What treatment should a Comilla data center actually need?
A Comilla data center needs a source-specific treatment strategy, not one generic wastewater plant. First segregate cooling blowdown from sanitary and fabrication wastewater, then establish the source-water chemistry, cooling configuration, cycles of concentration and permitted discharge or reuse route. Cooling blowdown usually needs solids removal, hardness control, RO protection, conductivity-controlled reuse and biological or oxidant management. Bangladesh guidance prioritises household water, encourages closed-loop cooling and reuse of treated wastewater, and requires water withdrawals, consumption and environmental safeguards to be disclosed. Equipment sizing and final compliance must therefore follow Comilla-specific testing, DoE consent and site data rather than Chattogram figures or unverified regional assumptions.
The decision starts with four inputs: cooling technology and cycles of concentration, expected blowdown flow, source-water chemistry, and the permitted reuse or discharge destination. Until those are known, selecting an MBR, RO or zero-liquid-discharge train is premature. The treatment boundary may be reviewed against the data center wastewater and cooling blowdown treatment guide and data center wastewater treatment planning, but neither overrides Comilla site data.
Bangladesh has 48 operational data centres, about 200 MW of current demand and projected demand exceeding 500 MW by 2030, according to Climate Watch in 2026. The same source describes drinking, hygiene and sanitation as the highest water-use priorities under the Water Act 2013. The Business Standard reported the same priority in 2026 and recommends closed-loop or water-efficient cooling, treated-wastewater reuse, water-footprint disclosure, regular monitoring and drought contingency planning.
Do not transfer Chattogram groundwater chemistry, tariffs or discharge assumptions to Comilla. The supplied evidence contains no Comilla groundwater profile, water tariff, permit threshold or receiving-water limit. The defensible sequence is source sampling, a measured water balance, confirmation of the reuse or discharge route, and only then equipment selection.
Build a Comilla source-to-discharge water balance
Water balance must distinguish withdrawal from consumption because the water removed by evaporation is not returned to its source, whereas cooling blowdown may be discharged or recovered. The Business Standard reported this distinction in 2026. Install or plan separate metering for makeup water, evaporation, blowdown, process wastewater and final discharge; otherwise equipment sizing and reuse savings remain estimates.
HydropureWater’s Chattogram guide, published in 2026, reports that measured blowdown often exceeds theoretical calculations by 15–30% because of unmeasured losses and emergency dumps. It gives the blowdown relationship as 1/(CoC−1): at 4 cycles of concentration, blowdown is roughly 25% of makeup water; at 6 cycles, about 20%. Apply those relationships as checks, not as a substitute for operating data.
| Water-balance item | Measurement or definition | Procurement use |
|---|---|---|
| Makeup water | Separate meter at the source-to-cooling-system boundary | Establish withdrawal and source-water demand |
| Evaporation | Derived from a closed, calibrated water balance where practical | Quantify consumption rather than treating all withdrawal as consumption |
| Cooling blowdown | Continuous flow meter plus operating log | Size pretreatment, recovery and disposal equipment |
| Process wastewater | Separate stream meters and sample points | Prevent cooling-blowdown and sanitary flows from distorting sizing |
| Final discharge | Meter at the authorised discharge or reuse point | Verify the permit balance and water-reuse claim |
| Cooling-loop chemistry | Conductivity, pH and suspended solids monitoring | Set blowdown triggers and treatment duties |
Use a seasonal sampling programme for TDS, silica, hardness, iron and residual treatment chemicals. The water-treatment valves and media used for sampling and control should be selected around the actual analysis plan. Obtain Comilla source-specific chemistry before choosing softening, UF or an industrial reverse osmosis system for cooling-blowdown reuse; the research does not establish the local groundwater profile.
Compare cooling blowdown with other data-center wastewater
Cooling blowdown and fabrication wastewater require different process trains because their contaminants and acceptable endpoints differ. HydropureWater’s Chattogram guide identifies concentrated TDS, hardness, silica, trace metals, biocides, corrosion inhibitors and scale inhibitors in cooling blowdown. It separately characterizes fabrication UPW blowdown as organic, fluorinated and metallised, with different removal targets.
| Waste stream | Dominant treatment issue | Preliminary process direction | Do not assume |
|---|---|---|---|
| Cooling-tower blowdown | Dissolved salts, hardness, silica, particulates, corrosion products and residual chemicals | Filtration, hardness control, membrane pretreatment where justified, dissolved-solids removal, controlled reuse or discharge | That drinking-grade treatment or biological treatment is required |
| Sanitary sewage | Organic matter and pathogens | Biological treatment followed by disinfection, or a suitably specified package treatment | That the cooling-blowdown skid can substitute for an MBR or sewage package |
| Laboratory wastewater | Variable composition and chemical compatibility | Characterise each discharge before combining it with other streams | That dilution makes incompatible chemistry acceptable |
| Semiconductor-fabrication UPW blowdown | Organic, fluorinated and metallised contaminants with specialised removal targets | Separate process assessment, often requiring a distinct high-removal train | That it can share the cooling-blowdown RO simply to simplify the P&ID |
The Business Standard reported in 2026 that data centres do not necessarily need drinking-quality water: river water, treated wastewater and seawater may be options depending on technology, water quality, seasonal availability, corrosion and ecological effects. Treated wastewater can reduce freshwater reliance only when it meets the cooling system’s technical requirements.
