About us


Our Company

Association of Three Co.,Ltd. is a manufacturer of equipment for the “environmental industries” (the Three in the company name are earth, air and water, not people!). 

Thepthai Udomchanya started this company in 1993 and has built it into a very successful organisation supplying equipment for water and wastewater treatment throughout Asia and beyond. We have an excellent staff and workforce, many of whom have been with the company almost 20 years, and we make equipment which is technically superior, developed by the expert knowledge of our staff. We have a flexible and very capable manufacturing team, so we can make each unit as you need it, to match your exact requirements. 

From 2004 we have expanded our field of activity into the “earth” part of Association – Solid Waste. This will also benefit our third environmental discipline, “air”. 

Our Aims
  • To build equipment to protect the environment
  • To continually improve our work and designs through innovation and R&D
  • To develop staff and provide promotion opportunities for competent staff
  • To expand international sales whilst maintaining local competitiveness
  • To promote Quality of Life for all employees and to enjoy our work


Our Objectives
  • To make a reasonable profit
  • Safety and Good Environmental Approach
  • Customer & Employee Satisfaction


Our Products
Our approach is: 
We deliver solutions appropriate to Thai and Asian problems by developing and producing equipment in Thailand. So our equipment:
  • meets our Customers needs,
  • is affordable,
  • is maintainable locally
  • can be modified if needs change. 

We design and fabricate equipment to suit your particular requirements. Our main products are described below, but we do make other items to order. We are flexible and innovative, seeking to continuously develop our capabilities. If there is a product which you would like us to make for you, please ask and we will give your requirements detailed consideration.

Even though our equipment is very high quality, you will find it is not expensive.

We make a variety of equipment for water, wastewater and solid waste applications. This is a short summary of the items more fully described in “Products” elsewhere on the website.

Water and Wastewater
We make SEVEN patterns of screens,
  • 3mm or 5mm aperture fine screens which are developed from the “Aquagard” pattern.  We make this as a channel fitting model, for small or large works.  It needs no special concrete features.  It comes completely pre-assembled and has no fixings below deck level, so is easily installed.  The tines are made from a very high quality ABS we have developed, and are very durable.  We also manufacture small units in their own tanks for industrial use, particularly in food preparation industries.  These just fit onto the end of a pumping main and stand wherever the customer needs them.  They have been very well received in Thailand.   
  • A bar screen of original design which can be installed in channels, or in deep shafts as pump protection screens.  Some are installed 14m below ground, and there is no theoretical limit to the depth of the shaft in which they can be installed.  Bar spaces can be 25mm upwards, and 50mm is typical. They were designed to be installed on waterworks intakes for catching large material, but are very suitable for installation on deep sewers upstream of sewage works inlet pumping stations and upstream of fine screens for catching larger material.
  • Trash screens for multiple intakes, where a travelling frame carries a raking machine to serve any number of screens over each intake opening.
  • Front raked trash screens for single intakes, designed to remove floating material and large objects such as logs. 
  • Travelling band screens to remove smaller material from intake streams
  • Trash Rake Cleaner, where one overhead rake cleaner cleans several channels and discharge them at pre-determined points.
    And, Climber Screen suitable for various wastewater influent pumping stations.

We also make:

  • Screw conveyors and compactors for screenings handling.  These are generally shaftless but we can make them any pattern you would like.
  • Travelling bridge systems for grit removal and rectangular sedimentation tanks.  For grit removal we normally supply airlifts, air bubblers and scum skimmers.  For sedimentation tanks we can supply blade scrapers or hydrostatic sludge suction systems which are suitable for lightweight sludges
  • Non-metallic chain and flight scraper systems for rectangular sedimentation tanks and rectangular thickeners.  These lightweight and very robust systems are very much less prone to wear than other systems.  The one piece link design fits the same sprockets as American standards so we can replace others equipment and reduce maintenance. 
  • Circular tank bridges, scrapers and thickeners, hydrostatic sludge suction systems and high rate filter distributors, all using our unique CenterDrive unit which is an engineering masterpiece
  • Aeration diffusers fitted with membranes we have developed.  These are cured using H2O2 not sulphur.  They take longer to manufacture.  These are the strongest and most flexible and the best you can buy for the high temperature conditions which are a problem in tropical countries.  We normally supply these in pipe systems, but we also supply them as aeration mats which do not require tanks to be emptied for installation and are suitable for placing in ponds.   
  • Coarse bubble diffusers designed for scum and grease removal, used in conjunction with chain and flight scum skimmers.  These are manufactured in stainless steel and are suitable as aeration equipment for contaminated wastewater. 
  • DAF plants designed and built to match customer specific requirements


Solid Waste
Thailand has grown dramatically in the last twenty or thirty years which has led to problems with waste. We have undertaken research, product development and trial projects, and we have formed joint ventures with European machinery manufacturers to develop our products. 

