HomeMy WebLinkAboutD_Loop_Compost_Pilot_TP-II_FINALDEPARTMENT OF COMMUNITY
AND ECONOMIC DEVELOPMENT
D_Loop Compost Pilot_TP-II_Final
A.ADMINISTRATIVE REPORT & DECISION
Decision: APPROVED APPROVED SUBJECT TO CONDITIONS DENIED
Report Date: May 21, 2026
Project File Number: PR26-000001
Project Name: Loop Compost Pilot Project
Land Use File
Number:
LUA26-000150, TP -II
Project Manager: Jill Ding, Senior Planner
Owner: King County Wastewater Treatment Division, 201 S Jackson St, Seattle, WA
98104
Applicant/Contact: Jordyn Marxen, King County WTD, 201 S Jackson St, Seattle, WA 98104
Project Location: 1200 Monster Rd SW, Renton, WA 98057 (APN 2423049006)
Project Summary: King County Wastewater Treatment Division is applying for a Tier II Temporary
Use Permit (TP) to continue the work under a previous TP (LUA21-000141) for
the Loop Biosolid Composting project at King County’s South Treatment Plant.
Under LUA21-000141, issued in May of 2021, the applicant obtained a Tier II
Temporary Use Permit to construct a pilot compost system at King County’s
South Treatment Plant which further processes Class B Loop® biosolids into a
Class A Loop compost. The pilot project is located near the center of the property
and occupies approximately 0.8 acres of the Treatment Plant located at 1200
Monster Rd SW (APN 2423049006). The 72.34-acre parcel is zoned Heavy
Industrial (IH). The applicant is applying for another TP to allow the pilot
program to continue operation until sufficient data can be collected as proof of
concept for a future permanent program. The current application requests a five
(5) year approval. The parcel contains moderate coal mine hazards, regulated
shoreline - shoreline high intensity, high seismic hazards, regulated slopes,
moderate/high landslide hazards, special flood hazard areas, and wetlands.
Site Area: 72.34 acres
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
City of Renton Department of Community & Economic Development
Loop Compost Pilot Project
Administrative Report & Decision
LUA26-000150, TP-II
Report of May 21, 2026 Page 2 of 9
D_Loop Compost Pilot_TP-II_Final
B.EXHIBITS:
Exhibit 1:Administrative Decision
Exhibit 2:Site Plan
Exhibit 3:Project Narrative
Exhibit 4:SEPA Response Comment Letter from King County, dated February 19, 2021
Exhibit 5:Utilities Plan
Exhibit 6:Technical Information Report (TIR), prepared by HDR, dated March 10, 2021
Exhibit 7:Geotechnical Hazard Review Report, prepared by Shannon & Wilson, dated March
26, 2021
Exhibit 8:Update Regarding Odor Monitoring and Community Engagement Memorandum,
prepared by King County, dated April 28, 2026
Exhibit 9:Abatement Agreement
Exhibit 10:LUA21-000141 Decision
Exhibit 11:LUA21-000141 Exhibits
Exhibit 12:Neighborhood Detail Map
C.GENERAL INFORMATION:
1.Owner(s) of Record:King County Wastewater Treatment Division
201 S Jackson St
Seattle, WA 98104
2.Zoning Classification:Heavy Industrial (IH)
3.Comprehensive Plan Land Use
Designation:
Employment Area (EA)
4.Existing Site Use:Westwater Treatment Plant
5.Critical Areas:Moderate coal mine hazards, regulated shoreline -
shoreline high intensity, high seismic hazards,
regulated slopes, moderate/high landslide
hazards, special flood hazard areas (FEMA Zone –
AE), and wetlands
6.Neighborhood Characteristics:
a.North:
Oakesdale Center and vacant land north of Oakesdale Ave SW. Employment Area
(EA) Comprehensive Plan Land Use Designation; Medium Industrial (IM) and
Commercial Office (CO), Resource Conservation (RC) and Commercial Office
Residential (COR) zone
b.East:
Office buildings east of Oakesdale Ave SW. Employment Area (EA)
Comprehensive Plan Land Use Designation; Heavy Industrial (IH) zone and
Commercial Office (CO) east of Oakesdale Ave SW
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
City of Renton Department of Community & Economic Development
Loop Compost Pilot Project
Administrative Report & Decision
LUA26-000150, TP-II
Report of May 21, 2026 Page 3 of 9
D_Loop Compost Pilot_TP-II_Final
c.South:
