US-12625039-B2 - Apparatus and method for continuous monitoring and detection of microplastics in water

US12625039B2US 12625039 B2US12625039 B2US 12625039B2US-12625039-B2

Abstract

An automatic sampling device (autosampler) is provided for continuous water sample collection and visual inspection for the presence of particulate solids in water sources. The autosampler is capable of collecting larger water samples, over a longer period of time, than typical inline monitoring and sampling methods. This provides more accurate information regarding the presence and concentration of particulate solids in the water sample as compared to most inline methods. More particularly, the autosampler includes a plurality of plastic pellet and powder capture nets (P3CNs), each of which is designed with nested nets for catching and retaining particulate solids of sequentially diminishing particle size along the flow path of the water sample. This enables easy determination of the presence of particulate solids, as well as a quick assessment of the different sizes of particulate solids present in the water samples by visual inspection of the P3CNs.

Inventors

Carlos Alberto Hernandez Gutierrez

Assignees

Aizaco Limited Company

Dates

Publication Date: 20260512
Application Date: 20230601

Claims (20)

1 . An autosampler apparatus for automated monitoring and detection of microplastics present in water, the autosampler apparatus comprising: an autosampler body including: a top plate having a top plate edge, a bottom plate having a bottom plate edge which is coextensive with the top plate edge, a vertical wall extending between the top and bottom plates, and extending at least partially along the coextensive top plate edge and bottom plate edge; and three or more legs securely mounted to the autosampler body and which support and maintain the bottom plate of the autosampler a distance above ground level or other surface upon which the autosampler rests; a vertical shaft rotatably disposed within the autosampler body, wherein the vertical shaft extends at least from the top plate to the bottom plate and defines an axis of rotation within the autosampler body; a rotatable carousel disposed within the autosampler body and comprising a carousel plate having peripheral edge and a geometric center to which the vertical shaft is statically affixed, intermediate the top plate and bottom plate of the autosampler body, for rotating the carousel within the autosampler body, wherein the carousel plate has a plurality of sample openings therethrough which are distributed symmetrically and evenly around and proximate to the peripheral edge; a rotation motor which is mounted on the autosampler body, is in communication with the vertical shaft, and is capable of rotating the rotatable carousel via the vertical shaft; and a plurality of plastic pellet and powder capture nets (P3CNs) for receiving and filtering water which is provided thereto to detect the presence of microplastics in the water, wherein each P3CN has an upstream inlet end and an opposite downstream end, wherein each P3CN is mounted by its upstream inlet end to, in fluid communication with, a respective one of the plurality of sample openings, proximate the peripheral edge of the carousel plate and extending vertically downward from the carousel plate, and further wherein one or more of the plurality of P3CNs includes two or more compartments, which are at least partially nested together and each of which comprises a filter selected from a mesh and a net, and having an aperture or pore size which is selected to capture and separate a different size fraction of microplastics from water flowing through the one or more P3CNs, wherein the two or more compartments comprise at least a first filter comprising a relatively coarse first mesh and captures coarser microplastic pellets and broken pellets, and a second filter which at least partially surrounds the first filter and comprises a smaller, finer second mesh for trapping smaller microplastic powders.
2 . The autosampler apparatus of claim 1 , wherein water provided to one of the plurality of sample openings flows through a corresponding one of the plurality of P3CNs mounted thereto, from the upstream inlet end to the downstream end thereof.
3 . The autosampler apparatus of claim 1 , wherein each of the one or more P3CNs further includes a net body which surrounds both the first and second filters and extends from the upstream inlet end of the each of the one or more P3CNs to the downstream end thereof, wherein the net body comprises a second coarse mesh.
4 . The autosampler apparatus of claim 3 , wherein each of the first and second filter include a cutting guide line, respectively, to indicate to an operator or other user where to cut each filter for separation of the filters from the net body and each other, as well as removal and examination of each size fraction of microplastics captured by each filter.
5 . The autosampler apparatus of claim 1 , wherein each of the plurality of P3CNs has a P3CN length, the longest of which is less than the distance of the bottom plate of the autosampler from the ground level or other surface upon which the autosampler rests.
6 . The autosampler apparatus of claim 1 , wherein the plurality of P3CNs comprises twelve or more P3CNs.
7 . The autosampler apparatus of claim 1 , wherein the top plate has a first recess for allowing water to enter the autosampler body, and the bottom plate has a second recess substantially aligned with the first recess for allowing water to exit the autosampler body after being filtered.
8 . The autosampler apparatus of claim 7 , wherein rotation of the carousel sequentially aligns each of the plurality of P3CNs with and between the aligned first and second recesses of the top and bottom plates, respectively, of the autosampler body, which further enables water to be sequentially provided to each of the plurality of P3CNs through the first recess.
