1、NSF Protocol PI50 Bathroom Tissue Disposed into Septic Systems (1 993) NSF International fc I NSF International, an independent, not-for-profit organization, is dedicated to public health safety and protection of the environment by developing standards, by providing education and by providing superi
2、or third-party conformity assessment services while representing the interest of all stake ho Ide rs. This Protocol is subject to revision. Contact NSF to confirm this revision is current. Users of this Protocol may request clarifications and interpretations, or propose revisions by contacting: NSF
3、International Engineering & Research Services 789 Dixboro Road Ann Arbor, MI 48105 Phone: (734)769-8010 Telex: 75321 5 NSF INTL FAX: (734)769-O1 O9 E-mail: infa nsf,org Web: Copyright O 1993 NSF International Page i NSF PROTOCOL PI50 BATHROOM TISSUE DISPOSED INTO SEPTIC SYSTEMS (1993) Prepared by: N
4、SF International Engineering & Research Services 3475 Plymouth Road Ann Arbor, MI 48105 Copyright 8 1993 All Rights Reserved Copyright O 1993 NSF International Page 1 of 8 SECTION 1. INTRODUCTION 1 .o 1 .I 1.2 1.3 1.4 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 Scope: This protocol applies to bathroom tissu
5、e products intended for disposal to household septic systems. Purpose: Testing will determine the fate of bathroom tissue in a septic system and the effect of bathroom tissue on the treatment efficiency and effluent quality of a septic tank. The data obtained during the testing is used to determine
6、if the test products are acceptable for disposal into septic systems. Limitations: The use of the data and report generated from work completed under this protocol shall conform with the contract between the Company and NSF. NSF Protocol Review: A complete review of this protocol shall be conducted
7、at least every five years to keep requirements consistent with new research findings, technology, or regulatory changes. Reverification: After the initial product evaluation, NSF will periodically review product performance and characteristics, including audits and/or retesting. SECTION 2. DEFINITIO
8、NS Chelsea Wastewater Technology Site: NSF Field site located in Chelsea, Michigan used for performing full-scale septic system evaluations. Comminutor: A grinder or shredder that converts bulky solid wastes into smaller pieces. Company: Any public or private organization, group, individual, or othe
9、r entity contracting with NSF, or a subsidiary of division of such an entity. Effluent: Wastewater flowing out of a septic tank or other treatment process. Effluent Screen: A 1/8“ wire mesh configured to fit into the lower arm of a sample tee for collection of large solids passing through a septic t
10、ank. Household septic system: A waste disposal system consisting of a primary settling tank (septic tank) followed by a subsurface drainfield for treatment and disposal of liquid effluent from the septic tank. Influent: Wastewater flowing into a septic tank or other treatment process. NSF: NSF Inter
11、national, its staff, or other authorized representatives. NSF Protocol: A document which states a set of requirements for a product, Copyright O 1993 NSF International Page 2 of 8 2.9 2.1 o 2.1 1 2.1 2 2.1 3 3.0 3.1 3.2 3.3 3.4 3.5 system or service and the procedures for determining if a product, s
12、ystem or service conforms to the requirements. Protocol Certification: A certification authorized in writing by NSF International (NSF) for use on product packaging or in advertising that uses the NSF name and logo. pH: The negative logarithm of the hydrogen ion concentration in a solution. Scum: Th
13、e mass of matter that floats on the surface of a septic tank. Sludge: The settled solids retained in a septic tank. Total Suspended Solids (TSS): removed by standard filtering procedures in a laboratory, expressed as mg/L. Solids in wastewater which can be readily SECTION 3. REQUIREMENTS Product I d
14、entif cat ion: The product (s) must be completely characterized, including information on pulp source (hardwood/softwood), chemical additives (dyes, wet/dry strength additives, perfumes, etc.), and average use rates (sheetdday, etc.) and normal variation in product characteristics. If the tissue is
15、produced at more than one facility, the variability in tissue composition between plant locations must be provided. Effect on Septic Tank Operation: No gross impact on sludge or scum accumulation in the test tank versus the control tank, based on visual observations and sludge depth measurements, sh