Sanitary wastewater needs a biological and disinfection route. Fabrication UPW blowdown needs separate treatment for its organic and fluorinated constituents. If the Comilla site has no fabrication operation, omit fab-specific fluoride, copper, TMAH and ZLD requirements from the preliminary design. The same segregation principle is applied in the Memphis data-center wastewater treatment comparison.
Choose a treatment train that matches the water source
The preliminary cooling-blowdown train should remove solids, control hardness and silica, protect membranes, control dissolved solids and disinfect the recovered water before return to the cooling loop. HydropureWater’s Chattogram guide, published in 2026, recommends multi-media filtration, softening, UF or equivalent membrane protection and brackish-water reverse osmosis for smaller installations. Its UF pretreatment for Comilla RO skids is relevant where source testing identifies suspended solids or colloidal fouling.
| Water source or objective | Preliminary treatment sequence | Key decision input |
|---|---|---|
| Cooling-blowdown reuse | Equalisation and side-stream filtration → hardness control → RO pretreatment where justified → RO or another dissolved-solids barrier → disinfection → conductivity-controlled return to the cooling loop | Measured blowdown flow, source chemistry, CoC and cooling-water compatibility |
| Sanitary wastewater | Package treatment or MBR followed by disinfection | Sanitary flow and effluent quality, not the cooling-blowdown peak |
| Treated-wastewater makeup | Seasonal characterisation, compatibility review, then filtration and site-specific polishing as required | Seasonal quality and effects on tower materials, membranes and biology |
| River-water makeup | Seasonal source testing followed by cooling-specific treatment | Availability, water quality, temperature and ecological effects |
| Remaining discharge | Treatment of temperature, residual oxidant, TDS, pH and suspended solids as consent requires | Comilla-specific consent; no verified Comilla numeric limits are supplied |
HydropureWater’s Chattogram guide states that conventional brackish-water RO on cooling-tower blowdown normally plateaus at 75–80% recovery before calcium carbonate, calcium sulfate and silica scaling dominate. That is a design constraint, not a Comilla performance guarantee. Evaluate the multi-media filtration stage, an industrial softener where hardness data supports it, and the industrial reverse osmosis system against the measured source-water profile.
For a sanitary route, size the biological or package system from the sanitary flow and load. For treated-wastewater or river-water makeup, first establish seasonal quality, then use pilot or supplier analysis to confirm compatibility with the cooling tower, membranes and treatment chemistry. Where discharge remains necessary, obtain the site’s actual consent before fixing temperature, oxidant, TDS, pH or solids targets.
Protect reuse water, membranes and cooling equipment
Automatic conductivity and pH control should define the blowdown and reuse loop because conductivity provides a direct indication of dissolved-solids accumulation. HydropureWater’s Chattogram guide identifies silica, hardness and conductivity as scaling constraints in the concentrate and recommends validating thresholds through makeup- and reject-water testing rather than adopting unverified site values.
UF is critical where iron-prone groundwater can foul membranes, according to HydropureWater’s Chattogram guide in 2026. Comilla source water must be tested before deciding whether UF is necessary. Its role is membrane protection: removing suspended solids and colloids before RO, not correcting every dissolved constituent.
For microbial control, the supplied Chattogram guidance identifies chlorine dioxide or UV. Verify residual-oxidant compatibility with membranes, seals and the cooling chemical programme before selecting either method. The chlorine dioxide generator option, automatic chemical dosing system and UV treatment option should therefore be evaluated as controlled process steps, not standalone guarantees of safe reuse.
Use automatic dosing for inhibitor, biocide and pH control. HydropureWater’s Chattogram guide notes that missed manual dosing can increase chemical cost, dissolved-solids loading and operating risk. Specify alarms, duty/standby pumps, calibration access and a clear chemical-safety interface with the cooling-water team.
The operating controls should cover conductivity, pH, flow, differential pressure, oxidant residual and chemical dosing status. RO recovery and concentrate quality need to be reviewed against membrane and scaling conditions during commissioning. If reuse is proposed, confirm the return point, maximum conductivity and chemistry limits with the chiller and cooling-tower operators before ordering equipment.