Office buildings, warehouse and vacant land. Employment Area (EA)
Comprehensive Plan Land Use Designation; Heavy Industrial (IH) zone and
Medium Industrial (IM) zone south of Jackson Pl SW
d.West:
Warehouse, office, packaging plant, minerals yard, and vacant land west of
Monster Rd SW/Jackson Pl SW. Employment Area (EA) Comprehensive Plan Land
Use Designation; Medium Industrial (IM)
7.Site Area:72.34 acres
D.HISTORICAL/BACKGROUND:
Action Land Use File No. Ordinance No. Date
Comprehensive Plan N/A 6153 01/01/2025
Zoning N/A 6160 06/24/2025
Annexation (S 180th) A-002-59 1745 04/19/1959
Conditional Use Permit
(Effluent Reuse Pilot
Project)
LUA95-073 N/A 04/28/1995
Temporary Use Permit
(Install/Operate Sludge
Reduction Building)
LUA99-129 N/A 09/14/1999
Shoreline Substantial
Development Permit (Odor
Control System for the
Eastside Sewer
Interceptor)
LUA00-017 N/A 02/08/2000
Temporary Use Permit
(Diesel Generators)
LUA01-022 N/A 02/20/2001
Conditional Use Permit
(Construct a Fuel Cell
Demonstration Project)
LUA01-138 N/A 10/03/2001
Site Plan Review (King
County South Plan Biogas
and Heating Systems
Improvements Project)
LUA18-000188 N/A 06/11/2018
Lot Combination (KC
Recording No.
20190228900013)
LUA18-000597 N/A 10/01/2018
Tier II Temporary Use
Permit (Loop Compost
Pilot Project)
LUA21-000141 N/A 05/25/2021
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
City of Renton Department of Community & Economic Development
Loop Compost Pilot Project
Administrative Report & Decision
LUA26-000150, TP-II
Report of May 21, 2026 Page 4 of 9
D_Loop Compost Pilot_TP-II_Final
E.APPLICABLE SECTIONS OF THE RENTON MUNICIPAL CODE:
1.Chapter 2 Zoning District – Uses and Standards
a.Section 4-2-020: Purpose and Intent of Zoning Districts
b.Section 4-2-060: Zoning Use Table – Uses Allowed in Zoning Designations
c.Section 4-2-130: Industrial Development Standards
2.Chapter 3 Environmental Regulations and Overlay Districts
a.Section 4-3-050: Critical Areas Regulations
3.Chapter 4 City-Wide Property Development Standards
4.Chapter 9 Permits – Specific
a.Section 4-9-240: Temporary Use Permits
5.Chapter 11 Definitions
F.FINDINGS OF FACT (FOF):
1.The Planning Division of the City of Renton accepted the above master application for review on April
29, 2026 and determined the application complete on May 1, 2026. Upon deeming the land use
application complete, the City issued a Notice of Application, which was mailed to the applicant,
property owner, and all property owners and tenants of record within three hundred (300) feet of the
site. The Notice of Application was also posted on the City’s website consistent with Renton
Municipal Code (RMC) 4-8-090C. The project complies with the Type II 100-day review time period.
2.The project site is located at 1200 Monster Rd SW, Renton, WA 98057 (APN 2423049006).
3.The project site is currently developed with the Loop Compost Pilot Project within the existing King
County South Treatment Plant.
4.No changes in vehicular or pedestrian access are proposed. Primary access to the site is provided
via Monster Rd SW.
5.The property is located within the Employment Area (EA) Comprehensive Plan land use designation.
6.The site is located within the Heavy Industrial (IH) zoning classification.
7.No construction impacts or tree removal are proposed with this Tier II Temporary Use Permit
application.
8.The site is mapped with moderate coal mine hazards, regulated shoreline - shoreline high intensity,
high seismic hazards, regulated slopes, moderate/high landslide hazards, special flood hazard
areas, and wetlands.
9.Staff received no public or agency comments.
10.Representatives from various city departments have reviewed the application materials to identify
and address issues raised by the proposed development. These comments are contained in the
official file, and the essence of the comments has been incorporated into the appropriate sections
of this report and the Departmental Recommendation at the end of this report.
