Prosecution Insights
Last updated: April 19, 2026
Application No. 18/286,016

HUMAN WASTE PROCESSING APPARATUS AND METHOD

Non-Final OA §103
Filed
Oct 06, 2023
Examiner
ALI, WAQAAS A
Art Unit
1777
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Cranfield University
OA Round
1 (Non-Final)
81%
Grant Probability
Favorable
1-2
OA Rounds
2y 8m
To Grant
99%
With Interview

Examiner Intelligence

Grants 81% — above average
81%
Career Allow Rate
432 granted / 535 resolved
+15.7% vs TC avg
Strong +18% interview lift
Without
With
+18.3%
Interview Lift
resolved cases with interview
Typical timeline
2y 8m
Avg Prosecution
30 currently pending
Career history
565
Total Applications
across all art units

Statute-Specific Performance

§101
0.8%
-39.2% vs TC avg
§103
38.2%
-1.8% vs TC avg
§102
29.6%
-10.4% vs TC avg
§112
22.0%
-18.0% vs TC avg
Black line = Tech Center average estimate • Based on career data from 535 resolved cases

Office Action

§103
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Status Claims(s) 1-30, is/are filed on 4/1/2024 are currently pending. Claim(s) 26-30 is/are withdrawn as elected without traverse, 1-25 is/are rejected. Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. The following is a quotation of pre-AIA 35 U.S.C. 103(a) which forms the basis for all obviousness rejections set forth in this Office action: (a) A patent may not be obtained though the invention is not identically disclosed or described as set forth in section 102 of this title, if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains. Patentability shall not be negatived by the manner in which the invention was made. The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under pre-AIA 35 U.S.C. 103(a) are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention. Claim(s) 1-4, 10-23 is/are rejected under 35 U.S.C. 103 as being unpatentable over CATH (US 20100089830 A1) in view of O'REGAN (US 8246829 B2). PNG media_image1.png 420 516 media_image1.png Greyscale Regarding claim 1, CATH teaches human waste processing apparatus (intended use) comprising: a membrane distillation unit having a membrane distillation vessel (128) with an internal filter membrane (136), a primary flow liquid inlet (line from 114 to 116) and outlet and a permeate flow outlet (line from 188 to 164) [0048-0056], the primary flow liquid inlet connected in fluid communication to the liquid flow outlet of the pre-filter treatment unit; a flow actuator (120) to drive a flow of waste liquid through the pre-filter treatment unit and in a flow direction towards the membrane distillation unit. CATH does not teach a pre-filter treatment unit as claimed. O’REGAN teaches a pre-filter treatment unit (402, 410) having a pre-filter storage tank (410), a particulate filter (402) to separate particulate suspended within waste liquid and a liquid flow inlet and outlet before membrane distillation unit (430) (C14/1-25). It would have been obvious to a person of ordinary skill in the art before the effective filing date to combine the pre-filter treatment unit of O’REGAN with the membrane distillation system of CATH to remove particulates upstream of the membrane distillation unit, thereby preventing membrane fouling and extending system lifespan in human waste processing, as both references address wastewater purification including human waste fluids. Regarding claim 2, O’REGAN teaches the pre-filter treatment unit comprises a first pre-filter treatment unit (402, 410) having a first pre-filter storage tank (410) and a first particulate filter (402) (C14/1-225). Regarding claim 3, CATH does not teach the claim. Note that second pre-filter treatment as claimed is optional. Secondly, adding an additional pre-filter with a lower pore size, effectively creating a multi-stage, cascading, or gradient filtration system, is often considered well-known in the context of filtration engineering as this reduces the load and often (see at least US 12053726 B2 - Multi-stage Filter: Discusses a multi-stage system (often using pre-filters in series) the first stage filter having a body portion comprising a plurality of openings having a size that is larger than the size of the openings of the second stage filter. Where the pre-filter removes larger particles to protect the main filter) (C1/55-65, C2/29-35). Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date to have incorporated these teachings for the aforesaid advantages. Regarding claim 4, CATH does not teach the claim. Note that second pre-filter treatment is optional. Secondly, adding an additional pre-filter with a lower pore size, effectively creating a multi-stage, cascading, or gradient filtration system, is often considered well-known in the context of filtration engineering as this reduces the load and often (see at least US 12053726 B2 - Multi-stage Filter: Discusses a multi-stage system (often using pre-filters in series) the first stage filter having a body portion comprising a plurality of openings having a size that is larger than the size of the openings of the second stage filter where the pre-filter removes larger particles to protect the main filter) (C1/55-65, C2/29-35). wherein the first and/or second pre-filter treatment unit comprise respective mountings (74 and 76) to releasably mount the first and/or second particulate filters to enable removal and insertion of the first and/or second particulate filters at the respective first and/or second pre-filter treatment units. Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date to have incorporated these teachings for the aforesaid advantages. Regarding claim 10, CATH teaches a holding tank (110) positioned in a fluid flow direction between the pre-filter treatment unit and the membrane distillation unit. Regarding claim 11, CATH teaches comprising a first distillation flow pump (120) to drive a flow of liquid from the holding tank to the membrane distillation unit [0049]. Regarding claim 12, CATH teaches comprising at least one heater unit (i.e. heat source, such as power plant or factory, to provide the desired temperature differential or heat exchanger) [0021, 0096] connected in fluid flow communication with the membrane distillation unit to heat waste liquid transferred to the membrane distillation unit. Regarding claim 13, CATH teaches a waste liquid feed conduit (conduit attached to 152) connected in fluid flow communication with the primary flow liquid inlet and outlet of the membrane distillation unit to provide a waste liquid feed loop (fig. 1). Regarding claim 14, CATH teaches claim 13 comprising a first distillation flow pump (120) [0049] to drive a flow of liquid from the holding tank to the membrane distillation unit and at least one heater unit (i.e. heat exchanger) [0096] connected in fluid flow communication with the membrane distillation unit to heat waste liquid transferred to the membrane distillation unit, wherein the waste liquid feed loop comprises the first distillation flow pump and the heater unit such that waste liquid is capable of being circulated through the first distillation flow pump, the heating unit and the membrane distillation unit as a liquid flow loop (loop formed by 152, 110, 124) (intended use). Regarding claim 15, CATH teaches a holding tank (110) positioned in a fluid flow direction between the pre-filter treatment unit and the membrane distillation unit, wherein the waste liquid feed loop also comprises the holding tank, wherein the holding tank comprises a first inlet (inlet into 110) to receive waste liquid from the waste liquid feed loop conduit and a second inlet (inlet from 124) to receive waste liquid from the pre-filtration unit (fig. 1). Regarding claim 16, CATH teaches the holding tank further comprises at least one outlet (outlet from 110) provided in fluid flow communication with the membrane distillation unit, the first distillation flow pump and/or the heater unit (fig. 1). Regarding claim 17, CATH teaches a permeate collection reservoir (164) to collect liquid permeate output from the permeate flow outlet (fig. 1). Regarding claim 18, CATH teaches wherein the membrane distillation unit further comprises a permeate flow inlet (inlet of 132, i.e. from 178) connected in fluid flow with the permeate flow outlet (outlet of 132, i.e. 188) to provide a permeate flow loop through the filter membrane (fig. 1). Regarding claim 19, CATH teaches a holding tank (110) positioned in a fluid flow direction between the pre-filter treatment unit and the membrane distillation unit; a first distillation flow pump (120) to drive a flow of liquid from the holding tank to the membrane distillation unit; and a second distillation flow pump (170) connected in fluid flow with the permeate flow loop (fig. 1). Regarding claim 20 and 25 CATH does not teach a permeate output filter made of carbon connected in fluid communication to an outlet (outlet of 164 via 184) of the permeate collection reservoir to receive and collect output from the membrane distillation unit. However, it is well-known to use carbon filters post membrane distillation to remove any unwanted. CN 101490269 B also teaches active carbon filter (17) helps absorbs very low concentration impurity from aqueous stream of membrane distillation unit (16) (p. 1-3). CN 206965441 U teaches using a carbon filter (22) to prevent corrosion products, and degradation products which would prevent equipment damage (p. 1-3). Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date to have incorporated a carbon filter as claimed for the aforesaid advantages. Regarding claim 21, CATH teaches the membrane distillation unit comprises a configuration being any one of: direct contact membrane distillation (DCMD); *air gap membrane distillation (AGMD); * sweep gas membrane distillation (SGMD); * vacuum membrane distillation (VMD) (the reference teaches VE-DCMD) [0086]. Regarding claim 22, CATH may not teach the membrane distillation unit comprises an air gap membrane distillation configuration and the apparatus further comprises: a cooling fluid network having a fluid flow conduit to contain a cooling fluid, a cooling fluid tank, and a cooling fluid pump to drive a flow of the cooling fluid through the conduit. However, these are well-known alternative systems. See at least US 20160107121 A1. The reference teaches an air gap membrane distillation (AGMD) offers advantages over direct contact membrane distillation (DCMD) by reducing sensible heat loss from the feed due to air's lower thermal conductivity [0004]. This reduction in sensible heat transfer also helps mitigate temperature polarization issues present in DCMD [0003, 0004]. It has a cooling fluid network having a fluid flow conduit to contain a cooling fluid (fluid from 65), a cooling fluid tank (65), and a cooling fluid pump (68) to drive a flow of the cooling fluid through the conduit. It would have been obvious to a person of ordinary skill in the art before the effective filing date to have substituted AGMD with DCMD of CATH for the purpose of reducing sensible heat loss from the feed due to air's lower thermal conductivity which would also help mitigate temperature polarization issues. Regarding claim 23, CATH teaches a vacuum membrane distillation configuration and the apparatus further comprises: a vacuum manifold (piping attached to 170) having a vacuum pump (170) and a condenser (a heat exchanger fed by a water chiller) [0096] connected to the membrane distillation vessel to drive a flow of permeate from the membrane to the condenser [0059]. Claim(s) 5-9, 24 is/are rejected under 35 U.S.C. 103 as being unpatentable over CATH (US 20100089830 A1) in view of O'REGAN (US 8246829 B2) and GRAY (WO 02055182 A1). Regarding claim 5, CATH teaches wherein the first and/or second pre-filter treatment units comprise a respective purge valve and purge outlet connected in fluid communication to the respective particulate filters, the apparatus further comprising respective return flow conduits extending from the purge outlets to a front-end holding tank and/or the least one pre-filter treatment unit to provide a filtration circuit. However, this is well-known. GRAY to provides an additional purge valve (43) at purge outlet (17) to recycle fluid to holding tank (44) as this help improve efficiency, ensure high-quality purification, and prevent stagnation (p. 1-6, figs. 1-2). It would have been obvious to a person of ordinary skill in the art before the effective filing date to have incorporated said details for the aforesaid advantages. Regarding claim 6, CATH as modified teaches wherein the apparatus further comprises a supply flow conduit (outlet conduit from 116 > 120) connected in fluid communication to the front-end holding tank and the liquid flow inlet of the pre-filter treatment unit (fig. 1). Regarding claims 7-8, CATH does not teach teaches comprising a solid-liquid coarse filter to separate solid waste from the waste liquid positioned in a fluid flow direction upstream of the pre-filter treatment unit. However, this is well-known, see at least DE 3941673 A1. DE 3941673 A1 (fig. 1) teaches a solid-liquid coarse filter (3 and 4 auger) to trap relatively large particles from a surface of water drawn from vessel prior to filtering by pre-filter (6) (p. 1-3). Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date to have incorporated these teachings to prevent unwanted damage to the pre-filter of CATH. Regarding claim 9, CATH teaches wherein the flow actuator is a pump (120 - pump) connected in a fluid flow direction between the solid-liquid coarse filter and the pre-filter treatment unit [0049]. Regarding claim 24, CATH teaches the first particulate filter comprises a mesh pore size in a range 50 to 800 pm, 50 to 150 pm or 80 to 120 pm. However, this is merely matter of design choice to selectively choose an appropriate size that is best in removing unwanted particles. It is well-known it the art to have pre-filters within in this range prior to a membrane filtration system. For example, US 20050145548 A1 teaches a first and second pre-filter (61, 63) with a pore size of 100 and 25 microns prior to membrane filters (78, 80) to remove large particles that could potentially damage the membrane filter [0028-0035]. It would have been obvious to a person of ordinary skill in the art before the effective filing date to have selected the claimed pore size for the aforesaid advantage. *** It is noted that any citations to specific, pages, columns, lines, or figures in the prior art references and any interpretation of the reference should not be considered to be limiting in any way. A reference is relevant for all it contains and may be relied upon for all that it would have reasonably suggested to one having ordinary skill in the art. See MPEP 2123. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to Waqaas Ali whose telephone number is (571) 270-0235. The examiner can normally be reached on M-F 9-5 PM. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Claire Wang can be reached on 571-270-1051. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see http://pair-direct.uspto.gov. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /WAQAAS ALI/Primary Examiner, Art Unit 1777
Read full office action

Prosecution Timeline

Oct 06, 2023
Application Filed
Jan 24, 2026
Non-Final Rejection — §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
81%
Grant Probability
99%
With Interview (+18.3%)
2y 8m
Median Time to Grant
Low
PTA Risk
Based on 535 resolved cases by this examiner. Grant probability derived from career allow rate.

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