9 . The autosampler apparatus of claim 1 , further comprising a plurality of flow guards, each of which is mounted to and extends downward from carousel plate and surrounds a corresponding one of the plurality of P3CNs, each flow guard having an open bottom end for allowing water leaving the corresponding one of the plurality of P3CNs to continue on and leave the flow guard and autosampler body.
10 . The autosampler apparatus of claim 1 , wherein at least one of the plurality of P3CNs comprises an annular ring affixed to the upstream inlet end thereof for facilitating mounting to the corresponding one of the plurality of sample openings of the carousel plate.
11 . The autosampler apparatus of claim 1 , wherein at least one of the plurality of P3CNs is tapered from the upstream inlet end to the downstream end.
12 . The autosampler apparatus of claim 1 , wherein the vertical wall of the autosampler body extends partially along the coextensive top plate edge and bottom plate edge and, consequently, only partially surrounds the carousel disposed within the autosampler body, thereby allowing easy visual and physical access to the carousel and the plurality of P3CNs mounted thereon.
13 . The autosampler apparatus of claim 1 , further comprising a programmable logic controller (PLC) for controlling one or more components of the autosampler and operation of the autosampler, wherein the PLC is capable of receiving a selected sampling time and a selected speed or rate of rotation of the carousel and communicating this information to the rotation motor, thereby controlling rotation of the carousel.
14 . The autosampler apparatus of claim 1 , wherein water is provided to the autosampler apparatus through a conduit and a valve is provided on the conduit for controlling flowrate of the water therethrough.
15 . The autosampler apparatus of claim 1 , wherein water is provided to the autosampler apparatus through a conduit and a valve is provided on the conduit for controlling flowrate of the water therethrough, and wherein an actuator is connected to, and in programmable communication with, the valve, the actuator being capable of partially or fully opening and closing the valve, and wherein the PLC controls the flowrate of the water flowing through the conduit to the autosampler by controlling the actuator.
16 . The autosampler apparatus of claim 1 , further comprising a carousel locking system capable of pausing rotation of the carousel by intermittently and sequentially locking the carousel plate for a predetermined period of sampling time, wherein the carousel locking system comprises a mating feature on the carousel plate, a locking feature which is movable between an unlocked position in which the carousel is free to rotate and a locked position in which rotation of the carousel plate is prevented.
17 . The autosampler apparatus of claim 16 , further comprising a programmable logic controller (PLC) for controlling one or more components of the autosampler and operation of the autosampler, wherein the PLC is capable of receiving a selected sampling time and a selected speed or rate of rotation of the carousel and communicating this information to the rotation motor and the motor of the carousel locking system, thereby controlling rotation of the carousel and pausing of the rotation of the carousel.
18 . The autosampler apparatus of claim 16 , wherein the mating feature comprises a plurality of lock openings which are symmetrically and evenly distributed proximate the peripheral edge of the carousel plate, wherein each one of the plurality of lock openings is proximate a corresponding one of the plurality of sample openings and positioned in between each adjacent pair of the plurality of P3CNs; the locking feature comprises a bar lock having a contact end which is sized and shaped for lockingly engaging each one of the plurality of lock openings on the carousel plate, and a motor connected to and capable of reciprocatingly moving the bar lock between a retracted unlocked position in which the contact end is not in contact with the carousel plate or any lock opening, leaving the carousel free to rotate, and an extended locked position in which the contact end of the bar lock is securely received and mated in one of the plurality of lock openings.
19 . A method for sampling and detecting the presence of microplastics in water using the autosampler apparatus of claim 1 , wherein the plurality of P3CNs comprises a total of N P3CNs, where N equals two or more, the method comprising: confirming that the autosampler apparatus is positioned proximate an open end of a conduit, wherein the open end is aligned with an accessible one of the plurality of sample openings and the corresponding one of the plurality of P3CNs mounted thereto which is now the aligned P3CN; delivering water from a water source, at a selected flowrate, through the open end of the conduit, into the upstream inlet end of the aligned P3CN, through the aligned P3CN, and allowing filtered water to exit the downstream end of the aligned P3CN; automatically sampling the water, in predetermined water sample sizes and quantity of water samples for the presence of microplastics, over a selected total sampling period, by performing the sequential steps of: pausing rotation of the carousel for a predetermined period of sampling time; after passage of the selected sample time, rotating the carousel until a next one of the plurality of P3CNs, which is adjacent the aligned P3CN, is now aligned with the open end of the conduit and now becomes the aligned P3CN; repeating the sequential steps of pausing rotation and rotating the carousel a number of times equal to (N−1), so that each of the N number of P3CNs is used for filtering the water over the selected total sampling period.
20 . The method of claim 19 , wherein N equals 12 so that the plurality of P3CNs comprises 12 P3CNs, the predetermined period of sampling time is about 2 hours, and the selected total sample period is about 24 hours.

