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Question

A sand filter is an option for filtering rainwater prior to storage.Sand and gravel will remove some contaminants, and if combined with limestone, the acidic nature
of the rainwater will be neutralized.A sand filter requires backwashing regularly to discourage bacterial growth that can create a crust layer on the sand and cause clogging of the sand’s top layer. Sediment will add to the clogging. The sand
should periodically be replaced with new sand. The sand used in these filters should be washed,screened beach or quarry sand.The filter should also have a large surface area with the outlet pipe equaling the inlet pipe size.
1. Clean filter with warm soapy water or rinse well every three to six months.
2. Check that the drop from gutter remains vertical. Check to ensure that the bulk of water is landing centrally and towards the back of the leaf and debris filter screen.
3. Check for any obstructions and signs of damage to the leaf and debris filter.
First-flush devices range in size to meet the demand of the rainwater
catchment system. These diversion devices can be part of the downspout, be separate from a tank or cistern, or be attached to a tank or cistern. They can be
below grade for large stormwater collection systems, where the harvested water is used for nonpotable purposes such as landscape irrigation, carwash supply, or toilet flushing. The size and volume depend on the amount of water being diverted to a storage system and the ultimate use of the harvested water.
For any first-flush diversion device to work efficiently—especially for potable systems—the contaminated watermust be sealed off so the rainwater flowing on to the storage cistern(s) does not siphon off the contaminated water fromthe first-flush device chamber.First-flush diverters should operate on a predetermined and set volume and the contaminated water should be sealed off from the flow of clean water.
First-flush diverters that operate on an estimated open flow rate are typically accurate enough to guarantee that most bacteria have been flushed from the roof
prior to closure. Since the goal is to not waste valuable clean water,the most efficient and safest way to ensure that the appropriate amount of water is diverted is to
assess the contamination on the roof and calculate a diversion amount based on that assessment. A set pre-sized diverter chamber with a free-floating ball and seat incorporating a flow control release valve is the optimum diversion unit.
If the water diverter does not have a self-sealing device, it is best to have it drop off a horizontal length of pipe away from the downspout so that the roof water does not drop directly into the water diverter and pick up contaminants as it travels to the cistern.

Answer 1

阿砂过滤器是一种过滤雨水之前storage.Sand和砾石将污染物去除一些选项，如果与石灰石结合，酸性性质
的雨水将被neutralized.A砂滤反冲洗需要定期来阻止细菌的生长，可以创建一个在沙滩上的沙子，造成的堵塞地壳表层层。沉积物会增加堵塞。沙子
应定期更换新砂。这些过滤器使用的沙子应清洗，筛选海滩或采石场sand.The过滤也应与插座大小相当于进水管管大面积的。
1。清洁过滤器或用温肥皂水冲洗以及每3至6个月。
2。检查从排水沟仍然垂直下降。检查以确保水的体积是登陆中央和实现的叶和碎片滤网回来。
3。检查任何阻碍和破坏叶子和杂物过滤器的迹象。
第一冲洗设备的范围的大小，以满足需求的雨水
集水系统。这些设备可以转移的downspout的一部分，从一箱或蓄水池，或附着在箱或蓄水池分开。它们可以
级以下的大型雨水收集系统，那里的水是收获的nonpotable用途，如园林灌溉，洗车供应，或冲洗厕所。大小和数量取决于水量被转移到一个存储系统和最终的收获水使用。
对于任何第一冲洗设备转移工作，饮用水系统，有效的污染watermust，尤其是被封闭，以便雨水流入到存储池（s）不虹吸关闭受污染的水其外第一冲水装置chamber.First -刷新分流器应该在一个预定的经营和设置的数量和被污染的水，应密封从清水流过。
第一，关于冲洗分流器，估计开放流量运作通常不够准确，保证大多数细菌是从屋顶刷新
之前关闭。既然目标是不浪费宝贵的清洁水，最有效和最安全的方式，以确保适量的水是被挪用
屋顶上的评估和计算一个污染转移金额的评估为基础。前一组大小与自由浮动球，并纳入一个流量控制释放阀座转向器商会是最佳分流单位。
如果水分流并没有一个自我封闭的设备，最好是把它落一管水平长度远离downspout使屋顶水不直接降入水分流，拿起污染物，因为它的旅行到水箱。