11.Critical Areas: Project sites which contain critical areas are required to comply with the Critical
Areas Regulations (RMC 4-3-050). The parcel contains moderate coal mine hazards, regulated
shoreline - shoreline high intensity, high seismic hazards, regulated slopes, moderate/high landslide
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
City of Renton Department of Community & Economic Development
Loop Compost Pilot Project
Administrative Report & Decision
LUA26-000150, TP-II
Report of May 21, 2026 Page 5 of 9
D_Loop Compost Pilot_TP-II_Final
hazards, special flood hazard areas, and wetlands. However, the requested Tier II Temporary Use
Permit would not include construction but rather proposes to allow an existing pilot compost system
to continue operating at King County’s South Treatment Plant.
12. Temporary Use Permit (TP Analysis: The applicant, King County Wastewater Treatment Division
(WTD), is requesting up to a five (5) year Tier II Temporary Use Permit (TP) pursuant to Renton
Municipal Code Section 4-9-240 to continue the operation of an existing limited term pilot compost
system to process Class B Loop® biosolids into a Class A Loop compost at King County’s South
Treatment Plant (STP). According to the applicant, the facility is located at the site of the former fuel
cell demonstration project and has been designed to demonstrate the practicability of composting
of Class B Loop biosolids mixed with bulking agents, such as wood chips and yard clippings, at
various ratios to produce Class A biosolids. The purpose of the pilot project is to allow King County
WTD to demonstrate the business case for a full-scale Loop composting facility and evaluate various
blends of feedstock to determine the optimal conditions for proceeding forward with a full-scale off-
site facility. Due to unforeseen delays including budgeting, additional permitting, and contractor
obtainment, the construction of the site was not completed until NSovember 2024, at which
point composting began. WTD is applying for another temporary use permit to allow the pilot
program to continue operation until sufficient data can be collected as proof of concept for a future
permanent program. As only 18 months of pilot testing will have been accomplished by the time the
2021 permit expires, WTD is requesting this new temporary use permit be approved for a
minimum of five (5) years. The proposal is compliant with the following criteria, pursuant to
RMC 4-9-240J, if all conditions of approval are met. Therefore, staff is recommending
approval of the requested Temporary Use, subject to conditions as noted below:
Compliance TP Criteria and Analysis
✓
a.The temporary use will not be materially detrimental to the public health,
safety, or welfare, nor injurious to property or improvements in the vicinity of
the temporary use.
Staff Comment: The applicant contends that the existing pilot compost system is
not materially detrimental to the public health, safety, or welfare or injurious to
property or improvements in the vicinity. The project would not have any new
structures. The existing facility currently employs covered aerated static pile
composting technology, a Class A process, to further reduce pathogens under
WAC 173-308-170(3), using a bunker-style primary composting operation to fit
within a limited available area of less than one (1) acre. The facility would result in
air impacts related to odor and function in a series of batches based on the
amount of material received from the delivery of a single truck of Loop. According
to the applicant, the facility is equipped to receive up to a single truckload of Class
B biosolids per week, and it would be designed to process up to 780 wet tons per
year of Loop biosolids (15 wet tons per truck, delivered once per week, 52 weeks
per year). Mixing of biosolids with bulking material would occur on the same day
to reduce the propensity of odorous emissions. Depending on the density and
moisture content of the bulking material, approximately 600 to 1,300 tons per year
of bulking material would be needed to perform the proposed compost functions
(active composting would last 28 days per batch). The total facility throughput is
estimated at 1,400 to 2,100 tons per year and the facility bunkers and
infrastructure are sized to compost up to 70 cubic yards per week or
approximately 3,600 cubic yards per year. However, King County anticipates an
actual throughput range of 2,500 to 3,500 cubic yards per year, depending on the
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
City of Renton Department of Community & Economic Development
Loop Compost Pilot Project
Administrative Report & Decision
LUA26-000150, TP-II
Report of May 21, 2026 Page 6 of 9
D_Loop Compost Pilot_TP-II_Final
quantity of bulking material used and the timing of developing sequential batch
operations. A front-end loader would be used to move the material.
No permanent structures or buildings are proposed with this project. The project
site includes a temporary structure that consists of bunkers formed by temporary
ecology blocks stacked four feet (4’) high with bunkers ranging from 25 feet (25’)
wide by 25 feet (25’) long to 45 feet (45’) wide by 55 feet (55’) long and covered by
tent-like fabric structures that are not fully enclosed but are intended to provide
protection from rainfall. Much of the proposed project area is currently covered
with impervious to semi-impervious surface. No new impervious surfaces are
proposed with the continued operation of the ongoing pilot program.
