Huaihua Wangda Biotechnology Upgrades Pharmaceutical Intermediate Wastewater Treatment with a 4 m³/h Fenton Oxidation System

Huaihua Wangda Biotechnology Co., Ltd. operates a pharmaceutical intermediate plant in Huaihua, Hunan Province, with an annual output of 1,800 tonnes. The site's existing environmental protection facilities needed an upgrade to keep pace with production, and Baihuipu was contracted to supply the upgraded wastewater treatment system. The design capacity is 4 m³/h, treating two distinct streams from the production area: high-concentration mother liquor and general wastewater.

Project Background

Pharmaceutical intermediate production generates two very different effluents. The mother liquor from synthesis and separation steps carries a high organic load and is the stream that sets the treatment philosophy. The remaining general wastewater — equipment washing, floor washing and dilute process water — is larger in volume but milder in concentration. Treating both in a single train would either over-design the biological route or under-treat the mother liquor, so the upgraded system keeps the two streams separate from storage through to sludge handling. The same stream-segregation logic is applied across our chemical and pharmaceutical wastewater treatment projects.

Treatment Process: Two Fenton Lines

The core of the upgrade is a pair of integrated Fenton oxidation units:

Mother liquor line: the M105 mother liquor storage tank feeds an integrated Fenton unit dosed with ferrous sulfate, sulfuric acid, hydrogen peroxide, alkali, PAC and PAM. Oxidized liquor is pumped to a 30 m³ oxidation liquor tank. Sludge settled from the Fenton reaction is pumped to the mother liquor sludge tank, then dewatered by the mother liquor filter press, with filtrate returned to the filtrate tank.

General wastewater line: general wastewater is stored in its own tank and treated in a second integrated Fenton unit with the same reagent set, then passes to a denitrification membrane system for nitrogen control. Its sludge reports to the same sludge tank and filter press train.

Why Fenton for Pharmaceutical Intermediates

Pharmaceutical intermediate effluent contains refractory organics that biological systems struggle to degrade on their own. Fenton oxidation (ferrous sulfate + hydrogen peroxide) generates hydroxyl radicals that break these molecules into smaller, biodegradable fragments, while the downstream PAC and PAM dosing flocculates the reaction products into a settleable sludge. The result is a pre-treated stream that is stable enough for further treatment and compliant discharge. For sites where the concentrate ultimately needs zero liquid discharge, the same oxidation front end pairs naturally with evaporation, as set out in our zero liquid discharge solution for industrial effluent.

Equipment Supplied

The system delivered to Huaihua Wangda includes:

Two integrated Fenton oxidation units with covered PP reaction tanks and agitators; chemical storage and dosing skids for ferrous sulfate, sulfuric acid, hydrogen peroxide, alkali, PAC and PAM; an M105 mother liquor storage tank and a 30 m³ oxidation liquor tank; a denitrification membrane system on the general wastewater line; sludge tanks, filter presses and filtrate return for both lines; and a control system with an explosion-proof cabinet at the treatment area, reflecting the hazardous-area classification of a pharmaceutical intermediate plant.

Sludge Dewatering

Both Fenton lines produce chemical sludge, which is concentrated in the sludge tanks and dewatered by filter press. The dewatered cake leaves site as regulated solid waste, and the filtrate returns to the treatment front end so nothing is lost. This closed sludge loop is standard across our chemical-industry projects and keeps the operator's disposal volume to a minimum.

Scope and Cooperation

Baihuipu's scope covered process design for the two-stream flowsheet, fabrication of the integrated Fenton units, dosing systems and tanks, delivery to site in Hunan, installation guidance, commissioning and operator training. The upgrade was executed while the plant continued production, so the new units were tied in without interrupting the existing line. Where pharmaceutical sites also run high-salinity concentrate streams, we often combine this kind of oxidation front end with evaporation, as described in our MVR evaporator systems for high-salinity industrial wastewater.

Why Choose Baihuipu as Your Manufacturer

Own factory: all tanks, skids and control panels are fabricated in our Guangdong facility, so material grades and delivery dates are under our direct control.

Industry experience: more than twenty years building wastewater treatment equipment for pharmaceutical, chemical, electroplating, food and municipal clients, with projects exported to over twenty countries.

Complete system responsibility: process, mechanical, electrical and controls engineering are handled in-house — one supplier carries the process guarantee from screening through to sludge dewatering.

After-sales support: spare parts, remote diagnostics and on-site commissioning and training are part of every supply.

If your pharmaceutical or chemical plant needs an upgrade of its existing treatment facilities, share your water analysis and site constraints and our engineers will propose a practical process route. Contact us at WhatsApp: +86 13631765076 or visit hkbhp.com.

Frequently Asked Questions

Why keep the mother liquor and general wastewater streams separate?

The mother liquor has a far higher organic load and needs a heavier oxidation dose. Mixing it with general wastewater inflates the size of every downstream unit; keeping the streams separate lets each line be sized and dosed economically.

What does a Fenton system need to run day to day?

Mainly chemical replenishment (ferrous sulfate, sulfuric acid, hydrogen peroxide, alkali, PAC, PAM), routine sampling of pH and ORP, and periodic sludge discharge to the filter press. Dosing is automated through the control system.

Can the denitrification membrane system be added later?

Yes, if space and pipe connections are planned at the design stage. We recommend telling us about any nitrogen-limit consent up front so the general wastewater line can be laid out for it from the start.