Gujarat Agrochem Limited

Operating on an incoming TDS of 70,000 ppm and 20,000 ppm COD, this is the first installation of a bio-remediation system on Agro-Chemical industry effluent.
  Overview of the Company:

  • Gujarat Agrochem Ltd is a group company of Tagros Chemical Group based at Chennai.
  • The group is one of the leading groups in the field of Agro chemicals. The company is manufacturing different agrochemicals, pesticides, herbicides etc.
  • The company has world class manufacturing facilities at Panoli, Dahej and Chennai. The company is in the export business of chemicals.

  Inlet Effluent Detail:

  • pH : 4.5 to 13.5
  • TDS : App 70000 ppm
  • COD : App 25000
  • NH3-N : Around 300 ppm

Objective of Treatment:

  • To neutralize the pH of effluent without any chemical addition
  • To evaporate the effluent and achieve Zero Liquid discharge system
  • To reduce the TDS sludge from the system

  Before Applying the Algae Technology: The Client operates a MEE at site. High TDS and high COD effluent containing solvents is directly fed into the MEE. The operating cost of MEE inclusive of sludge handling is upwards of Rs. 2000 / M3. We have successfully setup and demonstrated for a 0.5 kL/day capacity. We are now setting up a 10 kL/day capacity plant which will then be scaled up to a 150 kL/day capacity plant. After Applying the Algae Technology: We are in the process of commissioning a 5 kLD plant for Zero Liquid Discharge.

  1. Evaporation Rate:
  • The evaporation rate depends on several environmental factors i.e. temperature, wind velocity, humidity etc. In the present study, water loss is achieved through evaporation controlled by natural environmental factors along with transpiration by algae which are less dependent on natural environmental factors. The ideal evaporation rate in single layer with natural environmental conditions is around 3-4 mm /day and with microalgae is 10 mm/day.
  • Here, we planned to set up three layer evaporation roof in which we were expecting evaporation of 10 mm on top layer and 6-7 mm on both middle and bottom layer because it is not in contact with direct sunlight. According to these values, the expected evaporation should have been of [215 L + 148 L +150 L] = 513 L /day.
  • However, from the above data we can observe that an average evapo-transpiration rate of 700-800 L/64.36 sq. mt. / day achieved in the existing set up. The value is about 30-40 % higher than what the expectation was.

  2. TDS Sludge Reduction :

  • One of our major objectives was to reduc
  • e the load of TDS which is at present generated in MEE due to high TDS effluent evaporated through MEE.
  • TDS Theoretical: Theoretical TDS is the ideal value of TDS that should be in the process tank. In the control condition, where algae is not present, TDS should keep on concentrating as it remains in the tank itself as we are not discharging any effluent out of the loop. Theoretical value of TDS is what should be there in process tank if no treatment process is adopted.
  • Actual TDS: Actual TDS is the value of TDS which is measured experimentally in the Lab. It is clearly shown from the above graph that the actual TDS value which is experimentally measured from the tank is very low compared to theoretical value of TDS. This shows that significant amount of TDS is eliminated using the microalgae..
  • As of 28th May, 2016, the theoretical value of TDS should be 2, 45,770 ppm in the tank if we would not have adopted Algae Treatment. But, the actual value of the TDS was 57,700 ppm in the algae reaction tank which clearly shows reduction of TDS by Phycoremediation Technology.
  • As of 28th May, 2016, approx. 2535 kg of TDS is added in the algae reaction tank but at present only 595 kg TDS is remaining in the tank. i.e. App. 77% TDS is removed by Phycoremediation technology.

The significant change in the TDS removal was observed due to several factors i.e. metabolism, bioaccumulation, biotransformation, bio sorption and phycovolatilization through Microalgae in the effluent treatment process.

  • Reduction in NH3-N
  • Nitrogen is the major component of NH3-N. As nitrogen is a primary source for the growth of algae, it reduces Ammonical nitrogen very efficiently for the synthesis of protein and biomass.
  • The data shows that the theoretical value of NH3-N is keeping on increasing as we are not discharging the effluent but actual value of NH3-N is very low in the tank.
  • From the above data, we can observe that as of 28th May, 2016. Theoretical value of NH3-N was 1295 ppm while the actual value of NH3-N is 0 ppm. Above graph indicates that microalgae are completely utilizing the NH3-N present in the effluent.
  • Till now, total 13.4 Kg load of NH3-N is added in the tank but at present actual load of NH3-N is nil in process tank.

Above results shows that around 100 % NH3-N is consumed by Microalgae.

  • COD Reduction
  • The Phycoremediation Technology is also effective in the reduction of COD.
  • The data shows that the value of theoretical COD keep on increasing continuously since we are not discharging treated effluent. However, significant reduction in COD is observed.
  • We can observe that at as of 28th May, 2016 theoretical value of COD should be 96,174 ppm. However, the actual value of COD at present in the tank is 32,739ppm. This shows a significant reduction in COD in spite of having very high TDS effluent which contains solvents like toluene.
  • As of 28th May, 2016, total COD load added in the tank is 992 kg. However, actual COD load remaining in the tank is 337 kg., i.e. 655 kg of COD is reduced which is around 66% amount of total load added.
  • pH Correction :
  • The pH of the effluent after mixing of 3 different streams was in the range from (4.5-12.9).
  • However, pH of the process tank was corrected and maintained in the range from 8 to 9 throughout the process. It’s due to peculiar characteristics of algae that it increases the pH of medium towards alkaline condition.
  • This is the additional benefit which can eliminate the cost of chemical utilization for pH neutralization.