Water purification installation for rainwater harvesting system
Many properties in Southern Africa face intermittent water supply problems. The problem can be overcome by installing a backup water system. Our design engineers have taken it one step further; we design and install a rainwater harvesting systems and integrate it with a backup water system.Thus during periods of rainfall the property will use rainwater as a main water supply and during periods of low rainfall the system will be converted to a backup water system, thus ensuring the property has a supply of water at all time, even during water supply interruptions. The rainwater storage tanks are then used as backup water storage and our engineers can set the amount of water that can be stored in the system. leaving sufficient capacity for recovery of rainwater should it start raining again.
At the heart of this type of system is our potable rainwater purification unit as seen below:
Our team recently installed one of these system at a residential property in Hillcrest, Durban. The unit is contained within a stainless steel frame. Our engineers have designed it to easily integrate with solar inverter system and it only consumes 0.37Kw of electrical energy while pumping. The 24L pressure tanks and controller prevents frequent stop/starts which further optimizes energy consumption. Our company manufacture theses units and also sell them to a number of installation companies. We also export these unit to some of the Indian ocean islands where rainwater harvesting is an integral part of many proprieties.
Backup water system design and installation in Durban
We recently designed and installed a system at a residence in Westville Durban.The system consists of 3 interconnected 1000l water tanks that is connected to the municipal water . The level is controlled by a solenoid float valve. A multistage centrifugal pump draws water from the tank and pumps the water to the house. The pump maintains pressure to the premises. As long as there is water in the tank the premises will have adequate water pressure. The system does not work during load-shedding, thus we installed an automatic bypass system using solenoid valves at the municipal supply point. Should the power fail the system will automatically revert back to direct municipal supply, bypassing the tanks, when the power is restored the system reverts back to normal operational mode.
Read more: Backup water system design and installation in Durban
Sustainable rainwater harvesting for Ethiopian Industrial Parks
The Tizagenix team was contracted by IDH sustainable trade to develop conceptual and sustainable rainwater harvesting solutions for two industrial parks in Ethiopia. The two parks are situated in Kombolcha and Hawassa and are home to their textile manufacturing facilities and employ in excess of 35000 people.
- Kombolcha Industrial Park is situated just outside Kombolcha next to the local airport. Constructed in 2016/17 the park is situated on 75ha of land. Total area of sheds and auxiliary buildings are 6.75ha, site hard surface area is 40.25Ha, greenery area is 21Ha and developed land for future expansion of 2 Ha. The parks’ only source of water comes from boreholes that supply the total water demand in the park. In Kombolcha region 67% of the rain occur in July and August.
- Hawassa Industrial Park is was constructed in 2015/16. The park is situated on 140 Ha of land. Total area of sheds and auxiliary buildings are 34Ha, site hard surface (roads/walkways) area approximately 78Ha and greenery and other areas are approximately 28Ha. The parks’ only source of water comes from boreholes that supply the total water demand in the park. The park has net zero liquid discharge industrial and sewerage treatment plant with a capacity of 11 000 m3 per day.
The objective of the team was develop rainwater harvesting solutions for both parks in order to reduce borehole water consumption and reduce the environmental impact that these parks have on the local environment.
In order to do the concepts development our team had to visit and evaluate all aspects of water use and demand in the industrial parks. We evaluated the average rainfall and rain intensity for each park, as well as various models and data from the available weather statistics and research reports. In the evaluation, all potential surfaces where rainwater could be harvested during a rainfall event was evaluated,as well as possible water quality generated from these surfaces during a rainfall event. Or team did volume calculations of water during a rainfall events, considering maximum rainfall intensities to calculate possible worst-case scenarios.
Based on the information various flow models were developed to balance water harvested during the rainfall events with the processing and storage of rainwater. This information was used to develop concepts, flow diagrams, sizing and costs of the recommended systems.
Our team developed concepts designs and costed the projects which will significantly reduce the use of borehole water as well reduce the discharge of storm water into the natural environment.
Rainwater Harvesting assessment for logistics group Gauteng
Our team was requested by an environmental consulting group, to do a large-scale rainwater harvesting project concept and feasibility analysis for a major logistics group in Gauteng, South Africa.
The primary objective of the assessment was to look at reducing the monthly water consumption of the facility, reduce their operational risk of water interruptions and to realize financial benefits that a water saving initiatives can provide.
Our assessment investigated rainwater harvesting from approximately 75 000 square meter of warehouse roof and using the rainwater that fall on the premises to offset the operational water consumption of the site.
Our assessment indicated that the facility had sufficient surface area on site to recover rainwater for the total water requirement for the premises. However due to the rainfall patterns in Gauteng, a few rain days with high intensity rain, when it rains (see historic rainfall pattern below), the system priority will be to recover water as best as possible and then store it for periods with low rainfall as indicated on the rainfall pattern chart.
We developed two mega rainwater harvesting system concepts designs for the client that:
- Evaluated rainwater recovery opportunity.
- Identified the most suitable surface area and method for effective rainwater recovery, based on climatic data for the area.
- Identified the potential water volume recovery for each application.
- Made recommendations to ensure minimal contamination of recovered water.
- Identified a rainwater storage solution to maximize the opportunity up supply.
- Supplied a water usage assessment specific for the building occupation and the use of rainwater.
- Pre-determined the water quality together with a risk assessment to minimize possible contamination.
- Conducted a conceptual risk assessment for the use of rainwater within the building
- Identify the size and opportunity and potential return on investment that exists for the proposed installation.
Our engineering team recommended a concept with potential savings of more than R1 million per year and a ROI of less that 10, with a system that will ensure effective quality water supply to the premises at all times, irrespective if the municipal water supply to the site.
Backup water systems at KZN South Coast
The KwaZulu Natal South Coast and in particular the UGU district is plagued with constant water interruptions due to the municipalities' inability to supply a reliable source of water. Many holiday homes and complexes have experienced reduced occupancy at peak season due to the water problem. We have done a number of backup water system at holiday homes and complexes to assist the owners to overcome the problem.
We have recently installed system that would also function during load shedding. During load shedding when the pressure pump cannot function the system automatically switches over to municipal water supply (that is if there is municipal water), and some systems are able to at least gravity feed water to the property during this period until power is restored. When the power comes back on, the direct online municipal supply automatically close and the system reverts to normal pump pressure operation.
Various backup system options exist. In some systems we install submersible pressure pump with pressure controllers. These systems are very quite and the only visible part of the system is a tank.
