Ro Application case study

Synopsis
Pure water in manufacturing industry is a necessity, however, with the growing focus on sustainability and circular economy, industries and governments are moving towards ZLD ( Zero Liquid Discharge). To practice it in letter and spirit the industry needs to find an energy efficient way to recycle water and make it fit enough to be used back in the manufacturing process. In India, industries widely use Reverse Osmosis (RO) technology for treating brackish water and industrial treated effluent. However, the water reject, generated during the RO process is a major environmental concern. The rejected water contains high levels of Total Dissolved Solids (TDS) and other impurities, making it unsuitable for discharge back into the environment. LiquidSky developed an innovative solution to treat the RO reject water and convert it into clean water, fit for reuse in the industrial processes.

Background
Government of India is keen on implementing Zero Liquid Policy, under which water in any form. cannot be drained out from the industry. Even the RO reject that was earlier used in gardening and housekeeping, needs to be recycled and reused in industrial processes. Industries needed an energy efficient way to recycle RO reject water, to reduce the environmental impact caused by RO process. It also had to have low noise levels. Diverse sectors have an RO reject between 30% to 50% So, Liquid Sky had to develop a solution that was widely applicable to various sectore, irrespective of their RO reject percentage. A large industrial client was facing challenges in treating RO reject water generated from their manufacturing process. The client was using RO technology to treat their effluent,however, the rejected water generated during the RO process was unfit for reuse and was an environmental threat.

Process

Liquid Sky undertook a series of tests on the RO reject water, to understand the impurity levels. We explored various solutions that can improve the clean water output to permissible levels, to be reused in the industry processes.

No	Parameter	Feed Water	Distillate	Residue
1	PH	9	6.5	6.5
2	Conductivity	1896 µS/cm	6 µS/cm	30000 µS/cm
3	Chloride	138 mg/lit	nil	8000 mg/lit

Solutions:
Liquid Sky developed an innovative solution that combined various technologies, including Reverse Osmosis, Evaporation, and Crystallization. The treatment process involved the following steps:

Pre-treatment: The effluent water was first treated with a series of pre-treatment steps, including filtration, pH adjustment, and chemical dosing. This helped remove suspended solids, organic matter, and other impurities from the effluent.

Reverse Osmosis: The pre-treated effluent water was then treated with a two-stage RO system, which helped remove up to 95% of the TDS from the water.

Evaporation: The RO reject obtained from the second-stage RO system was then subjected to a mechanical evaporation process. This helped concentrate the remaining TDS in the water to a higher level.

Crystallization: The concentrated brine obtained from the evaporation process was then subjected to a crystallization process. This helped convert the remaining TDS into a crystalline form, which could be easily separated from the water. Discharge: The treated water obtained from the process was of high quality and suitable for reuse. The crystalline salts obtained from the process were disposed of in an environmentally friendly manner.

Results: 1. This application on RO reject water is one of the firsts in the country. The promising results encouraged more companies to consider our solution for RO reject water. Companies like Cummins Kothrud, Sandvik Asia Bopodi, and Seco Tools Shikrapur have implemented this MVR-based ZLD technology to achieve the MPCB (Maharashtra Pollution Control Board) consent and also to become wastewater free companies.

2. The treated water obtained from the process had a TDS level of less than 50 mg/L, making it suitable for reuse in the industrial process.

3. The solution provided by LiquidSky helped these customers reduce their freshwater consumption by up to 90%, resulting in significant cost savings.

4. The solution provided a cost-effective and environmentally friendly way to treat RO reject water and convert it into usable water, helping businesses be self-sufficient in their water needs.

5. An added advantage is the noise levels of the process. The noise levels fall within the permissible limits and hence it is a preferred solution for a mechanical industry operating in residential zone.

LiquidSky has successfully installed the RO reject application solution for industries like food processing, metal cutting solutions and engine manufacturers with consistent and measurable success.