BCHOD's name has been synonymous with wastewater treatment throughout the region for nearly 70 years with well over 100 projects in more recent times.
Types of works and processes designed and constructed under BCHOD supervision have included:
Conventional works, incorporated Screens, grit channels, comminutors, primary sedimentation tanks, biological filters, humus settlement tanks, slow sand filters, chlorination and secondary digesters and sludge drying beds.
Modified activated sludge treatment works including aeration, primary settlement tanks, clarifiers, sludge digesters, sludge thickeners and all related machinery and controls.
Wastewater treatment Systems for industrial, commercial and mining clients that have ranged in size from a few cubic meters of raw sewage per day to more than 70ML/day.
Pond systems incorporating facultative and maturation oxidation ponds with the inclusion in many facilities of additional facilities like anaerobic pre-treatment, effluent re-cycling and sludge disposal.
BCHOD pioneered the use of oxidation ponds and anaerobic treatment for wastewater in the Central African Region. The firm designed the first large-scale anaerobic/aerobic ponds system [including effluent recirculation] of its type in Zimbabwe for the City of Harare at Mabvuku. The anaerobic part of this design was later adopted with a conventional works design at Zengeza by the City of Harare.
In the mid-70's the firm designed one of the first modified activated sludge sewage treatment facilities at Gaths Mine, Mashava, from which effluent was reclaimed for use in the Mill. This necessitated partial nutrient removal and effluent very low in solids content. The type of sewage treatment installed has often depended upon the availability of land, whether effluent reclamation would be required, and the degree of expertise needed for operation. Generally, therefore, the various forms of wastewater treatment available in the country has been explored and reported to our clients with recommendations, designs and construction implementation.