current written records held by the solid
					 waste recycling, composting, source reduction, transformation or disposal
					 facilities, to be disposed or diverted in a jurisdiction or in permitted solid
					 waste facilities used by a jurisdiction, and
(b) may otherwise have been overlooked in the random
					 sampling procedure.
TABLE 1
Student's t
								Values*
Number of
								Samples (n)
Degrees of
								Freedom (n-1)
90%
								Confidence Level
2
1
6.314
3
2
2.920
4
3
2.353
5
4
2.132
6
5
2.015
7
6
1.943
8
7
1.895
9
8
1.860
10
9
1.833
11
10
1.812
12
11
1.796
13
12
1.782
14
13
1.771
15
14
1.761
16
15
1.753
17
16
1.746
18
17
1.740
19
18
1.734
20
19
1.729
21
20
1.725
22
21
1.721
23
22
1.717
24
23
1.714
25
24
1.711
26
25
1.708
27
26
1.706
28
27
1.703
29
28
1.701
30
29
1.699
31
30
1.697
36
35
1.690
41
40
1.684
46
45
1.679
51
50
1.676
61
60
1.671
71
70
1.667
81
80
1.664
91
90
1.662
101
100
1.660
121
120
1.658
141
140
1.656
161
160
1.654
189
188
1.653
210
200
1.653
oo
oo
1.645
__________
* Source: George Savage, Draft ASTM Method, ASTM
					 Designation DXXXX-XX, Table D, January, 1990, Philadelphia, PA: American
					 Society of Testing Materials.
1. New
					 Appendix 1 filed 3-19-90 as an emergency; operative 3-19-90 (Register 90, No.
					 14). A Certificate of Compliance must be transmitted to OAL within 120 days or
					 emergency language will be repealed on 7-17-90.
2. New section
					 refiled 7-6-90 as an emergency; operative 7-17-90 (Register 90, No. 37). A
					 Certificate of Compliance must be transmitted to OAL by 11-14-90 or emergency
					 language will be repealed by operation of law on the following
					 day.
3. Editorial correction of Certificate of Compliance due date
					 in HISTORY 2 (Register 91, No. 13).
4. Request for readoption of
					 7-6-90 emergency regulations approved by OAL 11-6-90 but never filed with
					 Secretary of State. Section repealed by operation of Government Code section
					 11346.1(e)
					 (Register 91, No. 13).
5. New section refiled 2-15-91 as an
					 emergency; operative 2-15-91 (Register 91, No. 13). A Certificate of Compliance
					 must be transmitted to OAL by 6-17-91 or emergency language will be repealed by
					 operation of law on the following day.
6. Certificate of Compliance
					 as to 2-15-91 order, including amendments and new TABLE 1 transmitted to OAL on
					 4-29-91 and filed 5-29-91 (Register 91, No. 37).
7. Editorial
					 correction of NOTE, HISTORY 6 and TABLE 1, including correct placement of NOTE
					 and HISTORY (Register 94, No. 37).
Note: Authority cited: Sections
						40502
						and
						41824,
						Public Resources Code. Reference: Sections
						41030,
						41031,
						41032,
						41033,
						41300,
						41330,
						41331,
						41332,
						41333,
						41780
						and
						41781,
						Public Resources Code.