A residential district plans to build five new 28-storey houses with 827 households in the near future, with a total population of 3 105 and a total construction area of about 120000 square meters. Use municipal tap water as water source. According to the first paragraph of the Notice on Strengthening the Management of Reclaimed Water Facilities.
Item (3) requires the construction of reclaimed water facilities. Based on the stipulation that reclaimed water facilities must be designed, constructed and used simultaneously with the main project, reclaimed water facilities are designed.
Second, the main problems considered in the design
(1) All newly-built houses should be equipped with 6L two-stage water-saving sanitary toilets, and the faucet should be water-saving.
(2) Quality drainage and quality water supply.
Separate drainage: fecal sewage and kitchen water are discharged separately, and then discharged into septic tanks and municipal sewage systems. Bath water and laundry water are discharged separately and collected as the source of reclaimed water. Water supply by quality: the house is equipped with reclaimed water supply system for flushing toilets.
(3) Centralized construction of reclaimed water treatment stations.
Third, the calculation of water consumption
(1) The maximum daily water consumption standard for residents is160 l/person/day, and the total population is 3 10 5.
Water consumption = 3105×160 = 496800l/day, and 500m3/ day is taken.
(2) The water consumption for greening is 4L/m2/ day, and the greening area is 4700m2.
Water consumption = 4×4700 = 18800 l/ day, taking 19 m3// day.
(3) Water consumption for car washing is 10L// every time, and car washing is 100 vehicles every day.
Water consumption =10×100 =1000l/day = 1 m3/ day.
Total water consumption = 500+ 19+ 1 = 520 m3/ day.
(4) According to Code for Design of Reclaimed Water in Buildings, the following calculation is made:
Maximum daily total indoor water consumption =500m3.
Bathroom water consumption 32% = 500×32% = 160 m3/ day.
Water consumption of kitchen is 23% = 500× 23% =115m3/day.
Recyclable water quantity = 500-160-115 = 225m3/day.
The hourly water treatment capacity of Zhongshui Station is 225/24, which is about 65438+ 100 m3/ hour.
Regulating pool of reclaimed water station = 225× 40% = 90m3.
Water storage tank of Zhongshui Station = 225× 30%, about 80m3.
Water consumption of facilities =225× 15=34m3.
(5) Water balance
The treated water is used for car washing, greening and washing indoor toilets.
225m3 of treated water can be collected.
The water consumption for flushing toilets is 160+ car washing/ton and greening water consumption.
19+ consumption 34=2 14m3
The basic balance is slightly abundant.
Four. Reclaimed water treatment process
Raw water-grid-pre-aeration regulating tank-lift pump-hair filter-biochemical sedimentation and filtration integrated equipment
-Dosing and disinfection reaction tank-intermediate water tank-water supply pump group
Sludge disposal: Sludge is digested in digester (standard septic tank) and used in agriculture.
Intake water quality: this project collects high-quality miscellaneous drainage in the house, with BOD5: 70 ~120mg/L and SS: 50 ~ 90mg/L. ..
Effluent quality: meets the requirements of building reclaimed water specification.
Five, equipment selection
(1) Automatic fine mesh.
Reduce labor intensity, improve efficiency and choose electrical equipment.
(2) Aeration regulating tank, 90m3, 1, concrete.
The regulating volume of the regulating tank is calculated as 35% ~ 50% of the daily treated water.
(3) The comprehensive water treatment equipment is 10 ton/hour.
Patented product, model: WHCZ-I- 10, the equipment is suitable for a wide range of raw water, bo D5:50 ~ 200mg/L, installed.
Divided into left and right groups, each group consists of biological contact oxidation tank, inclined plate sedimentation tank, multi-grid double-layer filter material tank and related equipment groups.
Integration, with the following characteristics:
Biological contact oxidation adopts high-efficiency new packing, which has large effective surface area, high load capacity and long service life; Oxidation tank oxygenation
Adopt a new type of high-efficiency jet aerator, with large air intake, low working pressure, low noise and less equipment occupation; Japanese quotation is adopted.
Low noise rotary fan, low energy consumption and treatment cost; Double-layer filter material is adopted, which has strong pollution interception ability and its filter can be divided into grids.
Mutual backwashing saves special backwashing pumps, water tanks and other facilities, simplifying the process; Flexible operation, both sides of the device
Can run at the same time, can backup each other, can realize non-stop water maintenance, and can also run only one group when the water saving is small.