During operations, King County WTD monitors temperature and pathogen density
on an ongoing basis. According to the applicant, if Class A requirements are not
met, King County WTD would follow the product quality contingency plan outlined
in the project’s approved operations plan. The contingency plan would include at
least two (2) options: 1) re-mix and re-compost the batch to meet process
requirements, or 2) land-apply the compost as Class B biosolids, according to the
existing DOE-approved Class B procedures. Similar to existing biosolids
management practices, if a compost batch were to fail to meet Class B biosolids
requirements, it would be landfilled. Once operational, information from the
composting pilot project would be used by King County WTD to demonstrate proof
of concept in order to construct an off-site permanent facility in the greater King
County region.
According to the applicant, King County WTD has operated an effective biosolids
program for the past 30 years and maintains a 24-hour odor control hotline which
is (206) 263-1760. Prior to permit issuance, the applicant would be required to
maintain the 24-hour odor control hotline at (206) 263-1760 throughout the
duration of the temporary use permit and provide an advertisement plan and
public outreach plan for review and approval.
The Loop biosolids program is used to build soil and provide nutrients for farms
and forests to improve crop yield and soil health. King County WTD expects the
current biosolids to increase year over year. The Loop® Compost Pilot Project is
considered to be the first step of the 2018-2037 King County biosolids program
Strategic Plan to address the current lack of redundancy in the biosolids program,
which has become reliant on farmers in Eastern Washington to manage the
majority (75% in 2016) of their biosolids.
The applicant submitted an update regarding odor monitoring and community
engagement at our composting facility memorandum (Exhibit 8). According to the
submitted memorandum, only one (1) odor complaint has been received which
can be attributed to the composting facility. Following the complaint, operational
processes were adjusted to allow the existing piles to mature more before turning.
Since that change was made, no further complaints have been received.
✓
b.Adequate parking facilities and vehicle ingress and egress are provided to
serve the temporary use and any existing uses on the site.
Staff Comment: No new structures are proposed that would warrant additional
parking. Existing parking and vehicular access are adequate for the temporary
use.
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
City of Renton Department of Community & Economic Development
Loop Compost Pilot Project
Administrative Report & Decision
LUA26-000150, TP-II
Report of May 21, 2026 Page 7 of 9
D_Loop Compost Pilot_TP-II_Final
✓
c.Hours of operation of the temporary use are specified, and would not
adversely impact surrounding uses.
Staff Comment: As previously discussed above, the applicant operates a 24-hour
odor control hotline for odor complaints. Since the compost system was
implemented, one (1) complaint was received, and after adjustments were made
to operational processes, no further odor complaints have been received. It is not
anticipated that the continuation of the existing temporary use would adversely
impact surrounding uses.
✓
d.The temporary use will not cause nuisance factors such as noise, light, or
glare which adversely impact surrounding uses.
Staff Comment: As previously discussed above, no new construction is proposed.
The continuation of the existing compost pilot project is not anticipated to result
in nuisance factors such as noise, light, or glare.
N/A
e.If applicable, the applicant has obtained the required right-of-way use permit.
Staff Comment: Not applicable, as no right-of-way use permit is required. The
existing pilot project is on private property.
G.CONCLUSIONS:
1.The proposed Temporary Use Permit complies with the Critical Areas Regulations provided the
applicant complies with City Code and conditions of approval, see FOF 11.
2.The proposed Temporary Use Permit complies with all five (5) Temporary Use criteria as established
by City Code provided all advisory notes and conditions are complied with, see FOF 12.
H.DECISION:
The Loop Compost Pilot Project Temporary Use Permit, File No. LUA26-000150, TP-II, as depicted in
Exhibit 2, is approved and is subject to the following conditions:
1.The site occupied by the temporary use shall be left free of evidence of the temporary use upon
completion of removal of the use or when the operation of the use ceases to exist.
2.The applicant shall maintain the 24-hour odor control hotline at (206) 263-1760 throughout the
duration of the temporary use permit. An advertisement plan and public outreach plan shall be
submitted to the Current Planning Project Manager for review and approval prior to permit issuance.