Description

The present application claims the benefit of U.S. Provisional Application No. 63/347,862, filed on Jun. 1, 2023, the entire disclosure of which is hereby incorporated by reference herein. FIELD OF THE INVENTION The present invention relates to apparatus and methods for monitoring and detecting particulate solids, especially microplastics, present in water, such as wastewater effluent streams and bodies of surface water. More particularly, the present invention relates to continuous automatic and remote monitoring and detection of microplastics present in water. BACKGROUND The growth in first world economies and the urbanization of developing countries continues to strain global water supplies. Even technologies utilized at water treatment facilities continue to advance, such facilities remain overburdened and often fall short when it comes to treating water to the point that it is useful for agriculture and human consumption. This is due, in part, to the fact that pollution today is more than just bulk items such as water bottles and trash, and today's wastewater treatment plants are not designed to accurately detect and measure the presence of some new forms of pollutants. Many particulate solids cause adverse impacts upon the environment but are also difficult to detect and remove from water. Microplastics are proving to be particularly difficult to detect and remove from water. Wastewater treatment plants and their technologies are now facing difficulties when it comes to detection and removal of certain particulate solid impurities, such as microplastics. In fact, wastewater treatment plants which inadequately detect or remove microplastics, as well as some nonpoint sources (e.g., stormwater discharges), may now be among the primary sources of microplastics in fresh waters and the ocean. This is because microplastics escape removal by conventional wastewater treatment technologies, whereupon they enter surface freshwaters and oceans and contaminate water resources like groundwater which might otherwise be reusable, and negatively impact terrestrial and aquatic environments. Accordingly, there is a growing need for water treatment technologies capable of detecting and removing smaller particulate matter, such as microplastics, which are not always captured by traditional mechanical (e.g., filtration, floatation, etc.) and chemical techniques (e.g., utilizing coagulants and oxidizing agents) for water treatment. Monitoring and detection of solid contaminants, such as microplastics and others, which may be present in water is sometimes performed using inline devices, such as a TSS sensor or an automatic sampling apparatus. These devices and apparatus are installed in a pipe through which water to be monitored and sampled flows. However, such inline devices provide information based on an instantaneous and relatively small sample of the water flowing through the pipe and such samples sometimes contain very few particulate solids. Furthermore, when the water being monitored and tested contains a relatively low concentration of particulate solids, such as microplastics, instantaneous water samples taken from that water often contain very few particulate solids. Water samples containing few particulate solids may not be sufficient to accurately detect the presence and concentration of particulate solids present in those water samples. However, it is important to be able to do so, even at such low concentrations, because the particulate solids, such as microplastics, may be present in amounts which nonetheless exceed the maximum allowable limit set by governmental authorities or other standard setting entities. The development of technology capable of monitoring and successfully detecting the presence of particulate solids, such as microplastics, in water such as wastewater, treated wastewater, bodies of surface water, etc., would contribute to the much-needed reusable water supply, as well as more accurately monitoring and determining whether such water meets the limits set by governmental authorities or other standard setting entities. BRIEF DESCRIPTION OF THE FIGURES The present invention will be further explained with reference to the attached drawings, wherein like structures are referred to by like numerals and/or letters throughout the several views. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the present invention. FIG. 1 is a perspective rear view of an exemplary embodiment of a continuous sampling device (i.e., an autosampler apparatus) in accordance with the description provided herein; FIG. 2 is a perspective side view of the autosampler apparatus of FIG. 1; FIG. 3 is a perspective left-rear view of the autosampler apparatus of FIG. 1; FIG. 4 is a top plan view of the autosampler apparatus of FIG. 1; FIG. 5A is an enlarged and slightly tilted view of the area indicated by dotted box B shown in FIG. 1; FIG. 5B is a