Wastewater Treatment Plant for a Stevia Refinery Plant 

Project Description: To construct a Wastewater Treatment Plant for a Stevia Refinery Plant in Bandar Enstek, Negeri Sembilan.

Product Used in this Project:​

In this Project, Watterson has been entrusted to design and build a wastewater treatment plant to treat Production Process Wastewater to comply with DOE Standard A discharge limit. The WWTP was design as per influent parameter as listed in Table 1:Column 2 and is to comply with the guaranteed treated effluent quality as listed in Table 1: Column 3 (DOE Standard A)


The first part of the WWTP system is the Chemical Treatment System, while the second part of it is a Biological Treatment System. The second part of the treatment is consists of both attached growth and suspended growth biological system. Each part of the treatment system consists of tank/system as listed under Table 2 below:

Table 1: Comparison of Influent Parameter and DOE Standard A

Figure 1: Flowchart for WWTP Treatment System

Table 2: WWTP Treatment System

Figure 2: Wastewater Sample from each process

Equalization of Wastewater

Emergency Equalization Tank

Equalization Tank

The emergency EQ Tank (EEQ) is design for temporary storage of high loading (high flowrate, high COD/BOD) and high temperature raw wastewater from production. This is important as to prevent shock loading from entering into the treatment system.

The Equalization Tank is design to provide sufficient storage of the incoming wastewater for homogenization of pH, COD/BOD, temperature before transfer to chemical treatment.

Chemical Treatment

Chemical Reaction Tank

Coagulation Tank

Flocculation Tank

Chemical treatment consists of Chemical Reaction Tank, Flocculation Tank and Adjustable Inclined Plate Clarifier. Watterson's Adjustable Incline Plate Clarifier are designed for easy maintenance. All the inclined plates are fabricated from SS304 plates therefore would have a smooth surface which prevent sludge attachment and clogging problems. During maintenance or cleaning period, the inclined plates could be adjusted from its operation angle of 55° to a 90° position (Vertical), in order to let the attached sludge on inclined plates to slide down to the bottom of the clarifier easily with the help of water jet.


Anti-Clog Lamella Clarifier Tank

Moving Bed Bio-Reactor System

Moving Bed Bio-Reactor (MBBR) Chips

Air Distribution System - Preforated Pipe


Moving Bed Biofilm Reactor or MBBR is an attached growth biological treatment system which designed to remove high strength COD/BOD wastewater by providing high surface are per m³ of MBBR media for microorganisms to grow on.

Aeration Tank

Aeration Tank

Complete Mix Activated Sludge System or CMAS System is designed into this treatment plant in order to provide proper mixing of activated sludge and supply oxygen for bio-degradation process and at the same time maintaining proper condition for the suspended growth of the micro-organism system

Fine Bubble Diffuser Tubes

Membrane Bio-Reactor

Membrane Bio Reactor (MBR)

The Membrane Bio Reactor or MBR is a process technology which consists of a suspended growth biological reactor integrated with an ultra-filtration membrane system. The ultra-filtration replaces the solids separation function of secondary clarifier and sand filter of a conventional activated sludge system. 

Membrane Bio Reactor (MBR) Permeate Tank

MBR permeate tank is designed to have a function of storing MBR permeate which requires to be use during periodic MBR flushing and MBR soaking

Final Discharge

Final Discharge Tank shows crystal clear discharge in compliance to DOE Standard A

With the usage of Moving Bed Bio-Reactor (MBBR) and Membrane Bio-Reactor technology in treating the wastewater, the quality of the final discharge meet the stringent DOE Standard A quality and also achieve a crystal clear discharge which is safe for the environment. 

Filter Press and Chemical Dosing System

Filter Press

Chemical Dosing System

The thickened sludge form the Sludge Holding Tank is then fed into a filter press for further de-watering to achieved 25% dryness for sludge cake before it is disposed to DOE approved scheduled waste management center. The filtrate from the filter press is then channeled back to the Raw Sump.

All chemical dosing tanks, dosing pumps, and chemical preparation shall be done in this room shown above