Makeup Water Treatment
Sheppard T. Powell Associates LLC (STPA) has considerable experience in the planning, design, operation and evaluation of various types of makeup water treatment facilities. For the Electric Power Research Institute (EPRI), STPA authored the Guidelines for Makeup Water Treatment (GS-6699, 1990), the Revised Guidelines for Makeup Water Treatment (TR-113692, 1999) and the membrane filtration and Reverse Osmosis (RO) sections of the Guidelines for Makeup Water Treatment-Conventional Fossil and Heat Recovery Steam Generator Water/Steam Cycle Makeup (TR-1019635, 2010) for EPRI.
Water Requirements and Sources and Reuse Options
STPA has provided consultation for defining the quality and quantity of makeup water to power boilers, recovery boilers, HRSGs, cooling tower systems, service water systems, closed cooling water systems, and open cooling water systems. Included in the quantity determination are the onsite water storage requirements. STPA has experience with surface water, groundwater, municipal water, wastewater, and recycled water for raw water supply to a facility. STPA has evaluated reuse waters and water management options and constructed and reviewed water balances.
Based on the characteristics of the water supply and product water quality, a treatability study evaluates the unit processes required to treat the water supply. For new facilities, one may evaluate various water supplies or reuse waters (raw water, blowdown, treated wastewater, evaporator distillate). For existing facilities, a study can determine if a new treatment system is required or if modifications can be made to the existing water treatment system. STPA can provide the conceptual design for new or replacement systems. Also, the study may include biological control options.
Pretreatment: Clarification and Filtration
STPA has evaluated the design and operation and helped troubleshoot pretreatment systems for removing suspended solids, colloidal solids, organics, color, iron, manganese, and hardness (chemical softening). These have included filtration systems containing sand filters, gravity filters, pressurized filters, multimedia filters, carbon filters, microfilters and ultrafilters.
Demineralization and Degasification
STPA has performed in-depth evaluations of the design, operation and troubleshooting of makeup demineralization systems using various forms of ion exchange (softening, organic traps, strong acid and weak acid cation and strong and weak base anion exchange, mixed-bed), degasification (decarbonator or membrane degasifier), reverse osmosis (RO) membrane demineralization, and continuous electrodeionization (CEDI).
STPA has developed chemistry manuals with control limits and response procedures for pretreatment, filtration, demineralization and degasification equipment. STPA has conducted training seminars, treatment and surveillance audits and chemistry reviews of makeup water treatment systems for utility and industrial facilities.