16、all be observed over the course of the Initial Evaluation (see Section 4). Effect on Septic Tank Effluent: No statistical difference between the effluent quality (organics, solids) of the control tank versus the tank receiving the test tissue, based upon statistical evaluation described in the Initi
17、al Evaluation Method (Section 4). If specific ingredients in the tissues are identified which are of environmental concern, additional analyses may be required. Effect on Effluent Screens: No statistical difference between the control and test tanks in terms of effluent screen observations, based up
18、on statistical evaluation described in the Initial Evaluation Method (Section 4). Agreement for Use of Protocol Certification: Written agreement must be entered into between NSF and the Company before NSF authorizes the use of the P rotoco I Ce rtif cat ion. Changes to Product with Protocol Certific
19、ation: NSF must be informed in writing of any proposed changes in the product which carries the Protocol Certification. Copyright O 1993 NSF International Page 3 of 8 NSF will determine if the changes warrant additional product testing, or if the change will not affect the products suitability for s
20、eptic system disposal. Written authorization by NSF must be received prior to implementation of the changes, if the Protocol Certification is to be used on the product. SECTION 4. INITIAL EVALUATION METHOD 4.0 Summary In this method, two full-scale septic tanks are dosed with wastewater and two diff
21、erent bathroom tissues (one control and one test product) over a period of six months. Conditions in the septic tanks (including surface scum and sludge accumulation) are monitored periodically and samples of the inflowing wastewater and outflowing treated wastewater are removed for analysis (organi
22、c and solids content). Organic material is measured using a surrogate parameter (5-day Biochemical Oxygen Demand, Chemical Oxygen Demand or Total Organic Carbon). A statistical analysis of the effluent quality from the two tanks, and a qualitative comparison of scum and sludge accumulation in the ta
23、nks is performed. 4.1 Test System 4.1 .I Test Site The study will be performed at the NSF Wastewater Technology Site in the Village of Chelsea, Michigan, which is operated by NSF for testing and evaluation of a wide variety of wastewater treatment equipment. The Chelsea location provides an essentia
24、lly domestic wastewater, collected from homes and commercial buildings, with only minor industrial and commercial components. Raw wastewater used for dosing the septic tanks is obtained from one of two interceptor sewers to the Village wastewater treatment plant using an in-line diverter and an eigh
25、t- inch branch sewer. The sewage flows through a quarter-inch slot comminutor and is pumped through a dosing loop in the NSF site control building. Electrical controls in the dosing loop permit delivery of specific sewage volumes to individual dosing tanks, which then discharge discrete doses of was
26、tewater to the tanks used in the study. This special dosing equipment allows simulation of various domestic wastewater flow patterns. The effluent from the tanks, and other wastewater generated at the site, is &turned to the interceptor sewer for treatment at the Chelsea treatment plant. schematic o
27、f the site is shown in Figure 1. Copyright O 1993 NSF International Page 4 of 8 Wastewater Treatment Pla I I I 4 I I I I I I I I I I I I I I I I I I I I I I / c 4 I I I I I I I I I I I I I I I I I I I I I I I I I II- J I F- I I 1- - - - - - - - - m I L A u Mdhn6eSsta I I I I - - - - - I Site 1 U I I
28、 I I I I I I I I I I I I I I LI-+ I I I I I I I I n Village of Ck 3 Figure 1. Schematic of NSF Wastewater Technology Site Copyright O 1993 NSF International Page 5 of 8 Prior to the start of test material dosing, each tank is filled with anaerobic digester sludge from the Northfield Township (Michig
29、an) Wastewater Treatment Plant. The sludge has an initial total solids concentration of approximately two percent (20,000 mg/L), with a total volatile solids of approximately 50 percent. As soon as the sludge is placed into each tank, wastewater dosing begins and continues for a minimum of one month
30、 to provide time for the tanks to equalize. Effluent Total Organic Carbon and Total Suspended Solids (TSS) will be analyzed twice weekly during the last two weeks of the month-long start-up period to demonstrate equivalency between the two tanks. The effluent values from the two tanks must be within
