Glorinda’s services
Minimum Liquid Discharge
At Glorinda, we design and deliver Minimum Liquid Discharge systems that recover up to 85% of wastewater through reverse osmosis technologies, reducing the volume of concentrate that must be sent to evaporation or disposal.
Minimum Liquid Discharge
Minimum Liquid Discharge (MLD) is a wastewater treatment approach designed to minimise the amount of effluent discharged into the environment. It uses advanced filtration technologies to recover the maximum possible amount of water from wastewater streams, typically achieving around 85% water recovery.
Your solution can be MLD
“Effluent disposal costs more every year”.
What problem does it solve?
Compared with ZLD, MLD is a more common and cost-effective solution for many industrial sites while meeting environmental regulations. Glorinda provides customised MLD solutions for facilities that can legally discharge a small volume of concentrated wastewater and need to reduce the discharge of large volumes of diluted effluent.
Benefits
Around 85% recovery
Around 85% water recovery from wastewater streams, which on most sites is enough to release the abstraction constraint that was blocking expansion.
A cost-effective alternative to evaporation
MLD avoids the capital and energy cost of an evaporator train. Where a small concentrated discharge is permitted, that difference is usually decisive.
Compliance with room to move
A properly designed MLD system meets many environmental laws and restrictions while leaving headroom for the consent to tighten further before ZLD becomes necessary.
A stepping stone to ZLD
An MLD line built with the right pre-treatment becomes the front end of a ZLD plant later. Designing it that way costs little now and saves a rebuild if regulation moves.
How it works
Minimum Liquid Discharge (MLD) is a water recovery strategy based on membrane treatment stages. The engineering focus is on protecting the membranes and managing the concentrate, both of which depend on the wastewater analysis rather than the target recovery rate.
Glorinda designs each treatment stage to remove contaminants that could limit the performance of the next stage and defines the concentrate management route from the beginning, ensuring that the recovery target is supported by a complete treatment and reject management strategy.
01
Characterise and pre-treat
Suspended solids, organics, hardness, silica and the specific scaling species present decide the pre-treatment. Options range from dissolved air flotation and media filtration through ultrafiltration and ceramic or silicon carbide membranes to adsorbent systems where colour, metals or recalcitrant COD are present
02
Primary reverse osmosis
Conventional RO recovers the bulk of the water at low energy cost. Its recovery limit is set by the first species to reach saturation: usually silica, calcium sulphate or calcium carbonate.
03
High-recovery stage
Closed circuit RO recirculates concentrate within a closed loop, raising recovery without the long residence time at high concentration that causes scaling in a conventional array. High-efficiency RO operates at elevated pH, which keeps silica soluble and biological fouling suppressed. Selection depends entirely on which species limits you.
04
Permeate polishing and reuse
Permeate goes to cooling tower make-up, process water or boiler feed. Where boiler feed or ultrapure quality is required, ion exchange, mixed bed or electrodeionization follow.
05
Concentrate management
The remaining 15% or so is a small, concentrated stream. Where discharge is permitted it goes to consent. Where valuable salts are present or discharge closes entirely, it feeds an evaporation and crystallisation stage and the plant becomes ZLD.
Where this is used
Minimum Liquid Discharge is applied where high wastewater recovery is needed without the cost of full evaporation. Glorinda designs MLD systems using conventional, closed circuit, and high-efficiency reverse osmosis to recover up to 85% of wastewater across industrial treatment applications, reducing the volume that requires further concentration or disposal.
Oil, gas and petrochemical
Power generation
Food and pharma
Rubber manufacturing
Cement
Steel
Palm oil
Textile
Mining
Wood and paper
Electronic industries
Consumer goods manufacturing (CGMF)
Typical usages
- Rinse and wash water recycling
- Water footprint reduction programmes and ESG targets
- Debottlenecking a site whose abstraction licence is capped
- Cooling tower blowdown recovery
- RO reject recovery ahead of a smaller ZLD train
- Brackish water treatment for inland supply
Which MLD system suits your needs?
Selecting a process is an engineering decision, not a purchasing one. We run feasibility and pre-feasibility studies, characterise the stream, compare the routes on capital and operating cost, and act as owner’s engineer while somebody else builds it if that suits you better.
Related Technologies
Related Products
Frequently asked questions
MLD recovers around 85% using membranes and discharges a small concentrated stream. ZLD recovers close to 100% by adding evaporation and crystallisation and discharges nothing liquid at all. MLD is considered more common because it is less expensive while still meeting many environmental laws and restrictions.
Closed circuit RO recirculates concentrate in a closed loop, so the membranes spend less time exposed to peak concentration and recovery can be pushed without proportionally increasing scaling risk. HERO operates at elevated pH, which keeps silica soluble and suppresses biological fouling. If silica limits you, HERO is usually the answer; if scaling kinetics limit you, CCRO usually is.
Yes, and it is worth designing for. The concentrate from an MLD line is exactly the feed an evaporator wants. Sizing the pre-treatment and the concentrate handling with that in mind costs little now and avoids a rebuild if your consent tightens.
Take this further
Send us the stream data, the discharge limit or the equipment list you are working from. An engineer reads every enquiry and replies with the questions that actually decide the solution — not a brochure.