Plan sludge, monitoring and environmental safeguards
The liquid plant is incomplete without a solids and monitoring plan. Provide dewatering for backwash, softener regeneration and any RO-concentrate solids that are collected as sludge. HydropureWater’s product evidence confirms plate-and-frame presses from 1 m² to 500 m² filtration area, so the plate-and-frame filter press option should be specified from measured solids mass, sludge characteristics and the required handling route.
Document intake, discharge and reuse volumes. The supplied sources identify no mandatory Bangladesh data-centre water disclosure framework, while Climate Watch’s 2026 analysis presents voluntary transparency as a licence-to-operate measure. Keep records that distinguish source withdrawal, evaporation consumption, blowdown, recovered water and final discharge.
The Business Standard recommended in 2026 that project approvals include regular monitoring, enforceable water-use limits where necessary and drought contingency plans. It also advises assessment of local water stress, competing household and industrial demand, energy sources and ecosystem effects. Those checks should precede approval or expansion.
Where treated effluent is reused for cooling, toilet flushing or irrigation, verify each destination’s quality and public-health requirements. Do not infer approval from the general recommendation to reuse treated wastewater. Obtain Comilla-specific DoE consent, source permissions and acceptance of the proposed reuse or discharge route.
The industrial wastewater treatment procurement checklist provides a useful structure for the residual-disposal scope, but local sludge classification, transport and disposal conditions still require Comilla-specific confirmation.
Build a supplier RFQ that produces comparable proposals
A comparable RFQ requires every bidder to state the same design basis and exclusions. Require the design flow, source-water assumptions, cycles of concentration, recovery target, concentrate route, consumable use, control philosophy, monitoring scope, commissioning obligations and exclusions. The [data-center treatment guide for Nairobi](/blog/9831-data-center-wastewater-cooling-blowdown-treatment-in-nairobi-kenya-2026.html) can support the tender structure, but its site assumptions must not be transferred to Comilla.
| RFQ schedule | Information or deliverable required from each supplier | Approval check |
|---|---|---|
| Design basis | Measured flows, chemistry, CoC, recovery, utilities and operating envelope | Assumptions match Comilla source data |
| Water and mass balance | Makeup, evaporation, blowdown, product water, reject, sludge and final discharge | Inputs and outputs reconcile |
| Equipment scope | Pretreatment, softening, membrane treatment, disinfection, dosing, controls and sludge handling priced separately | No hidden exclusion or duplicate equipment |
| Civil and site works | Tanks, foundations, power, drainage, access and tie-ins | Site interface is defined |
| Commissioning | Factory acceptance testing, site testing, performance criteria and operator training | Acceptance tests are measurable |
| Commercial schedule | Manufacturing, freight, local installation, commissioning, spares and support | Delivery risk and local support are visible |
| Cost model | CAPEX, OPEX, replacement reserve, water value, disposal cost and disposal route | Uses actual Comilla tariffs and site costs |
Request evidence of factory acceptance testing on the offered configuration, South Asian reference installations, spare-parts support and a delivery programme broken into manufacturing, freight and local installation. Require each bidder to return the RFQ with unresolved assumptions identified rather than hidden inside a price.
The return-on-investment calculation must use the actual Comilla water tariff and avoided discharge or reuse value. The research supplies no defensible Comilla tariff or skid price, so require a site-specific calculation rather than importing a Chattogram benchmark. Obtain comparable installed costs, consumable consumption, membrane assumptions and disposal charges before comparing bids.
Frequently Asked Questions
How should cooling-blowdown treatment be sized for a Comilla data center?
Size the plant from measured cooling-water flow, makeup water, blowdown and cycles of concentration, not from the server load alone. HydropureWater’s 2026 Chattogram guide identifies a 15–30% uncertainty between theoretical and measured blowdown and gives blowdown as 1/(CoC−1). Confirm the design flow with operating logs, including emergency dumps, before setting equipment capacity.
Should cooling blowdown and sanitary wastewater use the same treatment plant?
No. Cooling blowdown is primarily an inorganic and oxidant-bearing stream, while sanitary wastewater requires biological treatment and disinfection. Fabrication wastewater may require a further distinct process because of its organic, fluorinated and metallised contaminants. Segregate the streams, then size each train from its own flow, chemistry and destination.
What should be obtained before approving a Comilla supplier’s quotation?
Obtain Comilla-specific source-water analysis, DoE consent, applicable water-source permissions, and written acceptance of the discharge or reuse route. The supplied research contains no verified Comilla groundwater profile, numeric discharge limits, water tariff or permit threshold. Do not use a Chattogram or Chattanooga figure as a substitute for those inputs.
How can procurement compare treatment suppliers on cost and delivery risk?
Require a complete water and mass balance, itemised CAPEX and OPEX, source-water assumptions, recovery target, concentrate route, factory-acceptance criteria, reference installations, local spares support and a delivery schedule separated into manufacturing, freight and installation. The cost case must use the actual Comilla water and disposal costs because the research provides no defensible Comilla skid price.