Operating expenses; When the concentration of organic matter in raw water is high, two groups can be connected in series to form secondary water according to the requirements of Code for Design of Reclaimed Water.
Physical operation.
(4) Raw water lift pumps, 50GW-20-7, 2 sets, 1 service 1 standby, flow 1 1t/h, lift 10m, power 0.75k
Watt.
(5) hair filter.
Upflow XM hair filter is better than ordinary one.
(6) Low noise rotary blowers, 4 sets, 3 for use 1 standby.
(7) Two automatic dosing metering pumps, one for use and one for standby, with a power of 370W W..
Adding sodium hypochlorite liquid, sodium hypochlorite can be sold in the market, and the source is convenient and safe.
(8) The middle pool is 80m3, made of concrete.
The regulated water quantity is calculated as 25% ~ 35% of the daily water consumption.
(9) Frequency conversion feedback pumps, 80DL50-20X6, 2 sets, 1 service 1 standby, with a flow of 50 tons/hour, a lift 120m and a power of 30,000.
Watt.
(10) A water meter is set on the tap water supply pipe of the metering device, and a water meter is set on the treated reclaimed water supply pipe.
Description of the production process of intransitive verbs
The domestic high-quality miscellaneous drainage water is collected by the pipeline, enters the reclaimed water treatment station, and is balanced in the regulating tank after being removed by the grid.
Pre-aerate the water quality and quantity to prevent the sewage from rotting and stinking, and remove the solubility and part of colloidal organic matter in the water through aerobic contact oxidation.
In the material, more than 90% of BOD5 and more than 85% of COD are composed of microorganisms attached to the filler and growing in suspension, which pass through biological oxygen.
Chemical, synthetic, adsorption removal, microorganisms falling off the filler are removed by precipitation, discharged as excess sludge, and then passed through
The residual suspended solids (SS) in the precipitation water were further removed by filtration, and the filtered water was disinfected with chlorine to obtain qualified products.
regenerated water
Seven, problems that should be paid attention to in the design.
(1) First, determine the treatment water volume and the scale of the treatment station according to the requirements of design specifications.
(2) Because the height of the story often becomes the limiting factor in the design of reclaimed water station, the process design and elevation design are generally carried out at the same time.
All right.
(3) According to the height of indoor space, determine the elevation of structures, and there should be 7 00 ~ 900 mm space above the pool.
(4) The effective depth of the pool is the actual depth of the pool minus the upper protective height and the dead water area at the bottom. If there is a puddle, it can be exempted.
Dead water area
(5) The effective water depth of the regulating pool should be lower than the pipe bottom elevation of the inlet pipe. If the height below the pipe bottom of the lead-in pipe is too small, it must be
Set the lifting pool and the primary lifting pump, and lift it to the regulating pool.
(6) In the design of disinfection reaction tank, attention should be paid to avoid short circuit of water flow, and the inlet water should be led to the bottom of the reaction tank, with diversion in the tank.
Partition wall, from the upper part of the pool water.
(7) The design of the intermediate pool should also prevent the occurrence of dead water areas and take measures.
Open the distance between the water inlet and the water outlet.
(8) Attention should be paid to the design of the pool to facilitate cleaning and emptying. When conditions permit, it should be as high as possible.
(9) The plane area of the structure is obtained by dividing the required volume of the pool by the effective water depth, while the actual size should be in the plane.
Determine at design time.
(10) When the plane is laid out, the pools shall be concentrated as far as possible to reduce the land occupation and the number of concrete partitions.
(1 1) For convenience of operation, platforms or stairs should be set at the integrated equipment and grille.
(12) Drains and pits are set indoors to discharge the overflow water from the pool, backwashing water from the filter and emergency drainage to the outside.
(13) There should be more than 700 mm operating space above the equipment. The plane position of the equipment should be avoided under the girder as far as possible.
(14) Different from the general situation, XM wool collector should be located at the outlet end of the lift pump to prevent the sewage lift pump from being blocked.
Non-clogging pumps should be used.
(15) The equipment standby coefficient is generally one for use and one for standby. Pre-aeration fans are not needed for equipment use, and pipes are used for sewage lifting.
Pump, due to the convenience of loading and unloading, can not be installed in order to save area. Contact oxidation pool fan should be one in use and one for standby.
In the case of great changes and high standby requirements, two users and one standby can also be used. Under normal circumstances, the reclaimed water supply pump is used for one purpose and one for standby. examination
Considering the low flow at night, you can also add a small flow pump to save energy.