Quality of effluents from Hattar Industrial Estate

Of 6634 registered industries in Pakistan, 1228 are considered to be highly polluting. The major industries include textile, pharmaceutical, chemicals (organic and inorganic), food industries, ceramics, steel, oil mills and leather tanning which spread all over four provinces, with the larger number located in Sindh and Punjab, with smaller number in North Western Frontier Province (NWFP) and Baluchistan. Hattar Industrial Estate extending over 700 acres located in Haripur district of NWFP is a new industrial estate, which has been developed with proper planning for management of industrial effluents. The major industries located in Hattar are ghee industry, chemical (sulfuric acid, synthetic fiber) industry, textile industry and pharmaceuticals industry. These industries, although developed with proper planning are discharging their effluents in the nearby natural drains and ulti- mately collected in a big drain near Wah. The farmers in the vicinity are using these effluents for growing vegetables and cereal crops due to shortage of water. In view of this discussion, there is a dire need to determine if these effluents are hazardous for soil and plant growth. So, effluents from different industries, sewage and normal tap water samples were collected and analysed for pH, electrical conductivity (EC), total soluble salts (TSS), biological oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen, cations and anions and heavy metals. The effluents of ghee and textile industries are highly alkaline. EC and TSS loads of ghee and textile industries are also above the National Environmental Quality Standards (NEQS), Pakistan. All the effluents had residual sodium carbonates (RSCs), carbonates and bicarbonates in amounts that cannot be used for irrigation. Total toxic metals load in all the effluents is also above the limit i.e. 2.0 mg/L. Copper in effluents of textile and sewage, manganese in ghee industry effluents and iron contents in all the effluents were higher than NEQS. BOD and COD values of all the industries are also above the NEQS. On the whole, these effluents cannot be used for irrigation without proper treatment otherwise that may cause toxicity to soil, plants and animals as well add to the problems of salinity and sododicity. Similarly, these effluents cannot be used for fish farming.

Effect and Cost Research for Leachate Treatment in PAC/Fenton and Fenton/PAC Technology

To compare the treatment effects and the costs of coagulation/Fenton process and Fenton/coagulation process in leachate treatment,fresh and old leachates were respestively treated with these two techniques.The experimental results indicate that the highest chemical oxygen demand(COD)removal rate of Fenton reaction on leachate can be acquired under the conditions of pH=3.5,nH2O2/nFe2+=6,mH2O2/mCOD=3,and reaction time=4 h.Polyaluminium chloride(PAC)coagulation has the highest COD removal rate on leachate under the condition of mPAC/mCOD=0.6.Under the optimum reaction conditions,coagulation/Fenton and Fenton/coagulation processes were respestively adopted to treat raw leachate.The data also show that COD removal rate of coagulation/Fenton process on fresh and old leachates are 90.56% and 86.52% respectively and that of Fenton/coagulation process 89.99% and 85.99%,so there is no obvious difference.But the cost of coagulation/Fenton process for leachate treatment is RMB 62.6,lower than that of Fenton/coagulation process.Therefore,coagulation/Fenton process is more optimized than Fenton/coagulation process for leachate treatment.