The hydrodemolition wastewater contains suspended particles (ranging up to 15,000-ppm total suspended solids [TSS]) and typically has a pH of 11 to 12.5. Treating the wastewater is typically a two-step process. First, reduce the TSS to an acceptable level followed by adjusting the pH to within an acceptable range.
The question always is: What is an “acceptable” range? The answer to this question will depend on the local regulations for wastewater discharge. If discharging into a sanitary sewer, the discharge restrictions may be 300 ppm of TSS with a pH in the range of 6-12 (very lenient). If discharge will take place on site directly to the ground, the restrictions may be a Turbidity of <50 and a pH of 6 ½-8 ½ (NYSDOT). Regardless, hydrodemolition wastewater will need to be collected and treated.
Rampart offers two levels of treatment depending on the local requirements. Our most environmentally sensitive system is our Automated Vacuum-Filtration System (AVS®). This unit can filter the wastewater to 1 micron using diatomaceous earth (similar to a swimming pool filter only much larger). This filtration will reduce TSS to <20 and Turbidity to <50 (typically around 10). Following the removal of the suspended solids, the water is further treated with CO2 to reduce the pH to 6-9. This water appears as clear as drinking water. This water meets NYSDOT’s requirements for land discharge.
In areas where there is access to a sanitary sewer, the treatment requirements may not be as strict as the water will be further processed at the treatment plant. Often the TSS requirements are in the range of 250 to 400 with pH requirement of between 5 and 12. Depending on the municipality, the range can often be 6-10 or even 6-9. In any event, this requirement is significantly more easily accomplished. To achieve this level of treatment it may only be necessary to settle the water in retention basins followed by some additional filtration and then treatment to reduce the pH. Rampart can provide a system of tanks and filters along with pH adjusting equipment to meet these requirements.
After many successful projects, we are able to either assist you in performing the hydrodemolition wastewater treatment or perform the service for your project.