Pulp and paper mill wastewater treatment using specially designed units in combination with electrocoagulation and low-cost ecofriendly materials

BACKGROUND AND OBJECTIVES: Industrial wastewater generated from manufacturing, processing, and chemical treatments contains a range of organic and inorganic pollutants that significantly deteriorate water quality. Conventional techniques, including chemical coagulation–flocculation and membrane filtration, while commonly employed, frequently encounter challenges when addressing complex and highly concentrated industrial effluents. Within this framework, electrocoagulation has appeared as a viable alternative technology. The key objective of the present study was to assess the efficacy of electrocoagulation combined with filtration, adsorption, and biomaterial-based treatment units in reducing the pollutant load of paper mill effluents.METHODS: Paper mill effluent was collected and subjected to electrocoagulation followed by multistage filtration using three different prototype designs. Physicochemical parameters and heavy metal concentrations were analysed before and after treatment. The metals assessed included chromium, copper, iron, nickel, zinc, manganese, and lead. The ionic composition of untreated and treated effluents was assessed using high-pressure ion chromatography. Three treatment unit designs were developed: Design ۱ comprised an electrocoagulation unit followed by adsorption and biomaterial-based filtration; Design ۲ incorporated electrocoagulation, adsorption, biological treatment, and ultraviolet disinfection using plastic containers mounted on a mild steel frame; and Design ۳ utilized glass units arranged on a mild steel stand to evaluate treatment efficiency under controlled conditions. Affordable biomaterials such as tea powder, bagasse, sawdust, wooden peels, coconut shell, and coconut husk were used as adsorbents.FINDINGS: The holistic treatment method revealed a considerable decrease in pollutant concentrations, including heavy metals and ionic species. Electrocoagulation destabilized colloids and facilitated metal removal, while biomaterials enhanced adsorption efficiency. Among the three designs, integrated systems demonstrated the most superior overall treatment performance. Overall, at ۳۰ minutes. electrocoagulation operation, iron-iron rods and iron-aluminium configurations showed the most stable and effective performance, achieving comparatively lower electrical conductivity (۱۴۱۱–۱۷۴۳ micro-Siemens), total dissolved solids (۹۰۵–۱۰۲۶ milligrams per liter), chemical oxygen demand (۵۱۴–۶۰۰ milligrams per liter), and hardness (۳۶۸–۴۸۰ milligrams per liter) than other electrode combinations.CONCLUSION: The study confirms that electrocoagulation combined with biomaterial-based filtration is an effective and cost-efficient option for treating industrial wastewater. The extensive application of this comprehensive method has the capacity to be more financially efficient than standard treatment systems.

کلیدواژه ها:

Ecofriendly Materials ، electrocoagulation ، Pulp and Paper Mill Effluent ، Specially Designed Units ، Wastewater treatment