DATE OF DECISION ON LAND USE ACTION:
SIGNATURE:
Matthew Herrera, Planning Director Date
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
5/21/2026 | 3:17 PM PDT
City of Renton Department of Community & Economic Development
Loop Compost Pilot Project
Administrative Report & Decision
LUA26-000150, TP-II
Report of May 21, 2026 Page 8 of 9
TRANSMITTED on May 21, 2026 to the Owner/Applicant/Contact:
Owner: Applicant/Contact:
King County Wastewater
Treatment Division
201 S Jackson St
Seattle, WA 98104
Jordyn Marxen
King County WTD
201 S Jackson St
Seattle, WA 98104
TRANSMITTED on May 21, 2026 to the Parties of Record:
No parties of record
TRANSMITTED on May 21, 2026 to the following:
Gina Estep, CED Administrator
Justin Johnson, Development Engineering Director
Nathan Janders, Development Engineering Manager
Clark Close, Current Planning Manager
Anjela Barton, Fire Marshal
I.LAND USE ACTION APPEALS, REQUEST FOR RECONSIDERATION, & EXPIRATION:
The administrative land use decision will become final if the decision is not appealed within 14 days of the
decision date.
APPEAL: This administrative land use decision will become final if not appealed in writing to the
Hearing Examiner on or before 5:00 PM on June 4, 2026. An appeal of the decision must be filed within
the 14-day appeal period (RCW 43.21.C.075(3); WAC 197-11-680). Appeals must be submitted
electronically to the City Clerk at cityclerk@rentonwa.gov or delivered to City Hall 1st floor Lobby Hub
Monday through Friday. The appeal fee, normally due at the time an appeal is submitted, will be collected at
a future date if your appeal is submitted electronically. The appeal submitted in person may be paid on the
first floor in our Finance Department. Appeals to the Hearing Examiner are governed by RMC 4-8-110 and
additional information regarding the appeal process may be obtained from the City Clerk’s Office,
cityclerk@rentonwa.gov.
EXPIRATION: The Temporary Use Permit is valid for five (5) years from the effective date of the permit.
EXTENSIONS: No extension requests to this Temporary Use Permit will be accepted by the Department of
Community & Economic Development Administrator as the maximum permitted time has been granted by
this permit.
RECONSIDERATION: Within 14 days of the decision date, any party may request that the decision be
reopened by the approval body. The approval body may modify his decision if material evidence not readily
discoverable prior to the original decision is found or if he finds there was misrepresentation of fact. After
review of the reconsideration request, if the approval body finds sufficient evidence to amend the original
decision, there will be no further extension of the appeal period. Any person wishing to take further action
must file a formal appeal within the 14-day appeal time frame.
THE APPEARANCE OF FAIRNESS DOCTRINE: provides that no ex parte (private one-on-one)
communications may occur concerning the land use decision. The Doctrine applies not only to the initial
decision, but to Appeals to the Hearing Examiner as well. All communications after the decision/approval
date must be made in writing through the Hearing Examiner. All communications are public record and
this
D_Loop Compost Pilot_TP-II_Final
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
City of Renton Department of Community & Economic Development
Loop Compost Pilot Project
Administrative Report & Decision
LUA26-000150, TP-II
Report of May 21, 2026 Page 9 of 9
D_Loop Compost Pilot_TP-II_Final
permits all interested parties to know the contents of the communication and would allow them to openly
rebut the evidence in writing. Any violation of this doctrine could result in the invalidation of the appeal by
the Court.
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D
CITY OF RENTON
DEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT
ADMINISTRATIVE REPORT & DECISION
EXHIBITS
Project Name:
Loop Compost Pilot Project
Land Use File Number:
LUA26-000150, TP-II
Date of Report
May 21, 2026
Staff Contact
Jill Ding
Senior Planner
Project Contact/Applicant
Jordyn Marxen
King County WTD
201 S Jackson St, Seattle,
WA 98104
Project Location
1200 Monster Rd SW,
Renton, WA 98057 (APN
2423049006)
The following exhibits are included with the Administrative report:
Exhibit 1:Administrative Decision
Exhibit 2:Site Plan
Exhibit 3:Project Narrative
Exhibit 4:SEPA Response Comment Letter from King County, dated February 19, 2021
Exhibit 5:Utilities Plan
Exhibit 6:Technical Information Report (TIR), prepared by HDR, dated March 10, 2021
Exhibit 7:Geotechnical Hazard Review Report, prepared by Shannon & Wilson, dated
March 26, 2021
Exhibit 8:Update Regarding Odor Monitoring and Community Engagement Memorandum,
prepared by King County, dated April 28, 2026
Exhibit 9:Abatement Agreement
Exhibit 10:LUA21-000141 Decision
Exhibit 11:LUA21-000141 Exhibits
Exhibit 12:Neighborhood Detail Map
Docusign Envelope ID: EEA55307-2CCD-8A26-8319-F48B965DA53D