We have seen a prospect in turning undesired organic sludges into a high grade fertilizer. So, in 2004, with the support of DANIDA, we have participated in a Partnership Facility Program with Tim Envipro A/S, which is one of the leaders in Compost Machinery. Since then, we have been involved in the composting process and composting machinery. The result of this effort is that we now have a portfolio of excellent equipment which we manufacture in Bangkok to address our country’s needs.

We now manufacture a wide range of equipment for the various phases of waste handling. Our equipment is efficient and economical, and we think it will also be an attractive export. During the development of this part of our business we have worked on a variety of jobs for landfill reclamation and wood shredding, and we are now moving into the main work of addressing Thailand’s needs. 

From our R&D work we have concluded that separating organic material from the waste stream and composting it is the most appropriate Thai solution. This process not only produces a valuable soil improvement material, but on the way also separates other valuable materials for recycling. We have now executed several of these projects at Krabi in the south, MaeSai and MaeSot in the north, as process contractors. Project Profiles for Krabi and Mae Sai are available. 

During 2009 we are also developing with European partners a solid waste digestion facility at Korat. The large amount of waste we have to deal with at Korat justifies the complexity of this technology. 

The equipment we now produce is:

  • Trommel Screen.  We have introduced this machine through developing a partnership with TIM Envipro of Denmark, with the assistance of the Danish government’s DANIDA programme.  We now assemble this and other TIM designed equipment at our factory.  This large and robust unit has a rotating screen and four integral conveyors.  It very effectively separates large and small material.  It is powered by a large diesel or electric motor which drives a hydraulic motor serving the operating parts.  We make wheeled units for mobile use on landfill sites, or static units for permanent installation at compost plants. 
  • Wood chipper.  This is another machine designed by TIM Envipro.  This is again a very large, robust mobile unit which we have used on various sites.
  • Bio Shredder.  This is a smaller unit using similar technology which we have developed for permanent installations to shred the green waste input to the feed stream of the compost plant. 
  • Bag opener.  This unit is fitted to the feed belt of the mobile bio-shredder, and on the feed to the hand sorting conveyor.
  • Magnetic separator.  This unit is normally incorporated in the belt delivering the organic stream to the bio- shredder.
  • Conveyors.  Conveyors are the arteries of our composting plants, moving the streams of material through the various processes.  The trommel screen even has four belt conveyors built into it.  We make belt conveyors for simple movement, but we also make:
    • hand sorting belt conveyors which are wider and incorporate platforms and handrails and bag openers
    • shaftless screw conveyors for elevating and conveying
  • Baler.  Our balers are primarily designed for baling plastic for recycling.  We can produce them with or without automatic strapping.
  • Vibrating mesh screen to sort fine finished compost product from larger material which is returned to the composting process.
  • Plastic Suction system to remove small plastics from waste for recycling.


Our Track Record

We have produced much equipment over the years with repeat orders from satisfied customers. In the last ten years we have produced:

  • 100 WateRRake fine screens
  • 80 WateRRake coarse screens
  • 80 Mix&Move conveyor and compactor systems
  • 100 sets of PlastiChain chain and flight scraper systems for rectangular clarifiers
  • 40 sets of PlastiChain chain and flight scraper systems for rectangular DAF plants
  • 18 travelling bridge systems for grit or sedimentation tanks
  • 100 CenterDrive units
  • 30 bridge units with scrapers or thickeners for circular tanks
  • Over 200,000 Dair diffusers to complete 258 orders
  • 20 MicronBubble DAF plants
  • 12 composting Facilities for Municipal Wastes
  • 1 combined Biogas Composting Facility for Municipal, Food, and Market Wastes.

We concentrated initially on water and wastewater equipment, but since 2004 we have also built our solid waste and composting machinery. We will continue to be creative. 


Our Achievements
  • 1993: Company established
  • 1996: Built and installed equipment for over 20 WwTWs in Thailand
  • 1997: Manufactured our first WaterRake Fine Screen
  • 1998: First to manufacture driveheads with precision bearings – CenterDrive
  • 2000: Supplied kit for largest Rectangular Clarifier in Thailand – PlastiChain
  • 2001: Produced DAir membrane.  Higher temperature tolerance and higher tensile strength than any competitor product   
  • 2003: First Thai wastewater company to achieve ISO 9001: 2000
  • 2003: First Thai manufacturer to supply complete screening system to Bangkok Municipal Administration
  • 2004: Major export order for Wastewater Treatment in the Phillipines
  • 2006: Major export order for  Wastewater Treatment in Taiwan
  • 2007: Contract to supply speciality aeration system to Shell, one of the world’s biggest companies
  • 2007: First municipal waste composting project in Thailand
  • 2008: Expansion of manufacturing facilities to a second factory close to our base.
  • 2008: First Thai ‘Environment Machinery’ company to achieve ISO 9001-2008
  • 2010: Initial startup of Trommel Screen Production for Thailand Market with the cooperation with Tim Envipro A/s Denmark
  • 2010: Design and Build the very first Thailand Combined Biogas Power Plant/Composting Faciilty from Municipal and Food Wastes in Korat,  plant capacity is 230 TPD
  • 2011: First Export order of Trommel Screen to International Market
  • 2012: Contract on Operation of Municipal Solids Wastes Treatment Facility in Mae Sai Municipal, Chienrai Province.  We take the full overall responsibility of the plant we had built for 3 years against a fixed dumping charge per ton.