31、 10 percent of the mean to est ab I ish eq u ivalen cy. 4.1.3 Wastewater Dosing Village of Chelsea wastewater is used as influent for the septic tanks (after passing through a quarter-inch slot comminutor). The wastewater has average chemical characteristics: Approx. average 5-day biochemical oxygen
32、 demand 200 Total suspended solids 240 Range 100-300 150-350 Each septic tank is dosed with approximately 250 gallons of wastewater per day. This results in a hydraulic residence time of 4 days (1000 gallons/250 gallons per day). Discrete doses of 6.25 gallons enter each tank according to the follow
33、ing schedule: 6 a.m. - 9 a.m. 11 a.m. - 2 p.m. 5 p.m. - 8 p.m. 14 doses = 87.5 gallons 1 O doses = 62.5 gallons 16 doses = 1 O0 gallons (35% of total daily flow) (25% of total daily flow) (40% of total daily flow) 4.1.4 Product Dosing The control and test products are dosed daily to the septic tanks
34、 using automatic dosing devices. The dosing rate is set to be equivalent to approximately 2.5 times the average use rate of a family of five persons. Specific dosing rates will be determined in discussions between NSF and the sponsor of the study. The automatic dosing devices are activated by the wa
35、stewater dosing system, with a representative tissue amount being dosed with each wastewater dose. The dosing devices are loaded daily. Any product remaining in the dosing mechanism at the end of a 24 hour dosing period is placed in the influent pipe at the time the dosing device is reloaded. 4.1.5
36、Effluent Sample Collection Effluent passing from the septic is collected using automatic samplers. The samplers are activated by the wastewater dosing system, with a sample being collected each time a wastewater dose is made to the tanks. The samples are collected in a container to provide for a 24
37、hour composite sample. Tees placed in the discharge line from each tank facilitate collection of the sample. Copyright O 1993 NSF International Page 6 of 8 The effluent from each tank passes through a one-eighth inch opening wire cloth screen to capture any large solids that pass from the tank. The
38、screen is placed in the sample tee, and captures solids after sampling. The materials captured on the screen are evaluated and grades are assigned based on the amount of material captured on the screen. A numerical grade is assigned based on the total amount of material on the screen and an alphabet
39、ical grade is assigned based on the amount of identifiable product captured on the screen: System Component Grade Screen Observation Frequency Sampling/ Proced Ure Analyses Nothing on screen. Trace amount of material on screen. More than a trace amount, but not more than : inch of screen height cove
40、red by material. More than : inch, but not more than 2 inches of screen height covered by material. More than 2 inches of screen height covered by material. Septic Tank Grade Screen Observation Center 2 timedweek In-place Temperatu re thermocouple A B C D E Bottom Tank Effluent No identifiable tissu
41、e on screen. One to five pieces, but less than one full sheet of tissue on screen. More than five pieces, but less than one full sheet of tissue on screen. At least one full sheet but less than 8 full sheets of tissue on screen. More than 8 full sheets of tissue on screen. At beginning and Measureme
42、nt using Sludge depth in 15 end of study “Sludge Judge“ locations in tank 2 timedweek 24-hour composite Organic*, TSS, pH samdes 4.2 Experimental Design A summary of the sampling and analyses during the study are shown in Table I. This sampling and analytical plan may be modified based upon the part
43、icular characteristics of the test product. Table I. Summary of Experimental Design I At mid-point and Access through tank Scum thickness I end of studv covers I and observations * Organic parameter, such as BOD, COD or TOC, depending on product formulation. Copyright O 1993 NSF International Page 7
44、 of 8 4.3 Statistical Methods Effluent quality parameters are compared between the two tanks to determine if there are any statistically significant differences between tank performance. Determination of statistical significance is evaluated at the 95 percent confidence level. Effluent chemical qual
45、ity difference (organic parameter, TSS) is evaluated using a one tailed t-test, based on a twoEffIuent screen grades are evaluated separately, using a Chi-square frequency test, called McNemars test for correlated proportions. For the general screen grades, grades of O or 1 are positive and grades of 2, 3 or 4 are negative. For the product specific screen grades, grades of A or B are positive and grades of C, D or E are negative. Copyright O 1993 NSF International Page 8 of 8
