Water Treatment.

The last few years during the rainy season I have had the privilege of working during the winter. I have been able to gain training on the same equipment used in filtering water for agriculture use. In agriculture orchards and fields the water might need to have salt or sand filtered out. The state of California has passed laws for construction builders to filter any outgoing water from a progressive construction site. While the roads are cut and no under ground piping is installed all water has to be filtered to under 15 NTU. When water is pumped off the site the water needs to be clear. Drinking water is less than 1NTU. So when it rains and the water is collected in holding ponds a biodegradable chemical called Chitosan is added to the water. Chitosan is made of shell fish, crabs and shrimp stuff. It run approximately $3500 Dollars for 250 gallons. Not Cheap stuff. It comes in liquid form. When added to the water it reacts to the dirt molecules and attaches itself to them causing them to sink. Water will come in looking like chocolate milk and after reacting to the polymer it leaves looking like cloudy water. After filtering through several holding pond the water is pushed through a sand media filter. This filter has to be run at thirty five pounds to be effective. The filters are in groups of four and have layers of crushed rock and sand in them for final filtration. These filters are identical to the agriculture filters. Only we use the filters to remove dirt and polymer out so the streams, rivers, lakes and eventually the delta doesn't fill up with silt. After the Sand media filters the water passes through the last stage of filters. In this stage we use bag filters that catch any dirt or polymer which slips through the first stage. After that the water is discharged clean into the nearby storm drain or creek. This year was the first time I was able to oversee to set up of the system. I was able to get a closer idea of how things worked and how much water we process. This year we are set up to process and filter 1200 Gallons every minute. That seems like a lot of water, but when thirty acres of rain water is funnel to one spot it can become a problem. When it rains I'll be out pumping water day and night.