Our People
We have a team of forty, and whilst we will not include them all here, these are the principal technical people you may be involved with: 



Thepthai Udomchanya

Thepthai is our company founder and Managing Director, pictured here with our fine screens and conveyors at Bangkok Metropolitan Administration’s “BMA4” works in 2006. Thepthai is a mechanical engineer with a master’s degree in Environmental Engineering from University of Florida, USA.   Thepthai’s creativity and desire to produce only high quality equipment has been the strength of our business.


Vithawas Hutamecalin

Vithawas is Director and Process Specialist with a degree in chemical engineering and master’s degree in environmental engineering.

Vithawas is responsible for much of the innovative product development which has made our products so successful. 

Vithawas is also a founder of our company in 1993.


The Engineers

Chatnarong Yolsawat

Chatnarong is our Senior Engineer who oversees the design, procurement, assembly, test and commissioning of the Biogas Plant. Chatnarong is a mechanical engineer. He joined us in 2007.


Chaiwat Puangcharoen

Chaiwat is our Mechanical Engineer who oversees the sales of Solids Wastes Treatment Machinery, as well as  performs design consultation for clients on Solids waste Separation Plant.  He joined us in 2007.

Pongsak Srimulruang

Pongsak joined us in 2006, He performs engineering , production, installation and commissioning of various water treatment equipment, screens, DAF, Clarifiers. 
Sompong Khaisa-ard  

Sompong joined us in 2008, He is in charge of all machinery with hydraulic parts.  He has a background as Mechanical Engineering.  Currently, he oversees the manufacturing of Trommel Screens.

Dave Smith

Dave is a chartered Civil and Water Engineer and Project Manager from UK who works for us as a Principal Engineer on international sales and product development.  He has over forty years experience in water and wastewater.

He worked in Thailand in 1991 on Bangkok Wastewater Project, where he first met Thepthai.  His Consulting Engineering company, Plungington Water Engineering has worked on design and development of many of our products.


The Sales Team

International sales are handled by the Managing Director, Thepthai Udomchanya.  Khun Thepthai also handles solid waste marketing and business development 


Chorthip Saesalub

Chothip handles sales for water and wastewater products in Thailand.  She is also a specialist in diffuser sizing calculation, and performs laboratory analysis for our DAF clients.

Qualifications – Bachelor in Sciences (Environment). Chorthip joined us in 2003, she has been in the water business since her graduation
Saowalak Tibanguay

Saowalak joined us in 2009, She has a background in Mechanical Engineering.  Currently, she is an assistant to Chothip in Sales.  



Our Drawing Office

We have an enthusiastic team of engineers and draughtsmen many of whom we have trained ourselves from young men who joined us in the factory.  Pictured on the left, the chief draughtsman Winyoo Pamee, and his colleagues Nuphan Larnwong.  And joined us recently, Raweewat Phiromjeaw, a mechanical engineer specifically responsible for solid wastes equipment products.
Winyoo Pamee, Nuphan Larnwong

Raweewat Phiromjeaw





Our Facilities

Our factory and offices are sited just off Rama II Road, at Bangkhuntien, on the south western side of Bangkok, with a second site just a little further down the road, which we opened in 2008.  We fabricate and assemble equipment at both sites.  We subcontract locally the manufacture of many components, but for all of the items we subcontract we have developed the designs and specified the materials.  For most products we own the moulds.  We have a close relationship with our panel builder who produces equipment to all international standards.

We have a very stable supply chain and work closely with them to ensure that we produce a consistent product.  Our systems were already organised so that we achieved ISO 9001 certification in 2003 without difficulty.  

This picture shows our Shop Manager Chat Ruabruam with three of his team, building CenterDrives


Pongsit Jeerawatsakul

Pongsit is our Service Engineer who oversees the assembly, test commissioning,  and after sales service. Pongsit is an electrical engineer in profession  He joined us in 2004
Prakasit Intarasam-arng

Prakasit is a soil scientist, who specialize in compost technology.  He is currently the force behind our development in composting machine and its operational aspects.  He joined us in 2006.
Rachan Duangta

Rachan is our electrical technician who oversees the  assembly of control cabinet, and instruments.  He joined us in 2004.




Sukjai Udomchanya